Long-term results of spherical acetabular osteotomy.
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We have examined the effect of the Wagner spherical acetabular osteotomy on preserving the joint in 38 hips with a mean follow-up of 17 years. At the time of the initial operation, 55% of patients had clinical symptoms and 30 joints showed minimal or absent radiological signs of osteoarthritis. At follow-up, 54% of patients had a good functional result. The osteotomy improved the mean centre-edge angle from -3 degrees to +15 degrees, the mean anterior centre-edge angle to 23 degrees and the acetabular head index to 75%. The obliquity of the acetabular roof decreased from 28 degrees to 16 degrees. One patient improved, but 14 deteriorated with joint degeneration. Of these, one progressed because of postoperative deep-tissue infection and five due to undercorrection. One patient needed total joint replacement after 14 years. At 17 years after operation, Wagner osteotomy had prevented progression of secondary arthritis in 63% of cases. (+info)
Non-operative management of acetabular fractures. The use of dynamic stress views.
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To assess the stability of the hip after acetabular fracture, dynamic fluoroscopic stress views were taken of 41 acetabular fractures that met the criteria for non-operative management. These included roof arcs of 45 degrees, a subchondral CT arc of 10 mm, displacement of less than 50% of the posterior wall, and congruence on the AP and Judet views of the hip. There were three unstable hips which were treated by open reduction and internal fixation. The remaining 38 fractures were treated non-operatively with early mobilisation and delayed weight-bearing. At a mean follow-up of 2.7 years, the results were good or excellent in 91% of the cases. Three fair results were ascribed to the patients' other injuries. Dynamic stress views can identify subtle instability in patients who would normally be considered for non-operative treatment. (+info)
Open reduction and internal fixation of acetabular fractures.
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Between 1982 and 1995, 84 patients with displaced acetabular fractures underwent open reduction and internal fixation in our institution. The mean follow-up was 5.5 years with a minimum of 2 years. There were 33 simple and 51 complex fractures according to the classification of Judet and Letournels. Reduction after operation was anatomical in 49% of the patients, satisfactory in 24%, and unsatisfactory in 27%. Using Merle d'Aubigne's scale, the clinical results were excellent in 39% of the patients, good in 29%, fair in 8%, and poor in 24%. Factors of statistical significance associated with a poor clinical outcome were T-shaped fractures, unsatisfactory reduction (> 3 mm residual displacement), age > 40 years and development of avascular necrosis. Acetabular surgery is demanding, and a high rate of complications can be expected. Trauma centres should designate a group of surgeons who will consistently treat these fractures in order to obtain more experience and better results. (+info)
The influence of weight-bearing on the measurement of polyethylene wear in THA.
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We have studied the influence of weight-bearing on the measurement of wear of the polyethylene acetabular component in total hip arthroplasty using two techniques. The measured vertical wear was significantly greater when radiographs were taken weight-bearing rather than with the patient supine (p = 0.001, method 1; p = 0.007, method 2). Calculations of rates of linear wear of the acetabular component were significantly underestimated (p < 0.05) when radiographs were taken supine. There are two reasons for this. First, a change in pelvic orientation when bearing weight ensures that the thinnest polyethylene is brought into relief, and secondly, the head of the femoral component assumes the position of maximal displacement along its wear path. Interpretation of previous studies on both linear and volumetric polyethylene wear in total hip arthroplasty should be reassessed in the light of these findings. (+info)
Accuracy of EBRA-FCA in the measurement of migration of femoral components of total hip replacement. Einzel-Bild-Rontgen-Analyse-femoral component analysis.
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Several methods of measuring the migration of the femoral component after total hip replacement have been described, but they use different reference lines, and have differing accuracies, some unproven. Statistical comparison of different studies is rarely possible. We report a study of the EBRA-FCA method (femoral component analysis using Einzel-Bild-Rontgen-Analyse) to determine its accuracy using three independent assessments, including a direct comparison with the results of roentgen stereophotogrammetric analysis (RSA). The accuracy of EBRA-FCA was better than +/- 1.5 mm (95% percentile) with a Cronbach's coefficient alpha for interobserver reliability of 0.84; a very good result. The method had a specificity of 100% and a sensitivity of 78% compared with RSA for the detection of migration of over 1 mm. This is accurate enough to assess the stability of a prosthesis within a relatively limited period. The best reference line for downward migration is between the greater trochanter and the shoulder of the stem, as confirmed by two experimental analyses and a computer-assisted design. (+info)
The prediction of failure of the stem in THR by measurement of early migration using EBRA-FCA. Einzel-Bild-Roentgen-Analyse-femoral component analysis.
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We report the ten-year results for three designs of stem in 240 total hip replacements, for which subsidence had been measured on plain radiographs at regular intervals. Accurate migration patterns could be determined by the method of Einzel-Bild-Roentgen-Analyse-femoral component analysis (EBRA-FCA) for 158 hips (66%). Of these, 108 stems (68%) remained stable throughout, and five (3%) started to migrate after a median of 54 months. Initial migration of at least 1 mm was seen in 45 stems (29%) during the first two years, but these then became stable. We revised 17 stems for aseptic loosening, and 12 for other reasons. Revision for aseptic loosening could be predicted by EBRA-FCA with a sensitivity of 69%, a specificity of 80%, and an accuracy of 79% by the use of a threshold of subsidence of 1.5 mm during the first two years. Similar observations over a five-year period allowed the long-term outcome to be predicted with an accuracy of 91%. We discuss the importance of four different patterns of subsidence and confirm that the early measurement of migration by a reasonably accurate method can help to predict long-term outcome. Such methods should be used to evaluate new and modified designs of prosthesis. (+info)
Retroversion of the acetabulum. A cause of hip pain.
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We describe a little-known variety of hip dysplasia, termed 'acetabular retroversion', in which the alignment of the mouth of the acetabulum does not face the normal anterolateral direction, but inclines more posterolaterally. The condition may be part of a complex dysplasia or a single entity. Other than its retroversion, the acetabulum is sited normally on the side wall of the pelvis, and its articular surface is of normal extent and configuration. The retroverted orientation may give rise to problems of impingement between the femoral neck and anterior acetabular edge. We define the clinical and radiological parameters and discuss pathological changes which may occur in the untreated condition. A technique of management is proposed. (+info)
Improving the detection of acetabular osteolysis using oblique radiographs.
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Visualisation of periacetabular osteolysis by standard anteroposterior (AP) radiographs underestimates the extent of bone loss around a metal-backed acetabular component. We have assessed the effectiveness of standard radiological views in depicting periacetabular osteolysis, and recommend additional projections which make these lesions more visible. This was accomplished using a computerised simulation of radiological views and a radiological analysis of simulated defects placed at regular intervals around the perimeter of a cadaver acetabulum. The AP view alone showed only 38% of the defects over all of the surface of the cup and failed to depict a 3 mm lesion over 83% of the cup. When combined with the AP view, additional 45 degree obturator-oblique and iliac-oblique projections increased the depiction, showing 81% of the defects. The addition of the 60 degree obturator-oblique view further improved the visualisation of posterior defects, increasing the rate of detection to 94%. Based on this analysis, we recommend using at least three radiographic views when assessing the presence and extent of acetabular osteolysis. (+info)