To investigate the proportion of dysplastic hips which are retroverted. We studied the radiographs of over seven hundred patients with dysplastic hips who had had a periacetabular osteotomy in the period 1984–1998. We excluded patients with neuromuscular dysplasia, Perthes’ disease of the hip, post-traumatic dysplasia and proximal focal femoral deficiency. We selected 232 radiographs of patients with congenital acetabular dysplasia. A number of parameters were measured including lateral centre-edge angle, anterior centre-edge angle, acetabular index of weight-bearing surface, femoral head extrusion index and acetabular index of depth to width. Also recorded were acetabular version and congruency between femoral head and acetabulum. The lateral centre-edge angle of Wiberg had a mean value of 6.4° (SD 8.9°), the mean anterior centre-edge angle was 1.3° (SD 13.5°) and the acetabular index of weight-bearing surface of the acetabulum had a mean value of 24.5° (SD 9.7°). The majority (192, 82.8%) of acetabula were anteverted as might be expected. However, a significant minority (40, 17.2%) were retroverted. The mean anterior centre-edge angle in retroverted hips was 6.7° (SD 9.4°) compared with 0.4° (SD 13.3°) in anteverted hips. The authors have shown that, in a typical group of patients with congenital acetabular dysplasia significant enough to warrant periacetabular osteotomy, the majority of hips as expected have anteverted acetabula. However, a significant minority are retroverted. This finding has an important bearing on the performance of the osteotomy. We have also found that most if not all the information required prior to and following periac-etabular osteotomy can be obtained from an orthograde view of the pelvis

It is generally agreed that in acetabular dysplasia the acetabulum lies excessively anteverted. Although this is true for the majority of hips, we have found that in some patients with dysplastic hips, the acetabulum lies unexpectedly in retroversion. Aim: To investigate the proportion of dysplastic hips which are retroverted. Method: We studied the radiographs of over seven hundred patients with dysplastic hips and who had had a periacetabular osteotomy in the period 1984–1998. We excluded patients with neuromuscular dysplasia, Perthes disease of the hip, post-traumatic dysplasia and proximal focal femoral deficiency. We selected 232 radiographs of patients with congenital acetabular dysplasia. A number of parameters were measured including, lateral centre edge angle, anterior centre-edge angle, acetabular index of weight bearing surface, femoral head extrusion index and acetabular index of depth to width. Also recorded was acetabular version and congruency between femoral head and acetabulum. Results: The lateral centre-edge angle of Wiberg had a mean value of 6.4° (SD 8.9°), the mean anterior centre-edge angle was 1.3° (SD 13.5°) and the acetabular index of weight bearing surface of the acetabulum had a mean value of 24.5° (SD 9.7°). The majority (192, 82.8%) of acetabula were anteverted as might be expected. However, a significant minority (40,17.2%) were retroverted. The mean anterior centre-edge angle in retroverted hips was 6.7° (SD 9.4°) compared with 0.4° (SD 13.3°) in anteverted hips. Conclusion: The authors have shown that in a typical group of patients with congenital acetabular dysplasia, significant enough to warrant periacetabular osteotomy, the majority of hips as expected have anteverted acetabula. However, a significant minority are retroverted. This finding has an important bearing in the performance of the osteotomy

The purpose of this study was to evaluate the long-term clinical and radiological results of patients with hip dysplasia who underwent spherical acetabular osteotomy. The surgical technique used was that described by Wagner. The first 26 unilateral spherical osteotomies performed by one surgeon at one institution were reviewed at a minimum clinical follow-up of 20 years (median 23.9, maximum 29 years). One patient had died 5 years after the index operation unrelated to the procedure. Three patients (3 hips, 11 %) could not be traced. Preoperative and follow-up radiographic measurements included lateral and anterior centre-edge angle, acetabular index angle, and acetabulum-head index of Heyman and Herndon. Antero-posterior radiographs of the pelvis were evaluated for the presence of joint congruency, joint space narrowing, increased sclerosis of the subchondral bone, and bone cysts. Osteotomy improved the mean lateral centre-edge angle from −20 to +130, and the acetabular head index from 52% to 72%. The mean postoperative anterior centre-edge angle of Lequesne and de Seze was 23 (range: −10 to 62). Seven of 22 hips (32%) needed conversion to total hip replacement. The average Harris hip score at latest follow-up of the remaining 15 hips was rated 86 points (range: 50 to 100 points). Overall, 11 of the 15 hips were clinically rated good or excellent. On latest follow-up severity of osteoarthritis was unchanged in 13 of 15 hips. Only 3 of 9 hips requiring conversion to total hip replacement or showing progressive osteoarthritis were rated congruent after the index operation. On the other hand, 10 of 13 hips not requiring conversion to total hip replacement or progressive osteoarthritis were congruent. The 20-year-follow-up Kaplan-Meier survival estimates based on conversion to total hip replacement as an end point was 86.4%. (95% confidence interval: 63.4% to 95.4%). The 25-year-follow-up survivorship was 65.1 % (95% confidence interval: 35.6% to 83.7%). The long-term results of the spherical osteotomy are satisfactory from the standpoint of both improvement in clinical condition and the radiological appearance of the joint. The Wagner spherical osteotomy had prevented progression of degenerative changes in 13 out of 22 hips (59%) after a median 23.9 year follow-up. Congruency of the joint seems to be a major factor predicting long-term outcome

Aims

We assessed the long-term outcomes of a large cohort of patients who have undergone a periacetabular osteotomy (PAO), and sought to validate a patient satisfaction questionnaire for use in a PAO cohort.

Background: Numerous radiographic indices have been described to help define the degree of acetabular deficiency in adult patients with developmental dysplasia. The lateral centre-edge angle (LCE) of Wiberg and the anterior centre-edge (ACE) angle of Lequesne are two of the commonly measured indices that are reported in the evaluation of procedures that are used to correct acetabular deformity. Unfortunately much of the reported literature that tries to define abnormal indices has been extrapolated from the evaluation of “normal” pelvi or those with osteoarthritis. The purpose of this study was to evaluate the application and limitations of the LCE and ACE angles in a group of patients with developmental dysplasia treated with periacetabular osteotomy. Methods: 50 cases were randomly selected from a larger cohort of over 500 patients with acetabular dysplasia treated at our institution with periacetabular osteotomy. The preoperative and post osteotomy false profile and anteroposterior plain radiographs were reviewed. Cases were first grouped into one of three categories based on a general estimation of the location of acetabular deficiency as determined from the AP radiograph. A number of radiographic indices were measured and compared including the VCE angle, LCE angle, and acetabular angles of Tönnis and Sharp. Variation in both the VCE and LCE angle was evaluated by measuring the index using two different reference points. This included (1) the traditional mark of the furthest point along the sclerotic density of the weight bearing zone and (2) an alternate point representing the furthest extent of lateral or anterior bony coverage. Additional sources of measurement error were determined. The relationships between the centre-edge angles and other radiographic indices were determined. An evaluation of the indices and correction on post osteotomy radiographs was also performed. Results: Fifty cases in 45 patients were reviewed. There were 31 female and 19 males. The mean age was 30 years (range, 17–45). A general review of all preoperative AP radiographs revealed that all hips displayed some degree of lateral deficiency. Nineteen of these cases displayed a “classic” lateral and anterior deficiency. However, 19 cases displayed a more uniform deficiency and 12 cases were in fact retroverted. Evaluation of the radiographic indices revealed:. A mean VCE angle of 2.3 degrees (SD±12.7) and LCE angle of 3.4 degrees (SD±9.3). These were corrected to 25.8 degrees (SD±11.6) and 28.6 degrees (SD±8.7) following osteotomy. The VCE and LCE angles did not appear to be correlated (r=0.35). This is contrary to previous studies evaluating non-dysplastic pelvi (Chosa et al., 1997). The LCE angle showed no significant correlation to other lateral coverage indices (Tönnis, Sharp). No correlation was seen either in the post osteotomy values, or in the absolute degree of correction. The alternate VCE (aVCE), using the most anterior aspect of the acetabular margin as the reference point was consistently larger (p< 0.001) with a mean difference of 27.1 degrees (SD±10.0). There was however a positive correlation between these two methods of measurements (r=0.77). A similar variation was seen when comparing the LCE angle and the alternate LCE (aLCE). The mean difference between measurements was 7.3 degrees (SD±8.7)(p< 0.001). The mean VCE in hips with primarily anterior and lateral deficiency (−6.7°±12.5) was significantly lower (p< 0.01) than those with uniform deficiency (5.1°±8.3) or those with retroverted acetabuli (8.9°±13.3). Dysplastic hips with a decreased LCE angle but relatively normal Tönnis angle should be treated carefully as osteotomy may result in excessive angular correction in the coronal plane, thus creating a negative Tönnis angle. This can ultimately lead to problems with lateral and/or anterolateral impingement. Potential sources of error in measurement that were identified include:. Deformity of the acetabulum and occasional abnormalities of the femoral head limit the ability to identify the center of the rotation necessary to measure the centre-edge angles. Subluxation of the femoral head also creates a degree of error. These difficulties were observed in over 20% of cases. Alteration in pelvic tilt and rotation theoretically decreases the accuracy of measurement. Practically over 30% of radiographs were seen as less than ideal. The absolute reference point for VCE and LCE angles as the end of the sclerotic line in the weight bearing area can be (1) difficult to define (2) does not always represent the most anterior or lateral extent of the acetabular margin. This discrepancy appears to increases in dysplastic hips. This has been suggested previously (Fabeck et al.,1999) and is now supported by our findings. Conclusion: Centre-edge indices can be useful parameters in defining acetabular morphology. However, these parameters should not be used in isolation and the absolute values do little to define the overall location and degree of deficiency in hips with acetabular dysplasia. A number of significant sources of measurement error limit their accuracy especially in patients with hip dysplasia. Currently, it is our feeling that no single radiographic parameter fully defines the specific morphology in each individual case nor reflects the success of correction when treating patients with periacetabular osteotomy