Aims. The lateral centre-edge angle (LCEA) is a plain radiological measure of superolateral cover of the femoral head. This study aims to establish the correlation between 2D radiological and 3D CT measurements of acetabular morphology, and to describe the relationship between LCEA and femoral head cover (FHC). Methods. This retrospective study included 353 periacetabular osteotomies (PAOs) performed between January 2014 and December 2017. Overall, 97 hips in 75 patients had 3D analysis by Clinical Graphics, giving measurements for LCEA, acetabular index (AI), and FHC. Roentgenographical LCEA, AI, posterior wall index (PWI), and anterior wall index (AWI) were measured from supine AP pelvis radiographs. The correlation between CT and roentgenographical measurements was calculated. Sequential multiple linear regression was performed to determine the relationship between roentgenographical measurements and CT FHC. Results. CT-measured LCEA and AI correlated strongly with roentgenographical LCEA (r = 0.92; p < 0.001) and AI (r = 0.83; p < 0.001). Radiological LCEA correlated very strongly with CT FHC (r = 0.92; p < 0.001). The sum of AWI and PWI also correlated strongly with CTFHC (r = 0.73; p < 0.001). CT measurements of LCEA and AI were 3.4° less and 2.3° greater than radiological LCEA and AI measures. There was a linear relation between radiological LCEA and CT FHC. The linear regression model statistically significantly predicted FHC from LCEA, F(1,96) = 545.1 (p < 0.001), adjusted R. 2. = 85.0%, with the prediction equation: CT FHC(%) = 42.1 + 0.77(XRLCEA). Conclusion. CT and roentgenographical measurement of acetabular parameters are comparable. Currently, a radiological LCEA greater than 25° is considered normal. This study demonstrates that those with hip pain and normal radiological acetabular parameters may still have deficiencies in FHC. More sophisticated imaging techniques such as 3D CT should be considered for those with hip pain to identify deficiencies in FHC. Cite this article: Bone Jt Open 2022;3(1):12–19

Aims. Hip dysplasia (HD) leads to premature osteoarthritis. Timely detection and correction of HD has been shown to improve pain, functional status, and hip longevity. Several time-consuming radiological measurements are currently used to confirm HD. An artificial intelligence (AI) software named HIPPO automatically locates anatomical landmarks on anteroposterior pelvis radiographs and performs the needed measurements. The primary aim of this study was to assess the reliability of this tool as compared to multi-reader evaluation in clinically proven cases of adult HD. The secondary aims were to assess the time savings achieved and evaluate inter-reader assessment. Methods. A consecutive preoperative sample of 130 HD patients (256 hips) was used. This cohort included 82.3% females (n = 107) and 17.7% males (n = 23) with median patient age of 28.6 years (interquartile range (IQR) 22.5 to 37.2). Three trained readers’ measurements were compared to AI outputs of lateral centre-edge angle (LCEA), caput-collum-diaphyseal (CCD) angle, pelvic obliquity, Tönnis angle, Sharp’s angle, and femoral head coverage. Intraclass correlation coefficients (ICC) and Bland-Altman analyses were obtained. Results. Among 256 hips with AI outputs, all six hip AI measurements were successfully obtained. The AI-reader correlations were generally good (ICC 0.60 to 0.74) to excellent (ICC > 0.75). There was lower agreement for CCD angle measurement. Most widely used measurements for HD diagnosis (LCEA and Tönnis angle) demonstrated good to excellent inter-method reliability (ICC 0.71 to 0.86 and 0.82 to 0.90, respectively). The median reading time for the three readers and AI was 212 (IQR 197 to 230), 131 (IQR 126 to 147), 734 (IQR 690 to 786), and 41 (IQR 38 to 44) seconds, respectively. Conclusion. This study showed that AI-based software demonstrated reliable radiological assessment of patients with HD with significant interpretation-related time savings. Cite this article: Bone Jt Open 2022;3(11):877–884

Aims. Although there are various pelvic osteotomies for acetabular dysplasia of the hip, shelf operations offer effective and minimally invasive osteotomy. Our study aimed to assess outcomes following modified Spitzy shelf acetabuloplasty. Methods. Between November 2000 and December 2016, we retrospectively evaluated 144 consecutive hip procedures in 122 patients a minimum of five years after undergoing modified Spitzy shelf acetabuloplasty for acetabular dysplasia including osteoarthritis (OA). Our follow-up rate was 92%. The mean age at time of surgery was 37 years (13 to 58), with a mean follow-up of 11 years (5 to 21). Advanced OA (Tönnis grade ≥ 2) was present preoperatively in 16 hips (11%). The preoperative lateral centre-edge angle ranged from -28° to 25°. Survival was determined by Kaplan-Meier analysis, using conversions to total hip arthroplasty as the endpoint. Risk factors for joint space narrowing less than 2 mm were analyzed using a Cox proportional hazards model. Results. The mean Merle d'Aubigné clinical score improved from 11.6 points (6 to 17) preoperatively to 15.9 points (12 to 18) at the last follow-up. The survival rates were 95% (95% confidence interval (CI) 91 to 99) and 86% (95% CI 50 to 97) at ten and 15 years. Multivariate Cox regression identified three factors associated with radiological OA progression: age (hazard ratio (HR) 2.85, 95% CI 1.05 to 7.76; p = 0.0398), preoperative joint space (HR 2.41, 95% CI 1.35 to 4.29; p = 0.0029), and preoperative OA (HR 8.34, 95% CI 0.94 to 73.77; p = 0.0466). Conclusion. Modified Spitzy shelf acetabuloplasty is an effective joint-preserving surgery with a wide range of potential indications. Cite this article: Bone Jt Open 2023;4(12):932–941

Aims. Radiological residual acetabular dysplasia (RAD) has been reported in up to 30% of children who had successful brace treatment of infant developmental dysplasia of the hip (DDH). Predicting those who will resolve and those who may need corrective surgery is important to optimize follow-up protocols. In this study we have aimed to identify the prevalence and predictors of RAD at two years and five years post-bracing. Methods. This was a single-centre, prospective longitudinal cohort study of infants with DDH managed using a published, standardized Pavlik harness protocol between January 2012 and December 2016. RAD was measured at two years’ mean follow-up using acetabular index-lateral edge (AI-L) and acetabular index-sourcil (AI-S), and at five years using AI-L, AI-S, centre-edge angle (CEA), and acetabular depth ratio (ADR). Each hip was classified based on published normative values for normal, borderline (1 to 2 standard deviations (SDs)), or dysplastic (> 2 SDs) based on sex, age, and laterality. Results. Of 202 infants who completed the protocol, 181 (90%) had two and five years’ follow-up radiographs. At two years, in 304 initially pathological hips, the prevalence of RAD (dysplastic) was 10% and RAD (borderline) was 30%. At five years, RAD (dysplastic) decreased to 1% to 3% and RAD (borderline) decreased to < 1% to 2%. On logistic regression, no variables were predictive of RAD at two years. Only AI-L at two years was predictive of RAD at five years (p < 0.001). If both hips were normal at two years’ follow-up (n = 96), all remained normal at five years. In those with bilateral borderline hips at two years (n = 21), only two were borderline at five years, none were dysplastic. In those with either borderline-dysplastic or bilateral dysplasia at two years (n = 26), three (12%) were dysplastic at five years. Conclusion. The majority of patients with RAD at two years post-brace treatment, spontaneously resolved by five years. Therefore, children with normal radiographs at two years post-brace treatment can be discharged. Targeted follow-up for those with abnormal AI-L at two years will identify the few who may benefit from surgical correction at five years’ follow-up. Cite this article: Bone Joint J 2024;106-B(7):744–750

Aims. Brace treatment is the cornerstone of managing developmental dysplasia of the hip (DDH), yet there is a lack of evidence-based treatment protocols, which results in wide variations in practice. To resolve this, we have developed a comprehensive nonoperative treatment protocol conforming to published consensus principles, with well-defined a priori criteria for inclusion and successful treatment. Methods. This was a single-centre, prospective, longitudinal cohort study of a consecutive series of infants with ultrasound-confirmed DDH who underwent a comprehensive nonoperative brace management protocol in a unified multidisciplinary clinic between January 2012 and December 2016 with five-year follow-up radiographs. The radiological outcomes were acetabular index-lateral edge (AI-L), acetabular index-sourcil (AI-S), centre-edge angle (CEA), acetabular depth ratio (ADR), International Hip Dysplasia Institute (IHDI) grade, and evidence of avascular necrosis (AVN). At five years, each hip was classified as normal (< 1 SD), borderline dysplastic (1 to 2 SDs), or dysplastic (> 2 SDs) based on validated radiological norm-referenced values. Results. Of 993 infants assessed clinically and sonographically, 21% (212 infants, 354 abnormal hips) had DDH and were included. Of these, 95% (202 infants, 335 hips) successfully completed bracing, and 5% (ten infants, 19 hips) failed bracing due to irreducible hip(s). The success rate of bracing for unilateral dislocations was 88% (45/51 infants) and for bilateral dislocations 83% (20/24 infants). The femoral nerve palsy rate was 1% (2/212 infants). At five-year follow-up (mean 63 months (SD 5.9; 49 to 83)) the prevalence of residual dysplasia after successful brace treatment was 1.6% (5/312 hips). All hips were IHDI grade I and none had AVN. Four children (4/186; 2%) subsequently underwent surgery for residual dysplasia. Conclusion. Our comprehensive protocol for nonoperative treatment of infant DDH has shown high rates of success and extremely low rates of residual dysplasia at a mean age of five years. Cite this article: Bone Joint J 2023;105-B(8):935–942

Aims. Metal-on-metal hip resurfacing (MoM-HR) has seen decreased usage due to safety and longevity concerns. Joint registries have highlighted the risks in females, smaller hips, and hip dysplasia. This study aimed to identify if reported risk factors are linked to revision in a long-term follow-up of MoM-HR performed by a non-designer surgeon. Methods. A retrospective review of consecutive MoM hip arthroplasties (MoM-HRAs) using Birmingham Hip Resurfacing was conducted. Data on procedure side, indication, implant sizes and orientation, highest blood cobalt and chromium ion concentrations, and all-cause revision were collected from local and UK National Joint Registry records. Results. A total of 243 hips (205 patients (163 male, 80 female; mean age at surgery 55.3 years (range 25.7 to 75.3)) with MoM-HRA performed between April 2003 and October 2020 were included. Mean follow-up was 11.2 years (range 0.3 to 17.8). Osteoarthritis was the most common indication (93.8%), and 13 hips (5.3%; 7M:6F) showed dysplasia (lateral centre-edge angle < 25°). Acetabular cups were implanted at a median of 45.4° abduction (interquartile range 41.9° - 48.3°) and stems neutral or valgus to the native neck-shaft angle. In all, 11 hips (4.5%; one male, ten females) in ten patients underwent revision surgery at a mean of 7.4 years (range 2.8 to 14.2), giving a cumulative survival rate of 94.8% (95% confidence interval (CI) 91.6% to 98.0%) at ten years, and 93.4% (95% CI 89.3% to 97.6%) at 17 years. For aseptic revision, male survivorship was 100% at 17 years, and 89.6% (95% CI 83.1% to 96.7%) at ten and 17 years for females. Increased metal ion levels were implicated in 50% of female revisions, with the remaining being revised for unexplained pain or avascular necrosis. Conclusion. The Birmingham MoM-HR showed 100% survivorship in males, exceeding the National Institute for Health and Care Excellence ‘5% at ten years’ threshold. Female sex and small component sizes are independent risk factors. Dysplasia alone is not a contraindication to resurfacing. Cite this article: Bone Jt Open 2023;4(11):853–858

Aims. Periacetabular osteotomy (PAO) is an established treatment for acetabular dysplasia. It has also been proposed as a treatment for patients with acetabular retroversion. By reviewing a large cohort, we aimed to test whether outcome is equivalent for both types of morphology and identify factors that influenced outcome. Methods. A single-centre, retrospective cohort study was performed on patients with acetabular retroversion treated with PAO (n = 62 hips). Acetabular retroversion was diagnosed clinically and radiologically (presence of a crossover sign, posterior wall sign, lateral centre-edge angle (LCEA) between 20° and 35°). Outcomes were compared with a control group of patients undergoing PAO for dysplasia (LCEA < 20°; n = 86 hips). Femoral version was recorded. Patient-reported outcome measures (PROMs), complications, and reoperation rates were measured. Results. The mean Non-Arthritic Hip Score (NAHS) preoperatively was 58.6 (SD 16.1) for the dysplastic hips and 52.5 (SD 12.7) for the retroverted hips (p = 0.145). Postoperatively, mean NAHS was 83.0 (SD 16.9) and 76.7 (SD 17.9) for dysplastic and retroverted hips respectively (p = 0.041). Difference between pre- and postoperative NAHS was slightly lower in the retroverted hips (18.3 (SD 22.1)) compared to the dysplastic hips (25.2 (SD 15.2); p = 0.230). At mean 3.5 years’ follow-up (SD 1.9), one hip needed a revision PAO and no hips were converted to total hip arthroplasty (THA) in the retroversion group. In the control group, six hips (7.0%) were revised to THA. No differences in complications (p = 0.106) or in reoperation rate (p = 0.087) were seen. Negative predictors of outcome for patients undergoing surgery for retroversion were female sex, obesity, hypermobility, and severely decreased femoral anteversion. Conclusion. A PAO is an effective surgical intervention for acetabular retroversion and produces similar improvements when used to treat dysplasia. Femoral version should be routinely assessed in these patients and when extremely low (< 0°), as an additional procedure to address this abnormality may be necessary. Females with signs of hypermobility should also be consulted of the likely guarded improvement. Cite this article: Bone Jt Open 2021;2(9):757–764

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

Acetabular retroversion is a recognised cause of hip impingement. Pelvic tilt influences acetabular orientation and is known to change in different functional positions. While previously reported in patients with developmental dysplasia of the hip, positional changes in pelvic tilt have not been studied in patients with acetabular retroversion. We retrospectively analysed supine and standing AP pelvic radiographs in 22 patients with preoperative radiographs and 47 with post-operative radiographs treated for symptomatic acetabular retroversion. Measurements were made for acetabular index (AI), lateral centre-edge angle (LCEA), crossover index, ischial spine sign, and posterior wall sign. The change in pelvic tilt angle was measured both by the Sacro-Femoral-Pubic (SFP) angle and the Pubic Symphysis to Sacro-iliac (PS-SI) Index. In the supine position, the mean calculated pelvic tilt angle (by SFP) was 1.05° which changed on standing to a pelvic tilt of 8.64°. A significant increase in posterior pelvic tilt angle from supine to standing of 7.59° (SFP angle) and 5.89° (PS –SI index) was calculated (p<0.001;paired t-test). There was a good correlation in pelvic tilt change between measurements using SFP angle and PS-SI index (rho .901 in pre-op group, rho .815 in post-op group). Signs of retroversion were significantly reduced in standing x-rays compared to supine: Crossover index (0.16 vs 0.38; p<0.001) crossover sign (19/28 vs 28/28 hips; p<0.001), ischial spine sign (10/28 hips vs 26/28 hips; p<0.001) and posterior wall sign (12/28 vs 24/28 hips; p<0.001). Posterior pelvic tilt increased from supine to standing in patients with symptomatic acetabular retroversion, in keeping with previous studies of pelvic tilt change in patients with hip dysplasia. The features of acetabular retroversion were much less evident on standing radiographs. The low pelvic tilt angle in the supine position is implicated in the appearance of acetabular retroversion in the supine position. Patients presenting with symptoms of hip impingement should be assessed by supine and standing pelvic radiographs so as not to miss signs of retroversion and to assist with optimising acetabular correction at the time of surgery

Acetabular retroversion is a recognised cause of hip impingement. Pelvic tilt influences acetabular orientation and is known to change in different functional positions. While previously reported in patients with developmental dysplasia of the hip, positional changes in pelvic tilt have not been studied in patients with acetabular retroversion. We retrospectively analysed supine and standing AP pelvic radiographs in 22 patients with preoperative radiographs and 47 with post-operative radiographs treated for symptomatic acetabular retroversion. Measurements were made for acetabular index (AI), lateral centre-edge angle (LCEA), crossover index, ischial spine sign, and posterior wall sign. The change in pelvic tilt angle was measured both by the Sacro-Femoral-Pubic (SFP) angle and the Pubic Symphysis to Sacro-iliac (PS-SI) Index. In the supine position, the mean calculated pelvic tilt angle (by SFP) was 1.05° which changed on standing to a pelvic tilt of 8.64°. A significant increase in posterior pelvic tilt angle from supine to standing of 7.59° (SFP angle) and 5.89° (PS –SI index) was calculated (p<0.001;paired t-test). The mean pelvic tilt change of 6.51° measured on post-operative Xrays was not significantly different (p=.650). There was a good correlation in pelvic tilt change between measurements using SFP angle and PS-SI index (rho .901 in pre-op group, rho .815 in post-op group). Signs of retroversion were significantly reduced in standing x-rays compared to supine: Crossover index (0.16 vs 0.38; p<0.001) crossover sign (19/28 vs 28/28 hips; p<0.001), ischial spine sign (10/28 hips vs 26/28 hips; p<0.001) and posterior wall sign (12/28 vs 24/28 hips; p<0.001). Posterior pelvic tilt increased from supine to standing in patients with symptomatic acetabular retroversion, in keeping with previous studies of pelvic tilt change in patients with hip dysplasia. The features of acetabular retroversion were much less evident on standing radiographs. The low pelvic tilt angle in the supine position is implicated in the appearance of acetabular retroversion in the supine position. Patients presenting with symptoms of hip impingement should be assessed by supine and standing pelvic radiographs so as not to miss signs of retroversion and to assist with optimising acetabular correction at the time of surgery

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

Periacetabular osteotomy (PAO) has been established as an effective technique to treat symptomatic hip dysplasia in young patients. Its role in treating borderline dysplasia and acetabular retroversion is evolving. The aim of this study was to:. Examine the prospectively collected outcomes following a minimally invasive PAO in a large cohort of patients. Compare the outcomes of patients with severe dysplasia, borderline dysplasia and acetabular retroversion. This is a single-surgeon review of patients operated in a high-volume centre with prospectively collected data between 2013 and 2020, and minimal followup of six months. PAO was performed using a minimally invasive modified Smith Peterson approach. 387 patients were operated during the study period and 369 eligible patients included in the final analysis. Radiographic parameters were assessed by two authors (GS and KB) with interrater reliability for 25 patients of 84–95% (IntraClass Coefficient). Patient reported outcome measures (i-HOT 12, NAHS, UCLA and EQ-5D) were collected prospectively. Case note review was also performed to collate complication data and blood transfusion rates. Radiological parameters improved significantly after surgery with Lateral centre-edge angle (LCEA) improving by 16.4 degrees and Acetabular index (AI) improved by 15.8 degrees. Patient reported outcome measures showed significant improvement in post-op NAHS, iHOT and EQ5D at 2 years compared to pre-op scores (NAHS=30.45, iHOT=42, EQ5D=0.32, p=0.01). This significance is maintained over 2 years post procedure (p=0.001). There was no significant difference between the three groups (severe dysplasia, borderline dysplasia and acetabular retroversion). Clinical outcomes showed an overall complication rate n=31, 8.3% (Major complication rate: n=3, 0.81%). Non-union rate: n=11, 2.96% of which 3 required fixation (0.81%). Hip arthroscopy post PAO: n=7, 1.9%. Conversion to THR: n=4, 1.1%. Blood transfusion requirement: n=46, 12.5%. No patient developed a major neurovascular injury. In this large single-centre study, patients had radiological and reported outcome improvements following surgery. Overall, there was a low complication rate, providing further evidence of the safety and efficacy of PAO for ameliorating pain and long-lasting results in the management of symptomatic hip dysplasia

Introduction. Joint preserving procedures have gained popularity in an attempt to delay arthroplasty in young, dysplastic hips. Excellent results can be achieved with peri-acetabular osteotomy (PAO) in congruent non-arthritic hips. The role of salvage procedures such as the Shelf acetabuloplasty remains undefined. This study aims to determine the long-term survival and functional outcome following Shelf acetabuloplasty and to identify factors that influence outcome. Patients/Materials & Methods. This is a retrospective, consecutive, multi-surgeon, case series from a UK referral centre. 125 Shelf procedures were performed between 1987–2013 on 117 patients for symptomatic hip dysplasia. Mean age was 33 years (15–53). Mean follow-up was 10 years (1–27). Radiographic parameters measured included pre-operative arthritis, acetabular-index, centre-edge-angle, joint congruency, subluxation and femoral sphericity. Oxford Hip and UCLA scores were collected at follow-up. Failure was defined as conversion to arthroplasty or OHS<20. Results. The acetabular index and centre-edge angles have been improved from 23° (SD:9) and 12° (SD:8) pre-operatively to 10° (SD:9) and 45° (SD:11) post-operatively. By follow-up, 63 hips (50%) had converted to arthroplasty. The mean OHS and UCLA scores were 33 (SD:12) and 6 (SD:3), respectively. Survival rates were 82% at 5 years, 60% at 10 years and 43% at 15 years. The only factor influencing 10-yr survival was minimal pre-op arthritis (65% Vs 40%, p=0.02). Optimal functional outcome was seen when post-operative centre-edge angle was between 20–40° (p=0.01). Discussion. This largest long-term series of Shelf acetabuloplasties reported to-date emphasises the value of this procedure in patients that pose treatment dilemmas as they are symptomatic, too young for arthroplasty but have features that make them unsuitable for PAO. Never-the-less, in 60% of cases a Shelf acetabuloplasty will delay arthroplasty for 10 years. If performed in patients with minimal arthritis and congruent joint 10-year survival is 85%. Conclusion. Shelf acetabuloplasty is a simple, reliable procedure with good mid- to long-term results

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

Purpose of study. This study is to determine the survival and outcomes of the Birmingham Interlocking Triple Pelvic Osteotomy. A dysplastic hip predisposes to early arthritis. The Triple Pelvic Osteotomy (TPO) is a joint-preserving option for the treatment of young adults with hip dysplasia. The long term success of the procedure is not known. Patients and methods. The senior author has been performing Birmingham Interlocking Triple Pelvic Osteotomies for 18 years. The outcomes of the first 100 patients (117 TPOs) were reviewed using postal questionnaires, telephone interviews and radiograph review. The primary outcome measure of the study was the Kaplan—Meier survival curve for the TPO. Hip replacement or resurfacing were taken as failure points. The Oxford Hip Score (OHS) and University of California, Los Angeles (UCLA) score were used as secondary outcome measures for the surviving osteotomies. The pre-and post-operative acetabular index and centre-edge angles were measured from surviving radiographs. Results. Follow-up was 93% for survivorship. The mean age at operation was 31 years (range of 7 to 57 years). The mean pre- and post-operative centre-edge angles were 19°and 50° and acetabular indices were 23° and 2°. The Kaplan-Meier survival curve demonstrates that the 10, 15 and 18-year survival rates are 76%, 57% and 50% respectively. Survival was 89% if the osteotomy was performed before 20 years of age. The median UCLA score was five (inter-quartile range three to seven). Median OHS was 41 (inter-quartile range 24 to 46). The UCLA and OHSs show that those with surviving osteotomies tend to have good hip function. Conclusions. The Birmingham Interlocking Pelvic Osteotomy provides a valuable tool to preserve dysplastic hip function and delay arthroplasty surgery, particularly in the younger patient. It is best performed early before arthritis sets in

Aim: To assess the outcome for Perthes disease in children over eight treated by observation, varus osteotomy, abduction plasters and acetabular augmentation. Methods and results: A retrospective case note review of prospectively collected data for 44 children (48) hips with Catterall grades 2, 3 or 4 Perthes’ disease with onset age eight or older and followed to maturity was performed. The groups were demographically similar. For all groups combined 60% had a satisfactory Stulberg grade I to III outcome. Poorer outcomes (as assessed by Stulberg, centre edge angle and Reimer’s migration index) were associated with increasing age, greater initial head deformity and greater head involvement. Initial head deformity did not remodel for any treatment group. Indeed, progressive head deformity occurred despite plaster treatment or varus osteotomy but not after acetabular augmentation. Hips managed by acetabular augmentation also had better outcomes than the other groups for Stulberg, Reimer’s index and centre-edge angle. Conclusions: Whatever the treatment the outcome for Perthes’ disease in children over eight is poorer with increasing age. No treatment offers the prospect of a good result in the older child with significant head involvement or significant initial deformity but acetabular augmentation seems to improve Stulberg, Reimer’s migration and centre-edge angle outcomes and prevents progressive femoral head deformity compared with observation, varus osteotomy and plaster treatment

The results of a functional, clinical and radiological study of 30 children (60 hips) with whole body cerebral palsy are presented with a mean follow-up of ten years. Bilateral simultaneous combined soft-tissue and bony surgery was performed at a mean age of 7.7 years (3.1–12.2). Evaluation involved interviews with patient/carers and clinical examination. Plain radiographs of the pelvis assessed migration percentage and centre-edge angle. Twenty two patients were recalled. Five had died of unrelated causes and three were lost to follow-up. Pain was uncommon, present in 1 patient (4.5%). Improved handling was reported in 18 of 22 patients (82%). Carer handling problems were attributed to growth of the patients. All patients/carers considered the procedure worthwhile. The range of hip movements improved, with a mean windsweep index of 36 (50 pre-operatively). Radiological containment improved, with mean migration percentage of 20 degrees (50 preoperatively) and mean centre-edge angle of 29 degrees (−5 preoperatively) No statistical difference was noted between the three year and ten year follow-up results demonstrating maintained clinical and radiological outcome improvement. In conclusion, we consider that bilateral simultaneous combined hip reconstruction in whole body cerebral palsy provides painless, mobile and anatomically competent hips in the long term

Introduction and Objectives: The aim of this study is to analyze changes seen on X-ray of the acetabular index, Wiberg’s angle, Sharp’s angle and the continuity of Shenton’s line after osteotomy performed by means of the Dega technique in developmental dysplasia of the hip (DDH). Materials and Methods: We retrospectively analyzed 72 histories of children that underwent surgery performed using the Dega technique at the Niño Jesús Hospital over the last 15 years. We measured the rupture of the Shenton line, the acetabular index, Wiberg’s centre-edge angle and Sharp’s acetabular angle preoperatively; and then approximately 1 year after surgery and at the last X-ray control in the medical history. Results: The acetabular index changed from 33° preoperatively to 24° one year after surgery. At the last X-ray control the acetabular index was 23°. Wiberg’s centre-edge angle is normalized by osteotomy, and changed from 6° preoperatively to 20° after surgery. At the last X-ray it was 23°. However, Sharp’s acetabular angle only suffered slight modifications. It changed from 50° to 48° with surgery. Discussion and Conclusions: The Dega osteotomy is an effective technique to provide acetabular coverage in hips suffering from dysplasia before the closure of the triradiate cartilage. Both the acetabular index and Wiberg’s angle vary significantly with surgery, and become normalized in most cases. This correction is stable over time. However, the same cannot be said for Sharp’s acetabular angle which barely changes with osteotomy

Purpose of study: To assess functional, clinical and radiological outcomes of 30 children (60 hips) with whole body cerebral palsy with a mean follow-up of ten years. Method: Bilateral simultaneous combined soft-tissue and bony hip surgery was performed at a mean age of 7.7 years (3.1–12.2). Evaluation at ten years involved interviews with patient/carers and clinical examination. Plane radiographs of the pelvis assessed migration percentage and centre-edge angle. Results: Twenty two patients were recalled. Five had died of unrelated causes and three were lost to follow-up. Pain was present in only 1 patient (4.5%). Improved handling was reported in 18 of 22 patients (82%). Carer handling problems were attributed to growth of the patients. All patients/carers considered the procedure worthwhile. The range of hip movements improved, with a mean windsweep index of 36 (50 pre-operatively) Radiological containment improved, with mean migration percentage of 20 degrees (50 preoperatively) and mean centre-edge angle of 29 degrees (−5 preoperatively) No statistical difference was noted between the three year and ten year follow-up results, demonstrating sustained improvement in the clinical and radiological outcome. Conclusions: Bilateral simultaneous combined hip reconstruction in whole body cerebral palsy provides painless, mobile and anatomically competent hips in the longer term. The majority of the available literature considers the short term outcome of surgical reconstruction of the hips in this condition. This paper demonstrates that the initial improvements in structure and function are maintained in the longer term