Acetabular Dysplasia and Surgical Approaches Other Than Direct Anterior Increases Risk for Malpositioning of the Acetabular Component in Total Hip Arthroplasty

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Gromov, Kirill; Greene, Meridith E; Huddleston, James I

2016-01-01

BACKGROUND: Persistent acetabular dysplasia (AD) after periacetabular osteotomy has been hypothesized to increase the risk for malpositioning of the acetabular component. In this study, we investigate whether AD is an independent risk factor for cup malpositioning during primary total hip...... arthroplasty (THA). METHODS: Patient demographics, surgical approach, presence of AD assessed using the lateral center-edge angle, and acetabular cup positioning determined using Martell Hip Analysis Suite were investigated in 836 primary THA patients enrolled in a prospective multicenter study. RESULTS: We...

Normal microscopic architecture of acetabular labrum of hip joint: a qualitative original study with clinical aspects

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Kapetanakis, Stylianos; Gkantsinikoudis, Nikolaos; Dermon, Antonios; Kommata, Vassiliki; Papathanasiou, Jannis; Soukakos, Panagiotis; Dermon, Caterina

2017-01-01

Summary Background Normal histologic architecture of acetabular labrum, regarding presence of Free Nerve Endings (FNEs) and Nerve End Organs (NEOs) has been four times described. Nevertheless, elderly cadaveric specimens and individuals were recruited, leading to considerably high unreliability probability due to microscopic degenerative alterations. Aim of this paper is to analyze distribution pattern of FNEs and NEOs in acetabular labra of healthy middle-aged individuals, configuring thus more reliably acetabular labrum microscopic profile. Materials and methods Six patients with middle age 52 ± 2.5 years were enrolled in this study. Injury of acetabular labrum and normal hip radiograph were present in all cases. Patients were all subjected to successful hip hemi-arthroplasty and derived acetabular labra were subsequently histologically processed and observed under a compound microscope. Results FNEs and NEOs were detected in all specimens. All types of NEOs were identified, including Paccini, Golgi-Mazzoni, Ruffini and Krause corpuscles. FNEs and NEOs were both in ventral part and in chondral side of labrum predominantly detected. Conclusion FNEs and NEOs presence was greater in ventral side of labrum, being thus in partial agreement with previous studies results. Further study is required, in order to elucidate the exact acetabular labrum normal microscopic anatomy. Level of evidence IV. PMID:29264339

[Quantification of acetabular coverage in normal adult].

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Lin, R M; Yang, C Y; Yu, C Y; Yang, C R; Chang, G L; Chou, Y L

1991-03-01

Quantification of acetabular coverage is important and can be expressed by superimposition of cartilage tracings on the maximum cross-sectional area of the femoral head. A practical Autolisp program on PC AutoCAD has been developed by us to quantify the acetabular coverage through numerical expression of the images of computed tomography. Thirty adults (60 hips) with normal center-edge angle and acetabular index in plain X ray were randomly selected for serial drops. These slices were prepared with a fixed coordination and in continuous sections of 5 mm in thickness. The contours of the cartilage of each section were digitized into a PC computer and processed by AutoCAD programs to quantify and characterize the acetabular coverage of normal and dysplastic adult hips. We found that a total coverage ratio of greater than 80%, an anterior coverage ratio of greater than 75% and a posterior coverage ratio of greater than 80% can be categorized in a normal group. Polar edge distance is a good indicator for the evaluation of preoperative and postoperative coverage conditions. For standardization and evaluation of acetabular coverage, the most suitable parameters are the total coverage ratio, anterior coverage ratio, posterior coverage ratio and polar edge distance. However, medial coverage and lateral coverage ratios are indispensable in cases of dysplastic hip because variations between them are so great that acetabuloplasty may be impossible. This program can also be used to classify precisely the type of dysplastic hip.

[Contact characteristics research of acetabular weight-bearing area with different internal fixation methods after compression fracture of acetabular dome].

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Xu, Bowen; Zhang, Qingsong; An, Siqi; Pei, Baorui; Wu, Xiaobo

2017-08-01

To establish the model of compression fracture of acetabular dome, and to measure the contact characteristics of acetabular weight-bearing area of acetabulum after 3 kinds of internal fixation. Sixteen fresh adult half pelvis specimens were randomly divided into 4 groups, 4 specimens each group. Group D was the complete acetabulum (control group), and the remaining 3 groups were prepared acetabular dome compression fracture model. The fractures were fixed with reconstruction plate in group A, antegrade raft screws in group B, and retrograde raft screws in group C. The pressure sensitive films were attached to the femoral head, and the axial compression test was carried out on the inverted single leg standing position. The weight-bearing area, average stress, and peak stress were measured in each group. Under the loading of 500 N, the acetabular weight-bearing area was significantly higher in group D than in other 3 groups ( P area were significantly higher in group B and group C than in group A, and the average stress and peak stress were significantly lower than in group A ( P 0.05). For the compression fracture of the acetabular dome, the contact characteristics of the weight-bearing area can not restore to the normal level, even if the anatomical reduction and rigid internal fixation were performed; compared with the reconstruction plate fixation, antegrade and retrograde raft screws fixations can increase the weight-bearing area, reduce the average stress and peak stress, and reduce the incidence of traumatic arthritis.

Modified Harrington Procedure for Acetabular Insuficiency Due to Metastatic Malignant Disease

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WI Faisham

2009-05-01

Full Text Available Extensive peri-acetabular osteolysis caused by malignant disease process is a major surgical challenge as conventional hip arthroplasty is not adequate. We describe a modified use of the Harrington procedure for acetabular insufficiency secondary to metastatic disease in twelve patients. The procedures include application of multiple threaded pins to bridge the acetabular columns, anti-protrusio cage and cemented acetabular cup. Eleven patients were able to walk pain free and achieved a mean Musculoskeletal Tumour Society Functional Score of 80 (range, 68 to 86.

Morphometric analysis of acetabular dysplasia in cerebral palsy: three-dimensional CT study.

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Gose, Shinichi; Sakai, Takashi; Shibata, Toru; Murase, Tsuyoshi; Yoshikawa, Hideki; Sugamoto, Kazuomi

2009-12-01

Three-dimensional computed tomography (3D-CT) eliminates the positioning errors and allows the clinician to more accurately assess the radiographic parameters present. To elucidate the 3D geometry of the acetabulum and the extent of hip subluxation/dislocation in patients with cerebral palsy (CP), quantitative morphometric analysis was performed using 3D-CT data. We evaluated 150 hips in 75 patients with bilateral spastic CP. The mean age of the patients was 5.4 years (range: 2.7 to 6.9 y). The fitting plane of the ilium was projected onto the coronal plane and then onto the sagittal plane, and then the angle formed with a horizontal line was defined as CTalpha (the lateral opening angle) and CTbeta (the sagittal inclination angle), respectively. The center of the acetabulum and the femoral head were defined, and the distance between these centers was divided by the femoral head diameter, defined as CT migration percentage (CTMP, %). In 123 (82%) of the 150 hips, the femoral head center was located posteriorly, superiorly, and laterally relative to the acetabular center. Large CTalpha cases tended to show large CTMP. CTalpha and CTMP were significantly larger in the cases with Gross Motor Functional Classification System (GMFCS) level IV/V and spastic quadriplegia, than in the cases with GMFCS level II/III and spastic diplegia. CTbeta showed significant correlation with the acetabular defect on the lateral 3D reconstructed images. Three-dimensional acetabular geometry and migration percentage in CP patients can be analyzed quantitatively using 3D-CT regardless of the abnormal spastic posture. The extent of acetabular dysplasia and subluxation is more severe in patients with GMFCS level IV/V and spastic quadriplesia. Level 4.

Does the optimal position of the acetabular fragment should be within the radiological normal range for all developmental dysplasia of the hip? A patient-specific finite element analysis.

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Wang, Xuyi; Peng, Jianping; Li, De; Zhang, Linlin; Wang, Hui; Jiang, Leisheng; Chen, Xiaodong

2016-10-04

The success of Bernese periacetabular osteotomy depends significantly on how extent the acetabular fragment can be corrected to its optimal position. This study was undertaken to investigate whether correcting the acetabular fragment into the so-called radiological "normal" range is the best choice for all developmental dysplasia of the hip with different severities of dysplasia from the biomechanical view? If not, is there any correlation between the biomechanically optimal position of the acetabular fragment and the severity of dysplasia? Four finite element models with different severities of dysplasia were developed. The virtual periacetabular osteotomy was performed with the acetabular fragment rotated anterolaterally to incremental center-edge angles; then, the contact area and pressure and von Mises stress in the cartilage were calculated at different correction angles. The optimal position of the acetabular fragment for patients 1, 2, and 3 was when the acetabular fragment rotated 17° laterally (with the lateral center-edge angle of 36° and anterior center-edge angle of 58°; both were slightly larger than the "normal" range), 25° laterally following further 5° anterior rotation (with the lateral center-edge angle of 31° and anterior center-edge angle of 51°; both were within the "normal" range), and 30° laterally following further 10° anterior rotation (with the lateral center-edge angle of 25° and anterior center-edge angle of 40°; both were less than the "normal" range), respectively. The optimal corrective position of the acetabular fragment is severity dependent rather than within the radiological "normal" range for developmental dysplasia of the hip. We prudently proposed that the optimal correction center-edge angle of mild, moderate, and severe developmental dysplasia of the hip is slightly larger than the "normal" range, within the "normal" range, and less than the lower limit of the "normal" range, respectively.

Assessment of trochanteric osteotomy fragment union after acetabular fracture surgery.

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Dubina, Andrew G; Wickramaratne, Niluka; O'Toole, Robert V; Manson, Theodore T

2017-02-01

Trochanteric osteotomies are performed in conjunction with standard approaches to improve surgical exposure during open reduction and internal fixation (ORIF) of acetabular fractures. The literature on total hip arthroplasty reports nonunion rates as high as 30% associated with trochanteric osteotomies; however, few data exist regarding the outcomes of trochanteric osteotomies for acetabular fracture surgery. Our hypotheses were 1) patients receiving trochanteric osteotomies during ORIF of acetabular fractures have a low rate of nonunion of the osteotomy fragment, and 2) hip abduction precautions are not necessary with digastric type osteotomies. A retrospective review was conducted to identify patients with acetabular fractures between July 2002 and June 2010 (n=734 fractures) who required trochanteric osteotomies (n=64, 9% of fractures). Forty-seven met inclusion criteria of adequate follow-up (>56days). No excluded patient experienced a complication. Fractures were classified using the Letournel-Judet classification system. Only seven (20%) of 35 patients who received digastric osteotomies had hip abduction precautions applied during the postoperative period. All study patients were shown to have radiographic union at the trochanteric osteotomy site (100% union rate, n=47). Hip abduction precautions intended to protect the osteotomy site and reduce the risk of nonunion and fixation failure were infrequently applied to patients with digastric osteotomies (20%) in this cohort. Multiple protective factors against nonunion were present in this study population compared with previous arthroplasty studies from other institutions. Trochanteric osteotomies are not associated with a significant nonunion rate, and digastric osteotomies might be safely managed without hip abduction precautions. Copyright © 2016. Published by Elsevier Ltd.

MR imaging findings of acetabular dysplasia in adults

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James, Steven; Connell, David [The Royal National Orthopaedic Hospital, Radiology Department, London, Middlesex (United Kingdom); Miocevic, Miranda; Malara, Frank; Pike, Jonathan [Victoria House Hospital, Radiology Department, Melbourne (Australia); Young, David [Melbourne Orthopaedic Group, Orthopaedic Surgery, Melbourne (Australia)

2006-06-15

To evaluate the diagnostic accuracy of MR imaging in the identification of labral and articular cartilage lesions in patients with acetabular dysplasia. Pre-operative MR imaging was performed on 27 hips in 25 consecutive patients (16 males, 9 females, age range 19-52 years, mean age 31.2 years) with radiographic evidence of acetabular dysplasia (centre-edge angle of Wiberg <20 degrees). The average duration of symptoms was 16.2 months. Two musculoskeletal radiologists assessed MR images in consensus for the presence of abnormality involving the acetabular labrum and adjacent acetabular articular cartilage. A high resolution, non-arthrographic technique was used to assess the labrum and labral chondral transitional zone. Surgical correlation was obtained in all cases by a single surgeon experienced in hip arthroscopy and ten patients with normal hip MRI were included to provide a control group. The acetabular labra in the dysplastic hips demonstrated abnormal signal intensity, and had an elongated appearance when compared with the control group (mean length 10.9 mm vs 6.4 mm). Morphological appearances in the labra included surface irregularity, fissures and cleft formation. MR imaging correctly identified the severity of chondral abnormality in 24 of 27 hips (89%) when compared with arthroscopic findings. MR imaging demonstrates an elongated labrum, focal intra-substance signal change and irregularity and fissuring of the margins in patients with acetabular dysplasia. Abnormality is also identified at the labral chondral transitional zone, where fissuring, focal clefts, chondral deficiency and subchondral cyst formation may be apparent. A high-resolution, non-arthrographic technique can provide an accurate preoperative assessment and evaluate the presence of premature osteoarthritis. (orig.)

MR imaging findings of acetabular dysplasia in adults

International Nuclear Information System (INIS)

James, Steven; Connell, David; Miocevic, Miranda; Malara, Frank; Pike, Jonathan; Young, David

2006-01-01

To evaluate the diagnostic accuracy of MR imaging in the identification of labral and articular cartilage lesions in patients with acetabular dysplasia. Pre-operative MR imaging was performed on 27 hips in 25 consecutive patients (16 males, 9 females, age range 19-52 years, mean age 31.2 years) with radiographic evidence of acetabular dysplasia (centre-edge angle of Wiberg <20 degrees). The average duration of symptoms was 16.2 months. Two musculoskeletal radiologists assessed MR images in consensus for the presence of abnormality involving the acetabular labrum and adjacent acetabular articular cartilage. A high resolution, non-arthrographic technique was used to assess the labrum and labral chondral transitional zone. Surgical correlation was obtained in all cases by a single surgeon experienced in hip arthroscopy and ten patients with normal hip MRI were included to provide a control group. The acetabular labra in the dysplastic hips demonstrated abnormal signal intensity, and had an elongated appearance when compared with the control group (mean length 10.9 mm vs 6.4 mm). Morphological appearances in the labra included surface irregularity, fissures and cleft formation. MR imaging correctly identified the severity of chondral abnormality in 24 of 27 hips (89%) when compared with arthroscopic findings. MR imaging demonstrates an elongated labrum, focal intra-substance signal change and irregularity and fissuring of the margins in patients with acetabular dysplasia. Abnormality is also identified at the labral chondral transitional zone, where fissuring, focal clefts, chondral deficiency and subchondral cyst formation may be apparent. A high-resolution, non-arthrographic technique can provide an accurate preoperative assessment and evaluate the presence of premature osteoarthritis. (orig.)

Image research on acetabular teardrop shadow by X-ray plain-film and CT

International Nuclear Information System (INIS)

Wang Xiaoxuan; Zhai Yuejie; Yu Hongguang; Yang Yijun; Zhang Daiwei; Chen Aili; Song Quanjun

2001-01-01

Objective: To evaluate the anatomical structure of bone in the formation of acetabular teardrop shadow. Methods: The acetabular teardrop shadow of the X-ray plain-film in 100 children and 300 adults, and of CT in 43 cases were analysed, measured and compared. Results: In children, teardrop shadow appeared 'U' in 80.00%, 14.00% in teardrop, 6.00% in line. In adult teardrop shadow appeared 'U' in 41.33%, 53.33% in teardrop, 5.34% in line. There were significant differences between children and adult in the frequency of 'U' and teardrop (x 2 = 43.34, P 2 = 45.62, P < 0.01). In children, inpeduncle of teardrop shadow was formed of middle 1/3 substantia-line of acetabular concavity inside of pelvis; outpeduncle was formed of middle 1/3 substantia-line of bottom of acetabular. In adult, inpeduncle was formed of middle 1/3 or back 1/3 substantia line of acetabular concavity inside of pelvis; outpeduncle was formed of middle 1/3 or back 1/3 substantia-line of bottom of acetabular. Conclusion: In children, acetabular teardrop shadow was mainly formed of middle 1/3 bone of acetabular concavity. In adult, middle 1/3 or back 1/3 bone of acetabular concavity contribute to the shadow. The ahead 1/3 bone of acetabular concavity is not involved

Superior dislocation hip with anterior column acetabular fracture ...

African Journals Online (AJOL)

Superior variety of anterior dislocation of the hip is a rare injury. Its occurrence with acetabular fractures has been documented infrequently. We report a case of superior dislocation of the hip with anterior column acetabular fracture. Open reduction of the hip and internal fixation of the fracture was carried out using a twin ...

The Evolution of the Cup-Cage Technique for Major Acetabular Defects: Full and Half Cup-Cage Reconstruction.

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Sculco, Peter K; Ledford, Cameron K; Hanssen, Arlen D; Abdel, Matthew P; Lewallen, David G

2017-07-05

Complex acetabular reconstruction for major bone loss can require advanced methods such as the use of a cup-cage construct. The purpose of this study was to review outcomes after the initial development of the cup-cage technique and the subsequent evolution to the use of a half cup-cage construct. We performed a retrospective, single-center review of 57 patients treated with cup-cage reconstruction for major acetabular bone loss. All patients had major acetabular defects graded as Paprosky Type 2B through 3B, with 34 (60%) having an associated pelvic discontinuity. Thirty patients received a full cup-cage construct and 27, a half cup-cage construct. The mean follow-up was 5 years. Both the full and half cup-cage cohorts demonstrated significantly improved Harris hip score (HHS) values, from 36 to 72 at a minimum of 2 years of follow-up (p cup-cage constructs and 6 (22%) of the half cup-cage constructs. One patient with a full cup-cage construct underwent re-revision of the acetabular component for progressive migration and aseptic loosening. Short-term survivorship free from re-revision for any cause or reoperation was 89% (83% and 96% for full and half cup-cage cohorts, respectively). Both full and half cup-cage constructs demonstrated successful clinical outcomes and survivorship in the treatment of major acetabular defects and pelvic discontinuity. Each method is utilized on the basis of individual intraoperative findings, including the extent and pattern of bone loss, the quality and location of host bone remaining after preparation, and the presence of pelvic discontinuity. Longer-term follow-up is required to understand the durability of these constructs in treating major acetabular defects and pelvic discontinuity. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

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2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint (hemi-hip) acetabular metal cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip) acetabular...

Ultrasound-guided supra-acetabular pin placement in pelvic external fixation: description of a surgical technique and results.

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Chana-Rodríguez, Francisco; Cuervas-Mons, Manuel; Rojo-Manaute, José; Mora, Félix; Arnal, Juan; Vaquero-Martín, Javier

2017-11-01

Pelvic fracture in trauma patients can lead to hemodynamic instability. External fixation is a treatment capable of stabilizing these injuries in the context of damage control surgery. Supra-acetabular pin offers the greater biomechanical stability but requires the use of intraoperative fluoroscopy. The aim of this study was to analyze our results for an ultrasound-guided supra-acetabular pinning. Cross-sectional study with cadaveric specimens. Ultrasound-guided pin placement assessed by fluoroscopy and dissection. Fourteen ultrasound-guided supra-acetabular pins were placed in seven cadaveric specimens. Excellent placement in all cases, evaluated with radiological control. Good qualitative bone fixation after dissection. One femoral cutaneous nerve was not found during anatomic dissection and was assumed injured. Ultrasound-guided supra-acetabular pin placement is a feasible and effective technique. Our study indicates that pin placement without intraoperative fluoroscopy is feasible without compromising the reliability of its placement. © 2017 Elsevier Ltd. All rights reserved.

Acetabular labral tears in patients with sports injury.

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Kang, Chan; Hwang, Deuk-Soo; Cha, Soo-Min

2009-12-01

We wanted to investigate acetabular labral tears and their correlation with femoroacetabular impingement in patients with sports injury. Among 111 patients who were diagnosed with the acetabular labral tears after arthroscopic treatment from January 2004 to December 2007, we selected 41 patients with sports injury. There were 12 cases of Taekwondo injury, 5 of golf injury, 4 of soccer injury, 3 of gymnastics injury, 2 of Hapkido injury, 2 of aerobics injury, 2 of rock-climbing injury, 2 of fitness training injury and 9 of other sports injuries. We checked the subtypes of acetabular labral tears and the accompanying femoroacetabular impingement. For the cases with accompanying femoroacetabular impingement, we investigated the subtypes according to the types of sports, gender and age. At last follow-up, we checked the Harris Hip Score (HHS), the Hip Outcome Score (HOS) sports scale and the percentage of patients who returned to their sports activity. The average age of symptomatic onset was 26 years (range, 12 to 65 years). The ratio of males to females was 29 : 12. An average duration of the hip pain was 17 months (range, 1 to 60 months). The degenerative type of acetabular labral tears was the most prevalent with 32 cases (78%), and there were 9 cases (22%) of the partial tear type. Thirty cases (73%) were accompanied by femoroacetabular impingement. The average age of the 23 cases (56%) of the cam-type was 23 years (range, 12 to 48 years), and it was more likely to occur in men (87%) and for people practicing martial arts such as Taekwondo or Hapkido. An average age of the 5 cases (12%) of the pincer-type was 26 (range, 16 to 43 years), it usually occurred in women (60%) and for non-martial arts such as golf and gymnastics. There were 2 cases of the mixed type (cam + pincer-type). At 27 months follow-up, the HHS was 61 to 92 points, the HOS sports scale increased 43 to 75%, and the rate of returning to sports was 71%. In spite of the early expression of symptoms

Biochemical and Cellular Assessment of Acetabular Chondral Flaps Identified During Hip Arthroscopy.

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Hariri, Sanaz; Truntzer, Jeremy; Smith, Robert Lane; Safran, Marc R

2015-06-01

To analyze chondral flaps debrided during hip arthroscopy to determine their biochemical and cellular composition. Thirty-one full-thickness acetabular chondral flaps were collected during hip arthroscopy. Biochemical analysis was undertaken in 21 flaps from 20 patients, and cellular viability was determined in 10 flaps from 10 patients. Biochemical analysis included concentrations of (1) DNA (an indicator of chondrocyte content), (2) hydroxyproline (an indicator of collagen content), and (3) glycosaminoglycan (an indicator of chondrocyte biosynthesis). Higher values for these parameters indicated more healthy tissue. The flaps were examined to determine the percentage of viable chondrocytes. The percentage of acetabular chondral flap specimens that had concentrations within 1 SD of the mean values reported in previous normal cartilage studies was 38% for DNA, 0% for glycosaminoglycan, and 43% for hydroxyproline. The average cellular viability of our acetabular chondral flap specimens was 39% (SD, 14%). Only 2 of the 10 specimens had more than half the cells still viable. There was no correlation between (1) the gross examination of the joint or knowledge of the patient's demographic characteristics and symptoms and (2) biochemical properties and cell viability of the flap, with one exception: a degenerative appearance of the surrounding cartilage correlated with a higher hydroxyproline concentration. Although full-thickness acetabular chondral flaps can appear normal grossly, the biochemical properties and percentage of live chondrocytes in full-thickness chondral flaps encountered in hip arthroscopy show that this tissue is not normal. There has been recent interest in repairing chondral flaps encountered during hip arthroscopy. These data suggest that acetabular chondral flaps are not biochemically and cellularly normal. Although these flaps may still be valuable mechanically and/or as a scaffold in some conductive or inductive capacity, further study is

Early failure mechanisms of constrained tripolar acetabular sockets used in revision total hip arthroplasty.

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Cooke, Christopher C; Hozack, William; Lavernia, Carlos; Sharkey, Peter; Shastri, Shani; Rothman, Richard H

2003-10-01

Fifty-eight patients received an Osteonics constrained acetabular implant for recurrent instability (46), girdlestone reimplant (8), correction of leg lengthening (3), and periprosthetic fracture (1). The constrained liner was inserted into a cementless shell (49), cemented into a pre-existing cementless shell (6), cemented into a cage (2), and cemented directly into the acetabular bone (1). Eight patients (13.8%) required reoperation for failure of the constrained implant. Type I failure (bone-prosthesis interface) occurred in 3 cases. Two cementless shells became loose, and in 1 patient, the constrained liner was cemented into an acetabular cage, which then failed by pivoting laterally about the superior fixation screws. Type II failure (liner locking mechanism) occurred in 2 cases. Type III failure (femoral head locking mechanism) occurred in 3 patients. Seven of the 8 failures occurred in patients with recurrent instability. Constrained liners are an effective method for treatment during revision total hip arthroplasty but should be used in select cases only.

The nerve endings of the acetabular labrum.

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Kim, Y T; Azuma, H

1995-11-01

The nerve endings of the human acetabular labrum were investigated. Twenty-three acetabular labra were obtained from 24 fresh human cadavers, stained with Suzuki's silver impregnation and an immunohistochemical technique for neurogenic specific protein S-100, and examined by light and electron microscopy. Ramified free nerve endings were seen in all specimens by silver staining, and also were observed by the immunohistochemical technique for S-100 protein. Sensory nerve end organs, such as a Vater-Pacini corpuscle, Golgi-Mazzoni corpuscle, Ruffini corpuscle, and articular corpuscle (Krause corpuscle), were observed by silver staining. Collagen fibers were scattered sparsely in the superficial layer of the labrum, and nerve endings were observed mostly in this region. Collagen fibers were sparse, and nerve endings also were observed in some regions among the collagen fiber bundles in the inner layer. Innervation of the acetabular labrum was confirmed in this study, suggesting that nerve endings in the labrum may be involved in nociceptive and proprioceptive mechanisms.

Validation of a new radiographic measurement of acetabular version: the transverse axis distance (TAD).

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Nitschke, Ashley; Lambert, Jeffery R; Glueck, Deborah H; Jesse, Mary Kristen; Mei-Dan, Omer; Strickland, Colin; Petersen, Brian

2015-11-01

This study has three aims: (1) validate a new radiographic measure of acetabular version, the transverse axis distance (TAD) by showing equivalent TAD accuracy in predicting CT equatorial acetabular version when compared to a previously validated, but more cumbersome, radiographic measure, the p/a ratio; (2) establish predictive equations of CT acetabular version from TAD; (3) calculate a sensitive and specific cut point for predicting excessive CT acetabular anteversion using TAD. A 14-month retrospective review was performed of patients who had undergone a dedicated MSK CT pelvis study and who also had a technically adequate AP pelvis radiograph. Two trained observers measured the radiographic p/a ratio, TAD, and CT acetabular equatorial version for 110 hips on a PACS workstation. Mixed model analysis was used to find prediction equations, and ROC analysis was used to evaluate the diagnostic accuracy of p/a ratio and TAD. CT equatorial acetabular version can accurately be predicted from either p/a ratio (p TAD (p TAD are comparable (p =0.46). Patients whose TAD is higher than 17 mm may have excessive acetabular anteversion. For that cutpoint, the sensitivity of TAD is 0.73, with specificity of 0.82. TAD is an accurate radiographic predictor of CT acetabular anteversion and provides an easy-to-use and intuitive point-of-care assessment of acetabular version in patients with hip pain.

Acetabular paralabral cyst causing compression of the sciatic nerve

Directory of Open Access Journals (Sweden)

Caoimhe Byrne, MB BCh BAO

2017-12-01

Full Text Available Acetabular paralabral cysts are common. They vary in their clinical presentation and may be asymptomatic or cause pain and restriction at the hip joint. In rare instances they may cause symptoms by compressing local neurovascular structures. We report a case of symptomatic compression of the sciatic nerve by a posteriorly displaced acetabular paralabral cyst.

A Pilot Study of Augmented Reality Technology Applied to the Acetabular Cup Placement During Total Hip Arthroplasty.

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Ogawa, Hiroyuki; Hasegawa, Seiichirou; Tsukada, Sachiyuki; Matsubara, Masaaki

2018-06-01

We developed an acetabular cup placement device, the AR-HIP system, using augmented reality (AR). The AR-HIP system allows the surgeon to view an acetabular cup image superimposed in the surgical field through a smartphone. The smartphone also shows the placement angle of the acetabular cup. This preliminary study was performed to assess the accuracy of the AR-HIP system for acetabular cup placement during total hip arthroplasty (THA). We prospectively measured the placement angles using both a goniometer and AR-HIP system in 56 hips of 54 patients undergoing primary THA. We randomly determined the order of intraoperative measurement using the 2 devices. At 3 months after THA, the placement angle of the acetabular cup was measured on computed tomography images. The primary outcome was the absolute value of the difference between intraoperative and postoperative computed tomography measurements. The measurement angle using AR-HIP was significantly more accurate in terms of radiographic anteversion than that using a goniometer (2.7° vs 6.8°, respectively; mean difference 4.1°; 95% confidence interval, 3.0-5.2; P < .0001). There was no statistically significant difference in terms of radiographic inclination (2.1° vs 2.6°; mean difference 0.5°; 95% confidence interval, -1.1 to 0.1; P = .13). In this pilot study, the AR-HIP system provided more accurate information regarding acetabular cup placement angle than the conventional method. Further studies are required to confirm the utility of the AR-HIP system as a navigation tool. Copyright © 2018 Elsevier Inc. All rights reserved.

Validation of a new radiographic measurement of acetabular version: the transverse axis distance (TAD)

Energy Technology Data Exchange (ETDEWEB)

Nitschke, Ashley [University of Colorado School of Medicine, University of Colorado Denver, Division of Musculoskeletal Radiology, Department of Radiology, Aurora, CO (United States); Lambert, Jeffery R. [University of Colorado, Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO (United States); Glueck, Deborah H. [University of Colorado, Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO (United States); University of Colorado School of Medicine, University of Colorado Denver, Department of Radiology, Aurora, CO (United States); Jesse, Mary Kristen; Strickland, Colin [University of Colorado School of Medicine, University of Colorado Denver, Division of Musculoskeletal Radiology, Department of Radiology and Orthopaedics, Aurora, CO (United States); Mei-Dan, Omer [University of Colorado School of Medicine, University of Colorado Denver, Division of Sports Medicine and Hip Preservation, Department of Orthopaedics, Aurora, CO (United States); Petersen, Brian [University of Colorado School of Medicine, University of Colorado Denver, Division of Musculoskeletal Radiology, Department of Radiology and Orthopaedics, Aurora, CO (United States); Inland Imaging, Division of Musculoskeletal Radiology, Spokane, WA (United States)

2015-11-15

This study has three aims: (1) validate a new radiographic measure of acetabular version, the transverse axis distance (TAD) by showing equivalent TAD accuracy in predicting CT equatorial acetabular version when compared to a previously validated, but more cumbersome, radiographic measure, the p/a ratio; (2) establish predictive equations of CT acetabular version from TAD; (3) calculate a sensitive and specific cut point for predicting excessive CT acetabular anteversion using TAD. A 14-month retrospective review was performed of patients who had undergone a dedicated MSK CT pelvis study and who also had a technically adequate AP pelvis radiograph. Two trained observers measured the radiographic p/a ratio, TAD, and CT acetabular equatorial version for 110 hips on a PACS workstation. Mixed model analysis was used to find prediction equations, and ROC analysis was used to evaluate the diagnostic accuracy of p/a ratio and TAD. CT equatorial acetabular version can accurately be predicted from either p/a ratio (p < 0.001) or TAD (p < 0.001). The diagnostic accuracies of p/a ratio and TAD are comparable (p =0.46). Patients whose TAD is higher than 17 mm may have excessive acetabular anteversion. For that cutpoint, the sensitivity of TAD is 0.73, with specificity of 0.82. TAD is an accurate radiographic predictor of CT acetabular anteversion and provides an easy-to-use and intuitive point-of-care assessment of acetabular version in patients with hip pain. (orig.)

Validation of a new radiographic measurement of acetabular version: the transverse axis distance (TAD)

International Nuclear Information System (INIS)

Nitschke, Ashley; Lambert, Jeffery R.; Glueck, Deborah H.; Jesse, Mary Kristen; Strickland, Colin; Mei-Dan, Omer; Petersen, Brian

2015-01-01

This study has three aims: (1) validate a new radiographic measure of acetabular version, the transverse axis distance (TAD) by showing equivalent TAD accuracy in predicting CT equatorial acetabular version when compared to a previously validated, but more cumbersome, radiographic measure, the p/a ratio; (2) establish predictive equations of CT acetabular version from TAD; (3) calculate a sensitive and specific cut point for predicting excessive CT acetabular anteversion using TAD. A 14-month retrospective review was performed of patients who had undergone a dedicated MSK CT pelvis study and who also had a technically adequate AP pelvis radiograph. Two trained observers measured the radiographic p/a ratio, TAD, and CT acetabular equatorial version for 110 hips on a PACS workstation. Mixed model analysis was used to find prediction equations, and ROC analysis was used to evaluate the diagnostic accuracy of p/a ratio and TAD. CT equatorial acetabular version can accurately be predicted from either p/a ratio (p < 0.001) or TAD (p < 0.001). The diagnostic accuracies of p/a ratio and TAD are comparable (p =0.46). Patients whose TAD is higher than 17 mm may have excessive acetabular anteversion. For that cutpoint, the sensitivity of TAD is 0.73, with specificity of 0.82. TAD is an accurate radiographic predictor of CT acetabular anteversion and provides an easy-to-use and intuitive point-of-care assessment of acetabular version in patients with hip pain. (orig.)

Three-dimensional finite analysis of acetabular contact pressure and contact area during normal walking.

Science.gov (United States)

Wang, Guangye; Huang, Wenjun; Song, Qi; Liang, Jinfeng

2017-11-01

This study aims to analyze the contact areas and pressure distributions between the femoral head and mortar during normal walking using a three-dimensional finite element model (3D-FEM). Computed tomography (CT) scanning technology and a computer image processing system were used to establish the 3D-FEM. The acetabular mortar model was used to simulate the pressures during 32 consecutive normal walking phases and the contact areas at different phases were calculated. The distribution of the pressure peak values during the 32 consecutive normal walking phases was bimodal, which reached the peak (4.2 Mpa) at the initial phase where the contact area was significantly higher than that at the stepping phase. The sites that always kept contact were concentrated on the acetabular top and leaned inwards, while the anterior and posterior acetabular horns had no pressure concentration. The pressure distributions of acetabular cartilage at different phases were significantly different, the zone of increased pressure at the support phase distributed at the acetabular top area, while that at the stepping phase distributed in the inside of acetabular cartilage. The zones of increased contact pressure and the distributions of acetabular contact areas had important significance towards clinical researches, and could indicate the inductive factors of acetabular osteoarthritis. Copyright © 2016. Published by Elsevier Taiwan.

Acetabular paralabral cyst: an uncommon cause of sciatica

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Sherman, P.M.; Sanders, T.G. [Department of Radiology, Wilford Hall Medical Center, 2200 Bergquist Drive, Ste. 1, Lackland AFB, TX 78236 (United States); Matchette, M.W. [University of Texas Medical School, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900 (United States); Parsons, T.W. [Department of Orthopedic Surgery, Wilford Hall Medical Center, 2200 Bergquist Drive, Ste. 1, Lackland AFB, TX 78236 (United States)

2003-02-01

The association between tears of the acetabular labrum and paralabral cysts has been well documented, and magnetic resonance imaging (MRI) has been shown to be the most accurate noninvasive method of depicting not only the normal anatomic structures of the hip, but also the common pathologic processes such as labral tears and paralabral cysts. We present the case of an acetabular paralabral cyst that resulted in clinically symptomatic compression of the sciatic nerve. (orig.)

Acetabular paralabral cyst: an uncommon cause of sciatica

International Nuclear Information System (INIS)

Sherman, P.M.; Sanders, T.G.; Matchette, M.W.; Parsons, T.W.

2003-01-01

The association between tears of the acetabular labrum and paralabral cysts has been well documented, and magnetic resonance imaging (MRI) has been shown to be the most accurate noninvasive method of depicting not only the normal anatomic structures of the hip, but also the common pathologic processes such as labral tears and paralabral cysts. We present the case of an acetabular paralabral cyst that resulted in clinically symptomatic compression of the sciatic nerve. (orig.)

Three-dimensional computed tomography analysis of non-osteoarthritic adult acetabular dysplasia

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Ito, Hiroshi; Matsuno, Takeo; Hirayama, Teruhisa; Tanino, Hiromasa; Yamanaka, Yasuhiro [Asahikawa Medical College, Department of Orthopaedic Surgery, Asahikawa (Japan); Minami, Akio [Hokkaido University School of Medicine, Department of Orthopaedic Surgery, Sapporo (Japan)

2009-02-15

Little data exists on the original morphology of acetabular dysplasia obtained from patients without radiographic advanced osteoarthritic changes. The aim of this study was to investigate the distribution and degree of acetabular dysplasia in a large number of patients showing no advanced degenerative changes using three-dimensional computed tomography (3DCT). Eighty-four dysplastic hips in 55 consecutive patients were studied. All 84 hips were in pre- or early osteoarthritis without radiographic evidence of joint space narrowing, formation of osteophytes or cysts, or deformity of femoral heads. The mean age at the time of CT scan was 35 years (range 15-64 years). 3D images were reconstructed and analyzed using recent computer imaging software (INTAGE Realia and Volume Player). Deficiency types and degrees of acetabular dysplasia were precisely evaluated using these computer software. The average Harris hip score at CT scans was 82 points. Twenty-two hips (26%) were classified as anterior deficiency, 17 hips (20%) as posterior deficiency, and 45 hips (54%) as lateral deficiency. No significant difference was found in the Harris hip score among these groups. The analysis of various measurements indicated wide variations. There was a significant correlation between the Harris hip score and the acetabular coverage (p < 0.001). Our results indicated wide variety of deficiency type and degree of acetabular dysplasia. Hips with greater acetabular coverage tended to have a higher Harris hip score. (orig.)

Three-dimensional computed tomography analysis of non-osteoarthritic adult acetabular dysplasia

International Nuclear Information System (INIS)

Ito, Hiroshi; Matsuno, Takeo; Hirayama, Teruhisa; Tanino, Hiromasa; Yamanaka, Yasuhiro; Minami, Akio

2009-01-01

Little data exists on the original morphology of acetabular dysplasia obtained from patients without radiographic advanced osteoarthritic changes. The aim of this study was to investigate the distribution and degree of acetabular dysplasia in a large number of patients showing no advanced degenerative changes using three-dimensional computed tomography (3DCT). Eighty-four dysplastic hips in 55 consecutive patients were studied. All 84 hips were in pre- or early osteoarthritis without radiographic evidence of joint space narrowing, formation of osteophytes or cysts, or deformity of femoral heads. The mean age at the time of CT scan was 35 years (range 15-64 years). 3D images were reconstructed and analyzed using recent computer imaging software (INTAGE Realia and Volume Player). Deficiency types and degrees of acetabular dysplasia were precisely evaluated using these computer software. The average Harris hip score at CT scans was 82 points. Twenty-two hips (26%) were classified as anterior deficiency, 17 hips (20%) as posterior deficiency, and 45 hips (54%) as lateral deficiency. No significant difference was found in the Harris hip score among these groups. The analysis of various measurements indicated wide variations. There was a significant correlation between the Harris hip score and the acetabular coverage (p < 0.001). Our results indicated wide variety of deficiency type and degree of acetabular dysplasia. Hips with greater acetabular coverage tended to have a higher Harris hip score. (orig.)

The use of an Ossis custom 3D-printed tri-flanged acetabular implant for major bone loss: minimum 2-year follow-up: Short title: Ossis custom 3D-Printed tri-flanged acetabular implant.

Science.gov (United States)

Kieser, David C; Ailabouni, Ramez; Kieser, Sandra C J; Wyatt, Michael C; Armour, Paul C; Coates, Mark H; Hooper, Gary J

2018-05-01

Custom 3D-printed acetabular implants are a new technology used in hip surgery with ever-increasing frequency. They offer patient-specific implants to optimise filling of bone defects and implant-bone contact, without the need for excessive bone resection. This is a retrospective cohort study of 46 consecutive patients who underwent an Ossis unilateral custom 3D-printed acetabular implant. Clinical (Oxford Hip Score OHS-60), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Harris Hip Score (HHS) and radiological (restoration of biomechanical hip centre, osteointegration, wear, heterotrophic ossification) results were assessed. Patient mean age was 68 years and follow-up was 38 months (minimum 24 months). 10 patients were excluded from the outcome analysis; 2 patients died, 1 required revision for deep infection and 7 were lost to follow-up. Of the 36 patients included, 21 had severe osteolysis. 7 were revised for infection, 3 for tumoural defects, 3 for metallosis, 1 for dysplasia and 1 for trauma (Paprosky 2a [n=6], 2b [n=2], 2c [n=5], 3a [n=6], 3b [n=11], pelvic dissociation [n=6]). OHS significantly improved postoperatively (16-8-48.4 p=0.027). Postoperative functional scores were good (WOMAC 98; HHS 79). The biomechanical hip centre was restored in all patients. 1 patient had early implant migration with subsequent stabilisation. 2 patients had radiographs concerning for failure of osteointegration. 1 patient had recurrent dislocations. The mid-term results of the Ossis custom 3D-printed tri-flanged acetabular implant for the management of severe acetabular defects are encouraging. The improvement in functional scores and radiographic outcomes are comparable to similar designs. In addition, no cases have required revision for aseptic loosening.

Acetabular fractures: what radiologists should know and how 3D CT can aid classification.

Science.gov (United States)

Scheinfeld, Meir H; Dym, Akiva A; Spektor, Michael; Avery, Laura L; Dym, R Joshua; Amanatullah, Derek F

2015-01-01

Correct recognition, description, and classification of acetabular fractures is essential for efficient patient triage and treatment. Acetabular fractures may result from high-energy trauma or low-energy trauma in the elderly. The most widely used acetabular fracture classification system among radiologists and orthopedic surgeons is the system of Judet and Letournel, which includes five elementary (or elemental) and five associated fractures. The elementary fractures are anterior wall, posterior wall, anterior column, posterior column, and transverse. The associated fractures are all combinations or partial combinations of the elementary fractures and include transverse with posterior wall, T-shaped, associated both column, anterior column or wall with posterior hemitransverse, and posterior column with posterior wall. The most unique fracture is the associated both column fracture, which completely dissociates the acetabular articular surface from the sciatic buttress. Accurate categorization of acetabular fractures is challenging because of the complex three-dimensional (3D) anatomy of the pelvis, the rarity of certain acetabular fracture variants, and confusing nomenclature. Comparing a 3D image of the fractured acetabulum with a standard diagram containing the 10 Judet and Letournel categories of acetabular fracture and using a flowchart algorithm are effective ways of arriving at the correct fracture classification. Online supplemental material is available for this article. (©)RSNA, 2015.

Posterior column acetabular fracture fixation using a W-shaped angular plate: A biomechanical analysis.

Directory of Open Access Journals (Sweden)

Ke Su

Full Text Available The purpose of this study was to compare the stability and feasibility of four fixation constructs in a posterior column acetabular fracture: one reconstruction plate, one reconstruction plate and lag screw, two reconstruction plates, and a W-shaped acetabular angular plate.Twenty embalmed cadaveric pelvises with a posterior column acetabular fractures were allocated to one of four groups: 1 a reconstruction plate, 2 a reconstruction plate with a posterior column lag screw, 3 double reconstruction plates, and 4 a W-shaped acetabular angular plate. These constructs were mechanically loaded on a testing machine, and construct stiffness values were measured. Strain gauges were utilized to measure the mechanical behavior in the condition of compressive force.Final stiffness was not different between the two reconstruction plates (445.81±98.30 N/mm and the W-shaped acetabular angular plate (447.43±98.45 N/mm, p = 0.524, both of which were superior to a single reconstruction plate (248.90±61.95 N/mm and a combined plate and lag screw (326.41±94.34 N/mm. Following the fixation of the W-shaped acetabular angular plate, the strain distribution was similar to the intact condition around the acetabulum. The parameters of the W-shaped acetabular angular plate that were observed at the superior region of the acetabulum were less than those of a single reconstruction plate (p<0.05, a single reconstruction plate with lag screw (p<0.05, and two reconstruction plates (p<0.05.The novel W-shaped acetabular angular plate fixation technique was able to provide the biomechanically stiffest construct for stabilization of a posterior column acetabular fracture; it also resulted in a partial restoration of joint loading parameters toward the intact state.

Optimization of technique for insertion of implants at the supra-acetabular corridor in pelvis and acetabular surgery.

Science.gov (United States)

Tosounidis, Theodoros H; Mauffrey, Cyril; Giannoudis, Peter V

2018-01-01

The technique for application of implants at the sciatic buttress has been well described in the pelvic and acetabular fracture reconstruction literature. We described a new use of the inlet-obturator oblique view for the identification of the anterior inferior iliac spine, which is the entry point of implants, and we provide a detailed fluoroscopic and radiographic description of this view. A small series of 15 patients who underwent an application of an anterior inferior pelvic external (supra-acetabular) fixator via this technique is presented. We consider the use of the obturator oblique for the identification of the entry point unnecessary, and we advocate for the use of only the inlet-obturator oblique and iliac oblique views when implants are applied to the sciatic buttress.

Computer assisted surgery in preoperative planning of acetabular fracture surgery: state of the art.

Science.gov (United States)

Boudissa, Mehdi; Courvoisier, Aurélien; Chabanas, Matthieu; Tonetti, Jérôme

2018-01-01

The development of imaging modalities and computer technology provides a new approach in acetabular surgery. Areas covered: This review describes the role of computer-assisted surgery (CAS) in understanding of the fracture patterns, in the virtual preoperative planning of the surgery and in the use of custom-made plates in acetabular fractures with or without 3D printing technologies. A Pubmed internet research of the English literature of the last 20 years was carried out about studies concerning computer-assisted surgery in acetabular fractures. The several steps for CAS in acetabular fracture surgery are presented and commented by the main author regarding to his personal experience. Expert commentary: Computer-assisted surgery in acetabular fractures is still initial experiences with promising results. Patient-specific biomechanical models considering soft tissues should be developed to allow a more realistic planning.

Decreased Lumbar Lordosis and Deficient Acetabular Coverage Are Risk Factors for Subchondral Insufficiency Fracture.

Science.gov (United States)

Jo, Woo Lam; Lee, Woo Suk; Chae, Dong Sik; Yang, Ick Hwan; Lee, Kyoung Min; Koo, Kyung Hoi

2016-10-01

Subchondral insufficiency fracture (SIF) of the femoral head occurs in the elderly and recipients of organ transplantation. Osteoporosis and deficient lateral coverage of the acetabulum are known risk factors for SIF. There has been no study about relation between spinopelvic alignment and anterior acetabular coverage with SIF. We therefore asked whether a decrease of lumbar lordosis and a deficiency in the anterior acetabular coverage are risk factors. We investigated 37 patients with SIF. There were 33 women and 4 men, and their mean age was 71.5 years (59-85 years). These 37 patients were matched with 37 controls for gender, age, height, weight, body mass index and bone mineral density. We compared the lumbar lordosis, pelvic incidence, pelvic tilt, sacral slope, acetabular index, acetabular roof angle, acetabular head index, anterior center-edge angle and lateral center-edge angle. Lumbar lordosis, pelvic tilt, sacral slope, lateral center edge angle, anterior center edge angle, acetabular index and acetabular head index were significantly different between SIF group and control group. Lumbar lordosis (OR = 1.11), lateral center edge angle (OR = 1.30) and anterior center edge angle (OR = 1.27) had significant associations in multivariate analysis. Decreased lumbar lordosis and deficient anterior coverage of the acetabulum are risk factors for SIF as well as decreased lateral coverage of the acetabulum.

The effect of variable size posterior wall acetabular fractures on contact characteristics of the hip joint.

Science.gov (United States)

Olson, S A; Bay, B K; Pollak, A N; Sharkey, N A; Lee, T

1996-01-01

The indications for open reduction and internal fixation of posterior wall acetabular fractures associated with a clinically stable hip joint are unclear. In previous work a large posterior wall defect (27% articular surface area) resulted in significant alteration of load transmission across the hip; specifically, there was a transition from evenly distributed loading along the acetabular articular surface to loading concentrated mainly in the superior portion of the articular surface during simulated single leg stance. However, the majority of posterior wall fractures involve a smaller amount of the articular surface. Posterior wall acetabular fractures not associated with instability of the hip are commonly treated nonoperatively. This practice does not account for the size of the posterior wall fracture. To study the biomechanical consequences of variably sized articular defects, a laboratory experiment was conducted evaluating three progressively larger posterior wall defects of the acetabulum during simulated single leg stance using superlow Fuji prescale film (Itochu International, New York): (a) 1/3 articular surface width through a 50 degrees arc along the posterior wall of the acetabulum, (b) 2/3, and (c) 3/3 articular width defects through the same 50 degrees arc along the posterior wall of the acetabulum. In the intact acetabulum, 48% of the total articular contact was located in the superior acetabulum. Twenty-eight percent of articular contact was in the anterior wall region of the acetabulum and 24% in the posterior wall region. After the 1/3 width posterior wall defect, 64% of the articular contact was located in the superior acetabulum (p = 0.0011). The 2/3 width posterior wall defect resulted in 71% of articular contact area being located in the superior acetabulum (p = 0.0006). After the 3/3 width posterior wall defect, 77% of articular contact was located in the superior acetabulum, significantly greater than the intact condition (p < 0

T2* Mapping Provides Information That Is Statistically Comparable to an Arthroscopic Evaluation of Acetabular Cartilage.

Science.gov (United States)

Morgan, Patrick; Nissi, Mikko J; Hughes, John; Mortazavi, Shabnam; Ellerman, Jutta

2017-07-01

Objectives The purpose of this study was to validate T2* mapping as an objective, noninvasive method for the prediction of acetabular cartilage damage. Methods This is the second step in the validation of T2*. In a previous study, we established a quantitative predictive model for identifying and grading acetabular cartilage damage. In this study, the model was applied to a second cohort of 27 consecutive hips to validate the model. A clinical 3.0-T imaging protocol with T2* mapping was used. Acetabular regions of interest (ROI) were identified on magnetic resonance and graded using the previously established model. Each ROI was then graded in a blinded fashion by arthroscopy. Accurate surgical location of ROIs was facilitated with a 2-dimensional map projection of the acetabulum. A total of 459 ROIs were studied. Results When T2* mapping and arthroscopic assessment were compared, 82% of ROIs were within 1 Beck group (of a total 6 possible) and 32% of ROIs were classified identically. Disease prediction based on receiver operating characteristic curve analysis demonstrated a sensitivity of 0.713 and a specificity of 0.804. Model stability evaluation required no significant changes to the predictive model produced in the initial study. Conclusions These results validate that T2* mapping provides statistically comparable information regarding acetabular cartilage when compared to arthroscopy. In contrast to arthroscopy, T2* mapping is quantitative, noninvasive, and can be used in follow-up. Unlike research quantitative magnetic resonance protocols, T2* takes little time and does not require a contrast agent. This may facilitate its use in the clinical sphere.

Comparison of acetabular reamings during hip resurfacing versus uncemented total hip arthroplasty.

LENUS (Irish Health Repository)

Brennan, S A

2009-04-01

PURPOSE: To compare the quantity of bone removed from the acetabulum during resurfacing hip arthroplasty versus uncemented total hip arthroplasty (THA). METHODS: 62 consecutive patients with osteoarthritis of the hip were prospectively studied. 24 men and 7 women aged 40 to 86 (mean, 59) years underwent Birmingham hip resurfacing. 13 men and 18 women aged 34 to 88 (mean, 61) years underwent uncemented THA using the trident acetabular cup. Obese elderly women at risk of femoral neck fracture and patients with large subchondral pseudocysts or a history of avascular necrosis of the femoral head were assigned to uncemented THA. Acetabular reamings were collected; marginal osteophytes were not included. The reamings were dehydrated, defatted, and weighed. RESULTS: The mean weight of acetabular reamings was not significantly different between patients undergoing hip resurfacing and uncemented THA (p=0.57). CONCLUSION: In hip resurfacing, the use of an appropriately small femoral component avoids oversizing the acetabular component and removal of excessive bone stock.

MRI morphometric hip comparison analysis of anterior acetabular labral tears

International Nuclear Information System (INIS)

Aly, Abdel Rahman; Rajasekaran, Sathish; Obaid, Haron

2013-01-01

Anterior (3 o'clock) acetabular labral tears (AALTs) have been reported to be associated with iliopsoas impingement (IPI). However, no study has examined the association between anatomical bony variables of the hip joint and AALTs. The purpose of this study was to evaluate the association between AALTs, femoroacetabular impingement (FAI) and other bony variables of the hip. Seventy-six out of 274 hip MRI records met the inclusion criteria. Two independent blinded investigators evaluated the location of acetabular labral tears (ALTs), edema at the musculotendinous junction of the iliopsoas insertion, femoral neck anteversion angle, femoral neck shaft angle, acetabular anteversion angle, alpha angle, lateral central edge angle (LCEA), acetabular index, and acetabular depth. Comparison analyses between groups were performed. Twenty-two patients had no ALTs (controls), 19 patients had AALTs, and 35 patients had ALTs not isolated at the 3 o'clock position (25 with cam-bony deformities [FAI-cam] and 10 with pincer-bony deformities [FAI-pincer]). The alpha angle mean was significantly higher (p < 0.001) in the FAI-cam group (62.7 , 95 % confidence interval [CI]: 56.2-69.2 ) compared with the AALTs group (46.9 , 95 % CI: 40.1-53.7 ). The LCEA mean was significantly higher (p < 0.001) in FAI-pincer group (41.9 , 95 % CI: 39.3 -44.5 ) compared to AALTs group (29.4 , 95 % CI: 24.2 -34.6 ). There was no statistically significant difference in any of the bony variables between the controls and the AALTs group. Our study demonstrated that AALTs are pathologically distinct and not associated with FAI or other bony abnormalities. This supports the previous studies, which proposed that AALTs are associated with IPI. (orig.)

MR-arthrography of the acetabular labrum - radiologic-pathologic correlation in 20 cadaveric hip joints; MR-Arthrographie des Labrum acetabulare - Radiologisch-anatomische Korrelation an 20 Leichenhueften

Energy Technology Data Exchange (ETDEWEB)

Brossmann, J.; Steffens, J.C.; Heller, M. [Kiel Univ. (Germany). Klinik fuer Diagnostische Radiologie; Ploetz, G.M.J.; Hassenpflug, J. [Kiel Univ. (Germany). Klinik fuer Orthopadie

1999-08-01

Purpose: To investigate frequency of acetabular labral lesions in elderly hip joints, and to determine sensitivity and specificity of MR arthrography (MRa) for the detection of these abnormalities. Materials and Methods: Twenty cadaveric hip joints were examined by MRa. For MRa, 15 ml of a solution of iodinated contrast solution (Solutrast 300) and Gd-DTPA (100:1) were injected under fluoroscopic guidance. MR imaging was performed on a 1.5 TM scanner (Vision, Siemens; FOV 16 cm, matrix 256x256, fat-suppressed 3D-FLASH). Multiplanar image reconstructions were done perpendicular to the acetabulum in the oblique-coronal, oblique-axial, and radial planes. The labral specimens were examined macroscopically. Results: In 12/20 hips (60%), a labral lesion was found on pathologic examination. In 7 specimens, the labrum was partially or completely detached in the weight-bearing superior region. One flap-like variant of the labrum was seen; in 4 hip joints, the labrum was degenerated (one cystic degeneration). Pathologic findings were confirmed by MRa in 8/12 specimens (sensitivity 67%). All degenerated labra were correctly diagnosed on MRa. Three small labral detachments and the flap-like variant were misinterpreted as being normal. There were no false positive findings (specificity 100%). The accuracy was 80%. Labral lesions were seen in 6/8 and in 6/12 of hips with and without osteoarthritis, respectively. Conclusion: MRa is well suited to delineate the acetabular labrum and to diagnose labral abnormalities. Detection of small labral detachments and anatomic variants is difficult and requires some experience. Labral lesions are correlated to osteoarthritis of the hip, but may be frequently seen in the elderly without underlying osteoarthritis. (orig.) [German] Ziel: Feststellung der Haeufigkeit von Laesionen des Labrum acetabulare bei aelteren Hueftgelenkspraeparaten und Untersuchung der Sensitivitaet und Spezifitaet der MR-Arthrographie (MRa) fuer die Darstellung dieser

MRI morphometric hip comparison analysis of anterior acetabular labral tears

Energy Technology Data Exchange (ETDEWEB)

Aly, Abdel Rahman [University of Saskatchewan, Department of Physical Medicine and Rehabilitation, Saskatoon, SK (Canada); Saskatoon City Hospital, Saskatoon, SK (Canada); Rajasekaran, Sathish [HealthPointe, Pain, Spine and Sport Medicine, Alberta (Canada); Obaid, Haron [Royal University Hospital, University of Saskatchewan, Department of Medical Imaging, Saskatoon, SK (Canada)

2013-09-15

Anterior (3 o'clock) acetabular labral tears (AALTs) have been reported to be associated with iliopsoas impingement (IPI). However, no study has examined the association between anatomical bony variables of the hip joint and AALTs. The purpose of this study was to evaluate the association between AALTs, femoroacetabular impingement (FAI) and other bony variables of the hip. Seventy-six out of 274 hip MRI records met the inclusion criteria. Two independent blinded investigators evaluated the location of acetabular labral tears (ALTs), edema at the musculotendinous junction of the iliopsoas insertion, femoral neck anteversion angle, femoral neck shaft angle, acetabular anteversion angle, alpha angle, lateral central edge angle (LCEA), acetabular index, and acetabular depth. Comparison analyses between groups were performed. Twenty-two patients had no ALTs (controls), 19 patients had AALTs, and 35 patients had ALTs not isolated at the 3 o'clock position (25 with cam-bony deformities [FAI-cam] and 10 with pincer-bony deformities [FAI-pincer]). The alpha angle mean was significantly higher (p < 0.001) in the FAI-cam group (62.7 , 95 % confidence interval [CI]: 56.2-69.2 ) compared with the AALTs group (46.9 , 95 % CI: 40.1-53.7 ). The LCEA mean was significantly higher (p < 0.001) in FAI-pincer group (41.9 , 95 % CI: 39.3 -44.5 ) compared to AALTs group (29.4 , 95 % CI: 24.2 -34.6 ). There was no statistically significant difference in any of the bony variables between the controls and the AALTs group. Our study demonstrated that AALTs are pathologically distinct and not associated with FAI or other bony abnormalities. This supports the previous studies, which proposed that AALTs are associated with IPI. (orig.)

Should money follow the patient: Financial implication for being the National Centre for the Treatment and Management of Pelvic and Acetabular Fractures in Ireland.

LENUS (Irish Health Repository)

Kelly, M E

2013-03-13

BACKGROUND: Pelvic and acetabular fractures are complex injuries requiring specialist treatment. Our institution is the National Centre for Treatment and Management of these injuries. AIM: To audit all referrals to our institution over a 6-month period and calculate the cost incurred by being the national referral centre. METHODS: Retrospective review of database, and subsequent allocation of Casemix points to assess total cost of treatment for each patient referred to our institution. RESULTS: 103 patients referred with pelvic or acetabular fracture for operative management. The furthest referral distance was 181miles. Over-all, the length of stay was 15.4 days. The average inclusive cost for a referral to our unit for operative management was €16,302. CONCLUSION: Pelvic and acetabular fractures are complex injuries that require specialist referral unit management. However for these units to remain sustainable money needs to "follow the patient".

Acetabular roof stress fracture: a rare cause of hip pain in children ...

African Journals Online (AJOL)

Stress fracture of acetabular roof is an unusual cause of hip pain. It is considered as an underdiagnosed entity. People who are more susceptible to experience this fracture are athletes, soldiers and dancers. We present the case of an 11 year old girl with a roof acetabular stress fracture for which the diagnosis and ...

Cement-in-cement acetabular revision with a constrained tripolar component.

Science.gov (United States)

Leonidou, Andreas; Pagkalos, Joseph; Luscombe, Jonathan

2012-02-17

Dislocation of a total hip replacement (THR) is common following total hip arthroplasty (THA). When nonoperative management fails to maintain reduction, revision surgery is considered. The use of constrained acetabular liners has been extensively described. Complete removal of the old cement mantle during revision THA can be challenging and is associated with significant complications. Cement-in-cement revision is an established technique. However, the available clinical and experimental studies focus on femoral stem revision. The purpose of this study was to present a case of cement-in-cement acetabular revision with a constrained component for recurrent dislocations and to investigate the current best evidence for this technique. This article describes the case of a 74-year-old woman who underwent revision of a Charnley THR for recurrent low-energy dislocations. A tripolar constrained acetabular component was cemented over the primary cement mantle following removal of the original liner by reaming, roughening the surface, and thoroughly irrigating and drying the primary cement. Clinical and radiological results were good, with the Oxford Hip Score improving from 11 preoperatively to 24 at 6 months postoperatively. The good short-term results of this case and the current clinical and biomechanical data encourage the use of the cement-in-cement technique for acetabular revision. Careful irrigation, drying, and roughening of the primary surface are necessary. Copyright 2012, SLACK Incorporated.

Pelvic Incidence: A Predictive Factor for Three-Dimensional Acetabular Orientation—A Preliminary Study

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Christophe Boulay

2014-01-01

Full Text Available Acetabular cup orientation (inclination and anteversion is a fundamental topic in orthopaedics and depends on pelvis tilt (positional parameter emphasising the notion of a safe range of pelvis tilt. The hypothesis was that pelvic incidence (morphologic parameter could yield a more accurate and reliable assessment than pelvis tilt. The aim was to find out a predictive equation of acetabular 3D orientation parameters which were determined by pelvic incidence to include in the model. The second aim was to consider the asymmetry between the right and left acetabulae. Twelve pelvic anatomic specimens were measured with an electromagnetic Fastrak system (Polhemus Society providing 3D position of anatomical landmarks to allow measurement of acetabular and pelvic parameters. Acetabulum and pelvis data were correlated by a Spearman matrix. A robust linear regression analysis provided prediction of acetabulum axes. The orientation of each acetabulum could be predicted by the incidence. The incidence is correlated with the morphology of acetabula. The asymmetry of the acetabular roof was correlated with pelvic incidence. This study allowed analysis of relationships of acetabular orientation and pelvic incidence. Pelvic incidence (morphologic parameter could determine the safe range of pelvis tilt (positional parameter for an individual and not a group.

High complication rate in reconstruction of Paprosky type IIIa acetabular defects using an oblong implant with modular side plates and a hook.

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Babis, G C; Sakellariou, V I; Chatziantoniou, A N; Soucacos, P N; Megas, P

2011-12-01

We report the results of 62 hips in 62 patients (17 males, 45 females) with mean age of 62.4 years (37 to 81), who underwent revision of the acetabular component of a total hip replacement due to aseptic loosening between May 2003 and November 2007. All hips had a Paprosky type IIIa acetabular defect. Acetabular revision was undertaken using a Procotyl E cementless oblong implant with modular side plates and a hook combined with impaction allografting. At a mean follow-up of 60.5 months (36 to 94) with no patients lost to follow-up and one died due to unrelated illness, the complication rate was 38.7%. Complications included aseptic loosening (19 hips), deep infection (3 hips), broken hook and side plate (one hip) and a femoral nerve palsy (one hip). Further revision of the acetabular component was required in 18 hips (29.0%) and a further four hips (6.4%) are currently loose and awaiting revision. We observed unacceptably high rates of complication and failure in our group of patients and cannot recommend this implant or technique.

Inguinal Abnormalities in Male Patients with Acetabular Fractures Treated Using an Ilioinguinal Exposure

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Reza Firoozabadi

2015-09-01

Full Text Available Purpose: Surgeons performing an ilioinguinal exposure for acetabular fracture surgery need to be aware of aberrant findings such as inguinal hernias and spermatic cord lesions. The purpose of this study is to report these occurrences in a clinical series of adult males undergoing acetabular fracture fixation and a series of adult male cadavers. The secondary aim is to characterize these abnormalities to aid surgeons in detecting these abnormalities preoperatively and coordinating a surgical plan with a general surgeon.Methods: Clinical study- Retrospective review of treated acetabular fractures through an ilioinguinal approach. Incidence of inguinal canal and spermatic cord abnormalities requiring general surgery consultation were identified. Corresponding CT scans were reviewed and radiographic characteristics of the spermatic cord abnormalities and/or hernias were noted.Cadaveric study- 18 male cadavers dissected bilaterally using an ilioinguinal exposure. The inguinal canal and the contents of the spermatic cord were identified and characterized.Results: Clinical Study- 5.7% (5/87 of patients had spermatic cord lesion and/or inguinal hernia requiring general surgical intervention. Preoperative pelvic CT scan review identified abnormalities noted intraoperatively in four of the five patients. Cord lipomas visualized as enlargements of the spermatic cord with homogeneous density. Hernias visualized as enlarged spermatic cords with heterogeneous density. Cadaver Study- 31% (11/36 of cadavers studied had spermatic cord and/or inguinal canal abnormalities. Average cord diameter in those with abnormalities was 24.9 mm (15-28 compared to 16 mm (11-22 in normal cords, which was statistically significant.Conclusion: The clinical and cadaveric findings emphasize the importance of understanding inguinal abnormalities and the value of detecting them preoperatively. The preoperative pelvic CT scans were highly sensitive in detecting inguinal abnormalities.

[Biomechanical significance of the acetabular roof and its reaction to mechanical injury].

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Domazet, N; Starović, D; Nedeljković, R

1999-01-01

loads. Dimensions and morphological changes in acetabulum showed some but unimportant changes in comparison to that in the control group. These findings are graphically presented in Figure 5 and numerically in Tables 1 and 2. The study of spatial orientation among hip joints revealed that fossa acetabuli was forward and downward laterally directed; this was in accordance with results other authors (1, 7, 9, 15, 18). There was a statistically significant difference in relation to the "eyebrow" size between patients and normal subjects (t = 3.88; p < 0.05). The average difference of "eyebrow" size was 6.892 mm. A larger "eyebrow" was found in patients with normally loaded hip. There was also a significant difference in "eyebrow" size between patients and healthy female subjects (t = 4.605; p < 0.05). A larger "eyebrow" of 8.79 mm was found in female subjects with normally loaded hip. On the basis of our study it can be concluded that the findings related to changes in acetabular roof, the so-called "eyebrow", are important in diagnosis, follow-up and therapy of pathogenetic processes of these disorders.

Ultrasound versus Magnetic Resonance Arthrography in Acetabular Labral Tear Diagnostics: A Prospective Comparison in 20 Dysplastic Hips

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Troelsen, A.; Jacobsen, S.; Bolvig, L.; Gelineck, J.; Roemer, L.; Soeballe, K. [Orthopedic Research Unit and Dept. of Radiology, Univ. Hospital of Aarhus, A arhus (Denmark)

2007-11-15

Background: Acetabular labral tears are highly associated with hip dysplasia. Magnetic resonance arthrography (MR arthrography) is the expensive and time-consuming contemporary gold-standard method in the radiological assessment of acetabular labral tears. Purpose: To assess the diagnostic ability of noninvasive ultrasound (US) examination compared to MR arthrography in diagnosing acetabular labral tears in dysplastic hip joints. Material and Methods: The study compared US examination and MR arthrography diagnosis of labral tears in 20 consecutively referred dysplastic hip joints. Results: The ability to diagnose acetabular labral tears upon US examination was calculated: sensitivity 44%, specificity 75%, positive predictive value 88%, and negative predictive value 25%. Conclusion: The ability of US examination in diagnosing acetabular labral tears is not yet good enough. The technique is still to be developed, and more experience, especially with the interpretation of US examinations, is needed.

Arthroscopic treatment of femoral nerve paresthesia caused by an acetabular paralabral cyst.

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Kanauchi, Taira; Suganuma, Jun; Mochizuki, Ryuta; Uchikawa, Shinichi

2014-05-01

This report describes a rare case of femoral nerve paresthesia caused by an acetabular paralabral cyst of the hip joint. A 68-year-old woman presented with a 6-month history of right hip pain and paresthesia along the anterior thigh and radiating down to the anterior aspect of the knee. Radiography showed osteoarthritis with a narrowed joint space in the right hip joint. Magnetic resonance imaging showed a cyst with low T1- and high T2-weighted signal intensity arising from a labral tear at the anterior aspect of the acetabulum. The cyst was connected to the joint space and displaced the femoral nerve to the anteromedial side. The lesion was diagnosed as an acetabular paralabral cyst causing femoral neuropathy. Because the main symptom was femoral nerve paresthesia and the patient desired a less invasive procedure, arthroscopic labral repair was performed to stop synovial fluid flow to the paralabral cyst that was causing the femoral nerve paresthesia. After surgery, the cyst and femoral nerve paresthesia disappeared. At the 18-month follow-up, the patient had no recurrence. There have been several reports of neurovascular compression caused by the cyst around the hip joint. To the authors' knowledge, only 3 cases of acetabular paralabral cysts causing sciatica have been reported. The current patient appears to represent a rare case of an acetabular paralabral cyst causing femoral nerve paresthesia. The authors suggest that arthroscopic labral repair for an acetabular paralabral cyst causing neuropathy can be an option for patients who desire a less invasive procedure. Copyright 2014, SLACK Incorporated.

Effect of acetabular cup abduction angle on wear of ultrahigh-molecular-weight polyethylene in hip simulator testing.

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Korduba, Laryssa A; Essner, Aaron; Pivec, Robert; Lancin, Perry; Mont, Michael A; Wang, Aiguo; Delanois, Ronald E

2014-10-01

The effect of acetabular component positioning on the wear rates of metal-on-polyethylene articulations has not been extensively studied. Placement of acetabular cups at abduction angles of more than 40° has been noted as a possible reason for early failure caused by increased wear. We conducted a study to evaluate the effects of different acetabular cup abduction angles on polyethylene wear rate, wear area, contact pressure, and contact area. Our in vitro study used a hip joint simulator and finite element analysis to assess the effects of cup orientation at 4 angles (0°, 40°, 50°, 70°) on wear and contact properties. Polyethylene bearings with 28-mm cobalt-chrome femoral heads were cycled in an environment mimicking in vivo joint fluid to determine the volumetric wear rate after 10 million cycles. Contact pressure and contact area for each cup abduction angle were assessed using finite element analysis. Results were correlated with cup abduction angles to determine if there were any differences among the 4 groups. The inverse relationship between volumetric wear rate and acetabular cup inclination angle demonstrated less wear with steeper cup angles. The largest abduction angle (70°) had the lowest contact area, largest contact pressure, and smallest head coverage. Conversely, the smallest abduction angle (0°) had the most wear and most head coverage. Polyethylene wear after total hip arthroplasty is a major cause of osteolysis and aseptic loosening, which may lead to premature implant failure. Several studies have found that high wear rates for cups oriented at steep angles contributed to their failure. Our data demonstrated that larger cup abduction angles were associated with lower, not higher, wear. However, this potentially "protective" effect is likely counteracted by other complications of steep cup angles, including impingement, instability, and edge loading. These factors may be more relevant in explaining why implants fail at a higher rate if

[Effects of Surgically Treated Pelvic Ring and Acetabular Fractures on Postural Control].

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Lang, P; Schnegelberger, A; Riesner, H-J; Stuby, F; Friemert, B; Palm, H-G

2016-04-01

The aim of surgical treatment of pelvic ring and acetabular fractures is to allow rapid mobilisation of patients in order to restore stance and gait stability (postural control), as this significantly correlates with a positive outcome. The regulation of postural stability is mainly controlled by transmission of proprioceptive stimuli. In addition, the pelvis serves as a connection between the legs and the spine and thus is also of great importance for mechanical stabilisation. It remains unclear whether surgical treatment of pelvic ring and acetabular fractures affects the regulation of postural control. Therefore, the aim of this study was to examine the impact of surgically treated pelvic ring and acetabular fractures on postural stability by means of computerised dynamic posturography (CDP) after a mean of 35 months and to compare the results with a healthy control group. A retrospective case control study of 38 patients with surgically treated pelvic ring and acetabular fractures and 38 healthy volunteers was carried out using CDP. The average time of follow-up was 35 (12-78) months. The most important outcome parameter in this investigation was the overall stability index (OSI). Hip joint mobility, the health-related quality of life (SF-12) and pain were supplementary outcome parameters. It was found that surgically treated pelvic ring and acetabular fractures had no influence on postural stability. The OSI was 2.1 ° in the patient group and 1.9 ° in the control group. There was no significant difference between the groups in hip joint mobility. A total of 52 % of patients showed no or only mild pain. Mean health-related quality of life was the same as in the total population. Surgically treated pelvic ring and acetabular fractures do not lead to deterioration in postural control in the mid term. This is of high prognostic importance for rapid mobilisation of the patients. Therefore no increase in the risk of falling is expected after successfully

Measurement of acetabular morphology under three-dimensional reconstruction of CT and significance

International Nuclear Information System (INIS)

Han Yingying; Yang Qiwei; Lai Ying; Hao Shuang; Ma Hecheng; Xiao Chengshuang; Li Youqiong

2011-01-01

Objective: To measure the acetabular morphology of Chinese on CT three-dimensional (3D) reconstruction image, and provide the evidence on the prevention and treatment of hip disease. Methods: 96 cases (192 sides) of adult hip CT scans were reconstructed, the acetabular index (AA), center-edge (CE), ACE angle, anteversion angle (AVA), abduction angle (ABA), and vertical diameter (SID) were measured. Results: The total acetabular index was (8.78±5.34)°, of which male was (7.84±5.55)° and female was (9.60±5.06)°. The total CE was (33.59±5.91)°, of which male was (34.55±6.03)° and female was (32.78±5.70)°. The total ACE angle was (29.01±5.65)°, of which male was (28.02±5.94)° and female was (29.80±5.30)°. The total AVA was (20.92±5.55)°, of which male was (20.48±5.08)° and female was (21.25±5.89)°. The total ABA was (51.27±4.16)°, of which male was (51.71±4.37)° and female was (50.89±3.96)°. The total SID was (53.79±3.92) mm, of which male was (56.55±2.64) mm and female was (51.46±3.25) mm. Of the above data, there were statistical differences in the acetabular index, CE angle, ACE angle and acetabular diameter between men and women (P<0.05), Chinese and foreigners (P<0.05). While there was no statistical difference between the left and right sides (P>0.05). Conclusion: There are differences in acetabular morphology between men and women, Chinese and foreigners. Compared with simply using overseas data, it is better to study morphological parameters of native acetabula to instruct the preoperative preparation and operation of national total hip arthroplasty surgery. And it is meaningful to design national parameters. (authors)

Digestive Fistula Due to Acetabular Protrusion: Case Report and Review of the Literature

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Carlos Marqués

2017-12-01

Full Text Available Intrapelvic migration of the acetabular component after primary or revision hip arthroplasty is a rare complication. We present a case of an intrapelvic migration of the acetabular component after a revision hip arthroplasty which led to an enteric fistula to the hip joint as well as to a sigmoid colon perforation.

Preservation of the Acetabular Cup During Revision Total Hip Arthroplasty Using a Novel Mini-navigation Tool: A Case Report.

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Vincent, John; Alshaygy, Ibrahim; Muir, Jeffrey M; Kuzyk, Paul

2018-01-01

While intraoperative navigation systems have been shown to improve outcomes in primary total hip arthroplasty (THA), their use in the context of revision has been largely overlooked. This case report presents the first documented use of an imageless navigation tool in the context of revision THA, and an unexpected benefit to the surgical procedure as a result. An 84-year-old female patient presented following five episodes of dislocation of the left hip and with pain in the left buttock, groin, and posterior aspect of her hip. Relevant surgical history included primary hip arthroplasty in 1999 and the first revision in 2014. Preoperative analysis revealed a constrained liner that had become disengaged and migrated inferiorly, lodging at the distal aspect of the femoral neck. Acetabular protrusion was also noted. The pre-operative plan included the replacement of the fragmented liner and likely of the acetabular cup due to hardware failure. Intraoperative assessment, however, revealed that the cup was in good condition and would be difficult to remove due to substantial bony ingrowth. With the assistance of imageless navigation, the orientation of the acetabular cup was determined and a new constrained liner was cemented into the preexisting acetabular component at an altered orientation, correcting anteversion by 7°. In revision hip arthroplasty cases, image-based navigation is limited by the presence of existing implants and corresponding metal artefact. This case demonstrates the successful use of an imageless navigation tool for revision surgery. Use of navigation led to the unexpected intraoperative discovery that the acetabular cup was in an acceptable state, and allowed the surgical team to correct the position of the cup using a constrained liner, thus preserving the cup. This significantly benefitted patient outcome, due to the risks associated with the removal of a firmly fixated acetabular cup. While more extensive research is required, this case

Surgical Stabilization of Pelvic and Acetabular Fractures: A Review on the Determinants of Clinical Outcomes

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SS Sathappan

2010-03-01

Full Text Available AIM: Pelvic and acetabular fractures are associated with high-energy trauma. The aim of this study was to identify factors that are associated with specific clinical outcomes following treatment for these fractures. METHODS: A consecutive series of 30 patients who had surgical intervention for either pelvic or acetabular fractures formed the sample for this study. Clinical variables reviewed were: age, associated injuries, number of surgical procedures, time to surgery and post-operative complications. Clinical outcomes were assessed using Matta’s grading of post- operative fracture reduction alignment, and functional outcomes were graded using D'Aubigne & Postel’s Hip scoring system. RESULTS: Study subjects included twelve pelvic fractures and eighteen acetabular fractures. Patients older than 50 years of age had poorer hip scores despite surgery. Earlier fracture fixation (within five days was associated with better hip scores. Patients with acetabular fractures generally had better functional outcomes than patients with pelvic fractures (mean hip score 15.0 vs. 13.5. Closer anatomical reduction of acetabular fractures was associated with better functional outcome. CONCLUSION: Improved clinical outcomes are associated with younger age, fewer concomitant injuries, shorter time interval to surgery and more closely approximated anatomical fracture reduction.

3.0 T conventional hip MR and hip MR arthrography for the acetabular labral tears confirmed by arthroscopy

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Tian, Chun-Yan [Department of Radiology, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing 100191 (China); Wang, Jian-Quan [Department of Sports Medicine, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing 100191,PR China (China); Zheng, Zhuo-Zhao, E-mail: zzhuozhao@aliyun.com [Department of Radiology, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing 100191 (China); Ren, A.-Hong [Department of Radiology, Beijing Daxing Hospital, 26 West Huangcun Road, Daxing District, Beijing 102600 (China)

2014-10-15

Highlights: • MR is the preferred imaging modality for diagnosing acetabular labral tears. • The diagnostic performance of MR arthrography are superior than conventional hip MR. • The hip MR arthrography is recommended for diagnosing acetabular labral lesions. - Abstract: Objective: To evaluate the value of hip MR for diagnosing acetabular labrum tears, and to further compare the diagnostic performances of conventional MR with MR arthrography in acetabular labrum tears. Methods: 90 patients undergoing both hip MR examination and subsequent hip arthroscopy were retrospectively evaluated. Of these patients, 34 accepted both conventional MR and MR arthrography; while the other 56 only underwent conventional MR examination. All hip MR images were independently reviewed by two radiologists, and further compared with the results of hip arthroscopy. Results: 59 of 90 patients were confirmed with acetabular labral tears by hip arthroscopy and 31 without tears. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of conventional MR for evaluating the acetabular labral tears were 61.0%, 77.4%, 83.7% and 51.1% (radiologist A), and 66.1%, 74.2%, 82.9% and 53.4% (radiologist B), respectively, with good consistency between the two observers (K = 0.645). The sensitivity, specificity, PPV and NPV of MR arthrography for assessing the acetabular labral tears were 90.5%, 84.6%, 90.5% and 84.6% (radiologist A), and 95.2%, 84.6%, 90.9% and 91.7% (radiologist B), respectively, with excellent good consistency between the two observers (K = 0.810). The sensitivity and NPV of MR arthrography for diagnosing the acetabular labral tears were significantly higher than those of conventional MR (both P < 0.05). Conclusion: Hip MR arthrography is a reliable evaluation modality for diagnosing the acetabular labral tears, and its diagnostic performance is superior to that of conventional MR at 3.0 T.

Cemented total hip replacement cable debris and acetabular construct durability.

Science.gov (United States)

Altenburg, Aaron J; Callaghan, John J; Yehyawi, Tameem M; Pedersen, Douglas R; Liu, Steve S; Leinen, Jessica A; Dahl, Kevin A; Goetz, Devon D; Brown, Thomas D; Johnston, Richard C

2009-07-01

Third-body wear can adversely affect the outcome of total hip arthroplasty by causing increased polyethylene wear, osteolysis, and component loosening. We hypothesized that there would be greater generation and migration of metal debris to the bearing surfaces in hips in which cobalt-chromium cables were used to reattach the osteotomized greater trochanter when compared with hips in which stainless steel wires were used. Between June 1981 and December 1983, 196 consecutive total hip arthroplasties were performed with use of an Iowa stem and a titanium-backed cemented acetabular component, with cobalt-chromium cable trochanteric reattachment. After nineteen to twenty years of follow-up, the patients were evaluated with regard to the depth of head penetration into the polyethylene (as a surrogate for wear), osteolysis, loosening, and the need for revision. The results were compared with those for a series of 304 total hip arthroplasties that were performed by the same surgeon from January 1984 to December 1985 with use of the same components and the same surgical technique, but with stainless steel wire trochanteric reattachment. The two groups had a comparable nineteen to twenty-year follow-up. All living patients (fifty-nine hips in the cable group and ninety-two hips in the wire group) had minimum ten-year follow-up radiographs. The polyethylene wear rate was 0.101 mm/yr for the cable group and 0.082 mm/yr for the wire group (p = 0.039). For the living patients, the rate of revision of the acetabular component because of aseptic loosening was 37.3% (twenty-two hips) for the cable group and 20.7% (nineteen hips) for the wire group (p = 0.025). The rate of acetabular osteolysis was 44% (twenty-six hips) for the cable group and 26% (twenty-four hips) for the wire group (p = 0.022). Kaplan-Meier analysis with revision of the acetabular component because of aseptic loosening as the end point demonstrated survival rates of 73.7% +/- 9% and 83% +/- 7% for the cable and

[Stress analysis on the acetabular side of bipolar hemiarthroplasty by the two-dimensional finite element method incorporating the boundary friction layer].

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Ichihashi, K; Imura, S; Oomori, H; Gesso, H

1994-11-01

We compared the biomechanical characteristics of bipolar and unipolar hemiarthroplasty on the proximal migration of the outer head by determining the von Mises stress distribution and acetabular (outer head) displacement with clinical assessment of hemiarthroplasty in 75 patients. This analysis used the two-dimensional finite element method, which incorporated boundary friction layers on both the inner and outer bearings of the prosthesis. Acetabular reaming increased stress within the pelvic bone and migration of the outer head. A combination of the acetabular reaming and bone transplantation increased the stress within the pelvic bone and grafted bone, and caused outer head migration. These findings were supported by clinical results. Although the bipolar endoprosthesis was biomechanically superior to the unipolar endoprosthesis, migration of the outer head still occurred. The bipolar endoprosthesis appeared to be indicated in cases of a femoral neck fracture or of avascular necrosis in the femoral head, but its use in cases of osteoarthritis in the hip required caution.

Radiological landmarks for the safe extra-capsular placement of supra-acetabular half pins for external fixation.

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Lidder, Surjit; Heidari, Nima; Gänsslen, Axel; Grechenig, Wolfgang

2013-03-01

Low anterior external fixators are constructed by placing half pins in the dense bone tunnel of the supra-acetabular region in an anterior to posterior direction. Although the placement of these pins is extra-articular, they may still breach the hip capsule on the anterior inferior iliac spine and thus be intra-capsular. We aim to provide radiological markers for the most superior fibres of the capsule to allow safe extra-capsular pin placement within the supra-acetabular bone tunnel. Thirteen cadaveric pelves were used for this study. The supra-acetabular bone tunnel was visualised with an image intensifier. The proximal most fibres of the hip joint capsule were marked with a K-wire so that their relation to the bone tunnel could be clearly seen on the images. Once all images were acquired they were calibrated and analysed to estimate the dimensions of the supra-acetabular bone tunnel and the reflection of the hip capsule. The median height of the bone tunnel was 23.6 mm (18.9-33.2) and maximum width was 11.4 mm (7.6-16.3). The inferior margin of the bone tunnel was 6.7 mm (1.1-14.5) superior to the acetabular dome, and the most proximal fibres of the capsule were 9.3 mm (4.7-6.1) superior to the acetabular dome. The inferior portion of the tunnel was 3.7 mm (0.3-8.9) within the joint. Half pins for the construction of a pelvic external fixator should be placed in the upper half of the supra-acetabular bone corridor to minimise the risk of intra-capsular placement.

Endoscopic resection of acetabular screw tip to decompress sciatic nerve following total hip arthroplasty.

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Yoon, Sun-Jung; Park, Myung-Sik; Matsuda, Dean K; Choi, Yun Ho

2018-06-04

Sciatic nerve injuries following total hip arthroplasty are disabling complications. Although degrees of injury are variable from neuropraxia to neurotmesis, mechanical irritation of sciatic nerve might be occurred by protruding hardware. This case shows endoscopic decompression for protruded acetabular screw irritating sciatic nerve, the techniques described herein may permit broader arthroscopic/endoscopic applications for management of complications after reconstructive hip surgery. An 80-year-old man complained of severe pain and paresthesias following acetabular component revision surgery. Physical findings included right buttock pain with radiating pain to lower extremity. Radiographs and computed tomography imaging showed that the sharp end of protruded screw invaded greater sciatic foramen anterior to posterior and distal to proximal direction at sciatic notch level. A protruding tip of the acetabular screw at the sciatic notch was decompressed by use of techniques gained from experience performing endoscopic sciatic nerve decompression. The pre-operative pain and paresthesias resolved post-operatively after recovering from anesthesia. This case report describes the first documented endoscopic resection of the tip of the acetabular screw irritating sciatic nerve after total hip arthroplasty. If endoscopic resection of an offending acetabular screw can be performed in a safe and minimally invasive manner, one can envision a future expansion of the role of hip arthroscopic surgery in several complications management after total hip arthroplasty.

Minimum ten-year follow-up of acetabular fracture fixation from the Irish tertiary referral centre.

LENUS (Irish Health Repository)

Magill, Paul

2012-04-01

Successful outcome from acetabular fracture fixation is multi-factorial. Long-term results are not frequently reported. Pooling such data from high output centres will help progress acetabular fixation. This paper presents the first ten-year data from the Irish tertiary referral centre.

Acetabular labrum of hip joint in osteoarthritis: A qualitative original study and short review of the literature.

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Kapetanakis, S; Dermon, A; Gkantsinikoudis, N; Kommata, V; Soukakos, P; Dermon, C R

2017-01-01

Histological architecture of normal acetabular labrum regarding free nerve endings (FNEs) and mechanoreceptors (MRs) has been satisfactorily described in the literature. However, the presence of FNEs and MRs in acetabular labrum of hip joint has been analyzed only once in patients with osteoarthritis (OA). Aim of this article is to report histological distribution pattern of FNEs and MRs in acetabular labrum of patients with severe OA, at the same time conducting a comparison with normal acetabular labrum described in the literature. Seven patients with severe hip OA were enrolled in this study. Patient selection was assisted by the utilization of specific clinical scales delineated by the American College of Rheumatology. After successful total hip arthroplasty, tissue samples of acetabular labra of seven patients were histologically processed and stained with the gold standard chloride method, which was subsequently examined under a compound microscope. FNEs and MRs constituted the major histological structures. Identified MRs included Pacini corpuscles, Ruffini corpuscles, and Golgi-Mazzoni corpuscles. The presence of FNEs was predominant in the middle part of the acetabular labrum, featuring a remarkable decrease in peripheral parts. In contrast, MRs were detected basically in peripheral parts and less in the middle part. Differentiation of the distribution pattern of MRs and FNEs in acetabular labrum of hip joint is remarkable between normal patients and patients with severe OA. The abundance of FNEs in the middle part of the pathologic labrum is mainly responsible for the observed discrimination. A "conversion" of MRs to FNEs may occur during OA progression, modulating therefore this pattern as well as the upcoming clinical manifestations.

The Use of a 3D Printer in Pre-operative Planning for a Patient Requiring Acetabular Reconstructive Surgery.

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Duncan, James M; Nahas, Samuel; Akhtar, Kashif; Daurka, Jasvinder

2015-01-01

Surgical management of acetabular fractures is often highly complex, and a successful outcome depends upon an appreciation of the fracture pattern and the most appropriate approach to reduce and hold it. Currently, computed tomography (CT) images are used in conjunction with plain x-rays to identify the main fracture components and their spatial relationship to one another, and as such surgeons still have to make decisions based upon their ability to visualise the fracture from the images available. 3D printers have now become widely available and inexpensive, and can be used to rapidly produce life-size models based on CT scans of an individual patient. The availability of patient specific, accurate and detailed models of complex acetabular fractures can aid planning of surgical management on a patient specific basis. This report describes the use of a 3D printer to create a life-size model reconstruction of the pelvis of a 48 year old male patient who sustained a left sided associated both column acetabular fracture following a motorbike accident in the Sahara Desert. The model allowed visualisation of the multiple fracture fragments and their relative displacements. The tactile feedback allowed assessment of the different fracture fragments. The relative displacement of the quadrilateral plate and posterior column fragments could be assessed and the surgeon felt that these would be amenable to reduction from an ilioinguinal approach. An anatomic reduction was achieved and was held with the application of a pelvic brim plate with 2 screws lagging the posterior column/quadrilateral plate fragment. There are previous examples of 3D models being used in orthopaedic surgery through the use of rapid prototyping, however this method is usually expensive and time consuming. Advances in 3D printer technology offer surgeons a number of advantages when treating these complex fractures. With the ever-increasing economy, ease of use and speed of additive processing, the

Acetabular prosthesis: Proff of migration with ruler and pencil?

International Nuclear Information System (INIS)

Diederichs, C.G.; Fischer, U.; Vosshenrich, R.

1993-01-01

Conventional X-ray films were made with varying degrees of tilt of a pelvic phantom containing an acetabular prosthesis. The position of the prosthesis was then reconstructed graphically. The measurement errors were calculated and an estimate was made for the tilt. There is a linear correlation between the measurement error and the tilt of the prosthesis. Therefore a tilt dependent maximum error can be calculated. This error is very small for small degrees of tilt, so that acetabular migration can in this instance be evaluated with greater confidence than with other graphical methods. The error also correlates with the determination of the selected region of the acetabulum, but not with the position of the central focus spot or image magnification. (orig.) [de

Minimum Lateral Bone Coverage Required for Securing Fixation of Cementless Acetabular Components in Hip Dysplasia

Directory of Open Access Journals (Sweden)

Masanori Fujii

2017-01-01

Full Text Available Objectives. To determine the minimum lateral bone coverage required for securing stable fixation of the porous-coated acetabular components (cups in hip dysplasia. Methods. In total, 215 primary total hip arthroplasties in 199 patients were reviewed. The average follow-up period was 49 months (range: 24–77 months. The lateral bone coverage of the cups was assessed by determining the cup center-edge (cup-CE angle and the bone coverage index (BCI from anteroposterior pelvic radiographs. Further, cup fixation was determined using the modified DeLee and Charnley classification system. Results. All cups were judged to show stable fixation by bone ingrowth. The cup-CE angle was less than 0° in 7 hips (3.3% and the minimum cup-CE angle was −9.2° (BCI: 48.8%. Thin radiolucent lines were observed in 5 hips (2.3%, which were not associated with decreased lateral bone coverage. Loosening, osteolysis, dislocation, or revision was not observed in any of the cases during the follow-up period. Conclusion. A cup-CE angle greater than −10° (BCI > 50% was acceptable for stable bony fixation of the cup. Considering possible errors in manual implantation, we recommend that the cup position be planned such that the cup-CE angle is greater than 0° (BCI > 60%.

3D Printing Aids Acetabular Reconstruction in Complex Revision Hip Arthroplasty

Directory of Open Access Journals (Sweden)

Andrew J. Hughes

2017-01-01

Full Text Available Revision hip arthroplasty requires comprehensive appreciation of abnormal bony anatomy. Advances in radiology and manufacturing technology have made three-dimensional (3D representation of osseous anatomy obtainable, which provide visual and tactile feedback. Such life-size 3D models were manufactured from computed tomography scans of three hip joints in two patients. The first patient had undergone multiple previous hip arthroplasties for bilateral hip infections, resulting in right-sided pelvic discontinuity and a severe left-sided posterosuperior acetabular deficiency. The second patient had a first-stage revision for infection and recurrent dislocations. Specific metal reduction protocols were used to reduce artefact. The images were imported into Materialise MIMICS 14.12®. The models were manufactured using selective laser sintering. Accurate templating was performed preoperatively. Acetabular cup, augment, buttress, and cage sizes were trialled using the models, before being adjusted, and resterilised, enhancing the preoperative decision-making process. Screw trajectory simulation was carried out, reducing the risk of neurovascular injury. With 3D printing technology, complex pelvic deformities were better evaluated and treated with improved precision. Life-size models allowed accurate surgical simulation, thus improving anatomical appreciation and preoperative planning. The accuracy and cost-effectiveness of the technique should prove invaluable as a tool to aid clinical practice.

Improving the accuracy of acetabular cup implantation using a bulls-eye spirit level.

Science.gov (United States)

Macdonald, Duncan; Gupta, Sanjay; Ohly, Nicholas E; Patil, Sanjeev; Meek, R; Mohammed, Aslam

2011-01-01

Acetabular introducers have a built-in inclination of 45 degrees to the handle shaft. With patients in the lateral position, surgeons aim to align the introducer shaft vertical to the floor to implant the acetabulum at 45 degrees. We aimed to determine if a bulls-eye spirit level attached to an introducer improved the accuracy of implantation. A small circular bulls-eye spirit level was attached to the handle of an acetabular introducer. A saw bone hemipelvis was fixed to a horizontal, flat surface. A cement substitute was placed in the acetabulum and subjects were asked to implant a polyethylene cup, aiming to obtain an angle of inclination of 45 degrees. Two attempts were made with the spirit level masked and two with it unmasked. The distance of the air bubble from the spirit level's center was recorded by a single assessor. The angle of inclination of the acetabular component was then calculated. Subjects included both orthopedic consultants and trainees. Twenty-five subjects completed the study. Accuracy of acetabular implantation when using the unmasked spirit level improved significantly in all grades of surgeon. With the spirit level masked, 12 out of 50 attempts were accurate at 45 degrees inclination; 11 out of 50 attempts were "open," with greater than 45 degrees of inclination, and 27 were "closed," with less than 45 degrees. With the spirit level visible, all subjects achieved an inclination angle of exactly 45 degrees. A simple device attached to the handle of an acetabular introducer can significantly improve the accuracy of implantation of a cemented cup into a saw bone pelvis in the lateral position.

Tantalum acetabular augments in one-stage exchange of infected total hip arthroplasty: a case-control study.

Science.gov (United States)

Klatte, Till Orla; Kendoff, Daniel; Sabihi, Reza; Kamath, Atul F; Rueger, Johannes M; Gehrke, Thorsten

2014-07-01

During the one-stage exchange procedure for periprosthetic joint infection (PJI) after total hip arthroplasty (THA), acetabular defects challenge reconstructive options. Porous tantalum augments are an established tool for addressing acetabular destruction in aseptic cases, but their utility in septic exchange is unknown. This retrospective case-control study presents the initial results of tantalum augmentation during one-stage exchange for PJI. Primary endpoints were rates of re-infection and short-term complications associated with this technique. Study patients had no higher risk of re-infection with equivalent durability at early follow-up with a re-infection rate in both groups of 4%. In conclusion, tantalum augments are a viable option for addressing acetabular defects in one-stage exchange for septic THA. Further study is necessary to assess long-term durability when compared to traditional techniques for acetabular reconstruction. Copyright © 2014 Elsevier Inc. All rights reserved.

Posterior trochanteric osteotomy in acetabular fractures for 32 cases.

Science.gov (United States)

Niu, Yunfei; An, Xiaofei; Xu, Shuogui; Wu, Dajiang; Zhang, Chuncai; Li, Ming

2014-11-01

The aim of this study is to explore the method and clinical outcome of posterior trochanteric osteotomy in acetabular fractures. From January 2000 to January 2008, 32 cases of acetabular fractures involving the dome of acetabulum underwent posterior trochanteric osteotomy for a better exposure and internal fixation with acetabular tridimensional memory fixation system. 28 cases (16 men and 12 women, mean age 39.9 years, range 16-73 years) were followed up with an average of 48.9 months (range of 19-95 months) and four were lost during follow up. Of 28 cases, 19 were fresh fractures and 9 were old fractures. The reduction was evaluated with Matta criteria. Clinical evaluation was based on modified Merle d'Aubigne and Postel scoring. Motor strength of the abductors was evaluated according to the Medical Research Council grading system. Ectopic ossification was classified according to Brooker criteria. Anatomical reduction was achieved in 17 cases and satisfied reduction in 10 patients. Poor reduction happened in an old fracture. All acetabular fractures got a direct bone union and no displacement and deep infection occurred. All osteotomies healed within 3.5 months without any nonunion, proximal migration of the greater trochanter, loosing or broken of instrumentation, and deep infection. Two superficial infections were healed with a regular dressing. Two patients underwent removal of implants from greater trochanter because of irritation. The strength of the abductors was of Grade 3/5 in two patients, Grade 4/5 in five patients, and normal in the rest. Clinical scoring was excellent to good in 84 %. Ectopic ossification occurred in five patients, grade 1 in two patients, grade 2 in two, and grade 3 in one. But function of hip joint was not seriously affected. Posterior trochanteric osteotomy can provide an adequate exposure of the dome of acetabulum without the associated complications like nonunion, proximal replacement, and weak of the abductors which often occur

Does Increased Coefficient of Friction of Highly Porous Metal Increase Initial Stability at the Acetabular Interface?

Science.gov (United States)

Goldman, Ashton H; Armstrong, Lucas C; Owen, John R; Wayne, Jennifer S; Jiranek, William A

2016-03-01

Highly porous metal acetabular components illustrate a decreased rate of aseptic loosening in short-term follow-up compared with previous registry data. This study compared the effect of component surface roughness at the bone-implant interface and the quality of the bone on initial pressfit stability. The null hypothesis is that a standard porous coated acetabular cup would show no difference in initial stability as compared with a highly porous acetabular cup when subjected to a bending moment. Second, would bone mineral density (BMD) be a significant variable under these test conditions. In a cadaveric model, acetabular cup micromotion was measured during a 1-time cantilever bending moment applied to 2 generations of pressfit acetabular components. BMD data were also obtained from the femoral necks available for associated specimen. The mean bending moment at 150 μm was not found to be significantly different for Gription (24.6 ± 14.0 N m) cups vs Porocoat (25 ± 10.2 N m; P > .84). The peak bending moment tolerated by Gription cups (33.9 ± 20.3 N m) was not found to be significantly different from Porocoat (33.5 ± 12.2 N m; P > .92). No correlation between BMD and bending moment at 150 μm of displacement could be identified. The coefficient of friction provided by highly porous metal acetabular shells used in this study did not provide better resistance to migration under bending load when compared with a standard porous coated component. Copyright © 2016 Elsevier Inc. All rights reserved.

Acetabular stress fractures in military endurance athletes and recruits: incidence and MRI and scintigraphic findings

International Nuclear Information System (INIS)

Williams, T.R.; Puckett, M.L.; Shin, A.Y.; Gorman, J.D.; Denison, G.

2002-01-01

Objective: To evaluate the incidence and the MRI and scintigraphic appearance of acetabular stress (fatigue) fractures in military endurance athletes and recruits. Design and patients: One hundred and seventy-eight active duty military endurance trainees with a history of activity-related hip pain were evaluated by both MRI and bone scan over a 2-year period. Patients in the study ranged in age from 17 to 45 years. They had hip pain related to activity and had plain radiographs of the hip and pelvis that were interpreted as normal or equivocal. The study was originally designed to evaluate the MRI and scintigraphic appearance of femoral neck stress fractures. Patients had scintigraphy and a limited MRI examination (coronal imaging only) within 48 h of the bone scan. Twelve patients demonstrated imaging findings compatible with acetabular stress fractures. Results: Stress fractures are common in endurance athletes and in military populations; however, stress fracture of the acetabulum is uncommon. Twelve of 178 patients (6.7%) in our study had imaging findings consistent with acetabular stress fractures. Two patterns were identified. Seven of the 12 (58%) patients had acetabular roof stress fractures. In this group, two cases of bilateral acetabular roof stress fractures were identified, one with a synchronous tensile sided femoral neck stress fracture. The remaining five of 12 (42%) patients had anterior column stress fractures, rarely occurring in isolation, and almost always occurring with inferior pubic ramus stress fracture (4 of 5, or 80%). One case of bilateral anterior column stress fractures was identified without additional sites of injury. Conclusions: Stress fractures are commonplace in military populations, especially endurance trainees. Acetabular stress fractures are rare and therefore unrecognized, but do occur and may be a cause for activity-related hip pain in a small percentage of military endurance athletes and recruits. (orig.)

Increased Mortality in Elderly Patients with Sarcopenia and Acetabular Fractures.

Science.gov (United States)

Deren, Matthew E; Babu, Jacob; Cohen, Eric M; Machan, Jason; Born, Christopher T; Hayda, Roman

2017-02-01

Sarcopenia is a condition of clinically relevant loss of muscle mass and function. Acetabular fractures in elderly patients are common and difficult to treat. This study aimed to determine if sarcopenia is common in elderly patients with acetabular fractures and correlates with lower-energy mechanisms of injury, higher rates of complications, and higher mortality than patients with normal muscle mass. The Rhode Island Hospital Trauma Database was queried for patients who were ≥60 years of age from 2005 to 2014 using the International Classification of Diseases, Ninth Revision, code for closed acetabular fracture, 808.0. Charts were retrospectively reviewed for demographic data, operative intervention, mechanism of injury, mortality, comorbidities, and other factors. Computed tomography (CT) was used to determine the muscle cross-sectional area and to calculate the skeletal muscle index. The database revealed 192 patients coded for acetabular fracture; of these, 181 were correctly diagnosed. Ninety-nine patients had recorded body mass index (BMI) and adequate CT scans to measure the skeletal muscle index. Forty-two patients (42.4%) had sarcopenia, and 57 patients (57.6%) did not have sarcopenia. There were no significant differences in demographic characteristics between the groups with the exception of BMI and sex. BMI was higher in patients who did not have sarcopenia (31.7 kg/m) than it was in patients with sarcopenia (23.6 kg/m) (p sarcopenia at 76.2% (32 of 42 patients) than in patients without sarcopenia at 50.9% (29 of 57 patients). Fractures in patients without sarcopenia were associated with a higher-energy mechanism of injury in 78.9% of cases compared with 52.4% of cases of patients with sarcopenia (p = 0.005). Sarcopenia was significantly associated (p = 0.0419) with increased 1-year mortality (28.6%) compared with the absence of sarcopenia (12.3%). This association was even stronger if in-hospital mortality was excluded (p = 0.00074). Finally

Acetabular fractures following rugby tackles: a case series

LENUS (Irish Health Repository)

Good, Daniel W

2011-10-05

Abstract Introduction Rugby is the third most popular team contact sport in the world and is increasing in popularity. In 1995, rugby in Europe turned professional, and with this has come an increased rate of injury. Case presentation In a six-month period from July to December, two open reduction and internal fixations of acetabular fractures were performed in young Caucasian men (16 and 24 years old) who sustained their injuries after rugby tackles. Both of these cases are described as well as the biomechanical factors contributing to the fracture and the recovery. Acetabular fractures of the hip during sport are rare occurrences. Conclusion Our recent experience of two cases over a six-month period creates concern that these high-energy injuries may become more frequent as rugby continues to adopt advanced training regimens. Protective equipment is unlikely to reduce the forces imparted across the hip joint; however, limiting \\'the tackle\\' to only two players may well reduce the likelihood of this life-altering injury.

21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/metal semi-constrained, with a... Devices § 888.3320 Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented acetabular...

21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/metal semi-constrained, with an... Devices § 888.3330 Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with an uncemented acetabular...

Cranial acetabular retroversion is common in developmental dysplasia of the hip as assessed by the weight bearing position

DEFF Research Database (Denmark)

Troelsen, Anders; Mikkelsen, Lone Rømer; Jacobsen, Steffen

2010-01-01

The appearance of acetabular version differs between the supine and weight bearing positions in developmental dysplasia of the hip. Weight bearing radiographic evaluation has been recommended to ensure the best coherence between symptoms, functional appearance, and hip deformities. Previous...... prevalence estimates of acetabular retroversion in dysplastic hips have been established in radiographs recorded with the patient supine and with inclusion only if pelvic tilt met standardized criteria. We assessed the prevalence and the extent of acetabular retroversion in dysplastic hip joints in weight...

Acetabular Reconstruction with the Burch-Schneider Antiprotrusio Cage and Bulk Allografts: Minimum 10-Year Follow-Up Results

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Dario Regis

2014-01-01

Full Text Available Reconstruction of severe pelvic bone loss is a challenging problem in hip revision surgery. Between January 1992 and December 2000, 97 hips with periprosthetic osteolysis underwent acetabular revision using bulk allografts and the Burch-Schneider antiprotrusio cage (APC. Twenty-nine patients (32 implants died for unrelated causes without additional surgery. Sixty-five hips were available for clinical and radiographic assessment at an average follow-up of 14.6 years (range, 10.0 to 18.9 years. There were 16 male and 49 female patients, aged from 29 to 83 (median, 60 years, with Paprosky IIIA (27 cases and IIIB (38 cases acetabular bone defects. Nine cages required rerevision because of infection (3, aseptic loosening (5, and flange breakage (1. The average Harris hip score improved from 33.1 points preoperatively to 75.6 points at follow-up (P<0.001. Radiographically, graft incorporation and cage stability were detected in 48 and 52 hips, respectively. The cumulative survival rates at 18.9 years with removal for any reason or X-ray migration of the cage and aseptic or radiographic loosening as the end points were 80.0% and 84.6%, respectively. The use of the Burch-Schneider APC and massive allografts is an effective technique for the reconstructive treatment of extensive acetabular bone loss with long-lasting survival.

An unusual mode of failure of a tripolar constrained acetabular liner: a case report.

LENUS (Irish Health Repository)

Banks, Louisa N

2012-02-01

Dislocation after primary total hip arthroplasty (THA) is the most commonly encountered complication and is unpleasant for both the patient and the surgeon. Constrained acetabular components can be used to treat or prevent instability after primary total hip arthroplasty. We present the case of a 42-year-old female with a BMI of 41. At 18 months post-primary THA the patient underwent further revision hip surgery after numerous (more than 20) dislocations. She had a tripolar Trident acetabular cup (Stryker-Howmedica-Osteonics, Rutherford, New Jersey) inserted. Shortly afterwards the unusual mode of failure of the constrained acetabular liner was noted from radiographs in that the inner liner had dissociated from the outer. The reinforcing ring remained intact and in place. We believe that the patient\\'s weight, combined with poor abductor musculature caused excessive demand on the device leading to failure at this interface when the patient flexed forward. Constrained acetabular components are useful implants to treat instability but have been shown to have up to 42% long-term failure rates with problems such as dissociated inserts, dissociated constraining rings and dissociated femoral rings being sited. Sometimes they may be the only option left in difficult cases such as illustrated here, but still unfortunately have the capacity to fail in unusual ways.

An unusual mode of failure of a tripolar constrained acetabular liner: a case report.

Science.gov (United States)

Banks, Louisa N; McElwain, John P

2010-04-01

Dislocation after primary total hip arthroplasty (THA) is the most commonly encountered complication and is unpleasant for both the patient and the surgeon. Constrained acetabular components can be used to treat or prevent instability after primary total hip arthroplasty. We present the case of a 42-year-old female with a BMI of 41. At 18 months post-primary THA the patient underwent further revision hip surgery after numerous (more than 20) dislocations. She had a tripolar Trident acetabular cup (Stryker-Howmedica-Osteonics, Rutherford, New Jersey) inserted. Shortly afterwards the unusual mode of failure of the constrained acetabular liner was noted from radiographs in that the inner liner had dissociated from the outer. The reinforcing ring remained intact and in place. We believe that the patient's weight, combined with poor abductor musculature caused excessive demand on the device leading to failure at this interface when the patient flexed forward. Constrained acetabular components are useful implants to treat instability but have been shown to have up to 42% long-term failure rates with problems such as dissociated inserts, dissociated constraining rings and dissociated femoral rings being sited. Sometimes they may be the only option left in difficult cases such as illustrated here, but still unfortunately have the capacity to fail in unusual ways.

Bipolar hip arthroplasty as salvage treatment for loosening of the acetabular cup with significant bone defects

Directory of Open Access Journals (Sweden)

Ghanem, Mohamed

2016-04-01

as subjective pain relief in the majority of patients. We clearly achieved clinically satisfactory results in 14 patients.Conclusion: Bipolar hip arthroplasty is by no means to be regarded as standard procedure in revision surgery of THR. It provides an option or salvage procedure for patients with poor general condition in whom the quickest possible surgical intervention preserving mobility is required. This is particularly true for multi-morbid patients in whom sufficient acetabular fixation is not possible.

Change in Acetabular Cup Orientation From Supine to Standing Position and Its Effect on Wear of Highly Crosslinked Polyethylene.

Science.gov (United States)

Teeter, Matthew G; Goyal, Prateek; Yuan, Xunhua; Howard, James L; Lanting, Brent A

2018-01-01

The purpose of this study is to measure acetabular cup position and wear of the highly crosslinked polyethylene liner in the supine and standing position for patients at a minimum of 10 years after the operation. A total of 38 patients were recruited at a mean of 12.5 years after the operation. All patients received a single acetabular cup design with a highly crosslinked liner and a 28-mm cobalt-chromium femoral head. Patients underwent supine and standing radiostereometric examinations in which the X-ray sources and detectors were positioned to obtain an anterior-posterior and cross-table lateral radiograph. Acetabular cup position and the three-dimensional wear rate were measured from the radiographs, and outcome scores were recorded for each patient. Anteversion significantly increased (P cup orientation and wear rate in either position. Highly crosslinked polyethylene is a forgiving bearing material. Although adherence to the traditional acetabular position target zone is recommended, ensuring hip stability and consideration of the patient's functional position are also important objectives to consider for the acetabular position. Copyright © 2017 Elsevier Inc. All rights reserved.

Femoral anteversion is correlated with acetabular version and coverage in Asian women with anterior and global deficient subgroups of hip dysplasia: a CT study

International Nuclear Information System (INIS)

Akiyama, Mio; Nakashima, Yasuharu; Fujii, Masanori; Sato, Taishi; Yamamoto, Takuaki; Mawatari, Taro; Motomura, Goro; Matsuda, Shuichi; Iwamoto, Yukihide

2012-01-01

Morphological correlation between the acetabulum and femur at the hip joint is still controversial. We tested the hypothesis that femoral anteversion correlates with acetabular version and coverage in patients with developmental dysplasia of the hip (DDH). Using pelvic computed tomography (CT) images of 79 hips in 49 Asian women with DDH and 49 normal hips, we measured femoral anteversion, the axial and vertical acetabular version and the acetabular sector angle (ASA) to demarcate femoral head coverage. Depending on the location of the acetabular bone defect, dysplastic hips were divided into three subgroups: the anterior, global and posterior deficiency groups. We performed a comparative analysis between dysplastic and normal hips using the Wilcoxon rank sum test, and a relative analysis between femoral anteversion and acetabular measurements in dysplastic hips using Pearson's correlation coefficient. The amount of femoral anteversion in dysplastic hips was greater and more variable than in normal hips (p < 0.0001, p = 0.0277 respectively). Femoral anteversion in dysplastic hips correlated significantly with acetabular anteversion in the groups with anterior and global deficiency subgroups (p < 0.05, r = 0.2990, p < 0.05, r = 0.451 respectively), but not with the posterior deficiency subgroup. Femoral anteversion also correlated with vertical acetabular version. When acetabular coverage was examined, significant correlations were noted between femoral anteversion and anterior and superior coverage, but not with posterior coverage. These correlations were not observed in normal hips. Our results showed significantly greater and more variable femoral anteversion in DDH, and a significant correlation between femoral anteversion and acetabular version and coverage in DDH with anterior and global acetabular bone deficiency. (orig.)

Femoral anteversion is correlated with acetabular version and coverage in Asian women with anterior and global deficient subgroups of hip dysplasia: a CT study

Energy Technology Data Exchange (ETDEWEB)

Akiyama, Mio; Nakashima, Yasuharu; Fujii, Masanori; Sato, Taishi; Yamamoto, Takuaki; Mawatari, Taro; Motomura, Goro; Matsuda, Shuichi; Iwamoto, Yukihide [Kyushu University, Department of Orthopaedic Surgery, Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka (Japan)

2012-11-15

Morphological correlation between the acetabulum and femur at the hip joint is still controversial. We tested the hypothesis that femoral anteversion correlates with acetabular version and coverage in patients with developmental dysplasia of the hip (DDH). Using pelvic computed tomography (CT) images of 79 hips in 49 Asian women with DDH and 49 normal hips, we measured femoral anteversion, the axial and vertical acetabular version and the acetabular sector angle (ASA) to demarcate femoral head coverage. Depending on the location of the acetabular bone defect, dysplastic hips were divided into three subgroups: the anterior, global and posterior deficiency groups. We performed a comparative analysis between dysplastic and normal hips using the Wilcoxon rank sum test, and a relative analysis between femoral anteversion and acetabular measurements in dysplastic hips using Pearson's correlation coefficient. The amount of femoral anteversion in dysplastic hips was greater and more variable than in normal hips (p < 0.0001, p = 0.0277 respectively). Femoral anteversion in dysplastic hips correlated significantly with acetabular anteversion in the groups with anterior and global deficiency subgroups (p < 0.05, r = 0.2990, p < 0.05, r = 0.451 respectively), but not with the posterior deficiency subgroup. Femoral anteversion also correlated with vertical acetabular version. When acetabular coverage was examined, significant correlations were noted between femoral anteversion and anterior and superior coverage, but not with posterior coverage. These correlations were not observed in normal hips. Our results showed significantly greater and more variable femoral anteversion in DDH, and a significant correlation between femoral anteversion and acetabular version and coverage in DDH with anterior and global acetabular bone deficiency. (orig.)

Determinación del desgaste del componente acetabular en prótesis totales de cadera. // Wear determination of acetabular component in total hip prosthesis.

Directory of Open Access Journals (Sweden)

G. García del Pino

2002-01-01

Full Text Available En este trabajo se realiza un estudio a través del Método de los Elementos Finitos “MEF” sobre el desgaste del componenteacetabular durante el ciclo de marcha y considerando algunos casos extremos de cargas como subir y bajar escaleras,levantarse de una silla, etc. Utilizando el MEF fueron modelados independientemente los componentes acetabular yfemoral de la prótesis total de cadera y puestos en contacto posteriormente. Fueron estudiadas varias posiciones delacetábulo así como diferentes casos de carga simulando pacientes con diferente peso corporal y actividades físicas. Paraevaluar los resultados se crearon rutinas en lenguaje C que organizaron los mismos para un tratamiento estadísticoposterior.Palabras claves: biomecánica, ortopedia, elementos finitos, modelación, desgaste, prótesis de cadera.___________________________________________________________________________Abstract.A wear study of acetabular component during the marching cycle, considering some extreme loads cases as: ascend anddescend stairways, get up from a seat, etc , by means of Finite Elements Method ( FEM , is carried out. The acetabular andfemoral component of the total hip prosthesis were independently modeled and placed in contact lastly. Several acetabulpositions were studied as well as different load cases, simulating patients with different body weight and different physicalactivities. To evaluate the results routines in C language were created in order to organized the same ones for a laterstatistical treatment.Key words. biomechanics, ortophedy, finite elements, modelation, wear, hip bone prosthesis.

Prophylactic post-operative radiotherapy prevents heterotopic ossification following traumatic acetabular fracture

International Nuclear Information System (INIS)

Meyer, Joseph T.; Hixson, William C.; Jennelle, Richard L. S.; Alonso, Jorge E.; Raben, David; Spencer, Sharon S.; Kim, Robert Y.

1996-01-01

Purpose/Objective: To determine the effect of post-operative radiation on the incidence of heterotopic ossification following traumatic acetabular fracture. Materials and Methods: A retrospective analysis was performed of the medical records and radiographs of all patients who received prophylactic radiotherapy to prevent heterotopic ossification. These results were compared to a similar group of patients receiving no prophylactic radiotherapy following traumatic acetabular fracture. Between 1987 and 1994, sixty-six patients received prophylactic radiotherapy to prevent heterotopic ossification. Results: Thirty-six patients (55%) received radiotherapy following operative repair of a traumatic acetabular fracture (median follow-up: 210 days). Three dose schedules were utilized: (28(36)) (77.8%) received 700 cGy/1 fx, (2(36)) (5.5%) 800 cGy/1 fx, and (6(36)) (16.7%) 1000 cGy/5 fxs. These patients were retrospectively compared with thirty-four patients who received similar operative management of traumatic acetabular fractures without post-operative radiotherapy (median follow-up: 378 days). Of the patients with heterotopic ossification, 96% developed it within 180 days. Complications and delayed wound healing rates were not significantly different in patients treated with or without post-operative radiotherapy, 6.4% and 6.3% respectively (p=0.49). The incidence of heterotopic ossification at last follow-up in patients treated with and without post-operative radiotherapy was (5(36)) (13.9%) and (19(34)) (55.9%), respectively (p=0.000332). For all patients, type of surgical approach was associated with development of heterotopic ossification: posterior, (7(38)) (18.4%), ilio-inguinal (1(3)) (33.3%), tri-radiate (13(19)) (68.4%), p=.000511. In patients receiving post-operative radiotherapy, variables associated with heterotopic ossification included dose (p=.00962), injury-to-radiation interval (p=.0038), and surgery-to-radiation interval (p=.0238). Fifty percent ((3

Acetabular fractures following rugby tackles: a case series

Directory of Open Access Journals (Sweden)

Morris Seamus

2011-10-01

Full Text Available Abstract Introduction Rugby is the third most popular team contact sport in the world and is increasing in popularity. In 1995, rugby in Europe turned professional, and with this has come an increased rate of injury. Case presentation In a six-month period from July to December, two open reduction and internal fixations of acetabular fractures were performed in young Caucasian men (16 and 24 years old who sustained their injuries after rugby tackles. Both of these cases are described as well as the biomechanical factors contributing to the fracture and the recovery. Acetabular fractures of the hip during sport are rare occurrences. Conclusion Our recent experience of two cases over a six-month period creates concern that these high-energy injuries may become more frequent as rugby continues to adopt advanced training regimens. Protective equipment is unlikely to reduce the forces imparted across the hip joint; however, limiting 'the tackle' to only two players may well reduce the likelihood of this life-altering injury.

Evaluation of Medial Acetabular Wall Bone Stock in Patients with Developmental Dysplasia of the Hip Using a Helical Computed Tomography Multiplanar Reconstruction Technique

Energy Technology Data Exchange (ETDEWEB)

Rui Yu Liu; Kun Zheng Wang; Chun Sheng Wang; Xiao Qian Dang; Zhi Qin Tong (Second Hospital Affiliated to the Medical College of Xi' an Jiaotong Univ., Xi' an Shaanxi (China))

2009-08-15

Background: The technique of medialization has been used to reconstruct acetabula at the level of true acetabula in total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH). Appreciation of the bone stock in the medial acetabular wall is significant for making an optimal acetabular reconstruction plan and avoiding complications. Purpose: To evaluate the bone stock of the medial acetabular wall and its relation to the degree of subluxation in patients with DDH using computed tomography (CT). Material and Methods: Helical CT scans of 27 hips were obtained from 21 patients with osteoarthritis secondary to DDH who were scheduled for total hip arthroplasty. Eleven hips belonged to Crowe class I, while 16 hips belonged to Crowe class II/III. The raw CT data were reprocessed in various planes by scrolling multiplanar reformation (MPR). Acetabular opening, depth, and medial bone stock, as indicated by the minimum thickness of the medial acetabular wall, were measured in the transverse reformed MPR plane. Results: The minimum thicknesses of the medial acetabular wall in Crowe-I and Crowe-II/III hips were 3.8+-2.1 mm and 7.1+-3.1 mm, respectively, with statistically significant differences between the groups (P<0.05). Furthermore, the bone stock in the medial acetabular wall correlated with the degree of subluxation (R=0.69) and the acetabular depth (R= ;- ;0.71). Conclusion: There was significantly more bone stock in the medial acetabular wall in patients with higher-degree subluxation than there was in the less-severe class. This difference should be taken into consideration when reconstructing acetabula in THA in patients with DDH using the technique of medialization

Evaluation of Medial Acetabular Wall Bone Stock in Patients with Developmental Dysplasia of the Hip Using a Helical Computed Tomography Multiplanar Reconstruction Technique

International Nuclear Information System (INIS)

Rui Yu Liu; Kun Zheng Wang; Chun Sheng Wang; Xiao Qian Dang; Zhi Qin Tong

2009-01-01

Background: The technique of medialization has been used to reconstruct acetabula at the level of true acetabula in total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH). Appreciation of the bone stock in the medial acetabular wall is significant for making an optimal acetabular reconstruction plan and avoiding complications. Purpose: To evaluate the bone stock of the medial acetabular wall and its relation to the degree of subluxation in patients with DDH using computed tomography (CT). Material and Methods: Helical CT scans of 27 hips were obtained from 21 patients with osteoarthritis secondary to DDH who were scheduled for total hip arthroplasty. Eleven hips belonged to Crowe class I, while 16 hips belonged to Crowe class II/III. The raw CT data were reprocessed in various planes by scrolling multiplanar reformation (MPR). Acetabular opening, depth, and medial bone stock, as indicated by the minimum thickness of the medial acetabular wall, were measured in the transverse reformed MPR plane. Results: The minimum thicknesses of the medial acetabular wall in Crowe-I and Crowe-II/III hips were 3.8±2.1 mm and 7.1±3.1 mm, respectively, with statistically significant differences between the groups (P<0.05). Furthermore, the bone stock in the medial acetabular wall correlated with the degree of subluxation (R=0.69) and the acetabular depth (R= ;- ;0.71). Conclusion: There was significantly more bone stock in the medial acetabular wall in patients with higher-degree subluxation than there was in the less-severe class. This difference should be taken into consideration when reconstructing acetabula in THA in patients with DDH using the technique of medialization

Nonunion of acetabular fractures: evaluation with interactive multiplanar CT

International Nuclear Information System (INIS)

Kuhlman, J.E.; Fishman, E.K.; Ney, D.R.; Brooker, A.F. Jr.; Magid, D.

1989-01-01

Nonunions involving fractures of the acetabulum are reportedly rare, with few citings and little discussion in the literature. It is possible that acetabular nonunions go undetected because imaging of the acetabulum is difficult by conventional radiography. We report two cases of fracture nonunion involving the weight-bearing surface of the acetabulum diagnosed with the aid of computed tomography (CT) and a newly developed interactive 2D/3D orthotool that uniquely processes and reformats routine CT data. The interactive 2D/3D orthotool is a sophisticated computer program that allows dynamic viewing of standard multiplanar reconstructions in the axial, coronal, and sagittal planes as well as multiple oblique projections. The 2D/3D orthotool provides on screen correlation of two-dimensional multiplanar images with three-dimensional reconstructions of the pelvis. The authors found this capability ideally suited for studying fractures with off-axis orientation such as those through the acetabular dome, greatly facilitating the diagnosis of nonunion

A new method for the measurement of anteversion of the acetabular cup after total hip arthroplasty.

Science.gov (United States)

Aydogan, Mehmet; Burç, Halil; Saka, Gursel

2014-08-01

Many methods of determining the anteversion of the acetabular cup have been described in the literature. The advantages and disadvantages of each of these methods are discussed in this paper. We present a new method of measuring the acetabular anteversion at the anteroposterior hip. The formula designed by the authors was anteversion angle (α) = arc sin |PK|/√ |AK| × |BK|. The formula was tested using the AutoCAD software, and an experimental study was conducted to evaluate the accuracy. Three groups were created, and 16 X-ray images were taken and coded. Ten orthopaedic surgeons measured the acetabular anteversion from these X-rays using our formula. The results in Group 1 were closer to the actual value; in contrast, the results in Group 2 differed from the actual values. The results in Group 3 were as close to the actual anteversion values as were those in Group 1. Developments in technology often bring an increase in complications. Despite newly developed surgical methods and technology, the position of the acetabular cup is still used to determine the results of a total hip arthroplasty. Our method is simple, cost-effective and achieves almost 100 % accuracy.

Validation of an optical system to measure acetabular shell deformation in cadavers.

Science.gov (United States)

Dold, Philipp; Bone, Martin C; Flohr, Markus; Preuss, Roman; Joyce, Tom J; Deehan, David; Holland, James

2014-08-01

Deformation of the acetabular shell at the time of surgery can result in poor performance and early failure of the hip replacement. The study aim was to validate an ATOS III Triple Scan optical measurement system against a co-ordinate measuring machine using in vitro testing and to check repeatability under cadaver laboratory conditions. Two sizes of custom-made acetabular shells were deformed using a uniaxial/two-point loading frame and measured at different loads. Roundness measurements were performed using both the ATOS III Triple Scan optical system and a co-ordinate measuring machine and then compared. The repeatability was also tested by measuring shells pre- and post-insertion in a cadaver laboratory multiple times. The in vitro comparison with the co-ordinate measuring machine demonstrated a maximum difference of 5 µm at the rim and 9 µm at the measurement closest to the pole of the shell. Maximum repeatability was below 1 µm for the co-ordinate measuring machine and 3 µm for the ATOS III Triple Scan optical system. Repeatability was comparable between the pre-insertion (below 2 µm) and post-insertion (below 3 µm) measurements in the cadaver laboratory. This study supports the view that the ATOS III Triple Scan optical system fulfils the necessary requirements to accurately measure shell deformation in cadavers. © IMechE 2014.

A new technique for radiographic measurement of acetabular cup orientation.

Science.gov (United States)

Derbyshire, Brian; Diggle, Peter J; Ingham, Christopher J; Macnair, Rory; Wimhurst, James; Jones, Henry Wynn

2014-02-01

Accurate radiographic measurement of acetabular cup orientation is required in order to assess susceptibility to impingement, dislocation, and edge loading wear. In this study, the accuracy and precision of a new radiographic cup orientation measurement system were assessed and compared to those of two commercially available systems. Two types of resurfacing hip prostheses and an uncemented prosthesis were assessed. Radiographic images of each prosthesis were created with the cup set at different, known angles of version and inclination in a measurement jig. The new system was the most accurate and precise and could repeatedly measure version and inclination to within a fraction of a degree. In addition it has a facility to distinguish cup retroversion from anteversion on anteroposterior radiographs. © 2013.

Para-acetabular peritendinitis calcarea; its radiographic manifestations

International Nuclear Information System (INIS)

Kawashima, Akira; Murayama, Sadayuki; Ohuchida, Toshiyuki; Russell, W.J.

1987-02-01

Peritendinitis calcarea and os acetabuli have long been confused during interpretations of hip-joint radiographs. Such confusion is reflected in the medical literature. The present study differentiated these two entities according to their interval radiographic progression and regression. There were 137 instances of para-acetabular calcifications among 110 subjects (59 men and 51 women), whose mean age was 46.8 years at the time of their initial detection. Twenty-six of the subjects had lumbago, which was probably unrelated. Other abnormalities including narrowed intervertebral spaces, scoliosis, and spondylolysis were observed in 21 of the subjects. These could have been responsible for any symptoms they had had, but none of the subjects complained of local hip-joint pain when the radiographs in question were made. Ninety-three of these instances of calcification were reviewed by means of serial radiographs. Interval changes in the sizes and shapes of the calcifications occurred among 90 of them, indicative of the latent type of peritendinitis calcarea. No interval changes were noted in the remaining three cases, indicating they were secondary ossification centers; namely, os acetabuli. This study showed that in asymptomatic adults, most para-acetabular calcifications were really not os acetabuli, but actually peritendinitis calcarea. (author)

The preliminary application of magnetic resonance arthrography in the diagnosis of acetabular labrale tears

International Nuclear Information System (INIS)

Hong Wen; Zhang Xuezhe; Wang Wu; Yue Debo; Wang Weiguo

2010-01-01

Objective: To investigate the application value of MR arthrography (MRA) in the diagnosis of acetabular lab ral tears. Methods: Fifteen patients with a high degree of suspected acetabular lab ral tears received fluoroscope-guided injection of the contrast media into the hip joint (hip arthrography) and fat-saturated spin-echo T 1 -weighted images were obtained in the coronal, sagittal, oblique-axial and radial planes. Hip arthroscopy was performed on 12 of them. Results: Lab ral tears which were diagnosed in 11 patients by hip MRA were confirmed at hip arthroscopy. One patient showed no MRA indication of lab ral tear, also showed normal on arthroscopy. Tear in the anterior-superior quadrant 10 cases of 12 joints (12/13), posterior-superior quadrant 1 case of a joint (1/13). In 11 patients who underwent arthroscopy, hip MRA diagnosed 3 (3/13) joints labrale tears in coronal planes, 10 (10/13) joints in sagittal planes and 13 (13/13) labrale tears in axial-oblique and radial planes. In 15 patients with 20 hip joints, 5 cases 6 joints (6/20) with normal acetabular sublabral sulcus were performed. Conclusions: MR arthrography of hip is a reliable method in the diagnosis of acetabular labrale tears. Scanning method should be included fat-saturated spin-echo T 1 -weighted images in sagittal and oblique-axial planes or sagittal plus radial planes. The diagnosis of torn posterior-inferior quadrant should pay attention to the existence of a normal variation. (authors)

early experience of operative treatment of pelvic and acetabular

African Journals Online (AJOL)

Objective: To review early post-operative results of pelvic and acetabular fracture intern al fixation. Design: ... 600 needing operative treatment annually. ... Infection was controlled with debridement and antibiotics. All the patients in the study returned to their work except one who has yet to do so 5 months after his injury.

Accuracy of templating the acetabular cup size in Total Hip Replacement using conventional acetate templates on digital radiographs.

Science.gov (United States)

Krishnamoorthy, Vignesh P; Perumal, Rajamani; Daniel, Alfred J; Poonnoose, Pradeep M

2015-12-01

Templating of the acetabular cup size in Total Hip Replacement (THR) is normally done using conventional radiographs. As these are being replaced by digital radiographs, it has become essential to create a technique of templating using digital films. We describe a technique that involves templating the digital films using the universally available acetate templates for THR without the use of special software. Preoperative digital radiographs of the pelvis were taken with a 30 mm diameter spherical metal ball strapped over the greater trochanter. Using standard acetate templates provided by the implant company on magnified digital radiographs, the size of the metal ball (X mm) and acetabular cup (Y mm) were determined. The size of the acetabular cup to be implanted was estimated using the formula 30*Y/X. The estimated size was compared with the actual size of the cup used at surgery. Using this technique, it was possible to accurately predict the acetabular cup size in 28/40 (70%) of the hips. When the accuracy to within one size was considered, templating was correct in 90% (36/40). When assessed by two independent observers, there was good intra-observer and inter-observer reliability with intra-class correlation coefficient values greater than 0.8. It was possible to accurately and reliably predict the size of the acetabular cup, using acetate templates on digital films, without any digital templates.

Clinical and Radiological Results over the Medium Term of Isolated Acetabular Revision

Directory of Open Access Journals (Sweden)

Nicola Piolanti

2014-01-01

Full Text Available Acetabular cup loosening is associated with pain, reduced function, and instability of the implant. If such event happens while the femoral implant is in a satisfactory position and is well fixed to the bone, isolated acetabular revision surgery is indicated. The aim of this single-center retrospective study was to evaluate the clinical and radiological results over the medium term (12-month follow-up mean 36, max 60 of isolated acetabular revisions surgery using a porous hemispheric revision shell matched with a cemented all-poly cup and large diameter femoral head (>32. 33 patients were enrolled. We collect any relevant data from the clinical board. Routine clinical and radiographic examinations were performed preoperatively; the postoperative follow-up was made at 1, 3, and 6 months and yearly thereafter. At the last available follow-up, we report satisfactory improvement of functional scores in all the patients; 2 patients (6.1% showed thigh pain and only 4 hips (12.11% presented mild groin pain; all the femoral components are well fixed and there were no potential or pending rerevisions. With bias due to the follow-up and to the retrospective design of the study, we report clinical, functional, and radiological satisfactory results.

Three-dimensional printing model improves morphological understanding in acetabular fracture learning: A multicenter, randomized, controlled study.

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Zhenfei Huang

Full Text Available Conventional education results in unsatisfactory morphological understanding of acetabular fractures due to lack of three-dimensional (3D details and tactile feedback of real fractures. Virtual reality (VR and 3D printing (3DP techniques are widely applied in teaching. The purpose of this study was to identify the effect of physical model (PM, VR and 3DP models in education of morphological understanding of acetabular fractures. 141 students were invited to participate in this study. Participants were equally and randomly assigned to the PM, VR and 3DP learning groups. Three-level objective tests were conducted to evaluate learning, including identifying anatomical landmarks, describing fracture lines, identifying classification, and inferring fracture mechanism. Four subjective questions were asked to evaluate the usability and value of instructional materials. Generally, the 3DP group showed a clear advantage over the PM and VR groups in objective tests, while there was no significant difference between the PM and VR groups. 3DP was considered to be the most valuable learning tool for understanding acetabular fractures. The findings demonstrate that 3DP modelling of real fractures is an effective learning instrument that can be used to understand the morphology of acetabular fractures and promote subjective interest.

Revision of migrated pelvic acetabular components in THA with or without vascular involvement

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Ștefan Cristea

2016-05-01

Full Text Available Purpose. The literature describes a high rate of mortality in cases of intrapelvic acetabular component migration, which is a rare but serious complication. Our aim is to establish and propose a treatment protocol according to our results and experience. Material and Methods. We performed eight (8 total hip revisions with acetabular cup migration between 2006 and 2012. A vascular graft was needed in four (4 of these cases. Two (2 cases were revisions after a spacer for infected arthroplasties. The protocol included the following: X-Ray examination (frontal and lateral views, CT angiography, a biological evaluation, a suitable pre-operative plan, at least six (6 units of blood stock, an experienced anesthesiologist, an experienced surgical team that included a vascular surgeon and a versatile arsenal of revision prostheses, bone grafts and vascular grafts. The anterolateral approach was generally used for hip revisions and the retroperitoneal approach in the dorsal decubitus position was used when vascular risk was involved. Results: The acetabular defect was reconstructed using bone grafts and tantalum revision cups in 4 cases, Burch-Schneider cages in 2 cases, a Kerboull ring in 1 case and a cementless oblong cup (Cotyle Espace in 1 case. In 4 cases, an iliac vessel graft procedure was conducted by the vascular surgeon. All patients survived the revision procedures and returned regularly for subsequent check-ups, during which they did not show any septic complications. Conclusions: Intrapelvic acetabular cup migration is a rare but serious complication that can occur after total hip arthroplasty in either septic or aseptic cases. An experienced, multidisciplinary team of surgeons should be involved in planning and conducting such complicated revisions.

Early Versus Late Weight-Bearing Protocols for Surgically Managed Posterior Wall Acetabular Fractures.

Science.gov (United States)

Heare, Austin; Kramer, Nicholas; Salib, Christopher; Mauffrey, Cyril

2017-07-01

Despite overall improved outcomes with open reduction and internal fixation of acetabular fractures, posterior wall fractures show disproportionately poor results. The effect of weight bearing on outcomes of fracture management has been investigated in many lower extremity fractures, but evidence-based recommendations in posterior wall acetabular fractures are lacking. The authors systematically reviewed the current literature to determine if a difference in outcome exists between early and late postoperative weight-bearing protocols for surgically managed posterior wall acetabular fractures. PubMed and MEDLINE were searched for posterior wall acetabular fracture studies that included weight-bearing protocols and Merle d'Aubigné functional scores. Twelve studies were identified. Each study was classified as either early or late weight bearing. Early weight bearing was defined as full, unrestricted weight bearing at or before 12 weeks postoperatively. Late weight bearing was defined as restricted weight bearing for greater than 12 weeks postoperatively. The 2 categories were then compared by functional score using a 2-tailed t test and by complication rate using chi-square analysis. Six studies (152 fractures) were placed in the early weight-bearing category. Six studies (302 fractures) were placed in the late weight-bearing category. No significant difference in Merle d'Aubigné functional scores was found between the 2 groups. No difference was found regarding heterotopic ossification, avascular necrosis, superficial infections, total infections, or osteoarthritis. This systematic review found no difference in functional outcome scores or complication rates between early and late weight-bearing protocols for surgically treated posterior wall fractures. [Orthopedics. 2017: 40(4):e652-e657.]. Copyright 2017, SLACK Incorporated.

Acetabular bone density and metal ions after metal-on-metal versus metal-on-polyethylene total hip arthroplasty; short-term results

NARCIS (Netherlands)

Zijlstra, Wierd P.; van der Veen, Hugo C.; van den Akker-Scheek, Inge; Zee, Mark J. M.; Bulstra, Sjoerd K.; van Raay, Jos J. A. M.

Information on periprosthetic acetabular bone density is lacking for metal-on-metal total hip arthroplasties. These bearings use cobalt-chromium instead of titanium acetabular components, which could lead to stress shielding and hence periprosthetic bone loss. Cobalt and chromium ions have

The Use of a Supra-Acetabular Antibiotic-Loaded Cement Shelf to Improve Hip Stability in First-Stage Infected Total Hip Arthroplasty.

Science.gov (United States)

Drexler, Michael; Kuzyk, Paul R T; Koo, Kevin; Gross, Allan E; Kosashvili, Yona; Reischl, Nickola; Rutenberg, Tal Frenkel; Safir, Oleg

2016-11-01

Antibiotic-loaded cement spacers in first-stage revision total hip arthroplasty (THA) for managing infection are associated with high dislocation and fracture rates. The aim of this study was to report the use of an antibiotic-loaded cemented supra-acetabular roof augmentation to reinforce hip stability after cement spacer insertion for first-stage total hip revision in the treatment of infected THA. We retrospectively reviewed a consecutive series of 50 THAs involving 47 patients with an infected hip requiring staged revisions of THA. We documented dislocation, reinfection, and time for revision and outcome. There were no cases of hip dislocation, cement fractures, or any other technical complications associated with the use of the roof augmentation lip. Thirteen cases (26%) had a cemented spacer for longer than 120 days. Seven (14%) cases had recurrent infection after staged revision THA. The antibiotic-loaded cemented supra-acetabular roof augment improved femoral head spacer coverage for patients requiring a staged revision THA for infection. Copyright © 2016 Elsevier Inc. All rights reserved.

Entrapment of the acetabular labrum following reduction of traumatic hip dislocation in a child

Energy Technology Data Exchange (ETDEWEB)

Chun, K.A. [The Catholic University of Korea Uijongbu St. Mary' s Hospital, Department of Radiology, Uijongbu, Kyunggi-Do 480-130 (Korea); University of Iowa Hospitals and Clinics, Department of Radiology, Iowa City (United States); Morcuende, J. [University of Iowa Hospitals and Clinics, Department of Orthopaedic Surgery, Iowa City (United States); El-Khoury, G.Y. [University of Iowa Hospitals and Clinics, Department of Radiology, Iowa City (United States)

2004-12-01

In traumatic hip dislocation, concentric reduction can be prevented by various causes. Soft-tissue interposition, such as entrapment of the acetabular labrum, is a rare but important cause of failed reduction of a hip. Early diagnosis of incomplete reduction due to interposition of soft tissue is important, because delayed treatment is associated with a greater incidence of avascular necrosis of the femoral head and early onset of osteoarthritis. This report describes a case of acetabular labral entrapment following reduction of traumatic hip dislocation in a child. The importance of CT and MRI in arriving at an early diagnosis is emphasized. (orig.)

Entrapment of the acetabular labrum following reduction of traumatic hip dislocation in a child

International Nuclear Information System (INIS)

Chun, K.A.; Morcuende, J.; El-Khoury, G.Y.

2004-01-01

In traumatic hip dislocation, concentric reduction can be prevented by various causes. Soft-tissue interposition, such as entrapment of the acetabular labrum, is a rare but important cause of failed reduction of a hip. Early diagnosis of incomplete reduction due to interposition of soft tissue is important, because delayed treatment is associated with a greater incidence of avascular necrosis of the femoral head and early onset of osteoarthritis. This report describes a case of acetabular labral entrapment following reduction of traumatic hip dislocation in a child. The importance of CT and MRI in arriving at an early diagnosis is emphasized. (orig.)

Management of acetabular fractures with modified posterior approach to spare external hip rotators.

Science.gov (United States)

Sarlak, Ahmet Y; Selek, Ozgur; Inanir, Murat; Musaoglu, Resul; Baran, Tuncay

2014-04-01

In the present study the quality of reduction and incidence of complications in hip external rotator sparing modified posterior approach was assessed in both simple and complex acetabular fractures. This retrospective study includes 37 patients (38 hips) with a mean age of 42.1 years (range 21-60), that had been treated for displaced acetabular fractures from June 2007 through May 2011. They were reviewed at a mean of 3 years (20-67 months). The fractures were classified according to the Letournel-Judet classification. Anatomic reduction and stable fixation of the fracture with less than 2mm residual displacement was achieved in 28 of 38 hips. At the final follow up the patients were evaluated clinically according to Merle d'Aubigne and Postel scoring system which had been modified by Matta and radiologically based on the criteria described by Matta. The clinical results were excellent in 20, good in 8, fair in 8, and poor 2 hips. Complications included two superficial local wound infection and 10 heterotopic ossification with 7 of the cases having grade I heterotopic ossification. Avascular necrosis of the femoral head was not seen in any of the 38 hips. One patient with preoperative sciatic nerve palsy had complete recovery of neurologic function. There were no cases of deep vein thrombosis or pulmonary embolism. The functional outcome was satisfactory in most of the cases and comparable with other larger series. Using the limited part of Henry's sciatic nerve exposure skin incision - working in the plane between gluteus maximus and the tensor fascia lata as in the classical Gibson approach and two portal external rotator hip sparing approach resulted in good fracture reduction without approach related complications. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Posterior partial trochanteric osteotomy for the treatment of the roof involved acetabular fractures].

Science.gov (United States)

Wang, Pan-Feng; Xu, Shuo-Gui; Zhang, Chun-Cai; Fu, Qing-Ge; Zhang, Yun-Tong; Liu, Xin-Wei; Niu, Yun-Fei; Tang, Yang

2013-11-01

To introduce a new trochanteric osteotomy,and evaluate the outcome of the procedure combined a posterior lateral approach in treating acetabular fractures which involving the roof. Between March 2007 and Novmber 2010,30 patients with displaced acetabular fractures involving the dome need trochanteric osteotomy were retrospectively reviewed. There were 21 males and 9 females,ranging in age from 18 to 70 years with an average of 35.2 years at the time of injury. According to Letournel-Judet classification, there were 10 posterior wall fractures,7 posterior column fractures,5 transverse fractures, 2 T-shape fractures, 1 transverse associated with posterior wall fracture, 3 posterior column and wall fractures and 2 bicolumn fractures. The standards of Matta,the modified Merle d'Aubigne-Postel, Medical Research Council were respectively used to evaluate the reduction result, function of hip joint and the strength of hip abduction. All patients were followed up with an average time of 25 months (18 to 40) and all osteotomy sites obtained bone union with an average time of 8.4 weeks (6 to 12). No bone non-union, bone block displaceing, internal fixation looseing and breaking,infection of deep part were found. Seventeen patients got anatomic reduction, 12 got satisfied reduction, and 1 got unsatisfied result according to the criteria of Matta. At final follow-up, function of hip joint obtained excellent results in 11 cases, good in 15, fair in 3 and poor in 1. The strength of the abductors of 3 patients were grade 4 and 27 patients were grade 5. Posterior partial great trochanteric osteotomy can enhance the exposure and provide a more accurate reduction and degrade the difficulty of acetabular fracture fixation without increasing the risk of complications. The method provide a new way for the treatment of the roof involved acetabular fractures.

The role of trochanteric flip osteotomy in fixation of certain acetabular fractures

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Sandeep Gupta

2017-06-01

Conclusion: Trochanteric flip osteotomy is a very effective technique to fix certain acetabular fractures especially those with dome involvement. It is more accurate and associated with no significant complications compared with conventional way.

Reliability of ultrasonographic measurements in suspected patients of developmental dysplasia of the hip and correlation with the acetabular index

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Cem Copuroglu

2011-01-01

Full Text Available Background: Ultrasonography is accepted as a useful imaging modality in the early detection of developmental dysplasia of the hip (DDH. Early detection and early treatment of DDH prevents hip dislocation and related physical, social, economic, and psychological problems. The purpose of this study was to evaluate the reliability of ultrasonographic and roentgenographic measurements measured by seven different observers. Materials and Methods: The alpha angles of 66 hips in 33 patients were measured using the Graf method by seven different observers. Acetabular index degrees on plane roentgenograms were measured in order to assess the correlation between the ultrasonographic alpha angle and the radiographic acetabular index, which both show the bony acetabular depth, retrospectively. Results: The interclass correlation coefficient, measuring the interobserver reliability, was high and statistically significant for the ultrasonographic measurements. There was a negative correlation between the alpha angle and the acetabular index. Conclusions: Ultrasonography, when applied properly, is a reliable technique between different observers, in the diagnosis and follow up of DDH. When assessed concomitantly with the roentgenographic measurements, the results are reliable and statistically meaningful.

Acetabular cup position and risk of dislocation in primary total hip arthroplasty

DEFF Research Database (Denmark)

Seagrave, Kurt G; Troelsen, Anders; Malchau, Henrik

2017-01-01

Background and purpose - Hip dislocation is one of the most common complications following total hip arthroplasty (THA). Several factors that affect dislocation have been identified, including acetabular cup positioning. Optimal values for cup inclination and anteversion are debatable. We performed...... a systematic review to describe the different methods for measuring cup placement, target zones for cup positioning, and the association between cup positioning and dislocation following primary THA. Methods - A systematic search of literature in the PubMed database was performed (January and February 2016......) to identify articles that compared acetabular cup positioning and the risk of dislocation. Surgical approach and methods for measurement of cup angles were also considered. Results - 28 articles were determined to be relevant to our research question. Some articles demonstrated that cup positioning influenced...

Cam deformity and acetabular dysplasia as risk factors for hip osteoarthritis

NARCIS (Netherlands)

Hosnijeh, Fatemeh Saberi; Zuiderwijk, Maria E; Versteeg, Mathijs; Smeele, Hieronymus T W; Hofman, Albert; Uitterlinden, André G; Agricola, Rintje; Oei, Edwin H G; Waarsing, Jan H; Bierma-Zeinstra, Sita M; van Meurs, Joyce B J

2017-01-01

Objective: Cam deformity and acetabular dysplasia have been recognized as relevant risk factors for hip osteoarthritis (OA) in a few prospective studies with limited sample sizes. To date, however, no evidence is available from prospective studies regarding whether the magnitude of these

Femoro-acetabular impingement and hip pain with conventionally normal x-rays.

LENUS (Irish Health Repository)

Baker, J F

2010-06-01

There has in recent years been a fundamental change in the understanding of hip pain in the young adult and hip pain without plain radiographic findings of arthritis. Pain in these groups has long represented a diagnostic and therapeutic challenge. With new appreciation of hip biomechanics, pathological processes and the arrival of modern imaging modalities we now have a greater understanding of non-arthritic hip pathology. One of the commonest yet least well recognized \\'new\\' diagnoses around the hip is femoro-acetabular impingement (FAI). FAI is a developmental condition of the hip joint that is associated with abnormal anatomical configuration and thus joint mechanics on either the femoral or acetabular sides or both. It is hypothesized to have a variety of precipitants and may ultimately lead to labral and chondral injury and what has previously been referred to as \\'primary\\' or \\'idiopathic\\' hip osteoarthritis.

Bilateral non-traumatic acetabular and femoral neck fractures due to pregnancy-associated osteoporosis.

Science.gov (United States)

Aynaci, Osman; Kerimoglu, Servet; Ozturk, Cagatay; Saracoglu, Metehan

2008-03-01

Pregnancy-associated osteoporosis is a rare disorder and its pathophysiology remains unknown. We report a case of pregnancy-associated osteoporosis in a 27-year-old primiparous patient who revealed bilateral hip pain during early postnatal period. The plain radiographs and computerized tomography showed bilateral femoral neck and acetabular fractures. The diagnosis of osteoporosis was established by bone mineral density. Diagnostic work-up excluded a secondary osteoporosis. The case was treated successfully by bilateral cementless total hip arthroplasty. Bone mineral density increased after 2 years of treatment with calcium-vitamin D, calcitriol and alendronate. Diagnosis of pregnancy-associated osteoporosis should be suspected when hip pain occurs during pregnancy or in the post-partum period as it can lead to acetabular and femoral neck fractures.

Ipsilateral Traumatic Posterior Hip Dislocation, Posterior Wall and Transverse Acetabular Fracture with Trochanteric Fracture in an adult: Report of First Case

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Skand Sinha

2013-10-01

Full Text Available Introduction: Posterior dislocation of the hip joint with associated acetabular and intertrochanteric fracture is a complex injury. Early recognition, prompt and stable reduction is needed of successful outcome. Case Report: 45 year old male patient presented with posterior dislocation of the hip with transverse fracture with posterior wall fracture of acetabulam and intertrochanteric fracture on the ipsilateral side. The complex fracture geometry was confirmed by CT scan. The patient was successfully managed by open reduction and internal fixation of intertrochanteric fracture was achieved with dynamic hip screw (DHS plate fixation followed by fixation of acetabular fracture with reconstruction plate. Conclusion: Hip dislocation combined with acetabular fracture is an uncommon injury; this article presents a unique case of posterior wall and transverse fractures of ipsilateral acetabulum with intertrochanteric fracture in a patient who sustained traumatic posterior hip dislocation. Early surgical intervention is important for satisfactory outcomes of such complex fracture-dislocation injuries. Keywords: Hip dislocation; acetabular fractures; intertrochanteric fracture; operative treatment.

The diagnostic accuracy of acetabular labral tears using magnetic resonance imaging and magnetic resonance arthrography: a meta-analysis

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Smith, Toby O. [University of East Anglia, Faculty of Health, Queen' s Building, Norwich (United Kingdom); Hilton, Gemma [Norfolk and Norwich University Hospital, Norwich (United Kingdom); Toms, Andoni P.; Donell, Simon T. [Norfolk and Norwich University Hospital, University of East Anglia, Norwich (United Kingdom); Hing, Caroline B. [St. George' s Hospital, London (United Kingdom)

2011-04-15

Magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) have been advocated for the diagnosis of acetabular labral tears. The purpose of this study was to determine the sensitivity and specificity of MRI and MRA in diagnosing acetabular labral tears using meta-analysis. Pertinent published and unpublished literature databases were reviewed. A two-by-two table was constructed to calculate the sensitivity and specificity of MRI or MRA investigations against surgical outcomes. Pooled sensitivity and specificity and Receiver Operating Characteristic curve (ROC) evaluations were performed. Methodological quality of each study was assessed using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies) tool. Nineteen papers assessing 881 hips were reviewed. Conventional MRI was assessed in 13 studies and MRA was assessed in 16 studies. Whilst both MRI (0.5-3T) and MRA (0.5-3T) presented with a moderate sensitivity and specificity (sensitivity 66%, 87%; specificity 79%, 64%), diagnostic accuracy of MRA appeared to be superior to MRI in detecting acetabular labral tears on ROC curve interpretation. The literature poorly described population characteristics, assessor blinding, with limited sample sizes. MRI and MRA may be useful adjuncts in the diagnosis of acetabular labral tears in adults. MRA appears to be superior to conventional MRI. (orig.)

Efficient radiologic diagnosis of pelvic and acetabular trauma

International Nuclear Information System (INIS)

Kreitner, K.F.; Mildenberger, P.; Thelen, M.; Rommens, P.M.

2000-01-01

In spite of the widespread availability of CT scanners, conventional X-ray radiographs remain the basic imaging modality in patients with pelvic and/or acetabular trauma. However, the extent of their use will depend on local utilities (e.g., availability of CT scanners) and on the patient's clinical condition. Regarding the inaccuracy of conventional radiography in the diagnosis of injuries of the dorsal pelvic ring and of the acetabulum, computed tomography represents the most important imaging modality in the clinically stable patient. CT provides an exact staging of the extent of trauma and allows for differentiation of pelvic instabilities. CT clearly demonstrates the severity of acetabular trauma and is superior in the detection of local complicating factors, i.e., impressions fractures and (sub-)luxations of the femoral head as well as free intraarticular fragments. CT findings provide the basis for definite treatment regimens of the injured patient. By extension of the examination, all relevant organs and systems (craniospinal, cardiovascular, gastrointestinal, respiratory, genitourinary) can be imaged during one session. The speed of spiral CT scanners and their diagnostic accuracy will play a major role in the management of, especially, polytraumatized patients. The indication for angiography with the option of therapeutic embolization exists if a pelvic bleeding persists even after reposition and operative fixation of the injury. (orig.) [de

Reduced survival for uncemented compared to cemented total hip arthroplasty after operatively treated acetabular fractures.

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Clarke-Jenssen, John; Westberg, Marianne; Røise, Olav; Storeggen, Stein Arne Øvre; Bere, Tone; Silberg, Ingunn; Madsen, Jan Erik

2017-11-01

Post traumatic arthritis and avascular necrosis of the femoral head are common complications after operatively treated acetabular fractures. This may cause severe disabilities for the patient, necessitating a total hip arthroplasty. Even though an arthroplasty may provide good symptomatic relief, the long-term results are more uncertain and no consensus exists according to preferred prosthetic designs. With this cohort study, we aimed to investigate the medium to long term arthroplasty survival and clinical results of total hip arthroplasty after operatively treated acetabular fractures. We included 52 patients treated with a secondary total hip arthroplasty at a median of 2.4 (0.1-14.1) years after an operatively treated acetabular fracture. The median age was 54 (11-82) years. Cemented arthroplasty was used for 33 patients, 10 patients had an uncemented arthroplasty and 9 patients received a hybrid arthroplasty. Average follow up was 8.0 (SD 5.0) years. Ten-year revision free arthroplasty survival was 79%. Uncemented arthroplasties had a significantly worse 10-year survival of 57%. Arthroplasties performed at a centre without a pelvic fracture service also had a significantly worse 10-years survival of 51%. Cox regression showed similar results with an 8-fold increase in risk of revision for both uncemented arthroplasties and operations performed at a non-pelvic trauma centre. Total hip arthroplasty secondary to an operatively treated acetabular fracture provides good symptomatic relief. These patients are, however, complex cases and are probably best treated at specialist centres with both pelvic trauma surgeons and arthroplasty surgeons proficient in complex revisions present. Copyright © 2017 Elsevier Ltd. All rights reserved.

Absence or interruption of the supra-acetabular line: a subtle plain film indicator of hip pathology

International Nuclear Information System (INIS)

Major, N.M.; Helms, C.A.

1996-01-01

Objective. To show that absence or interruption of the supraacetabular line is a subtle plain film indicator of pathology in the acetabulum. Design. Nineteen hips from 17 patients with known disease processes involving the acetabulum as demonstrated by subsequent magnetic resonance imaging, bone scan or plain film follow-up were evaluated with antero-posterior (AP) plain films of the pelvis. Three additional cases were diagnosed prospectively using interruption of the supra-acetabular line as the criterion for inclusion. Fifty AP plain films of the pelvis in patients without hip pain were examined prospectively to determine normal imaging criteria. Results and conclusions. The normal supra-acetabular line measures 2-3 mm in thickness superiorly and is a thin sclerotic line in the medial aspect. In all 22 hips (with pathology) in this series, the line was interrupted or absent. Loss or interruption of the supra-acetabular line may thus be a subtle pain film indicator of a disease process involving the acetabulum. This plain film sign has not previously been reported. (orig.). With 8 figs., 1 tab

Rapid Hip Osteoarthritis Development in a Patient with Anterior Acetabular Cyst with Sagittal Alignment Change

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Yasuhiro Homma

2014-01-01

Full Text Available Rapidly destructive coxarthrosis (RDC is rare and develops unusual clinical course. Recent studies suggest multiple possible mechanisms of the development of RDC. However the exact mechanism of RDC is still not clear. The difficulty of the study on RDC is attributed to its rareness and the fact that the data before the onset of RDC is normally unavailable. In this report, we presented the patient having the radiographic data before the onset who had rapid osteoarthritis (OA development after contralateral THA, which meets the current criteria of RDC. We thought that the increased posterior tilt of the pelvis after THA reinforced the stress concentration at pre-existed anterior acetabular cyst, thereby the destruction of the cyst was occurred. As a result the rapid OA was developed. We think that there is the case of rapid osteoarthritis developing due to alternating load concentration by posterior pelvic tilt on preexisting anterior acetabular cyst such as our patient among the cases diagnosed as RDC without any identifiable etiology. The recognition of sagittal alignment changes and anterior acetabular cyst may play important role in prediction and prevention of the rapid hip osteoarthritis development similar to RDC.

Acetabular osteotomy for double boarding in lateral decubitus. Anatomical bases and surgical technique

International Nuclear Information System (INIS)

Lazennec, J Y; Del Vecchio, R; Saillant, G

2001-01-01

The periacetabular osteotomies of reorientation of the eotilo have a reputation of being difficult from the technical point of view. The authors present a technique of juxta acetabular osteotomy that respects the posterior column of the acetabulo the same as the GANZ technique. The osteotomy is of simpler realization thanks to an installation that allows carrying out two simultaneous boarding. The osteotomy lines, their rectilinear and controllable in permanency through of images intensificator and they don't constitute any risk for the essential vascular contribution of the obturatriz artery and their branches. Their other interest comes represented by the possibility of correcting easily the parasitic retroversion associated to the descent of the whole eotilo, that it allows to avoid the bad positions that they affect the center of the articulation and the widths acetabular

Should total hip arthroplasty be performed acutely in the treatment of acetabular fractures in elderly or used as a salvage procedure only?

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Katharine Hamlin

2017-01-01

Full Text Available Background: Total hip arthroplasty (THA is now an increasingly common procedure for people sustaining acetabular fractures. The incidence of acetabular fractures among the elderly population is increasing, and contemporary treatment aims to avoid the risks of prolonged incumbency associated with poor bone stock for fixation or inability to comply with limited weightbearing in this patient group. The concept of acute hip arthroplasty as a treatment for acetabular fracture is, therefore, becoming more topical and relevant. Our systematic review investigates whether THAs for acetabular fractures should be performed acutely, with a short delay, or as a late procedure for posttraumatic osteoarthritis (PTOA if it develops. Materials and Methods: Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed when undertaking this systematic review. Detailed searches were performed on three different databases, using keywords, such as “acetabular fracture,” “acetabular trauma,” “total hip arthroplasty,” “hip arthroplasty,” and “hip prosthesis.” Studies from 1975 to September 2016 were included in the study. All studies included in the review were independently critically appraised by two of the authors. Results: Forty three studies were included in this review. Only two of them actually compared acute and delayed THAs for acetabular fractures with the rest focusing on one or the other. Results were comparable between acute and late THAs in terms of aseptic loosening, operative time, blood loss, Harris Hip Score, and ability to mobilize postoperatively without aid. Complication rates, however, were much higher in the acute group. Conclusion: Evidence based on this topic is scarce and therefore we have to be cautious about drawing a definitive conclusion. The findings of this systematic review do suggest, however, that acute THAs should be considered in elderly patients, where fixation is not possible, or

Primary stability of a cementless acetabular cup in a cohort of patient-specific finite element models.

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O'Rourke, Dermot; Al-Dirini, Rami Ma; Taylor, Mark

2018-03-01

The primary stability achieved during total hip arthroplasty determines the long-term success of cementless acetabular cups. Pre-clinical finite element testing of cups typically use a model of a single patient and assume the results can be extrapolated to the general population. This study explored the variability in predicted primary stability of a Pinnacle ® cementless acetabular cup in 103 patient-specific finite element models of the hemipelvis and examined the association between patient-related factors and the observed variability. Cups were inserted by displacement-control into the FE models and then a loading configuration simulating a complete level gait cycle was applied. The cohort showed a range of polar gap of 284-1112 μm and 95th percentile composite peak micromotion (CPM) of 18-624 μm. Regression analysis was not conclusive on the relationship between patient-related factors and primary stability. No relationship was found between polar gap and micromotion. However, when the patient-related factors were categorised into quartile groups, trends suggested higher polar gaps occurred in subjects with small and shallow acetabular geometries and cup motion during gait was affected most by low elastic modulus and high bodyweight. The variation in primary stability in the cohort for an acetabular cup with a proven clinical track record may provide benchmark data when evaluating new cup designs. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1012-1023, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Revisión acetabular con conservación del componente metálico osteointegrado y cementado de un componente de poliestireno. Reporte de una serie de 40 casos. [Acetabular revision cementing a liner into a stable acetabular shell

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Fernando Manuel Bidolegui

2013-12-01

Full Text Available In­tro­duc­ción: Un escenario cada vez más frecuente en la cirugía de revisión protésica de la cadera es hallar un cotilo no cementado fijo con una falla del componente modular de polietileno. Una completa revisión acetabular se presenta como demasiado agresiva cuando el componente metálico es salvable. Cementar un nuevo inserto de polietileno dentro del componente acetabular metálico os-teointegrado es una alternativa. Comunicamos los resultados con esta técnica, y sus indicaciones, el modo de realización y las posibles limitaciones. Materiales­y­Métodos: Entre 2001 y 2011, se cementaron 40 componentes de polietileno dentro de copas no cementadas. Se evaluó radiológicamente y clínicamente a todos los pacientes. El motivo por el que se cementó un inserto fue falla o rotura de mecanismo de captura (11 casos; 27,5%, ganar estabilidad (18 casos; 45% y falta de disponibilidad del inserto correspondiente (11 casos, 27,5%. Resultados:­ La tasa de duración del implante sin reoperación a 46 meses de seguimiento fue del 92%. Un paciente (2,4% sufrió una infección, y dos presentaron inestabilidad (4,8%. No se presentaron aflojamientos hasta el último seguimiento. El puntaje preoperatorio y posoperatorio en la escala de Harris fue de 59 y 80, respectivamente. Conclusiones: Los datos técnicos por considerar para tener éxito son: utilizar un inserto de menor tamaño que el de la copa, cementar insertos texturizados y dejar siempre como mínimo un manto de cemento uniforme de 2 mm. Nuestros resultados preliminares cementando un inserto de polietileno dentro de una copa acetabular osteointegrada parecerían justificar esta técnica de revisión en pos de prevenir la pérdida de capital óseo asociada a la necesidad de recambio de copas osteointegradas.

Copas de metal trabecular y aloinjertos óseos impactados en defectos acetabulares graves. Resultados a los 2-4 años. [Impacted bone allografts and trabecular metal cups in severe acetabular bone defects: 2 to 4-year results.

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Martín Buttaro

2014-06-01

Full Text Available In­tro­duc­ción: El objetivo principal es presentar la supervivencia del componente acetabular en pacientes con defectos graves reconstruidos con copas de metal trabecular combinadas con aloinjertos óseos impactados. Como objetivo secundario, se compararon estos resultados con los previamente obtenidos por los autores en defectos de similar gravedad utilizando anillos de reconstrucción y aloinjertos óseos. Materiales­ y­ Métodos:­ Se realizaron 20 cirugías de revisión en 19 pacientes (edad promedio 65 años, controlados, de forma prospectiva, con defectos acetabulares graves tipos 3A o 3B de Paprosky, por falla mecánica o infecciosa. El puntaje funcional promedio preoperatorio fue de 6,2 puntos, según la escala de Merle D ́Aubigne. Siempre se utilizaron copas de metal trabecular y aloinjertos óseos impactados. Resultados:­ A los 30 meses de seguimiento promedio (rango 24-48 meses, la supervivencia del componente acetabular fue del 95% (IC = 75%-98%. Un paciente presentó un aflojamiento acetabular por infección profunda a las 16 semanas de la revisión y fue tratado con una artroplastia de resección. El puntaje funcional promedio, excluido el caso con aflojamiento posoperatorio, fue de 16,2 puntos. Se observó la incorporación de los aloinjertos óseos en todos los pacientes, salvo el caso con infección profunda. La comparación con nuestras series históricas reconstruidas con anillos de Kerboull o con anillos GAP arrojó resultados altamente favorables a favor de las copas de metal trabecular.  Conclusiones: Las copas de metal trabecular asociadas a aloinjertos óseos impactados ofrecen una alternativa válida en cirugía de revisión acetabular con defectos graves del capital óseo. Este método se asocia a resultados más favorables que los obtenidos antes con anillos de reconstrucción.

Human bone ingrowth into a porous tantalum acetabular cup

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Gregory N. Haidemenopoulos

2017-11-01

Full Text Available Porous Tantalum is increasingly used as a structural scaffold in orthopaedic applications. Information on the mechanisms of human bone ingrowth into trabecular metal implants is rather limited. In this work we have studied, qualitatively, human bone ingrowth into a retrieved porous tantalum monoblock acetabular cup using optical microscopy, scanning electron microscopy and energy dispersive X-ray analysis. According to the results and taking into account the short operational life (4 years of the implant, bone ingrowth on the acetabular cup took place in the first two-rows of porous tantalum cells to an estimated depth of 1.5 to 2 mm. The bone material, grown inside the first raw of cells, had almost identical composition with the attached bone on the cup surface, as verified by the same Ca:P ratio. Bone ingrowth has been a gradual process starting with Ca deposition on the tantalum struts, followed by bone formation into the tantalum cells, with gradual densification of the bone tissue into hydroxyapatite. A critical step in this process has been the attachment of bone material to the tantalum struts following the topology of the porous tantalum scaffold. These results provide insight to the human bone ingrowth process into porous tantalum implants.

The crescent sign: dissociation of the polyethylene liner from a modular acetabular component in total hip arthroplasty

International Nuclear Information System (INIS)

White, S.P.; Blom, A.W.; Lee, M.; Smith, E.J.

2005-01-01

To study whether there was a common pattern of clinical symptoms, signs and radiographic features for the dissociation of the polyethylene liner from an acetabular component and to postulate reasons for these features. Retrospective study of notes and radiographs of cases of revision hip arthroplasty for polyethylene liner dissociation of the cementless Harris-Galante I porous-coated acetabular component (Zimmer Inc, Warsaw, IN) at the Avon Orthopaedic Centre, Bristol, UK and St. Mary's Hospital, Bristol, UK between 1995 and 2004. Patients were contacted to confirm preoperative symptoms. Nine cases of late polyethylene liner dissociation of this prosthesis have been revised in these institutions. All patients presented with a reduction in mobility, groin pain and limp. Eight patients reported an audible noise on hip movement. In all cases, radiographs showed radiolucency medial to the femoral neck in association with an eccentrically placed femoral head showing contact with the acetabular metal shell, which we have termed the ''crescent sign.'' There is a typical clinical presentation in this study. The diagnosis can be made from a single anteroposterior pelvic radiograph without the need for previous films for comparison, or the need for arthrography. Clinicians should look specifically for the crescent sign when an eccentrically placed femoral head has been noted, in order to differentiate the more unusual diagnosis of dissociation from that of polyethylene wear. Early revision surgery can prevent damage to the femoral head and metal acetabular shell, thus reducing the complexity of revision surgery. (orig.)

Difficult acetabular revision. A preliminary report.

Science.gov (United States)

Newport, M L; Stuchin, S A; Frankel, V H; Zuckerman, J

1986-01-01

Thirteen patients (14 hips) underwent revision from conventional cemented total hip arthroplasty to uncemented acetabular threaded screw-in components and cementless femoral press-fit stems by means of the Autophor, Biofit, and Ti-Thread designs. The patients suffered from all forms of primary hip disease except rheumatoid arthritis; their average age was 34 years. The average preoperative Harris hip score was 39.4; the average postoperative score was 71.2 at six months, 90.6 at one year, and 91.6 at two years. Complications included two femoral shaft fractures, one femoral nerve palsy, and one dislocation. No signs have been observed of loosening or migration as of an early (6-24 months) follow-up.

A pilot trial comparing the tear-out behavior in screw-sockets and cemented polyethylene acetabular components - a cadaveric study.

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Möbius, R; Schleifenbaum, S; Grunert, R; Löffler, S; Werner, M; Prietzel, T; Hammer, N

2016-10-01

The removal of well-fixed acetabular components following THA (total hip arthroplasty) is a difficult operation and could be accompanied by the loss of acetabular bone stock. The optimal method for fixation is still under debate. The aim of this pilot study was to compare the tear-out resistance and failure behavior between osseo-integrated and non-integrated screw cups. Furthermore, we examined whether there are differences in the properties mentioned between screw sockets and cemented polyethylene cups. Tear-out resistance and related mechanical work required for the tear-out of osseo-integrated screw sockets are higher than in non-integrated screw sockets. Ten human coxal bones from six cadavers with osseo-integrated screw sockets (n=4), non-integrated (implanted post-mortem, n=3) screw sockets and cemented polyethylene cups (n=3) were used for tear-out testing. The parameters axial failure load and mechanical work for tear-out were introduced as measures for determining the stability of acetabular components following THA. The osseo-integrated screw sockets yielded slightly higher tear-out resistance (1.61±0.26kN) and related mechanical work compared to the non-integrated screw sockets (1.23±0.39kN, P=0.4). The cemented polyethylene cups yielded the lowest tear-out resistance with a failure load of 1.18±0.24kN. Compared to the screw cups implanted while alive, they also differ on a non-significant level (P=0.1). Osseous failure patterns differed especially for the screw sockets compared to the cemented polyethylene cups. Osseo-integration did not greatly influence the tear-out stability in cementless screw sockets following axial loading. Furthermore, the strength of the bone-implant-interface of cementless screw sockets appears to be similar to cemented polyethylene cups. However, given the high failure load, high mechanical load and because of the related bone failure patterns, removal should not be performed by means of tear-out but rather by osteotomes

Morphological experimental study of bone stress at the interface acetabular bone/prosthetic cup in the bipolar hip prosthesis.

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Anuşca, D; Pleşea, I E; Iliescu, N; Tomescu, P; Poenaru, F; Dascălu, V; Pop, O T

2006-01-01

By calculating the tension and distortion of the elements composing the bipolar prosthesis under extreme conditions encountered in real life using a special post-processing program, we established the variation curves of the contact pressure at the hip bone-cup, armor-cup and cup-femoral head interface. By comparing the data obtained from all the examined cases, important conclusions were drawn regarding the influence of tension and pressure distribution on the structural integrity and biomechanics of the prosthesis, as well as the acetabular wear and tear, in order to assess its reliability. The experimentally determined tension and distortion status at the acetabular bone-metal armour interface, lead to the wear and tear phenomenon, which can be explained by three mechanisms and theories incompletely reflecting the overall process. The histopathologic study of the acetabular bone tissue using FEM (finite elements method) on surgically removed specimens will probably lead to the identification of a series of factors that could reduce the rate of the wear and tear process.

Acetabular QCT in Total Hip Arthroplasty - a reliability study using porcine hips

DEFF Research Database (Denmark)

Mussmann, Bo Redder; Overgaard, Soren; Torfing, Trine

and reliability of bone mineral density measurements (BMD) in close proximity of the acetabular cup using SECT and DECT images and 3D segmentation software. Materials and methods 22 acetabular cups (12 cemented, 10 un-cemented) were inserted in porcine hip specimens ex vivo. A femoral stem was attached to each...... difference between the double measurements in SECT was 8 mg/cm3 (p=0.64) and 2 mg/cm3 in DECT (p=0.6). In the cemented concept the differences were 33 mg/cm3 (p=0.054) and 11 mg/cm3 (p=0.014), respectively. ICC was >0.90 regardless of scan mode and cup type. In both cup types the Bland-Altman limits...... of agreement were wider in SECT (uncemented: -95 to 111; cemented: -86 to 153) compared with DECT (uncemented: -28 to 23; cemented: -21 to 44). Conclusion There were no statistically significant reliability differences between SECT and DECT, but results suggest that the agreement of DECT is better than...

Wear analysis by applying a pin-disc configuration to phemoral head and acetabular cup

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Guillermo Urriolagoitia-Calderón

2008-01-01

Full Text Available This work determines a prosthetic hip system’s life-span, focusing on a Mexican phenotype. The total sliding equivalent distance for the system was determined, as well as the loading regime under which the femoral component and the acetabular cup were subjected in normal operating conditions. An experimental tribology essay was then performed to simulate the wearing of the components in a Pin over Disc machine. This assay (for which the test specimens were manufactured in medical grade stainless steel AISI-ASTM 316L for the femoral component and high density polyethylene for the acetabular cup was aimed at simulating wear conditions involved in 10 years of continuous operation. A numerical simulation of operational conditions (using the finite element method was performedIn for establishing assay loading conditions to accurately determine where the loads should be applied. The tribology assay led to quantifying the volumetric loss of materials for the system being analysed. It can be concluded that the methodology proposed in this work for estimating the life-span of a prosthetic hip system was valid and accurate by comparing the results with those found in the literature. A statistical validation of the proposed method is plaaned for the future. Key words: Design life; femoral component; acetabular cup; Mexican phenotype; pin-disc configuration.

Use of iPhone technology in improving acetabular component position in total hip arthroplasty

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Xiau Wei Tay, MBBS

2017-09-01

Full Text Available Improper acetabular cup positioning is associated with high risk of complications after total hip arthroplasty. The aim of our study is to objectively compare 3 methods, namely (1 free hand, (2 alignment jig (Sputnik, and (3 iPhone application to identify an easy, reproducible, and accurate method in improving acetabular cup placement. We designed a simple setup and carried out a simple experiment (see Method section. Using statistical analysis, the difference in inclination angles using iPhone application compared with the freehand method was found to be statistically significant (F[2,51] = 4.17, P = .02 in the “untrained group”. There is no statistical significance detected for the other groups. This suggests a potential role for iPhone applications in junior surgeons in overcoming the steep learning curve.

Lumbosacral plexopathies associated with acetabular fracture

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Patpiya Sirasaporn

2017-01-01

Full Text Available Lumbosacral plexopathies are of considerably less epidemiologic common prevalence than brachial plexus. The most common form of trauma resulting in lesions affecting the lumbosacral plexus is injuries to sacroiliac region. The symptoms which are caused by compressing lumbosacral plexus are sensory disturbance and weakness in an affected leg. The author reports a case of a 65-year-old male with a history of right acetabular fracture status post open reduction and internal fixation by plate and screw who complained weakness and numbness in the right leg. Four months later, he still had difficulty in walking and felt paresthesia at the right lateral thigh and entire of the right foot. His further investigation which was electrodiagnostic study was diagnosed as right lumbosacral plexopathies.

Examination and treatment of a professional ballet dancer with a suspected acetabular labral tear: A case report.

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Khoo-Summers, Lynnette; Bloom, Nancy J

2015-08-01

Dancers are at risk for developing groin pain that is due to acetabular labral tears. Although surgical management of labral tears has been reported extensively, conservative management has been poorly described. This case report describes the examination, diagnosis, and treatment of groin pain in a professional ballet dancer with a suspected acetabular labral tear. Treatment focused on decreasing anterior hip joint stresses and improving the precision of hip motion through correction of alignment and movement impairments noted during functional activities and dance. Successful outcomes included a reduction in pain and return to professional ballet dancing. Copyright © 2015 Elsevier Ltd. All rights reserved.

Acetabular labral tears with underlying chondromalacia: a possible association with high-level running.

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Guanche, Carlos A; Sikka, Robby S

2005-05-01

The use of hip arthroscopy has helped delineate intra-articular pathology and has enabled clinicians to further elucidate the factors responsible for injuries, such as running. The subtle development of degenerative changes may be a result of repetitive impact loading associated with this sport. This study presents a population of runners with common pathologic acetabular changes. Case series. Eight high-level runners with an average age of 36 years (range, 19 to 45 years) were seen for complaints of increasing hip pain with running without any history of macrotrauma. All of the patients had either run several marathons (4), were triathletes (1), Olympic middle distance runners (1), or had run more than 10 miles per week for longer than 5 years (2). Plain radiographic analysis revealed no degenerative changes and an average center-edge (CE) angle of 36.7 degrees (range, 28 degrees to 44 degrees). All patients underwent hip arthroscopy with labral debridement. In 6 patients (75%), a chondral injury of the acetabular cartilage underlying the labral tear was noted. In addition, 3 patients had ligamentum teres disruptions. It is possible that the development of these tears is the result of subtle instability, which may be exacerbated by running, eventually leading to labral tearing and possible ligamentum teres disruption. While perhaps concurrently, subtle acetabular dysplasia may play a role. Although this study does not confirm an association between running and the development of labral tears or chondral lesions in the hip, it certainly questions whether there is an injury pattern common to this population, a "runner's hip." Level IV.

Combination acetabular radiofrequency ablation and cementoplasty using a navigational radiofrequency ablation device and ultrahigh viscosity cement: technical note.

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Wallace, Adam N; Huang, Ambrose J; Vaswani, Devin; Chang, Randy O; Jennings, Jack W

2016-03-01

Percutaneous radiofrequency ablation and cementoplasty is an alternative palliative therapy for painful metastases involving axial load-bearing bones. This technical report describes the use of a navigational radiofrequency probe to ablate acetabular metastases from an anterior approach followed by instillation of ultrahigh viscosity cement under CT-fluoroscopic guidance. The tumor ablation databases of two institutions were retrospectively reviewed to identify patients who underwent combination acetabular radiofrequency ablation and cementoplasty using the STAR Tumor Ablation and StabiliT Vertebral Augmentation Systems (DFINE; San Jose, CA). Pre-procedure acetabular tumor volume was measured on cross-sectional imaging. Pre- and post-procedure pain scores were measured using the Numeric Rating Scale (10-point scale) and compared. Partial pain improvement was categorically defined as ≥ 2-point pain score reduction. Patients were evaluated for evidence of immediate complications. Electronic medical records were reviewed for evidence of delayed complications. During the study period, 12 patients with acetabular metastases were treated. The median tumor volume was 54.3 mL (range, 28.3-109.8 mL). Pre- and post-procedure pain scores were obtained from 92% (11/12) of the cohort. The median pre-procedure pain score was 8 (range, 3-10). Post-procedure pain scores were obtained 7 days (82%; 9/11), 11 days (9.1%; 1/11) or 21 days (9.1%; 1/11) after treatment. The median post-treatment pain score was 3 (range, 1-8), a statistically significant difference compared with pre-treatment (P = 0.002). Categorically, 73% (8/11) of patients reported partial pain relief after treatment. No immediate symptomatic complications occurred. Three patients (25%; 3/12) were discharged to hospice within 1 week of treatment. No delayed complications occurred in the remaining 75% (9/12) of patients during median clinical follow-up of 62 days (range, 14-178 days). Palliative percutaneous

Biomechanical analysis of the fixation systems for anterior column and posterior hemi-transverse acetabular fractures.

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Lei, Jianyin; Dong, Pengfei; Li, Zhiqiang; Zhu, Feng; Wang, Zhihua; Cai, Xianhua

2017-05-01

The aim of this study was to evaluate the biomechanical properties of common fixation systems for complex acetabular fractures. A finite element (FE) pelvic model with anterior column and posterior hemi-transverse acetabular fractures was created. Three common fixation systems were used to fix the posterior wall acetabular fractures: 1. Anterior column plate combined with posterior column screws (group I), 2. Anterior column plate combined with quadrilateral area screws (group II) and 3. Double-column plates (group III). And 600 N, representing the body weight, was loaded on the upper surface of the sacrum to simulate the double-limb stance. The amounts of total and relative displacements were compared between the groups. The total amount of displacement was 2.76 mm in group II, 2.81 mm in group III, and 2.83 mm in group I. The amount of relative displacement was 0.0078 mm in group II, 0.0093 mm in group III and 0.014 mm in group I. Our results suggested that all fixation systems enhance biomechanical stability significantly. Anterior column plate combined with quadrilateral area screws has quite comparable results to double column plates, they were superior to anterior column plate combined with posterior screws. Copyright © 2017 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

Importance of preoperative imaging in acetabular revision surgery - a case report.

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Schmitz, Hc; Egidy, Cc; Al-Khateeb, H; Cárdenas, G; Gehrke, T; Kendoff, D

2012-01-01

Acetabular defects, particularly as a result of protrusion of acetabular components into the hemipelvis, may cause serious complications during revision procedures as a result of iatrogenic injury to surrounding anatomical structures. In these challenging cases, we advocate the utilisation of preoperative three dimensional imaging. MRI and CT- imaging offer superior understanding of the three-dimensional quality of bony defects and the relationship of implants to important anatomical structures. Appropriate preoperative planning may also prevent major complications during the removal of the pre-existing hardware, prior to re-implantation of implants. Potential complications include injury of nerves, blood vessels and other intrapelvic structures.In our case, a major bony defect of the acetabulum was a result of the protrusion of an implanted reinforcement ring. A preoperative, contrast-enhanced CT scan showed that the urethra was in close proximity to the hook of the reinforcement ring.The preoperative imaging aided in identifying and understanding the potential complications that could occur intraoperatively. Additionally, it delineated the intact anatomic structures prior to surgery, which could have medico-legal implications.The importance of preoperative imaging and the existing literature is discussed within this case description.

The role of trochanteric flip osteotomy in fixation of certain acetabular fractures.

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Gupta, Sandeep; Singh, Jagdeep; Virk, Jagandeep Singh

2017-06-01

Complete visualization of certain acetabular fractures of posterior wall or column with cranial extension involving superior dome from standard surgical exposures is a challenge. Osteotomy of the greater trochanter has been used to enhance fracture visualization, especially the dome, in posterior and lateral exposures of the acetabulum. It also decreases the need for excessive muscle retraction. The purpose of the study was to investigate the outcome associated with trochanteric flip osteotomy in the management of certain acetabulum fractures. From January 2011 to December 2013, 25 displaced acetabular fractures were treated by open reduction and internal fixation. The fractures were managed using a Kocher-Langenbeck approach along with trochanteric flip osteotomy. At 3rd, 6th and 24th month follow-up, all patients had radiographic examination and underwent a final clinical evaluation based on the modified Merle d'Aubigne and Postel score. The strength of the abductors was assessed according to the Medical Research Council (MRC) grading system. Congruent reduction was achieved in all patients and all osteotomies healed within an average period of 3.8 months. All our patients were allowed full weight bearing at the end of 3 months and with no abductor lurch at the end of 6 months follow-up. There were no cases of avascular necrosis of femoral head. None of the patients had any neurovascular complication or infection by the end of the follow-up period. Trochanteric flip osteotomy is a very effective technique to fix certain acetabular fractures especially those with dome involvement. It is more accurate and associated with no significant complications compared with conventional way. Copyright © 2017 Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. Production and hosting by Elsevier B.V. All rights reserved.

Positive effect of removal of subchondral bone plate for cemented acetabular component fixation in total hip arthroplasty: a randomised RSA study with ten-year follow-up.

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Flivik, G; Kristiansson, I; Ryd, L

2015-01-01

We hypothesised that the removal of the subchondral bone plate (SCBP) for cemented acetabular component fixation in total hip arthroplasty (THA) offers advantages over retention by improving the cement-bone interface, without jeopardising implant stability. We have previously published two-year follow-up data of a randomised controlled trial (RCT), in which 50 patients with primary osteoarthritis were randomised to either retention or removal of the SCBP. The mean age of the retention group (n = 25, 13 males) was 70.0 years (sd 6.8). The mean age in the removal group (n = 25, 16 males) was 70.3 years (sd 7.9). Now we have followed up the patients at six (retention group, n = 21; removal group, n = 20) and ten years (retention group: n = 17, removal group: n = 18), administering clinical outcome questionnaires and radiostereometric analysis (RSA), and determining the presence of radiolucent lines (RLLs) on conventional radiographs. RSA demonstrated similar translation and rotation patterns up to six years. Between six and ten years, proximal acetabular component migration and changes of inclination were larger in the retention group, although the mean differences did not reach statistical significance. Differences in migration were driven by two patients in the SCBP retention group with extensive migration versus none in the SCBP removal group. The significant difference (p < 0.001) in the development of radiolucent lines in the retention group, previously observed at two years, increased even further during the course of follow-up (p < 0.001). While recognising SCBP removal is a more demanding technique, we conclude that, wherever possible, the SCBP should be removed to improve the cement-bone interface in order to maximise acetabular component stability and longevity. ©2015 The British Editorial Society of Bone & Joint Surgery.

The development and nature of femoral head cam lesions following acetabular fractures.

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Berber, Onur; Foote, Julian; Sabharwal, Sanjeeve; Datta, Gorav; Bircher, Martin D

2014-01-01

The aim of acetabular fracture fixation is to restore joint congruity with restoration of the articular surface. Poor outcomes are seen where this has not been achieved. Letournel reported a collarette osteophyte seen postoperatively in a proportion of patients, which he suggested was an early precursor to the development of osteoarthritis. This is a retrospective study of patients treated at a tertiary referral unit who developed this lesion. The triangular index was measured in 48 of these patients and then correlated with their clinical findings, Oxford Hip Score and the presence of osteoarthritis. Length of follow-up, fracture classification, and joint congruency were also recorded. Results showed a statistically significant relationship between cam lesion size and the development of osteoarthritis (P = 0.008), cam lesion size and length of follow-up (P = 0.01), and between groin pain and postoperative joint congruency (LR = 0.035). These findings suggest that the appearance of a cam lesion is a poor long-term prognostic marker for the development of osteoarthritis in patients with an acetabular fracture.

3D CT versus axial helical CT versus conventional tomography in the classification of acetabular fractures: A ROC analysis

International Nuclear Information System (INIS)

Kickuth, Ralph; Laufer, Ulf; Hartung, Guido; Gruening, Christian; Stueckle, Christoph; Kirchner, Johannes

2002-01-01

AIM: To assess the diagnostic power of three-dimensional computed tomography (3D CT), axial helical computed tomography (CT) and conventional tomography in the classification of acetabular fractures by interdisciplinary review. MATERIALS AND METHODS: Receiver operating characteristics (ROCs) were assessed for two radiologists and two surgeons blinded to the presence of acetabular fractures in an animal model (a total of 62 porcine hips, 40 of them with artificial acetabular fractures). Main target parameter was the diagnostic accuracy in the classification of the artificial fractures following Judet et al. RESULTS: ROC analysis for radiologists showed A z values of 0·83 for 3D CT, 0·81 for axial helical CT, and 0·78 for conventional tomography; differences between the three techniques were not significant (P = 0·46-0·73). A z values for the surgeons were 0·87 for 3D CT, 0·68 for axial helical CT, and 0·60 for conventional tomography; 3D CT was significantly better than axial helical CT (P = 0·01) and conventional tomography (P = 0·001). The differences between axial helical CT and conventional tomography were not significant (P = 0·37). CONCLUSION: Acetabular fractures are best classified by 3D CT, followed by axial helical CT and conventional tomography when assessed by surgeons. 3D CT did not provide any additional significant benefit in the classification performed by radiologists. Kickuth, R. et al. (2002)

Abordagem cirúrgica inédita para denervação acetabular em cães A new surgical approach to acetabular denervation in dogs

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Cássio R.A. Ferrigno

2007-02-01

Full Text Available Este artigo tem por objetivo demonstrar nova abordagem cirúrgica para denervação seletiva das fibras sensitivas do periósteo acetabular, para tratamento da displasia coxo femoral em cães, conduzidas em 189 articulações. Para tanto, é descrita abordagem da região cranial e dorso-lateral do acetábulo de cães por incisão em forma de meia lua de aproximadamente de três centímetros de extensão, iniciando trocânter maior do fêmur e em direção ao corpo do ílio. Após rebatimento dorsal do músculo glúteo médio, secciona-se parcialmente a inserção do m. glúteo profundo para acesso às regiões citadas. Com auxílio de cureta foi removido, em todos os pacientes, periósteo na margem acetabular cranial e dorso lateral, até a exposição da cortical óssea. Em todos os animais foi possível a abordagem, tanto da face cranial como também acesso para a curetagem da face dorsal do acetábulo, com a técnica descrita, com incisão de pele de aproximadamente 3,2cm. A curetagem da porção cranial do acetábulo foi, em todos os casos realizados, sem visualização do osso, mas de fácil confecção e sem intercorrências de lesão de nervos ou músculos. Em todas as abordagens foi possível visualizar a cápsula articular da articulação coxo femoral, e em nenhum dos animais esta estrutura foi incisada por erro de técnica. Conclui-se que a abordagem cirúrgica descrita no presente trabalho é factível para este tipo de procedimento cirúrgico em cães, promovendo acesso adequado, com mínima invasão e sem complicações de qualquer natureza.The purpose of this study is to demonstrate a new surgical approach for the selective denervation of the sensitive fibers of the acetabular periosteum, for the treatment of hip dysplasia in dogs, conducted in 189 joints.The surgical approach of the cranial and dorso-lateral regions of the acetabular joint in dogs, by moon-shaped incision of approximately 3cm in extension, starting from the

Open reduction and internal fixation of osteoporotic acetabular fractures through the ilio-inguinal approach: use of buttress plates to control medial displacement of the quadrilateral surface.

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Peter, Robin E

2015-01-01

The number of acetabular fractures in the geriatric population requiring open reduction and internal fixation is increasing. Fractures with medial or anterior displacement are the most frequent types, and via the ilio-inguinal approach buttress plates have proved helpful to maintain the quadrilateral surface or medial acetabular wall. Seven to ten hole 3.5 mm reconstruction plates may be used as buttress plates, placed underneath the usual pelvic brim plate. This retrospective study presents our results with this technique in 13 patients at a minimum follow-up of 12 months (average, 31 months). 85% of the patients had a good result. The early onset of post-traumatic osteoarthritis necessitated total hip arthroplasty in two patients (15%) at 12 and 18 months follow-up, respectively. This treatment option should be considered in the surgeon's armamentarium when fixing these challenging cases. Copyright © 2015 Elsevier Ltd. All rights reserved.

Single-stage Acetabular Revision During Two-stage THA Revision for Infection is Effective in Selected Patients.

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Fink, Bernd; Schlumberger, Michael; Oremek, Damian

2017-08-01

The treatment of periprosthetic infections of hip arthroplasties typically involves use of either a single- or two-stage (with implantation of a temporary spacer) revision surgery. In patients with severe acetabular bone deficiencies, either already present or after component removal, spacers cannot be safely implanted. In such hips where it is impossible to use spacers and yet a two-stage revision of the prosthetic stem is recommended, we have combined a two-stage revision of the stem with a single revision of the cup. To our knowledge, this approach has not been reported before. (1) What proportion of patients treated with single-stage acetabular reconstruction as part of a two-stage revision for an infected THA remain free from infection at 2 or more years? (2) What are the Harris hip scores after the first stage and at 2 years or more after the definitive reimplantation? Between June 2009 and June 2014, we treated all patients undergoing surgical treatment for an infected THA using a single-stage acetabular revision as part of a two-stage THA exchange if the acetabular defect classification was Paprosky Types 2B, 2C, 3A, 3B, or pelvic discontinuity and a two-stage procedure was preferred for the femur. The procedure included removal of all components, joint débridement, definitive acetabular reconstruction (with a cage to bridge the defect, and a cemented socket), and a temporary cemented femoral component at the first stage; the second stage consisted of repeat joint and femoral débridement and exchange of the femoral component to a cementless device. During the period noted, 35 patients met those definitions and were treated with this approach. No patients were lost to followup before 2 years; mean followup was 42 months (range, 24-84 months). The clinical evaluation was performed with the Harris hip scores and resolution of infection was assessed by the absence of clinical signs of infection and a C-reactive protein level less than 10 mg/L. All

Acetabular component positioning in total hip arthroplasty with and without a computer-assisted system: a prospective, randomized and controlled study.

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Gurgel, Henrique M C; Croci, Alberto T; Cabrita, Henrique A B A; Vicente, José Ricardo N; Leonhardt, Marcos C; Rodrigues, João Carlos

2014-01-01

In a study of the acetabular component in total hip arthroplasty, 20 hips were operated on using imageless navigation and 20 hips were operated on using the conventional method. The correct position of the acetabular component was evaluated with computed tomography, measuring the operative anteversion and the operative inclination and determining the cases inside Lewinnek's safe zone. The results were similar in all the analyses: a mean anteversion of 17.4° in the navigated group and 14.5° in the control group (P=.215); a mean inclination of 41.7° and 42.2° (P=.633); a mean deviation from the desired anteversion (15°) of 5.5° and 6.6° (P=.429); a mean deviation from the desired inclination of 3° and 3.2° (P=.783); and location inside the safe zone of 90% and 80% (P=.661). The acetabular component position's tomography analyses were similar whether using the imageless navigation or performing it conventionally. Published by Elsevier Inc.

Clinical outcome of pedestal cup endoprosthetic reconstruction after resection of a peri-acetabular tumour

NARCIS (Netherlands)

Bus, M. P. A.; Boerhout, E. J.; Bramer, J. A. M.; Dijkstra, P. D. S.

2014-01-01

Peri-acetabular tumour resections and their subsequent reconstruction are among the most challenging procedures in orthopaedic oncology. Despite the fact that a number of different pelvic endoprostheses have been introduced, rates of complication remain high and long-term results are mostly lacking.

What is the role of clinical tests and ultrasound in acetabular labral tear diagnostics?

DEFF Research Database (Denmark)

Troelsen, Anders; Mechlenburg, Inger; Gelineck, John

2009-01-01

BACKGROUND AND PURPOSE: An acetabular labral tear is a diagnostic challenge. Various clinical tests have been described, but little is known about their diagnostic sensitivity and specificity. We investigated the diagnostic validity of clinical tests and ultrasound as compared with MR arthrography...... no or only slight signs of osteoarthritis (Tönnis grade 0-1). RESULTS: MR arthrography identified labral tears in 17 of the 18 hips. Ultrasound had a sensitivity of 94%, a positive predictive value of 94%, and was false negative in only 1 case compared to MR arthrography. The impingement test had the best...... diagnostic ability of the clinical tests, with a sensitivity of 59% and a specificity of 100%. The positive predictive value was 100% while the negative predictive value was 13%. INTERPRETATION: The impingement test is helpful in identifying acetabular labral tears. If this test is negative and if a labral...

Trabecular metal acetabular components in primary total hip arthroplasty

DEFF Research Database (Denmark)

Laaksonen, Inari; Lorimer, Michelle; Gromov, Kirill

2018-01-01

Background and purpose - Trabecular metal (TM) cups have demonstrated favorable results in acetabular revision and their use in primary total hip arthroplasty (THA) is increasing. Some evidence show that TM cups might decrease periprosthetic infection (PPI) incidence. We compared the survivorship...... of TM cups with that of other uncemented cups in primary THA, and evaluated whether the use of TM cups is associated with a lower risk of PPI. Patients and methods - 10,113 primary THAs with TM cup and 85,596 THAs with other uncemented cups from 2 high-quality national arthroplasty registries were...

Computer-aided designed, three dimensional-printed hemipelvic prosthesis for peri-acetabular malignant bone tumour.

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Wang, Baichuan; Hao, Yongqiang; Pu, Feifei; Jiang, Wenbo; Shao, Zengwu

2018-03-01

Prosthetic reconstruction may be a promising treatment for peri-acetabular malignant bone tumour; however, it is associated with a high complication rate. Therefore, prosthetic design and approach of prosthetic reconstruction after tumour resection warrant study. We retrospectively analyzed 11 patients with peri-acetabular malignant bone tumours treated by personalized 3D-printed hemipelvic prostheses after en bloc resection between 2015 and 2016. Pre-operative and post-operative pain at rest was assessed according to a 10-cm VAS score. The results of functional improvement were evaluated using the MSTS-93 score at the final follow-up. We also analyzed tumour recurrence, metastases, and complications associated with the reconstruction procedure. All patients were observed for six to 24 months with an average follow-up of 15.5 months. One patient had occasional pain of the involved hip at the final follow-up (VAS, pre vs. post 8 months: 3 vs. 2). The mean MSTS-93 score was 19.2 (range, 13-25). Hip dislocation was detected in two patients, while delayed wound healing occurred in one patient. One patient with mesenchymal chondrosarcoma had a left iliac bone metastasis. Local tumour recurrence was not observed. Reconstruction of bony defect after tumour resection using personalized 3D-printed hemipelvic prostheses can obtain acceptable functional results without severe complications. Based on previous reports and our results, we believe that reconstruction arthroplasty using 3D-printed hemipelvic prostheses will provide a promising alternative for those patients with peri-acetabular malignant bone tumours. Level IV, therapeutic study.

A murine model for developmental dysplasia of the hip: ablation of CX3CR1 affects acetabular morphology and gait

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George Feldman

2017-11-01

Full Text Available Abstract Background Developmental dysplasia of the hip (DDH is a debilitating condition whose distinguishing signs include incomplete formation of the acetabulum leading to dislocation of the femur, accelerated wear of the articular cartilage and joint laxity resulting in osteoarthritis. It is a complex disorder having environmental and genetic causes. Existing techniques fail to detect milder forms of DDH in newborns leading to hip osteoarthritis in young adults. A sensitive, specific and cost effective test would allow identification of newborns that could be non-invasively corrected by the use of a Pavlik harness. Previously, we identified a 2.5 MB candidate region on human chromosome 3 by using linkage analysis of a 4 generation, 72 member family. Whole exome sequencing of the DNA of 4 severely affected members revealed a single nucleotide polymorphism variant, rs3732378 co-inherited by all 11 affected family members. This variant causes a threonine to methionine amino acid change in the coding sequence of the CX3CR1 chemokine receptor and is predicted to be harmful to the function of the protein To gain further insight into the function of this mutation we examined the effect of CX3CR1 ablation on the architecture of the mouse acetabulum and on the murine gait. Methods The hips of 5 and 8 weeks old wild type and CX3CR1 KO mice were analyzed using micro-CT to measure acetabular diameter and ten additional dimensional parameters. Eight week old mice were gait tested using an inclined treadmill with and without load and then underwent micro-CT analysis. Results (1 KO mice showed larger a 5–17% larger diameter left acetabula than WT mice at both ages. (2 At 8 weeks the normalized area of space (i.e. size discrepancy between the femur head and acetabulum is significantly larger [38% (p = 0.001–21% (p = 0.037] in the KO mice. (3 At 8 weeks gait analysis of these same mice shows several metrics that are consistent with impairment in

Intra- and inter-observer agreement and reliability of bone mineral density measurements around acetabular cup

DEFF Research Database (Denmark)

Mussmann, Bo Redder; Overgaard, Soren; Torfing, Trine

2017-01-01

in measuring bone density (BMD) in complex anatomic structures which might be overcome using dual-energy computed tomography (DECT).PurposeTo test inter- and intra-observer agreement and reliability of in-house segmentation software measuring BMD adjacent to acetabular cup and to compare measurements performed...... with single-energy CT (SECT) and DECT in cemented and cementless cups.Material and Methods: Twenty-four acetabular cups inserted in porcine hip specimens were scanned with SECT and DECT. Bone density was measured in a three-dimensional volume adjacent to the cup. Double measurements were performed.......Results: BMD derived from SECT was approximately four times higher than that of DECT. In both scan modes, intraclass correlation coefficient (ICC) was >0.90 with no differences between repeated measurements, except for uncemented cups where a statistically significant difference of 11 mg/cm3 was found...

A novel technique for impaction bone grafting in acetabular reconstruction of revision total hip arthroplasty using an ex vivo compaction device

International Nuclear Information System (INIS)

Akiyama, Haruhiko; Takemoto, Mitsuru; Morishima, Takkan

2011-01-01

applications. In vitro analysis provided evidence that compaction of sequential layers of well-compacted, well-graded bone aggregates, id est (i.e.), the aggregates comprising smaller sized chips at the host bone side and larger sized chips at the component side, may have the advantages of initial stability of the acetabular component and biological response of the grafted aggregates. (author)

Migration measurement of acetabular components in cementless total hip arthroplasty; Messung der Pfannenwanderung bei zementfreien Hueftimplantaten

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Eckardt, A.; Karbowski, A.; Schwitalle, M.; Vogel, J.; Boden, F.; Seeleitner, C. [Mainz Univ. (Germany). Orthopaedische Klinik und Poliklinik; Schunk, K. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Mayrhofer, P. [Innsbruck Univ. (Austria). Inst. fuer Mathematik und Geometrie

1998-08-01

Migration measurements of acetabular components using a special computer aided method (EBRA = abbrevation for the German term ``Ein-Bild-Roentgenanalyse``) were performed to evaluate early results of the implants and predict aseptic loosening. Methods: Standard ap-radiographs of the pelvis were marked, specific points were digitised. Simulating the spatial situation the programme computes lengitudinal and vertical migration of the cup. 74 acetabular components in 71 patients could be studied by migration measurements. Results: 14 patients showed migration of more than 1 mm, which is the confidence limit of this method. Each of these patients showed diverse reasons for the migration, i.e. osteoporosis of the acetabular bone stock or problems concerning the surgical technique which means malposition of the cup or insufficient reaming of the bone. There were some patients with severe congenital dysplasia of the hip and in some cases the inclination angle of the cup was too great. Conclusion: The technique applied for measuring migration of acetabular components can be useful for evaluating early instability of the implant and can be helpful in detecting problems concerning the surgical technique. (orig.) [Deutsch] Mittels der Ein-Bild-Roentgenanalyse wurden Pfannenwanderungen nach Implantation von zementfreien, sphaerischen Hueftgelenkspfannen erfasst, um Praediktoren fuer die langfristige Prognose der Implantate zu evaluieren. Methoden: Nach Markierung von Referenzpunkten in den Beckenuebersichtsaufnahmen wurden diese digitalisiert, vom Programm verrechnet und die Wanderung des Implantats im Verlauf angegeben. Bei 71 Patienten wurden von 74 Pfannen ueber einen Mindestnachuntersuchungszeitraum von 12 Monaten Migrationsmessungen durchgefuehrt. Das Konfidenzintervall der Methode liegt bei <1 mm. Bei jedem dieser Patienten fanden sich Hinweise entweder auf ein schlechtes Knochenlager, auf operationsbedingte Probleme, wenn keine ausreichende Primaerstabilitaet der Pfanne

High-precision measurements of cementless acetabular components using model-based RSA: an experimental study

DEFF Research Database (Denmark)

Baad-Hansen, Thomas; Kold, Søren; Kaptein, Bart L

2007-01-01

BACKGROUND: In RSA, tantalum markers attached to metal-backed acetabular cups are often difficult to detect on stereo radiographs due to the high density of the metal shell. This results in occlusion of the prosthesis markers and may lead to inconclusive migration results. Within the last few years...

Surgical treatment of acetabular fractures: clinical and radiological results and its complications

International Nuclear Information System (INIS)

Martinez, C; Rey, R.

2011-01-01

The objective of this work is to analyse a serie of consecutive cases of surigically treated acetabular fractures, evaluating middle-term clinical and radiological results. A retrospective analysis of clinical histories, surgical forms and X-rays was performed for 42 patients who underwent surgery in two centers (Instituto Nacional de Ortopedia y Traumatologia [INOT] and Banco de Protesis), from July 2001 through August 2007

Is radiation superior to indomethacin to prevent heterotopic ossification in acetabular fractures?: a systematic review.

NARCIS (Netherlands)

Blokhuis, T.J.; Frolke, J.P.M.

2009-01-01

Heterotopic ossification is a well-known complication after fixation of an acetabular fracture. Indomethacin and radiation therapy are used as prophylaxis to prevent heterotopic ossification. It is unclear, however, whether either is superior, although this may relate to lack of power in individual

[Acetabular anteversion angle of the hip in the Mexican adult population measured with computed tomography].

Science.gov (United States)

Rubalcava, J; Gómez-García, F; Ríos-Reina, J L

2012-01-01

Knowledge of the radiogrametric characteristics of a specific skeletal segment in a healthy population is of the utmost clinical importance. The main justification for this study is that there is no published description of the radiogrametric parameter of acetabular anteversion in a healthy Mexican adult population. A prospective, descriptive and cross-sectional study was conducted. Individuals of both genders older than 18 years and orthopedically healthy were included. They underwent a two-dimensional axial tomographic study of both hips to measure the acetabular anteversion angles. The statistical analysis consisted of obtaining central trend and scatter measurements. A multivariate analysis of variance (ANOVA) and statistical significance were performed. 118 individuals were studied, 60 males and 58 females, with a mean age of 47.7 +/- 16.7, and a range of 18-85 years. The anteversion of the entire group was 18.6 degrees + 4.1 degrees. Anteversion in males was 17.3 degrees +/- 3.5 degrees (10 degrees - 25 degrees) and in females 19.8 degrees +/- 4.7 degrees (10 degrees - 31 degrees). There were no statistically significant differences (p right and left anteversion in the entire group. However, there were statistically significant differences (p > or = 0.005) both in the right and left sides when males and females were compared. Our study showed that there are great variations in the anteversion ranges of a healthy population. When our results are compared with those published by other authors the mean of most measurements exceeds 15 degrees. This should be useful to make therapeutic decisions that involve acetabular anteversion.

[One-stage operation for pelvis and acetabular fractures combined with Morel-Lavallée injury by internal fixation associated with vacuum sealing drainage].

Science.gov (United States)

Wei, Dan; Wang, Yue; Yuan, Jiabin; Tang, Xiaoming; Zhang, Bin; Lu, Bing; Tan, Bo

2014-01-01

To investigate the methods and effectiveness of one-stage operation for pelvis and acetabular fractures combined with Morel-Lavallée injury by internal fixation associated with vacuum sealing drainage (VSD). Between June 2008 and October 2012, 15 cases of pelvis and acetabular fractures combined with Morel-Lavallée injury were treated. There were 5 males and 10 females, aged from 18 to 67 years (mean, 36.8 years). Fractures were caused by traffic accident in 11 cases and crashing injury of heavy object in 4 cases. The time from injury to hospitalization was 3 hours to 9 days (mean, 5.4 days). Morel-Lavallée injury located in the above posterior superior iliac spine in 4 cases, greater trochanter in 7 cases, and anterior proximal thigh in 4 cases. In 10 cases complicated by pelvic fracture, there were 1 case of anteroposterior compression type, 3 cases of lateral compression type, 5 cases of vertical shear type, and 1 case of compound injury type; in 5 cases complicated by acetabular fracture, there were 1 case of transverse fracture, 1 case of posterior wall and posterior column fracture, 1 case of transverse acetabulum plus posterior wall fracture, and 2 cases of both columns fracture. Open reduction and internal fixation were used to treat pelvic and acetabular fractures, and VSD to treat Morel-Lavallée injury. When the drainage volume was less than 20 mL/d, interrupted wound suture or free skin grafting was performed. The hospitalization time was 16-31 days (mean, 20.8 days). Thirteen cases were followed up 4-16 months (mean, 7.8 months). The healing time of Morel-Lavallée injury was 16-36 days after operation (mean, 21.3 days). All the wounds had primary healing, and no infection occurred. The X-ray films showed that all fractures healed, with a mean healing time of 13.6 weeks (range, 11-18 weeks). At 6.5 months after operation, according to Majeed function scoring system in 8 cases of pelvic fracture, the results were excellent in 5 cases, good in 2 cases

Outcome of periacetabular osteotomy for the management of acetabular dysplasia: experience in an academic centre.

LENUS (Irish Health Repository)

Burke, Neil G

2011-02-01

Periacetabular osteotomy (PAO) is a very effective reconstructive procedure for treatment of acetabular dysplasia. An orthopaedic paediatric surgeon and a reconstructive hip arthroplasty surgeon performed this procedure together in the early phase of their learning curve and then performed it individually. The early clinical and radiographic results of 85 consecutive PAOs performed in this academic orthopaedic unit were reviewed. The mean Merle-d\\'Aubigné score increased from 12.4 preoperatively to 16 at follow-up. Pre-operatively 73 hips were anteverted and 12 were neutral or retroverted. The mean angle of Wiberg improved from 5 degrees to 21 degrees (p < 0.0001) in anteverted hips, and from 9 degrees to 30 degrees in neutral or retroverted hips. The mean angle of Lequesne and de Sèze improved from 6 degrees to 35 degrees (p < 0.0001) in anteverted hips, and in neutral or retroverted hips from 9 degrees to 30 degrees (p < 0.0001). The acetabular index improved from 26 degrees to 8 degrees (p < 0.0001) in anteverted hips, and from 21 degrees to 7 degrees (p < 0.0001) in neutral or retroverted hips. Over the 7 year period the blood loss and operative time improved from 2000 ml to 900 ml and 4 hours to 2 hours respectively. Four hips (four patients) required conversion to total hip replacement. The radiographic correction and improved clinical scores are similar to those in previous studies. This study shows a survival rate of 94% at 58 months following periacetabular osteotomy. The learning curve and the early results of this procedure performed in our academic unit are encouraging.

Acetabular labral tears: contrast-enhanced MR imaging under continuous leg traction

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Nishii, T. [Div. of Functional Diagnostic Imaging, Biomedical Research Center, Osaka Univ. Medical School, Suita (Japan); Nakanishi, K. [Dept. of Radiology, Osaka Univ. Medical School, Suita (Japan); Sugano, N. [Dept. of Orthopaedic Surgery, Osaka Univ. Medical School, Suita (Japan); Naito, H. [Div. of Functional Diagnostic Imaging, Biomedical Research Center, Osaka Univ. Medical School, Suita (Japan); Tamura, S. [Div. of Functional Diagnostic Imaging, Biomedical Research Center, Osaka Univ. Medical School, Suita (Japan); Ochi, T. [Dept. of Orthopaedic Surgery, Osaka Univ. Medical School, Suita (Japan)

1996-05-01

The objective of this study was to evaluate the effects of continuous leg traction on contrast-enhanced MR imaging of the hip joint and to determine whether MR imaging under these conditions is useful for demonstrating acetabular labral tears. Nineteen hips underwent MR imaging with a T1-weighted spin-echo sequence, followed by MR imaging under continuous leg traction after intravenous injection of gadolinium-DTPA. Joint fluid enhancement and labral contour detection were evaluated. Eleven hips had labral tears shown by conventional arthrography, arthroscopy and macroscopic surgical findings. Assessment of labral tears by MR imaging was correlated with the diagnosis based on these standard techniques. Joint fluid enhancement was obtained in all hips at 30 min after injection. Superior and inferior labral surfaces were completely delineated in 1 hip on the unenhanced MR images, and in 7 and 13 hips, respectively, on the enhanced images under traction. The enhanced images under traction depicted 9 of the 11 labral tears. Comparison between the unenhanced image and the enhanced image under traction avoided mistaking undercutting of the labrum for a tear in 4 hips. Contrast-enhanced MR imaging under traction was valuable for detecting labral tears non-invasively and without radiation. Follow-up examinations using this method in patients with acetabular dysplasia can help to clarify the natural course of labral disorders and enable better treatment planning. (orig./MG)

Surgical treatment of isolated aseptic acetabular loosening of the hip joint

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Zvereva К.Р.

2017-09-01

Full Text Available Aseptic acetabular loosening is one of the most common complications of primary hip arthroplasty Its treatment is possible in the volume of replacement of only the endoprosthesis cup with the preservation of a stable correctly oriented femoral component. The sequence of actions consists of provision of access to the acetabulum component and its replacement, after which the necessary offset is selected by changing the size of the head and installing a new pair of friction. Currently, the vast majority of the installed heads during the primary and revision hip replacement have a standard size forthe cone of the femoral component 12/14mm. According to the observations, in 3% of cases, there are femoral components with non-standard cone sizes 11/13 mm, usually established 7-8 years ago. The absence of heads forthe necessary cone leads to the need to replace the stable correctly oriented femoral component, which is accompanied by an increase in the time of intervention, the volume of intraoperative blood loss and the risk of intraopera-tive peri-prosthetic fracture. We represent the clinical case of a 75-year-old patient with a dislocation of the acetabular component and a stable correctly oriented femoral component, which during the audit intervention due to the lack of heads for an irregular cone size, total replacement of the components was made.

Percutaneous Fixation of Anterior Column Acetabular Fracture in a Renal Transplant Recipient

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Halil Ceylan

2013-01-01

Full Text Available Renal transplantation, performed per million population, ranges from 30 to 60 in developed countries. The transplanted kidney is generally placed in iliac fossa; therefore the treatment procedure of the pelvic trauma in these patients should be selected carefully. The gold standard technique for the treatment of displaced acetabulum fractures is open reduction and internal fixation. Our patient had received a living-related-donor renal transplant due to chronic renal failure. In the second year of transplantation, she had been injured in a motor-vehicle accident, and radiographs showed a right acetabular anterior column fracture and left pubic rami fractures. The patient was treated with percutaneous fixation techniques and at one year of postoperative period there was no evidence of degenerative signs and the clinical outcome was good. Beside having the advantage of avoiding dissection through the iliac fossa by the standard ilioinguinal approach, percutaneous techniques, with shorter surgical time, decreasing soft tissue disruption, and the potential for early discharge from hospital might be ideal for a renal transplant recipient carrying a higher risk of infection. Percutaneous fixation of selected acetabular fractures in a renal transplant recipient would presumably have the potential to decrease the morbidity associated with traditional open surgical procedures.

Acetabular reconstruction with human and bovine freeze-dried bone grafts and a reinforcement device

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Ricardo Rosito

2008-01-01

Full Text Available BACKGROUND: This is a cohort trial (1997-2005 of 49 patients submitted to an acetabular component revision of a total hip arthroplasty, using impacted human and bovine freeze-dried cancellous bone grafts (H&FDBG and a reinforcement device. OBJECTIVE: To compare clinical/radiographic graft incorporation capability between cancellous bone grafts. PATIENTS/METHODS: There were two groups: I (n=26 receiving human grafts and II (n=25 receiving bovine grafts. The average follow-up times were 55 and 49 months, respectively. Clinical analysis was based on the Merle d'Aubigné and Postel score, and the radiographic analysis involved an established score based on Conn's et al. criteria for radiographic bone incorporation. RESULTS: No clinical/radiographic differences were found between the groups and both showed an overall rate of 88.5% and 76% of graft incorporation (p=0.424. CONCLUSION: The results presented here are comparable to those in the literature with the use of deep-FG. Therefore, cancellous bone grafts can be safely and adequately used in acetabular component revision in total hip arthroplasty.

Use of a constrained tripolar acetabular liner to treat intraoperative instability and postoperative dislocation after total hip arthroplasty: a review of our experience.

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Callaghan, John J; O'Rourke, Michael R; Goetz, Devon D; Lewallen, David G; Johnston, Richard C; Capello, William N

2004-12-01

Constrained acetabular components have been used to treat certain cases of intraoperative instability and postoperative dislocation after total hip arthroplasty. We report our experience with a tripolar constrained component used in these situations since 1988. The outcomes of the cases where this component was used were analyzed for component failure, component loosening, and osteolysis. At average 10-year followup, for cases treated for intraoperative instability (2 cases) or postoperative dislocation (4 cases), the component failure rate was 6% (6 of 101 hips in 5 patients). For cases where the constrained liner was cemented into a fixed cementless acetabular shell, the failure rate was 7% (2 of 31 hips in 2 patients) at 3.9-year average followup. Use of a constrained liner was not associated with an increased osteolysis or aseptic loosening rate. This tripolar constrained acetabular liner provided total hip arthroplasty construct stability in most cases in which it was used for intraoperative instability or postoperative dislocation.

Usefulness of Arthroscopic Treatment of Painful Hip after Acetabular Fracture or Hip Dislocation.

Science.gov (United States)

Hwang, Jung-Taek; Lee, Woo-Yong; Kang, Chan; Hwang, Deuk-Soo; Kim, Dong-Yeol; Zheng, Long

2015-12-01

Painful hip following hip dislocation or acetabular fracture can be an important signal for early degeneration and progression to osteoarthritis due to intraarticular pathology. However, there is limited literature discussing the use of arthroscopy for the treatment of painful hip. The purpose of this retrospective study was to analyze the effectiveness and benefit of arthroscopic treatment for patients with a painful hip after major trauma. From July 2003 to February 2013, we reviewed 13 patients who underwent arthroscopic treatment after acetabular fracture or hip dislocation and were followed up for a minimum of 2 postoperative years. The degree of osteoarthritis based on the Tonnis classification pre- and postoperatively at final follow-up was determined. Clinical outcomes were evaluated using visual analogue scale for pain (VAS) and modified Harris hip score (MHHS), and range of motion (ROM) of the hip pre- and postoperatively at final follow-up. There were nine male and four female patients with a mean age at surgery of 28 years (range, 20 to 50 years). The mean follow-up period of the patients was 59.8 months (range, 24 to 115 months), and the mean interval between initial trauma and arthroscopic treatment was 40.8 months (range, 1 to 144 months). At the final follow-up, VAS and MHHS improved significantly from 6.3 and 53.4 to 3.0 and 88.3, respectively (p = 0.002 and p hip flexion, abduction, adduction, external rotation, and internal rotation as minor improvements from 113.1°, 38.5°, 28.5°, 36.5°, and 22.7° to 118.5°, 39.0°, 29.2°, 38.9°, and 26.5° were observed, respectively (p = 0.070, p = 0.414, p = 0.317, p = 0.084, and p = 0.136, respectively). None of the patients exhibited progression of osteoarthritis of the hip at the final follow-up. Arthroscopic treatment after acetabular fracture or hip dislocation is effective and delays the progression of traumatic osteoarthritis.

[Correlation analysis between residual displacement and hip function after reconstruction of acetabular fractures].

Science.gov (United States)

Ma, Kunlong; Fang, Yue; Luan, Fujun; Tu, Chongqi; Yang, Tianfu

2012-03-01

To investigate the relationships between residual displacement of weight-bearing and non weight-bearing zones (gap displacement and step displacement) and hip function by analyzing the CT images after reconstruction of acetabular fractures. The CT measures and clinical outcome were retrospectively analyzed from 48 patients with displaced acetabular fracture between June 2004 and June 2009. All patients were treated by open reduction and internal fixation, and were followed up 24 to 72 months (mean, 36 months); all fractures healed after operation. The residual displacement involved the weight-bearing zone in 30 cases (weight-bearing group), and involved the non weight-bearing zone in 18 cases (non weight-bearing group). The clinical outcomes were evaluated by Merle d'Aubigné-Postel criteria, and the reduction of articular surface by CT images, including the maximums of two indexes (gap displacement and step displacement). All the data were analyzed in accordance with the Spearman rank correlation coefficient analysis. There was strong negative correlation between the hip function and the residual displacement values in weight-bearing group (r(s) = -0.722, P = 0.001). But there was no correlation between the hip function and the residual displacement values in non weight-bearing group (r(s) = 0.481, P = 0.059). The results of clinical follow-up were similar to the correlation analysis results. In weight-bearing group, the hip function had strong negative correlation with step displacement (r(s) = 0.825, P = 0.002), but it had no correlation with gap displacement (r(s) = 0.577, P = 0.134). In patients with acetabular fracture, the hip function has correlation not only with the extent of the residual displacement but also with the location of the residual displacement, so the residual displacement of weight-bearing zone is a key factor to affect the hip function. In patients with residual displacement in weight-bearing zone, the bigger the step displacement is, the

Effects of Titanium Mesh Surfaces-Coated with Hydroxyapatite/β-Tricalcium Phosphate Nanotubes on Acetabular Bone Defects in Rabbits

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Thuy-Duong Thi Nguyen

2017-07-01

Full Text Available The management of severe acetabular bone defects in revision reconstructive orthopedic surgery is challenging. In this study, cyclic precalcification (CP treatment was used on both nanotube-surface Ti-mesh and a bone graft substitute for the acetabular defect model, and its effects were assessed in vitro and in vivo. Nanotube-Ti mesh coated with hydroxyapatite/β-tricalcium phosphate (HA/β-TCP was manufactured by an anodizing and a sintering method, respectively. An 8 mm diameter defect was created on each acetabulum of eight rabbits, then treated by grafting materials and covered by Ti meshes. At four and eight weeks, postoperatively, biopsies were performed for histomorphometric analyses. The newly-formed bone layers under cyclic precalcified anodized Ti (CP-AT meshes were superior with regard to the mineralized area at both four and eight weeks, as compared with that under untreated Ti meshes. Active bone regeneration at 2–4 weeks was stronger than at 6–8 weeks, particularly with treated biphasic ceramic (p < 0.05. CP improved the bioactivity of Ti meshes and biphasic grafting materials. Moreover, the precalcified nanotubular Ti meshes could enhance early contact bone formation on the mesh and, therefore, may reduce the collapse of Ti meshes into the defect, increasing the sufficiency of acetabular reconstruction. Finally, cyclic precalcification did not affect bone regeneration by biphasic grafting materials in vivo.

Profundization of acetabular cup uncemented in total substitution of hip in-patient with acetabular dysplasia - Experience university hospital - Clinica San Rafael

International Nuclear Information System (INIS)

Dimian Mayorga, Omar David; Sandoval Daza, Alejandro; Vargas Turriago, Marcela; Perez Torres, Javier

2005-01-01

14 patients with acetabular dysplasia were treated at Hospital Universitario Clinica San Rafael with total hip arthroplasty with uncemented cup internization. According to Crowe classification, one was type 1, eight were type 2 and five were type 3. The average follow up was twenty-four months. The Harris hip score was used for the clinical evaluation with a pre operative average of 35 points and 37 points post operative. The average cup internization was four millimeters, with an average cup protrutio of 47% and an average of cup coverage of 81%. The average internization of the femoral head's center was 26mm. screws for cup fixation were used in 3 patients. We did not have complications nor implant revision at the time of follow up

Porous metal revision shells for management of contained acetabular bone defects at a mean follow-up of six years: a comparison between up to 50% bleeding host bone contact and more than 50% contact.

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Sternheim, A; Backstein, D; Kuzyk, P R T; Goshua, G; Berkovich, Y; Safir, O; Gross, A E

2012-02-01

We report the use of porous metal acetabular revision shells in the treatment of contained bone loss. The outcomes of 53 patients with ≤ 50% acetabular bleeding host bone contact were compared with a control group of 49 patients with > 50% to 85% bleeding host bone contact. All patients were treated with the same type of trabecular metal acetabular revision shell. The mean age at revision was 62.4 years (42 to 80) and the mean follow-up of both groups was 72.4 months (60 to 102). Clinical, radiological and functional outcomes were assessed. There were four (7.5%) mechanical failures in the ≤ 50% host bone contact group and no failures in the > 50% host bone contact group (p = 0.068). Out of both groups combined there were four infections (3.9%) and five recurrent dislocations (4.9%) with a stable acetabular component construct that were revised to a constrained liner. Given the complexity of the reconstructive challenge, porous metal revision acetabular shells show acceptable failure rates at five to ten years' follow-up in the setting of significant contained bone defects. This favourable outcome might be due to the improved initial stability achieved by a high coefficient of friction between the acetabular implant and the host bone, and the high porosity, which affords good bone ingrowth.

Biocompatibility of Bespoke 3D-Printed Titanium Alloy Plates for Treating Acetabular Fractures

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Xuezhi Lin

2018-01-01

Full Text Available Treatment of acetabular fractures is challenging, not only because of its complicated anatomy but also because of the lack of fitting plates. Personalized titanium alloy plates can be fabricated by selective laser melting (SLM but the biocompatibility of these three-dimensional printing (3D-printed plates remains unknown. Plates were manufactured by SLM and their cytocompatibility was assessed by observing the metabolism of L929 fibroblasts incubated with culture medium extracts using a CCK-8 assay and their morphology by light microscopy. Allergenicity was tested using a guinea pig maximization test. In addition, acute systemic toxicity of the 3D-printed plates was determined by injecting extracts from the implants into the tail veins of mice. Finally, the histocompatibility of the plates was investigated by implanting them into the dorsal muscles of rabbits. The in vitro results suggested that cytocompatibility of the 3D-printed plates was similar to that of conventional plates. The in vivo data also demonstrated histocompatibility that was comparable between the two manufacturing techniques. In conclusion, both in vivo and in vitro experiments suggested favorable biocompatibility of 3D-printed titanium alloy plates, indicating that it is a promising option for treatment of acetabular fractures.

Wear analysis by applying a pin-disc configuration to phemoral head and acetabular cup Análisis del desgaste de la articulación cabeza femoral–copa acetabular mediante simulación experimental con máquina perno-disco

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Beltrán-Fernandez Juan Alfonso

2008-07-01

Full Text Available This work determines a prosthetic hip system’s life-span, focusing on a Mexican phenotype. The total sliding equivalent distance for the system was determined, as well as the loading regime under which the femoral component and the acetabular cup were subjected in normal operating conditions. An experimental tribology essay was then performed to simulate the wearing of the components in a Pin over Disc machine. This assay (for which the test specimens were manufactured in medical grade stainless steel AISI-ASTM 316L for the femoral component and high density polyethylene for the acetabular cup was aimed at simulating wear conditions involved in 10 years of continuous operation. A numerical simulation of operational conditions (using the finite element method was performedIn for establishing assay loading conditions to accurately determine where the loads should be applied. The tribology assay led to quantifying the volumetric loss of materials for the system being analysed. It can be concluded that the methodology proposed in this work for estimating the life-span of a prosthetic hip system was valid and accurate by comparing the results with those found in the literature. A statistical validation of the proposed method is plaaned for the future. Key words: Design life; femoral component; acetabular cup; Mexican phenotype; pin-disc configuration.Este trabajo presenta un estudio que permite establecer la vida útil esperada de un sistema prostético de cadera para el caso del fenotipo mexicano. En primera instancia se determinó la distancia total equivalente de deslizamiento y las condiciones de carga entre el componente femoral y la copa acetabular bajo condiciones normales de carga. Posteriormente, se desarrolló una simulación experimental para la realización de un ensayo tribológico en una máquina de desgaste del tipo Perno sobre Disco (Pin on Disk, POD. Este ensayo sometió al conjunto fabricado en acero inoxidable AISI

Peri-acetabular radiolucent lines: inter- and intra-observer agreement on post-operative radiographs

OpenAIRE

Kneif, D.; Downing, M.; Ashcroft, G. P.; Gibson, P.; Knight, D.; Ledingham, W.; Hutchison, J.

2005-01-01

Peri-acetabular radiolucent lines (RLLs) seen on “early” post-operative radiographs have been identified as a potential predictor of long-term implant performance. This study examines the inter- and intra-observer variation encountered when assessing such radiographs. Four consultant orthopaedic surgeons assessed the presence, extent and width of RLLs in 220 radiographs performed on 50 patients taken one to two weeks, six weeks, six months and one year following surgery. Inter-observer agreem...

Does using a polyethylene RM press-fit cup modify the preparation of the acetabulum and acetabular offset in primary hip arthroplasty?

Science.gov (United States)

Erivan, R; Aubret, S; Villatte, G; Mulliez, A; Descamps, S; Boisgard, S

2017-09-01

When performing total hip arthroplasty (THA), it is important to maintain the femoral and acetabular offsets to ensure good joint stability and to restore the function of the hip abductor muscles. In our practice, we mainly use a lateralized stem and hollow out the acetabulum to the quadrilateral plate to accommodate a press-fit polyethylene cup. However, the repercussions of this preparation method, which is driven by the cup's design, are not known. We carried out a retrospective study to assess: (1) the changes in the femoral and acetabular offset; (2) the height of the center of rotation; and (3) the repercussions on wear. We hypothesized there would be no significant differences between the preoperative and postoperative femoral and acetabular offsets. We reviewed 88 primary THA cases performed with the RM Pressfit™ cup that had a minimum of 5 years' follow-up. A lateralized self-locking Muller-type cemented femoral stem was used in 92.0% of cases and a standard stem in 8.0%. Measurements were done on plain radiographs with MHP™ and Mesurim Pro™ software. The average follow-up was 6.5 years (5-8). On average, the acetabular offset was reduced by 2.75mm±5.9 mm (range: -17.5 to +10.6 mm) (Pcup in subchondral bone without contacting the quadrilateral plate. This preserves bone stock, which may be useful later on if the cup is revised, particularly in younger patients. Conversely, the femoral offset did not change significantly, despite the use of lateralized stems in 92.0% of cases. We measured an annual wear rate of 0.068mm per year, which is lower than in other published studies, possibly because our patient population was older. IV, retrospective study. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Initial stability of a highly porous titanium cup in an acetabular bone defect model.

Science.gov (United States)

Yoshimoto, Kensei; Nakashima, Yasuharu; Wakiyama, Miyo; Hara, Daisuke; Nakamura, Akihiro; Iwamoto, Mikio

2018-04-12

The purpose of this study was to quantify the initial stability of a highly porous titanium cup using an acetabular bone defect model. The maximum torque of a highly porous titanium cup, with a pore size of 640 μm and porosity of 60%, was measured using rotational and lever-out torque testing and compared to that of a titanium-sprayed cup. The bone models were prepared using a polyurethane foam block and had three levels of bone coverage: 100, 70, and 50%. The highly porous titanium cup demonstrated significantly higher maximum torque than the titanium-sprayed cups in the three levels of bone defects. On rotational torque testing, it was found to be 1.5, 1.3, and 1.3 times stronger than the titanium-sprayed cups with 100, 70 and 50% bone coverage, respectively. Furthermore, it was found to be 2.2, 2.3, and 1.5 times stronger on lever-out testing than the titanium-sprayed cup. No breakage in the porous layers was noted during the testing. This study provides additional evidence of the initial stability of highly porous titanium cup, even in the presence of acetabular bone defects. Copyright © 2018. Published by Elsevier B.V.

The acetabular fossa hot spot on {sup 18}F-FDG PET/CT: epidemiology, natural history, and proposed etiology

Energy Technology Data Exchange (ETDEWEB)

Kubicki, Shelby L. [Trinity University, San Antonio, TX (United States); Richardson, Michael L. [University of Washington, Department of Radiology, Seattle, WA (United States); Martin, Thomas [X-Ray Associates of New Mexico, Department of Radiology, Albuquerque, NM (United States); Rohren, Eric [The University of Texas M.D. Anderson Cancer Center, Department of Diagnostic Radiology, Division of Nuclear Medicine, Houston, TX (United States); Wei, Wei [The University of Texas M.D. Anderson Cancer Center, Department of Biostatistics, Houston, TX (United States); Amini, Behrang [The University of Texas M.D. Anderson Cancer Center, Department of Diagnostic Radiology, Division of Musculoskeletal Radiology, Houston, TX (United States)

2015-01-15

To describe a benign focus of increased activity in the acetabular fossa (the acetabular fossa hot spot, AFHS) on {sup 18}F-FDG PET/CT that can mimic a neoplasm. {sup 18}F-FDG PET/CT images from four patient populations were examined. Group 1 (n = 13) was collected from a search of radiology reports and used to define the AFHS and for hypothesis generation. Group 2 (n = 1,150) was used for prevalence of AFHS. Group 3 (n = 1,213) had PET/CT and MRI pelvis within a week of each other and was used to correlate metabolic and anatomic findings. Group 4 (n = 100) was used to generate the control group. Data were collected on demographics, common comorbidities, underlying cancer diagnosis and status, and hip symptoms. Prevalence of AFHS was 0.36 % (95 % CI 0.10-0.91 %). None progressed to malignancy or was associated with cancer status. The majority (71 %) were on the left, and 6 % were bilateral. Mean SUV{sub max} of the AFHS was 4.8 (range, 2.7-7.8). Male patients were more likely to have the AFHS (OR = 8.69, 95 % CI 1.88-40.13). There was no difference with respect to other collected data, including hip symptoms. Average minimum duration of AFHS was 346 days (range, 50-1,010 days). Readers did not detect corresponding hip abnormalities on MRIs. AFHS is a benign finding that may be caused by subclinical ligamentum teres injury, focal synovitis, or degeneration of acetabular fossa fat. Despite uncertainty regarding its etiology, recognition of AFHS as a benign finding can prevent morbidity associated with unnecessary biopsy or initiation of therapy. (orig.)

Radiologic analysis of femoral acetabular impingement: from radiography to MRI

Energy Technology Data Exchange (ETDEWEB)

Dwek, Jerry R. [University of California at San Diego, Department of Radiology, Rady Children' s Hospital and Health Center, San Diego, CA (United States); San Diego Imaging, San Diego, CA (United States); Monazzam, Shafagh [Rady Children' s Hospital and Health Center, Department of Orthopedics, San Diego, CA (United States); Chung, Christine B. [University of California at San Diego, Department of Radiology, San Diego, CA (United States)

2013-03-15

Femoral acetabular impingement is a set of morphologic abnormalities that are considered to be a major cause of degenerative disease in the hip joint. Early changes are already present in adolescence when it is the pediatric radiologist who must assess current damage with the aim of averting progression to more severe and debilitating osteoarthritis. A multimodality approach is used for diagnosis, that includes conventional radiography and CT to assess the osseous structures. MR arthrography is the primary advanced imaging modality for assessment of morphologic changes as well as injuries of the labrum and articular cartilage. Details of radiologic imaging are offered to guide the radiologist and provide an avenue for the accurate description of the osseous and articular alterations and injury. (orig.)

Long-term results of uncemented alumina acetabular implants.

Science.gov (United States)

Boehler, M; Knahr, K; Plenk, H; Walter, A; Salzer, M; Schreiber, V

1994-01-01

We report the clinical and tribological performance of 67 ceramic acetabular prostheses implanted between 1976 and 1979 without bone cement. They articulated with ceramic femoral heads mounted on mental femoral stems. After a mean elapsed period of 144 months, 59 sockets were radiographically stable but two showed early signs and six showed late signs of loosening. Four of the loose sockets have been revised. Histological analysis of the retrieved tissue showed a fibrous membrane around all the implants, with fibrocartilage in some. There was no bone ingrowth, and the fibrous membrane was up to 6 mm thick and infiltrated with lymphocytes, plasma cells, and macrophages. Intra- and extracellular birefringent wear particles were seen. Tribological analysis showed total wear rates in two retrieved alumina-on-alumina joints of 2.6 microns per year in a stable implant and 68 microns in a loose implant. Survival analysis showed a revision rate of 12.4% at 136 months.

Delayed cementless total hip arthroplasty for neglected dislocation of hip combined with complex acetabular fracture and deficient bone stock

Directory of Open Access Journals (Sweden)

Gavaskar Ashok S

2012-12-01

Full Text Available 【Abstract】Total hip arthroplasty (THA for an un-treated acetabular fracture is technically challenging and the long-term result is not so favorable. A 45-year-old fe-male patient with untreated column and comminuted poste-rior wall fracture of the acetabulum was treated in our insti-tution by reconstruction of the posterior wall using iliac strut autograft and plate stabilization of the posterior col-umn with cancellous grafting and cementless THA in a single stage. At 3 years’ follow-up, the patient was independently mobile without limb length discrepancy. Radiological evalu-ation showed well integrated components and bone grafts. No evidence of aseptic loosening or osteolysis was found. This report aims to emphasize that bony acetabular recon-struction allows the use of primary hip components, which improves prosthesis longevity and preserves bone stock for a future revision. Key words: Acetabulum; Fractures, bone; Hip dislocation; Arthroplasty, replacement, hip

Patients with proximal junctional kyphosis requiring revision surgery have higher postoperative lumbar lordosis and larger sagittal balance corrections.

Science.gov (United States)

Kim, Han Jo; Bridwell, Keith H; Lenke, Lawrence G; Park, Moon Soo; Song, Kwang Sup; Piyaskulkaew, Chaiwat; Chuntarapas, Tapanut

2014-04-20

Case control study. To evaluate risk factors in patients in 3 groups: those without proximal junctional kyphosis (PJK) (N), with PJK but not requiring revision (P), and then those with PJK requiring revision surgery (S). It is becoming clear that some patients maintain stable PJK angles, whereas others progress and develop severe PJK necessitating revision surgery. A total of 206 patients at a single institution from 2002 to 2007 with adult scoliosis with 2-year minimum follow-up (average 3.5 yr) were analyzed. Inclusion criteria were age more than 18 years and primary fusions greater than 5 levels from any thoracic upper instrumented vertebra to any lower instrumented vertebrae. Revisions were excluded. Radiographical assessment included Cobb measurements in the coronal/sagittal plane and measurements of the PJK angle at postoperative time points: 1 to 2 months, 2 years, and final follow-up. PJK was defined as an angle greater than 10°. The prevalence of PJK was 34%. The average age in N was 49.9 vs. 51.3 years in P and 60.1 years in S. Sex, body mass index, and smoking status were not significantly different between groups. Fusions extending to the pelvis were 74%, 85%, and 91% of the cases in groups N, P, and S. Instrumentation type was significantly different between groups N and S, with a higher number of upper instrumented vertebra hooks in group N. Radiographical parameters demonstrated a higher postoperative lumbar lordosis and a larger sagittal balance change, with surgery in those with PJK requiring revision surgery. Scoliosis Research Society postoperative pain scores were inferior in group N vs. P and S, and Oswestry Disability Index scores were similar between all groups. Patients with PJK requiring revision were older, had higher postoperative lumbar lordosis, and larger sagittal balance corrections than patients without PJK. Based on these data, it seems as though older patients with large corrections in their lumbar lordosis and sagittal balance

Influence of soft tissue in the assessment of the primary fixation of acetabular cup implants using impact analyses.

Science.gov (United States)

Bosc, Romain; Tijou, Antoine; Rosi, Giuseppe; Nguyen, Vu-Hieu; Meningaud, Jean-Paul; Hernigou, Philippe; Flouzat-Lachaniette, Charles-Henri; Haiat, Guillaume

2018-06-01

The acetabular cup (AC) implant primary stability is an important determinant for the success of cementless hip surgery but it remains difficult to assess the AC implant fixation in the clinic. A method based on the analysis of the impact produced by an instrumented hammer on the ancillary has been developed by our group (Michel et al., 2016a). However, the soft tissue thickness present around the acetabulum may affect the impact response, which may hamper the robustness of the method. The aim of this study is to evaluate the influence of the soft tissue thickness (STT) on the acetabular cup implant primary fixation evaluation using impact analyses. To do so, different AC implants were inserted in five bovine bone samples. For each sample, different stability conditions were obtained by changing the cavity diameter. For each configuration, the AC implant was impacted 25 times with 10 and 30 mm of soft tissues positioned underneath the sample. The averaged indicator I m was determined based on the amplitude of the signal for each configuration and each STT and the pull-out force was measured. The results show that the resonance frequency of the system increases when the value of the soft tissue thickness decreases. Moreover, an ANOVA analysis shows that there was no significant effect of the value of soft tissue thickness on the values of the indicator I m (F = 2.33; p-value = 0.13). This study shows that soft tissue thickness does not appear to alter the prediction of the acetabular cup implant primary fixation obtained using the impact analysis approach, opening the path towards future clinical trials. Copyright © 2018 Elsevier Ltd. All rights reserved.

Press fit shape femoral heads for acetabular reconstruction - 5 to 8 years results

International Nuclear Information System (INIS)

Obenous, C.; Girtler, R.; Schwoger, W.; Winkler, H.

1999-01-01

Filling of acetabular defects with allograft bone is a favourable method in revision-THR provided that primary stability and load bearing capability can be achieved. Since 1990 we perform structural allografting in the acetabular area using a special technique. Defects are prepared with hemispherical reamers (male) in order to obtain a smooth concave surface. Deep-frozen femoral heads are then prepared using female shapers of a diameter 0-4mm larger, thus obtaining a convex surface fitting precisely into the prepared bed. In ideal cases a press-fit can be obtained granting primary stability without additional implants, otherwise we secure the grafts against rotation with one or two traction screws in loading-direction. Implantation of the cup is performed like in primary THR, care is taken to place the implant exactly at the anatomically correct position. Weight bearing is performed as soon as after primary THR; due to the technique loads are distributed evenly over the entire contact area to host bone, pressing the graft firmly into its bed. From 1990 to 1993 this method has been used in 179 cases. 104 cases could be followed between 60 and 95 months (average 71,5 months). Mean age at operation was 66,5 years (39-87 vears). Defects were classified according to Gross as cavitary in 15, minor column in 50 and major column in 39 cases. 85x the cup has been cemented, 19x cementless. One uncemented and 7 cemented cups loosened, all within the first 2 years. 6 meanwhile have been revised a second time. Those usually were cases, where the cup was placed in a non-anatomical position and / or the graft was not secured against rotatory forces. In 17 cases we observed slight condensation of the grafts with consequent migration of the implants. Migration usually did not exceed 5mm and no other signs of implant loosening have been associated. Radiographs indicated a unifon-n pattern of rapid graft-incorporation. Remodelling seemed to be completed after the second year, from

Pelvic reconstructions following peri-acetabular bone tumour resections using a cementless ice-cream cone prosthesis with dual mobility cup.

Science.gov (United States)

Issa, Samir-Pierre; Biau, David; Babinet, Antoine; Dumaine, Valérie; Le Hanneur, Malo; Anract, Philippe

2018-01-27

Despite numerous reconstructive techniques and prosthetic devices, pelvic reconstructions following peri-acetabular malignant tumours resections are highly challenging. In the present study, we describe our experience with the Integra® (Lépine, Genay, France) ice-cream cone prosthesis in such indications. The objective was to assess the mid-term outcomes of this device. Twenty-four patients' chart with peri-acetabular malignant tumours, who underwent types II or II + III peri-acetabular resections according to Enneking and Dunham with subsequent reconstruction using the Integra® prosthesis between February 2009 and February 2015, were reviewed. Seventeen cases were primary surgeries and seven cases were revisions (i.e., failures of previous reconstructions for pelvic tumours). All living patients with the prosthesis implanted were functionally assessed, using the musculoskeletal tumour society (MSTS) and Postel-Merle d'Aubigné (PMA) scores. After a mean follow-up of 49 ± 26 months (range, 8 to 94 months), 21 patients were alive (88%), including 15 patients continuously disease-free (63%). MSTS and PMA scores averaged 72 ± 13% (range, 43 to 87%) and 14.6 ± 2.6 (range, 9 to 18), respectively. Fourteen patients (58%) presented at least one complication during follow-up, including four cases of deep infection (17%), four cases of dislocation (17%), and two mechanical failures (8%). At 5 years, the implant survival rate was 75%. In comparison to previous reconstructive techniques that we used in similar indications, functional and oncologic outcomes were improved with the Integra® implant. However, as commonly observed in pelvic bone tumour surgery, complication rates remain significant. Therapeutic, Level IV-Retrospective Cases Series.

3D printing utility for surgical treatment of acetabular fractures.

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Chana Rodríguez, F; Pérez Mañanes, R; Narbona Cárceles, F J; Gil Martínez, P

2018-05-25

Preoperative 3D modelling enables more effective diagnosis and simulates the surgical procedure. We report twenty cases of acetabular fractures with preoperative planning performed by pre-contouring synthesis plates on a 3D printed mould obtained from a computarized tomography (CT) scan. The mould impression was made with the DaVinci 1.0 printer model (XYZ Printing). After obtaining the printed hemipelvis, we proceeded to select the implant size (pelvic Matta system, Stryker ® ) that matched the characteristics of the fracture and the approach to be used. Printing the moulds took a mean of 385minutes (322-539), and 238grams of plastic were used to print the model (180-410). In all cases, anatomic reduction was obtained and intra-operative changes were not required in the initial contouring of the plates. The time needed to perform the full osteosynthesis, once the fracture had been reduced was 16.9minutes (10-24). In one case fixed with two plates, a postoperative CT scan showed partial contact of the implant with the surface of the quadrilateral plate. In the remaining cases, the contact was complete. In conclusion, our results suggest that the use of preoperative planning, by printing 3D mirror imaging models of the opposite hemipelvis and pre-contouring plates over the mould, might effectively achieve a predefined surgical objective and reduce the inherent risks in these difficult procedures. Copyright © 2018. Publicado por Elsevier España, S.L.U.

Long-term retrospective study on the placement of the cementless acetabular cup and clinical outcomes in patients undergoing femoral head autografting for hip dysplasia and total hip arthroplasty.

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Ozden, Vahit Emre; Dikmen, Goksel; Beksac, Burak; Tozun, Ismail Remzi

2018-05-01

Placement of acetabular cup in the dysplastic hip is a challenging procedure. Using bulk femoral head autograft to increase the bony coverage of the cup is one of the techniques, which have been described. The impact of cup position on cup and autograft survival is a controversial issue. We aimed to determine whether the position of cementless acetabular cup used in conjunction with femoral head autograft in dysplastic hips affected the autograft-host incorporation with its final radiographic appearance and the cup survivorship into the second decade. Thirty-eight dysplastic hips with varying Crowe types in 31 patients (30 women and one man) were included. The mean age was 47 years (range, 29-64 years) and the mean follow-up was 20.3 years (range, 14.8-25.9 years). The initial postoperative and final radiographs were evaluated. The survival rate of the cups was analysed using Kaplan-Meier statistics and the log-rank test. Multivariate analysis was used to evaluate the effect of variables (Crowe type, radiographic initial host bone coverage over the cup and position of the cup) on survivorship. The acetabular cups were positioned anatomical in 27/38 hips according to Ranawat measurement technique. Trabecular bridging at graft-host interface was seen in all cases at an average 22.1 months. Neither acetabular cup position nor initial host bone coverage over acetabular cup less than 50% had any significant effect on either cup survival or final radiographic appearance of the graft. The 20-year cup survival rate without aseptic revision was 66% (95 CI, 52%-84%). No revision was performed due to graft resorption. Twenty-year survival rate of the cementless cup combination with femoral head autograft showed no significant differences whether it was placed at high or anatomic hip centre. The final radiographic appearance of the autograft was not affected from either the cup location or the initial radiographic horizontal host bone coverage. Copyright © 2018 The Japanese

Ultrasound in Total Hip Replacement: Value of Anterior Acetabular Cup Visibility and Contact With the Iliopsoas Tendon.

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Guillin, Raphaël; Bertaud, Valérie; Garetier, Marc; Fantino, Olivier; Polard, Jean-Louis; Lambotte, Jean-Christophe

2018-06-01

To assess visibility of the acetabular cup in total hip replacement and to determine the value of direct and indirect signs of iliopsoas impingement syndrome with ultrasound. Ultrasound examinations were performed by a single operator in 17 patients with iliopsoas impingement syndrome and 48 control patients. Cup visibility, contact between the cup and psoas tendon, and the presence of indirect signs of iliopsoas impingement syndrome were investigated in all patients. When the acetabular cup was visible, its size and position in relation to the psoas tendon were recorded. Anterior cup visibility (P = .03), contact with the psoas tendon (P cup shift of 3 mm or greater yielded respective sensitivities of 82% and 59% and specificities of 81% and 100%. When iliopsoas impingement syndrome is clinically suspected, the presence of iliopsoas bursitis or a posteroanterior cup shift of greater than 3 mm under the psoas tendon serve to confirm the diagnosis. In the absence of these conditions, a therapeutic test may be necessary because of the incomplete, albeit high, specificity of other signs. © 2017 by the American Institute of Ultrasound in Medicine.

Discrete element analysis is a valid method for computing joint contact stress in the hip before and after acetabular fracture.

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Townsend, Kevin C; Thomas-Aitken, Holly D; Rudert, M James; Kern, Andrew M; Willey, Michael C; Anderson, Donald D; Goetz, Jessica E

2018-01-23

Evaluation of abnormalities in joint contact stress that develop after inaccurate reduction of an acetabular fracture may provide a potential means for predicting the risk of developing post-traumatic osteoarthritis. Discrete element analysis (DEA) is a computational technique for calculating intra-articular contact stress distributions in a fraction of the time required to obtain the same information using the more commonly employed finite element analysis technique. The goal of this work was to validate the accuracy of DEA-computed contact stress against physical measurements of contact stress made in cadaveric hips using Tekscan sensors. Four static loading tests in a variety of poses from heel-strike to toe-off were performed in two different cadaveric hip specimens with the acetabulum intact and again with an intentionally malreduced posterior wall acetabular fracture. DEA-computed contact stress was compared on a point-by-point basis to stress measured from the physical experiments. There was good agreement between computed and measured contact stress over the entire contact area (correlation coefficients ranged from 0.88 to 0.99). DEA-computed peak contact stress was within an average of 0.5 MPa (range 0.2-0.8 MPa) of the Tekscan peak stress for intact hips, and within an average of 0.6 MPa (range 0-1.6 MPa) for fractured cases. DEA-computed contact areas were within an average of 33% of the Tekscan-measured areas (range: 1.4-60%). These results indicate that the DEA methodology is a valid method for accurately estimating contact stress in both intact and fractured hips. Copyright © 2017 Elsevier Ltd. All rights reserved.

Precision of radiostereometric analysis (RSA) of acetabular cup stability and polyethylene wear improved by adding tantalum beads to the liner

DEFF Research Database (Denmark)

Nebergall, Audrey K; Rader, Kevin; Palm, Henrik

2015-01-01

segment to measure wear and acetabular cup stability. The standard deviation multiplied by the critical value (from a t distribution) established the precision of each method. Results - Due to the imprecision of the automated edge detection, the shell-only method was least desirable. The shell + liner...

[Total hip arthroplasty in post-dysplastic hip arthritis. Can type and position of the acetabular component influence longevity of the prosthesis?].

Science.gov (United States)

Fousek, J; Indráková, P

2007-02-01

The aim of the study was a retrospective evaluation of our patients with post-dysplastic hips treated by cemented or non-cemented total hip arthroplasty (THA) in order to ascertain which type and position of the acetabular component was most effective. In the years 1999-2002, 111 THA procedures were performed in 93 patients, 76 women and 17 men, with post-dysplastic hip arthritis. The average age of the patients at the time of implantation was 52.6 years. On the basis of pre-operative radiographic findings, the patients' conditions were evaluated using the Hartofilakidis classification into three disease categories: dysplasia, low dislocation and high dislocation, and the patients were placed in two groups. Group 1 included 78 patients, and group 2 comprised 26 patients. None of our patients was classified as having high dislocation. Thirty-nine of these patients had previously undergone surgery for dysplastic hips. A total of 104 THAs were evaluated, because radiographic data was incomplete in seven cases. In addition to X-ray findings, the prosthesis type (cemented, hybrid, non-cemented), post-operative complications and signs of loosening were included in the evaluation. Clinical outcomes were assessed by the Harris score. The follow-up terminating on 31st December 2005 was 67 months on the average. In group 1 patients, the average Harris score increased from 38.6 to 80.3 points and in group 2 patients from 35.5 to 84.9 points, mostly with excellent and good results. In 72.1 % of the hips, a press-fit acetabular component was implanted. In 55.8 % of the cases, the acetabular component was implanted off the anatomical center of rotation, into the high hip center, with the range from 9 to 20 mm and an average of 15 mm. The average limb lengthening was 2.5 cm, ranging from 1.0 to 3.5 cm. Our results show that it is more effective to use non-cemented THA for post-dysplastic hips. The implantation of a noncemented acetabular component into the high center provides

Failure mechanisms and closed reduction of a constrained tripolar acetabular liner.

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Robertson, William J; Mattern, Christopher J; Hur, John; Su, Edwin P; Pellicci, Paul M

2009-02-01

Unlike traditional bipolar constrained liners, the Osteonics Omnifit constrained acetabular insert is a tripolar device, consisting of an inner bipolar bearing articulating within an outer, true liner. Every reported failure of the Omnifit tripolar implant has been by failure at the shell-bone interface (Type I failure), failure at the shell-liner interface (Type II failure), or failure of the locking mechanism resulting in dislocation of the bipolar-liner interface (Type III failure). In this report we present two cases of failure of the Omnifit tripolar at the bipolar-femoral head interface. To our knowledge, these are the first reported cases of failure at the bipolar-femoral head interface (Type IV failure). In addition, we described the first successful closed reduction of a Type IV failure.

High proximal migration in cemented acetabular revisions operated with bone impaction grafting; 47 revision cups followed with RSA for 17 years.

Science.gov (United States)

Mohaddes, Maziar; Herberts, Peter; Malchau, Henrik; Johanson, Per-Erik; Kärrholm, Johan

2017-05-12

Bone impaction grafting is a biologically and mechanically appealing option in acetabular revision surgery, allowing restitution of the bone stock and restoration of the biomechanics. We analysed differences in proximal migration of the revision acetabular components when bone impaction grafting is used together with a cemented or an uncemented cup. 43 patients (47 hips), revised due to acetabular loosening and judged to have less than 50% host bone-implant contact were included. The hips were randomised to either an uncemented (n = 20) or a cemented (n = 27) revision cup. Radiostereometry and radiography was performed postoperatively, at 3 and 6 months, 1, 2, 3, 5, 7, 10 and 13 and 17 years postoperatively. Clinical follow-up was performed at 1, 2 and 5 years postoperatively and thereafter at the same interval as in the radiographic follow-up. There were no differences in the base line demographic data between the 2 groups. At the last follow-up (17 years) 14 hips (10 cemented, 4 uncemented) had been re-revised due to loosening. 3 additional cups (1 uncemented and 2 cemented) were radiographically loose. There was a higher early proximal migration in the cemented cups. Cups operated on with cement showed a higher early migration measured with RSA and also a higher number of late revisions. The reason for this is not known, but factors such as inclusion of cases with severe bone defects, use of smaller bone chips and issues related to the impaction technique might have had various degrees of influence.

Clinical applications for multiplanar- and three-dimensional-reconstructions by helical-CT for the diagnosis of acetabular fractures

International Nuclear Information System (INIS)

Stroszczynski, C.; Schedel, H.; Stoeckle, U.; Wellmann, A.; Beier, J.; Wicht, L.; Hoffmann, R.; Felix, R.

1996-01-01

This review describes recent visualizations of computed tomography for the diagnosis of acetabular fractures. The techniques of conventional and helical-CT for the imaging of the acetabulum are compared. Furthermore, the different methods of multiplaner and three-dimensional reconstructions e.g. shaded surface display, maximum intensity projection, and volume rendering are presented. Figures of multiplanar and three-dimensional imaging for fractures of the pelvis is discussed. (orig.) [de

Overdiagnosing of femoroacetabular impingement: correlation between clinical presentation and computed tomography in symptomatic patients☆

Science.gov (United States)

Canella, Richard Prazeres; Adam, Guilherme Pradi; de Castillo, Roberto André Ulhôa; Codonho, Daniel; Ganev, Gerson Gandhi; de Vicenzi, Luiz Fernando

2016-01-01

Objective To correlate the angles between the acetabulum and the proximal femur in symptomatic patients with femoroacetabular impingement (FAI), using computed tomography (CT). Methods We retrospectively evaluated 103 hips from 103 patients, using multislice CT to measure the acetabular age, acetabular version (in its supraequatorial portion and in its middle third), femoral neck version, cervical-diaphyseal and alpha angles and the acetabular depth. For the statistical analysis, we used the Pearson correlation coefficient. Results There were inverse correlations between the following angles: (1) acetabular coverage versus alpha angle (p = 0.019); (2) acetabular version (supraequatorial) versus alpha angle (p = 0.049). For patients with femoral anteversion lower than 15 degrees: (1) acetabular version (supraequatorial) versus alpha angle (p = 0.026); (2) acetabular version (middle third) versus alpha angle (p = 0.02). For patients with acetabular version (supraequatorial) lower than 10 degrees: (1) acetabular version (supraequatorial) versus alpha angle (p = 0.004); (2) acetabular version (middle third) versus alpha angle (p = 0.009). Conclusion There was a statistically significant inverse correlation between the acetabular version and alpha angles (the smaller the acetabular anteversion angle was, the larger the alpha angle was) in symptomatic patients, thus supporting the hypothesis that FAI occurs when cam and pincer findings due to acetabular retroversion are seen simultaneously, and that the latter alone does not cause FAI, which leads to overdiagnosis in these cases. PMID:27069890

Preliminary application of computer-assisted patient-specific acetabular navigational template for total hip arthroplasty in adult single development dysplasia of the hip.

Science.gov (United States)

Zhang, Yuan Z; Chen, Bin; Lu, Sheng; Yang, Yong; Zhao, Jian M; Liu, Rui; Li, Yan B; Pei, Guo X

2011-12-01

The considerable variation in anatomical abnormalities of hip joints associated with different types of developmental dysplasia of hip (DDH) makes reconstruction in total hip arthroplasty (THA) difficult. It is desirable to create patient-specific designs for THA procedures. In the cases of adult single DDH, an accuracy-improved method has been developed for acetabular cup prosthesis implantation of hip arthroplasty. From October 2007 to November 2008, 22 patients with single DDH (according to the Crowe standard, all dysplasia hips were classified as type I) were scanned with spiral CT pre-operatively. These patients scheduled for THA were randomly assigned to undergo either conventional THA (control group, n = 11) or navigation template implantation (NT group, n = 11). In the NT group, three-dimensional (3D) CT pelvis image data were transferred to a computer workstation and 3D models of the hip were reconstructed using the Mimics software. The 3D models were then processed by the Imageware software. In brief, a template that best fitted the location and shape of the acetabular cup was 'reversely' built from the 3D model, the rotation centre of the pathological hip determined by mirroring that of the healthy site, and a guiding hole in the template was then designed. The navigational templates were manufactured using a rapid prototyping machine. These navigation templates guide acetabular component placement. Based on the predetermined abduction angle 45° and anteversion angle 18°, after 1 year follow-up, the NT group showed significantly smaller differences (1.6° ± 0.4°, 1.9° ± 1.1°) from the predetermined angles than those in the control group (5.8° ± 2.9°, 3.9° ± 2.5°) (P < 0.05). The template designs facilitated accurate placement of acetabular components in dysplasia of acetabulum. The hip's center of rotation in DDH could be established using computer-aided design, which provides a useful method for the accurate

Supra-Acetabular Brown Tumor due to Primary Hyperparathyroidism Associated with Chronic Renal Failure

Directory of Open Access Journals (Sweden)

Rosaria M. Ruggeri

2010-01-01

Full Text Available A 63-year-old woman presented to the Orthopedic Unit of our hospital complaining of right hip pain of 6 months'duration associated with a worsening limp. Her past medical history included chronic renal insufficiency. Physical examination revealed deep pain in the iliac region and severe restriction of the right hip's articular function in the maximum degrees of range of motion. X-rays and CT scan detected an osteolytic and expansive lesion of the right supra-acetabular region with structural reabsorption of the right iliac wing. 99mTc-MDP whole-body bone scan showed an abnormal uptake in the right iliac region. Bone biopsy revealed an osteolytic lesion with multinucleated giant cells, indicating a brown tumor. Serum intact PTH was elevated (1020 pg/ml; normal values, 12 62 pg/ml, but her serum calcium was normal (total = 9.4 mg/dl, nv 8.5–10.5; ionized = 5.0 mg/dl, nv 4.2–5.4 due to the coexistence of chronic renal failure. 99mTc-MIBI scintigraphy revealed a single focus of sestamibi accumulation in the left retrosternal location, which turned out to be an intrathoracic parathyroid adenoma at surgical exploration. After surgical removal of the parathyroid adenoma, PTH levels decreased to 212 pg/ml. Three months after parathyroidectomy, the imaging studies showed complete recovery of the osteolytic lesion, thus avoiding any orthopedic surgery. This case is noteworthy because (1 primary hyperparathyroidism was not suspected due to the normocalcemia, likely attributable to the coexistence of chronic renal failure; and (2 it was associated with a brown tumor of unusual location (right supra-acetabular region.

Posterosuperior Placement of a Standard-Sized Cup at the True Acetabulum in Acetabular Reconstruction of Developmental Dysplasia of the Hip With High Dislocation.

Science.gov (United States)

Xu, Jiawei; Xu, Chen; Mao, Yuanqing; Zhang, Jincheng; Li, Huiwu; Zhu, Zhenan

2016-06-01

We sought to evaluate posterosuperior placement of the acetabular component at the true acetabulum during acetabular reconstruction in patients with Crowe type-IV developmental dysplasia of the hip. Using pelvic computed tomography and image processing, we developed a two-dimensional mapping technique to demonstrate the distribution of preoperative three-dimensional cup coverage at the true acetabulum, determined the postoperative location of the acetabular cup, and calculated postoperative three-dimensional coverage for 16 Crowe type-IV dysplastic hips in 14 patients with a mean age of 52 years (33-78 years) who underwent total hip arthroplasty. Mean follow-up was 6.3 years (5.5-7.3 years). On preoperative mapping, the maximum three-dimensional coverage using a 44-mm cup was 87.31% (77.36%-98.14%). Mapping enabled the successful replacement of 16 hips using a mean cup size of 44.13 mm (42-46 mm) with posterosuperior placement of the cup. Early weight-bearing and no prosthesis revision or loosening during follow-up were achieved in all patients. The postoperative two-dimensional coverage on anteroposterior radiographs and three-dimensional coverage were 96.15% (89.49%-100%) and 83.42% (71.81%-98.50%), respectively. This technique may improve long-term implant survival in patients with Crowe-IV developmental dysplasia of the hip undergoing total hip arthroplasty by allowing the use of durable bearings, increasing host bone coverage, ensuring initial stability, and restoring the normal hip center. Copyright © 2015 Elsevier Inc. All rights reserved.

Accessing 3D Location of Standing Pelvis: Relative Position of Sacral Plateau and Acetabular Cavities versus Pelvis

International Nuclear Information System (INIS)

Berthonnaud, E.; Hilmi, R.; Berthonnaud, E.; Berthonnaud, E.; Dimnet, J.

2012-01-01

The goal of this paper is to access to pelvis position and morphology in standing posture and to determine the relative locations of their articular surfaces. This is obtained from coupling bi planar radiography and bone modeling. The technique involves different successive steps. Punctual landmarks are first reconstructed, in space, from their projected images, identified on two orthogonal standing X-rays. Geometric models, of global pelvis and articular surfaces, are determined from punctual landmarks. The global pelvis is represented as a triangle of summits: the two femoral head centers and the sacral plateau center. The two acetabular cavities are modeled as hemispheres. The anterior sacral plateau edge is represented by an hemi-ellipsis. The modeled articular surfaces are projected on each X-ray. Their optimal location is obtained when the projected contours of their models best fit real outlines identified from landmark images. Linear and angular parameters characterizing the position of global pelvis and articular surfaces are calculated from the corresponding sets of axis. Relative positions of sacral plateau, and acetabular cavities, are then calculated. Two hundred standing pelvis, of subjects and scoliotic patients, have been studied. Examples are presented. They focus upon pelvis orientations, relative positions of articular surfaces, and pelvis asymmetries.

Editorial Commentary: The Larger Holes or Larger Number of Holes We Drill in the Coracoid, the Weaker the Coracoid Becomes.

Science.gov (United States)

Brady, Paul

2016-06-01

The larger holes or larger number of holes we drill in the coracoid, the weaker the coracoid becomes. Thus, minimizing bone holes (both size and number) is required to lower risk of coracoid process fracture, in patients in whom transosseous shoulder acromioclavicular joint reconstruction is indicated. A single 2.4-mm-diameter tunnel drilled through both the clavicle and the coracoid lowers the risk of fracture, but the risk cannot be entirely eliminated. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Three-dimensional magnetic resonance imaging analysis of hip morphology in the assessment of femoral acetabular impingement

International Nuclear Information System (INIS)

Kavanagh, E.C.; Read, P.; Carty, F.; Zoga, A.C.; Parvizi, J.; Morrison, W.B.

2011-01-01

Aim: To determine a possible association between femoral-acetabular impingement (FAI) volume and the development of labral tear using a three-dimensional (3D) model reconstruction of the acetabulum and the femoral head. Materials and methods: Magnetic resonance arthrography images of the hip in 42 patients with pain and suspected labral tear were acquired using a 1.5 T MRI machine. Using 3D analysis software, outlines of the acetabular cup and femoral head were drawn and 3D reconstruction obtained. To control for differences in patient size, ratios of acetabulum : femoral head volume (AFV) and acetabulum : femoral head surface area (AFA) were used for analysis. The association between volume of acetabulum : femoral head and FAI was investigated using ANOVA analysis. Results: There were 19 men and 23 women with a mean age of 39 years (range 18-78 years). The average AFV was 0.64 (range 0.37-1.05, SD 0.16) and AFA was 0.73 (range 0.36-1.26, SD 0.23). Herniation pit was significantly associated with a small AFV. Conclusion: Femoral neck herniation pits are associated with a low AFV. Gross volume and surface area ratios do not appear to correlate with labral tears or cartilage loss. This technique will enable more advanced analysis of morphological variations associated with FAI.

Accelerated aging, natural aging, and small punch testing of gamma-air sterilized polycarbonate urethane acetabular components.

Science.gov (United States)

Kurtz, S M; Siskey, R; Reitman, M

2010-05-01

The objectives of this study were three-fold: (1) to determine the applicability of the small punch test to characterize Bionate 80A polycarbonate urethane (PCU) acetabular implants; (2) to evaluate the susceptibility of PCU acetabular implants to exhibit degradation of mechanical behavior following gamma irradiation in air and accelerated aging; and (3) to compare the oxidation of gamma-air sterilized PCU following accelerated aging and 5 years of natural shelf aging. In addition to attenuated total reflectance-Fourier transform infrared spectroscopy, we also adapted a miniature specimen mechanical test, the small punch test, for the deformable PCU cups. Accelerated aging was performed using ASTM F2003, a standard test that represents a severe oxidative challenge. The results of this study suggest that the small punch test is sufficiently sensitive and reproducible to discriminate slight differences in the large-deformation mechanical behavior of Bionate 80A following accelerated aging. The gamma-air sterilized PCU had a reduction of 9% in ultimate load after aging. Five years of shelf aging had little effect on the mechanical properties of the PCU. Overall, our findings suggest that the Bionate 80A material has greater oxidative stability than ultra-high molecular weight polyethylene following gamma irradiation in air and exposure to a severe oxidative challenge. (c) 2010 Wiley Periodicals, Inc.

Utility of radiation in the prevention of heterotopic ossification following repair of traumatic acetabular fracture

International Nuclear Information System (INIS)

Haas, Michael L.; Kennedy, Andrew S.; Copeland, Carol C.; Ames, John W.; Scarboro, Mark; Slawson, Robert G.

1999-01-01

Purpose: Heterotopic ossification (HO) is a common problem following surgical repair of traumatic acetabular fracture (TAF), potentially causing severe pain and decreased range of motion. This report analyzes the role of radiation therapy for prevention of HO in TAF. Methods and Materials: The charts of all patients who received RT to the hip following TAF repair between July 1988 and January 1998 were reviewed. Sixty-six patients were identified. RT was given in 5 fractions of 2 Gy in 45 patients, 1 fraction of 8 Gy in 17 patients, and other doses in 4 patients. Treatment fields encompassed peri acetabular tissues at highest risk for HO. Time to RT was ≤ 24 hours for 46 patients. Results: Radiographic follow-up at least 6 months following RT was available in 47/66 (71%) patients to permit Brooker classification, revealing 6 cases (13%) of Grade III HO, compared to historical incidence in this population of 50%. No Grade IV HO was found. Mean follow-up was 18 months. Four of the Grade III patients had received 10 Gy/5 fractions, and 2 received 8 Gy/1 fraction. Postoperative wound infection occurred in 6 patients, and osteonecrosis of the femoral head was found in 13. Conclusions: RT following surgical repair of TAF provides effective prophylaxis against formation of clinically significant HO. We recommend a single fraction of 7-8 Gy within 24 hours of surgery to prevent HO formation and minimize patient discomfort

Quantification of Wear and Deformation in Different Configurations of Polyethylene Acetabular Cups Using Micro X-ray Computed Tomography

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Saverio Affatato

2017-03-01

Full Text Available Wear is currently quantified as mass loss of the bearing materials measured using gravimetric methods. However, this method does not provide other information, such as volumetric loss or surface deviation. In this work, we validated a technique to quantify polyethylene wear in three different batches of ultrahigh-molecular-polyethylene acetabular cups used for hip implants using nondestructive microcomputed tomography. Three different configurations of polyethylene acetabular cups, previously tested under the ISO 14242 parameters, were tested on a hip simulator for an additional 2 million cycles using a modified ISO 14242 load waveform. In this context, a new approach was proposed in order to simulate, on a hip joint simulator, high-demand activities. In addition, the effects of these activities were analyzed in terms of wear and deformations of those polyethylenes by means of gravimetric method and micro X-ray computed tomography. In particular, while the gravimetric method was used for weight loss assessment, microcomputed tomography allowed for acquisition of additional quantitative information about the evolution of local wear and deformation through three-dimensional surface deviation maps for the entire cups’ surface. Experimental results showed that the wear and deformation behavior of these materials change according to different mechanical simulations.

Computerized tomography in evaluation of decreased acetabular and femoral anteversion

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Toennis, D.; Skamel, H.J.

2003-01-01

Computerized tomography has received a new importance. It has been shown that decreased anteversion of femur and acetabulum, when both have decreased angles, are causing pain and osteoarthritis of the hip joint. Operative treatment should be performed before osteoarthritis develops. Exact measurements therefore are necessary. The investigation should be performed in prone position to have the pelvis lying in a defined and normal position. Femoral torsion is measured between the transverse axis of the knee and the femoral neck. The transverse axis for measurement of the femoral anteversion is defined by a rectangular line to the sagittal plane. For evaluation of the femoral anteversion in total the angle of the condyles has to be added to the femoral neck angle when the knee is found in internal rotation. Acetabular anteversion should be measured at the level where the femoral head is still in full contact and congruence with the anterior margin of the acetabulum. (orig.) [de

Common site of subchondral insufficiency fractures of the femoral head based on three-dimensional magnetic resonance imaging

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Iwasaki, Kenyu; Yamamoto, Takuaki; Motomura, Goro; Karasuyama, Kazuyuki; Sonoda, Kazuhiko; Kubo, Yusuke; Iwamoto, Yukihide [Kyushu University, Department of Orthopaedic Surgery Graduate School of Medical Sciences, Higashi-ku, Fukuoka (Japan)

2016-01-15

The objective of this study was to investigate the common sites of subchondral insufficiency fractures of the femoral head (SIF) based on three-dimensional (3-D) reconstruction of MR images. In 33 hips of 31 consecutive patients diagnosed with SIF, 3-D reconstruction of the bone, fracture, and acetabular edge was performed using MR images. These 3-D images were used to measure the fractured areas and clarify the positional relationship between the fracture and degree of acetabular coverage. The fractured area in the anterior portion was significantly larger than in the posterior area. In 11 cases, the fractures contacted the acetabular edge and were distributed on the lateral portion. The indices of acetabular coverage (center-edge angle and acetabular head index) in these cases were less than the normal range. In the remaining 22 cases, the fractures were apart from the acetabular edge and distributed on the mediolateral centerline of the femoral head. The majority of these cases had normal acetabular coverage. The common site of SIF is the anterior portion. In addition, two types of SIF are proposed: (1) Lateral type: the contact stress between the acetabular edge and lateral portion of the femoral head causes SIF based on the insufficient acetabular coverage, and (2) Central type: the contact stress between the acetabular surface and the mediolateral center of the femoral head causes SIF independent from the insufficiency of acetabular coverage. These findings may be useful for considering the treatment and prevention of SIF. (orig.)

Early experience with dual mobility acetabular systems featuring highly cross-linked polyethylene liners for primary hip arthroplasty in patients under fifty five years of age: an international multi-centre preliminary study.

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Epinette, Jean-Alain; Harwin, Steven F; Rowan, Fiachra E; Tracol, Philippe; Mont, Michael A; Chughtai, Morad; Westrich, Geoffrey H

2017-03-01

To evaluate early performance of contemporary dual mobility acetabular systems with second generation annealed highly cross-linked polyethylene for primary hip arthroplasty of patients under 55 years of age. A prospective observational five years study across five centers in Europe and the USA of 321 patients with a mean age of 48.1 years was performed. Patients were assessed for causes of revision, hip instability, intra-prosthetic dissociation, Harris hip score and radiological signs of osteolysis. There were no dislocations and no intra-prosthetic dissociations. Kaplan Meier analysis demonstrated 97.51% survivorship for all cause revision and 99.68% survivorship for acetabular component revision at five years. Mean Harris hip score was 93.6. Two acetabular shells were revised for neck-rim implant impingement without dislocation and ten femoral stems were revised for causes unrelated to dual mobility implants. Contemporary highly cross-linked polyethylene dual mobility systems demonstrate excellent early clinical, radiological, and survivorship results in a cohort of patients that demand high performance from their implants. It is envisaged that DM and second generation annealed HXLPE may reduce THA instability and wear, the two most common causes of THA revision in hip arthroplasty.

Internal Fixation of Complicated Acetabular Fractures Directed by Preoperative Surgery with 3D Printing Models.

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Liu, Zhao-Jie; Jia, Jian; Zhang, Yin-Guang; Tian, Wei; Jin, Xin; Hu, Yong-Cheng

2017-05-01

The purpose of this article is to evaluate the efficacy and feasibility of preoperative surgery with 3D printing-assisted internal fixation of complicated acetabular fractures. A retrospective case review was performed for the above surgical procedure. A 23-year-old man was confirmed by radiological examination to have fractures of multiple ribs, with hemopneumothorax and communicated fractures of the left acetabulum. According to the Letounel and Judet classification, T-shaped fracture involving posterior wall was diagnosed. A 3D printing pelvic model was established using CT digital imaging and communications in medicine (DICOM) data preoperatively, with which surgical procedures were simulated in preoperative surgery to confirm the sequence of the reduction and fixation as well as the position and length of the implants. Open reduction with internal fixation (ORIF) of the acetabular fracture using modified ilioinguinal and Kocher-Langenbeck approaches was performed 25 days after injury. Plates that had been pre-bent in the preoperative surgery were positioned and screws were tightened in the directions determined in the preoperative planning following satisfactory reduction. The duration of the operation was 170 min and blood loss was 900 mL. Postoperative X-rays showed that anatomical reduction of the acetabulum was achieved and the hip joint was congruous. The position and length of the implants were not different when compared with those in preoperative surgery on 3D printing models. We believe that preoperative surgery using 3D printing models is beneficial for confirming the reduction and fixation sequence, determining the reduction quality, shortening the operative time, minimizing preoperative difficulties, and predicting the prognosis for complicated fractures of acetabulam. © 2017 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

Measuring Acetabular Cup Orientation on Antero-Posterior Radiographs of the Hip after Total Hip Arthroplasty with a Vector Arithmetic Radiological Method. Is It Valid and Verified for Daily Clinical Practice?

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Craiovan, B; Weber, M; Worlicek, M; Schneider, M; Springorum, H R; Zeman, F; Grifka, J; Renkawitz, T

2016-06-01

The aim of this prospective study is to validate a vector arithmetic method for measuring acetabular cup orientation after total hip arthroplasty (THA) and to verify the clinical practice. We measured cup anteversion and inclination of 123 patients after cementless primary THA twice by two examiners on AP pelvic radiographs with a vector arithmetic method and compared with a 3D-CT based reconstruction model within the same radiographic coronal plane. The mean difference between the radiographic and the 3D-CT measurements was - 1.4° ± 3.9° for inclination and 0.8°± 7.9° for anteversion with excellent correlation for inclination (r = 0.81, p cup position after THA on pelvic radiographs by this vector arithmetic method, there is a need for a correct postoperative ap view, with special regards to the pelvic tilt for the future. • Measuring acetabular cup orientation on anteroposterior radiographs of the hip after THA is a helpful procedure in everyday clinical practice as a first-line imaging modality• CT remains the golden standard to accurately determine acetabular cup position.• Future measuring on radiographs for cup orientation after THA should account for integration of the pelvic tilt in order to maximize the measurement accuracy. Citation Format: • Craiovan B, Weber M, Worlicek M et al. Measuring Acetabular Cup Orientation on Antero-Posterior Radiographs of the Hip after Total Hip Arthroplasty with a Vector Arithmetic Radiological Method. Is It Valid and Verified for Daily Clinical Practice?. Fortschr Röntgenstr 2016; 188: 574 - 581. © Georg Thieme Verlag KG Stuttgart · New York.

Influence of pelvic position on radiographic measurements of the prosthetic acetabular component

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Thoren, B.; Sahlstedt, B.; Uppsala Univ.

1990-01-01

A change in the position of a prosthetic acetabular component between two different radiographic examinations indicates loosening, and may be observed as tilting or migration of the socket. To determine the apparent changes in socket position caused by improper positioning of the pelvis, a full-scale model of a pelvis with attached prosthetic sockets was examined radiographically in different positions. The projected alignment of the Charnley socket indicator wire against the inter-tuberosity line was markedly influenced by the positioning of the pelvis. An alternative way of measuring the alignment is to use the long axis of the projected ellipse of the outer circumferential groove in the socket polyethylene. The thus defined socket alignment was not influenced by the positioning of the pelvis within the investigated range. No apparent socket migration was recorded within the range of pelvic rotation and inclination studied. (orig.)

Effect of centre-edge angle on clinical and quality of life outcomes after arthroscopic acetabular labral debridement.

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Wu, Ziying; Chen, Shiyi; Li, Yunxia; Li, Hong; Chen, Jiwu

2016-07-01

The aim of this study was to compare clinical and quality of life outcomes following arthroscopic acetabular labral debridement between patients with different centre-edge (CE) angle. A total of 79 patients who underwent hip labral debridement were enrolled in this study. Radiographic measurements of CE angle were collected, and patients were assigned into a normal group (25°  0.05). Additionally, there was a greater improvement in clinical scores post-operatively in the normal group compared with the dysplasia group (P 25° compared with patients with CE angle < 20°.

Hip flexor muscle size, strength and recruitment pattern in patients with acetabular labral tears compared to healthy controls.

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Mendis, M Dilani; Wilson, Stephen J; Hayes, David A; Watts, Mark C; Hides, Julie A

2014-10-01

Acetabular labral tears are a source of hip pain and are considered to be a precursor to hip osteoarthritis. Hip flexor muscles contribute to hip joint stability and function but it is unknown if their size and function is altered in the presence of labral pathology. This study aimed to investigate hip flexor muscle size, strength and recruitment pattern in patients with hip labral pathology compared to control subjects. 12 subjects diagnosed with an unilateral acetabular labral tear were compared to 12 control subjects matched for age and gender. All subjects underwent magnetic resonance imaging (MRI) of their lumbo-pelvic region. Average muscle cross-sectional area (CSA) of the iliacus, psoas, iliopsoas, sartorius, tensor fascia latae and rectus femoris muscles were measured. Hip flexion strength was measured by an externally fixed dynamometer. Individual muscle recruitment pattern during a resisted hip flexion exercise task was measured by muscle functional MRI. Hip flexor muscle strength was found to be decreased in patients with labral pathology compared to control subjects (p muscle size (all p > 0.17) and recruitment pattern (all p > 0.53). Decreased hip flexor muscle strength may affect physical function in patients with hip labral pathology by contributing to altered gait patterns and functional tasks. Clinical rehabilitation of these patients may need to include strengthening exercises for the hip flexor muscles. Copyright © 2014 Elsevier Ltd. All rights reserved.

Magnetic resonance arthrography and the prevalence of acetabular labral tears in patients 50 years of age and older

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Jayakar, Rohit; Merz, Alexa; Wang, Dean; Hame, Sharon L.; Plotkin, Benjamin; Seeger, Leanne

2016-01-01

Arthroscopy for acetabular labral tears has minimal impact on pain and function in older patients, especially in the setting of concomitant osteoarthritis. Still, many physicians seek this diagnosis with MR arthrography. Our purpose is to assess the frequency of acetabular labral tears in older patients with hip pain and correlate likelihood of labral pathology with severity of osteoarthritis as visualized on conventional radiograph. From 2004 to 2013, 208 hip MRI arthrograms and corresponding radiographs on patients aged 50 years and older were identified. Age, gender, grade and location of labral tear, alpha angle, Toennis grade, and joint space width were documented. Labral tears and alpha angle were identified and measured on MR arthrogram. Toennis grade and joint space width were measured on radiographs. On MR arthrography, true labral tearing was identified in 73 % of patients. There was some degree of labral pathology in 93.3 % of patients, and this increased to 100 % in patients with moderate to severe osteoarthritis, as defined by Toennis grade 2-3 or joint space width ≤ 2 mm. There were no statistically significant correlations between labral tear grade and Toennis grade or joint space width. Given the high frequency of labral pathology and the questionable efficacy of arthroscopic surgical intervention in older patients, MR arthrography should be primarily for those with minimal arthritis on radiograph and potential to benefit from surgery. If further imaging beyond radiographs is necessary in these patients, standard MRI may be a more appropriate imaging tool. (orig.)

Percutaneous acetabuloplasty for metastatic acetabular lesions

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Logroscino Giandomenico

2008-05-01

Full Text Available Abstract Background Osteolytic metastases around the acetabulum are frequent in tumour patients, and may cause intense and drug-resistant pain of the hip. These lesions also cause structural weakening of the pelvis, limping, and poor quality of life. Percutaneous acetabuloplasty is a mini-invasive procedure for the management of metastatic lesions due to carcinoma of the acetabulum performed in patients who cannot tolerate major surgery, or in patients towards whom radiotherapy had already proved ineffective. Methods We report a retrospective study in 25 such patients (30 acetabuli who were evaluated before and after percutaneous acetabuloplasty, with regard to pain, mobility of the hip joint, use of analgesics, by means of evaluation forms: Visual Analog Scale, Harris Hip Score, Western Ontario and McMaster Universities Index of Osteoarthritis (WOMAC, Eastern Cooperative Oncology Group (ECOG. The results obtained were analysed using the χ2 Test and Fisher's exact test. Significance was sent at P Results Marked clinical improvement was observed in all patients during the first six post-operative months, with gradual a worsening thereafter from deterioration of their general condition. Complete pain relief was achieved in 15 of our 25 (59% of patients, and pain reduction was achieved in the remaining 10 (41% patients. The mean duration of pain relief was 7.3 months. Pain recurred in three patients (12% between 2 weeks to 3 months. No major complications occurred. There was transient local pain in most cases, and 2 cases of venous injection of cement without clinical consequences. Conclusion Percutaneous acetabuloplasty is effective in improving the quality of life of patients with osteolytic bone tumours, even though the improvement is observed during the first 6 months only. It can be an effective aid to chemo- and radiotherapy in the management of acetabular metastases.

Evaluation of articular cartilage following rotational acetabular osteotomy for hip dysplasia using T2 mapping MRI.

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Shoji, Takeshi; Yamasaki, Takuma; Izumi, Soutaro; Sawa, Mikiya; Akiyama, Yuji; Yasunaga, Yuji; Adachi, Nobuo

2018-04-27

Rotational acetabular osteotomy (RAO) is one of the surgical treatments for acetabular dysplasia, and satisfactory results have been reported. We evaluated the postoperative changes of articular cartilage and whether the pre-operative condition of the articular cartilage influences the clinical results using T2 mapping MRI. We reviewed 31 hips with early stage osteoarthritis in 31 patients (mean age, 39.6 years), including three men and 28 women who underwent RAO for hip dysplasia. Clinical evaluations including Japanese Orthopedic Association (JOA) score and Japanese Orthopedic Association Hip Disease Evaluation Questionnaire (JHEQ), and radiographical evaluations on X-ray were performed. Longitudinal qualitative assessment of articular cartilage was also performed using 3.0-T MRI with T2 mapping technique preoperatively, 6 months, and at 1 and 2 years postoperatively. There was no case with progression of osteoarthritis. The mean JOA score improved from 70.1 to 93.4 points, the mean postoperative JHEQ score was 68.8 points, and radiographical data also improved postoperatively. We found that the T2 values of the cartilage at both femoral head and acetabulum increased at 6 months on coronal and sagittal views. However, they significantly decreased 1 and 2 years postoperatively. The T2 values of the center to anterolateral region of acetabulum negatively correlated with postoperative JHEQ score, particularly in pain score. This study suggests that biomechanical and anatomical changes could apparently cause decreased T2 values 1-2 years postoperatively compared with those preoperatively. Furthermore, preoperative T2 values of the acetabulum can be prognostic factors for the clinical results of RAO.

The use of customized cages in revision total hip arthroplasty for Paprosky type III acetabular bone defects.

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Mao, Yuanqing; Xu, Chen; Xu, Jiawei; Li, Huiwu; Liu, Fengxiang; Yu, Degang; Zhu, Zhenan

2015-10-01

Revision total hip arthroplasty (THA) is challenging if severe periacetabular bone loss is present. Here we describe a method that uses a customised cage to reconstruct an acetabulum with a massive bone defect. Designed with the aid of the rapid prototyping technique, a customised cage with a hook, crest and flange or braids was made, and then utilized to reconstruct severe compromised acetabulum in revision THA since 2001. Twenty-two patients (23 hips) were included in this study. The mean patient age at the time of surgery was 60.9 years (range, 38-80 years). Three hips had massive acetabular bone defects of Paprosky type IIIA and 20 of type IIIB. The Harris hip score was used to evaluate hip function. Radiographs were taken to evaluate loosening of the cage and resorption of allograft bone. The average follow up was 81.6 ± 24.9 months. The mean Harris hip score improved from 39.6 pre-operatively to 80.9 at the final follow-up. There were no instances of deep infection, severe venous thrombosis, and nerve palsy. One patient who had an intra-operative rupture of the superior acetabular artery was successfully treated using the haemostatic suturing technique. Two patients experienced dislocation at post-operative days four and six, respectively, and both were treated with closed reduction and skin traction for three weeks. The present study demonstrates that a customised cage may be a promising option for THA revision of severely compromised acetabula. Extended follow-up is necessary to evaluate the long-term performance of this approach.

Computer assisted determination of acetabular cup orientation using 2D-3D image registration

International Nuclear Information System (INIS)

Zheng, Guoyan; Zhang, Xuan

2010-01-01

2D-3D image-based registration methods have been developed to measure acetabular cup orientation after total hip arthroplasty (THA). These methods require registration of both the prosthesis and the CT images to 2D radiographs and compute implant position with respect to a reference. The application of these methods is limited in clinical practice due to two limitations: (1) the requirement of a computer-aided design (CAD) model of the prosthesis, which may be unavailable due to the proprietary concerns of the manufacturer, and (2) the requirement of either multiple radiographs or radiograph-specific calibration, usually unavailable for retrospective studies. In this paper, we propose a new method to address these limitations. A new formulation for determination of post-operative cup orientation, which couples a radiographic measurement with 2D-3D image matching, was developed. In our formulation, the radiographic measurement can be obtained with known methods so that the challenge lies in the 2D-3D image matching. To solve this problem, a hybrid 2D-3D registration scheme combining a landmark-to-ray 2D-3D alignment with a robust intensity-based 2D-3D registration was used. The hybrid 2D-3D registration scheme allows computing both the post-operative cup orientation with respect to an anatomical reference and the pelvic tilt and rotation with respect to the X-ray imaging table/plate. The method was validated using 2D adult cadaver hips. Using the hybrid 2D-3D registration scheme, our method showed a mean accuracy of 1.0 ± 0.7 (range from 0.1 to 2.0 ) for inclination and 1.7 ± 1.2 (range from 0.0 to 3.9 ) for anteversion, taking the measurements from post-operative CT images as ground truths. Our new solution formulation and the hybrid 2D-3D registration scheme facilitate estimation of post-operative cup orientation and measurement of pelvic tilt and rotation. (orig.)

Radiographic evaluation of 19 patients with Paprosky 3A and 3B submitted to acetabular review with trabecular metal wedge

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Carlos Eduardo Benvindo Rosal da Fonseca Neto

Full Text Available ABSTRACT Objective: This study is aimed at evaluating the fixation of trabecular metal wedges in patients who underwent revision of total hip arthroplasty with large acetabular bone defects. Methods: The radiographs of 19 patients (21 hips, who underwent revision of total hip arthroplasty using trabecular metal wedges from September 2010 to December 2014 were evaluated. This study included only cases of Paprosky 3A and 3B. Preoperative and postoperative images were analyzed. Non-fixation of the implant was defined by the presence of angular variation of the component higher 10 degrees or displacement greater than 6 mm. Patients with follow-up times of less than 24 months or who did not attend the last two appointments were excluded from the study. Results: The mean follow-up time was 39.4 months (25-61. Fixation was achieved in all cases despite its complexity. There was only one case of dislocation that was treated with open reduction. One case developed infection, and was surgically approached on two occasions, with extensive debridement and intravenous antibiotics following protocol, with good evolution. Conclusion: The implanted trabecular metal wedges showed excellent results in the short- and medium-term and may represent another option in the reconstruction of large acetabular defects, sometimes replacing bone reconstruction that uses bone tissue banks or autologous graft.

Modifier 22 for acetabular fractures in morbidly obese patients: does it affect reimbursement?

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Bergin, Patrick F; Kneip, Christopher; Pierce, Christine; Hendrix, Stephen T; Porter, Scott E; Graves, Matthew L; Russell, George V

2014-11-01

Modifier 22 in the American Medical Association's Current Procedural Terminology (CPT®) book is a billing code for professional fees used to reflect an increased amount of skill, time, and work required to complete a procedure. There is little disagreement that using this code in the setting of surgery for acetabulum fractures in the obese patient is appropriate; however, to our knowledge, the degree to which payers value this additional level of complexity has not been determined. We asked whether (1) the use of Modifier 22 increased reimbursements in morbidly obese patients and (2) there was any difference between private insurance and governmental payer sources in treatment of Modifier 22. Over a 4-year period, we requested immediate adjudication with payers when using Modifier 22 for morbidly obese patients with acetabular fractures. We provided payers with evidence of the increased time and effort required in treating this population. Reimbursements were calculated for morbidly obese and nonmorbidly obese patients. Of the 346 patients we reviewed, 57 had additional CPT® codes or modifiers appended to their charges and were excluded, leaving 289 patients. Thirty (10%) were morbidly obese and were billed with Modifier 22. Fifty-three (18%) were insured by our largest private insurer and 69 (24%) by governmental programs (Medicare/Medicaid). Eight privately insured patients (15%) and seven governmentally insured patients (10%) were morbidly obese and were billed with Modifier 22. For our primary question, we compared reimbursement rates between patients with and without Modifier 22 for obesity within the 289 patients. We then performed the same comparison for the 53 privately insured patients and the 69 governmentally insured patients. Overall, there was no change in mean reimbursement when using Modifier 22 in morbidly obese patients, compared to nonmorbidly obese patients (USD 2126 versus USD 2149, p Level IV, economic and decision analyses. See Instructions

The principle of low frictional torque in the Charnley total hip replacement.

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Wroblewski, B M; Siney, P D; Fleming, P A

2009-07-01

The design of the Charnley total hip replacement follows the principle of low frictional torque. It is based on the largest possible difference between the radius of the femoral head and that of the outer aspect of the acetabular component. The aim is to protect the bone-cement interface by movement taking place at the smaller radius, the articulation. This is achieved in clinical practice by a 22.225 mm diameter head articulating with a 40 mm or 43 mm diameter acetabular component of ultra-high molecular weight polyethylene. We compared the incidence of aseptic loosening of acetabular components with an outer diameter of 40 mm and 43 mm at comparable depths of penetration with a mean follow-up of 17 years (1 to 40). In cases with no measurable wear none of the acetabular components were loose. With increasing acetabular penetration there was an increased incidence of aseptic loosening which reflected the difference in the external radii, with 1.5% at 1 mm, 8.8% at 2 mm, 9.7% at 3 mm and 9.6% at 4 mm of penetration in favour of the larger 43 mm acetabular component. Our findings support the Charnley principle of low frictional torque. The level of the benefit is in keeping with the predicted values.

The choice of surgical approach in the treatment of two-column acetabular fractures

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A. A. Grin’

2014-01-01

Full Text Available The study aimed a comparison of treatment results in patients with two-column acetabular fractures (AO, Type C when using different operative approaches: ilioinguinal (12, Y-type (16 and a combination of posterior-lateral and ilioinguinal approaches (3. Surgical treatment was carried out not later than 3 weeks after injury. The joint congruence was reached in all the cases. The operative time, blood loss, complications, long-term results of treatment were evaluated. The study showed the effectiveness of ilioinguinal approach in case of the simple two-column fractures. When treating patients with complex fractures of the anterior column, the authors found no significant difference in operative time and intraoperative blood loss between the cases of V-type and combined approaches. In patients with two-column fractures accompanied with posterior wall lesion the time of surgery was significantly lower when using the Y-shaped approach as against the two different approaches.

Similar Prevalence of Acetabular Labral Tear in Professional Ballet Dancers and Sporting Participants.

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Mayes, Susan; Ferris, April-Rose; Smith, Peter; Garnham, Andrew; Cook, Jill

2016-07-01

To compare the prevalence of acetabular labral tear in male and female professional ballet dancers with age-matched and sex-matched sporting participants and to determine the relationship to clinical findings and cartilage defects. Case-control study. Clinical and radiology practices. Forty-nine (98 hips) male and female professional ballet dancers (current and retired) with median age 30 years (range: 19-64 years) and 49 (98 hips) age-matched and sex-matched sporting participants. Group (ballet or sports), sex, age, hip cartilage defects, history of hip pain, Hip and Groin Outcome Score, passive hip internal rotation (IR), and external rotation range of movement (ROM). Labral tear identified with 3T magnetic resonance imaging (MRI). Labral tears were identified in 51% of all 196 hips. The prevalence did not differ significantly between the ballet and sporting participants (P = 0.41) or between sexes (P = 0.34). Labral tear was not significantly associated with clinical measures, such as pain and function scores or rotation ROM (P > 0.01 for all). Pain provocation test using IR at 90° of hip flexion had excellent specificity [96%, 95% confidence intervals (CIs), 0.77%-0.998%] but poor sensitivity (50%, 95% CI, 0.26%-0.74%) for identifying labral tear in participants reporting hip pain. Older age and cartilage defect presence were independently associated with an increased risk of labral tear (both P ballet dancers was similar to a sporting population. Labral tears were not associated with clinical findings but were related to cartilage defects, independent of aging. Caution is required when interpreting MRI findings as labral tear may not be the source of the ballet dancer's symptoms.

The diagnostic value of direct CT arthrography using MDCT in the evaluation of acetabular labral tear: with arthroscopic correlation

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Ha, Yong-Chan; Kim, Jae Yoon [Chung-Ang University College of Medicine, Department of Orthopaedic Surgery, Seoul (Korea, Republic of); Choi, Jung-Ah; Lee, Guen Young; Kang, Heung Sik [Seoul National University Bundang Hospital, Departments of Radiology, Seoul National University College of Medicine, 166 Gumi-ro, Bundang-gu, Seongnam (Korea, Republic of); Lee, Young-Kyun; Koo, Kyung-Hoi [Seoul National University Bundang Hospital, Orthopaedic Surgery, Seoul National University College of Medicine, Seongnam (Korea, Republic of)

2013-05-15

The purpose of this study was first, to determine the sensitivity, specificity, and accuracy of MDCT arthrography (CTA) for the diagnosis of acetabular labral tear and sulcus; second, to correlate tear types using the Lage classification system on CTA compared with the arthroscopic classification; and third, to correlate CTA localization with arthroscopic localization. Direct CTA was performed using 16- or 64-slice MDCT in 126 hips (124 patients) who had chronic groin pain and positive impingement test. Images were reviewed and evaluated by two experienced musculoskeletal radiologists preoperatively. CTA findings were compared with arthroscopic findings in 58 hips (56 patients) under consensus by two orthopedic surgeons. Forty-one of the 58 hips were diagnosed as labral tears on CT arthrography. Forty-three of the 58 hips were shown to have a labral tear on arthroscopy. Sensitivity, specificity, and accuracy for detecting labral tear and sulcus by CTA were 90.7%, 86.7%, and 89.7%, and 93.8%, 97.6% and 96.6% respectively for observer 1, and 90.7% and 80.0%, 87.9% and 87.5%, 95.2%, and 93.1 % respectively for observer 2. Thirty-five out of 41 hips (85%) that were diagnosed with labral tear on CTA correlated substantially with arthroscopic Lage classification (kappa coefficient = 0.65). CTA and arthroscopic findings showed similar distribution patterns of the tears with most lesions located in antero- and postero-superior areas (p = 0.013). Direct CT arthrography using MDCT may be a useful diagnostic technique in the detection of acetabular labral tear. (orig.)

Investigation of Larger Poly(α-Methylstyrene) Mandrels for High Gain Designs Using Microencapsulation

International Nuclear Information System (INIS)

Takagi, Masaru; Cook, Robert; McQuillan, Barry; Gibson, Jane; Paguio, Sally

2004-01-01

In recent years we have demonstrated that 2-mm-diameter poly(α-methylstyrene) mandrels meeting indirect drive NIF surface symmetry specifications can be produced using microencapsulation methods. Recently higher gain target designs have been introduced that rely on frequency doubled (green) laser energy and require capsules up to 4 mm in diameter, nominally meeting the same surface finish and symmetry requirements as the existing 2-mm-diameter capsule designs. Direct drive on the NIF also requires larger capsules. In order to evaluate whether the current microencapsulation-based mandrel fabrication techniques will adequately scale to these larger capsules, we have explored extending the techniques to 4-mm-diameter capsules. We find that microencapsulated shells meeting NIF symmetry specifications can be produced, the processing changes necessary to accomplish this are presented here

CT false-profile view of the hip: a reproducible method of measuring anterior acetabular coverage using volume CT data

International Nuclear Information System (INIS)

Needell, Steven D.; Borzykowski, Ross M.; Carreira, Dominic S.; Kozy, John

2014-01-01

To devise a simple, reproducible method of using CT data to measure anterior acetabular coverage that results in values analogous to metrics derived from false-profile radiographs. Volume CT images were used to generate simulated false-profile radiographs and cross-sectional false-profile views by angling a multiplanar reformat 115 through the affected acetabulum relative to a line tangential to the posterior margin of the ischial tuberosities. The anterolateral margin of the acetabulum was localized on the CT false-profile view corresponding with the cranial opening of the acetabular roof. Anterior center edge angle (CEA) was measured between a vertical line passing through the center of the femoral head and a line connecting the center of the femoral head with the anterior edge of the condensed line of the acetabulum (sourcil). Anterior CEA values measured on CT false-profile views of 38 symptomatic hips were compared with values obtained on simulated and projection false-profile radiographs. The CT false-profile view produces a cross-sectional image in the same obliquity as false-profile radiographs. Anterior CEA measured on CT false-profile views were statistically similar to values obtained with false-profile radiographs. CT technologists quickly mastered the technique of generating this view. Inter-rater reliability indicated this method to be highly reproducible. The CT false-profile view is simple to generate and anterior CEA measurements derived from it are similar to those obtained using well-positioned false-profile radiographs. Utilization of CT to assess hip geometry enables precise control of pelvic inclination, eliminates projectional errors, and minimizes limitations of image quality inherent to radiography. (orig.)

CT false-profile view of the hip: a reproducible method of measuring anterior acetabular coverage using volume CT data

Energy Technology Data Exchange (ETDEWEB)

Needell, Steven D.; Borzykowski, Ross M. [Boca Radiology Group, Boca Raton, FL (United States); Carreira, Dominic S.; Kozy, John [Broward Health Orthopedics and Sports Medicine, Fort Lauderdale, FL (United States)

2014-11-15

To devise a simple, reproducible method of using CT data to measure anterior acetabular coverage that results in values analogous to metrics derived from false-profile radiographs. Volume CT images were used to generate simulated false-profile radiographs and cross-sectional false-profile views by angling a multiplanar reformat 115 through the affected acetabulum relative to a line tangential to the posterior margin of the ischial tuberosities. The anterolateral margin of the acetabulum was localized on the CT false-profile view corresponding with the cranial opening of the acetabular roof. Anterior center edge angle (CEA) was measured between a vertical line passing through the center of the femoral head and a line connecting the center of the femoral head with the anterior edge of the condensed line of the acetabulum (sourcil). Anterior CEA values measured on CT false-profile views of 38 symptomatic hips were compared with values obtained on simulated and projection false-profile radiographs. The CT false-profile view produces a cross-sectional image in the same obliquity as false-profile radiographs. Anterior CEA measured on CT false-profile views were statistically similar to values obtained with false-profile radiographs. CT technologists quickly mastered the technique of generating this view. Inter-rater reliability indicated this method to be highly reproducible. The CT false-profile view is simple to generate and anterior CEA measurements derived from it are similar to those obtained using well-positioned false-profile radiographs. Utilization of CT to assess hip geometry enables precise control of pelvic inclination, eliminates projectional errors, and minimizes limitations of image quality inherent to radiography. (orig.)

Deformation of the Durom acetabular component and its impact on tribology in a cadaveric model--a simulator study.

Science.gov (United States)

Liu, Feng; Chen, Zhefeng; Gu, Yanqing; Wang, Qing; Cui, Weiding; Fan, Weimin

2012-01-01

Recent studies have shown that the acetabular component frequently becomes deformed during press-fit insertion. The aim of this study was to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the Durom large head metal-on-metal (MOM) total hips in simulators. Six Durom cups impacted into reamed acetabula of fresh cadavers were used as the experimental group and another 6 size-paired intact Durom cups constituted the control group. All 12 Durom MOM total hips were put through a 3 million cycle (MC) wear test in simulators. The 6 cups in the experimental group were all deformed, with a mean deformation of 41.78 ± 8.86 µm. The average volumetric wear rate in the experimental group and in the control group in the first million cycle was 6.65 ± 0.29 mm(3)/MC and 0.89 ± 0.04 mm(3)/MC (t = 48.43, p = 0.000). The ion levels of Cr and Co in the experimental group were also higher than those in the control group before 2.0 MC. However there was no difference in the ion levels between 2.0 and 3.0 MC. This finding implies that the non-modular acetabular component of Durom total hip prosthesis is likely to become deformed during press-fit insertion, and that the deformation will result in increased volumetric wear and increased ion release. This study was determined to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the prosthesis. Deformation of the cup after implantation increases the wear of MOM bearings and the resulting ion levels. The clinical use of the Durom large head prosthesis should be with great care.

A very rare case with neglected hip dislocation coexisted with posterior acetabular lip fracture

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Samet Karabulut

2011-06-01

Full Text Available Neglected hip dislocation is a rare situation among children. The coexistence of acetabulum fracture is less common. The result of treatment depends on the time of diagnosis. Early treatment is mandatory in such cases. Seven years old female brought to our outpatient clinic with the complaints of right hip pain and walking difficulty. Her parents said that she had fallen from a horse one month ago. X-ray and CT showed a posterior dislocation of her right hip and a fracture on her right posterior acetabular lip. We performed an open reduction via posterior approach. Because the hip was unstable we fixed the femoral head to the acetabulum by a Kirshner wire. Pelvipedal cast was applied after the operation for 6 weeks. After 6 months avascular necrosis (AVN developed on her right femoral head, the range of motion (ROM of the hip was restricted and she had minimal pain on her right hip. J Clin Exp Invest 2011;2(2:228-31

Transfer of metallic debris from the metal surface of an acetabular cup to artificial femoral heads by scraping: comparison between alumina and cobalt-chrome heads.

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Chang, Chong Bum; Yoo, Jeong Joon; Song, Won Seok; Kim, Deug Joong; Koo, Kyung-Hoi; Kim, Hee Joong

2008-04-01

We aimed to investigate the transfer of metal to both ceramic (alumina) and metal (cobalt-chrome) heads that were scraped by a titanium alloy surface under different load conditions. The ceramic and metal heads for total hip arthroplasties were scraped by an acetabular metal shell under various loads using a creep tester. Microstructural changes in the scraped area were visualized with a scanning electron microscope, and chemical element changes were assessed using an energy dispersive X-ray spectrometry. Changes in the roughness of the scraped surface were evaluated by a three-dimensional surface profiling system. Metal transfer to the ceramic and metal heads began to be detectable at a 10 kg load, which could be exerted by one-handed force. The surface roughness values significantly increased with increasing test loads in both heads. When the contact force increased, scratching of the head surface occurred in addition to the transfer of metal. The results documented that metallic debris was transferred from the titanium alloy acetabular shell to both ceramic and metal heads by minor scraping. This study suggests that the greatest possible effort should be made to protect femoral heads, regardless of material, from contact with metallic surfaces during total hip arthroplasty.

Correction of radiographic measurements of acetabular cup wear for variations in pelvis orientation.

Science.gov (United States)

Derbyshire, Brian

2018-03-01

Radiographic measurement of two-dimensional acetabular cup wear is usually carried out on a series of follow-up radiographs of the patient's pelvis. Since the orientation of the pelvis might not be consistent at every X-ray examination, the resulting change in view of the wear plane introduces error into the linear wear measurement. This effect is amplified on some designs of cup in which the centre of the socket is several millimetres below the centre of the cup or circular wire marker. This study describes the formulation of a mathematical method to correct radiographic wear measurements for changes in pelvis orientation. A mathematical simulation of changes in cup orientation and wear vectors caused by pelvic tilt was used to confirm that the formulae corrected the wear exactly if the radiographic plane of the reference radiograph was parallel to the true plane of wear. An error analysis showed that even when the true wear plane was not parallel to the reference radiographic plane, the formulae could still provide a useful correction. A published correction formula was found to be ineffective.

A Feasibility Study into the Use of Three-Dimensional Printer Modelling in Acetabular Fracture Surgery

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A. W. Yu

2015-01-01

Full Text Available There are a number of challenges associated with the operative treatment of acetabular fractures. The approach used is often extensive, while operative time and perioperative blood loss can also be significant. With the proliferation of 3D printer technology, we present a fast and economical way to aid the operative planning of complex fractures. We used augmented stereoscopic 3D CT reconstructions to allow for an appreciation of the normal 3D anatomy of the pelvis on the fractured side and to use the models for subsequent intraoperative contouring of pelvic reconstruction plates. This leads to a reduction in the associated soft tissue trauma, reduced intraoperative time and blood loss, minimal handling of the plate, and reduced fluoroscopic screening times. We feel that the use of this technology to customize implants, plates, and the operative procedure to a patient’s unique anatomy can only lead to improved outcomes.

[Pelvic reconstructions after bone tumor resection].

Science.gov (United States)

Anract, Philippe; Biau, David; Babinet, Antoine; Tomeno, Bernard

2014-02-01

The three more frequent primitive malignant bone tumour which concerned the iliac bone are chondrosarcoma, following Ewing sarcoma and osteosarcoma. Wide resection remains the most important part of the treatment associated with chemotherapy for osteosarcoma and the Ewing sarcoma. Iliac wing resections and obdurate ring don't required reconstruction. However, acetabular resections and iliac wing resection with disruption of the pelvic ring required reconstruction to provide acceptable functional result. Acetabular reconstruction remains high technical demanding challenge. After isolated acetabular resection or associated to obdurate ring, our usual method of reconstruction is homolateral proximal femoral autograft and total hip prosthesis but it is possible to also used : saddle prosthesis, Mac Minn prosthesis with auto or allograft, modular prosthesis or custom made prosthesis, massive allograft with or without prosthesis and femoro-ilac arthrodesis. After resection of the iliac wing plus acetabulum, reconstruction can be performed by femoro-obturatrice and femora-sacral arthrodesis, homolateral proximal femoral autograft and prosthesis, femoral medialisation, massive allograft and massive allograft. Carcinological results are lesser than resection for distal limb tumor, local recurrence rate range 17 to 45%. Functional results after Iliac wing and obdurate ring are good. However, acetabular reconstruction provide uncertain functional results. The lesser results arrive after hemipelvic or acetabular and iliac wing resection-reconstruction, especially when gluteus muscles were also resected. The most favourable results arrive after isolated acetabular or acetabular plus obturateur ring resection-reconstruction.

[Recostruction of Extensive Acetabular Defects by Bioactive Glass Ceramics in Re-operations of Total Endoprostheses.].

Science.gov (United States)

Urban, K; Sponer, P

1998-01-01

The authors made 37 revisions on account of aseptic loosening of total endoprostheses of the hip joint using bioactive glass ceramics BAS-0 of Lasak Co. Prague. For reconstruction of large defects of the acetabulum they used a combination of different types of anti-protrusion metal baskets and granules from this material. In some instances the glass ceramic material was combined with autologous spongiosa. The longest follow-up period is over 4 years. In no instance loosening of the glass ceramic material occurred or its expulsion. All reconstructed sockets of hip joints were burdened by the patients from the third month after surgery. Harris Hip Score before operation was on average 52. During the last checkups of the patients it reached the level of 86. The authors mention complications associated with the procedure. The advantages and disadvantages of the procedure are discussed. Key words: bioactive glass ceramics, reconstruction of acetabular defect, aseptic loosening of endoprosthesis.

Deformation of the Durom acetabular component and its impact on tribology in a cadaveric model--a simulator study.

Directory of Open Access Journals (Sweden)

Feng Liu

Full Text Available BACKGROUND: Recent studies have shown that the acetabular component frequently becomes deformed during press-fit insertion. The aim of this study was to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the Durom large head metal-on-metal (MOM total hips in simulators. METHODS: Six Durom cups impacted into reamed acetabula of fresh cadavers were used as the experimental group and another 6 size-paired intact Durom cups constituted the control group. All 12 Durom MOM total hips were put through a 3 million cycle (MC wear test in simulators. RESULTS: The 6 cups in the experimental group were all deformed, with a mean deformation of 41.78 ± 8.86 µm. The average volumetric wear rate in the experimental group and in the control group in the first million cycle was 6.65 ± 0.29 mm(3/MC and 0.89 ± 0.04 mm(3/MC (t = 48.43, p = 0.000. The ion levels of Cr and Co in the experimental group were also higher than those in the control group before 2.0 MC. However there was no difference in the ion levels between 2.0 and 3.0 MC. CONCLUSIONS: This finding implies that the non-modular acetabular component of Durom total hip prosthesis is likely to become deformed during press-fit insertion, and that the deformation will result in increased volumetric wear and increased ion release. CLINICAL RELEVANCE: This study was determined to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the prosthesis. Deformation of the cup after implantation increases the wear of MOM bearings and the resulting ion levels. The clinical use of the Durom large head prosthesis should be with great care.

Short-term survival of the trabecular metal cup is similar to that of standard cups used in acetabular revision surgery.

Science.gov (United States)

Mohaddes, Maziar; Rolfson, Ola; Kärrholm, Johan

2015-02-01

The use of trabecular metal (TM) cups in revision surgery has increased worldwide during the last decade. Since the introduction of the TM cup in Sweden in 2006, this design has gradually replaced other uncemented designs used in Sweden. According to data from the Swedish Hip Arthroplasty Register (SHAR) in 2012, one-third of all uncemented first-time cup revisions were performed using a TM cup. We compared the risk of reoperation and re-revision for TM cups and the 2 other most frequently used cup designs in acetabular revisions reported to the SHAR. The hypothesis was that the performance of TM cups is as good as that of established designs in the short term. The study population consisted of 2,384 patients who underwent 2,460 revisions during the period 2006 through 2012. The most commonly used cup designs were the press-fit porous-coated cup (n = 870), the trabecular metal cup (n = 805), and the cemented all-polyethylene cup (n = 785). 54% of the patients were female, and the median age at index revision was 72 (19-95) years. Reoperation was defined as a second surgical intervention, and re-revision-meaning exchange or removal of the cup-was used as endpoint. The mean follow-up time was 3.3 (0-7) years. There were 215 reoperations, 132 of which were re-revisions. The unadjusted and adjusted risk of reoperation or re-revision was not significantly different for the TM cup and the other 2 cup designs. Our data support continued use of TM cups in acetabular revisions. Further follow-up is necessary to determine whether trabecular metal cups can reduce the re-revision rate in the long term, compared to the less costly porous press-fit and cemented designs.

Efficient radiologic diagnosis of pelvic and acetabular trauma; Rationelle bildgebende Diagnostik von Becken- und Azetabulumverletzungen

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Kreitner, K.F.; Mildenberger, P.; Thelen, M. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Rommens, P.M. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Unfallchirurgie

2000-01-01

In spite of the widespread availability of CT scanners, conventional X-ray radiographs remain the basic imaging modality in patients with pelvic and/or acetabular trauma. However, the extent of their use will depend on local utilities (e.g., availability of CT scanners) and on the patient's clinical condition. Regarding the inaccuracy of conventional radiography in the diagnosis of injuries of the dorsal pelvic ring and of the acetabulum, computed tomography represents the most important imaging modality in the clinically stable patient. CT provides an exact staging of the extent of trauma and allows for differentiation of pelvic instabilities. CT clearly demonstrates the severity of acetabular trauma and is superior in the detection of local complicating factors, i.e., impressions fractures and (sub-)luxations of the femoral head as well as free intraarticular fragments. CT findings provide the basis for definite treatment regimens of the injured patient. By extension of the examination, all relevant organs and systems (craniospinal, cardiovascular, gastrointestinal, respiratory, genitourinary) can be imaged during one session. The speed of spiral CT scanners and their diagnostic accuracy will play a major role in the management of, especially, polytraumatized patients. The indication for angiography with the option of therapeutic embolization exists if a pelvic bleeding persists even after reposition and operative fixation of the injury. (orig.) [German] Bei der Klaerung einer Verletzung des Beckens oder des Azetabulums stellen konventionelle Uebersichtsaufnahmen weiterhin die Basis der bildgebenden Diagnostik dar. Art und Umfang werden bestimmt von lokalen Gegebenheiten (z.B. Verfuegbarkeit von CT-Geraeten) sowie vom klinischen Zustand des Patienten. Aufgrund der diagnostischen Ungenauigkeit der konventionellen Roentgendiagnostik gerade im Bereich des stabilitaetsbedeutsamen dorsalen Beckenringes und des Azetabulums schliesst sich beim klinisch stabilen

Supra-acetabular line is better than supra-iliac line for coronal balance referencing-a study of perioperative whole spine X-rays in degenerative lumbar scoliosis and ankylosing spondylitis patients.

Science.gov (United States)

Hey, Hwee Weng Dennis; Kim, Cheung-Kue; Lee, Won-Gyu; Juh, Hyung-Suk; Kim, Ki-Tack

2017-12-01

The aim of spinal deformity correction is to restore the spine's functional alignment by balancing it in both the sagittal and coronal planes. Regardless of posture, the ideal coronal profile is straight, and therefore readily assessable. This study compares two radiological methods to determine which better predicts postoperative standing coronal balance. We conducted a single-center, radiographic comparative study between 2011 and 2015. A total of 199 patients with a mean age of 55.1 years were studied. Ninety patients with degenerative lumbar scoliosis (DLS) and 109 ankylosing spondylitis (AS) were treated with posterior surgery during this period. Baseline clinical and radiographic parameters (sagittal and coronal) were recorded. Comparison was performed between the new supra-acetabular line (central sacral vertical line [CSVL1]) and conventional supra-iliac line (CSVL2) perpendicular methods of coronal balance assessment. These methods were also compared with the gold standard standing C7 plumb line. Each patient underwent standardized operative procedures and had perioperative spine X-rays obtained for assessment of spinal balance. Adjusted multivariate analysis was used to determine predictors of coronal balance. Significant differences in baseline characteristics (age, gender, and radiographic parameters) were found between patients with DLS and AS. CSVL1, CSVL2, and C7 plumb line differed in all the perioperative measurements. These three radiological methods showed a mean right coronal imbalance for both diagnoses in all pre-, intra-, and postoperative radiographs. The magnitude of imbalance was the greatest for CSVL2 followed by CSVL1 and subsequently the C7 plumb line. A larger discrepancy between CSVL and C7 plumb line measurements intraoperatively than those postoperatively suggests a postural effect on these parameters, which is greater for CSVL2. Multivariate analysis identified that in DLS, the preoperative C7 plumb line was predictive of its

Radiographic Underestimation of In Vivo Cup Coverage Provided by Total Hip Arthroplasty for Dysplasia.

Science.gov (United States)

Nie, Yong; Wang, HaoYang; Huang, ZeYu; Shen, Bin; Kraus, Virginia Byers; Zhou, Zongke

2018-01-01

The accuracy of using 2-dimensional anteroposterior pelvic radiography to assess acetabular cup coverage among patients with developmental dysplasia of the hip after total hip arthroplasty (THA) remains unclear in retrospective clinical studies. A group of 20 patients with developmental dysplasia of the hip (20 hips) underwent cementless THA. During surgery but after acetabular reconstruction, bone wax was pressed onto the uncovered surface of the acetabular cup. A surface model of the bone wax was generated with 3-dimensional scanning. The percentage of the acetabular cup that was covered by intact host acetabular bone in vivo was calculated with modeling software. Acetabular cup coverage also was determined from a postoperative supine anteroposterior pelvic radiograph. The height of the hip center (distance from the center of the femoral head perpendicular to the inter-teardrop line) also was determined from radiographs. Radiographic cup coverage was a mean of 6.93% (SD, 2.47%) lower than in vivo cup coverage for these 20 patients with developmental dysplasia of the hip (Pcup coverage (Pearson r=0.761, Pcup (P=.001) but not the position of the hip center (high vs normal) was significantly associated with the difference between radiographic and in vivo cup coverage. Two-dimensional radiographically determined cup coverage conservatively reflects in vivo cup coverage and remains an important index (taking 7% underestimation errors and the effect of greater underestimation of larger cup size into account) for assessing the stability of the cup and monitoring for adequate ingrowth of bone. [Orthopedics. 2018; 41(1):e46-e51.]. Copyright 2017, SLACK Incorporated.

Acetabular anteversion is associated with gluteal tendinopathy at MRI

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Moulton, Kyle M. [University of Saskatchewan, Department of Medical Imaging, Saskatoon, SK (Canada); Royal University Hospital, Department of Medical Imaging, Saskatoon, SK (Canada); Aly, Abdel-Rahman [University of Saskatchewan, Department of Physical Medicine and Rehabilitation, Saskatoon, SK (Canada); Rajasekaran, Sathish [Health Pointe - Pain, Spine and Sport Medicine, Edmonton, AB (Canada); Shepel, Michael; Obaid, Haron [University of Saskatchewan, Department of Medical Imaging, Saskatoon, SK (Canada)

2015-01-15

Gluteal tendinopathy and greater trochanteric pain syndrome (GTPS) remain incompletely understood despite their pervasiveness in clinical practice. To date, no study has analyzed the morphometric characteristics of the hip on magnetic resonance imaging (MRI) that may predispose to gluteal tendinopathy. This study aimed to evaluate whether acetabular anteversion (AA), femoral neck anteversion (FNA), and femoral neck-shaft angle (FNSA) are associated with MRI features of gluteal tendinopathy. A total of 203 MRI examinations of the hip met our inclusion and exclusion criteria. A single blinded investigator measured AA, FNA, and FNSA according to validated MRI techniques. Two blinded subspecialty-trained musculoskeletal radiologists then independently evaluated the presence of gluteal tendinosis, trochanteric bursitis, and subgluteal bursitis. Statistical analysis was performed using a one-way analysis of variance (ANOVA; post-hoc Tukey's range test). At MRI, 57 patients had gluteal tendinosis with or without bursitis, 26 had isolated trochanteric bursitis, and 11 had isolated subgluteal bursitis. AA was significantly (p = 0.01) increased in patients with MRI evidence of gluteal tendinosis with or without bursitis [mean: 18.4 , 95 % confidence interval (CI): 17.2 -19.6 ] compared with normal controls (mean: 15.7 , 95 % CI: 14.7 -16.8 ). Similarly, AA was significantly (p = 0.04) increased in patients with isolated trochanteric bursitis (mean: 18.8 , 95 % CI: 16.2 -21.6 ). No association was found between FNA or FNSA and the presence of gluteal tendinopathy. Interobserver agreement for the presence and categorization of gluteal tendinopathy was very good (kappa = 0.859, 95 % CI: 0.815-0.903). Our MRI study suggests that there is an association between increased AA and gluteal tendinopathy, which supports a growing body of evidence implicating abnormal biomechanics in the development of this condition. (orig.)

Acetabular anteversion is associated with gluteal tendinopathy at MRI

International Nuclear Information System (INIS)

Moulton, Kyle M.; Aly, Abdel-Rahman; Rajasekaran, Sathish; Shepel, Michael; Obaid, Haron

2015-01-01

Gluteal tendinopathy and greater trochanteric pain syndrome (GTPS) remain incompletely understood despite their pervasiveness in clinical practice. To date, no study has analyzed the morphometric characteristics of the hip on magnetic resonance imaging (MRI) that may predispose to gluteal tendinopathy. This study aimed to evaluate whether acetabular anteversion (AA), femoral neck anteversion (FNA), and femoral neck-shaft angle (FNSA) are associated with MRI features of gluteal tendinopathy. A total of 203 MRI examinations of the hip met our inclusion and exclusion criteria. A single blinded investigator measured AA, FNA, and FNSA according to validated MRI techniques. Two blinded subspecialty-trained musculoskeletal radiologists then independently evaluated the presence of gluteal tendinosis, trochanteric bursitis, and subgluteal bursitis. Statistical analysis was performed using a one-way analysis of variance (ANOVA; post-hoc Tukey's range test). At MRI, 57 patients had gluteal tendinosis with or without bursitis, 26 had isolated trochanteric bursitis, and 11 had isolated subgluteal bursitis. AA was significantly (p = 0.01) increased in patients with MRI evidence of gluteal tendinosis with or without bursitis [mean: 18.4 , 95 % confidence interval (CI): 17.2 -19.6 ] compared with normal controls (mean: 15.7 , 95 % CI: 14.7 -16.8 ). Similarly, AA was significantly (p = 0.04) increased in patients with isolated trochanteric bursitis (mean: 18.8 , 95 % CI: 16.2 -21.6 ). No association was found between FNA or FNSA and the presence of gluteal tendinopathy. Interobserver agreement for the presence and categorization of gluteal tendinopathy was very good (kappa = 0.859, 95 % CI: 0.815-0.903). Our MRI study suggests that there is an association between increased AA and gluteal tendinopathy, which supports a growing body of evidence implicating abnormal biomechanics in the development of this condition. (orig.)

Predictors for Long-Term Hip Survivorship Following Acetabular Fracture Surgery: Importance of Gap Compared with Step Displacement.

Science.gov (United States)

Verbeek, Diederik O; van der List, Jelle P; Tissue, Camden M; Helfet, David L

2018-06-06

Historically, the greatest residual (gap or step) displacement is used to predict clinical outcome following acetabular fracture surgery. Gap and step displacement may, however, impact the outcome to different degrees. We assessed the individual relationship between gap or step displacement and hip survivorship and determined their independent association with conversion to total hip arthroplasty. Patients who had acetabular fracture fixation (from 1992 through 2014), follow-up of ≥2 years (or early conversion to total hip arthroplasty), and postoperative computed tomography (CT) scans were included. Of 227 patients, 55 (24.2%) had conversion to total hip arthroplasty at a mean follow-up (and standard deviation) of 8.7 ± 5.6 years. Residual gap and step displacement were measured using a standardized CT-based method, and assessors were blinded to the outcome. Kaplan-Meier survivorship curves for the hips were plotted and compared (log-rank test) using critical cutoff values for gap and step displacement. These values were identified using receiver operating characteristic curves. Multivariate analysis was performed to identify independent variables associated with conversion to total hip arthroplasty. Subgroup analysis was performed in younger patients (step displacement. Hip survivorship at 10 years was 82.0% for patients with a gap of step of step of ≥1.0 mm (p = 0.012). A gap of ≥5 mm (hazard ratio [HR], 2.3; p = 0.012) and an age of ≥50 years (HR, 4.2; p step of ≥1 mm (HR, 6.4; p = 0.017) was an independent factor for conversion to total hip arthroplasty. Residual gap and step displacement as measured on CT scans are both related to long-term hip survivorship, but step displacement (1 mm) is tolerated less than gap displacement (5 mm). Of the 2 types of displacement, only a large gap displacement (≥5 mm) was independently associated with conversion to total hip arthroplasty. In younger patients who had less articular impaction with smaller residual

Hip Arthroscopy for Femoral-Acetabular Impingement: Do Active Claims Affect Outcomes?

Science.gov (United States)

Gigi, Roy; Rath, Ehud; Sharfman, Zachary T; Shimonovich, Shachar; Ronen, Itai; Amar, Eyal

2016-04-01

To compare outcomes of 3 patient groups undergoing hip arthroscopy. This study included 138 consecutive hip arthroscopies (106 analyzed) for femoral-acetabular impingement (FAI) with or without labral tear in patients with a minimum 1-year follow-up. Inclusion criteria included patients older than 18 with clinical or radiologic manifestation of FAI with or without labral tear. Exclusion criteria included previous hip surgery and various hip pathologies. Patients were classified into 3 study groups. Group 1 included work-related injuries with active claims ACs (n = 33); mean age, 32 (range, 19 to 63); group 2 included sports injuries with no ACs (n = 35); mean age, 32 (range, 18 to 69); and group 3 included non-sports-related injuries without pending ACs (NAS; n = 38); mean age, 45 (range, 20 to 68). Outcomes were assessed using modified Harris hip scores (mHHS) and hip outcome scores (HOS) preoperatively and during the final evaluation. Baseline score for all groups did not significantly differ (P = .210 for mHHS, P = .176 for HOS). All groups significantly improved from preoperative to final evaluation (group 1: mHHS P = .42, HOS P = .001; group 2: mHHS P arthroscopy. Hip arthroscopy as an intervention in patients with ACs provided positive outcomes, corroborating that an AC is not a contraindication for this procedure. Level III, retrospective comparative study. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

BIOMECHANICAL JUSTIFICATION OF THE THREADED ELEMENT’S FORM OF THE TOTAL HIP ENDOPROSTHESIS’ ACETABULAR COMPONENT

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PANCHENKO S. P.

2017-03-01

Full Text Available Abstract. Formulation of the problem. Total hip replacement (THR remains to be responsible for the markable clinical achievements of contemporal orthopaedic surgery [1; 2; 4]. It should be noted, that numerous efforts to create an “ideal” uncemented hip endoprosthesis’ construction were failed, but led into wide diversity of implants. Such a diversity allowes to individualize implant type selection and to improve implant’s survival and total THR’s clinical outcomes [1; 4]. Outcomes mentioned above determine successful application of total hip replacement as a treatment method. Consequently, development of new and improvement of existing hip endoprosthesis’ constructions seems to be of current interest for contemporal orthopaedic surgery. Purpose. To determine optimal parametres of threaded element’s geometry of total hip endoprosthesis’ threaded acetabular component. Conclusion. There were revealed that threaded element model with right-angled triangle transverse section shape seems to be the most effective considering hardness, while the triangle is leaned on the bone massive with its cathetus. At the same time, results of calculations represent pelvic bone stress-strain state during THR quantitavely and stipulate further research.

Achados em ressonância magnética artrográfica de indivíduos com lesão do labrum acetabular Magnetic resonance arthrographic findings in subjects with acetabular labral tears

Directory of Open Access Journals (Sweden)

André Luiz Almeida Pizzolatti

2011-01-01

Full Text Available OBJETIVO: Descrever os achados em artro RM de sujeitos com suspeita de lesão do labrum acetabular. MÉTODO: Foram analisadas 108 artro RM de quadris em 2007/2008. Dois radiologistas independentemente analisaram as imagens e foi considerada a resposta comum entre eles. Com base em seus pareceres observou-se o local e estadiamento das lesões labrais e condrais, as alterações anatômicas, e a presença de tendinite e bursite trocantérica. RESULTADO: As lesões labrais grau I ocorreram em 41% dos casos, grau II em 31%, e grau III em 29%. O IFA tipo cam foi frequente em 36% dos casos, tipo pincer em 11%, e IFA misto em 13%, nestes casos 57% apresentaram lesão labral grau III, A lesão condral grau I foi observada em 51% acetábulos, as de grau II em 13%, e grau III em 18%. CONCLUSÃO: As alterações morfológicas que provocam IFA do tipo cam foram as mais prevalentes. Em relação ao grau de lesão labral e condral foram predominantes as lesões grau I independente da presença ou do tipo de IFA, exceto em IFAs mistos onde houve predomínio de lesão labral grau III. Não foi observada uma relação entre o grau de lesão labral e condral.OBJECTIVE: To describe the MR arthrographic findings in subjects with suspected acetabular labral tears of the hip. METHOD: 108 hip MRa results were analyzed in 2007-2008. Two radiologists independently interpreted the images, and the consensual answers between them were considered for analysis. Based on their opinions, information was obtained on the location, staging of the chondral and labral lesions, anatomic alterations, and the presence of trochanteric bursitis and tendonitis. RESULTS: 1st degree labral lesions occurred in 41% of cases, 2nd degree in 31%, and 3rd degree in 29%. The cam type FAI was common in 36% of cases, pincer FAI in 11%, and mixed cam-pincer FAI in 13%; in these cases 57% had grade III labral lesions. 1st degree chondral lesions were observed in 51% of acetabulum, 2nd degree in 13

[Misinterpretation of the anteversion in computer-assisted acetabular cup navigation as a result of a simplified palpation method of the frontal pelvic plane].

Science.gov (United States)

Richolt, J A; Rittmeister, M E

2006-01-01

Computer assisted navigation of the acetabular cup in THR requires reliable digitalisation of bony landmarks defining the frontal pelvic plane by user driven palpation. According to the system recommendations the subcutaneous fat should be held aside during epicutaneous digitalization. To improve intraoperative practicability this is often neglected in the symphysis area. In these cases the fat is just compressed and not pushed aside. In this study soft tissue thickness was assessed by ultrasound and pelvic geometry was measured in 72 patients to quantify potential misinterpretation of cup anteversion triggered by the simplified palpation. As reference we employed data of the same patients that had been acquired by recommended palpation. Anteversion misinterpretation averaged at 8.2 degrees with extremes from 2 to 24 degrees. There were no correlations between soft tissue thickness or misinterpretation and body weight, height and pelvic size. Anteversion misinterpretation was highly significant worse compared to the reference data. In 31 % of the patients the anteversion misinterpretation of a navigation system would have been wrong by over 10 degrees and in 81 % over 5 degrees . Therefore the simplified palpation should not be utilized. For epicutaneous digitalization of the bony landmarks it is mandatory to push the subcutaneous fat aside.

Analysis of 18 F-FDG uptake patterns in PET for diagnosis of septic and aseptic loosening after total hip arthroplasty

International Nuclear Information System (INIS)

Cremerius, U.; Niethard, F.U.; Mumme, T.; Reinartz, P.; Wirtz, D.; Buell, U.

2003-01-01

Aim: Identification of typical patterns for fluorodeoxyglucose (FDG) uptake in positron emission tomography (PET) to detect aseptic loosening of hip prosthesis (acetabular and/or femoral component) and prosthetic infection. Methods: 18 patients with painful hip prosthesis underwent PET using a dedicated full ring scanner after application of 200-300 MBq FDG. The interface between bone and surrounding soft tissue or bone as displayed on coronal slices was divided into 12 segments in accordance with the classifications of Delee and Gruen. FDG uptake in each of the segments was scored (0-3) by two independent observers. Intraoperative findings were regarded as the gold standard. Results: After surgical revision 14 acetabular components and 9 femoral components were found to be loose and prosthetic infection was present in 7 prostheses. Loosening of the acetabular component was correlated to enhanced uptake in the middle of the acetabular interface, while loosening of the femoral component was correlated to enhanced uptake in the proximal and middle segment of the lateral femoral interface and the proximal segment of the medial femoral interface. A similar pattern was found in prosthetic infection with high uptake along the middle portion of the lateral femoral interface. In 6 of 7 infected prostheses loosening of the acetabular and of the femoral component was present. Taking the typical uptake patterns as criteria for loosening and grade 3 uptake as an additional criterion for septic loosening the accuracy of PET imaging in the detection of loosening of the acetabular or the femoral component and of prosthetic infection was 72, 78 and 89%, respectively. Conclusion: This pilot study presents FDG-PET as a promising diagnostic tool for patients with painful hip prostheses. Its clinical value should be evaluated in a larger patient population. (orig.) [de

Lack of consensus on optimal acetabular cup orientation because of variation in assessment methods in total hip arthroplasty: a systematic review.

Science.gov (United States)

Snijders, Thom E; Willemsen, Koen; van Gaalen, Steven M; Castelein, Rene M; Weinans, Harrie; de Gast, Arthur

2018-05-01

Dislocation is one of the main reasons for revision of total hip arthroplasty but dislocation rates have not changed in the past decades, compromising patients' well-being. Acetabular cup orientation plays a key role in implant stability and has been widely studied. This article investigates whether there is a consensus on optimal cup orientation, which is necessary when using a navigation system. A systematic search of the literature in the PubMed, Embase and Cochrane databases was performed (March 2017) to identify articles that investigated the direct relationship between cup orientation and dislocation, including a thorough evaluation of postoperative cup orientation assessment methods. Twenty eight relevant articles evaluating a direct relation between dislocation and cup orientation could not come to a consensus. The key reason is a lack of uniformity in the assessment of cup orientation. Cup orientation is assessed with different imaging modalities, different methodologies, different definitions for inclination and anteversion, several reference planes and distinct patient positions. All available studies lack uniformity in cup orientation assessment; therefore it is impossible to reach consensus on optimal cup orientation. Using navigation systems for placement of the cup is inevitably flawed when using different definitions in the preoperative planning, peroperative placement and postoperative evaluation. Further methodological development is required to assess cup orientation. Consequently, the postoperative assessment should be uniform, thus differentiating between anterior and posterior dislocation, use the same definitions for inclination and anteversion with the same reference plane and with the patient in the same position.

The design of the acetabular component and size of the femoral head influence the risk of revision following 34 721 single-brand cemented hip replacements: a retrospective cohort study of medium-term data from a National Joint Registry.

Science.gov (United States)

Jameson, S S; Baker, P N; Mason, J; Gregg, P J; Brewster, N; Deehan, D J; Reed, M R

2012-12-01

Despite excellent results, the use of cemented total hip replacement (THR) is declining. This retrospective cohort study records survival time to revision following primary cemented THR using the most common combination of components that accounted for almost a quarter of all cemented THRs, exploring risk factors independently associated with failure. All patients with osteoarthritis who had an Exeter V40/Contemporary THR (Stryker) implanted before 31 December 2010 and recorded in the National Joint Registry for England and Wales were included in the analysis. Cox's proportional hazard models were used to analyse the extent to which risk of revision was related to patient, surgeon and implant covariates, with a significance threshold of p brand of cement/presence of antibiotic, femoral head material (stainless steel/alumina) and stem taper size/offset. However, the risk of revision for dislocation was significantly higher with a 'plus' offset head (HR 2.05, p = 0.003) and a hooded acetabular component (HR 2.34, p designs of acetabular component and sizes of femoral head after adjustment for a range of covariates.

Does surface roughness influence the primary stability of acetabular cups? A numerical and experimental biomechanical evaluation.

Science.gov (United States)

Le Cann, Sophie; Galland, Alexandre; Rosa, Benoît; Le Corroller, Thomas; Pithioux, Martine; Argenson, Jean-Noël; Chabrand, Patrick; Parratte, Sébastien

2014-09-01

Most acetabular cups implanted today are press-fit impacted cementless. Anchorage begins with the primary stability given by insertion of a slightly oversized cup. This primary stability is key to obtaining bone ingrowth and secondary stability. We tested the hypothesis that primary stability of the cup is related to surface roughness of the implant, using both an experimental and a numerical models to analyze how three levels of surface roughness (micro, macro and combined) affect the primary stability of the cup. We also investigated the effect of differences in diameter between the cup and its substrate, and of insertion force, on the cups' primary stability. The results of our study show that primary stability depends on the surface roughness of the cup. The presence of macro-roughness on the peripheral ring is found to decrease primary stability; there was excessive abrasion of the substrate, damaging it and leading to poor primary stability. Numerical modeling indicates that oversizing the cup compared to its substrate has an impact on primary stability, as has insertion force. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

Results of Chiari pelvic osteotomy for acetabular dysplasia in adults; Association with bone scintigraphic findings

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Nakamura, Nobuo; Ozono, Kenji; Sugano, Nobuhiko; Takaoka, Kunio; Ono, Hiroo (Osaka Univ. (Japan). Faculty of Medicine)

1993-02-01

In an attempt to determine indications of Chiari pelvic osteotomy in acetabular dysplasia, postoperative outcome of hip joint (64 joints) was examined on the basis of findings of bone scintigraphy. The subjects were 61 patients with osteoarthrosis of hip joint who underwent preoperative bone scintigraphy. The follow-up period ranged from 2 years to 9 years and 7 months with a mean of 4 years and 9 months. According to X-ray findings, 37 osteoarthrosis joints were staged as early and 27 as progressive. Preoperative bone scintigraphic findings fell into three: (I) normal or slight hot type (33 joints), (II) hot type at the weighting part (16 joints), and (III) double hot type in the weighting part and inside part (15 joints). None of the patients had severe surgical complications such as deep-seated infection, neuroparalysis and pseudojoint. According to the clinical staging for hip joint function, 7 (47%) of 64 joints were judged as poor after osteotomy, belonging to type III. Deterioration of osteoarthrosis was seen in 11 joints (41%) on X-ray films. Of these, 9 had type III. In conclusion, Chiari pelvic osteotomy should not be indicated when type III is shown on bone scintigrams. (N.K.).

Restauração do centro de rotação na artroplastia total do quadril minimamente invasiva Restoration of the rotation center in minimally-invasive total hip replacement

Directory of Open Access Journals (Sweden)

José Ricardo Negreiros Vicente

2009-01-01

center as well as a good positioning of the acetabular component when using the minimally-invasive posterior approach for uncemented total hip replacement. METHODS: In a comparative non-random prospective study, 64 adult patients underwent elective total hip arthroplasty using the minimally-invasive posterior approach performed by one single surgeon. All patients included in this study had a superior and lateral migration of the rotation center of the hip in comparison to the normal contralateral hip. Patients were excluded from the study if they presented the following: diagnosis of femoral neck fracture, displasic hip types 2, 3 and 4 (Crowe's classification, osteoarthritis of the contralateral hip. Of the 64 patients in the study, 39 had a radiographic pre-op acetabular size planning equal or less than 50 mm and 25 patients had a radiographic pre-op acetabular size planning equal or more than 52 mm. We considered a good result the following goals: acetabular bend between 35 and 50 degrees, acetabular size according to the pre-op estimative with full contact in the three zones of DeLee-Charnley , a lower medial and vertical positioning of the rotation center in comparison with the pre-op values and a final limb discrepancy lower than 10 mm. RESULTS: A better restoration of the rotation center, as well as, excellent acetabular positioning was found in patients with smaller acetabular size (equal or less than 50, p=0, 04. We must draw attention to two risks when using the minimally-invasive posterior approach: a vertical acetabular position and a lateral position of the acetabular component increasing the risk of a poor contact in the zone 1 due to an insufficient reaming of the medial acetabular host bone. CONCLUSION: We propose standard surgical approaches in patients with larger anatomical measurements (acetabular planning size more than 50.

Pelvic and acetabular trauma care in Ireland: the past, present and future

LENUS (Irish Health Repository)

Queally, JM

2017-08-01

Pelvic injuries involve injury to the osseo-ligamentous ring structure of the pelvis or the acetabulum of either hip joint. They are typically caused by high-energy trauma and may be associated with significant morbidity or mortality at the time of injury due to excessive haemorrhage and associated abdominal, chest or head injuries with mortality rates of 8.6% to 19.1% reported for closed injuries and rates of up to 50% reported for open injuries1. Despite the severity of these injuries and the potential for poor long term outcomes, these injuries were managed with non-surgical treatment until the middle of the 20th century. Treatment typically involved prolonged bed rest, traction or compression devices, pelvic slings and spica casts with poor outcomes due to persistent pelvic deformity in pelvic injures and early osteoarthritis in acetabular fractures2,3. In the 1930’s, with the advent of radiography, significant progress was made in terms of understanding injury patterns, subsequent displacement and the significance of pelvic instability and deformity post injury. Along with the improved definitive management of pelvic injuries, similar progress was made with the immediate management of life-threatening haemodynamic instability and resuscitation with a significant improvement in mortality rate achieved over the past 50 years3,4. In contemporary trauma care, to ensure optimal outcomes, pelvic trauma is now considered a subspecialty practised in tertiary centres by fellowship trained specialists. Herein we describe the evolution of pelvic trauma care in Ireland over the past 30 years in an overall context of improved international paradigms of care and discuss potential future developments

Surgical planning of total hip arthroplasty: accuracy of computer-assisted EndoMap software in predicting component size

International Nuclear Information System (INIS)

Davila, Jesse A.; Kransdorf, Mark J.; Duffy, Gavan P.

2006-01-01

The purpose of our study was to assess the accuracy of a computer-assisted templating in the surgical planning of patients undergoing total hip arthroplasty utilizing EndoMap software (Siemans AG, Medical Solutions, Erlangen, Germany). Endomap Software is an electronic program that uses DICOM images to analyze standard anteroposterior radiographs for determination of optimal prosthesis component size. We retrospectively reviewed the preoperative radiographs of 36 patients undergoing uncomplicated primary total hip arthroplasty, utilizing EndoMap software, Version VA20. DICOM anteroposterior radiographs were analyzed using standard manufacturer supplied electronic templates to determine acetabular and femoral component sizes. No additional clinical information was reviewed. Acetabular and femoral component sizes were assessed by an orthopedic surgeon and two radiologists. Mean and estimated component size was compared with component size as documented in operative reports. The mean estimated acetabular component size was 53 mm (range 48-60 mm), 1 mm larger than the mean implanted size of 52 mm (range 48-62 mm). Thirty-one of 36 acetabular component sizes (86%) were accurate within one size. The mean calculated femoral component size was 4 (range 2-7), 1 size smaller than the actual mean component size of 5 (range 2-9). Twenty-six of 36 femoral component sizes (72%) were accurate within one size, and accurate within two sizes in all but four cases (94%). EndoMap Software predicted femoral component size well, with 72% within one component size of that used, and 94% within two sizes. Acetabular component size was predicted slightly better with 86% within one component size and 94% within two component sizes. (orig.)

Outcomes of multiple wire localization for larger breast cancers: when can mastectomy be avoided?

Science.gov (United States)

Kirstein, Laurie J; Rafferty, Elizabeth; Specht, Michelle C; Moore, Richard H; Taghian, Alphonse G; Hughes, Kevin S; Gadd, Michele A; Smith, Barbara L

2008-09-01

Mastectomy is often recommended when mammography shows a breast cancer with extensive calcifications. We wished to determine whether the use of multiple localizing wires to guide lumpectomy in this setting was associated with increased rates of breast conservation. We also wanted to identify factors that predicted a poor chance of successful lumpectomy, to avoid multiple lumpectomy attempts in a patient who would ultimately require mastectomy. Records of 153 women with breast cancer who underwent lumpectomy for larger lesions that required multiple wire localization and 196 controls who required only single wire localization were reviewed retrospectively. The number of localizing wires, specimen volume, largest specimen dimension, number of surgical procedures, and rates of breast conservation were scored. Seventy-seven percent of patients requiring multiple wire localization had successful breast conservation, compared with 90% of those needing only single wire localization. Only 28% of multiple wire patients required more than 1 excision to achieve clear margins, compared with 36% of single wire patients (p localizing wires for excision. The use of multiple wires can decrease the number of procedures required to obtain clear lumpectomy margins.

A Kirschner wire as a transverse-axis guide to improve acetabular cup positioning.

Science.gov (United States)

Ishidou, Y; Hirotsu, M; Setoguchi, T; Nagano, S; Kakoi, H; Yokouchi, M; Yamamoto, T; Komiya, S

2016-04-01

To compare cup-positioning accuracy in total hip arthroplasty (THA) with or without use of a Kirschner wire as a transverse-axis guide for pelvic alignment. Records of 18 men and 73 women (mean age, 60 years) who underwent primary THA with (n=49) or without (n=42) use of a Kirschner wire as a transverse-axis guide for pelvic alignment were reviewed. A 2.4-mm Kirschner wire as a transversea-xis guide was inserted to the anterior superior iliac spine and was parallel to a line linking the left and right anterior superior iliac spine. The safe zone for cup positioning was defined as 30º to 50° abduction and 10º to 30º anteversion. Of the 5 operative surgeons, 2 were classified as experienced (total surgical volume >300) and 3 as inexperienced (total surgical volume of cup in the safe zone was compared in patients with or without use of the transverse-axis guide and in experienced and inexperienced surgeons. For inexperienced surgeons, the use of the transverse-axis guide significantly improved the proportion of patients with the cup in the safe zone from 90% to 100% for abduction, from 50% to 82.4% for anteversion, and from 40% to 82.4% for both. Patients with the cup inside or outside the safe zone were comparable in terms of body height, weight, BMI, subcutaneous fat thickness, incision length, and acetabular cup size. The use of the transverse-axis guide improved the accuracy of cup positioning by inexperienced surgeons.

HIPAA is larger and more complex than Y2K.

Science.gov (United States)

Tempesco, J W

2000-07-01

The Health Insurance Portability and Accountability Act of 1996 (HIPAA) is a larger and more complex problem than Y2K ever was. According to the author, the costs associated with a project of such unending scope and in support of intrusion into both information and operational systems of every health care transaction will be incalculable. Some estimate that the administrative simplification policies implemented through HIPAA will save billions of dollars annually, but it remains to be seen whether the savings will outweigh implementation and ongoing expenses associated with systemwide application of the regulations. This article addresses the rules established for electronic data interchange, data set standards for diagnostic and procedure codes, unique identifiers, coordination of benefits, privacy of individual health care information, electronic signatures, and security requirements.

Segmental acetabular rim defects, bone loss, oversizing, and press fit cup in total hip arthroplasty evaluated with a probabilistic finite element analysis.

Science.gov (United States)

Amirouche, Farid; Solitro, Giovanni F; Walia, Amit; Gonzalez, Mark; Bobko, Aimee

2017-08-01

Management of segmental rim defects and bone mineral density (BMD) loss in the elderly prior to total hip replacement is unclear within classification systems for acetabular bone loss. In this study, our objectives were (1) to understand how a reduction in BMD in the elderly affects the oversizing of a press-fit cup for primary fixation and (2) to evaluate whether the location of the segmental defect affected cup fixation. A finite element (FE) model was used to simulate and evaluate cup insertion and fixation in the context of segmental rim defects. We focused on the distribution of patients over age 70 and used BMD (estimated from CT) as a proxy for aging's implications on THR and used probabilistic FE analysis to understand how BMD loss affects oversizing of a press-fit cup. A cup oversized by 1.10 ± 0.28 mm provides sufficient fixation and lower stresses at the cup-bone interface for elderly patients. Defects in the anterior column and posterior column both required the same mean insertion force for cup seating of 84% (taken as an average of 2 anterior column and 2 posterior column defects) compared to the control configuration, which was 5% greater than the insertion force for a superior rim defect and 12% greater than the insertion force for an inferior rim defect. A defect along the superior or inferior rim had a minimal effect on cup fixation, while a defect in the columns created cup instability and increased stress at the defect location.

Why have microsaccades become larger?

DEFF Research Database (Denmark)

Hansen, Dan Witzner; Nyström, Marcus; Andersson, Richard

2014-01-01

-trackers compared to the systems used in the classical studies, in combination with the lack of a systematic algorithmic treatment of the overshoot. We hope that awareness of these discrepancies in microsaccade dynamics across eye structures will lead to more generally accepted definitions of microsaccades....... experts. The main reason was that the overshoots were not systematically detected by the algorithm and therefore not accurately accounted for. We conclude that one reason to why the reported size of microsaccades has increased is due to the larger overshoots produced by the modern pupil-based eye...

Ex Vivo Evaluation of Cementless Acetabular Cup Stability Using Impact Analyses with a Hammer Instrumented with Strain Sensors.

Science.gov (United States)

Tijou, Antoine; Rosi, Giuseppe; Hernigou, Philippe; Flouzat-Lachaniette, Charles-Henri; Haïat, Guillaume

2017-12-27

The acetabular cup (AC) implant stability is determinant for the success of cementless hip arthroplasty. A method based on the analysis of the impact force applied during the press-fit insertion of the AC implant using a hammer instrumented with a force sensor was developed to assess the AC implant stability. The aim of the present study was to investigate the performance of a method using a hammer equipped with strain sensors to retrieve the AC implant stability. Different AC implants were inserted in five bovine samples with different stability conditions leading to 57 configurations. The AC implant was impacted 16 times by the two hammers consecutively. For each impact; an indicator I S (respectively I F ) determined by analyzing the time variation of the signal corresponding to the averaged strain (respectively force) obtained with the stress (respectively strain) hammer was calculated. The pull-out force F was measured for each configuration. F was significantly correlated with I S (R² = 0.79) and I F (R² = 0.80). The present method has the advantage of not modifying the shape of the hammer that can be sterilized easily. This study opens new paths towards the development of a decision support system to assess the AC implant stability.

Imaging samples larger than the field of view: the SLS experience

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Vogiatzis Oikonomidis, Ioannis; Lovric, Goran; Cremona, Tiziana P.; Arcadu, Filippo; Patera, Alessandra; Schittny, Johannes C.; Stampanoni, Marco

2017-06-01

Volumetric datasets with micrometer spatial and sub-second temporal resolutions are nowadays routinely acquired using synchrotron X-ray tomographic microscopy (SRXTM). Although SRXTM technology allows the examination of multiple samples with short scan times, many specimens are larger than the field-of-view (FOV) provided by the detector. The extension of the FOV in the direction perpendicular to the rotation axis remains non-trivial. We present a method that can efficiently increase the FOV merging volumetric datasets obtained by region-of-interest tomographies in different 3D positions of the sample with a minimal amount of artefacts and with the ability to handle large amounts of data. The method has been successfully applied for the three-dimensional imaging of a small number of mouse lung acini of intact animals, where pixel sizes down to the micrometer range and short exposure times are required.

Is Parental Involvement Lower at Larger Schools?

Science.gov (United States)

Walsh, Patrick

2010-01-01

Parents who volunteer, or who lobby for improvements in school quality, are generally seen as providing a school-wide public good. If so, straightforward public-good theory predicts that free-riding will reduce average involvement at larger schools. This study uses longitudinal data to follow families over time, as their children move from middle…

SME routes for innovation collaboration with larger enterprises

DEFF Research Database (Denmark)

Brink, Tove

2017-01-01

The research in this paper reveals how Small and Medium-sized Enterprises (SMEs) can contribute to industry competiveness through collaboration with larger enterprises. The research is based on a longitudinal qualitative case study starting in 2011 with 10 SME offshore wind farm suppliers...... and follow-up interviews in 2013. The research continued with a second approach in 2014 within operation and maintenance (O&M) through focus group interviews and subsequent individual interviews with 20 enterprises and a seminar in May 2015. The findings reveal opportunities and challenges for SMEs according...... to three different routes for cooperation and collaboration with larger enterprises: demand-driven cooperation, supplier-driven cooperation and partnerdriven collaboration. The SME contribution to innovation and competiveness is different within the three routes and ranges from providing specific knowledge...

Collecting the neclected kingdom: Guidelines for the field mycologist with emphasis on the larger fungi

DEFF Research Database (Denmark)

Buyck, B.; Læssøe, Thomas; Meyer, Marianne

2010-01-01

Guidelines are provided for collecting a group of organisms that has often been overlooked in earlier inventories: the kingdom Fungi and other groups that are traditionally collected by mycologists such as slime molds. After a short introduction on fungi and the feasibility of an ‘all fungal taxa......’ inventory, the authors divide the fungi in six ‘practical’ groups that require specific approaches: slime molds, lichens, parasitic fungi of plants and animals, larger mushrooms, microscopic fungi. Various topics are discussed in relation to three chronological stages (before, during and after...

Instability after total hip arthroplasty

Science.gov (United States)

Werner, Brian C; Brown, Thomas E

2012-01-01

Instability following total hip arthroplasty (THA) is an unfortunately frequent and serious problem that requires thorough evaluation and preoperative planning before surgical intervention. Prevention through optimal index surgery is of great importance, as the management of an unstable THA is challenging even for an experienced joints surgeon. However, even after well-planned surgery, a significant incidence of recurrent instability still exists. Non-operative management is often successful if the components are well-fixed and correctly positioned in the absence of neurocognitive disorders. If conservative management fails, surgical options include revision of malpositioned components; exchange of modular components such as the femoral head and acetabular liner; bipolar arthroplasty; tripolar arthroplasty; use of a larger femoral head; use of a constrained liner; soft tissue reinforcement and advancement of the greater trochanter. PMID:22919568

Human resource management and career planning in a larger library

Directory of Open Access Journals (Sweden)

Jelka Gazvoda

1997-01-01

Full Text Available Human resource management is presented as a managerial function which is used to develop potential abilities of the employees to achieve organizational goals.Different perception of the employees is essential - people working in the organization are treated as capital and not as an expenditure. In human resource management the most important view of the employees is their potential growth and professional development, training for acquiring new responsibilities and encouragement for innovation. Library management is becoming more and more complex as the result of introducing new technologies. For this reason libraries need well trained people with potentials to modernize library performance and to overcome the conflict between the traditional organizational culture and the requirements of the modem technologically developed environment. The author presents different techniques of active human resource management, which can be used in larger libraries where an appropriate number of employees exists to realize different programmes with. These are programmes for education, staffing,career planning, stimmulation and reward systems, job redefinition and enrichment,and other forms of internal segmentation.

Hip arthroscopy in patients with recurrent pain following Bernese periacetabular osteotomy for acetabular dysplasia: operative findings and clinical outcomes

Science.gov (United States)

Cvetanovich, Gregory L.; Heyworth, Benton E.; Murray, Kerri; Yen, Yi-Meng; Kocher, Mininder S.; Millis, Michael B.

2015-01-01

To report the operative findings and outcomes of hip arthroscopy for recurrent pain following periacetabular osteotomy (PAO) for acetabular dysplasia. A departmental database was used to identify patients who underwent hip arthroscopy following PAO between 2000 and 2009. Demographic data, arthroscopic findings, functional outcome scores and patient satisfaction were analysed. Of 556 PAO patients, 17 hips in 16 patients (3.1%) underwent post-PAO hip arthroscopy. Mean age at PAO was 23.8 years, and mean age at arthroscopy was 27.0 years. Common hip arthroscopy findings included labral tears (13 hips, 81.3%), significant (≥grade 2) chondral changes (12 hips, 75%), cam impingement (7 hips, 43.8%) and pincer impingement (6 hips, 37.5%). At mean follow-up 2.8 years after arthroscopy, additional procedures had been performed in six hips (37.5%), including total hip arthroplasty in one hip. Post-PAO arthroscopy questionnaire revealed 85.7% of patients with improved hip pain, 57.1% improved hip stiffness and 57.1% improved hip function. There was no significant difference in functional outcome measures. Common post-PAO hip arthroscopy findings include labral tears, chondral changes and femoroacetabular impingement. Many patients reported subjective hip improvement from post-PAO arthroscopy, but hip outcome scores were unchanged and one-third of patients had further surgery. PMID:27011852

Palliative surgery for acetabular metastasis with pathological central dislocation of the hip joint after radiation therapy. A case report

International Nuclear Information System (INIS)

Hoshi, Manabu; Takada, Jun; Oebisu, Naoto; Nakamura, Hiroaki; Taguchi, Susumu; Takami, Masatsugu

2012-01-01

Orthopedic surgery for bone metastases is mainly a palliative treatment. Pathological central dislocation of the hip joint secondary to osteonecrosis of acetabular metastasis after radiation therapy brings severe suffering to cancer patients. We performed minimally invasive palliative surgery for an elderly woman, and excellent pain relief was achieved. An 80-year-old female suffering from right hip pain was referred to our hospital. She had undergone surgery for lung cancer 5 years previously and her right acetabulum was subsequently affected by metastasis. With the aim of controlling the metastasis, radiation therapy was performed. Two years later, pathological central dislocation of the hip joint occurred with sudden onset of severe pain, and she was unable to maintain a sitting position and became bedridden. After she was referred to our hospital, we created an intentional pseudarthrosis in the femoral neck for palliation. After the surgery, excellent pain relief and remarkably improved mobility were achieved during her limited remaining lifetime. In this report, we introduce a novel method of producing a pseudarthrosis in the femoral neck for pathological dislocation. This procedure is a minimally invasive treatment and an alternative option for palliative surgery for pathological dislocation of the hip joint due to osteonecrosis after radiation therapy. (author)

Source-to-detector distance and beam center do not affect radiographic measurements of acetabular morphology

International Nuclear Information System (INIS)

Goldman, Ashton H.; Hoover, Kevin B.

2017-01-01

Multiple radiographic acquisition techniques have been evaluated for their effect on measurements of acetabular morphology. This cadaveric study examined the effect of two acquisition parameters not previously evaluated: beam center position and source-to-detector distance. This study also evaluated the effect of reader differences on measurements. Following calibration of measurements between two readers using five clinical radiographs (training), radiographs were obtained from two cadavers using four different source-to-detector distances and three different radiographic centers for a total of 12 radiographic techniques (experimental). Two physician readers acquired four types of measurements from each cadaver radiograph: lateral center edge angle, peak-to-edge distance, Sharp's angle, and the Tonnis angle. All measurements were evaluated for intra-class correlation coefficient (ICC), kappa statistics for hip dysplasia, and factors that resulted in measurement differences using a mixed statistical model. After training of the two physician readers, there was strong agreement in their hip morphology measurements (ICC 0.84-0.93), agreement in the presence of hip dysplasia (κ = 0.58-1.0), and no measurement difference between physician readers (p = 0.12-1.0). Experimental cadaver measurements showed moderate-to-strong agreement of the readers (ICC 0.74-0.93) and complete agreement on dysplasia (κ = 1). After accounting for reader and radiographic technique, there was no difference in hip morphology measurements (p = 0.83-0.99). In this cadaveric study, measurements of hip morphology were not affected by varying source-to-detector distance or beam center. We conclude that these acquisition parameters are not likely to affect the diagnosis of hip dysplasia in a clinical setting. (orig.)

Source-to-detector distance and beam center do not affect radiographic measurements of acetabular morphology

Energy Technology Data Exchange (ETDEWEB)

Goldman, Ashton H. [Department of Orthopaedic Surgery, Virginia Commonwealth University, Richmond, VA (United States); Hoover, Kevin B. [Virginia Commonwealth University, Department of Radiology, 1250 E Marshall St. 3rd Floor, PO Box 980615, Richmond, VA (United States)

2017-04-15

Multiple radiographic acquisition techniques have been evaluated for their effect on measurements of acetabular morphology. This cadaveric study examined the effect of two acquisition parameters not previously evaluated: beam center position and source-to-detector distance. This study also evaluated the effect of reader differences on measurements. Following calibration of measurements between two readers using five clinical radiographs (training), radiographs were obtained from two cadavers using four different source-to-detector distances and three different radiographic centers for a total of 12 radiographic techniques (experimental). Two physician readers acquired four types of measurements from each cadaver radiograph: lateral center edge angle, peak-to-edge distance, Sharp's angle, and the Tonnis angle. All measurements were evaluated for intra-class correlation coefficient (ICC), kappa statistics for hip dysplasia, and factors that resulted in measurement differences using a mixed statistical model. After training of the two physician readers, there was strong agreement in their hip morphology measurements (ICC 0.84-0.93), agreement in the presence of hip dysplasia (κ = 0.58-1.0), and no measurement difference between physician readers (p = 0.12-1.0). Experimental cadaver measurements showed moderate-to-strong agreement of the readers (ICC 0.74-0.93) and complete agreement on dysplasia (κ = 1). After accounting for reader and radiographic technique, there was no difference in hip morphology measurements (p = 0.83-0.99). In this cadaveric study, measurements of hip morphology were not affected by varying source-to-detector distance or beam center. We conclude that these acquisition parameters are not likely to affect the diagnosis of hip dysplasia in a clinical setting. (orig.)

A New Automated Way to Measure Polyethylene Wear in THA Using a High Resolution CT Scanner: Method and Analysis

Directory of Open Access Journals (Sweden)

Gerald Q. Maguire Jr.

2014-01-01

Full Text Available As the most advantageous total hip arthroplasty (THA operation is the first, timely replacement of only the liner is socially and economically important because the utilization of THA is increasing as younger and more active patients are receiving implants and they are living longer. Automatic algorithms were developed to infer liner wear by estimating the separation between the acetabular cup and femoral component head given a computed tomography (CT volume. Two series of CT volumes of a hip phantom were acquired with the femoral component head placed at 14 different positions relative to the acetabular cup. The mean and standard deviation (SD of the diameter of the acetabular cup and femoral component head, in addition to the range of error in the expected wear values and the repeatability of all the measurements, were calculated. The algorithms resulted in a mean (±SD for the diameter of the acetabular cup of 54.21 (±0.011 mm and for the femoral component head of 22.09 (±0.02 mm. The wear error was ±0.1 mm and the repeatability was 0.077 mm. This approach is applicable clinically as it utilizes readily available computed tomography imaging systems and requires only five minutes of human interaction.

When the proton becomes larger

CERN Multimedia

CERN Bulletin

2011-01-01

The TOTEM experiment at the LHC has just confirmed that, at high energy, protons behave as if they were becoming larger. In more technical terms, their total cross-section – a parameter linked to the proton-proton interaction probability – increases with energy. This phenomenon, expected from previous measurements performed at much lower energy, has now been confirmed for the first time at the LHC’s unprecedented energy.   One arm of a TOTEM T2 detector during its installation at interaction point 5. A composite particle like the proton is a complex system that in no way resembles a static Lego construction: sub-components move inside and interactions keep the whole thing together, but in a very dynamic way. This partly explains why even the very common proton can still be hiding secrets about its nature, decades after its discovery. One way of studying the inner properties of protons is to observe how they interact with each other, which, in technical terms, i...

Larger men have larger prostates: Detection bias in epidemiologic studies of obesity and prostate cancer risk.

Science.gov (United States)

Rundle, Andrew; Wang, Yun; Sadasivan, Sudha; Chitale, Dhananjay A; Gupta, Nilesh S; Tang, Deliang; Rybicki, Benjamin A

2017-06-01

Obesity is associated with risk of aggressive prostate cancer (PCa), but not with over-all PCa risk. However, obese men have larger prostates which may lower biopsy accuracy and cause a systematic bias toward the null in epidemiologic studies of over-all risk. Within a cohort of 6692 men followed-up after a biopsy or transurethral resection of the prostate (TURP) with benign findings, a nested case-control study was conducted of 495 prostate cancer cases and controls matched on age, race, follow-up duration, biopsy versus TURP, and procedure date. Data on body mass index and prostate volume at the time of the initial procedure were abstracted from medical records. Prior to consideration of differences in prostate volume, overweight (OR = 1.41; 95%CI 1.01, 1.97), and obese status (OR = 1.59; 95%CI 1.09, 2.33) at the time of the original benign biopsy or TURP were associated with PCa incidence during follow-up. Prostate volume did not significantly moderate the association between body-size and PCa, however it did act as an inverse confounder; adjustment for prostate volume increased the effect size for overweight by 22% (adjusted OR = 1.52; 95%CI 1.08, 2.14) and for obese status by 23% (adjusted OR = 1.77; 95%CI 1.20, 2.62). Larger prostate volume at the time of the original benign biopsy or TURP was inversely associated with PCa incidence during follow-up (OR = 0.92 per 10 cc difference in volume; 95%CI 0.88, 0.97). In analyses that stratified case-control pairs by tumor aggressiveness of the case, prostate volume acted as an inverse confounder in analyses of non-aggressive PCa but not in analyses of aggressive PCa. In studies of obesity and PCa, differences in prostate volume cause a bias toward the null, particularly in analyses of non-aggressive PCa. A pervasive underestimation of the association between obesity and overall PCa risk may exist in the literature. © 2017 Wiley Periodicals, Inc.

Migration pattern of cementless press fit cups in the presence of stabilizing screws in total hip arthroplasty

Directory of Open Access Journals (Sweden)

Zilkens C

2011-03-01

Full Text Available Abstract The aim of this study was to evaluate the initial acetabular implant stability and late acetabular implant migration in press fit cups combined with screw fixation of the acetabular component in order to answer the question whether screws are necessary for the fixation of the acetabular component in cementless primary total hip arthroplasty. One hundred and seven hips were available for follow-up after primary THA using a cementless, porous-coated acetabular component. A total of 631 standardized radiographs were analyzed digitally by the "single-film-x-ray-analysis" method (EBRA. One hundred 'and one (94.4% acetabular components did not show significant migration of more than 1 mm. Six (5.6% implants showed migration of more than 1 mm. Statistical analysis did not reveal preoperative patterns that would identify predictors for future migration. Our findings suggest that the use of screw fixation for cementless porous- coated acetabular components for primary THA does not prevent cup migration.

Electrodialytic removal of cadmium from biomass combustion fly ash in larger scale

DEFF Research Database (Denmark)

Pedersen, Anne Juul; Ottosen, Lisbeth M.; Simonsen, Peter

2005-01-01

Due to a high concentration of the toxic heavy metal cadmium (Cd), biomass combustion fly ash often fails to meet the Danish legislative requirements for recycling on agricultural fields. It has previously been shown that it is possible to reduce the concentration of Cd in different bio ashes...... significantly by using electrodialytic remediation, an electrochemically assisted extraction method. In this work the potential of the method was demonstrated in larger scale. Three different experimental set-ups were used, ranging from bench-scale (25 L ash suspension) to pilot scale (0.3 - 3 m3......). The experimental ash was a straw combustion fly ash suspended in water. Within 4 days of remediation, Cd concentrations below the limiting concentration of 5.0 mg Cd/kg DM for straw ash were reached. On the basis of these results, the energy costs for remediation of ash in industrial scale have been estimated...

Design of reactor internals in larger high-temperature reactors with spherical fuel elements

International Nuclear Information System (INIS)

Elter, C.

1981-01-01

In his paper, the author analyzes and summarizes the present state of the art with emphasis on the prototype reactor THTR 300 MWe, because in addition to spherical fuel elements, this type includes other features of future HTR design such as the same flow direction of cooland gas through the core. The paper on hand also elaborates design guidelines for reactor internals applicable with large HTR's of up to 1200 MWe. Proved designs will be altered so as to meet the special requirements of larger cores with spherical elements to be reloaded according to the OTTO principle. This paper is furthermore designed as a starting point for selective and swift development of reactor internals for large HTR's to be refuelled according to the OTTO principle. (orig./GL) [de

Listing of nuclear power plant larger than 100 MWe

International Nuclear Information System (INIS)

McHugh, B.

1976-03-01

This report contains a list of all nuclear power plants larger than 100 MWe, printed out from the Argus Data Bank at Chalmers University of Technology in Sweden. The plants are listed by NSSS supply. (M.S.)

Why borrowers pay premiums to larger lenders: Empirical evidence from sovereign syndicated loans

OpenAIRE

Hallak, Issam

2002-01-01

All other terms being equal (e.g. seniority), syndicated loan contracts provide larger lending compensations (in percentage points) to institutions funding larger amounts. This paper explores empirically the motivation for such a price design on a sample of sovereign syndicated loans in the period 1990-1997. I find strong evidence that a larger premium is associated with higher renegotiation probability and information asymmetries. It hardly has any impact on the number of lenders though. Thi...

Annual spatiotemporal migration schedules in three larger insectivorous birds

DEFF Research Database (Denmark)

Jacobsen, Lars Bo; Jensen, Niels Odder; Willemoes, Mikkel

2017-01-01

Background: Knowledge of spatiotemporal migration patterns is important for our understanding of migration ecology and ultimately conservation of migratory species. We studied the annual migration schedules of European nightjar, a large nocturnal insectivore and compared it with two other larger ...

The Larger Linear N-Heteroacenes

KAUST Repository

Bunz, Uwe H. F.

2015-01-01

© 2015 American Chemical Society. ConspectusThe close structural and chemical relationship of N-heteroacenes to pentacene suggests their broad applicability in organic electronic devices, such as thin-film transistors. The superb materials science properties of azaacenes result from their improved resistance toward oxidation and their potential for electron transport, both of which have been demonstrated recently. The introduction of nitrogen atoms into the aromatic perimeter of acenes stabilizes their frontier molecular orbitals and increases their electron affinity. The HOMO-LUMO gaps in azaacenes in which the nitrogen atoms are symmetrically placed are similar to those of the acenes. The judiciously placed nitrogen atoms induce an "umpolung" of the electronic behavior of these pentacene-like molecules, i.e., instead of hole mobility in thin-film transistors, azaacenes are electron-transporting materials. The fundamental synthetic approaches toward larger azaacenes are described and discussed. Several synthetic methodologies have been exploited, and some have been newly developed to assemble substituted azaacenes. The oldest methods are condensation-based. Aromatic o-diamines are coupled with o-dihydroxyarenes in the melt without solvent. This method works well for unsubstituted azaacenes only. The attachment of substituents to the starting materials renders these "fire and sword" methods less useful. The starting materials decompose under these conditions. The direct condensation of substituted o-diamines with o-quinones proceeds well in some cases. Fluorinated benzene rings next to a pyrazine unit are introduced by nucleophilic aromatic substitution employing hexafluorobenzene. However, with these well-established synthetic methodologies, a number of azaacene topologies cannot be synthesized. The Pd-catalyzed coupling of aromatic halides and aromatic diamines has therefore emerged as versatile tool for azaacene synthesis. Now substituted diaza- and

The Larger Linear N-Heteroacenes

KAUST Repository

Bunz, Uwe H. F.

2015-06-16

© 2015 American Chemical Society. ConspectusThe close structural and chemical relationship of N-heteroacenes to pentacene suggests their broad applicability in organic electronic devices, such as thin-film transistors. The superb materials science properties of azaacenes result from their improved resistance toward oxidation and their potential for electron transport, both of which have been demonstrated recently. The introduction of nitrogen atoms into the aromatic perimeter of acenes stabilizes their frontier molecular orbitals and increases their electron affinity. The HOMO-LUMO gaps in azaacenes in which the nitrogen atoms are symmetrically placed are similar to those of the acenes. The judiciously placed nitrogen atoms induce an "umpolung" of the electronic behavior of these pentacene-like molecules, i.e., instead of hole mobility in thin-film transistors, azaacenes are electron-transporting materials. The fundamental synthetic approaches toward larger azaacenes are described and discussed. Several synthetic methodologies have been exploited, and some have been newly developed to assemble substituted azaacenes. The oldest methods are condensation-based. Aromatic o-diamines are coupled with o-dihydroxyarenes in the melt without solvent. This method works well for unsubstituted azaacenes only. The attachment of substituents to the starting materials renders these "fire and sword" methods less useful. The starting materials decompose under these conditions. The direct condensation of substituted o-diamines with o-quinones proceeds well in some cases. Fluorinated benzene rings next to a pyrazine unit are introduced by nucleophilic aromatic substitution employing hexafluorobenzene. However, with these well-established synthetic methodologies, a number of azaacene topologies cannot be synthesized. The Pd-catalyzed coupling of aromatic halides and aromatic diamines has therefore emerged as versatile tool for azaacene synthesis. Now substituted diaza- and

Direct and indirect costs of surgically treated pelvic fractures.

Science.gov (United States)

Aprato, Alessandro; Joeris, Alexander; Tosto, Ferdinando; Kalampoki, Vasiliki; Stucchi, Alessandro; Massè, Alessandro

2016-03-01

Pelvic fractures requiring surgical fixation are rare injuries but present a great societal impact in terms of disability, as well as economic resources. In the literature, there is no description of these costs. Main aim of this study is to describe the direct and indirect costs of these fractures. Secondary aims were to test if the type of fracture (pelvic ring injury or acetabular fracture) influences these costs (hospitalization, consultation, medication, physiotherapy sessions, job absenteeism). We performed a retrospective study on patients with surgically treated acetabular fractures or pelvic ring injuries. Medical records were reviewed in terms of demographic data, follow-up, diagnosis (according to Letournel and Tile classifications for acetabular and pelvic fractures, respectively) and type of surgical treatment. Patients were interviewed about hospitalization length, consultations after discharge, medications, physiotherapy sessions and absenteeism. The study comprised 203 patients, with a mean age of 49.1 ± 15.6 years, who had undergone surgery for an acetabular fracture or pelvic ring injury. The median treatment costs were 29.425 Euros per patient. Sixty percent of the total costs were attributed to health-related work absence. Median costs (in Euros) were 2.767 for hospitalization from trauma to definitive surgery, 4.530 for surgery, 3.018 for hospitalization in the surgical unit, 1.693 for hospitalization in the rehabilitation unit, 1.920 for physiotherapy after discharge and 402 for consultations after discharge. Total costs for treating pelvic ring injuries were higher than for acetabular fractures, mainly due to the significant higher costs of pelvic injuries regarding hospitalization from trauma to definitive surgery (p fractures are associated with both high direct costs and substantial productivity loss.

Collision cascades and sputtering induced by larger cluster ions

International Nuclear Information System (INIS)

Sigmund, P.

1988-01-01

Recent experimental work on larger cluster impact on solid surfaces suggests large deviations from the standard case of additive sputter yields both in the nuclear and electronic stopping regime. The paper concentrates on elastic collision cascades. In addition to very pronounced spike effects, two phenomena are pointed out that are specific to cluster bombardment. Multiple hits of cluster atoms on one and the same target atom may result in recoil atoms that move faster than the maximum recoil speed for monomer bombardment at the same projectile speed. This effect is important when the atomic mass of a beam atom is less than that of a target atom, M 1 2 . In the opposite case, M 1 >> M 2 , collisions between beam particles may accelerate some beam particles and slow down others. Some consequences are mentioned. Remarks on the nuclear stopping power of larger clusters and on electronic sputtering by cluster bombardment conclude the paper. 38 refs., 2 figs

Computed tomography measurements of the acetabulum in adult dysplastic hips: Which level is appropriate

Energy Technology Data Exchange (ETDEWEB)

Anda, S.; Kvistad, K.A. (Dept. of Radiology, Trondheim Univ. (Norway)); Terjesen, T. (Dept. of Orthopedic Surgery, Trondheim Univ. (Norway))

1991-05-01

A study has been performed to evaluate whether one or several levels are needed with comuted tomography (CT) study to provide sufficient information regarding anteversion and acetabular support to the femoral head. A total of 23 hips in 14 adults with uni- or bilateral congenital hip dysplasia (center-edge angle less than 20deg) were assessed by obtaining 5-mm contiguous CT slices and performing acetabular measurements at four levels. Both anterior and posterior acetabular supports as quantified by the anterior and posterior acetabular sector angles were significantly lower than normal at all levels. The sector angles increased in the proximal cuts, whereas the acetabular anteversin increased caudally. Because no important additional information was gained by measuring at different levels, we conclude that CT study at one level is sufficient for acetabular measurements and suggest that the slice through the center of the femoral head is the most appropriate one. (orig.).

Dispersal, phenology and predicted abundance of the larger grain ...

African Journals Online (AJOL)

The phenology and dispersal of the larger grain borer (LGB) in Africa is described, and comparisons are made between prediction of LGB numbers from laboratory studies and predictions from multiple linear models derived from trapping data in the field. The models were developed in Mexico and Kenya, using ...

Prevalence of the acetabular sublabral sulcus at MR arthrography in patients under 17 years of age: does it exist?

Energy Technology Data Exchange (ETDEWEB)

Magerkurth, Olaf [University of Michigan, Department of Radiology, Ann Arbor, MI (United States); Hospital Baden, Department of Radiology, Baden (Switzerland); Jacobson, Jon A.; Morag, Yoav; Fessell, David [University of Michigan, Department of Radiology, Ann Arbor, MI (United States); Bedi, Asheesh; Sekiya, Jon K. [University of Michigan, Department of Orthopedic Surgery, Ann Arbor, MI (United States)

2015-04-18

To retrospectively determine characteristics of contrast-filled acetabular labral clefts in patients under the age of 17 years at MR arthrography (Mra) correlated with arthroscopy, which may impact the thinking regarding the existence of a sublabral sulcus. After IRB approval, 41 patients under the age of 17 who had MRa were identified. The following observations of contrast-filled clefts were assessed: (1) presence/absence, (2) location, (3) depth, (4) abnormal signal within the labrum and (5) shape (linear, gaping, complex). Fisher's exact and the Wilcoxon matched-pairs signed-rank test were performed. Interreader agreement was calculated with Cohen's k. Reader 1 found clefts in 41 %. Depth was less than half in 6 %, more than half in 65 % and full thickness in 29 %. Shape was linear in 53 %, gaping in 18 % and complex in 29 %. Signal changes occurred in 88 %. Reader 2 found clefts in 29 %. Depth was less than half in 17 %, more than half in 58 % and full thickness in 25 %. Shape was linear in 50 %, gaping in 42 % and complex in 17 %. Signal changes occurred in 50 %. None of the clefts fulfilled the criteria for a sublabral sulcus at MRa and arthroscopy. None of the clefts found in our subjects under the age of 17 years met the MRa and arthroscopy criteria for a sublabral sulcus, which supports the theory that such clefts represent labral tears. (orig.)

Development of an acoustic measurement protocol to monitor acetabular implant fixation in cementless total hip Arthroplasty: A preliminary study.

Science.gov (United States)

Goossens, Quentin; Leuridan, Steven; Henyš, Petr; Roosen, Jorg; Pastrav, Leonard; Mulier, Michiel; Desmet, Wim; Denis, Kathleen; Vander Sloten, Jos

2017-11-01

In cementless total hip arthroplasty (THA), the initial stability is obtained by press-fitting the implant in the bone to allow osseointegration for a long term secondary stability. However, finding the insertion endpoint that corresponds to a proper initial stability is currently based on the tactile and auditory experiences of the orthopedic surgeon, which can be challenging. This study presents a novel real-time method based on acoustic signals to monitor the acetabular implant fixation in cementless total hip arthroplasty. Twelve acoustic in vitro experiments were performed on three types of bone models; a simple bone block model, an artificial pelvic model and a cadaveric model. A custom made beam was screwed onto the implant which functioned as a sound enhancer and insertor. At each insertion step an acoustic measurement was performed. A significant acoustic resonance frequency shift was observed during the insertion process for the different bone models; 250 Hz (35%, second bending mode) to 180 Hz (13%, fourth bending mode) for the artificial bone block models and 120 Hz (11%, eighth bending mode) for the artificial pelvis model. No significant frequency shift was observed during the cadaveric experiment due to a lack of implant fixation in this model. This novel diagnostic method shows the potential of using acoustic signals to monitor the implant seating during insertion. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Hip Joint Osteochondroma: Systematic Review of the Literature and Report of Three Further Cases

Directory of Open Access Journals (Sweden)

Asim M. Makhdom

2014-01-01

Full Text Available The aim of this study is to systematically review the literature with regards to surgical treatment of patients with hip joint osteochondromas, and to report our surgical management of three paediatric patients who had femoral neck or acetabular osteochondromas in association with acetabular dysplasia. We performed a systematic review using PubMed and Embase databases for all studies that reported surgical treatments for patients with peritrochanteric or acetabular osteochondroma with or without acetabular dysplasia. We also retrospectively reviewed three patients who were diagnosed with a hip osteochondroma in association with actetabular dysplasia. These patients were known to have hereditary multiple exostoses (HME. The systematic review revealed 21 studies that met our inclusion criteria. All studies were case reports and retrospective in nature and failed to conclude a uniform treatment plan. The three reported cases illustrate successful excision of hip osteochondromas and treatment of acetabular dysplasia. Early excision of hip osteochondromas might prevent acetabular dysplasia in HME patients. Routine radiographic pelvic survey at the time of diagnosis of HME is recommended for early detection of hip osteochondromas and acetabular dysplasia in these children.

29 CFR 779.232 - Franchise or other arrangements which create a larger enterprise.

Science.gov (United States)

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false Franchise or other arrangements which create a larger... Apply; Enterprise Coverage Leased Departments, Franchise and Other Business Arrangements § 779.232 Franchise or other arrangements which create a larger enterprise. (a) In other instances, franchise...

[Research progress of larger flexion gap than extension gap in total knee arthroplasty].

Science.gov (United States)

Zhang, Weisong; Hao, Dingjun

2017-05-01

To summarize the progress of larger flexion gap than extension gap in total knee arthro-plasty (TKA). The domestic and foreign related literature about larger flexion gap than extension gap in TKA, and its impact factors, biomechanical and kinematic features, and clinical results were summarized. During TKA, to adjust the relations of flexion gap and extension gap is one of the key factors of successful operation. The biomechanical, kinematic, and clinical researches show that properly larger flexion gap than extension gap can improve both the postoperative knee range of motion and the satisfaction of patients, but does not affect the stability of the knee joint. However, there are also contrary findings. So adjustment of flexion gap and extension gap during TKA is still in dispute. Larger flexion gap than extension gap in TKA is a new joint space theory, and long-term clinical efficacy, operation skills, and related complications still need further study.

Listing of nuclear power plant larger than 100 MWe

International Nuclear Information System (INIS)

McHugh, B.

1975-06-01

This report contains a list of all nuclear power plants larger than 100 MWe, printed out from the Argus Data Bank at Chalmers University of Technology in Sweden. The plants are listed alphabetically. The report contains also a plant ranking list, where the plants are listed by the load factor (12 months) (M.S.)

Listing of nuclear power plant larger than 100 MWe

International Nuclear Information System (INIS)

McHugh, B.

1975-12-01

This report contains a list of all nuclear power plants larger than 100 MWe, printed out from the Argus Data Bank at Chalmers University of Technology in Sweden. The plants are listed by country. The report contains also a plant ranking list, where the plants are listed by the load factor (12 months). (M.S.)

48 CFR 8.1102 - Presolicitation requirements.

Science.gov (United States)

2010-10-01

... ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES Leasing of Motor Vehicles 8.1102 Presolicitation requirements. (a) Except as specified in 8.1102(b), before preparing solicitations for leasing of... automobiles (sedans and station wagons) larger than Type IA, IB, or II (small, subcompact, or compact) are...

Larger ATV engine size correlates with an increased rate of traumatic brain injury.

Science.gov (United States)

Butts, C Caleb; Rostas, Jack W; Lee, Y L; Gonzalez, Richard P; Brevard, Sidney B; Frotan, M Amin; Ahmed, Naveed; Simmons, Jon D

2015-04-01

Since the introduction of all-terrain vehicles (ATV) to the United States in 1971, injuries and mortalities related to their use have increased significantly. Furthermore, these vehicles have become larger and more powerful. As there are no helmet requirements or limitations on engine-size in the State of Alabama, we hypothesised that larger engine size would correlate with an increased incidence of traumatic brain injury (TBI) in patients following an ATV crash. Patient and ATV data were prospectively collected on all ATV crashes presenting to a level one trauma centre from September 2010 to May 2013. Collected data included: demographics, age of driver, ATV engine size, presence of helmet, injuries, and outcomes. The data were grouped according to the ATV engine size in cubic centimetres (cc). For the purposes of this study, TBI was defined as any type of intracranial haemorrhage on the initial computed tomography scan. There were 61 patients identified during the study period. Two patients (3%) were wearing a helmet at the time of injury. Patients on an ATV with an engine size of 350 cc or greater had higher Injury Severity Scores (13.9 vs. 7.5, p ≤ 0.05) and an increased incidence of TBI (26% vs. 0%, p ≤ 0.05) when compared to patients on ATV's with an engine size less than 350 cc. Patients on an ATV with an engine size of 350 cc or greater were more likely to have a TBI. The use of a helmet was rarely present in this cohort. Legislative efforts to implement rider protection laws for ATVs are warranted. Copyright © 2014 Elsevier Ltd. All rights reserved.

More 'altruistic' punishment in larger societies.

Science.gov (United States)

Marlowe, Frank W; Berbesque, J Colette

2008-03-07

If individuals will cooperate with cooperators, and punish non-cooperators even at a cost to themselves, then this strong reciprocity could minimize the cheating that undermines cooperation. Based upon numerous economic experiments, some have proposed that human cooperation is explained by strong reciprocity and norm enforcement. Second-party punishment is when you punish someone who defected on you; third-party punishment is when you punish someone who defected on someone else. Third-party punishment is an effective way to enforce the norms of strong reciprocity and promote cooperation. Here we present new results that expand on a previous report from a large cross-cultural project. This project has already shown that there is considerable cross-cultural variation in punishment and cooperation. Here we test the hypothesis that population size (and complexity) predicts the level of third-party punishment. Our results show that people in larger, more complex societies engage in significantly more third-party punishment than people in small-scale societies.

Hip morphologic measurements in an Egyptian population.

Science.gov (United States)

Aly, Tarek A

2011-04-11

The study of acetabular morphology has shown that there are geographic differences in the morphology and prevalence of acetabular dysplasia among different ethnic groups. However, few data exist on the shape of the acetabulum in various populations around the world. In this study, we examined samples of pelvic radiographs from Egyptian adults. Acetabular dysplasia in adults is characterized by a shallow and relatively vertical acetabulum.The aim of this study was to examine acetabular morphology to determine the prevalence of hip dysplasia in adult Egyptians. This included 244 adults, 134 men and 110 women between 18 and 60 years, who were used to measure center edge angle, acetabular Sharp angle, acetabular head index on anteroposterior radiographic views of the hip joints, and vertical center anterior margin angle on false profile views. The radiographs were taken of patients with no hip complaints at Tanta University Hospital.The results were statistically studied according to the age, height, and weight of patients. The prevalence of acetabular dysplasia was 2.25% for Egyptian men and 3.6% for women with respect to center edge angles, vertical center anterior margin angle, and acetabular head index.We concluded that gender variations in the morphology of the acetabulum and sex influences geometrical measurements of the acetabulum. Egyptian women were more dysplastic than men using the 4 parameters of hip measurements. There are also racial variations in hip morphology. Copyright 2011, SLACK Incorporated.

Central X-ray beam correction of radiographic acetabular cup measurement after THA: an experimental study.

Science.gov (United States)

Schwarz, T; Weber, M; Wörner, M; Renkawitz, T; Grifka, J; Craiovan, B

2017-05-01

Accurate assessment of cup orientation on postoperative radiographs is essential for evaluating outcome after THA. However, accuracy is impeded by the deviation of the central X-ray beam in relation to the cup and the impossibility of measuring retroversion on standard pelvic radiographs. In an experimental trial, we built an artificial cup holder enabling the setting of different angles of anatomical anteversion and inclination. Twelve different cup orientations were investigated by three examiners. After comparing the two methods for radiographic measurement of the cup position developed by Lewinnek and Widmer, we showed how to differentiate between anteversion and retroversion in each cup position by using a second plane. To show the effect of the central beam offset on the cup, we X-rayed a defined cup position using a multidirectional central beam offset. According to Murray's definition of anteversion and inclination, we created a novel corrective procedure to balance measurement errors caused by deviation of the central beam. Measurement of the 12 different cup positions with the Lewinnek's method yielded a mean deviation of [Formula: see text] (95 % CI 1.3-2.3) from the original cup anteversion. The respective deviation with the Widmer/Liaw's method was [Formula: see text] (95 % CI 2.4-4.0). In each case, retroversion could be differentiated from anteversion with a second radiograph. Because of the multidirectional central beam offset ([Formula: see text] cm) from the acetabular cup in the cup holder ([Formula: see text] anteversion and [Formula: see text] inclination), the mean absolute difference for anteversion was [Formula: see text] (range [Formula: see text] to [Formula: see text] and [Formula: see text] (range [Formula: see text] to [Formula: see text] for inclination. The application of our novel mathematical correction of the central beam offset reduced deviation to a mean difference of [Formula: see text] for anteversion and [Formula: see text

Conventional versus virtual radiographs of the injured pelvis and acetabulum

Energy Technology Data Exchange (ETDEWEB)

Bishop, Julius A.; Rao, Allison J.; Pouliot, Michael A.; Bellino, Michael [Stanford University School of Medicine, Department of Orthopaedic Surgery, Stanford, CA (United States); Beaulieu, Christopher [Stanford University School of Medicine, Department of Radiology, Stanford, CA (United States)

2015-09-15

Evaluation of the fractured pelvis or acetabulum requires both standard radiographic evaluation as well as computed tomography (CT) imaging. The standard anterior-posterior (AP), Judet, and inlet and outlet views can now be simulated using data acquired during CT, decreasing patient discomfort, radiation exposure, and cost to the healthcare system. The purpose of this study is to compare the image quality of conventional radiographic views of the traumatized pelvis to virtual radiographs created from pelvic CT scans. Five patients with acetabular fractures and ten patients with pelvic ring injuries were identified using the orthopedic trauma database at our institution. These fractures were evaluated with both conventional radiographs as well as virtual radiographs generated from a CT scan. A web-based survey was created to query overall image quality and visibility of relevant anatomic structures. This survey was then administered to members of the Orthopaedic Trauma Association (OTA). Ninety-seven surgeons completed the acetabular fracture survey and 87 completed the pelvic fracture survey. Overall image quality was judged to be statistically superior for the virtual as compared to conventional images for acetabular fractures (3.15 vs. 2.98, p = 0.02), as well as pelvic ring injuries (2.21 vs. 1.45, p = 0.0001). Visibility ratings for each anatomic landmark were statistically superior with virtual images as well. Virtual radiographs of pelvic and acetabular fractures offer superior image quality, improved comfort, decreased radiation exposure, and a more cost-effective alternative to conventional radiographs. (orig.)

[Osteosynthesis and cup revision in periprosthetic acetabulum fractures using a Kocher-Langenbeck approach].

Science.gov (United States)

Schwabe, P; Märdian, S; Perka, C; Schaser, K-D

2016-04-01

Reconstruction/stable fixation of the acetabular columns to create an adequate periacetabular requirement for the implantation of a revision cup. Displaced/nondisplaced fractures with involvement of the posterior column. Resulting instability of the cup in an adequate bone stock situation. Periprosthetic acetabulum fractures with inadequate bone stock. Extended periacetabular defects with loss of anchorage options. Isolated periprosthetic fractures of the anterior column. Septic loosening. Dorsal approach. Dislocation of hip. Mechanical testing of inlaying acetabular cup. With unstable cup situation explantation of the cup, fracture fixation of acetabulum with dorsal double plate osteosynthesis along the posterior column. Cup revision. Hip joint reposition. Early mobilization; partial weight bearing for 12 weeks. Thrombosis prophylaxis. Clinical and radiological follow-ups. Periprosthetic acetabular fracture in 17 patients with 9 fractures after primary total hip replacement (THR), 8 after revision THR. Fractures: 12 due to trauma, 5 spontaneously; 7 anterior column fractures, 5 transverse fractures, 4 posterior column fractures, 1 two column fracture after hemiendoprosthesis. 5 type 1 fractures and 12 type 2 fractures. Operatively treated cases (10/17) received 3 reinforcement ring, 2 pedestal cup, 1 standard revision cup, cup-1 cage construct, 1 ventral plate osteosynthesis, 1 dorsal plate osteosynthesis, and 1 dorsal plate osteosynthesis plus cup revision (10-month Harris Hip Score 78 points). Radiological follow-up for 10 patients: consolidation of fractures without dislocation and a fixed acetabular cup. No revision surgeries during follow-up; 2 hip dislocations, 1 transient sciatic nerve palsy.

A contribution to radiotherapy of the larger-celled bronchial carcinoma

International Nuclear Information System (INIS)

Zoubie, I.

1982-01-01

This work consists of a retrospective definition of disease courses of 859 patients with lung tumors and the definition of the survival curves in their dependence on histology, radiation dose and sex. With 721 larger-celled bronchial carcinomas the ratio of men to women was 12:1. The age peak lay between 60 and 70 years. The one/five year survival rate of all included larger-celled bronchial carcinomas (n=701) was, independent from the therapy form, 35.7, resp. 4.78%. The one year/five year survival rates were for the squamous epithelia 31.08/0.58%, for the undifferentiated carcinomas 25.34/3.41%, and for the lung tumors without histology 35.4/5.14%. Lobectomized patients with squamous epithelium carcinoma had in comparison to pneumonectomized patients a clearly higher survival chance. A clearly sex-dependent predisposition for a certain type of carcinoma was not present. (TRV) [de

Accuracy and Precision of Three-Dimensional Low Dose CT Compared to Standard RSA in Acetabular Cups: An Experimental Study.

Science.gov (United States)

Brodén, Cyrus; Olivecrona, Henrik; Maguire, Gerald Q; Noz, Marilyn E; Zeleznik, Michael P; Sköldenberg, Olof

2016-01-01

Background and Purpose. The gold standard for detection of implant wear and migration is currently radiostereometry (RSA). The purpose of this study is to compare a three-dimensional computed tomography technique (3D CT) to standard RSA as an alternative technique for measuring migration of acetabular cups in total hip arthroplasty. Materials and Methods. With tantalum beads, we marked one cemented and one uncemented cup and mounted these on a similarly marked pelvic model. A comparison was made between 3D CT and standard RSA for measuring migration. Twelve repeated stereoradiographs and CT scans with double examinations in each position and gradual migration of the implants were made. Precision and accuracy of the 3D CT were calculated. Results. The accuracy of the 3D CT ranged between 0.07 and 0.32 mm for translations and 0.21 and 0.82° for rotation. The precision ranged between 0.01 and 0.09 mm for translations and 0.06 and 0.29° for rotations, respectively. For standard RSA, the precision ranged between 0.04 and 0.09 mm for translations and 0.08 and 0.32° for rotations, respectively. There was no significant difference in precision between 3D CT and standard RSA. The effective radiation dose of the 3D CT method, comparable to RSA, was estimated to be 0.33 mSv. Interpretation. Low dose 3D CT is a comparable method to standard RSA in an experimental setting.

The hip fluid seal--Part II: The effect of an acetabular labral tear, repair, resection, and reconstruction on hip stability to distraction.

Science.gov (United States)

Nepple, Jeffrey J; Philippon, Marc J; Campbell, Kevin J; Dornan, Grant J; Jansson, Kyle S; LaPrade, Robert F; Wijdicks, Coen A

2014-04-01

The acetabular labrum is theorized to be important to normal hip function by providing stability to distraction forces through the suction effect of the hip fluid seal. The purpose of this study was to determine the relative contributions of the hip capsule and labrum to the distractive stability of the hip, and to characterize hip stability to distraction forces in six labral conditions: intact labrum, labral tear, labral repair (looped vs. through sutures), partial resection, labral reconstruction with iliotibial band, and complete resection. Eight cadaveric hips with a mean age of 47.8 years (SD 4.3, range 41-51 years) were included. For each condition, the hip seal was broken by distracting the hip at a rate of 0.33 mm/s while the required force, energy, and negative intra-articular pressure were measured. For comparisons between labral conditions, measurements were normalized to the intact labral state (percent of intact). The relative contribution of the labrum to distractive stability was greatest at 1 and 2 mm of displacement, where it was significantly greater than the role of the capsule and accounted for 77 % (SD 27 %, p = 0.006) and 70 % (SD 7 %, p = 0.009) of total distractive stability, respectively. The relative contribution of the capsule to distractive stability increased with progressive displacement, providing 41 % (SD 49 %) and 52 % (SD 53 %) of distractive stability at 3 and 5 mm of distraction, respectively. The maximal distraction force required to break the hip seal in the intact labral state (capsule removed) varied from 124 to 150 N. Labral tear, partial resection, and complete resection resulted in average maximal distraction forces of 76 % (SD 34 %), 29 % (SD 26 %), and 27 % (SD 22 %), respectively, compared to the intact state. Through type labral repairs resulted in significantly greater improvements (from the labral tear state) in maximal negative pressure generated, compared to looped type repairs (median increase; +32 vs. -9 %, p

Lithography requirements in complex VLSI device fabrication

International Nuclear Information System (INIS)

Wilson, A.D.

1985-01-01

Fabrication of complex very large scale integration (VLSI) circuits requires continual advances in lithography to satisfy: decreasing minimum linewidths, larger chip sizes, tighter linewidth and overlay control, increasing topography to linewidth ratios, higher yield demands, increased throughput, harsher device processing, lower lithography cost, and a larger part number set with quick turn-around time. Where optical, electron beam, x-ray, and ion beam lithography can be applied to judiciously satisfy the complex VLSI circuit fabrication requirements is discussed and those areas that are in need of major further advances are addressed. Emphasis will be placed on advanced electron beam and storage ring x-ray lithography

Larger groups of passerines are more efficient problem solvers in the wild

Science.gov (United States)

Morand-Ferron, Julie; Quinn, John L.

2011-01-01

Group living commonly helps organisms face challenging environmental conditions. Although a known phenomenon in humans, recent findings suggest that a benefit of group living in animals generally might be increased innovative problem-solving efficiency. This benefit has never been demonstrated in a natural context, however, and the mechanisms underlying improved efficiency are largely unknown. We examined the problem-solving performance of great and blue tits at automated devices and found that efficiency increased with flock size. This relationship held when restricting the analysis to naive individuals, demonstrating that larger groups increased innovation efficiency. In addition to this effect of naive flock size, the presence of at least one experienced bird increased the frequency of solving, and larger flocks were more likely to contain experienced birds. These findings provide empirical evidence for the “pool of competence” hypothesis in nonhuman animals. The probability of success also differed consistently between individuals, a necessary condition for the pool of competence hypothesis. Solvers had a higher probability of success when foraging with a larger number of companions and when using devices located near rather than further from protective tree cover, suggesting a role for reduced predation risk on problem-solving efficiency. In contrast to traditional group living theory, individuals joining larger flocks benefited from a higher seed intake, suggesting that group living facilitated exploitation of a novel food source through improved problem-solving efficiency. Together our results suggest that both ecological and social factors, through reduced predation risk and increased pool of competence, mediate innovation in natural populations. PMID:21930936

Shape accuracy requirements on starshades for large and small apertures

Science.gov (United States)

Shaklan, Stuart B.; Marchen, Luis; Cady, Eric

2017-09-01

Starshades have been designed to work with large and small telescopes alike. With smaller telescopes, the targets tend to be brighter and closer to the Solar System, and their putative planetary systems span angles that require starshades with radii of 10-30 m at distances of 10s of Mm. With larger apertures, the light-collecting power enables studies of more numerous, fainter systems, requiring larger, more distant starshades with radii >50 m at distances of 100s of Mm. Characterization using infrared wavelengths requires even larger starshades. A mitigating approach is to observe planets between the petals, where one can observe regions closer to the star but with reduced throughput and increased instrument scatter. We compare the starshade shape requirements, including petal shape, petal positioning, and other key terms, for the WFIRST 26m starshade and the HABEX 72 m starshade concepts, over a range of working angles and telescope sizes. We also compare starshades having rippled and smooth edges and show that their performance is nearly identical.

The irreducible floating hip: a unique presentation of a rare injury.

Science.gov (United States)

Tiedeken, Nathan C; Saldanha, Vilas; Handal, John; Raphael, James

2013-10-04

A floating hip injury occurs in the setting of poly-trauma and is a rare and difficult problem to manage. Floating hip injuries require vigilant attention not only to the osseous injuries but also the surrounding compartments and soft tissue envelope. We report the case of a 35-year-old male with a lower extremity posterior wall acetabular fracture, ipsilateral femoral shaft fracture and a postero-superior hip dislocation. Closed reduction failed, necessitating an open reduction internal fixation of his hip dislocation and acetabular fracture. The patient then developed a thigh compartment syndrome requiring a fasciotomy. Despite the obvious bony injuries, orthopedic surgeons must be vigilant of the neurovascular structures and soft tissues that have absorbed a great amount of force. A treatment plan should be formulated based on the status of the overlying soft tissue, fracture pattern and the patient's physiologic stability. Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author 2013.

Larger error signals in major depression are associated with better avoidance learning

Directory of Open Access Journals (Sweden)

James F eCavanagh

2011-11-01

Full Text Available The medial prefrontal cortex (mPFC is particularly reactive to signals of error, punishment, and conflict in the service of behavioral adaptation and it is consistently implicated in the etiology of Major Depressive Disorder (MDD. This association makes conceptual sense, given that MDD has been associated with hyper-reactivity in neural systems associated with punishment processing. Yet in practice, depression-related variance in measures of mPFC functioning often fails to relate to performance. For example, neuroelectric reflections of mediofrontal error signals are often found to be larger in MDD, but a deficit in post-error performance suggests that these error signals are not being used to rapidly adapt behavior. Thus, it remains unknown if depression-related variance in error signals reflects a meaningful alteration in the use of error or punishment information. However, larger mediofrontal error signals have also been related to another behavioral tendency: increased accuracy in avoidance learning. The integrity of this error-avoidance system remains untested in MDD. In this study, EEG was recorded as 21 symptomatic, drug-free participants with current or past MDD and 24 control participants performed a probabilistic reinforcement learning task. Depressed participants had larger mPFC EEG responses to error feedback than controls. The direct relationship between error signal amplitudes and avoidance learning accuracy was replicated. Crucially, this relationship was stronger in depressed participants for high conflict lose-lose situations, demonstrating a selective alteration of avoidance learning. This investigation provided evidence that larger error signal amplitudes in depression are associated with increased avoidance learning, identifying a candidate mechanistic model for hypersensitivity to negative outcomes in depression.

Larger miliolids of the Late Cretaceous and Paleogene seen through space and time

Directory of Open Access Journals (Sweden)

Vlasta Ćosović

2002-12-01

Full Text Available Spatial and temporal occurrences of the larger (complex miliolids are discussed to give more light on biostratigraphy and paleobiogeographic provinces distribution. Seven generaand 47 species from the Late Cretaceous to Oligocene inhabited shallow marine settings in the Indo-Pacific, Tethyan and Caribbean regions. Of all genera only four (Idalina, Periloculina, Pseudolacazina, Lacazina widespread throughout Tethys in theLate Cretaceous and Paleogene. Single occurrence of Lacazina was recorded further to east (Moluccas. By now the Late Cretaceous genus Adrahentina is known only from the Spain. The newcomer’s Eocene genera were Fabularia and Lacazinella. Fabularia reachedhigh diversity in species term in the Central and Western Tethys and occured as unique genus in Caribbean realm, too. Conversely, during the same period, Lacazinella spread over the southern border of Neo-Tethys reaching New Guinea.On the Adriatic – Dinaric Carbonate Platform, larger miliolids occurred from the Late Cretaceous to Cuisian, having the same biostratigraphically trends and distribution as contemporaneous larger miliolids from the Tethys.

Stereotactic Radiosurgery with Neoadjuvant Embolization of Larger Arteriovenous Malformations: An Institutional Experience

Directory of Open Access Journals (Sweden)

Richard Dalyai

2014-01-01

Full Text Available Objective. This study investigates the safety and efficacy of a multimodality approach combining staged endovascular embolizations with subsequent SRS for the management of larger AVMs. Methods. Ninety-five patients with larger AVMs were treated with staged endovascular embolization followed by SRS between 1996 and 2011. Results. The median volume of AVM in this series was 28 cm3 and 47 patients (48% were Spetzler-Martin grade IV or V. Twenty-seven patients initially presented with hemorrhage. Sixty-one patients underwent multiple embolizations while a single SRS session was performed in 64 patients. The median follow-up after SRS session was 32 months (range 9–136 months. Overall procedural complications occurred in 14 patients. There were 13 minor neurologic complications and 1 major complication (due to embolization while four patients had posttreatment hemorrhage. Thirty-eight patients (40% were cured radiographically. The postradiosurgery actuarial rate of obliteration was 45% at 5 years, 56% at 7 years, and 63% at 10 years. In multivariate analysis, larger AVM size, deep venous drainage, and the increasing number of embolization/SRS sessions were negative predictors of obliteration. The number of embolizations correlated positively with the number of stereotactic radiosurgeries (P<0.005. Conclusions. Multimodality endovascular and radiosurgical approach is an efficacious treatment strategy for large AVM.

Low local recurrence rate without postmastectomy radiation in node-negative breast cancer patients with tumors 5 cm and larger

International Nuclear Information System (INIS)

Floyd, Scott R.; Buchholz, Thomas A.; Haffty, Bruce G.; Goldberg, Saveli; Niemierko, Andrzej; Raad, Rita Abi; Oswald, Mary J.; Sullivan, Timothy; Strom, Eric A.; Powell, Simon N.; Katz, Angela; Taghian, Alphonse G.

2006-01-01

Purpose: To assess the need for adjuvant radiotherapy following mastectomy for patients with node-negative breast tumors 5 cm or larger. Methods and Materials: Between 1981 and 2002, a total of 70 patients with node-negative breast cancer and tumors 5 cm or larger were treated with mastectomy and adjuvant systemic therapies but without radiotherapy at three institutions. We retrospectively assessed rates and risk factors for locoregional failure (LRF), overall survival (OS), and disease-free survival (DFS) in these patients. Results: With a median follow-up of 85 months, the 5-year actuarial LRF rate was 7.6% (95% confidence interval, 3%-16%). LRF was primarily in the chest wall (4/5 local failures), and lymphatic-vascular invasion (LVI) was statistically significantly associated with LRF risk by the log-rank test (p = 0.017) and in Cox proportional hazards analysis (p 0.038). The 5-year OS and DFS rates were 83% and 86% respectively. LVI was also significantly associated with OS and DFS in both univariate and multivariate analysis. Conclusions: This series demonstrates a low LRF rate of 7.6% among breast cancer patients with node-negative tumors 5 cm and larger after mastectomy and adjuvant systemic therapy. Our data indicate that further adjuvant radiation therapy to increase local control may not be indicated by tumor size alone in the absence of positive lymph nodes. LVI was significantly associated with LRF in our series, indicating that patients with this risk factor require careful consideration with regard to further local therapy

More ‘altruistic’ punishment in larger societies

Science.gov (United States)

Marlowe, Frank W; Berbesque, J. Colette; Barr, Abigail; Barrett, Clark; Bolyanatz, Alexander; Cardenas, Juan Camilo; Ensminger, Jean; Gurven, Michael; Gwako, Edwins; Henrich, Joseph; Henrich, Natalie; Lesorogol, Carolyn; McElreath, Richard; Tracer, David

2007-01-01

If individuals will cooperate with cooperators, and punish non-cooperators even at a cost to themselves, then this strong reciprocity could minimize the cheating that undermines cooperation. Based upon numerous economic experiments, some have proposed that human cooperation is explained by strong reciprocity and norm enforcement. Second-party punishment is when you punish someone who defected on you; third-party punishment is when you punish someone who defected on someone else. Third-party punishment is an effective way to enforce the norms of strong reciprocity and promote cooperation. Here we present new results that expand on a previous report from a large cross-cultural project. This project has already shown that there is considerable cross-cultural variation in punishment and cooperation. Here we test the hypothesis that population size (and complexity) predicts the level of third-party punishment. Our results show that people in larger, more complex societies engage in significantly more third-party punishment than people in small-scale societies. PMID:18089534

How do environmental policies fit within larger strategic planning processes

OpenAIRE

Crowe, Lynn

2015-01-01

This chapter explores how environmental policies fit within larger strategic processes relevant to sport management and development. It identifies key policy areas such as environmental impact assessment, sustainable land use planning, environmental protection and visitor impact management. Good practice and guidelines which will enable sport managers to integrate their work with these environmental policies are explored. Detailed guidance on design and longer term management and maintenance ...

Great tits provided with ad libitum food lay larger eggs when exposed to colder temperatures

NARCIS (Netherlands)

Schaper, S.V.; Visser, M.E.

2013-01-01

The amount of nutrients deposited into a bird egg varies both between and within clutches of the same female. Larger eggs enhance offspring traits, but as a tradeoff, laying large eggs also infers energetic costs to the female. Income breeders usually lay larger eggs later in the season, when

Possible Evolution of the Pulsar Braking Index from Larger than Three to About One

Energy Technology Data Exchange (ETDEWEB)

Tong, H. [School of Physics and Electronic Engineering, Guangzhou University, 510006 Guangzhou (China); Kou, F. F., E-mail: htong_2005@163.com [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi, Xinjiang 830011 (China)

2017-03-10

The coupled evolution of pulsar rotation and inclination angle in the wind braking model is calculated. The oblique pulsar tends to align. The pulsar alignment affects its spin-down behavior. As a pulsar evolves from the magneto-dipole radiation dominated case to the particle wind dominated case, the braking index first increases and then decreases. In the early time, the braking index may be larger than three. During the following long time, the braking index is always smaller than three. The minimum braking index is about one. This can explain the existence of a high braking index larger than three and a low braking index simultaneously. The pulsar braking index is expected to evolve from larger than three to about one. The general trend is for the pulsar braking index to evolve from the Crab-like case to the Vela-like case.

Possible Evolution of the Pulsar Braking Index from Larger than Three to About One

International Nuclear Information System (INIS)

Tong, H.; Kou, F. F.

2017-01-01

The coupled evolution of pulsar rotation and inclination angle in the wind braking model is calculated. The oblique pulsar tends to align. The pulsar alignment affects its spin-down behavior. As a pulsar evolves from the magneto-dipole radiation dominated case to the particle wind dominated case, the braking index first increases and then decreases. In the early time, the braking index may be larger than three. During the following long time, the braking index is always smaller than three. The minimum braking index is about one. This can explain the existence of a high braking index larger than three and a low braking index simultaneously. The pulsar braking index is expected to evolve from larger than three to about one. The general trend is for the pulsar braking index to evolve from the Crab-like case to the Vela-like case.

Patterns of pelvic and acetabular injury among Sudanese patients ...

African Journals Online (AJOL)

, S Idris. Abstract. Background: Most of major pelvic fractures result from very high energy trauma and require urgent hospital treatment. However more minor, stable fractures may only require a period of rest and analgesia followed by gradual ...

Speaker Input Variability Does Not Explain Why Larger Populations Have Simpler Languages.

Science.gov (United States)

Atkinson, Mark; Kirby, Simon; Smith, Kenny

2015-01-01

A learner's linguistic input is more variable if it comes from a greater number of speakers. Higher speaker input variability has been shown to facilitate the acquisition of phonemic boundaries, since data drawn from multiple speakers provides more information about the distribution of phonemes in a speech community. It has also been proposed that speaker input variability may have a systematic influence on individual-level learning of morphology, which can in turn influence the group-level characteristics of a language. Languages spoken by larger groups of people have less complex morphology than those spoken in smaller communities. While a mechanism by which the number of speakers could have such an effect is yet to be convincingly identified, differences in speaker input variability, which is thought to be larger in larger groups, may provide an explanation. By hindering the acquisition, and hence faithful cross-generational transfer, of complex morphology, higher speaker input variability may result in structural simplification. We assess this claim in two experiments which investigate the effect of such variability on language learning, considering its influence on a learner's ability to segment a continuous speech stream and acquire a morphologically complex miniature language. We ultimately find no evidence to support the proposal that speaker input variability influences language learning and so cannot support the hypothesis that it explains how population size determines the structural properties of language.

Larger amygdala volume in first-degree relatives of patients with major depression

Directory of Open Access Journals (Sweden)

Nina Romanczuk-Seiferth

2014-01-01

Conclusions: Larger gray matter volume in healthy relatives of MDD patients point to a possible vulnerability mechanism in MDD etiology and therefore extend knowledge in the field of high-risk approaches in MDD.

Size selectivity of commercial (300 MC) and larger square mesh top ...

African Journals Online (AJOL)

In the present study, size selectivity of a commercial (300 MC) and a larger square mesh top panel (LSMTPC) codend for blue whiting (Micromesistius poutassou) were tested on a commercial trawl net in the international waters between Turkey and Greece. Trawling, performed during daylight was carried out at depths ...

Base stock policies with degraded service to larger orders

DEFF Research Database (Denmark)

Du, Bisheng; Larsen, Christian

We study an inventory system controlled by a base stock policy assuming a compound renewal demand process. We extend the base stock policy by incorporating rules for degrading the service of larger orders. Two specific rules are considered, denoted Postpone(q,t) and Split(q), respectively. The aim...... of using these rules is to achieve a given order fill rate of the regular orders (those of size less than or equal to the parameter q) having less inventory. We develop mathematical expressions for the performance measures order fill rate (of the regular orders) and average on-hand inventory level. Based...

Comparison between smaller ruptured intracranial aneurysm and larger un-ruptured intracranial aneurysm: gene expression profile analysis.

Science.gov (United States)

Li, Hao; Li, Haowen; Yue, Haiyan; Wang, Wen; Yu, Lanbing; ShuoWang; Cao, Yong; Zhao, Jizong

2017-07-01

As it grows in size, an intracranial aneurysm (IA) is prone to rupture. In this study, we compared two extreme groups of IAs, ruptured IAs (RIAs) smaller than 10 mm and un-ruptured IAs (UIAs) larger than 10 mm, to investigate the genes involved in the facilitation and prevention of IA rupture. The aneurismal walls of 6 smaller saccular RIAs (size smaller than 10 mm), 6 larger saccular UIAs (size larger than 10 mm) and 12 paired control arteries were obtained during surgery. The transcription profiles of these samples were studied by microarray analysis. RT-qPCR was used to confirm the expression of the genes of interest. In addition, functional group analysis of the differentially expressed genes was performed. Between smaller RIAs and larger UIAs, 101 genes and 179 genes were significantly over-expressed, respectively. In addition, functional group analysis demonstrated that the up-regulated genes in smaller RIAs mainly participated in the cellular response to metal ions and inorganic substances, while most of the up-regulated genes in larger UIAs were involved in inflammation and extracellular matrix (ECM) organization. Moreover, compared with control arteries, inflammation was up-regulated and muscle-related biological processes were down-regulated in both smaller RIAs and larger UIAs. The genes involved in the cellular response to metal ions and inorganic substances may facilitate the rupture of IAs. In addition, the healing process, involving inflammation and ECM organization, may protect IAs from rupture.

A study on iliac index in Koran children

International Nuclear Information System (INIS)

Kim, Chu Wan

1973-01-01

Abnormal pelvic configuration with resultant abnormal value of acetabular angle, iliac angle and iliac index is well known in some congenital and hereditary diseases and its measurement is valuable in establishing diagnosis in these diseases. Considering that there is no available standard values of Korean children, we measured acetabular angles, iliac angles and iliac indices in 150 normal Korean children, 10 cases of congenital dislocation of hip and 2 cases of mongolism. The results are as follows: 1. The values of acetabular angle, iliac angle and lilac index are significantly lower than those of American children. 2. Significant increase in acetabular angle is observed in patients with congenital dislocation of hip and significant decrease in iliac index in patients with mongolism is observed. 3. Iliac index seems to be more reliable than either of acetabular angle and iliac angle in the detection of abnormal pelvic contuor in patients with mongolism. We considered that the pelvic mensuration should be done in large number of normal and patients and further study in this fields should be carried out

Larger foraminifera from a relict structure off Karwar western Indian continental margin

Digital Repository Service at National Institute of Oceanography (India)

Setty, M.G.A.P.

of such water masses having been present in the region. Among the larger forms, @iAmphistegina bicirculata, A. radiata@@ var. @ipapillosa@@ and @iOperculina ammonoides@@ indicate mixing, while @iNummulites cumingii@@ and @iBorelis schlumbergeri@@ were relict...

Comparison of femoroacetabular impingement-related radiographic features in a convenience sample of Japanese patients with and without herniation pits

International Nuclear Information System (INIS)

Mineta, Kazuaki; Goto, Tomohiro; Wada, Keizo; Tamaki, Yasuaki; Hamada, Daisuke; Higashino, Kosaku; Sairyo, Koichi

2016-01-01

To examine the prevalence of herniation pits (HPs) and to evaluate differences in radiographic features related to femoroacetabular impingement - a hip disorder with abnormal abutment between the acetabulum and femur - between hips with and without HPs in a convenience sample of Japanese patients. We reviewed 1,178 hips on each side (695 men, 483 women; mean age, 58.2 years) using computed tomographic images. The radiological assessments of hip morphology were performed by measuring the lateral center edge angle, acetabular index, acetabular version, alpha angle, and femoral head-neck offset. HPs were defined as the round or oval cystic lesions surrounded by sclerotic bone located below the anterior femoral neck cortex. Intraclass and interclass reproducibility of all radiographic measurements was acceptable (ICC: 0.71-0.98). The prevalence of HPs was 13.9 % in all subjects and was significantly higher in men (18.1 %) than in women (7.8 %; p < 0.001). HPs were larger in male (p < 0.001) and elderly subjects (p < 0.005). In subjects with HPs, the alpha angle was larger and femoral head-neck offset and offset ratio were smaller in the cohort overall and in men. Logistic regression analysis revealed the association between radiological cam-type FAI and HPs in all subjects (odds ratio: 1.86, p < 0.001). We revealed the prevalence of HPs and showed it has a predilection for men in this Japanese cohort. Femoral head asphericity or small head-neck offset was more common in subjects with HPs than those without HPs. (orig.)

Larger foraminifera distribution on a mesotrophic carbonate shelf in SW Sulawesi (Indonesia)

NARCIS (Netherlands)

Renema, W.; Troelstra, S.R.

2001-01-01

Larger symbiont bearing foraminifera typically live in shallow tropical seas. In this study the fauna composition of patch reefs scattered over the Spermonde Shelf (SW Sulawesi, Indonesia), a mesotrophic carbonate shelf, is examined. The foraminiferal fauna of the Spermonde Shelf is characterised by

Electromagnetic Compatibility (EMC) Requirements for Military and Commercial Equipment

Science.gov (United States)

2009-09-01

Commercial off-the shelf (COTS) use also provides access to what has become a much larger industrial base. With these goals in mind, the Secretary of...in 1999 by the UFO satellites. Additional protected satellite systems include the MILSTAR and Air Force Satellite Communications (AFSATCOM) systems...to what has become a much larger industrial base. With these goals in mind, the Secretary of Defense issued a directive in June 1994 requiring the

78 FR 18902 - Defining Larger Participants of the Student Loan Servicing Market

Science.gov (United States)

2013-03-28

... BUREAU OF CONSUMER FINANCIAL PROTECTION 12 CFR Part 1090 [Docket No. CFPB-2013-0005] RIN 3170-AA35... Protection. ACTION: Proposed rule; request for public comment. SUMMARY: The Bureau of Consumer Financial Protection (Bureau or CFPB) proposes to amend the regulation defining larger participants of certain consumer...

Action video game players and deaf observers have larger Goldmann visual fields.

Science.gov (United States)

Buckley, David; Codina, Charlotte; Bhardwaj, Palvi; Pascalis, Olivier

2010-03-05

We used Goldmann kinetic perimetry to compare how training and congenital auditory deprivation may affect the size of the visual field. We measured the ability of action video game players and deaf observers to detect small moving lights at various locations in the central (around 30 degrees from fixation) and peripheral (around 60 degrees ) visual fields. Experiment 1 found that 10 habitual video game players showed significantly larger central and peripheral field areas than 10 controls. In Experiment 2 we found that 13 congenitally deaf observers had significantly larger visual fields than 13 hearing controls for both the peripheral and central fields. Here the greatest differences were found in the lower parts of the fields. Comparison of the two groups showed that whereas VGP players have a more uniform increase in field size in both central and peripheral fields deaf observers show non-uniform increases with greatest increases in lower parts of the visual field.

Analysis of the acetabulum by CT scan in Japanese with osteoarthritis of the hip

International Nuclear Information System (INIS)

Ishibashi, Masanori

1997-01-01

The morphology of the acetabulum was analyzed by CT scan in 66 Japanese patients with osteoarthritis of the hip mainly following congenital dislocation or dysplasia. The CT scan data was analyzed to standardize the pelvic inclination in all directions. In these patients, the acetabular floor had thickened and the acetabulum was located in the anterolateral portion. The bilateral difference in the acetabular anteversion angle was not different between patients and normal individuals, but the acetabular sector angle in patients was smaller than in the normal subjects. As the stage of osteoarthritis of the hip advanced, the thickness of the acetabular floor in the center and posterior portions and the anterior sector angle increased, and the lateralization of the acetabulum advanced, but the anteversion angle decreased. A bone-forming change is characteristic of the anterior acetabulum and acetabular fossa in the center and posterior portions in Japanese patients with osteoarthritis of the hip. In comparison with data obtained by standard radiography, these changes detected by CT scan corresponded to an increase of the width of a tear drop, the lateralization of the femoral head and the lack of the support of the femoral head from the acetabulum. (author)

Analysis of the acetabulum by CT scan in Japanese with osteoarthritis of the hip

Energy Technology Data Exchange (ETDEWEB)

Ishibashi, Masanori [Keio Univ., Tokyo (Japan). School of Medicine

1997-11-01

The morphology of the acetabulum was analyzed by CT scan in 66 Japanese patients with osteoarthritis of the hip mainly following congenital dislocation or dysplasia. The CT scan data was analyzed to standardize the pelvic inclination in all directions. In these patients, the acetabular floor had thickened and the acetabulum was located in the anterolateral portion. The bilateral difference in the acetabular anteversion angle was not different between patients and normal individuals, but the acetabular sector angle in patients was smaller than in the normal subjects. As the stage of osteoarthritis of the hip advanced, the thickness of the acetabular floor in the center and posterior portions and the anterior sector angle increased, and the lateralization of the acetabulum advanced, but the anteversion angle decreased. A bone-forming change is characteristic of the anterior acetabulum and acetabular fossa in the center and posterior portions in Japanese patients with osteoarthritis of the hip. In comparison with data obtained by standard radiography, these changes detected by CT scan corresponded to an increase of the width of a tear drop, the lateralization of the femoral head and the lack of the support of the femoral head from the acetabulum. (author)

A new tilt on pelvic radiographs: a pilot study

Energy Technology Data Exchange (ETDEWEB)

Richards, P.J. [North Staffordshire Royal Infirmary, Department of Radiology, Stoke-on-Trent, Staffordshire (United Kingdom); Pattison, J.M. [University Hospital of North Staffordshire, Department of Radiology, Stoke on Trent (United Kingdom); Belcher, J. [Keele University, Department of Mathematics, Keele, Staffordshire (United Kingdom); DeCann, R.W. [IMECS, Department of Radiology, Market Drayton, Shropshire (United Kingdom); Anderson, Suzanne [University of Melbourne, Department of Radiology, Melbourne (Australia); Wynn-Jones, C. [University Hospital of North Staffordshire, Department of Orthopaedic Surgery, Stoke on Trent (United Kingdom)

2009-02-15

The aim of this study was to evaluate pelvic tilt on commonly performed measurements on radiography in primary protrusio acetabuli and developmental dysplasia of the hip. A dry assembled pelvis and spine skeleton was positioned in an isocentric skull unit and films exposed with increasing degrees of angulation of pelvic tilt. The films were then read by two independent readers for seven different measurements used to evaluate the hips and acetabular: acetabular line to ilioischial line, teardrop appearance, intercristal/intertuberous ratio, co-ordinates of femoral head, centre edge angle, acetabular depth/width ratio and acetabular angle. There was so much variation in the protrusio results that no formal recommendation of any standard radiographic test can be given. Only the inter tuberous distance is not effected by pelvic tilt. The acetabular angles for developmental dysplasia of the hip showed the most potential with pelvic tilt below 15 . As pelvic tilt increases, measurements used in protusio become unreliable, and computed tomography/magnetic resonance imaging are probably going to be more accurate as one can directly visualise pelvic intrusion. We recommend a lateral view to assess the degree of pelvic tilt in patients with protrusion to ensure these measurements are valid. (orig.)

Larger foraminifera of the Devil's Den and Blue Hole sinkholes, Florida

Science.gov (United States)

Cotton, Laura J.; Eder, Wolfgang; Floyd, James

2018-03-01

Shallow-water carbonate deposits are well-known from the Eocene of the US Gulf Coast and Caribbean. These deposits frequently contain abundant larger benthic foraminifera (LBF). However, whilst integrated stratigraphic studies have helped to refine the timing of LBF overturning events within the Tethys and Indo-Pacific regions with respect to global bio- and chemo-stratigraphic records, little recent work has been carried out in the Americas. The American LBF assemblages are distinctly different from those of Europe and the Indo-Pacific. It is therefore essential that the American bio-province is included in studies of LBF evolution, biodiversity and climate events to understand these processes on a global scale.Here we present the LBF ranges from two previously unpublished sections spanning 35 and 29 m of the upper Eocene Ocala limestone, as the early stages of a larger project addressing the taxonomy and biostratigraphy of the LBF of Florida. The study indicates that the lower member of the Ocala limestone may be Bartonian rather than Priabonian in age, with implications for the biostratigraphy of the region. In addition, the study highlights the need for multiple sites to assess the LBF assemblages and fully constrain ranges across Florida and the US Gulf and suggests potential LBF events for future integrated stratigraphic study.

Bony morphology of the hip in professional ballet dancers compared to athletes.

Science.gov (United States)

Mayes, Susan; Ferris, April-Rose; Smith, Peter; Garnham, Andrew; Cook, Jill

2017-07-01

To compare hip bony morphology between ballet dancers and a sporting control group and to determine the relationship with hip pain. Thirty-three professional ballet dancers and 33 age- and sex-matched athletes completed questionnaires, including the Copenhagen Hip and Groin Outcome Score (HAGOS), and underwent clinical testing and 3.0-T magnetic resonance imaging to measure acetabular coverage with lateral centre edge angles, femoral head-neck junction concavity with alpha angles at anterior and superior positions, femoral neck-shaft angles, and acetabular version angles. Bony morphological measures fell within normal ranges. Dancers had higher neck-shaft angles (dancers 134.6 ± 4.6°/athletes130.8 ± 4.7°, p = 0.002), lower acetabular version angles (13.5 ± 4.7°/17.1 ± 4.7°, p = 0.003), lower superior alpha angles (38.9 ± 6.9°/46.7 ± 10.6°, p ballet dancers have hip bony morphology that differentiates them from athletes. Hip pain correlated poorly with bony morphology. • Ballet dancers have hip bony morphology that may allow extreme hip motion. • Morphological parameter means fell within normal reference intervals in dancers. • Bony morphology correlates poorly with hip pain. • The risk of hip injury due to abnormal morphology requires prospective studies.

MRI findings of the residual subluxation after reduction of developmental dysplasia of the hip

International Nuclear Information System (INIS)

Wakabayashi, Kenjirou; Wada, Ikuo; Horiuchi, Osamu; Otsuka, Takanobu

2007-01-01

After reduction of developmental dysplasia of the hip (DDH), not a few patients suffer from residual subluxation as well as acetabular dysplasia. Corrective surgery for these residual subluxations is sometimes performed before school-child age. It is occasionally difficult to determine whether the patient is candidate for the corrective surgery in the case with minor morphologic aberration. Therefore, we studied various MRI findings in residual subluxation, and examined if these MRI findings have an effect on natural courses such as growth or concentricity of the hip joint after reduction for DDH. The usefulness of MRI for determining the indication for the corrective surgery was also investigated. We studied 235 patients who underwent primary treatment for DDH during the past decade (between October, 1988 and September, 1998). Of the 235 patients, we studied 23 patients (23 cases; all unilateral cases) who showed residual subluxation and whose MR images were taken when they were around 3 years old, and during a follow-up period was available. Corrective surgery is performed in 11 patients, whereas the remaining 12 patients were conservatively observed the course of the residual subluxation. We investigated the existence of high signal intensity area (hereinafter referred to as HSIA) within the weight-bearing acetabular cartilage on T2-weighted MR coronal section images. Furthermore, conservatively observed patients were divided into two groups according to T2-weighted MR images. Based on simple X-ray images with time in both groups, the acetabular angle and the CE angle were measured. As results, many patients with residual subluxation showed localized HSIA in the weight-bearing acetabular cartilage on T2-weighted MR images. Although all patients who underwent corrective surgery showed HSIA, HSIA disappeared or decreased after the surgery. Of patients who were conservatively observed the course of the residual subluxation, patients showed HSIA on MR image had poor

What Is the Rerevision Rate After Revising a Hip Resurfacing Arthroplasty? Analysis From the AOANJRR.

Science.gov (United States)

Wong, James Min-Leong; Liu, Yen-Liang; Graves, Stephen; de Steiger, Richard

2015-11-01

More than 15,000 primary hip resurfacing arthroplasties have been recorded by the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) with 884 primary procedures requiring revision for reasons other than infection, a cumulative percent revision rate at 12 years of 11%. However, few studies have reported the survivorship of these revision procedures. (1) What is the cumulative percent rerevision rate for revision procedures for failed hip resurfacings? (2) Is there a difference in rerevision rate among different types of revision or bearing surfaces? The AOANJRR collects data on all primary and revision hip joint arthroplasties performed in Australia and after verification against health department data, checking of unmatched procedures, and subsequent retrieval of unreported procedures is able to obtain an almost complete data set relating to hip arthroplasty in Australia. Revision procedures are linked to the known primary hip arthroplasty. There were 15,360 primary resurfacing hip arthroplasties recorded of which 884 had undergone revision and this was the cohort available to study. The types of revisions were acetabular only, femoral only, or revision of both acetabular and femoral components. With the exception of the acetabular-only revisions, all revisions converted hip resurfacing arthroplasties to conventional (stemmed) total hip arthroplasties (THAs). All initial revisions for infection were excluded. The survivorship of the different types of revisions and that of the different bearing surfaces used were estimated using the Kaplan-Meier method and compared using Cox proportional hazard models. Cumulative percent revision was calculated by determining the complement of the Kaplan-Meier survivorship function at that time multiplied by 100. Of the 884 revisions recorded, 102 underwent further revision, a cumulative percent rerevision at 10 years of 26% (95% confidence interval, 19.6-33.5). There was no difference in the rate of

Bipolar hip arthroplasty for avascular necrosis of femoral head in young adults

Directory of Open Access Journals (Sweden)

Baldev Dudani

2015-01-01

Conclusion: Bipolar hip arthroplasty (BHA using tight fitting cup and acetabular reaming in AVN hip has a low incidence of groin pain, acetabular erosion and revision in midterm followup. Good outcome and mid term survival can be achieved irrespective of the Ficat Stage.

Behavior and Body Patterns of the Larger Pacific Striped Octopus.

Science.gov (United States)

Caldwell, Roy L; Ross, Richard; Rodaniche, Arcadio; Huffard, Christine L

2015-01-01

Over thirty years ago anecdotal accounts of the undescribed Larger Pacific Striped Octopus suggested behaviors previously unknown for octopuses. Beak-to-beak mating, dens shared by mating pairs, inking during mating and extended spawning were mentioned in publications, and enticed generations of cephalopod biologists. In 2012-2014 we were able to obtain several live specimens of this species, which remains without a formal description. All of the unique behaviors listed above were observed for animals in aquaria and are discussed here. We describe the behavior, body color patterns, and postures of 24 adults maintained in captivity. Chromatophore patterns of hatchlings are also shown.

Framing the Discussion: Elections as Components of Larger Political and Cultural Geographies

Science.gov (United States)

Knopp, Larry

2016-01-01

It is important to remember that elections are but one piece--albeit an important one--of much larger processes of politics and governance. Moreover, in the United States they are increasingly implicated in the construction of identities and places. What goes on in the course of electoral politics (creating electoral systems and voting districts,…

Demonstrating the value of larger ensembles in forecasting physical systems

Directory of Open Access Journals (Sweden)

Reason L. Machete

2016-12-01

Full Text Available Ensemble simulation propagates a collection of initial states forward in time in a Monte Carlo fashion. Depending on the fidelity of the model and the properties of the initial ensemble, the goal of ensemble simulation can range from merely quantifying variations in the sensitivity of the model all the way to providing actionable probability forecasts of the future. Whatever the goal is, success depends on the properties of the ensemble, and there is a longstanding discussion in meteorology as to the size of initial condition ensemble most appropriate for Numerical Weather Prediction. In terms of resource allocation: how is one to divide finite computing resources between model complexity, ensemble size, data assimilation and other components of the forecast system. One wishes to avoid undersampling information available from the model's dynamics, yet one also wishes to use the highest fidelity model available. Arguably, a higher fidelity model can better exploit a larger ensemble; nevertheless it is often suggested that a relatively small ensemble, say ~16 members, is sufficient and that larger ensembles are not an effective investment of resources. This claim is shown to be dubious when the goal is probabilistic forecasting, even in settings where the forecast model is informative but imperfect. Probability forecasts for a ‘simple’ physical system are evaluated at different lead times; ensembles of up to 256 members are considered. The pure density estimation context (where ensemble members are drawn from the same underlying distribution as the target differs from the forecasting context, where one is given a high fidelity (but imperfect model. In the forecasting context, the information provided by additional members depends also on the fidelity of the model, the ensemble formation scheme (data assimilation, the ensemble interpretation and the nature of the observational noise. The effect of increasing the ensemble size is quantified by

Larger eggs in resident brown trout living in sympatry with anadromous brown trout

DEFF Research Database (Denmark)

Olofsson, H.; Mosegaard, Henrik

1999-01-01

Freshwater resident brown trout (Salmo trutta L.) in the stream Jorlandaan (southwestern Sweden) had larger eggs (range of actual mean egg wet weights, 65.9-108.5 mg) than both sympatric migratory trout (76.8-84.2 mg) and trout from five other Swedish streams with allopatric resident (23.7-80.1 mg......) or migratory populations (44.5-121.9 mg), after accounting for differences in body size. In Jorlandaan, some resident females even had a larger absolute mean egg weight than any of the migratory females found in the stream Resident trout had low absolute fecundity, and our data suggest that resident females...... in Jorlandan produce large eggs at the expense of their fecundity The extremely large relative egg size in resident Jorlandaan females suggests that the production of large offspring enhances fitness, possibly through increased fry survival....

Prevalence of malformations of the hip joint and their relationship to sex, groin pain, and risk of osteoarthritis: a population-based survey

DEFF Research Database (Denmark)

Gosvig, Kasper Kjaerulf; Jacobsen, Steffen; Sonne-Holm, Stig

2010-01-01

of Østerbro, Copenhagen, Denmark. The inclusion criteria for this study were met by 1332 men and 2288 women. On the basis of radiographic criteria, the hips were categorized as being without malformations or as having an abnormality consisting of a deep acetabular socket, a pistol grip deformity......, or a combination of a deep acetabular socket and a pistol grip deformity. Hip osteoarthritis was defined radiographically as a minimum joint-space width of 0.13). A deep acetabular socket was a significant risk factor for the development of osteoarthritis (risk ratio, 2.4), as was a pistol grip deformity (risk...... was 71.0% in men with hip osteoarthritis and 36.6% in women with hip osteoarthritis. CONCLUSIONS: In our study population, a deep acetabular socket and a pistol grip deformity were common radiographic findings and were associated with an increased risk of hip osteoarthritis. The high prevalence...

Prevalence of malformations of the hip joint and their relationship to sex, groin pain, and risk of osteoarthritis: a population-based survey

DEFF Research Database (Denmark)

Gosvig, Kasper Kjaerulf; Jacobsen, Steffen; Sonne-Holm, Stig

2010-01-01

ratio, 2.2). Acetabular dysplasia and the subject's sex were not found to be significant risk factors for the development of hip osteoarthritis (p = 0.053 and p = 0.063, respectively). The prevalence of hip osteoarthritis was 9.5% in men and 11.2% in women. The prevalence of concomitant malformations...... of Østerbro, Copenhagen, Denmark. The inclusion criteria for this study were met by 1332 men and 2288 women. On the basis of radiographic criteria, the hips were categorized as being without malformations or as having an abnormality consisting of a deep acetabular socket, a pistol grip deformity......, or a combination of a deep acetabular socket and a pistol grip deformity. Hip osteoarthritis was defined radiographically as a minimum joint-space width of 0.13). A deep acetabular socket was a significant risk factor for the development of osteoarthritis (risk ratio, 2.4), as was a pistol grip deformity (risk...

Developing Renewable Energy Projects Larger Than 10 MWs at Federal Facilities

Energy Technology Data Exchange (ETDEWEB)

None

2013-03-01

To accomplish Federal goals for renewable energy, sustainability, and energy security, large-scale renewable energy projects must be developed and constructed on Federal sites at a significant scale with significant private investment. For the purposes of this Guide, large-scale Federal renewable energy projects are defined as renewable energy facilities larger than 10 megawatts (MW) that are sited on Federal property and lands and typically financed and owned by third parties.1 The U.S. Department of Energy’s Federal Energy Management Program (FEMP) helps Federal agencies meet these goals and assists agency personnel navigate the complexities of developing such projects and attract the necessary private capital to complete them. This Guide is intended to provide a general resource that will begin to develop the Federal employee’s awareness and understanding of the project developer’s operating environment and the private sector’s awareness and understanding of the Federal environment. Because the vast majority of the investment that is required to meet the goals for large-scale renewable energy projects will come from the private sector, this Guide has been organized to match Federal processes with typical phases of commercial project development. FEMP collaborated with the National Renewable Energy Laboratory (NREL) and professional project developers on this Guide to ensure that Federal projects have key elements recognizable to private sector developers and investors. The main purpose of this Guide is to provide a project development framework to allow the Federal Government, private developers, and investors to work in a coordinated fashion on large-scale renewable energy projects. The framework includes key elements that describe a successful, financially attractive large-scale renewable energy project. This framework begins the translation between the Federal and private sector operating environments. When viewing the overall

Influence of hip dysplasia on the development of osteoarthritis of the hip

NARCIS (Netherlands)

A.M. Lievense (Annet); S.M. Bierma-Zeinstra (Sita); A.P. Verhagen (Arianne); J.A.N. Verhaar (Jan); B.W. Koes (Bart)

2004-01-01

textabstractBackground: It has been suggested that in some patients with primary hip osteoarthritis (OA), the disease occurs as a consequence of acetabular dysplasia or hip dysplasia (HD). Objective: To carry out a systematic review to investigate the association between acetabular dysplasia and hip

Analysis of {sup 18} F-FDG uptake patterns in PET for diagnosis of septic and aseptic loosening after total hip arthroplasty

Energy Technology Data Exchange (ETDEWEB)

Cremerius, U.; Niethard, F.U. [Rheinisch-Westfaelische Technische Hochschule Aachen (Germany). Klinik fuer Nuklearmedizin; Mumme, T.; Reinartz, P.; Wirtz, D. [Rheinisch-Westfaelische Technische Hochschule Aachen (Germany). Orthopaedische Klinik; Buell, U.

2003-12-01

Aim: Identification of typical patterns for fluorodeoxyglucose (FDG) uptake in positron emission tomography (PET) to detect aseptic loosening of hip prosthesis (acetabular and/or femoral component) and prosthetic infection. Methods: 18 patients with painful hip prosthesis underwent PET using a dedicated full ring scanner after application of 200-300 MBq FDG. The interface between bone and surrounding soft tissue or bone as displayed on coronal slices was divided into 12 segments in accordance with the classifications of Delee and Gruen. FDG uptake in each of the segments was scored (0-3) by two independent observers. Intraoperative findings were regarded as the gold standard. Results: After surgical revision 14 acetabular components and 9 femoral components were found to be loose and prosthetic infection was present in 7 prostheses. Loosening of the acetabular component was correlated to enhanced uptake in the middle of the acetabular interface, while loosening of the femoral component was correlated to enhanced uptake in the proximal and middle segment of the lateral femoral interface and the proximal segment of the medial femoral interface. A similar pattern was found in prosthetic infection with high uptake along the middle portion of the lateral femoral interface. In 6 of 7 infected prostheses loosening of the acetabular and of the femoral component was present. Taking the typical uptake patterns as criteria for loosening and grade 3 uptake as an additional criterion for septic loosening the accuracy of PET imaging in the detection of loosening of the acetabular or the femoral component and of prosthetic infection was 72, 78 and 89%, respectively. Conclusion: This pilot study presents FDG-PET as a promising diagnostic tool for patients with painful hip prostheses. Its clinical value should be evaluated in a larger patient population. (orig.) [German] Ziel: Identifikation von Befundmustern in der Positronenemissionstomographie (PET) mit {sup 18}F

Historical Carbon Dioxide Emissions Caused by Land-Use Changes are Possibly Larger than Assumed

Science.gov (United States)

Arneth, A.; Sitch, S.; Pongratz, J.; Stocker, B. D.; Ciais, P.; Poulter, B.; Bayer, A. D.; Bondeau, A.; Calle, L.; Chini, L. P.;

Sequencing Larger Intact Proteins (30-70 kDa) with Activated Ion Electron Transfer Dissociation

Science.gov (United States)

Riley, Nicholas M.; Westphall, Michael S.; Coon, Joshua J.

2018-01-01

The analysis of intact proteins via mass spectrometry can offer several benefits to proteome characterization, although the majority of top-down experiments focus on proteoforms in a relatively low mass range (AI-ETD) to proteins in the 30-70 kDa range. AI-ETD leverages infrared photo-activation concurrent to ETD reactions to improve sequence-informative product ion generation. This method generates more product ions and greater sequence coverage than conventional ETD, higher-energy collisional dissociation (HCD), and ETD combined with supplemental HCD activation (EThcD). Importantly, AI-ETD provides the most thorough protein characterization for every precursor ion charge state investigated in this study, making it suitable as a universal fragmentation method in top-down experiments. Additionally, we highlight several acquisition strategies that can benefit characterization of larger proteins with AI-ETD, including combination of spectra from multiple ETD reaction times for a given precursor ion, multiple spectral acquisitions of the same precursor ion, and combination of spectra from two different dissociation methods (e.g., AI-ETD and HCD). In all, AI-ETD shows great promise as a method for dissociating larger intact protein ions as top-down proteomics continues to advance into larger mass ranges. [Figure not available: see fulltext.

Groups have a larger cognitive capacity than individuals.

Science.gov (United States)

Sasaki, Takao; Pratt, Stephen C

2012-10-09

Increasing the number of options can paradoxically lead to worse decisions, a phenomenon known as cognitive overload [1]. This happens when an individual decision-maker attempts to digest information exceeding its processing capacity. Highly integrated groups, such as social insect colonies, make consensus decisions that combine the efforts of many members, suggesting that these groups can overcome individual limitations [2-4]. Here we report that an ant colony choosing a new nest site is less vulnerable to cognitive overload than an isolated ant making this decision on her own. We traced this improvement to differences in individual behavior. In whole colonies, each ant assesses only a small subset of available sites, and the colony combines their efforts to thoroughly explore all options. An isolated ant, on the other hand, must personally assess a larger number of sites to approach the same level of option coverage. By sharing the burden of assessment, the colony avoids overtaxing the abilities of its members. Copyright © 2012 Elsevier Ltd. All rights reserved.

Investigation of CT picture in so-called loose shoulder

International Nuclear Information System (INIS)

Kuroda, Shigehito; Sakamaki, Hiroshi; Matsuoka, Akira; Moriishi, Takeji; Takada, Keiichi.

1985-01-01

CT picture of the shoulder joint was analyzed in 124 shoulders (114 patients). A line perpendicular to a given line between the precornu of acetabular tegmen (A) and the postcornu of acetabular tegmen (B) was drawn and the intersection where the line and the caput humeri meet (C) was obtained. The angle of CAB was defined as the backward angular aperture of the acetabular tegmen. The angular aperture was 26.2 0 +-1.9 in 16 so-called loose shoulders, 17.3 0 +-1.0 in 28 loose shoulders restricted to the inward rotation, and 12.2 0 +-0.4 in 80 normal shoulders, showing a distinct correlation between the angular aperture and the degree of loose shoulder. An increased backward angular aperture of the acetabular tegmen was considered greatly attributable to the forward glenohumeral movement resulting from malformation of the acetabular tegmen and flaccidity of the joint. Glenoid osteotomy was thus performed in 9 patients, 6 of whom underwent CT scanning before and after osteotomy. Coronal and transverse CT images of the shoulder joint disclosed a noticeable improvement of the glenohumeral alignment. The angular aperture shown on CT seems to be of major importance not only in the diagnosis of so-called loose shoulder but also in surgical choice. (Namekawa, K.)

Dust captures effectiveness of scrubber systems on mechanical miners operating in larger roadways.

CSIR Research Space (South Africa)

Hole, BJ

1998-03-01

Full Text Available The project was directed towards bord and pillar working by mechanised miners operating in larger section roadways, where the problem of scrubber capture tends to be greatest owing to the limited size of the zone of influence around exhaust...

Behavior and Body Patterns of the Larger Pacific Striped Octopus.

Directory of Open Access Journals (Sweden)

Roy L Caldwell

Full Text Available Over thirty years ago anecdotal accounts of the undescribed Larger Pacific Striped Octopus suggested behaviors previously unknown for octopuses. Beak-to-beak mating, dens shared by mating pairs, inking during mating and extended spawning were mentioned in publications, and enticed generations of cephalopod biologists. In 2012-2014 we were able to obtain several live specimens of this species, which remains without a formal description. All of the unique behaviors listed above were observed for animals in aquaria and are discussed here. We describe the behavior, body color patterns, and postures of 24 adults maintained in captivity. Chromatophore patterns of hatchlings are also shown.

Fixation strength analysis of cup to bone material using finite element simulation

NARCIS (Netherlands)

Anwar, Iwan Budiwan; Saputra, Eko; Ismail, Rifky; Jamari, J.; Van Der Heide, Emile

2016-01-01

Fixation of acetabular cup to bone material is an important initial stability for artificial hip joint. In general, the fixation in cement less-type acetabular cup uses press-fit and screw methods. These methods can be applied alone or together. Based on literature survey, the additional screw

Dual mobility cup reduces dislocation rate after arthroplasty for femoral neck fracture

Directory of Open Access Journals (Sweden)

Robertsson Otto

2010-08-01

Full Text Available Abstract Background Hip dislocation after arthroplasty for femoral neck fractures remains a serious complication. The aim of our study was to investigate the dislocation rate in acute femoral neck fracture patients operated with a posterior approach with cemented conventional or dual articulation acetabular components. Methods We compared the dislocation rate in 56 consecutive patients operated with conventional (single mobility cemented acetabular components to that in 42 consecutive patients operated with dual articulation acetabular components. All the patients were operated via posterior approach and were followed up to one year postoperatively. Results There were 8 dislocations in the 56 patients having conventional components as compared to no dislocations in those 42 having dual articulation components (p = 0.01. The groups were similar with respect to age and gender distribution. Conclusions We conclude that the use of a cemented dual articulation acetabular component significantly reduces the dislocation rates in femoral neck fracture patients operated via posterior approach.

Juvenile exposure to predator cues induces a larger egg size in fish

Science.gov (United States)

Segers, Francisca H. I. D.; Taborsky, Barbara

2012-01-01

When females anticipate a hazardous environment for their offspring, they can increase offspring survival by producing larger young. Early environmental experience determines egg size in different animal taxa. We predicted that a higher perceived predation risk by juveniles would cause an increase in the sizes of eggs that they produce as adults. To test this, we exposed juveniles of the mouthbrooding cichlid Eretmodus cyanostictus in a split-brood experiment either to cues of a natural predator or to a control situation. After maturation, females that had been confronted with predators produced heavier eggs, whereas clutch size itself was not affected by the treatment. This effect cannot be explained by a differential female body size because the predator treatment did not influence growth trajectories. The observed increase of egg mass is likely to be adaptive, as heavier eggs gave rise to larger young and in fish, juvenile predation risk drops sharply with increasing body size. This study provides the first evidence that predator cues perceived by females early in life positively affect egg mass, suggesting that these cues allow her to predict the predation risk for her offspring. PMID:21976689

Larger aftershocks happen farther away: nonseparability of magnitude and spatial distributions of aftershocks

Science.gov (United States)

Van Der Elst, Nicholas; Shaw, Bruce E.

2015-01-01

Aftershocks may be driven by stress concentrations left by the main shock rupture or by elastic stress transfer to adjacent fault sections or strands. Aftershocks that occur within the initial rupture may be limited in size, because the scale of the stress concentrations should be smaller than the primary rupture itself. On the other hand, aftershocks that occur on adjacent fault segments outside the primary rupture may have no such size limitation. Here we use high-precision double-difference relocated earthquake catalogs to demonstrate that larger aftershocks occur farther away than smaller aftershocks, when measured from the centroid of early aftershock activity—a proxy for the initial rupture. Aftershocks as large as or larger than the initiating event nucleate almost exclusively in the outer regions of the aftershock zone. This observation is interpreted as a signature of elastic rebound in the earthquake catalog and can be used to improve forecasting of large aftershocks.

Evaluation of a new methodology to simulate damage and wear of polyethylene hip replacements subjected to edge loading in hip simulator testing.

Science.gov (United States)

Partridge, Susan; Tipper, Joanne L; Al-Hajjar, Mazen; Isaac, Graham H; Fisher, John; Williams, Sophie

2018-05-01

Wear and fatigue of polyethylene acetabular cups have been reported to play a role in the failure of total hip replacements. Hip simulator testing under a wide range of clinically relevant loading conditions is important. Edge loading of hip replacements can occur following impingement under extreme activities and can also occur during normal gait, where there is an offset deficiency and/or joint laxity. This study evaluated a hip simulator method that assessed wear and damage in polyethylene acetabular liners that were subjected to edge loading. The liners tested to evaluate the method were a currently manufactured crosslinked polyethylene acetabular liner and an aged conventional polyethylene acetabular liner. The acetabular liners were tested for 5 million standard walking cycles and following this 5 million walking cycles with edge loading. Edge loading conditions represented a separation of the centers of rotation of the femoral head and the acetabular liner during the swing phase, leading to loading of the liner rim on heel strike. Rim damage and cracking was observed in the aged conventional polyethylene liner. Steady-state wear rates assessed gravimetrically were lower under edge loading compared to standard loading. This study supports previous clinical findings that edge loading may cause rim cracking in liners, where component positioning is suboptimal or where material degradation is present. The simulation method developed has the potential to be used in the future to test the effect of aging and different levels of severity of edge loading on a range of cross-linked polyethylene materials. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1456-1462, 2018. © 2017 Wiley Periodicals, Inc.

Larger Bowl Size Increases the Amount of Cereal Children Request, Consume, and Waste

NARCIS (Netherlands)

Wansink, Brian; van Ittersum, Koert; Payne, Collin R.

Objective To examine whether larger bowls bias children toward requesting more food from the adults who serve them. Study design Study 1 was a between-subject design involving 69 preschool-age children who were randomized to receive either a small (8 oz) or large (16 oz) cereal bowl and were asked

Radiology in Gerard uncemented double cup arthroplasty

International Nuclear Information System (INIS)

Willems, W.J.; Rozing, P.M.; Obermann, W.R.

1988-01-01

A radiological follow-up was performed on 109 Gerard (uncemented) double cup arthroplasties, with special emphasis on shift of the femoral cup and protrusion of the acetabular cup, for which a new formula was introduced. Varus shift or axial collapse of the femoral cup played a major role in the failure of these cups. Fluoroscopic examination with video-tape recording seemed to be most helpful in determining abnormalities in this kind of arthroplasty. This examination revealed one normal and two abnormal types of movement, either between both cups or between acetabular cup and acetabular cavity. Those hips with normal movement showed a significantly better clinical score. 16 refs.; 6 figs

The use of allograft bone in reconstruction of the acetabulum during hip revision arthroplasty

International Nuclear Information System (INIS)

David, A.; Morgan, F.; Imran Ilyas

1999-01-01

We have reviewed 80 patients who underwent an allograft acetabular reconstruction between 1987 and 1995. This group had a mean age of 66 years with a mean follow-up of 5.2 years. A mean preoperative Harris hip score of 32 points was improved to a mean postoperative score of 72 points. There was a 16.5% rerevision rate. Acetabular defects were classified according to the American Academy of Orthopaedic Surgeons system. Subgroup classification categories were analysed and reconstruction methodologies have been devised. This paper deals with the relative indications for the use of morsellised bone, block allografts, anatomic specific allografts and reconstruction shells according to type of acetabular defects

Sonographic anatomy of the newborn hip and high-resolution US equipments: internal capsular stripe and perichondral gap

International Nuclear Information System (INIS)

Ortore, P.; Fodor, G.; Psenner, F.; Stuefert, S.; Scherer, M.

1991-01-01

The use of high-resolution US equipments in the examination of the newborn hip allowed the evaluation of a thin echogenic stripe (the internal capsule stripe), which defines laterally the acetabular hyaline cartilage. By means of an anatomo-histological preparation the echogenic stripe can be related to either the capsular circular fibres or the interface between the latter and the hyaline cartilage. The internal capsular stripe, together with the echogenic synovial stripe, precisely delimit the whole acetabular hyaline cartilage. Further-more, in many babies high-resolution US sometimes fails to demonstrate Graft's 'perichondral gap', so that an accurate anatomic knowledge of the hip becomes necessary in the evaluation of acetabular labrum

CT-based quantification of bone stock in large head metal-on-metal unilateral total hip replacements

NARCIS (Netherlands)

Boomsma, Martijn F.; Slouwerhof, Inge; van Lingen, Christiaan; Pakvis, Dean F. M.; van Dalen, Jorn A.; Edens, Mireille A.; Ettema, Harmen B.; Verheyen, Cees C. P. M.; Maas, Mario

2016-01-01

To explore ipsilateral and contralateral acetabular roof bone stock density in unilateral large head MoM THA whether there is a significant lower acetabular bone stock in the hip with a metal-on-metal (MoM) total hip replacement compared to the contralateral side. Second part of this study is to

The JPL functional requirements tool

Science.gov (United States)

Giffin, Geoff; Skinner, Judith; Stoller, Richard

1987-01-01

Planetary spacecraft are complex vehicles which are built according to many thousands of requirements. Problems encountered in documenting and maintaining these requirements led to the current attempt to reduce or eliminate these problems by a computer automated data base Functional Requirements Tool. The tool developed at JPL and in use on several JPL Projects is described. The organization and functionality of the Tool, together with an explanation of the data base inputs, their relationships, and use are presented. Methods of interfacing with external documents, representation of tables and figures, and methods of approval and change processing are discussed. The options available for disseminating information from the Tool are identified. The implementation of the Requirements Tool is outlined, and the operation is summarized. The conclusions drawn from this work is that the Requirements Tool represents a useful addition to the System Engineer's Tool kit, it is not currently available elsewhere, and a clear development path exists to expand the capabilities of the Tool to serve larger and more complex projects.

Protecting the larger fish: an ecological, economical and evolutionary analysis using a demographic model

DEFF Research Database (Denmark)

Verdiell, Nuria Calduch

. Recently, there is increasing evidence that this size-selective fishing reduces the chances of maintaining populations at levels sufficient to produce maximum sustainable yields, the chances of recovery/rebuilding populations that have been depleted/collapsed and may causes rapid evolutionary changes...... and the consequent changes in yield. We attempt to evaluate the capability of the larger fish to mitigate the evolutionary change on life-history traits caused by fishing, while also maintaining a sustainable annual yield. This is achieved by calculating the expected selection response on three life-history traits......Many marine fish stocks are reported as overfished on a global scale. This overfishing not only removes fish biomass, but also causes dramatic changes in the age and size structure of fish stocks. In particular, targeting of the larger individuals truncates the age and size structure of stocks...

The LASS [Larger Aperture Superconducting Solenoid] spectrometer

International Nuclear Information System (INIS)

Aston, D.; Awaji, N.; Barnett, B.

1986-04-01

LASS is the acronym for the Large Aperture Superconducting Solenoid spectrometer which is located in an rf-separated hadron beam at the Stanford Linear Accelerator Center. This spectrometer was constructed in order to perform high statistics studies of multiparticle final states produced in hadron reactions. Such reactions are frequently characterized by events having complicated topologies and/or relatively high particle multiplicity. Their detailed study requires a spectrometer which can provide good resolution in momentum and position over almost the entire solid angle subtended by the production point. In addition, good final state particle identification must be available so that separation of the many kinematically-overlapping final states can be achieved. Precise analyses of the individual reaction channels require high statistics, so that the spectrometer must be capable of high data-taking rates in order that such samples can be acquired in a reasonable running time. Finally, the spectrometer must be complemented by a sophisticated off-line analysis package which efficiently finds tracks, recognizes and fits event topologies and correctly associates the available particle identification information. This, together with complicated programs which perform specific analysis tasks such as partial wave analysis, requires a great deal of software effort allied to a very large computing capacity. This paper describes the construction and performance of the LASS spectrometer, which is an attempt to realize the features just discussed. The configuration of the spectrometer corresponds to the data-taking on K + and K - interactions in hydrogen at 11 GeV/c which took place in 1981 and 1982. This constitutes a major upgrade of the configuration used to acquire lower statistics data on 11 GeV/c K - p interactions during 1977 and 1978, which is also described briefly

The LASS (Larger Aperture Superconducting Solenoid) spectrometer

Energy Technology Data Exchange (ETDEWEB)

Aston, D.; Awaji, N.; Barnett, B.; Bienz, T.; Bierce, R.; Bird, F.; Bird, L.; Blockus, D.; Carnegie, R.K.; Chien, C.Y.

1986-04-01

LASS is the acronym for the Large Aperture Superconducting Solenoid spectrometer which is located in an rf-separated hadron beam at the Stanford Linear Accelerator Center. This spectrometer was constructed in order to perform high statistics studies of multiparticle final states produced in hadron reactions. Such reactions are frequently characterized by events having complicated topologies and/or relatively high particle multiplicity. Their detailed study requires a spectrometer which can provide good resolution in momentum and position over almost the entire solid angle subtended by the production point. In addition, good final state particle identification must be available so that separation of the many kinematically-overlapping final states can be achieved. Precise analyses of the individual reaction channels require high statistics, so that the spectrometer must be capable of high data-taking rates in order that such samples can be acquired in a reasonable running time. Finally, the spectrometer must be complemented by a sophisticated off-line analysis package which efficiently finds tracks, recognizes and fits event topologies and correctly associates the available particle identification information. This, together with complicated programs which perform specific analysis tasks such as partial wave analysis, requires a great deal of software effort allied to a very large computing capacity. This paper describes the construction and performance of the LASS spectrometer, which is an attempt to realize the features just discussed. The configuration of the spectrometer corresponds to the data-taking on K and K interactions in hydrogen at 11 GeV/c which took place in 1981 and 1982. This constitutes a major upgrade of the configuration used to acquire lower statistics data on 11 GeV/c K p interactions during 1977 and 1978, which is also described briefly.

Evaluation of late redislocation in patients who underwent open reduction and pelvic osteotomy as treament for developmental dysplasia of the hip.

Science.gov (United States)

Tuhanioğlu, Ümit; Cicek, Hakan; Ogur, Hasan U; Seyfettinoglu, Firat; Kapukaya, Ahmet

2017-10-16

The goal in the treatment of developmental dysplasia of the hip (DDH) is to achieve a stable and concentric reduction and to create a congruent relationship between the femoral head and the acetabulum. This study discusses the causes of loss of reduction in DDH patients who had a concentrically reduced hip at the time of removal of the hip spica cast and cessation of brace use and who later appeared with hip redislocation after mobilisation and ambulation. In addition, the possible interventions in such cases are also discussed. A retrospective evaluation was made of 13 patients diagnosed with DDH who developed redislocation following primary surgery. 6 of them had undergone the 1st surgery in our department between 2008 and 2016 and 7 had udergone surgery in another centre. For comparison reasons a 2nd group was formed of 13 demographically and clinically matched patients who had no loss of reduction. The groups were compared in terms of acetabular index, pelvic length, pelvic width, abduction degree of plaster, ossifying nucleus diameter, acetabular depth, and acetabular volume parameters. The average age of the patients was 23 months at initial surgery and 29 months at the time of revision surgery. No significant difference was found between the groups in terms of acetabular inclination angle, ossifying nucleus diameter, pelvic size, pelvic width, centre edge angle, acetabular volume, and depth. Contracted inferomedial capsule was found in 1 patient who underwent revision surgery and intact transverse acetabular ligament was seen in 1 patient. The loss of reduction in the remaining 11 patients was associated with high total anteversion of the femoral head and acetabulum. Correction of increased combined anteversion by femoral osteotomy can create a safe zone in terms of redislocation and can significantly contribute to the stability provided by capsulorrhaphy and pelvic osteotomy.

A specialist toxicity database (TRACE) is more effective than its larger, commercially available counterparts

NARCIS (Netherlands)

Anderson, C.A.; Copestake, P.T.; Robinson, L.

2000-01-01

The retrieval precision and recall of a specialist bibliographic toxicity database (TRACE) and a range of widely available bibliographic databases used to identify toxicity papers were compared. The analysis indicated that the larger size and resources of the major bibliographic databases did not,

Design optimization of cementless metal-backed cup prostheses using the concept of functionally graded material

Energy Technology Data Exchange (ETDEWEB)

Hedia, H S; El-Midany, T T; Shabara, M A N; Fouda, N [Production Engineering and M/C Design Department, Faculty of Engineering, Mansoura University, Mansoura (Egypt)

2006-09-15

Metal backing has been widely used in acetabular cup design. A stiff backing for a polyethylene liner was initially believed to be mechanically favourable. Yet, recent studies of the load transfer around acetabular cups have shown that a stiff backing causes two problems. It generates higher stress peaks around the acetabular rim than those caused by full polyethylene cups and reduces the stresses transferred to the dome of the acetabulum causing stress shielding. The aim of this study is to overcome these two problems by improving the design of cementless metal-backed acetabular cups using the two-dimensional functionally graded material (FGM) concept through finite-element analysis and optimization techniques. It is found that the optimal 2D FGM model must have three bioactive materials of hydroxyapatite, Bioglass and collagen. This optimal material reduces the stress shielding at the dome of the acetabulum by 40% and 37% compared with stainless steel and titanium metal backing shells, respectively. In addition, using the 2D FGM model reduces the maximum interface shear stress in the bone by 31% compared to the titanium metal backing shell.

New nonbinary quantum codes with larger distance constructed from BCH codes over 𝔽q2

Science.gov (United States)

Xu, Gen; Li, Ruihu; Fu, Qiang; Ma, Yuena; Guo, Luobin

2017-03-01

This paper concentrates on construction of new nonbinary quantum error-correcting codes (QECCs) from three classes of narrow-sense imprimitive BCH codes over finite field 𝔽q2 (q ≥ 3 is an odd prime power). By a careful analysis on properties of cyclotomic cosets in defining set T of these BCH codes, the improved maximal designed distance of these narrow-sense imprimitive Hermitian dual-containing BCH codes is determined to be much larger than the result given according to Aly et al. [S. A. Aly, A. Klappenecker and P. K. Sarvepalli, IEEE Trans. Inf. Theory 53, 1183 (2007)] for each different code length. Thus families of new nonbinary QECCs are constructed, and the newly obtained QECCs have larger distance than those in previous literature.

Designing key-dependent chaotic S-box with larger key space

International Nuclear Information System (INIS)

Yin Ruming; Yuan Jian; Wang Jian; Shan Xiuming; Wang Xiqin

2009-01-01

The construction of cryptographically strong substitution boxes (S-boxes) is an important concern in designing secure cryptosystems. The key-dependent S-boxes designed using chaotic maps have received increasing attention in recent years. However, the key space of such S-boxes does not seem to be sufficiently large due to the limited parameter range of discretized chaotic maps. In this paper, we propose a new key-dependent S-box based on the iteration of continuous chaotic maps. We explore the continuous-valued state space of chaotic systems, and devise the discrete mapping between the input and the output of the S-box. A key-dependent S-box is constructed with the logistic map in this paper. We show that its key space could be much larger than the current key-dependent chaotic S-boxes.

Larger Neural Responses Produce BOLD Signals That Begin Earlier in Time

Directory of Open Access Journals (Sweden)

Serena eThompson

2014-06-01

Full Text Available Functional MRI analyses commonly rely on the assumption that the temporal dynamics of hemodynamic response functions (HRFs are independent of the amplitude of the neural signals that give rise to them. The validity of this assumption is particularly important for techniques that use fMRI to resolve sub-second timing distinctions between responses, in order to make inferences about the ordering of neural processes. Whether or not the detailed shape of the HRF is independent of neural response amplitude remains an open question, however. We performed experiments in which we measured responses in primary visual cortex (V1 to large, contrast-reversing checkerboards at a range of contrast levels, which should produce varying amounts of neural activity. Ten subjects (ages 22-52 were studied in each of two experiments using 3 Tesla scanners. We used rapid, 250 msec, temporal sampling (repetition time, or TR and both short and long inter-stimulus interval (ISI stimulus presentations. We tested for a systematic relationship between the onset of the HRF and its amplitude across conditions, and found a strong negative correlation between the two measures when stimuli were separated in time (long- and medium-ISI experiments, but not the short-ISI experiment. Thus, stimuli that produce larger neural responses, as indexed by HRF amplitude, also produced HRFs with shorter onsets. The relationship between amplitude and latency was strongest in voxels with lowest mean-normalized variance (i.e., parenchymal voxels. The onset differences observed in the longer-ISI experiments are likely attributable to mechanisms of neurovascular coupling, since they are substantially larger than reported differences in the onset of action potentials in V1 as a function of response amplitude.

Impact of Alternative Inputs and Grooming Methods on Large-R Jet Reconstruction in ATLAS

CERN Document Server

The ATLAS collaboration

2017-01-01

During Run 1 of the LHC, the optimal reconstruction algorithm for large-$R$ jets in ATLAS, characterized in terms of the ability to discriminate signal from background and robust reconstruction in the presence of pileup, was found to be anti-$k_{t}$ jets with a radius parameter of 1.0, formed from locally calibrated topological calorimeter cell clusters and groomed with the trimming algorithm to remove contributions from pileup and underlying event. Since that time, much theoretical, phenomenological, and experimental work has been performed to improve both the reconstruction of the jet inputs as well as the grooming techniques applied to reconstructed jets. In this work, an inclusive survey of both pileup mitigation algorithms applied to calorimeter cell clusters and grooming algorithms is done to study their pileup stability and ability to identify hadronically decaying W bosons within the ATLAS experiment. It is found that compared to the conventional reconstruction algorithm of large-$R$ trimmed jets form...

Emotional event-related potentials are larger to figures than scenes but are similarly reduced by inattention

Directory of Open Access Journals (Sweden)

Nordström Henrik

2012-05-01

Full Text Available Abstract Background In research on event-related potentials (ERP to emotional pictures, greater attention to emotional than neutral stimuli (i.e., motivated attention is commonly indexed by two difference waves between emotional and neutral stimuli: the early posterior negativity (EPN and the late positive potential (LPP. Evidence suggests that if attention is directed away from the pictures, then the emotional effects on EPN and LPP are eliminated. However, a few studies have found residual, emotional effects on EPN and LPP. In these studies, pictures were shown at fixation, and picture composition was that of simple figures rather than that of complex scenes. Because figures elicit larger LPP than do scenes, figures might capture and hold attention more strongly than do scenes. Here, we showed negative and neutral pictures of figures and scenes and tested first, whether emotional effects are larger to figures than scenes for both EPN and LPP, and second, whether emotional effects on EPN and LPP are reduced less for unattended figures than scenes. Results Emotional effects on EPN and LPP were larger for figures than scenes. When pictures were unattended, emotional effects on EPN increased for scenes but tended to decrease for figures, whereas emotional effects on LPP decreased similarly for figures and scenes. Conclusions Emotional effects on EPN and LPP were larger for figures than scenes, but these effects did not resist manipulations of attention more strongly for figures than scenes. These findings imply that the emotional content captures attention more strongly for figures than scenes, but that the emotional content does not hold attention more strongly for figures than scenes.

Emotional event-related potentials are larger to figures than scenes but are similarly reduced by inattention

Science.gov (United States)

2012-01-01

Background In research on event-related potentials (ERP) to emotional pictures, greater attention to emotional than neutral stimuli (i.e., motivated attention) is commonly indexed by two difference waves between emotional and neutral stimuli: the early posterior negativity (EPN) and the late positive potential (LPP). Evidence suggests that if attention is directed away from the pictures, then the emotional effects on EPN and LPP are eliminated. However, a few studies have found residual, emotional effects on EPN and LPP. In these studies, pictures were shown at fixation, and picture composition was that of simple figures rather than that of complex scenes. Because figures elicit larger LPP than do scenes, figures might capture and hold attention more strongly than do scenes. Here, we showed negative and neutral pictures of figures and scenes and tested first, whether emotional effects are larger to figures than scenes for both EPN and LPP, and second, whether emotional effects on EPN and LPP are reduced less for unattended figures than scenes. Results Emotional effects on EPN and LPP were larger for figures than scenes. When pictures were unattended, emotional effects on EPN increased for scenes but tended to decrease for figures, whereas emotional effects on LPP decreased similarly for figures and scenes. Conclusions Emotional effects on EPN and LPP were larger for figures than scenes, but these effects did not resist manipulations of attention more strongly for figures than scenes. These findings imply that the emotional content captures attention more strongly for figures than scenes, but that the emotional content does not hold attention more strongly for figures than scenes. PMID:22607397

Examples of fatigue lifetime and reliability evaluation of larger wind turbine components

DEFF Research Database (Denmark)

Tarp-Johansen, N.J.

2003-01-01

This report is one out of several that constitute the final report on the ELSAM funded PSO project “Vindmøllekomponenters udmattelsesstyrke og levetid”, project no. 2079, which regards the lifetime distribution of larger wind turbine components in ageneric turbine that has real life dimensions....... Though it was the initial intention of the project to consider only the distribution of lifetimes the work reported in this document provides also calculations of reliabilities and partial load safetyfactors under specific assumptions about uncertainty sources, as reliabilities are considered...

Burdigalian turbid water patch reef environment revealed by larger benthic foraminifera

Science.gov (United States)

Novak, V.; Renema, W.; Throughflow-project

2012-04-01

Ancient isolated patch reefs outcropping from siliciclastic sediments are a trademark for the Miocene carbonate deposits occurring in East Kalimantan, Indonesia. They develop in transitional shelf sediments deposited between deltaic and deep marine deposits (Allen and Chambers, 1998). The Batu Putih Limestone (Wilson, 2005) and similar outcrops in adjacent areas have been characterized as shallow water carbonates influenced by high siliciclastic input, showing low relief patch reefs in turbid waters. Larger benthic foraminifera (LBF) are excellent markers for biochronology and paleoenvironmental reconstruction. This study aims to reveal age and paleoenvironment of a shallow water carbonate patch reef developed in mixed depositional system by using LBF and microfacies analysis. The studied section is located near Bontang, East Kalimantan, and is approximately 80 m long and 12 m high. It is placed within Miocene sediments in the central part of the Kutai Basin. Patch reef and capping sediments were logged through eight transects along section and divided into nine different lithological units from which samples were collected. Thin sections and isolated specimens of larger benthic foraminifera were analyzed and recognized to species level (where possible) providing age and environmental information. Microfacies analysis of thin sections included carbonate classification (textural scheme of Dunham, 1962) and assemblage composition of LBF, algae and corals relative abundance. Three environmentally indicative groups of LBF were separated based on test morphology, habitat or living relatives (Hallock and Glenn, 1986). Analysed foraminifera assemblage suggests Burdigalian age (Tf1). With use of microfacies analysis nine successive lithological units were grouped into five facies types. Paleoenvironmental reconstruction of LBF fossil assemblage indicate two cycles of possible deepening recorded in the section. Based on high muddy matrix ratio in analyzed thin-sections we

Magnetic nanoparticles formed in glasses co-doped with iron and larger radius elements

OpenAIRE

Edelman , Irina; Ivanova , Oxana; Ivantsov , Ruslan; Velikanov , D.; Zabluda , V.; Zubavichus , Y.; Veligzhanin , A.; Zaikovskiy , V.; Stepanov , S.; Artemenko , Alla; Curély , Jacques; Kliava , Janis

2012-01-01

International audience; A new type of nanoparticle-containing glasses based on borate glasses co-doped with low contents of iron and larger radius elements, Dy, Tb, Gd, Ho, Er, Y, and Bi, is studied. Heat treatment of these glasses results in formation of magnetic nanoparticles, radically changing their physical properties. Transmission electron microscopy and synchrotron radiation-based techniques: x-ray diffraction, extended x-ray absorption fine structure, x-ray absorption near-edge struct...

Efficiency and Reliability of Laparoscopic Partial Nephrectomy for Renal Tumors Larger than 4 cm

Directory of Open Access Journals (Sweden)

Faruk Özgör

2015-03-01

Full Text Available Aim: To evaluate safety and efficiency of laparoscopic partial nephrectomy for renal tumors larger than 4 cm. Methods: We retrospectivelly evaluated the medical records of 65 patients who underwent laparascopic partial nephrectomy between May 2009 and June 2013 in our clinic. The patients were divided into two groups according to tumor size. Patients with a tumor 4 cm were included in group 1 (n=45 and group 2 (n=20, respectively. Demographic, perioperative and postoperative parameters were compared between the groups. Histopathological examination and surgical margin status were also evaluated. Results: The mean age of the patients was 59.2±10.9 (range: 26- 81 years. The mean tumor size and the mean RENAL nephrometry score were significantly higher in group 2 than in group 1. The mean operation time and warm ischemia time were similar between groups but estimated blood loss and transfusion requirement were significantly higher in group 2. Convertion to open surgery was seen two patients in group 2 and one patient in group 1. Only one patient underwent radical nephrectomy for uncontrolled bleeding in group 2. There was no difference in preoperative and 3-month postoperative serum creatinine levels between the groups. The incidence of positive surgical margin was 0% and 5% in group 1 and group 2, respectively. Conclusion: Laparoscopic partial nephrectomy for renal tumors is an effective and feasible procedure with acceptable oncologic results. However, tranfusion rate and requiremet of pelvicaliceal system repair were more common in patients with tumor >4 cm. (The Medical Bulletin of Haseki 2015; 53:30-5

Ventilation efficiency in a low-energy dwelling setting – a parameter study for larger rooms

NARCIS (Netherlands)

Dijkstra, D.; Loomans, M.G.L.C.; Hensen, J.L.M.; Cremers, B.E. (Bart)

2016-01-01

Mechanical balanced ventilation systems typically is applied in new and renovated dwellings in The Netherlands. The application assumes an adequate ventilation efficiency but this has not been confirmed for larger rooms (e.g. living rooms with kitchen attached). This study investigates ventilation

When larger brains do not have more neurons: Increased numbers of cells are compensated by decreased average cell size across mouse individuals

Directory of Open Access Journals (Sweden)

Suzana eHerculano-Houzel

2015-06-01

Full Text Available There is a strong trend toward increased brain size in mammalian evolution, with larger brains composed of more and larger neurons than smaller brains across species within each mammalian order. Does the evolution of increased numbers of brain neurons, and thus larger brain size, occur simply through the selection of individuals with more and larger neurons, and thus larger brains, within a population? That is, do individuals with larger brains also have more, and larger, neurons than individuals with smaller brains, such that allometric relationships across species are simply an extension of intraspecific scaling? Here we show that this is not the case across adult male mice of a similar age. Rather, increased numbers of neurons across individuals are accompanied by increased numbers of other cells and smaller average cell size of both types, in a trade-off that explains how increased brain mass does not necessarily ensue. Fundamental regulatory mechanisms thus must exist that tie numbers of neurons to numbers of other cells and to average cell size within individual brains. Finally, our results indicate that changes in brain size in evolution are not an extension of individual variation in numbers of neurons, but rather occur through step changes that must simultaneously increase numbers of neurons and cause cell size to increase, rather than decrease.

Relationships among measurements obtained by use of computed tomography and radiography and scores of cartilage microdamage in hip joints with moderate to severe joint laxity of adult dogs.

Science.gov (United States)

Lopez, Mandi J; Lewis, Brooke P; Swaab, Megan E; Markel, Mark D

2008-03-01

To evaluate correlations among measurements on radiographic and computed tomography (CT) images with articular cartilage microdamage in lax hip joints of dogs. 12 adult mixed-breed hounds. Pelvic CT and radiography were performed. Hip joints were harvested following euthanasia. Orthopedic Foundation for Animals (OFA) and PennHIP radiograph reports were obtained. Norberg angle (NA) and radiographic percentage femoral head coverage (RPC) were determined. Center-edge angle (CEA), horizontal toit externe angle (HTEA), ventral acetabular sector angle (VASA), dorsal acetabular sector angle (DASA), horizontal acetabular sector angle (HASA), acetabular index (AI), and CT percentage femoral head coverage (CPC) were measured on 2-dimensional CT images. Femoral head-acetabular shelf percentage was measured on sagittal 3-dimensional CT (SCT) and transverse 3-dimensional CT (TCT) images. Light microscopy was used to score joint cartilage. Relationships of OFA confirmation and PennHIP osteoarthritis scores with radiography, CT, and cartilage variables and relationships of cartilage scores with radiography and CT measurements were evaluated with Spearman rank correlations. Pearson correlation was used for relationships of distraction index (DI) with radiography, CT, and cartilage variables. Significant relationships included PennHIP osteoarthritis score with cartilage score, CEA, HTEA, DASA, AI, CPC, and TCT; OFA confirmation score with cartilage score, NA, RPC, CEA, HTEA, DASA, AI, CPC, and TCT; cartilage score with NA, RPC, CEA, HTEA, DASA, HASA, AI, and TCT; and DI with cartilage score, CEA, HTEA, DASA, HASA, AI, and CPC. CT appeared to be a valuable imaging modality for predicting cartilage microdamage in canine hip joints.

Hip morphology predicts posterior hip impingement in a cadaveric model.

Science.gov (United States)

Morris, William Z; Fowers, Cody A; Weinberg, Douglas S; Millis, Michael B; Tu, Leigh-Anne; Liu, Raymond W

2018-05-01

Posterior hip impingement is a recently-identified cause of hip pain. The purpose of this study is to characterise posterior femoroacetabular and ischiofemoral impingement and identify its predisposing morphologic traits. Two hundred and six cadaveric hips were randomly selected and taken through controlled motion in two pure axes associated with posterior hip impingement: external rotation (through the mechanical axis) and adduction (coronal plane). The range of motion and location of impingement was noted for each specimen. Morphologic traits including femoral/acetabular version, and true neck-shaft angle (TNSA) were also measured. External rotation impingement occurred between the femoral neck and acetabulum in 83.0% of hips, and between the lesser trochanter and ischial tuberosity in 17.0%. Adduction impingement occurred between the lesser trochanter and ischial tuberosity in 78.6% of hips, and between the femoral neck and acetabulum in 21.4%. Multiple regression revealed that increased femoral/acetabular version predicted earlier external rotation and adduction impingement. Unstandardised betas ranging from -0.39 to -0.64 reflect that each degree of increased femoral/acetabular version individually accounts for a loss of external rotation or adduction of approximately half a degree before impingement ( p < 0.001 for each). Increased TNSA was associated with earlier adduction impingement only (unstandardised beta -0.35, p = 0.005). Relative femoral/acetabular anteversion was associated with earlier posterior hip impingement. Coxa valga was associated with earlier adduction impingement, but protective against external rotation impingement. These findings highlight the importance of monitoring correction during femoral/acetabular osteotomies, as overcorrection of retroversion may predispose to earlier posterior impingement.

[Prophylactic osteotomy of pelvis in dysplastic acetabulum.].

Science.gov (United States)

Richtr, M; Sosna, A

1998-01-01

Acetabular dysplasia and anatomical changes of pelvis accompanied with gracility of iliac bone pose a problem for a reliable fixation of acetabular component. In extreme cases the bone stock is not sufficient to accommodate the smallest size of the cup. Sometimes even reaming of the bed down to lamina interna is not sufficient for an adequate covering of the implant. Consequently, weakening of the bottom of acetabulum may be not only one of the causes of the failure of the implant but it makes difficult also the following revision surgeries. Therefore in acetabular dysplasia the authors recommend acetabuloplasty of the bottom of acetabulum preserving its original thickness including inner cortex. They recommend to perform osteotomy of the full thickness of the medial wall of acetabulum and move the massive bone graft created in this way farther into pelvis. At the same time they take care to preserve blood supply of the bone graft by retaining corticoperiostal bridge by means of osteoclasia. The suggested procedure allows full coverage of the implant by iliac bone and at the same time preserves a firm support of acetabular fossa. The original thickness of the medial wall of acetabulum is considered by authors as a significant antimigration barrier. In the period 1991 -1994 the authors used this method at Ist Orthopaedic Clinic of 1st Medical Faculty, Charles University in Prague in total in 16 patients. In all of them after 6 months the bone graft was fully absorbed. Remodelling of the bone graft occurred 1 to 2 years after the surgery and after that the thickness of the graft remained the same. Neither any change of the structure nor reduction of the thickness of the graft was found between 3rd and 4th year after the surgery. The nature of trabecular remodelling of the bone graft corresponds to the transfer of forces in loading the graft by acetabular cup. Key words: acetabuloplasty, osteotomy of the medial wall of acetabulum, osteotomy of pelvis, THR, acetabular

Larger red-shift in optical emissions obtained from the thin films of globular proteins (BSA, lysozyme) – polyelectrolyte (PAA) complexes

Energy Technology Data Exchange (ETDEWEB)

Talukdar, Hrishikesh [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Vigyan Path, Paschim Boragaon, Garchuk, Guwahati 781035, Assam (India); Kundu, Sarathi, E-mail: sarathi.kundu@gmail.com [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Vigyan Path, Paschim Boragaon, Garchuk, Guwahati 781035, Assam (India); Basu, Saibal [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2016-09-30

Graphical abstract: Thin films of protein-polyelectrolyte complexes show larger red-shift in optical emission. - Highlights: • Globular proteins (lysozyme and BSA) and polyelectrolyte (sodium polyacrylic acid) are used to form protein-polyelectrolyte complexes (PPC). • Larger red-shift in optical emission is obtained from the thin films of PPC. • Red-shift is not obtained from the solution of PPC and pure protein thin films. • Larger red-shift from PPC films is due to the energy dissipation as non-radiative form through interactions with nearby atoms. • Red-shift in optical emission is independent on the thickness of the PPC film. - Abstract: Globular proteins (lysozyme and BSA) and polyelectrolyte (sodium polyacrylic acid) are used to form protein-polyelectrolyte complexes (PPC). Out-of-plane structures of ≈30–60 nm thick PPC films and their surface morphologies have been studied by using X-ray reflectivity and atomic force microscopy, whereas optical behaviors of PPC and protein conformations have been studied by using UV–vis, photoluminescence and FTIR spectroscopy respectively. Our study reveals that thin films of PPC show a larger red-shift of 23 and 16 nm in the optical emissions in comparison to that of pure protein whereas bulk PPC show a small blue-shift of ≈3 nm. A small amount of peak-shift is found to occur due to the heat treatment or concentration variation of the polyelectrolyte/protein in bulk solution but cannot produce such film thickness independent larger red-shift. Position of the emission peak remains nearly unchanged with the film thickness. Mechanism for such larger red-shift has been proposed.

Diagnosis of lesions of the acetabular labrum, of the labral-chondral transition zone, and of the cartilage in femoroacetabular impingement: Correlation between direct magnetic resonance arthrography and hip arthroscopy.

Science.gov (United States)

Crespo Rodríguez, A M; de Lucas Villarrubia, J C; Pastrana Ledesma, M A; Millán Santos, I; Padrón, M

2015-01-01

To determine the sensitivity and accuracy of direct MR arthrography in the diagnosis of intra-articular lesions associated with femoroacetabular impingement. We used direct MR arthrography to study 51 patients with femoroacetabular impingement who underwent arthroscopic hip surgery. Surgery demonstrated 37 labral tears, 44 lesions in the labral-chondral transitional zone, and 40 lesions of the articular cartilage. We correlated the findings at preoperative direct MR arthrography with those of hip arthroscopy and calculated the sensitivity, specificity, positive predictive value, negative predictive value, and validity index for direct MR arthrography. The sensitivity and specificity of MR arthrography were 94.5% and 100%, respectively, for diagnosing labral tears, 100% and 87.5%, respectively, for diagnosing lesions of the labral-chondral transition zone, and 92.5% and 54.5%, respectively, for diagnosing lesions of the articular cartilage. The negative predictive value of MR arthrography for lesions of the labral-chondral transitional zone was 100%. MR arthrography accurately defined extensive lesions of the cartilage and the secondary osseous changes (the main factor in poor prognosis), although its diagnostic performance was not so good in small chondral lesions. In patients with femoroacetabular impingement, direct MR arthrography can adequately detect and characterize lesions of the acetabular labrum and of the labral-chondral transitional zone as well as extensive lesions of the articular cartilage and secondary osseous changes. Copyright © 2013 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

Fuel requirements for experimental devices in MTR reactors. A perturbation model for reactor core analysis

International Nuclear Information System (INIS)

Beeckmans de West-Meerbeeck, A.

1991-01-01

Irradiation in neutron absorbing devices, requiring high fast neutron fluxes in the core or high thermal fluxes in the reflector and flux traps, lead to higher density fuel and larger core dimensions. A perturbation model of the reactor core helps to estimate the fuel requirements. (orig.)

Treatment Algorithm for Patients with Non-arthritic Hip Pain, Suspect for an Intraarticular Pathology

DEFF Research Database (Denmark)

Jørgensen, Rasmus Wejnold; Dippmann, Christian; Dahl, L

2016-01-01

BACKGROUND: The amount of patients referred with longstanding, non-arthritic hip pain is increasing, as are the treatment options. Left untreated hip dysplasia, acetabular retroversion and femoroacetabular impingement (FAI) may lead to osteoarthritis (OA). Finding the right treatment option...... associated with acetabular retroversion described in the literature were the crossover sign, the posterior wall sign and the ischial spine sign, while Wiberg's lateral center-edge angle (CE-angle) together with Leqeusne's acetabular index indicate hip dysplasia. A Tönnis index >2 indicates osteoarthritis...... for the right patient can be challenging in patients with non-arthritic hip pain. PURPOSE: The purpose of this study was to categorize the radiographic findings seen in patients with longstanding hip pain, suspect for an intraarticular pathology, and provide a treatment algorithm allocating a specific treatment...

Application of Rapid Prototyping Pelvic Model for Patients with DDH to Facilitate Arthroplasty Planning: A Pilot Study.

Science.gov (United States)

Xu, Jie; Li, Deng; Ma, Ruo-fan; Barden, Bertram; Ding, Yue

2015-11-01

Total hip arthroplasty (THA) is challenging in cases of osteoarthritis secondary to developmental dysplasia of the hip (DDH). Acetabular deficiency makes the positioning of the acetabular component difficult. Computer tomography based, patient-individual three dimensional (3-D) rapid prototype technology (RPT)-models were used to plan the placement of acetabular cup so that a surgeon was able to identify pelvic structures, assess the ideal extent of reaming and determine the size of cup after a reconstructive procedure. Intraclass correlation coefficients (ICCs) were used to analyze the agreement between the sizes of chosen components on the basis of preoperative planning and the actual sizes used in the operation. The use of the 3-D RPT-model facilitates the surgical procedures due to better planning and improved orientation. Copyright © 2015 Elsevier Inc. All rights reserved.

An improved permanent magnet quadrupole design with larger good field region for high intensity proton linacs

Energy Technology Data Exchange (ETDEWEB)

Mathew, Jose V., E-mail: josev.mathew@gmail.com; Rao, S.V.L.S.; Krishnagopal, S.; Singh, P.

2013-11-01

The Low Energy High Intensity Proton Accelerator (LEHIPA), being developed at the Bhabha Atomic Research Centre (BARC) will produce a 20 MeV, 30 mA, continuous wave (CW) proton beam. At these low velocities, space-charge forces dominate, and could lead to larger beam sizes and beam halos. Hence in the design of the focusing lattice of the LEHIPA drift tube linac (DTL) using permanent magnet quadrupoles (PMQs), a larger good field region is preferred. Here we study, using the two dimensional (2D) and three dimensional (3D) simulation codes PANDIRA and RADIA, four different types of cylindrical PMQ designs: 16-segment trapezoidal Halbach configuration, bullet-nosed geometry and 8- and 16-segment rectangular geometries. The trapezoidal Halbach geometry is used in a variety of accelerators since it provides very high field gradients in small bores, while the bullet-nosed geometry, which is a combination of the trapezoidal and rectangular designs, is used in some DTLs. This study shows that a larger good field region is possible in the 16-segment rectangular design as compared to the Halbach and bullet-nosed designs, making it more attractive for high-intensity proton linacs. An improvement in good-field region by ∼16% over the Halbach design is obtained in the optimized 16-segment rectangular design, although the field gradient is lower by ∼20%. Tolerance studies show that the rectangular segment PMQ design is substantially less sensitive to the easy axis orientation errors and hence will be a better choice for DTLs. -- Highlights: • An improved permanent magnet quadrupole (PMQ) design with larger good field region is proposed. • We investigate four PMQ designs, including the widely used Halbach and bullet nosed designs. • Analytical calculations are backed by 2D as well as 3D numerical solvers, PANDIRA and RADIA. • The optimized 16 segment rectangular PMQ design is identified to exhibit the largest good field region. • The effect of easy axis orientation

An improved permanent magnet quadrupole design with larger good field region for high intensity proton linacs

International Nuclear Information System (INIS)

Mathew, Jose V.; Rao, S.V.L.S.; Krishnagopal, S.; Singh, P.

2013-01-01

The Low Energy High Intensity Proton Accelerator (LEHIPA), being developed at the Bhabha Atomic Research Centre (BARC) will produce a 20 MeV, 30 mA, continuous wave (CW) proton beam. At these low velocities, space-charge forces dominate, and could lead to larger beam sizes and beam halos. Hence in the design of the focusing lattice of the LEHIPA drift tube linac (DTL) using permanent magnet quadrupoles (PMQs), a larger good field region is preferred. Here we study, using the two dimensional (2D) and three dimensional (3D) simulation codes PANDIRA and RADIA, four different types of cylindrical PMQ designs: 16-segment trapezoidal Halbach configuration, bullet-nosed geometry and 8- and 16-segment rectangular geometries. The trapezoidal Halbach geometry is used in a variety of accelerators since it provides very high field gradients in small bores, while the bullet-nosed geometry, which is a combination of the trapezoidal and rectangular designs, is used in some DTLs. This study shows that a larger good field region is possible in the 16-segment rectangular design as compared to the Halbach and bullet-nosed designs, making it more attractive for high-intensity proton linacs. An improvement in good-field region by ∼16% over the Halbach design is obtained in the optimized 16-segment rectangular design, although the field gradient is lower by ∼20%. Tolerance studies show that the rectangular segment PMQ design is substantially less sensitive to the easy axis orientation errors and hence will be a better choice for DTLs. -- Highlights: • An improved permanent magnet quadrupole (PMQ) design with larger good field region is proposed. • We investigate four PMQ designs, including the widely used Halbach and bullet nosed designs. • Analytical calculations are backed by 2D as well as 3D numerical solvers, PANDIRA and RADIA. • The optimized 16 segment rectangular PMQ design is identified to exhibit the largest good field region. • The effect of easy axis orientation

The cause of larger local magnitude (Mj) in western Japan

Science.gov (United States)

Kawamoto, H.; Furumura, T.

2017-12-01

The local magnitude of the Japan Meteorological Agency (JMA) scale (Mj) in Japan sometimes show a significant discrepancy between Mw. The Mj is calculated using the amplitude of the horizontal component of ground displacement recorded by seismometers with the natural period of T0=5 s using Katsumata et al. (2004). A typical example of such a discrepancy in estimating Mj was an overestimation of the 2000 Western Tottori earthquake (Mj=7.3, Mw=6.7; hereafter referred to as event T). In this study, we examined the discrepancy between Mj and Mw for recent large earthquakes occurring in Japan.We found that the most earthquakes with larger Mj (>Mw) occur in western Japan while the earthquakes in northern Japan show reasonable Mj (=Mw). To understand the cause of such larger Mj for western Japan earthquakes we examined the strong motion record from the K-NET and KiK-net network for the event T and other earthquakes for reference. The observed ground displacement record from the event T shows a distinctive Love wave packet in tangential motion with a dominant period of about T=5 s which propagates long distances without showing strong dispersions. On the other hand, the ground motions from the earthquakes in northeastern Japan do not have such surface wave packet, and attenuation of ground motion is significant. Therefore, the overestimation of the Mj for earthquakes in western Japan may be attributed to efficient generation and propagation properties of Love wave probably relating to the crustal structure of western Japan. To explain this, we then conducted a numerical simulation of seismic wave propagation using 3D sedimentary layer model (JIVSM; Koketsu et al., 2012) and the source model of the event T. The result demonstrated the efficient generation of Love wave from the shallow strike-slip source which propagates long distances in western Japan without significant dispersions. On the other hand, the generation of surface wave was not so efficient when using a

The erection of larger windmills in the open countryside - an investigation of the visual effects

International Nuclear Information System (INIS)

1996-12-01

The future use of larger windmills will result in new visual effects. The investigation points out that these effects will be dependent on the main characteristics of the landscape. Windmills with a height of 90 m will be taller than any other element found in the landscape with the exception of some chimneys, masts, etc. It is shown that very tall windmills should not be set up in large dominating groups, that it is important that the towers are slender and that the blades rotate slowly (in order to give a more peaceful effect), if the landscape should not be spoiled. Large windmills dominate an area of 1 - 3 kilometers, but at a distance of 10 - 12 km they can appear to fade away between woods and large buildings etc. Naturally, large windmills will be prominent on heaths and moors, and would not be welcome where there are buildings of cultural interest or where the landscape is under conservation. They could, it is stated, be placed amongst a group of smaller windmills, as this would help to lessen their dominance, but should not be positioned where one type of landscape merges into another, as here they would show up more. Local boundaries should also be taken into consideration. When planning where to locate windmills the overall visual effect over larger areas should be contemplated in addition to the preservation of views of buildings etc. of historical interest. Photographs should be taken of proposed sites so that paper models can be placed so as to produce an idea of the visual effects of erecting larger windmills in various positions in specified areas

On Early Conflict Identification by Requirements Modeling of Energy System Control Structures

DEFF Research Database (Denmark)

Heussen, Kai; Gehrke, Oliver; Niemann, Hans Henrik

2015-01-01

issues early. For requirements formulation of control structures, cyber and physical aspects need to be jointly represented to express interdependencies, check for consistency and discover potentially conflicting requirements. Early identification of potential conflicts may prevent larger problems...... at later design stages. However, languages employed for requirements modeling today do not offer the expressiveness necessary to represent control purposes in relation to domain level interactions and therefore miss several types of interdependencies. This paper introduces the idea of control structure...... modeling for early requirements checking using a suitable modeling language, and illustrates how this approach enables the identification of several classes of controller conflict....

Purchasing innovations in the construction sector in the Netherlands : a comparison between SMEs and larger companies

NARCIS (Netherlands)

de Rijk, Melissa

2015-01-01

Posterpresentatie Ondernemerschapsmiddag KCO, gehouden op 16 november 2015. Main research question: To what extend does the purchasing activity of incremental and radical innovations of SMEs differ from that of larger companies in the construction sector in the Netherlands?

Facilitating control in growing organizations : A study of new requirements on systematization

OpenAIRE

Flyman, Elin; Nilsson, Christina

2013-01-01

Organizational growth poses new challenges for top management. In small organizations, coordination and communication is spontaneous and require little structure to be efficient. However, as the organization grows, the increased number of individuals requires a larger amount of coordination and communication. In this study, our purpose is to increase understanding of why growing companies are experiencing challenges with coordination as well as to increase organizational control. To fulfill t...

Larger bases and mixed analog/digital neural nets

Energy Technology Data Exchange (ETDEWEB)

Beiu, V.

1998-12-31

The paper overviews results dealing with the approximation capabilities of neural networks, and bounds on the size of threshold gate circuits. Based on an explicit numerical algorithm for Kolmogorov`s superpositions the authors show that minimum size neural networks--for implementing any Boolean function--have the identity function as the activation function. Conclusions and several comments on the required precision are ending the paper.

Measuring acetabular cup orientation on antero-posterior radiographs of the hip after total hip arthroplasty with a vector arithmetic radiological method. Is it valid and verified for daily clinical practice?

Energy Technology Data Exchange (ETDEWEB)

Craiovan, B.; Weber, M.; Worlicek, M.; Schneider, M.; Springorum, H.R.; Grifka, J.; Renkawitz, T. [University Medical Center Regensburg, Bad Abbach/Regensburg (Germany). Orthopedic Surgery; Zeman, F. [University Medical Center Regensburg, Bad Abbach/Regensburg (Germany). Center for Clinical Studies

2016-06-15

The aim of this prospective study is to validate a vector arithmetic method for measuring acetabular cup orientation after total hip arthroplasty (THA) and to verify the clinical practice. We measured cup anteversion and inclination of 123 patients after cementless primary THA twice by two examiners on AP pelvic radiographs with a vector arithmetic method and compared with a 3D-CT based reconstruction model within the same radiographic coronal plane. The mean difference between the radiographic and the 3D-CT measurements was -1.4 ±3.9 for inclination and 0.8 ±7.9 for anteversion with excellent correlation for inclination (r=0.81, p < 0.001) and moderate correlation for anteversion (r=0.65, p < 0.001). The intraclass correlation coefficient for measurements on radiographs ranged from 0.98 (95%-CI: 0.98; 0.99) for the first observer to 0.94 (95%-CI: 0.92; 0.96) for the second observer. The interrater reliability was 0.96 (95%-CI: 0.93; 0.98) for inclination and 0.93 (95%-CI: 0.85; 0.96) for anteversion. The largest errors in measurements were associated with an extraordinary pelvic tilt. In order to get a valuable measurement for measuring cup position after THA on pelvic radiographs by this vector arithmetic method, there is a need for a correct postoperative ap view, with special regards to the pelvic tilt for the future.

Center edge angle measurement for hip preservation surgery: technique and caveats.

Science.gov (United States)

Anderson, Lucas A; Gililland, Jeremy; Pelt, Christopher; Linford, Samuel; Stoddard, Gregory J; Peters, Christopher L

2011-01-01

Anterior and lateral center edge angles have traditionally been used to determine acetabular coverage, and thereby strongly influence the decision to perform acetabular reorientation versus osteochondroplasty in patients with dysplasia and/or femoroacetabular impingement. We propose templating the center of the contained articular femoral head in aspherical hips to provide reliable assessment of acetabular coverage. Digital radiographs of 30 patients with various combinations of femoral and acetabular morphologies were evaluated using 2 methods to identify the anterior center edge angle and lateral center edge angle. The control method used an estimated femoral head center for angle apex. The study technique determined the center of the femoral head by templating the congruent aspect of the femoral head contained by the acetabulum while ignoring the increasing lateral and anterior radius associated with cam deformities. Four readers measured lateral center edge angles on anteroposterior radiographs and anterior center edge angles on false-profile radiographs. Two reads were performed by each reader using both the estimated and the templated methods for a total of 4 reads. Interobserver reliability using the proposed method compared to the standard was much improved for anterior center edge angles (intraclass correlation coefficient of 0.76 vs 0.55) as well as with lateral center edge angles (ICC of 0.80 vs 0.42). Decreased correlation was most commonly associated with abnormal sourcil morphology, posterior wall deficiency combined with calcified labra, and os acetabuli. Including the anterolateral cam deformity in identifying the center of the femoral head for measuring center edge angles leads to an underestimation of acetabular coverage, which may negatively affect hip preservation surgical decision making. Copyright 2011, SLACK Incorporated.

AMTD: update of engineering specifications derived from science requirements for future UVOIR space telescopes

Science.gov (United States)

Stahl, H. Philip; Postman, Marc; Mosier, Gary; Smith, W. Scott; Blaurock, Carl; Ha, Kong; Stark, Christopher C.

2014-08-01

The Advance Mirror Technology Development (AMTD) project is in Phase 2 of a multiyear effort, initiated in FY12, to mature by at least a half TRL step six critical technologies required to enable 4 meter or larger UVOIR space telescope primary mirror assemblies for both general astrophysics and ultra-high contrast observations of exoplanets. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND provide a high-performance low-cost low-risk system. To give the science community options, we are pursuing multiple technology paths. A key task is deriving engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicles and their mass and volume constraints. A key finding of this effort is that the science requires an 8 meter or larger aperture telescope.

EOCENE LARGER FORAMINIFERAL BIOSTRATIGRAPHY IN THE SOUTHERNMOST DAUPHINOIS DOMAIN (MARITIME ALPS, FRANCE-ITALY BORDER

Directory of Open Access Journals (Sweden)

DARIO VARRONE

2007-07-01

Full Text Available The Trucco Formation and the Nummulitic Limestone (Dauphinois Domain, Maritime Alps are characterized by abundant larger foraminifera, specifically nummulitids, orthophragminids and encrusting foraminifera. In the Maritime Alps, previous studies suggest a late Lutetian age for the Trucco Formation and a late Lutetian-Priabonian age for the Nummulitic Limestone.Biostratigraphic analysis of the nummulitids, in 11 stratigraphic sections, allowed us to distinguish 3 biozones:MALF1 Zone: defined by the presence of Nummulites brongniarti d’Archiac & Haime, N. puschi d’Archiac, N. perforatus de Montfort, N. striatus (Bruguière, N. cf. dufrenoyi d’Archiac & Haime, N. variolarius/incrassatus and Operculina schwageri Silvestri.MALF2 Zone: defined by the presence of Nummulites perforatus de Montfort, N. striatus (Bruguière, N. cf. dufrenoyi d’Archiac & Haime, N. variolarius/incrassatus and Operculina schwageri Silvestri.MALF 3 Zone: defined by the presence of gr. Nummulites variolarius/incrassatus, N. striatus (Bruguière and Operculina schwageri Silvestri.According to current larger foraminiferal biozonal schemes, the age of these local biozones corresponds to the Bartonian p.p.Moreover, the comparison with biostratigraphic schemes established for the Dauphinois Domain and for the Tethyan area evidences that several typical nummulitid species of the late Bartonian are lacking in the southern Dauphinois Domain, probably due to a paleogeographic control. 

Surgical outcome of primary clipping for anterior circulation aneurysms of size 2 centimeters or larger.

Science.gov (United States)

Furtado, Sunil V; Saikiran, Narayanam A; Thakar, Sumit; Dadlani, Ravi; Mohan, Dilip; Aryan, Saritha; Hegde, Alangar S

2014-07-01

Aneurysms of the anterior circulation larger than 2cm have a complex relationship to the anterior skull base, requiring a multi-modality management approach. This retrospective study of 54 patients with such aneurysms who underwent clipping between 2001 and 2012 analyzes clinical and surgical data, aneurysm characteristics and correlates them with respect to the Glasgow outcome score at follow-up and immediate post-operative clinical status. Patients with an outcome score of 5 or 4 were categorized as "good", while those with score 3-1 were "poor". Fisher's exact test and paired T-test (p<0.5) were used to test statistical significance for discrete and continuous variables respectively. 44 (81.4%) patients had a good outcome. Patients with non-ophthalmic/paraclinoid aneurysms had significantly lower incidence of adverse intra-operative events (p=0.035). Patients older than 50 years (p=0.045), with adverse intra-operative events (p=0.015) and post-operative infarction (p<0.001) had a poor outcome compared to those younger than 50 years age and those without adverse intra-operative events or infarctions. The grouped age variable had maximum influence on patient outcome. Location and size of aneurysm did not have an overall impact on surgical outcome. There were 4 mortalities. Primary clipping of proximal non-cavernous aneurysms on the internal carotid artery is associated with adverse intra-operative events. A multi-modality treatment approach in these aneurysms should be individualized, more so in patients older than 50 years. Copyright © 2014 Elsevier B.V. All rights reserved.

Good performance of a titanium femoral component in cementless hip arthroplasty in younger patients: 97 arthroplasties followed for 5-11 years

DEFF Research Database (Denmark)

Jacobsen, Steffen; Jensen, Frank Krieger; Poulsen, Klaus

2003-01-01

We performed 97 uncemented primary total hip arthroplasties in 80 patients having an average age of 50 years. The femoral implant was a titanium stem with a proximal circumferential plasma spray-coating. Three different acetabular components were used: a threaded and partly porous-coated design i...... titanium femoral component with a circumferential porous coating performed well in these patients, most of whom were young. As reported previously, aseptic loosening of threaded acetabular components was common....

Are larger and/or more symmetrical Drosophila melanogaster (Diptera, Drosophilidae males more successful in matings in nature?

Directory of Open Access Journals (Sweden)

Sofija Pavković-Lučić

Full Text Available Are larger and/or more symmetrical Drosophila melanogaster (Diptera, Drosophilidae males more successful in matings in nature? Sexual selection in Drosophila melanogaster, related to body size and fluctuating asymmetry in wing length and number of sex comb teeth in males, was tested in natural conditions. Males collected in copula were significantly larger than those collected as a single, while no difference in mean number of sex comb teeth between copulating and single males was observed. On the other hand, single males had greater asymmetry both for wing length and number of sex comb teeth than their mating counterparts. It looks like that symmetry of these bilateral traits also may play a role in sexual selection in this dipteran species in nature.

Recombining overlapping BACs into a single larger BAC

Directory of Open Access Journals (Sweden)

Huxley Clare

2004-01-01

Full Text Available Abstract Background BAC clones containing entire mammalian genes including all the transcribed region and long range controlling elements are very useful for functional analysis. Sequenced BACs are available for most of the human and mouse genomes and in many cases these contain intact genes. However, large genes often span more than one BAC, and single BACs covering the entire region of interest are not available. Here we describe a system for linking two or more overlapping BACs into a single clone by homologous recombination. Results The method was used to link a 61-kb insert carrying the final 5 exons of the human CFTR gene onto a 160-kb BAC carrying the first 22 exons. Two rounds of homologous recombination were carried out in the EL350 strain of bacteria which can be induced for the Red genes. In the first round, the inserts of the two overlapping BACs were subcloned into modified BAC vectors using homologous recombination. In the second round, the BAC to be added was linearised with the very rare-cutting enzyme I-PpoI and electroporated into recombination efficient EL350 bacteria carrying the other BAC. Recombined BACs were identified by antibiotic selection and PCR screening and 10% of clones contained the correctly recombined 220-kb BAC. Conclusion The system can be used to link the inserts from any overlapping BAC or PAC clones. The original orientation of the inserts is not important and desired regions of the inserts can be selected. The size limit for the fragments recombined may be larger than the 61 kb used here and multiple BACs in a contig could be combined by alternating use of the two pBACLink vectors. This system should be of use to many investigators wishing to carry out functional analysis on large mammalian genes which are not available in single BAC clones.

Practical aspects of NMR signal assignment in larger and challenging proteins

Science.gov (United States)

Frueh, Dominique P.

2014-01-01

NMR has matured into a technique routinely employed for studying proteins in near physiological conditions. However, applications to larger proteins are impeded by the complexity of the various correlation maps necessary to assign NMR signals. This article reviews the data analysis techniques traditionally employed for resonance assignment and describes alternative protocols necessary for overcoming challenges in large protein spectra. In particular, simultaneous analysis of multiple spectra may help overcome ambiguities or may reveal correlations in an indirect manner. Similarly, visualization of orthogonal planes in a multidimensional spectrum can provide alternative assignment procedures. We describe examples of such strategies for assignment of backbone, methyl, and nOe resonances. We describe experimental aspects of data acquisition for the related experiments and provide guidelines for preliminary studies. Focus is placed on large folded monomeric proteins and examples are provided for 37, 48, 53, and 81 kDa proteins. PMID:24534088

4π Noncoplanar Stereotactic Body Radiation Therapy for Centrally Located or Larger Lung Tumors

International Nuclear Information System (INIS)

Dong, Peng; Lee, Percy; Ruan, Dan; Long, Troy; Romeijn, Edwin; Low, Daniel A.; Kupelian, Patrick; Abraham, John; Yang, Yingli; Sheng, Ke

2013-01-01

Purpose: To investigate the dosimetric improvements in stereotactic body radiation therapy for patients with larger or central lung tumors using a highly noncoplanar 4π planning system. Methods and Materials: This study involved 12 patients with centrally located or larger lung tumors previously treated with 7- to 9-field static beam intensity modulated radiation therapy to 50 Gy. They were replanned using volumetric modulated arc therapy and 4π plans, in which a column generation method was used to optimize the beam orientation and the fluence map. Maximum doses to the heart, esophagus, trachea/bronchus, and spinal cord, as well as the 50% isodose volume, the lung volumes receiving 20, 10, and 5 Gy were minimized and compared against the clinical plans. A dose escalation study was performed to determine whether a higher prescription dose to the tumor would be achievable using 4π without violating dose limits set by the clinical plans. The deliverability of 4π plans was preliminarily tested. Results: Using 4π plans, the maximum heart, esophagus, trachea, bronchus and spinal cord doses were reduced by 32%, 72%, 37%, 44%, and 53% (P≤.001), respectively, and R 50 was reduced by more than 50%. Lung V 20 , V 10 , and V 5 were reduced by 64%, 53%, and 32% (P≤.001), respectively. The improved sparing of organs at risk was achieved while also improving planning target volume (PTV) coverage. The minimal PTV doses were increased by the 4π plans by 12% (P=.002). Consequently, escalated PTV doses of 68 to 70 Gy were achieved in all patients. Conclusions: We have shown that there is a large potential for plan quality improvement and dose escalation for patients with larger or centrally located lung tumors using noncoplanar beams with sufficient quality and quantity. Compared against the clinical volumetric modulated arc therapy and static intensity modulated radiation therapy plans, the 4π plans yielded significantly and consistently improved tumor coverage and

4π Noncoplanar Stereotactic Body Radiation Therapy for Centrally Located or Larger Lung Tumors

Energy Technology Data Exchange (ETDEWEB)

Dong, Peng; Lee, Percy; Ruan, Dan [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States); Long, Troy; Romeijn, Edwin [Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, Michigan (United States); Low, Daniel A.; Kupelian, Patrick; Abraham, John; Yang, Yingli [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States); Sheng, Ke, E-mail: ksheng@mednet.ucla.edu [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States)

2013-07-01

Purpose: To investigate the dosimetric improvements in stereotactic body radiation therapy for patients with larger or central lung tumors using a highly noncoplanar 4π planning system. Methods and Materials: This study involved 12 patients with centrally located or larger lung tumors previously treated with 7- to 9-field static beam intensity modulated radiation therapy to 50 Gy. They were replanned using volumetric modulated arc therapy and 4π plans, in which a column generation method was used to optimize the beam orientation and the fluence map. Maximum doses to the heart, esophagus, trachea/bronchus, and spinal cord, as well as the 50% isodose volume, the lung volumes receiving 20, 10, and 5 Gy were minimized and compared against the clinical plans. A dose escalation study was performed to determine whether a higher prescription dose to the tumor would be achievable using 4π without violating dose limits set by the clinical plans. The deliverability of 4π plans was preliminarily tested. Results: Using 4π plans, the maximum heart, esophagus, trachea, bronchus and spinal cord doses were reduced by 32%, 72%, 37%, 44%, and 53% (P≤.001), respectively, and R{sub 50} was reduced by more than 50%. Lung V{sub 20}, V{sub 10}, and V{sub 5} were reduced by 64%, 53%, and 32% (P≤.001), respectively. The improved sparing of organs at risk was achieved while also improving planning target volume (PTV) coverage. The minimal PTV doses were increased by the 4π plans by 12% (P=.002). Consequently, escalated PTV doses of 68 to 70 Gy were achieved in all patients. Conclusions: We have shown that there is a large potential for plan quality improvement and dose escalation for patients with larger or centrally located lung tumors using noncoplanar beams with sufficient quality and quantity. Compared against the clinical volumetric modulated arc therapy and static intensity modulated radiation therapy plans, the 4π plans yielded significantly and consistently improved tumor

Comparison on the heat requirements of a four-span greenhouse with a melting snow system and a single-span greenhouse

International Nuclear Information System (INIS)

Furuno, S.; Sase, S.; Ishii, M.

2004-01-01

The heat requirements were measured and compared between a four-span greenhouse with a melting snow system and a typical single-span greenhouse with no melting snow system. Generally, single-span greenhouses require no melting snow system because snow drops off naturally from the roofs by gravity. The results for the four-span greenhouse showed that the provided heat by a heater for melting snow increased with an increase in snowfall, and there was a high correlation between them. The heat requirement per unit floor area of the four-span greenhouse was slightly less than that of the single-span greenhouse. This suggests that the decrease in heat requirement for internal air because of the larger floor/surface area ratio of the four-span greenhouse was more than the increase in heat requirement for melting snow. The measured heat requirement of the four-span greenhouse with the melting snow system was equal to the estimated heat load based on a common calculation procedure. On the other hand, that of the single-span greenhouse was slightly smaller than the estimated heat load. These suggest that the estimated heat load based on the common calculation procedure was slightly overestimated and larger than the actual heat requirement excluding the heat for the melting snow in snowy area. This is likely due to the fact that the parameters in the common calculation procedure were determined under the condition of larger net radiation than that in snowy area

Constellation-X to Generation-X: evolution of large collecting area moderate resolution grazing incidence x-ray telescopes to larger area high-resolution adjustable optics

Science.gov (United States)

Reid, Paul B.; Cameron, Robert A.; Cohen, Lester; Elvis, Martin; Gorenstein, Paul; Jerius, Diab; Petre, Robert; Podgorski, William A.; Schwartz, Daniel A.; Zhang, William W.

2004-10-01

Large collecting area x-ray telescopes are designed to study the early Universe, trace the evolution of black holes, stars and galaxies, study the chemical evolution of the Universe, and study matter in extreme environments. The Constellation-X mission (Con-X), planned for launch in 2016, will provide ~ 10^4 cm^2 collecting area with 15 arc-sec resolution, with a goal of 5 arc-sec. Future missions require larger collecting area and finer resolution. Generation-X (Gen-X), a NASA Visions Mission, will achieve 100 m^2 effective area at 1 keV and angular resolution of 0.1 arc-sec, half power diameter. We briefly describe the Con-X flowdown of imaging requirements to reflector figure error. To meet requirements beyond Con-X, Gen-X optics will be thinner and more accurately shaped than has ever been accomplished. To meet these challenging goals, we incorporate for the first time active figure control with grazing incidence optics. Piezoelectric material will be deposited in discrete cells directly on the back surface of the optical segments, with the strain directions oriented parallel to the surface. Differential strain between the two layers of the mirror causes localized bending in two directions, enabling local figure control. Adjusting figure on-orbit eases fabrication and metrology. The ability to make changes to mirror figure adds margin by mitigating risk due to launch-induced deformations and/or on-orbit degradation. We flowdown the Gen-X requirements to mirror figure and four telescope designs, and discuss various trades between the designs.

Ecological tolerances of Miocene larger benthic foraminifera from Indonesia

Science.gov (United States)

Novak, Vibor; Renema, Willem

2018-01-01

To provide a comprehensive palaeoenvironmental reconstruction based on larger benthic foraminifera (LBF), a quantitative analysis of their assemblage composition is needed. Besides microfacies analysis which includes environmental preferences of foraminiferal taxa, statistical analyses should also be employed. Therefore, detrended correspondence analysis and cluster analysis were performed on relative abundance data of identified LBF assemblages deposited in mixed carbonate-siliciclastic (MCS) systems and blue-water (BW) settings. Studied MCS system localities include ten sections from the central part of the Kutai Basin in East Kalimantan, ranging from late Burdigalian to Serravallian age. The BW samples were collected from eleven sections of the Bulu Formation on Central Java, dated as Serravallian. Results from detrended correspondence analysis reveal significant differences between these two environmental settings. Cluster analysis produced five clusters of samples; clusters 1 and 2 comprise dominantly MCS samples, clusters 3 and 4 with dominance of BW samples, and cluster 5 showing a mixed composition with both MCS and BW samples. The results of cluster analysis were afterwards subjected to indicator species analysis resulting in the interpretation that generated three groups among LBF taxa: typical assemblage indicators, regularly occurring taxa and rare taxa. By interpreting the results of detrended correspondence analysis, cluster analysis and indicator species analysis, along with environmental preferences of identified LBF taxa, a palaeoenvironmental model is proposed for the distribution of LBF in Miocene MCS systems and adjacent BW settings of Indonesia.

The cavity-nest ant Temnothorax crassispinus prefers larger nests.

Science.gov (United States)

Mitrus, S

Colonies of the ant Temnothorax crassispinus inhabit mostly cavities in wood and hollow acorns. Typically in the field, nest sites that can be used by the ant are a limited resource. In a field experiment, it was investigated whether the ants prefer a specific size of nest, when different ones are available. In July 2011, a total of 160 artificial nests were placed in a beech-pine forest. Four artificial nests (pieces of wood with volume cavities, ca 415, 605, 730, and 980 mm 3 , respectively) were located on each square meter of the experimental plot. One year later, shortly before the emergence of new sexuals, the nests were collected. In July 2012, colonies inhabited more frequently bigger nests. Among queenright colonies, the ones which inhabited bigger nests had more workers. However, there was no relationship between volume of nest and number of workers for queenless colonies. Queenright colonies from bigger nests produced more sexual individuals, but there was no correlation between number of workers and sex allocation ratio, or between volume of nest and sex allocation ratio. In a laboratory experiment where ant colonies were kept in 470 and 860 mm 3 nests, larger colonies allocated more energy to produce sexual individuals. The results of this study show the selectivity of T. crassispinus ants regarding the size of nest cavity, and that the nest volume has an impact on life history parameters.

Post-operative observation of ilio-apophyseal transplants on the basis of radiography, computed tomography, autoradiography and histological assessment

International Nuclear Information System (INIS)

Klatt, U.

1987-01-01

A study in 25 rabbits, in which the acetabular roof was reinforced by inserting a wedge-shaped autologous tissue fragment of the apophysis, led to the following conclusions: That complete healing and ossification of the implant took place within the observation period; that radiography, computed tomography, autoradiography and histology consistently provided evidence in confirmation of ossification; that a wedge-shaped fragment of apophyseal cartilage is a suitable material for plastic surgery in the acetabular roof. (TRV) [de

Revision hip replacement for recurrent Hydatid disease of the pelvis: a case report and review of the literature

Directory of Open Access Journals (Sweden)

Chandrasekar Coonoor R

2010-03-01

Full Text Available Abstract A case of a large recurrent hydatid cyst involving the right ilium and right hip treated with excision of the cyst, Total hip replacement and revision of the acetabular component with a Tripolar articulation for cyst recurrence and acetabular component loosening is presented along with a review of the relevant literature. To our knowledge there is no reported case of Total Hip replacement and revision for hydatid disease involving the bony pelvis.

Computed tomography vs. digital radiography assessment for detection of osteolysis in asymptomatic patients with uncemented cups: a proposal for a new classification system based on computer tomography.

Science.gov (United States)

Sandgren, Buster; Crafoord, Joakim; Garellick, Göran; Carlsson, Lars; Weidenhielm, Lars; Olivecrona, Henrik

2013-10-01

Digital radiographic images in the anterior-posterior and lateral view have been gold standard for evaluation of peri-acetabular osteolysis for patients with an uncemented hip replacement. We compared digital radiographic images and computer tomography in detection of peri-acetabular osteolysis and devised a classification system based on computer tomography. Digital radiographs were compared with computer tomography on 206 hips, with a mean follow up 10 years after surgery. The patients had no clinical signs of osteolysis and none were planned for revision surgery. On digital radiographs, 192 cases had no osteolysis and only 14 cases had osteolysis. When using computer tomography there were 184 cases showing small or large osteolysis and only 22 patients had no osteolysis. A classification system for peri-acetabular osteolysis is proposed based on computer tomography that is easy to use on standard follow up evaluation. Copyright © 2013 Elsevier Inc. All rights reserved.

When gains loom larger than losses: reversed loss aversion for small amounts of money.

Science.gov (United States)

Harinck, Fieke; Van Dijk, Eric; Van Beest, Ilja; Mersmann, Paul

2007-12-01

Previous research has generally shown that people are loss averse; that is, they weigh losses more heavily than gains. In a series of three experiments, we found that for small outcomes, this pattern is reversed, and gains loom larger than losses. We explain this reversal on the basis of (a) the hedonic principle, which states that individuals are motivated to maximize pleasure and to minimize pain, and (b) the assumption that small losses are more easily discounted cognitively than large losses are.

A Prolonged Time Interval Between Trauma and Prophylactic Radiation Therapy Significantly Increases the Risk of Heterotopic Ossification

Energy Technology Data Exchange (ETDEWEB)

Mourad, Waleed F., E-mail: Waleed246@gmail.com [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS (United States); Department of Radiation Oncology, Beth Israel Medical Center, New York, NY (Israel); Packianathan, Satyaseelan [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS (United States); Shourbaji, Rania A. [Department of Epidemiology and Biostatistics, Jackson State University, Jackson, MS (United States); Zhang Zhen; Graves, Mathew [Department of Orthopedic Surgery, University of Mississippi Medical Center, Jackson, MS (United States); Khan, Majid A. [Department of Radiology, University of Mississippi Medical Center, Jackson, MS (United States); Baird, Michael C. [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS (United States); Russell, George [Department of Orthopedic Surgery, University of Mississippi Medical Center, Jackson, MS (United States); Vijayakumar, Srinivasan [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS (United States)

2012-03-01

Purpose: To ascertain whether the time from injury to prophylactic radiation therapy (RT) influences the rate of heterotopic ossification (HO) after operative treatment of displaced acetabular fractures. Methods and Materials: This is a single-institution, retrospective analysis of patients referred for RT for the prevention of HO. Between January 2000 and January 2009, 585 patients with displaced acetabular fractures were treated surgically followed by RT for HO prevention. We analyzed the effect of time from injury on prevention of HO by RT. In all patients, 700 cGy was prescribed in a single fraction and delivered within 72 hours postsurgery. The patients were stratified into five groups according to time interval (in days) from the date of their accident to the date of RT: Groups A {<=}3, B {<=}7, C {<=}14, D {<=}21, and E >21days. Results: Of the 585 patients with displaced acetabular fractures treated with RT, (18%) 106 patients developed HO within the irradiated field. The risk of HO after RT increased from 10% for RT delivered {<=}3 days to 92% for treatment delivered >21 days after the initial injury. Wilcoxon test showed a significant correlation between the risk of HO and the length of time from injury to RT (p < 0.0001). Chi-square test and multiple logistic regression analysis showed no significant association between all other factors and the risk of HO (race, gender, cause and type of fracture, surgical approach, or the use of indomethacin). Conclusions: Our data suggest that there is higher incidence and risk of HO if prophylactic RT is significantly delayed after a displaced acetabular fracture. Thus, RT should be administered as early as clinically possible after the trauma. Patients undergoing RT >3 weeks from their displaced acetabular fracture should be informed of the higher risk (>90%) of developing HO despite prophylaxis.

Revision of cemented hip arthroplasty using a hydroxyapatite-ceramic-coated femoral component.

Science.gov (United States)

Raman, R; Kamath, R P; Parikh, A; Angus, P D

2005-08-01

We report the clinical and radiological outcome of 86 revisions of cemented hip arthroplasties using JRI-Furlong hydroxyapatite-ceramic-coated acetabular and femoral components. The acetabular component was revised in 62 hips and the femoral component in all hips. The mean follow-up was 12.6 years and no patient was lost to follow-up. The mean age of the patients was 71.2 years. The mean Harris hip and Oxford scores were 82 (59 to 96) and 23.4 (14 to 40), respectively. The mean Charnley modification of the Merle d'Aubigné and Postel score was 5 (3 to 6) for pain, 4.9 (3 to 6) for movement and 4.4 (3 to 6) for mobility. Migration of the acetabular component was seen in two hips and the mean acetabular inclination was 42.6 degrees. The mean linear polyethylene wear was 0.05 mm/year. The mean subsidence of the femoral component was 1.9 mm and stress shielding was seen in 23 (28%) with bony ingrowth in 76 (94%). Heterotopic ossification was seen in 12 hips (15%). There were three re-revisions, two for deep sepsis and one for recurrent dislocation and there were no re-revisions for aseptic loosening. The mean EuroQol EQ-5D description scores and health thermometer scores were 0.69 (0.51 to 0.89) and 79 (54 to 95), respectively. With an end-point of definite or probable loosening, the probability of survival at 12 years was 93.9% and 95.6% for the acetabular and femoral components, respectively. Overall survival at 12 years, with removal or further revision of either component for any reason as the end-point, was 92.3%. Our study supports the continued use of this arthroplasty and documents the durability of hydroxyapatite-ceramic-coated components.

Elevated lip liner positions improving stability in total hip arthroplasty. An experimental study.

Directory of Open Access Journals (Sweden)

Suleman Qurashi

2018-01-01

Full Text Available Background: The use of elevated lip polyethylene liners with the acetabular component is relatively common in Total Hip Arthroplasty (THA. Elevated lip liners increase stability of the THA by increasing the jump distance in one direction. However, the elevated lip, conversely, also reduces the primary arc in the opposite direction and leads to early impingement of the neck on the elevated lip, potentially causing instability. The aim of the present study is to determine the total range of motion of the femoral head component within the acetabular component with the elevated lip liner in different orientations within the acetabular cup. Methods: We introduce a novel experimental (ex-vivo framework for studying the effects lip liner orientation on the range of motion of the femoral component. For constant acetabular cup orientation, the elevated lip liner was positioned superiorly and inferiorly. The femoral component range of motion in the coronal, sagittal and axial plane was measured. To avoid any confounding influences of out of plane motion, the femoral component was constrained to move in the tested plane. Results: This experimental set up introduces a rigorous framework in which to test the effects of elevated lip liner orientations on the range of motion of the femoral head component in abduction, adduction, flexion, extension and rotation. The movements of this experimental set-up are directly informative of patient’s maximum potential post-operative range of motion. Initial results show that an inferior placement of the elevated lip increases the effective superior lateral range of motion (abduction for the femoral component, whilst the anatomy of the patient (i.e. their other leg prevents the point of femoral component – acetabular lip impingement being reached (in adduction.

Materials requirements for liquid metal fast breeder reactors

International Nuclear Information System (INIS)

Bennett, J.W.; Horton, K.E.

1978-01-01

Materials requirements for Liquid Metal Fast Breeder Reactors (LMFBRs) are quite varied with requisite applications ranging from ex-reactor components such as piping, pumps, steam generators and heat exchangers to in-reactor components such as heavy section reactor vessels, core structurals, fuel pin cladding and subassembly flow ducts. Requirements for ex-reactor component materials include: good high temperature tensile, creep and fatigue properties; compatibility with high temperature flowing sodium; resistance to wear, stress corrosion cracking, and crack propagation; and good weldability. Requirements for in-reactor components include most of those cited above for ex-reactor components as supplemented by the following: resistance to radiation embrittlement, swelling and radiation enhanced creep; good neutronics; compatibility with fuel and fission product materials; and resistance to mass transfer via flowing sodium. Extensive programs are currently in place in a number of national laboratories and industrial contractors to address the materials requirements for LMFBRs. These programs are focused on meeting the near term requirements of early LMFBRs such as the Fast Flux Test Facility and the Clinch River Breeder Reactor as well as the longer term requirements of larger near-commercial and fully-commercial reactors

Trophic interactions between larger crocodylians and giant tortoises on Aldabra Atoll, Western Indian Ocean, during the Late Pleistocene.

Science.gov (United States)

Scheyer, Torsten M; Delfino, Massimo; Klein, Nicole; Bunbury, Nancy; Fleischer-Dogley, Frauke; Hansen, Dennis M

2018-01-01

Today, the UNESCO World Heritage Site of Aldabra Atoll is home to about 100 000 giant tortoises, Aldabrachelys gigantea , whose fossil record goes back to the Late Pleistocene. New Late Pleistocene fossils (age ca . 90-125 000 years) from the atoll revealed some appendicular bones and numerous shell fragments of giant tortoises and cranial and postcranial elements of crocodylians. Several tortoise bones show circular holes, pits and scratch marks that are interpreted as bite marks of crocodylians. The presence of a Late Pleistocene crocodylian species, Aldabrachampsus dilophus , has been known for some time, but the recently found crocodylian remains presented herein are distinctly larger than those previously described. This indicates the presence of at least some larger crocodylians, either of the same or of a different species, on the atoll. These larger crocodylians, likely the apex predators in the Aldabra ecosystem at the time, were well capable of inflicting damage on even very large giant tortoises. We thus propose an extinct predator-prey interaction between crocodylians and giant tortoises during the Late Pleistocene, when both groups were living sympatrically on Aldabra, and we discuss scenarios for the crocodylians directly attacking the tortoises or scavenging on recently deceased animals.

Risk factors for the need of hip arthroscopy following periacetabular osteotomy

Science.gov (United States)

Hartig-Andreasen, Charlotte; Troelsen, Anders; Thillemann, Theis M.; Gelineck, John; Søballe, Kjeld

2015-01-01

Despite the frequency of labral tears in symptomatic developmental dysplasia of the hip, no consensus exists regarding the treatment of coexisting dysplasia of the hip and tearing of the acetabular labrum. The purpose of this prospective, MR arthrography (MRA) based 2-year follow-up study was to identify risk factors predicting the need for a hip arthroscopy (HA) after periacetabular osteotomy (PAO). Ninety-nine patients (104 hips) scheduled for PAO were evaluated preoperatively and at 2-year follow-up. MRA was performed in all patients prior to PAO. At follow-up, patients were divided into a non-arthroscopy and arthroscopy group. The two groups were compared clinical and radiological, and risk factors for HA after PAO were calculated. Patient reported outcome measures (WOMAC, Oxford Hip and SF36) were filled out before PAO and at follow-up. Ninety-five hips (91.3%) were evaluated. Twenty-six hips (27%) required an arthroscopy within 2 years of the PAO. Risk factors were preoperative borderline dysplasia, acetabular retroversion and complete labral detachment. Labral tearing, degeneration or hypertrophy did not negatively affect the outcome of PAO. Patients not requiring an arthroscopy had a statistically significant better outcome measured by patients reported outcome measures. After PAO, 27% of the hips needed intra-articular assessment. Conventional radiographs and MRA analysis can be used to identify predictors for patients requiring HA after PAO. At 2-year follow-up, the clinical outcome improved in all patients. However, those patients who had no need of a HA after their PAO had superior results. PMID:27011862

Requirements of office air conditioners. Pt. 1

Energy Technology Data Exchange (ETDEWEB)

Radtke, W

1988-01-01

New building designs and experiences gained in the past are reponsible for the considerable changes the requirements of air conditioners have gone through in recent years. Details are given on an exemplary air conditioning system designed for the Colonia Insurances building complex located in the city of Cologne. The ventilation requirements and hygienic conditions set out for air conditioned rooms call for outside air supplies, the careful selection of air intakes, and the filtering of intake air. Details are given on the efficiency and limits of combined natural window ventilation/artificial ventilation systems, the influence of window types, and the influence of building structures. The pressure conditions to be expected for larger building complexes in the case of natural ventilation should be assessed with the help of models put to wind tunnel tests.

Influence of cup-center-edge angle on micro-motion at the interface between the cup and host bone in cementless total hip arthroplasty: three-dimensional finite element analysis.

Science.gov (United States)

Kaku, Nobuhiro; Tabata, Tomonori; Tsumura, Hiroshi

2015-12-01

We verified the index cup position required for bulk bone grafting instead of morcellized grafting immediately after cementless total hip arthroplasty. Three-dimensional finite element analysis was used to evaluate changes in the volume of the slippage of the cup-host bone interface as micro-motion of the cup at the acetabular bone defect site depending on the cup-center-edge (CE) angle. The conditions of bulk bone grafts were similar to those of cortical bone. Slippage increased with decreasing cup-CE angle. A bulk bone graft tightly fixed to the host bone prevented considerably larger slippage between the cup and host bone. A smaller cup-CE angle increased the impact of the bulk bone graft on slippage. When the cup-CE angle was 0° or -10°, the criterion for slippage in favorable initial fixation in all conditions was cup and bone graft, it is impossible to obtain reliable fixation of the cup with a cup-CE angle cup-host bone fixation, especially when the cup-CE angle is small, such as cups, and sufficient fixation between the host bone and cup or bulk bone graft using a screw is effective when the cup-CE angle is extremely small.

Unmanned Aerial Vehicle/Remotely Piloted Aircraft Design Selection Based on Service-Stated Meteorological/Oceanographic Requirements

National Research Council Canada - National Science Library

Stanton, Robert

1999-01-01

... (written in Structured Query Language) links RPA flight performance parameters to individualized METOC Elements of Measurement, a subset of a larger Joint Service METOC Requirements database table, presented elsewhere in the thesis in full...

Procedure DEGA type by double approach

International Nuclear Information System (INIS)

Sanchez Mesa, Pedro Antonio; Yarnhure Helo, Fernando

2004-01-01

The following is an observational, retrospective, descriptive study, including case studies of patients with developmental acetabular dysplasia of the hip with neuromuscular changes. We examined (11) eleven hips in (3) three women and (5) five men who undergone incomplete marginal trans-iliac DEGA osteotomy in the form of a semicircular acetabuloplasty with double surgical approach, performed in conjunction with a previous open reduction and a femoral variant twisting osteotomy. We evaluated these patients with 3DCAT scan and simple x-ray. The following were evaluated: the acetabular depth, the percentage of lateral and anterior femoral head extrusion, the center edge, anterior wall deficit, sharp angle, acetabular anteversion, percentage of unoccupied medial acetabulum and center rotation asymmetry, sphericity of the femoral head (Mose), acetabular support angle (WBZ) (Bombelliand Aronson), migration percentage (Reimers), articular consistency (Coleman), and the arthrosis according to Tonnis. The clinical follow up was carried out for 24.6 months on average, with radiological three dimensional Tomographic scans up to 23.6 months with an interval of between 6 and 49 months. Results were excellent in 80% of the cases, good in 14%, regular in 0%, bad in 6%. The results suggest that this a good alternative in the treatment of dysplasia in a number of patients, bearing in mind their indications and contraindications as well as the magnitude of correction that can be expected

USING CUSTOM TRIFLANGE IMPLANT IN REVISION HIP ARTHROPLASTY IN PATIENT WITH PELVIC DISCONTINUITY (CASE REPORT

Directory of Open Access Journals (Sweden)

R. M. Tikhilov

2016-01-01

Full Text Available Revision hip arthroplasty rate is growing, and pelvic discontinuity rate ranges from 1% to 5% of acetabular component revision reasons. According to AAOS acetabular defects classification, pelvic discontinuity is fourth type defect in which cranial part of hip bone is separated from caudal part at acetabular level. Usually it occurs from bone loss secondary to osteolysis, infection, fracture or aseptic loosening. There are a lot of techniques for pelvis discontinuity treatment. Published results of bulk allografts and antiprotrusion cages have generally been poor. More preferable methods with acceptable rate of good results are cup-cage systems and custom triflange acetabular components(CTAC. CTACs are designed based on preoperative CT scans to build a custom titanium 3D-printed implant to address the patient's specific bone defect and provide secure fixation in the ilium, pubis, and ischium. We faced pelvic discontinuity, in which extensive iliac bone loss was added to caudal hip bone part medial displacement and pelvic ring deformity, in patient with multiple hip surgeries. Preoperative investigation called into question the possibility of using off-the-shelf hip implants, which could restore the biomechanics of the hip and provide reliable primary fixation at the same time. We present case report of the patient with pelvic discontinuity and massive bone loss treatment using a custom triflange component.

Rotational profile of the lower extremity in achondroplasia: computed tomographic examination of 25 patients

Energy Technology Data Exchange (ETDEWEB)

Song, Hae-Ryong; Suh, Seung-Woo [Korea University Guro Hospital, Department of Orthopaedic Surgery, Rare Diseases Institute, Seoul (Korea); Choonia, Abi-Turab [Laud Clinic, Department of Orthopaedic Surgery, Mumbai (India); Hong, Suk Joo; Cha, In Ho [Korea University Guro Hospital, Department of Radiology, Seoul (Korea); Lee, Seok-Hyun [Dongguk University Ilsan Buddist Hospital, Department of Orthopaedic Surgery, Goyang (Korea); Park, Jong-Tae [Korea University Ansan Hospital, Department of Occupational and Enviornmental Medicine, Ansan (Korea)

2006-12-15

To evaluate lower-extremity rotational abnormalities in subjects with achondroplasia using computed tomography (CT) scans. CT scans were performed in 25 subjects with achondroplasia (13 skeletally immature, mean age 8.7 years; 12 skeletally mature, mean age 17.6 years). In a total of 50 bilateral limbs, CT images were used to measure the angles of acetabular anteversion, femoral anteversion, and tibial external torion. Measurement was performed by three examiners and then repeated by one examiner. Inter- and intraobserver agreements were analyzed, and results were compared with previously reported normal values. Mean values for skeletally immature and skeletally mature subjects were 13.6{+-}7.5 and 21.5{+-}6.4 respectively for acetabular anteversion, 27.1{+-}20.8 and 30.5{+-}20.1 for femoral torsion, and 21.6{+-}10.6 and 22.5{+-}10.8 for tibial torsion. Intra- and interobserver agreements were good to excellent. Acetabular anteversion and femoral anteversion in skeletally mature subjects were greater than normal values in previous studies. Both skeletally immature and mature subjects with achondroplasia had decreased tibial torsion compared to normal skeletally immature and mature subjects. Lower-extremity rotational abnormalities in subjects with achondroplasia include decreased tibial external torsion in both skeletally immature and mature subjects, as well as increased femoral and acetabular anteversion in skeletally mature subjects. (orig.)

Rotational profile of the lower extremity in achondroplasia: computed tomographic examination of 25 patients

International Nuclear Information System (INIS)

Song, Hae-Ryong; Suh, Seung-Woo; Choonia, Abi-Turab; Hong, Suk Joo; Cha, In Ho; Lee, Seok-Hyun; Park, Jong-Tae

2006-01-01

To evaluate lower-extremity rotational abnormalities in subjects with achondroplasia using computed tomography (CT) scans. CT scans were performed in 25 subjects with achondroplasia (13 skeletally immature, mean age 8.7 years; 12 skeletally mature, mean age 17.6 years). In a total of 50 bilateral limbs, CT images were used to measure the angles of acetabular anteversion, femoral anteversion, and tibial external torion. Measurement was performed by three examiners and then repeated by one examiner. Inter- and intraobserver agreements were analyzed, and results were compared with previously reported normal values. Mean values for skeletally immature and skeletally mature subjects were 13.6±7.5 and 21.5±6.4 respectively for acetabular anteversion, 27.1±20.8 and 30.5±20.1 for femoral torsion, and 21.6±10.6 and 22.5±10.8 for tibial torsion. Intra- and interobserver agreements were good to excellent. Acetabular anteversion and femoral anteversion in skeletally mature subjects were greater than normal values in previous studies. Both skeletally immature and mature subjects with achondroplasia had decreased tibial torsion compared to normal skeletally immature and mature subjects. Lower-extremity rotational abnormalities in subjects with achondroplasia include decreased tibial external torsion in both skeletally immature and mature subjects, as well as increased femoral and acetabular anteversion in skeletally mature subjects. (orig.)

The Larger Bound on the Domination Number of Fibonacci Cubes and Lucas Cubes

Directory of Open Access Journals (Sweden)

Shengzhang Ren

2014-01-01

Full Text Available Let Γn and Λn be the n-dimensional Fibonacci cube and Lucas cube, respectively. Denote by Γ[un,k,z] the subgraph of Γn induced by the end-vertex un,k,z that has no up-neighbor. In this paper, the number of end-vertices and domination number γ of Γn and Λn are studied. The formula of calculating the number of end-vertices is given and it is proved that γ(Γ[un,k,z]≤2k-1+1. Using these results, the larger bound on the domination number γ of Γn and Λn is determined.

Experiences of young women living with developmental dysplasia of the hip: insight into their experiences of surgery and recovery.

Science.gov (United States)

Gambling, Tina S; Long, Andrew F

2013-03-01

To explore the experiences of young women with developmental dysplasia of the hip explicating the impact of peri-acetabular osteotomy surgery and recovery in the short and longer term. Postings of five, selected women on an online active message board aimed at women with developmental dysplasia of the hip were analysed. Interest lay on their postings after they had had peri-acetabular osteotomy surgery. Data analysis was performed through the approach of interpretive phenomenological analysis. The time length of the postings for the cases ranged from 1 year to 6 years, and the number of postings varied substantially, from 48 to 591. Two major concepts were prominent across participants' accounts. The first concept, 'body image', centred on affects on the women's self-esteem and body image. The second, 'the long road to recovery', highlighted 'the emotional and physical battle of learning to walk' and concerns with 'saving my joints'. Developmental dysplasia of the hip potentially provides a critical case for exploration of the process of how a disability can affect confidence, self-esteem and body image. Recovery from this condition requires enormous effort, resilience and commitment from the women.

Ventricular arrhythmia burst is an independent indicator of larger infarct size even in optimal reperfusion in STEMI

NARCIS (Netherlands)

van der Weg, Kirian; Majidi, Mohamed; Haeck, Joost D. E.; Tijssen, Jan G. P.; Green, Cynthia L.; Koch, Karel T.; Kuijt, Wichert J.; Krucoff, Mitchell W.; Gorgels, Anton P. M.; de Winter, Robbert J.

2016-01-01

We hypothesized that ventricular arrhythmia (VA) bursts during reperfusion phase are a marker of larger infarct size despite optimal epicardial and microvascular perfusion. 126 STEMI patients were studied with 24h continuous, 12-lead Holter monitoring. Myocardial blush grade (MBG) was determined and

Laser-Induced Damage Growth on Larger-Aperture Fused Silica Optical Components at 351 nm

International Nuclear Information System (INIS)

Wan-Qing, Huang; Wei, Han; Fang, Wang; Yong, Xiang; Fu-Quan, Li; Bin, Feng; Feng, Jing; Xiao-Feng, Wei; Wan-Guo, Zheng; Xiao-Min, Zhang

2009-01-01

Laser-induced damage is a key lifetime limiter for optics in high-power laser facility. Damage initiation and growth under 351 nm high-fluence laser irradiation are observed on larger-aperture fused silica optics. The input surface of one fused silica component is damaged most severely and an explanation is presented. Obscurations and the area of a scratch on it are found to grow exponentially with the shot number. The area of damage site grows linearly. Micrographs of damage sites support the micro-explosion damage model which could be used to qualitatively explain the phenomena

Elevated outcome-anticipation and outcome-evaluation ERPs associated with a greater preference for larger-but-delayed rewards.

Science.gov (United States)

Pornpattananangkul, Narun; Nadig, Ajay; Heidinger, Storm; Walden, Keegan; Nusslock, Robin

2017-06-01

Although waiting for a reward reduces or discounts its value, some people have a stronger tendency to wait for larger rewards and forgo smaller-but-immediate rewards. This ability to delay gratification is captured by individual differences in so-called intertemporal choices in which individuals are asked to choose between larger-but-delayed versus smaller-but-immediate rewards. The current study used event-related potentials (ERPs) to examine whether enhancement in two neurocognitive processes, outcome anticipation and outcome evaluation, modulate individual variability in intertemporal responses. After completing a behavioral intertemporal choice task, 34 participants performed an ERP gambling task. From this ERP task, we separately examined individual differences in outcome anticipation (stimulus-preceding negativity; SPN), early outcome valuation (feedback-related negativity; FRN), and late outcome evaluation (P3). We observed that both elevated outcome-anticipation (SPN) and late outcome-evaluation (P3) neural processes predicted a stronger preference toward larger-but-delayed rewards. No relationship was observed between intertemporal responses and early outcome evaluation (FRN), indicating that the relationship between outcome evaluation and intertemporal responses was specific to the late outcome-evaluation processing stream. Moreover, multiple regression analyses indicated that the SPN and P3 independently modulate individual differences in intertemporal responses, suggesting separate mechanisms underlie the relationship between these two neurocognitive processes and intertemporal responses. Accordingly, we identify two potential neurocognitive modulators of individual variability in intertemporal responses. We discuss the mechanisms underlying these modulators in terms of anticipation-related processing (SPN) and a saliency bias toward gain (compared to loss) outcomes (P3).

Global warming may disproportionately affect larger adults in a predatory coral reef fish

KAUST Repository

Messmer, Vanessa

2016-11-03

Global warming is expected to reduce body sizes of ectothermic animals. Although the underlying mechanisms of size reductions remain poorly understood, effects appear stronger at latitudinal extremes (poles and tropics) and in aquatic rather than terrestrial systems. To shed light on this phenomenon, we examined the size dependence of critical thermal maxima (CTmax) and aerobic metabolism in a commercially important tropical reef fish, the leopard coral grouper (Plectropomus leopardus) following acclimation to current-day (28.5 °C) vs. projected end-of-century (33 °C) summer temperatures for the northern Great Barrier Reef (GBR). CTmax declined from 38.3 to 37.5 °C with increasing body mass in adult fish (0.45-2.82 kg), indicating that larger individuals are more thermally sensitive than smaller conspecifics. This may be explained by a restricted capacity for large fish to increase mass-specific maximum metabolic rate (MMR) at 33 °C compared with 28.5 °C. Indeed, temperature influenced the relationship between metabolism and body mass (0.02-2.38 kg), whereby the scaling exponent for MMR increased from 0.74 ± 0.02 at 28.5 °C to 0.79 ± 0.01 at 33 °C, and the corresponding exponents for standard metabolic rate (SMR) were 0.75 ± 0.04 and 0.80 ± 0.03. The increase in metabolic scaling exponents at higher temperatures suggests that energy budgets may be disproportionately impacted in larger fish and contribute to reduced maximum adult size. Such climate-induced reductions in body size would have important ramifications for fisheries productivity, but are also likely to have knock-on effects for trophodynamics and functioning of ecosystems.

Global warming may disproportionately affect larger adults in a predatory coral reef fish

KAUST Repository

Messmer, Vanessa; Pratchett, Morgan S.; Hoey, Andrew S.; Tobin, Andrew J.; Coker, Darren James; Cooke, Steven J.; Clark, Timothy D.

2016-01-01

Global warming is expected to reduce body sizes of ectothermic animals. Although the underlying mechanisms of size reductions remain poorly understood, effects appear stronger at latitudinal extremes (poles and tropics) and in aquatic rather than terrestrial systems. To shed light on this phenomenon, we examined the size dependence of critical thermal maxima (CTmax) and aerobic metabolism in a commercially important tropical reef fish, the leopard coral grouper (Plectropomus leopardus) following acclimation to current-day (28.5 °C) vs. projected end-of-century (33 °C) summer temperatures for the northern Great Barrier Reef (GBR). CTmax declined from 38.3 to 37.5 °C with increasing body mass in adult fish (0.45-2.82 kg), indicating that larger individuals are more thermally sensitive than smaller conspecifics. This may be explained by a restricted capacity for large fish to increase mass-specific maximum metabolic rate (MMR) at 33 °C compared with 28.5 °C. Indeed, temperature influenced the relationship between metabolism and body mass (0.02-2.38 kg), whereby the scaling exponent for MMR increased from 0.74 ± 0.02 at 28.5 °C to 0.79 ± 0.01 at 33 °C, and the corresponding exponents for standard metabolic rate (SMR) were 0.75 ± 0.04 and 0.80 ± 0.03. The increase in metabolic scaling exponents at higher temperatures suggests that energy budgets may be disproportionately impacted in larger fish and contribute to reduced maximum adult size. Such climate-induced reductions in body size would have important ramifications for fisheries productivity, but are also likely to have knock-on effects for trophodynamics and functioning of ecosystems.

Global warming may disproportionately affect larger adults in a predatory coral reef fish.

Science.gov (United States)

Messmer, Vanessa; Pratchett, Morgan S; Hoey, Andrew S; Tobin, Andrew J; Coker, Darren J; Cooke, Steven J; Clark, Timothy D

2017-06-01

Global warming is expected to reduce body sizes of ectothermic animals. Although the underlying mechanisms of size reductions remain poorly understood, effects appear stronger at latitudinal extremes (poles and tropics) and in aquatic rather than terrestrial systems. To shed light on this phenomenon, we examined the size dependence of critical thermal maxima (CTmax) and aerobic metabolism in a commercially important tropical reef fish, the leopard coral grouper (Plectropomus leopardus) following acclimation to current-day (28.5 °C) vs. projected end-of-century (33 °C) summer temperatures for the northern Great Barrier Reef (GBR). CTmax declined from 38.3 to 37.5 °C with increasing body mass in adult fish (0.45-2.82 kg), indicating that larger individuals are more thermally sensitive than smaller conspecifics. This may be explained by a restricted capacity for large fish to increase mass-specific maximum metabolic rate (MMR) at 33 °C compared with 28.5 °C. Indeed, temperature influenced the relationship between metabolism and body mass (0.02-2.38 kg), whereby the scaling exponent for MMR increased from 0.74 ± 0.02 at 28.5 °C to 0.79 ± 0.01 at 33 °C, and the corresponding exponents for standard metabolic rate (SMR) were 0.75 ± 0.04 and 0.80 ± 0.03. The increase in metabolic scaling exponents at higher temperatures suggests that energy budgets may be disproportionately impacted in larger fish and contribute to reduced maximum adult size. Such climate-induced reductions in body size would have important ramifications for fisheries productivity, but are also likely to have knock-on effects for trophodynamics and functioning of ecosystems. © 2016 John Wiley & Sons Ltd.

Hip2Norm: an object-oriented cross-platform program for 3D analysis of hip joint morphology using 2D pelvic radiographs.

Science.gov (United States)

Zheng, G; Tannast, M; Anderegg, C; Siebenrock, K A; Langlotz, F

2007-07-01

We developed an object-oriented cross-platform program to perform three-dimensional (3D) analysis of hip joint morphology using two-dimensional (2D) anteroposterior (AP) pelvic radiographs. Landmarks extracted from 2D AP pelvic radiographs and optionally an additional lateral pelvic X-ray were combined with a cone beam projection model to reconstruct 3D hip joints. Since individual pelvic orientation can vary considerably, a method for standardizing pelvic orientation was implemented to determine the absolute tilt/rotation. The evaluation of anatomically morphologic differences was achieved by reconstructing the projected acetabular rim and the measured hip parameters as if obtained in a standardized neutral orientation. The program had been successfully used to interactively objectify acetabular version in hips with femoro-acetabular impingement or developmental dysplasia. Hip(2)Norm is written in object-oriented programming language C++ using cross-platform software Qt (TrollTech, Oslo, Norway) for graphical user interface (GUI) and is transportable to any platform.

Working with and promoting early career scientists within a larger community

Science.gov (United States)

Pratt, K.

2017-12-01

For many scientific communities, engaging early career researchers is critical for success. These young scientists (graduate students, postdocs, and newly appointed professors) are actively forming collaborations and instigating new research programs. They also stand to benefit hugely from being part of a scientific community, gaining access to career development activities, becoming part of strong collaborator networks, and achieving recognition in their field of study — all of which will help their professional development. There are many ways community leaders can work proactively to support and engage early career scientists, and it it is often a community manager's job to work with leadership to implement such activities. In this presentation, I will outline ways of engaging early career scientists at events and tailored workshops, of promoting development of their leadership skills, and of creating opportunities for recognizing early career scientists within larger scientific communities. In this talk, I will draw from my experience working with the Deep Carbon Observatory Early Career Scientist Network, supported by the Alfred P. Sloan Foundation.

Origami-inspired metamaterial absorbers for improving the larger-incident angle absorption

International Nuclear Information System (INIS)

Shen, Yang; Pang, Yongqiang; Wang, Jiafu; Ma, Hua; Pei, Zhibin; Qu, Shaobo

2015-01-01

When a folded resistive patch array stands up on a metallic plane, it can exhibit more outstanding absorption performance. Our theoretical investigations and simulations demonstrated that the folded resistive patch arrays can enhance the absorption bandwidth progressively with the increase of the incident angle for the oblique transverse magnetic incidence, which is contrary to the conventional resistive frequency selective surface absorber. On illumination, we achieved a 3D structure metamaterial absorber with the folded resistive patches. The proposed absorber is obtained from the inspiration of the origami, and it has broadband and lager-incident angle absorption. Both the simulations and the measurements indicate that the proposed absorber achieves the larger-incident angle absorption until 75° in the frequency band of 3.6–11.4 GHz. In addition, the absorber is extremely lightweight. The areal density of the fabricated sample is about 0.023 g cm −2 . Due to the broadband and lager-incident angle absorption, it is expected that the absorbers may find potential applications such as stealth technologies and electromagnetic interference. (paper)

Microgravity Science Experiment of Marangoni Convection occurred in Larger Liquid Bridge on KIBO

Science.gov (United States)

Matsumoto, Satoshi; Yoda, Shinichi; Tanaka, Tetsuo

Marangoni convection is a fluid motion induced by local variations of surface tension along a free surface which is caused by temperature and/or concentration differences. Marangoni convection plays important roll in such applications as crystal growth from melt, welding, con-tainerless material processing, and so on. One of the promising techniques to grow a high quality crystal is a floating-zone method which exists cylindrical melting part at heated region. This liquid part like a column is sustained between solid rods and it has free surface on the side. For investigation of Marangoni convection, a liquid bridge configuration with heated top and cooled bottom is often employed to simplify phenomena. Much work has been performed on Marangoni convection in the past, both experimentally and theoretically. Most of the ex-perimental investigations were conducted in normal gravity but some results from microgravity experiments are now available. However, problems to be solved are still remained in scientific view point. The effect of liquid bridge size on critical Marangoni number to determine the onset of oscillatory flow is one of important subjects. To investigate size effect, the experiment with changing wide range of diameter is needed. Under terrestrial conditions, large size of liquid bridge enhances to induce buoyancy convection. Much larger liquid bridge is deformed its shape or finally liquid bridge could not keep between disks because of its self-weight. So, microgravity experiment is required to make clear the size effect and to obtain precise data. We carried out Marangoni experiment under microgravity condition in Japanese Experiment Module "KIBO". A 50 mm diameter liquid bridge was formed and temperature difference between supporting rods was imposed to induce thermocapillary flow. Convective motion was observed in detail using several cameras, infrared camera and temperature sensors. Silicone oil of 5cSt was employed as a working fluid, which Prandtl

Transmissible Plasmids and Integrons Shift Escherichia coli Population Toward Larger Multiple Drug Resistance Numbers.

Science.gov (United States)

Suhartono, Suhartono; Savin, Mary C; Gbur, Edward E

2018-04-01

Transmissible plasmids and integrons may play important roles in the persistence and spread of antibiotic-resistant bacteria throughout aquatic environment by accumulating antibiotic resistance genes (ARG). Class 1 and class 2 integron (intI), mobilization (mob), sulfamethoxazole resistance (sul), and trimethoprim resistance (dfr) genes were PCR-amplified and confirmed through DNA sequencing following plasmid extraction from 139 antibiotic-resistant Escherichia coli. E. coli had previously been recovered from wastewater treatment plant effluent and receiving stream water in Northwest Arkansas and isolates had expressed resistance to one to six antibiotics. Almost half of the total isolates (47%) carried putatively transmissible plasmids with mob F12 gene as the most frequently detected mobilization gene. When two or three mob genes were detected per isolate, there was a significant shift in the population toward larger multiple drug resistance (MDR) number. Class 1 and/or 2 integrons were prevalent (46%), and the presence of integron significantly shifted the isolate population toward larger MDR number. More isolates carried single or coexistence of two or three sul genes (99.3%), and single or a combination up to five dfr genes (89.3%) than had exhibited in vitro resistance to the respective antibiotics. These findings indicate not only the role of the wastewater treatment effluent and the stream environment in coaccumulation of ARG with transmissible plasmids and integrons in multiple antibiotic-resistant E. coli populations but also suggest that density of sul and dfr resistance genes within an isolate may serve as a biomarker for mobile MDR in general.

Born-Infeld magnetars: larger than classical toroidal magnetic fields and implications for gravitational-wave astronomy

Science.gov (United States)

Pereira, Jonas P.; Coelho, Jaziel G.; de Lima, Rafael C. R.

2018-05-01

Magnetars are neutron stars presenting bursts and outbursts of X- and soft-gamma rays that can be understood with the presence of very large magnetic fields. In this setting, nonlinear electrodynamics should be taken into account for a more accurate description of such compact systems. We study that in the context of ideal magnetohydrodynamics and make a realization of our analysis to the case of the well known Born-Infeld (BI) electromagnetism in order to come up with some of its astrophysical consequences. We focus here on toroidal magnetic fields as motivated by already known magnetars with low dipolar magnetic fields and their expected relevance in highly magnetized stars. We show that BI electrodynamics leads to larger toroidal magnetic fields when compared to Maxwell's electrodynamics. Hence, one should expect higher production of gravitational waves (GWs) and even more energetic giant flares from nonlinear stars. Given current constraints on BI's scale field, giant flare energetics and magnetic fields in magnetars, we also find that the maximum magnitude of magnetar ellipticities should be 10^{-6}-10^{-5}. Besides, BI electrodynamics may lead to a maximum increase of order 10-20% of the GW energy radiated from a magnetar when compared to Maxwell's, while much larger percentages may arise for other physically motivated scenarios. Thus, nonlinear theories of the electromagnetism might also be probed in the near future with the improvement of GW detectors.

Social thermoregulation as a potential mechanism linking sociality and fitness: Barbary macaques with more social partners form larger huddles.

Science.gov (United States)

Campbell, Liz A D; Tkaczynski, Patrick J; Lehmann, Julia; Mouna, Mohamed; Majolo, Bonaventura

2018-04-17

Individuals with more or stronger social bonds experience enhanced survival and reproduction in various species, though the mechanisms mediating these effects are unclear. Social thermoregulation is a common behaviour across many species which reduces cold stress exposure, body heat loss, and homeostatic energy costs, allowing greater energetic investment in growth, reproduction, and survival, with larger aggregations providing greater benefits. If more social individuals form larger thermoregulation aggregations due to having more potential partners, this would provide a direct link between sociality and fitness. We conducted the first test of this hypothesis by studying social relationships and winter sleeping huddles in wild Barbary macaques (Macaca sylvanus), wherein individuals with more social partners experience greater probability of winter survival. Precipitation and low temperature increased huddle sizes, supporting previous research that huddle size influences thermoregulation and energetics. Huddling relationships were predicted by social (grooming) relationships. Individuals with more social partners therefore formed larger huddles, suggesting reduced energy expenditure and exposure to environmental stressors than less social individuals, potentially explaining how sociality affects survival in this population. This is the first evidence that social thermoregulation may be a direct proximate mechanism by which increased sociality enhances fitness, which may be widely applicable across taxa.

Sudden cardiac death in dogs with remodeled hearts is associated with larger beat-to-beat variability of repolarization

DEFF Research Database (Denmark)

Thomsen, Morten Bækgaard; Truin, Michiel; van Opstal, Jurren M

2005-01-01

Increased proarrhythmia in dogs with chronic AV block (AVB) has been explained by ventricular remodeling causing a decrease in repolarization reserve. Beat-to-beat variability of repolarization (BVR) has been suggested to reflect repolarization reserve, in which high variability represents...... diminished reserve and larger propensity for repolarization-dependent ventricular arrhythmia. A subset of chronic AVB dogs (10%) suffers sudden cardiac death (SCD). With the assumption that repolarization defects constitute a potentially lethal proarrhythmic substrate, we hypothesized that BVR in SCD dogs...... are larger than in matched control chronic AVB dogs. From a population of 200 chronic AVB dogs, initially two groups were chosen retrospectively: 8 dogs that died suddenly (SCD) and 8 control dogs. Control dogs had a longer lifespan after AVB (10 to 18 weeks) than SCD dogs (5 to 10 weeks). All dogs had...

Larger right posterior parietal volume in action video game experts: a behavioral and voxel-based morphometry (VBM study.

Directory of Open Access Journals (Sweden)

Satoshi Tanaka

Full Text Available Recent studies suggest that action video game players exhibit superior performance in visuospatial cognitive tasks compared with non-game players. However, the neural basis underlying this visuospatial cognitive performance advantage remains largely unknown. The present human behavioral and imaging study compared gray matter volume in action video game experts and non-experts using structural magnetic resonance imaging and voxel-based morphometry analysis. The results revealed significantly larger gray matter volume in the right posterior parietal cortex in experts compared with non-experts. Furthermore, the larger gray matter volume in the right posterior parietal cortex significantly correlated with individual performance in a visual working memory task in experts. These results suggest that differences in brain structure may be linked to extensive video game play, leading to superior visuospatial cognitive performance in action video game experts.

Analysis of secondary coxarthrosis by three dimensional computed tomography

Energy Technology Data Exchange (ETDEWEB)

Hemmi, Osamu [Keio Univ., Tokyo (Japan). School of Medicine

1997-11-01

The majority of coxarthrosis in Japan is due to congenital dislocation of the hip and acetabular dysplasia. Until now coxarthrosis has been chiefly analyzed on the basis of anterior-posterior radiographs. By using three-dimensional (3D) CT, it was possible to analyze the morphological features of secondary coxarthrosis more accurately, and by using new computer graphics software, it was possible to display the contact area in the hip joint and observe changes associated with progression of the stages of the disease. There were 34 subjects (68 joints), and all of who were women. The CT data were read into a work station, and 3D reconstruction was achieved with hip surgery simulation software (SurgiPlan). Pelvic inclination, acetabular anteversion, seven parameters indicating the investment of the femoral head and two indicating the position of the hip joint in the pelvis were measured. The results showed that secondary coxarthrosis is characterized not only by lateral malposition of the hip joint according to the pelvic coordinates, but by anterior malposition as well. Many other measurements provided 3D information on the acetabular dysplasia. Many of them were correlated with the CE angle on plain radiographs. Furthermore, a strong correlation was not found between anterior and posterior acetabular coverage of the femoral head. In addition, SurgiPlan`s distance mapping function enabled 3D observation of the pattern of progression of arthrosis based on the pattern of progression of joint space narrowing. (author)

Supply and Demand Analysis of the Orthopaedic Trauma Surgeon Workforce in the United States.

Science.gov (United States)

Sielatycki, John A; Sawyer, Jeffrey R; Mir, Hassan R

2016-05-01

To investigate recent trends in the orthopaedic trauma workforce and to assess whether supply of orthopaedic trauma surgeons (OTS) matches the demand for their skills. Supply estimated using Orthopaedic Trauma Association (OTA) membership and American Academy of Orthopaedic Surgeons census data. The annual number of operative pelvic and acetabular fractures reported by American College of Surgeons verified trauma centers in the National Trauma Data Bank (NTDB) was used as a surrogate of demand. Because surrogates were used, the annual rate of change in OTA membership versus rate of change in operative injuries per NTDB center was compared. From 2002 to 2012, reported operative pelvic and acetabular injuries increased by an average of 21.0% per year. The number of reporting trauma centers increased by 27.2% per year. The number of OTA members increased each year except in 2009, with mean annual increase of 9.8%. The mean number of orthopaedic surgeons per NTDB center increased from 7.98 to 8.58, an average of 1.5% per year. The annual number of operative pelvic and acetabular fractures per NTDB center decreased from 27.1 in 2002 to 19.03 in 2012, down 2.0% per year. In the United States, from 2002 to 2012, the number of OTS trended upward, whereas operative pelvic and acetabular cases per reporting NTDB center declined. These trends suggest a net loss of such cases per OTS over this period.

Allogenic bone graft viability after hip revision arthroplasty assessed by dynamic [18F]fluoride ion positron emission tomography

International Nuclear Information System (INIS)

Piert, M.; Becker, H.D.; Winter, E.; Becker, G.A.; Bilger, K.; Machulla, H.J.; Mueller-Schauenburg, W.; Bares, R.

1999-01-01

The biological fate of allogenic bone grafts in the acetabular cavity and their metabolic activity after acetabular augmentation is uncertain but is most important for the stability of hip implants after hip revision arthroplasty. The aim of this study was to quantify regional bone metabolism after hip replacement operations. Dynamic [ 18 F]fluoride ion positron emission tomography (PET) was used to investigate the metabolic activity of acetabular allogenic bone grafts and genuine bone, either 3-6 weeks (short-term group, n = 9) or 5 months to 9 years (long-term group, n = 10) after hip revision arthroplasty. Applying a three-compartment model, the fluoride influx constant was calculated from individually fitted rate constants (K nlf ) and by Patlak graphical analysis (K pat ). The results were compared with genuine cancellous and cortical acetabular bone of contralateral hips without surgical trauma (n = 7). In genuine cortical bone, K nlf was significantly increased in short- (+140.9%) and long-term (+100.0%) groups compared with contralateral hips. Allogenic bone grafts were characterised by a significantly increased K nlf in the short-term group (+190.9%) compared with contralateral hips, but decreased almost to the baseline levels of contralateral hips (+45.5%) in the long-term. Values of K nlf cor-related with the rate constant K 1 in genuine (r = 0.89, P pat values were highly correlated with K nlf measurements in all regions. (orig.)

Analysis of secondary coxarthrosis by three dimensional computed tomography

International Nuclear Information System (INIS)

Hemmi, Osamu

1997-01-01

The majority of coxarthrosis in Japan is due to congenital dislocation of the hip and acetabular dysplasia. Until now coxarthrosis has been chiefly analyzed on the basis of anterior-posterior radiographs. By using three-dimensional (3D) CT, it was possible to analyze the morphological features of secondary coxarthrosis more accurately, and by using new computer graphics software, it was possible to display the contact area in the hip joint and observe changes associated with progression of the stages of the disease. There were 34 subjects (68 joints), and all of who were women. The CT data were read into a work station, and 3D reconstruction was achieved with hip surgery simulation software (SurgiPlan). Pelvic inclination, acetabular anteversion, seven parameters indicating the investment of the femoral head and two indicating the position of the hip joint in the pelvis were measured. The results showed that secondary coxarthrosis is characterized not only by lateral malposition of the hip joint according to the pelvic coordinates, but by anterior malposition as well. Many other measurements provided 3D information on the acetabular dysplasia. Many of them were correlated with the CE angle on plain radiographs. Furthermore, a strong correlation was not found between anterior and posterior acetabular coverage of the femoral head. In addition, SurgiPlan's distance mapping function enabled 3D observation of the pattern of progression of arthrosis based on the pattern of progression of joint space narrowing. (author)

Benign core biopsy of probably benign breast lesions 2 cm or larger: correlation with excisional biopsy and long-term follow-up

OpenAIRE

Jung, Hyun Kyung; Moon, Hee Jung; Kim, Min Jung; Kim, Eun-Kyung

2014-01-01

Purpose: To evaluate the accuracy of benign core biopsy of probably benign breast lesions (category 3) 2 cm or larger on the basis of excisional biopsy and long-term follow-up. Methods: We retrospectively reviewed 146 category 3 lesions in 146 patients 2 cm or larger which were diagnosed as benign by ultrasound (US)-guided core biopsy. Patients were initially diagnosed as benign at core needle biopsy and then followed up with excisional biopsy (surgical excision, n=91; US-guided vacuum assist...

Solar Sail Models and Test Measurements Correspondence for Validation Requirements Definition

Science.gov (United States)

Ewing, Anthony; Adams, Charles

2004-01-01

Solar sails are being developed as a mission-enabling technology in support of future NASA science missions. Current efforts have advanced solar sail technology sufficient to justify a flight validation program. A primary objective of this activity is to test and validate solar sail models that are currently under development so that they may be used with confidence in future science mission development (e.g., scalable to larger sails). Both system and model validation requirements must be defined early in the program to guide design cycles and to ensure that relevant and sufficient test data will be obtained to conduct model validation to the level required. A process of model identification, model input/output documentation, model sensitivity analyses, and test measurement correspondence is required so that decisions can be made to satisfy validation requirements within program constraints.

CT to delineate hip pathology in cerebral palsy

International Nuclear Information System (INIS)

Mahboubi, S.; Horstmann, H.

1987-01-01

Surgical intervention for cerebral palsy hip dislocation or subluxation is frequently undertaken without a full comprehension of the three-dimensional aspects of the femoral-acetabular complex. CT with a modified technique allows more accurate measurement of the angle of femoral anteversion. In this exhibit the authors compare the modified technique with the old technique. Details of femoral had deficits, acetabular configuration, the arc of the acetabulum, the relative position of the femoral head within the acetabulum, and the soft tissue interposed between the femoral head and the acetabulum are well demonstrated with the new technique

Protrusio acetabuli in sickle-cell anemia

International Nuclear Information System (INIS)

Martinez, S.; Apple, J.S.; Baber, C.; Putman, C.E.; Rosse, W.F.

1984-01-01

Of 155 adults with sickle-cell anemia (SS, SC), radiographs of the pelvis or hip demonstrated protrusio acetabuli on at least one side in 14 (3 men and 11 women), as indicated by projection of the acetabular line medial to the ilio-ischial line. All 14 patients had bone changes attributable to sickle-cell anemia, including marrow hyperplasia and osteonecrosis; however, the severity of femoral or acetabular osteonecrosis did not appear directly related to the protrusion. The authors conclude that sickle-cell anemia can predispose to development of protrusio acetabuli

Larger fig wasps are more careful about which figs to enter--with good reason.

Science.gov (United States)

Liu, Cong; Yang, Da-Rong; Compton, Stephen G; Peng, Yan-Qiong

2013-01-01

Floral longevity reflects a balance between gains in pollinator visitation and the costs of flower maintenance. Because rewards to pollinators change over time, older flowers may be less attractive, reducing the value of extended longevity. Un-pollinated figs, the inflorescences of Ficus species, can remain receptive for long periods, but figs that are older when entered by their host-specific fig wasp pollinators produce fewer seeds and fig wasp offspring. Our field experiments with Ficushispida, a dioecious fig tree, examined how the length of time that receptive figs have remained un-pollinated influences the behaviour and reproductive success of its short-lived fig wasp pollinator, Ceratosolensolmsi marchali. The results were consistent in three different seasons, and on male and female trees, although receptivity was greatly extended during colder months. Pollinators took longer to find the ostioles of older figs, and longer to penetrate them. They also became increasingly unwilling to enter figs as they aged, and increasing numbers of the wasps became trapped in the ostiolar bracts. Larger individuals were particularly unwilling to enter older figs, resulting in older figs being pollinated by smaller wasps. On female trees, where figs produce only seeds, seed production declined rapidly with fig age. On male trees, the numbers and size of fig wasp offspring declined, and a higher proportion were male. Older male figs are harder to enter, especially for larger individuals, and offer poorer quality oviposition opportunities. This study opens an interesting new perspective on the coevolution of figs and their pollinators, especially factors influencing pollinator body size and emphasises the subtleties of interactions between mutualists.

MASSIVE GALAXIES ARE LARGER IN DENSE ENVIRONMENTS: ENVIRONMENTAL DEPENDENCE OF MASS–SIZE RELATION OF EARLY-TYPE GALAXIES

Energy Technology Data Exchange (ETDEWEB)

Yoon, Yongmin; Im, Myungshin; Kim, Jae-Woo, E-mail: yymx2@astro.snu.ac.kr, E-mail: mim@astro.snu.ac.kr [Center for the Exploration of the Origin of the Universe (CEOU), Astronomy Program, Department of Physics and Astronomy, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul, 151-742 (Korea, Republic of)

2017-01-01

Under the Λ cold dark matter (ΛCDM) cosmological models, massive galaxies are expected to be larger in denser environments through frequent hierarchical mergers with other galaxies. Yet, observational studies of low-redshift early-type galaxies have shown no such trend, standing as a puzzle to solve during the past decade. We analyzed 73,116 early-type galaxies at 0.1 ≤  z  < 0.15, adopting a robust nonparametric size measurement technique and extending the analysis to many massive galaxies. We find for the first time that local early-type galaxies heavier than 10{sup 11.2} M {sub ⊙} show a clear environmental dependence in mass–size relation, in such a way that galaxies are as much as 20%–40% larger in the densest environments than in underdense environments. Splitting the sample into the brightest cluster galaxies (BCGs) and non-BCGs does not affect the result. This result agrees with the ΛCDM cosmological simulations and suggests that mergers played a significant role in the growth of massive galaxies in dense environments as expected in theory.

Males that drop a sexually selected weapon grow larger testes.

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Joseph, Paul N; Emberts, Zachary; Sasson, Daniel A; Miller, Christine W

2018-01-01

Costly sexually selected weapons are predicted to trade off with postcopulatory traits, such as testes. Although weapons can be important for achieving access to females, individuals of some species can permanently drop (i.e. autotomize) their weapons, without regeneration, to escape danger. We capitalized on this natural behavior to experimentally address whether the loss of a sexually selected weapon leads to increased testes investment in the leaf-footed cactus bug, Narnia femorata Stål (Hemiptera: Coreidae). In a second experiment, we measured offspring production for males that lost a weapon during development. As predicted, males that dropped a hind limb during development grew significantly larger testes than the control treatments. Hind-limb autotomy did not result in the enlargement of other nearby traits. Our results are the first to experimentally demonstrate that males compensate for natural weapon loss by investing more in testes. In a second experiment we found that females paired with males that lost a hind limb had 40% lower egg hatching success than females paired with intact males, perhaps because of lower mating receptivity to males with a lost limb. Importantly, in those cases where viable offspring were produced, males missing a hind limb produced 42% more offspring than males with intact limbs. These results suggest that the loss of a hind-limb weapon can, in some cases, lead to greater fertilization success. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

The effect of motion patterns on edge-loading of metal-on-metal hip resurfacing.

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Mellon, S J; Kwon, Y-M; Glyn-Jones, S; Murray, D W; Gill, H S

2011-12-01

The occurrence of pseudotumours (soft tissue masses relating to the hip joint) following metal-on-metal hip resurfacing arthroplasty (MoMHRA) has been associated with high serum metal ion levels and consequently higher than normal bearing wear. We investigated the relationship between serum metal ion levels and contact stress on the acetabular component of MoMHRA patients for two functional activities; gait and stair descent. Four subjects with MoMHRA, who had their serum metal ion levels measured, underwent motion analysis followed by CT scanning. Their motion capture data was combined with published hip contact forces and finite element models representing 14% (peak force) and 60% (end of stance) of the gait cycle and 52% (peak force) of stair descent activity were created. The inclination angle of the acetabular component was increased by 10° in 1° intervals and the contact stresses were determined at each interval for each subject. When the inclination angle was altered in such a way as to cause the hip contact force to pass through the edge of the acetabular component edge-loading occurred. Edge-loading increased the contact stress by at least 50%; the maximum increase was 108%. Patients with low serum metal ion levels showed no increase in contact stress at peak force during gait or stair descent. Patients with high serum metal ion levels exhibited edge-loading with an increase to the inclination angle of their acetabular components. The increase in inclination angle that induced edge-loading for these subjects was less than the inter-subject variability in the angle of published hip contact forces. The results of this study suggest that high serum metal ion levels are the result of inclination angle influenced edge-loading but that edge-loading cannot be attributed to inclination angle alone and that an individual's activity patterns can reduce or even override the influence of a steep acetabular component and prevent edge-loading. Copyright © 2011 IPEM

Integro-differential equation approach extended to larger nuclei

International Nuclear Information System (INIS)

Adam, R.M.; Sofianos, S.A.; Fiedeldey, H.; Fabre de la Ripelle, M.

1992-01-01

We extend the integro-differential equation approach (IDEA) from few-nucleon to closed-shell and closed-subshell nuclei and outline the analytical methods required for the calculation of the density functions, which enter into the integro-differential equations. These contain all the physics for a system of fermions associated with the Pauli principle. In order to test the accuracy of the IDEA comparisons are made of the binding energies of 4 He, 12 C and 16 O obtained with effective potentials using the hypercentral approximation (HCA) providing a variational solution without correlations, the IDEA which fully includes the two-body correlations, the S-states integro-differential equation (SIDE) valid for potentials operating only on pairs in the S-state and those calculated by several variational or perturbative methods in the literature. (author)

Protocol for CT in the position of discomfort: preoperative assessment of femoroacetabular impingement - how we do it and what the surgeon wants to know

International Nuclear Information System (INIS)

Grabinski, Rafal; Ou, Daniel; Saunder, Kate; Rotstein, Andrew; Singh, Parminder; Pritchard, Michael; O'Donnell, John

2014-01-01

The use of computed tomography of the hip in a position of discomfort (CT-POD) in combination with 2D and 3D surface rendering is a technique increasingly used to aid in the assessment and confirmation of femoral and acetabular bony abnormalities related to femoroacetabular impingement. The purpose of this article is to describe this dynamic method of assessment. Patients referred by orthopaedic surgeons for assessment of femoroacetabular impingement as part of preoperative planning and patients who required postoperative assessment of residual bony abnormalities were selected. This article describes the CT-POD technique and the information required by the referring surgeon. CT-POD is a new technique that provides valuable preoperative and postoperative information to the surgeon.

Effect of high dietary copper on growth, antioxidant and lipid metabolism enzymes of juvenile larger yellow croaker Larimichthys croceus

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Fanxing Meng

2016-05-01

Full Text Available A study was carried out to test the responses of juvenile larger yellow croaker Larimichthys croceus to high Cu intake. Experimental diets were formulated containing three levels of Cu: low Cu (3.67 mg/kg, middle Cu (13.65 mg/kg and high Cu (25.78 mg/kg, and each diet were fed to large yellow croaker in triplicate for 10 weeks. Final body weight, weight gain and feed intake were the lowest in high Cu group, but hepatosomatic index was the highest; Cu concentrations in the whole-body, muscle and liver of fish fed low Cu diet was the lowest; Liver superoxide dismutase, catalase and glutathione peroxidase activities in fish fed high Cu diet were lower than those in fish fed other diets; The higher content of liver thiobarbituric acid reactive substance content was found in high Cu group, followed by middle Cu group, and the lowest in low Cu group; Liver 6-phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase, malic enzyme, isocitrate dehydrogenase and fatty acid synthase activities were the lowest in high Cu group, but lipoprotein lipase activity was the highest. This study indicated that high copper intake reduced growth of juvenile larger yellow croaker, inhibited activities of antioxidant enzymes and lipid synthetases, and led to energy mobilization. Keywords: Larger yellow croaker, Copper, Antioxidant enzyme, Lipid metabolism enzyme

[The Use of Jumbo Cups in Revision Total Hip Arthroplasty].

Science.gov (United States)

von Roth, Philipp; Wassilew, Georgi I

2017-10-01

Extra-large uncemented jumbo cups are among the most common methods of acetabular revision. Jumbo cups do not contribute to bone stock restoration, and in the case of a subsequent revision, an even larger bone defect is to be expected. Thus, understanding long-term survival is essential. The present article discusses the literature relevant to this topic and addresses technical and implant-specific characteristics of jumbo cups. In summary, jumbo cups show an acceptable long-term survival rate, with aseptic loosening as the most common reason for revision and dislocation being the most common complication. Through the development of alternative revision systems, jumbo cups have lost their importance in today's practice. However, they can serve as a benchmark for studies of newer technologies in revision total hip arthroplasty. Georg Thieme Verlag KG Stuttgart · New York.

Application of chemical mutagens and radiation in breeding buckwheat for larger seeds

International Nuclear Information System (INIS)

Alekseeva, E.S.

1988-01-01

Full text: In 1974, seeds of the Viktoriya variety of buckwheat were treated with 20-30 krad gamma radiation and chemical mutagens in the Biophysics Department of the Kishinev Agricultural Institute. For the chemical mutagen treatment, we used N-ethylnitroso-urea NEH (0.025 and 0.012%), N-methylnitroso-urea NMH (0.01 and 0.005%), ethylenimine EI (0.01 and 0.005%), dimethyl sulphate DMS (0.01 and 0.005%) and 1.4-bis-diazoacetyl butane DAB (0.01 and 0.05%). Since some investigators think that different results are produced by changing the order of the treatment, we treated seeds with chemical mutagens before and after irradiation and this was followed by drying. A total of 2400 seeds were treated. Selection started with M 2 seeds produced by M 1 plants. The thousand seed weight of the best ones ranged from 40.7 to 47.8 g, which was 11.9-18.7 g heavier than the control. The large seed size thus selected was heritable. Since larger seeds are very important for the creation of high yielding varieties buckwheat, only families with these characteristics were selected for further work. We observed even some further increase in seed weight in the next generation. It was observed that when planting large seeds, after six days of growth the cotyledons were significantly larger than in the control plants. This characteristic was used in selecting for a high yielding large-seed variety of buckwheat. The plants were selected twice: once for development of large cotyledon leaves and the second time for plant yield. In the fourth generation, the families thus obtained continued to be studied in greenhouse experiments and the same time be propagated under field conditions. The seeds of these families were then combined and under the name Podolyanka in 1976 were subjected to competitive variety testing. Following the competitive variety testing the mutant variety Podolyanka was released in 1984. It is high yielding (2950 kg/ha), has a short vegetation period (matures 17-18 days

Electrofishing power requirements in relation to duty cycle

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Miranda, L.E.; Dolan, C.R.

2004-01-01

Under controlled laboratory conditions we measured the electrical peak power required to immobilize (i.e., narcotize or tetanize) fish of various species and sizes with duty cycles (i.e., percentage of time a field is energized) ranging from 1.5% to 100%. Electrofishing effectiveness was closely associated with duty cycle. Duty cycles of 10-50% required the least peak power to immobilize fish; peak power requirements increased gradually above 50% duty cycle and sharply below 10%. Small duty cycles can increase field strength by making possible higher instantaneous peak voltages that allow the threshold power needed to immobilize fish to radiate farther away from the electrodes. Therefore, operating within the 10-50% range of duty cycles would allow a larger radius of immobilization action than operating with higher duty cycles. This 10-50% range of duty cycles also coincided with some of the highest margins of difference between the electrical power required to narcotize and that required to tetanize fish. This observation is worthy of note because proper use of duty cycle could help reduce the mortality associated with tetany documented by some authors. Although electrofishing with intermediate duty cycles can potentially increase effectiveness of electrofishing, our results suggest that immobilization response is not fully accounted for by duty cycle because of a potential interaction between pulse frequency and duration that requires further investigation.

Changes of the hip joints associated with chronic subluxation and dislocation: CT and plain radiography analysis

International Nuclear Information System (INIS)

Yang, Ik; Ryu, Kyung Nam; Lee, Sun Wha; Choi, Woo Suk; Lee, Eil Seong

1993-01-01

Secondary osteoarthritis of the hip joint is a common disease and is frequently followed by chronic subluxation and dislocation. Twenty four cases of the secondary osteoarthritis associated with chronic subluxation and dislocation of the hip joints were evaluated with plain radiography and computed tomography. We retrospectively analyzed 1) the osteoarthritis and calcification of the acetabular labrum, 2) the thickness of the quadrilateral plate of the ilium, and 3) anteroposterior diameter of the acetabulum. The changes of the hip joints in subluxation (n=14) revealed ossification of the acetabular labrum in 12 cases (86%), thickening of the quadrilateral plate of the ilium in 11 cases (78%) but anteroposterior diameter of the acetabulum was not changed. The changes of the hip joints in dislocation (n=10) revealed no evidence of the ossification of the acetabular labrum, thickening of the quadrilateral plate of the ilium in 10 cases (100%) and decreased anteroposterior diameter of the acetabulum. We conclude that CT findings of subluxation and dislocation of the hip joints can be helpful in the evaluation of the secondary osteoarthritis of the hip joints

Fracture of the acetabulum with femoral artery injury presenting late: A case report

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Sivaprasad Kalyanasundaram

2016-02-01

Full Text Available This study reports a rare case of both column acetabulum fracture with femoral artery injury that presented late and was managed with arterial reconstruction and fracture fixation.A thirty-one year old man sustained both column acetabular fracture on the left in a motor vehicle accident. On admission there was no obvious neuro-vascular deficit. During surgery for the fracture after 7 days of the injury the femoral artery was found to be severely crushed with no blood flow. The anterior column of the acetabulum was stabilised followed by resection and reconstruction of the femoral artery. The post-operative period was uneventful and he was discharged normally. At 6 months from injury the fractures had united well with excellent limb circulation and good lower limb function.Femoral artery injury with acetabular fracture is rare and late presentations are unreported hitherto. The results of fracture stabilisation and vessel reconstruction seem to be excellent. Literature of similar injuries is reviewed. Keywords: Acetabular fractures, Both column fractures, Anterior column fractures, Vascular injury, Femoral artery injury

Connecting West Virginia fee-fishing businesses with the larger tourism market through the development of tourism package

Science.gov (United States)

Zongxiang Mei; Chad Pierskalla; Michael Shuett

2007-01-01

Thirty-five or more fee-fishing businesses in West Virginia are often characterized as small businesses, and they could benefit from connecting with larger travel packages that are more likely to attract out-of state anglers. The objectives of this study are to: (1) identify mini-market segments based on fee-fishing experiences; (2) examine how fee-fishing mini-markets...

Fate of bulk auto grafts in uncemented total hip arthroplasty: Evaluation by bone scintigraphy

International Nuclear Information System (INIS)

Simsek, A.; Cila, E.; Sener, E.; Senkoylu, A.; Sipahioglu, S.; Atasever, T.; Akdemir, Ozgur

2006-01-01

Objective was to review short term results of uncemented cup implantation and the fate of bulk femoral head autografts in patients with acetabular bone deficiency due to dysplasia of the hip. We used bone scintigraphy to assess the viability of the grafts. We treated 19 hip joints of 17 patients with osteoarthritis due to developmental dysplasia of the hip with uncemented total hip arthroplasty between 1997-2003 in the Department of Orthopedics and Traumatology, Gazi University, Ankara, Turkey. The average age was 49.1 (31-72 years), and the average follow up period was 36 months. We used femoral head autografts to reconstruct superolateral segmental deficiencies of the acetabuli. We evaluated the patients clinically and radiologically to assess acetabular loosening, and we used three-phase bone scintigraphy to evaluate the viability of the autograft.There was no acetabular component revision throughout the follow up period. There was no radiological evidence of graft resorption or graft displacement in any of the patients. In bone scintigraphy, we observed hyperemia in the blood pool phase, and the osteoblastic activity of the bone graft was at the level of the neighboring iliac bone. The application of a non-cemented acetabular component with femoral autograft in superolateral acetabulum deficiency increases the stability of the implant and increases the bone stock. It is not easy to evaluate the viability of the graft by the use of radiological methods. Bone scintigraphy gives sufficient information about the viability of the graft as a non-invasive method. (author)

R3 Cup Does Not Have a High Failure Rate in Conventional Bearings: A Minimum of 5-Year Follow-Up.

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Teoh, Kar H; Whitham, Robert D J; Golding, David M; Wong, Jenny F; Lee, Paul Y F; Evans, Aled R

2018-02-01

The R3 cementless acetabular system was first marketed in Australia and Europe in 2007. Previous papers have shown high failure rates of the R3 cup with up to 24% with metal-on-metal bearing. There are currently no medium term clinical results on this cup. The aim of the study is to review our results of the R3 acetabular cup with conventional bearings with a minimum of 5-year follow-up. Patients who were implanted with the R3 acetabular cup were identified from our center's arthroplasty database. A total of 293 consecutive total hip arthroplasties were performed in 286 patients. The primary outcome was revision. The secondary outcomes were the Oxford Hip Scores (OHS) and radiographic evaluation. The mean age of the patients was 69.4 years. The mean preoperative OHS was 23 (range 10-34) and the mean OHS was 40 (range 33-48) at the final follow-up. Radiological evaluation showed an excellent ARA score in all patients at 5 years. None of the R3 cups showed osteolysis at the final follow-up. There were 3 revisions in our series, of which 2 R3 cups were revised. The risk of revision was 1.11% at 5 years. Our experience of using the R3 acetabular system with conventional bearings showed high survivorship and is consistent with the allocated Orthopaedic Data Evaluation Panel rating of 5A* as rated in 2015 in the United Kingdom. Copyright © 2017 Elsevier Inc. All rights reserved.

Colour doppler ultrasound assessment of the normal neonatal hip

International Nuclear Information System (INIS)

Ortiz-Neira, C.L.; Laffan, E.; Daneman, A.; Fong, K.; Roposch, A.

2009-01-01

To determine the morphology and hemodynamic characteristics of the arterial vessels of the proximal femur according to specific anatomic regions in asymptomatic neonates in 2 pediatric-based health care institutions. Forty-three neonates (29 female, 14 male; age range, 2 d-3 mo; median age, 3 d) were enrolled in the study. Thirty-two (37%) of 86 hips were classified as Graf type IIA joints (mean alpha angle, 56.0 o ± 2.7 o ), and 54 (63%) were classified as type I joints (mean alpha angle, 65.0 o ± 4.6 o ). Colour and spectral Doppler imaging identified vessels running along the acetabular labrum, epiphyseal vessels, and femoral neck. We showed 4 different patterns of vascularity of the hips: radial, parallel, mixed radial-parallel, and indeterminate, however, they were not related to the hip maturity (P = .3, coronal plane; P = .62, transverse plane) or to the amount of colour pixels identified in each region (P = .35). The mean number of pixels in the ligamentum teres region was significantly higher than that in other regions of interest (P =.03). Except for the acetabular labrum arteries, Doppler spectrum waveforms of proximal femur arteries presented with low resistivity. There was a tendency towards females' acetabular arteries presenting with lower peak systolic velocities than males' acetabular arteries (P =.06). Colour Doppler spectrum waveforms and intensity of vascularity in normal neonatal hips differ according to the anatomic region under evaluation. This observation deserves further investigation on its role on the physiopathogenesis of neonatal hip disorders. (author)

Biological control agent of larger black flour beetles (Coleoptera: Tenebrionidae): A nuisance pest developing in cotton gin trash piles.

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Larger black flour beetles (LBFB), Cynaeus angustus, feed on saprophytic fungi found in gin trash piles, and become nuisance pests in homes and businesses. We examined the dose-response of three entomopathogenic nematode species (Steinernema carpocapsae, S. feltiae, and Heterorhabditis bacteriophora...

Fracturing of revision of a cobalt-chrome femoral head after fracturing of a ceramic femoral head, with diffuse metallosis. Case report

Directory of Open Access Journals (Sweden)

Pedro Miguel Dantas Costa Marques

2013-04-01

Full Text Available We presente a case of a fracture of a cobalt-chrome femoral head after revision of a hip total prosthesis with ceramic femoral head fracture. During surgery we found the cobalt-chrome femoral head fracture, wear of the polyethylene and massive metallosis in muscular and cartilaginous tissue. Both femoral stem and acetabular cup were stable and without apparent wearing. After surgical debridement, we promoted the substitution of the femoral head and the acetabular polyethylene by similar ones. After 12 months of follow-up, the patient has no pain complaints, function limit or systemic signs associated with malign metallosis

Hip dysplasia in the cat: a report of three cases

International Nuclear Information System (INIS)

Patsikas, M.N.; Papazoglou, L.G.; Komninou, A.; Dessiris, A.K.; Tsimopoulos, G.

1998-01-01

Hip dysplasia was diagnosed in three cats. Two were presented with a history of hindlimb lameness and the other had a history of constipation. All were confined for two weeks and showed considerable clinical improvement. At follow-up examination the cats were free of clinical signs despite the deterioration in the radiological appearance of their hips. Luxation or subluxation of the hips, insufficient development of the craniolateral acetabular edges, loss of the arched shape of the cranial subchondral acetabular bones, shallow acetabula and secondary degenerative changes on the femoral heads and necks were the main radiological findings in the affected cats

Increased migration of uncemented acetabular cups in female total hip arthroplasty patients with low systemic bone mineral density. A 2-year RSA and 8-year radiographic follow-up study of 34 patients.

Science.gov (United States)

Finnilä, Sami; Moritz, Niko; SvedströM, Erkki; Alm, Jessica J; Aro, Hannu T

2016-02-01

Low bone mineral density (BMD) may jeopardize the initial component stability and delay osseointegration of uncemented acetabular cups in total hip arthroplasty (THA). We measured the migration of uncemented cups in women with low or normal BMD. We used radiostereometric analysis (RSA) to measure the migration of hydroxyapatite-coated titanium alloy cups with alumina-on-alumina bearings in THA of 34 female patients with a median age of 64 (41-78) years. 10 patients had normal BMD and 24 patients had low systemic BMD (T-score ≤ -1) based on dual-energy X-ray absorptiometry (DXA). Cup migration was followed with RSA for 2 years. Radiographic follow-up was done at a median of 8 (2-10) years. Patients with normal BMD did not show a statistically significant cup migration after the settling period of 3 months, while patients with low BMD had a continuous proximal migration between 3 and 12 months (p = 0.03). These differences in cup migration persisted at 24 months. Based on the perceived risk of cup revision, 14 of the 24 cases were "at risk" (proximal translation of 0.2 to 1.0 mm) in the low-BMD group and 2 of the 10 cases were "at risk" in the normal-BMD group (odds ratio (OR) = 8.0, 95% CI: 1.3-48). The radiographic follow-up showed no radiolucent lines or osteolysis. 2 cups have been revised for fractures of the ceramic bearings, but none for loosening. Low BMD contributed to cup migration beyond the settling period of 3 months, but the migrating cups appeared to osseointegrate eventually.

Mid-Eocene (Bartonian) larger benthic foraminifera from southeastern Turkey and northeastern Egypt: New evidence for the palaeobiogeography of the Tethyan carbonate platforms

Science.gov (United States)

Sallam, Emad S.; Erdem, Nazire Özgen; Sinanoğlu, Derya; Ruban, Dmitry A.

2018-05-01

Larger benthic foraminiferal assemblages from the mid-Eocene (Bartonian) sedimentary successions of the Tethyan carbonate platforms have been studied in southeastern Turkey and northeastern Egypt. In the Hazro-Diyarbakir section (SE Turkey), small-medium miliolids and textularinids are identified from the lower intervals of the Hoya Formation, whereas alveolinids and soritids (porcellaneous) and orbitolinids (agglutinated) increase in diversity and abundance in the upper intervals. The Dictyoconus aegyptiensis (Chapman) and Somalina stefaninii Silvestri are recorded for the first time from the Hoya Formation. The larger benthic foraminiferal assemblage from the Hoya Formation shows a significant similarity to those reported from the Observatory Formation (coeval with the Sannor Formation) in the Cairo-Suez district (NE Egypt). The studied foraminiferal assemblages imply restricted lagoonal-tidal flat palaeoenvironments. Palaeobiogeographically, the larger benthic foraminiferal assemblages recorded in southeastern Turkey and northeastern Egypt carbonate platforms display a strong affinity to the Arabian, Middle East and African platforms. The position of the global sea-level and the plate tectonic organization of the studied region during the Bartonian were the main factors that facilitated faunal exchange within the carbonate platforms.

Smoking Topography among Korean Smokers: Intensive Smoking Behavior with Larger Puff Volume and Shorter Interpuff Interval.

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Kim, Sungroul; Yu, Sol

2018-05-18

The difference of smoker's topography has been found to be a function many factors, including sex, personality, nicotine yield, cigarette type (i.e., flavored versus non-flavored) and ethnicity. We evaluated the puffing behaviors of Korean smokers and its association with smoking-related biomarker levels. A sample of 300 participants was randomly recruited from metropolitan areas in South Korea. Topography measures during a 24-hour period were obtained using a CReSS pocket device. Korean male smokers smoked two puffs less per cigarette compared to female smokers (15.0 (13.0⁻19.0) vs. 17.5 (15.0⁻21.0) as the median (Interquartile range)), but had a significantly larger puff volume (62.7 (52.7⁻75.5) mL vs. 53.5 (42.0⁻64.2) mL); p = 0.012). The interpuff interval was similar between men and women (8.9 (6.5⁻11.2) s vs. 8.3 (6.2⁻11.0) s; p = 0.122) but much shorter than other study results. A dose-response association ( p = 0.0011) was observed between daily total puff volumes and urinary cotinine concentrations, after controlling for sex, age, household income level and nicotine addiction level. An understanding of the difference of topography measures, particularly the larger puff volume and shorter interpuff interval of Korean smokers, may help to overcome a potential underestimation of internal doses of hazardous byproducts of smoking.

Assignment methodology for larger RNA oligonucleotides: Application to an ATP-binding RNA aptamer

International Nuclear Information System (INIS)

Dieckmann, Thorsten; Feigon, Juli

1997-01-01

The use of uniform 13C, 15N labeling in the NMR spectroscopic study of RNA structures has greatly facilitated the assignment process in small RNA oligonucleotides. For ribose spinsystem assignments, exploitation of these labels has followed previously developed methods for the study of proteins. However, for sequential assignment of the exchangeable and nonexchangeable protons of the nucleotides, it has been necessary to develop a variety of new NMR experiments. Even these are of limited utility in the unambiguous assignment of larger RNAs due to the short carbon relaxation times and extensive spectral overlap for all nuclei.These problems can largely be overcome by the additional use of base-type selectively 13C, 15N-labeled RNA in combination with a judicious use of related RNAs with base substitutions. We report the application of this approach to a 36-nucleotide ATP-binding RNA aptamer in complex with AMP. Complete sequential 1H assignments, as well as the majority of 13C and 15N assignments, were obtained

Performance of large-R jets and jet substructure reconstruction with the ATLAS detector

CERN Document Server

The ATLAS collaboration

2012-01-01

This paper presents the application of techniques to study jet substructure. The performance of modified jet algorithms for a variety of jet types and event topologies is investigated. Properties of jets subjected to the mass-drop filtering, trimming and pruning algorithms are found to have a reduced sensitivity to multiple proton-proton interactions and exhibit improved stability at high luminosity. Monte Carlo studies of the signal-background discrimination with jet grooming in new physics searches based on jet invariant mass and jet substructure properties are also presented. The application of jet trimming is shown to improve the robustness of large-R jet measurements, reduce sensitivity to the superfluous effects due to the intense environment of the high luminosity LHC, and improve the physics potential of searches for heavy boosted objects. The analyses presented in this note use the full 2011 ATLAS dataset, corresponding to an integrated luminosity of 4.7 \\pm 0.2 fb−1 .

Distribution of living larger benthic foraminifera in littoral environments of the United Arab Emirates

Science.gov (United States)

Fiorini, Flavia; Lokier, Stephen W.

2015-04-01

The distribution of larger benthic foraminifera in Recent littoral environment of the United Arab Emirates (Abu Dhabi and Western regions) was investigated with the aim of understanding the response of those foraminifera to an increase in water salinity. For this purpose, 100 sediment samples from nearshore shelf, beach-front, channel, lagoon, and intertidal environment were collected. Sampling was undertaken at a water depth shallower than 15 m in water with a temperature of 22 to 35˚C, a salinity ranging from 40 to 60‰ and a pH of 8. Samples were stained with rose Bengal at the moment of sample collection in order to identify living specimens. The most abundant epiphytic larger benthic foraminifera in the studied area were Peneroplis pertusus and P. planatus with less common Spirolina areatina, S. aciculate and Sorites marginalis. The living specimens of the above mentioned species with normal test growing were particularly abundant in the nearshore shelf and lagoonal samples collected on seaweed. Dead specimens were concentrated in the coarser sediments of the beach-front, probably transported from nearby environments. Shallow coastal ponds are located in the upper intertidal zone and have a maximum salinity of 60‰ and contain abundant detached seagrass. Samples collected from these ponds possess a living foraminifera assemblage dominated by Peneroplis pertusus and P. planatus. High percentages (up to 50% of the stained assemblage) of Peneroplis presented abnormality in test growth, such as the presence of multiple apertures with reduced size, deformation in the general shape of the test, irregular suture lines and abnormal coiling. The high percentage of abnormal tests reflects natural environmental stress mainly caused by high and variable salinity. The unique presence of living epiphytic species, suggests that epiphytic foraminifera may be transported into the pond together with seagrass and continued to live in the pond. This hypothesis is supported by

The 'Natural Laboratory', a tool for deciphering growth, lifetime and population dynamics in larger benthic foraminifera

Science.gov (United States)

Hohenegger, Johann

2015-04-01

The shells of symbiont-bearing larger benthic Foraminifera (LBF) represent the response to physiological requirements in dependence of environmental conditions. All compartments of the shell such as chambers and chamberlets accommodate the growth of the cell protoplasm and are adaptations for housing photosymbiotic algae. Investigations on the biology of LBF were predominantly based on laboratory studies. The lifetime of LBF under natural conditions is still unclear. LBF, which can build >100 chambers during their lifetime, are thought to live at least one year under natural conditions. This is supported by studies on population dynamics of eulittoral foraminifera. In species characterized by a time-restricted single reproduction period the mean size of specimens increases from small to large during lifetime simultaneously reducing individual number. This becomes more complex when two or more reproduction times are present within a one-year cycle leading to a mixture of abundant small individuals with few large specimens during the year, while keeping mean size more or less constant. This mixture is typical for most sublittoral megalospheric (gamonts or schizonts) LBF. Nothing is known on the lifetime of agamonts, the diploid asexually reproducing generation. In all hyaline LBF it is thought to be significantly longer than 1 year based on the large size and considering the mean chamber building rate of the gamont/schizonts. Observations on LBF under natural conditions have not been performed yet in the deeper sublittoral. This reflects the difficulties due to intense hydrodynamics that hinder deploying technical equipment for studies in the natural environment. Therefore, studying growth, lifetime and reproduction of sublittoral LBF under natural conditions can be performed using the so-called 'natural laboratory' in comparison with laboratory investigations. The best sampling method in the upper sublittoral from 5 to 70 m depth is by SCUBA diving. Irregular

Benign core biopsy of probably benign breast lesions 2 cm or larger: correlation with excisional biopsy and long-term follow-up

International Nuclear Information System (INIS)

Jung, Hyun Kyung; Moon, Hee Jung; Kim, Min Jung; Kim, Eun Kyung

2014-01-01

To evaluate the accuracy of benign core biopsy of probably benign breast lesions (category 3) 2 cm or larger on the basis of excisional biopsy and long-term follow-up. We retrospectively reviewed 146 category 3 lesions in 146 patients 2 cm or larger which were diagnosed as benign by ultrasound (US)-guided core biopsy. Patients were initially diagnosed as benign at core needle biopsy and then followed up with excisional biopsy (surgical excision, n=91; US-guided vacuum assisted excision, n=35) or breast ultrasonography (n=20). Of the 126 patients who underwent surgical excision or US-guided vacuum-assisted excision, 114 patients were diagnosed with benign lesions, 10 patients with borderline lesions (benign phyllodes tumor), and two patients with malignant phyllodes tumors. The probabilities of lesions being benign, borderline and malignant were 91.8% (134/146), 6.8% (10/146), and 1.4% (2/146), respectively. Of 13 patients who had growing masses on follow-up ultrasonography, three (23.1%) were non-benign (two benign phyllodes tumors and one malignant phyllodes tumor). US-guided core needle biopsy of probably benign breast mass 2 cm or larger was accurate (98.6%) enough to rule out malignancy. But, it was difficult to rule out borderline lesions even when they were diagnosed as benign.

In vivo toxicologic study of larger silica nanoparticles in mice

Directory of Open Access Journals (Sweden)

Chan WT

2017-04-01

Full Text Available Wai-Tao Chan,1–3 Cheng-Che Liu,4 Jen-Shiu Chiang Chiau,5 Shang-Ting Tsai,6 Chih-Kai Liang,6 Mei-Lien Cheng,5 Hung-Chang Lee,7,8 Chun-Yun Yeung,1,3,9 Shao-Yi Hou2,6 1Department of Pediatric Gastroenterology, Hepatology and Nutrition, MacKay Children’s Hospital, 2Graduate Institute of Engineering Technology, National Taipei University of Technology, 3Mackay Medicine, Nursing, and Management College, 4Institute of Preventive Medicine, National Defense Medical Center, Taipei, 5Department of Medical Research, MacKay Memorial Hospital, Hsinchu, 6Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of Technology, Taipei, 7Department of Pediatrics, MacKay Memorial Hospital, Hsinchu, 8Department of Pediatrics, Taipei Medical University, Taipei, 9Department of Medicine, Mackay Medical College, New Taipei, Taiwan, Republic of China Abstract: Silica nanoparticles (SiNPs are being studied and used for medical purposes. As nanotechnology grows rapidly, its biosafety and toxicity have frequently raised concerns. However, diverse results have been reported about the safety of SiNPs; several studies reported that smaller particles might exhibit toxic effects to some cell lines, and larger particles of 100 nm were reported to be genotoxic to the cocultured cells. Here, we investigated the in vivo toxicity of SiNPs of 150 nm in various dosages via intravenous administration in mice. The mice were observed for 14 days before blood examination and histopathological assay. All the mice survived and behaved normally after the administration of nanoparticles. No significant weight change was noted. Blood examinations showed no definite systemic dysfunction of organ systems. Histopathological studies of vital organs confirmed no SiNP-related adverse effects. We concluded that 150 nm SiNPs were biocompatible and safe for in vivo use in mice. Keywords: in vivo, mice, silica nanoparticle, nanotoxicity

Standby battery requirements for telecommunications power

Energy Technology Data Exchange (ETDEWEB)

May, G.J. [The Focus Partnership, 126 Main Street, Swithland, Loughborough, Leics LE12 8TJ (United Kingdom)

2006-08-25

The requirements for standby power for telecommunications are changing as the network moves from conventional systems to Internet Protocol (IP) telephony. These new systems require higher power levels closer to the user but the level of availability and reliability cannot be compromised if the network is to provide service in the event of a failure of the public utility. Many parts of these new networks are ac rather than dc powered with UPS systems for back-up power. These generally have lower levels of reliability than dc systems and the network needs to be designed such that overall reliability is not reduced through appropriate levels of redundancy. Mobile networks have different power requirements. Where there is a high density of nodes, continuity of service can be reasonably assured with short autonomy times. Furthermore, there is generally no requirement that these networks are the provider of last resort and therefore, specifications for continuity of power are directed towards revenue protection and overall reliability targets. As a result of these changes, battery requirements for reserve power are evolving. Shorter autonomy times are specified for parts of the network although a large part will continue to need support for hours rather minutes. Operational temperatures are increasing and battery solutions that provide longer life in extreme conditions are becoming important. Different battery technologies will be discussed in the context of these requirements. Conventional large flooded lead/acid cells both with pasted and tubular plates are used in larger central office applications but the majority of requirements are met with valve-regulated lead/acid (VRLA) batteries. The different types of VRLA battery will be described and their suitability for various applications outlined. New developments in battery construction and battery materials have improved both performance and reliability in recent years. Alternative technologies are also being proposed

Radiological findings for hip dysplasia at skeletal maturity. Validation of digital and manual measurement techniques.

Science.gov (United States)

Engesæter, Ingvild Øvstebø; Laborie, Lene Bjerke; Lehmann, Trude Gundersen; Sera, Francesco; Fevang, Jonas; Pedersen, Douglas; Morcuende, José; Lie, Stein Atle; Engesæter, Lars Birger; Rosendahl, Karen

2012-07-01

To report on intra-observer, inter-observer, and inter-method reliability and agreement for radiological measurements used in the diagnosis of hip dysplasia at skeletal maturity, as obtained by a manual and a digital measurement technique. Pelvic radiographs from 95 participants (56 females) in a follow-up hip study of 18- to 19-year-old patients were included. Eleven radiological measurements relevant for hip dysplasia (Sharp's, Wiberg's, and Ogata's angles; acetabular roof angle of Tönnis; articulo-trochanteric distance; acetabular depth-width ratio; femoral head extrusion index; maximum teardrop width; and the joint space width in three different locations) were validated. Three observers measured the radiographs using both a digital measurement program and manually in AgfaWeb1000. Inter-method and inter- and intra-observer agreement were analyzed using the mean differences between the readings/readers, establishing the 95% limits of agreement. We also calculated the minimum detectable change and the intra-class correlation coefficient. Large variations among different radiological measurements were demonstrated. However, the variation was not related to the use of either the manual or digital measurement technique. For measurements with greater absolute values (Sharp's angle, femoral head extrusion index, and acetabular depth-width ratio) the inter- and intra-observer and inter-method agreements were better as compared to measurements with lower absolute values (acetabular roof angle, teardrop and joint space width). The inter- and intra-observer variation differs notably across different radiological measurements relevant for hip dysplasia at skeletal maturity, a fact that should be taken into account in clinical practice. The agreement between the manual and digital methods is good.