Patients with acetabular dysplasia commonly undergo peri-acetabular osteotomy after skeletal maturity to reduce the risk of the late development of osteoarthritis. Several studies have suggested that deformity of the femoral head influences the long-term outcome. We radiologically examined 224 hips in 112 patients with acetabular dysplasia and early-stage osteoarthritis. There were 103 women and nine men with a mean age of 37.6 years (18 to 49). A total of 201 hips were placed in the acetabular dysplasia group and 23 in a normal group. The centre–edge angle and acetabular head index were significantly smaller (both p < 0.001), and the acetabular angle, acetabular roof angle and roundness index were significantly greater in the acetabular dysplasia group than those in the normal group (all p < 0.001). There were significant correlations between the roundness index and other parameters. Femoral head shape may be influenced by the severity of the acetabular dysplasia. Cite this article: Bone Joint J 2013;95-B:1192–6

Aims. The aim of the current study was to assess the reliability of the Ottawa classification for symptomatic acetabular dysplasia. Methods. In all, 134 consecutive hips that underwent periacetabular osteotomy were categorized using a validated software (Hip2Norm) into four categories of normal, lateral/global, anterior, or posterior. A total of 74 cases were selected for reliability analysis, and these included 44 dysplastic and 30 normal hips. A group of six blinded fellowship-trained raters, provided with the classification system, looked at these radiographs at two separate timepoints to classify the hips using standard radiological measurements. Thereafter, a consensus meeting was held where a modified flow diagram was devised, before a third reading by four raters using a separate set of 74 radiographs took place. Results. Intrarater results per surgeon between Time 1 and Time 2 showed substantial to almost perfect agreement among the raters (κappa = 0.416 to 0.873). With respect to inter-rater reliability, at Time 1 and Time 2 there was substantial agreement overall between all surgeons (Time 1 κappa = 0.619; Time 2 κappa = 0.623). Posterior and anterior rating categories had moderate and fair agreement at Time 1 (posterior κappa = 0.557; anterior κappa = 0.438) and Time 2 (posterior κappa = 0.506; anterior κappa = 0.250), respectively. At Time 3, overall reliability (κappa = 0.687) and posterior and anterior reliability (posterior κappa = 0.579; anterior κappa = 0.521) improved from Time 1 and Time 2. Conclusion. The Ottawa classification system provides a reliable way to identify three categories of acetabular dysplasia that are well-aligned with surgical management. The term ‘borderline dysplasia’ should no longer be used. Cite this article: Bone Joint Res. 2020;9(5):242–249

Objectives. We have previously investigated an association between the genome copy number variation (CNV) and acetabular dysplasia (AD). Hip osteoarthritis is associated with a genetic polymorphism in the aspartic acid repeat in the N-terminal region of the asporin (ASPN) gene; therefore, the present study aimed to investigate whether the CNV of ASPN is involved in the pathogenesis of AD. Methods. Acetabular coverage of all subjects was evaluated using radiological findings (Sharp angle, centre-edge (CE) angle, acetabular roof obliquity (ARO) angle, and minimum joint space width). Genomic DNA was extracted from peripheral blood leukocytes. Agilent’s region-targeted high-density oligonucleotide tiling microarray was used to analyse 64 female AD patients and 32 female control subjects. All statistical analyses were performed using EZR software (Fisher’s exact probability test, Pearson’s correlation test, and Student’s t-test). Results. CNV analysis of the ASPN gene revealed a copy number loss in significantly more AD patients (9/64) than control subjects (0/32; p = 0.0212). This loss occurred within a 60 kb region on 9q22.31, which harbours the gene for ASPN. The mean radiological parameters of these AD patients were significantly worse than those of the other subjects (Sharp angle, p = 0.0056; CE angle, p = 0.0076; ARO angle, p = 0.0065), and all nine patients required operative therapy such as total hip arthroplasty or pelvic osteotomy. Moreover, six of these nine patients had a history of operative or conservative therapy for developmental dysplasia of the hip. Conclusions. Copy number loss within the region harbouring the ASPN gene on 9q22.31 is associated with severe AD. A copy number loss in the ASPN gene region may play a role in the aetiology of severe AD. Cite this article: T. Sekimoto, M. Ishii, M. Emi, S. Kurogi, T. Funamoto, Y. Yonezawa, T. Tajima, T. Sakamoto, H. Hamada, E. Chosa. Copy number loss in the region of the ASPN gene in patients with acetabular dysplasia: ASPN CNV in acetabular dysplasia. Bone Joint Res 2017;6:439–445. DOI: 10.1302/2046-3758.67.BJR-2016-0094.R1

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

We followed up 76 consecutive hips with symptomatic acetabular dysplasia treated by acetabular shelf augmentation for a mean period of 11 years. Survival analysis using conversion to hip replacement as an end-point was 86% at five years and 46% at ten years. Forty-four hips with slight or no narrowing of the joint space pre-operatively had a survival of 97% at five and 75% at ten years. This was significantly higher (p = 0.0007) than that of the 32 hips with moderate or severe narrowing of the joint-space, which was 76% at five and 22% at ten years. There was no significant relationship between survival and age (p = 0.37) or the pre- and post-operative centre-edge (p = 0.39) and acetabular angles (p = 0.85). Shelf acetabuloplasty is a reliable, safe procedure offering medium-term symptomatic relief for adults with acetabular dysplasia. The best results were achieved in patients with mild and moderate dysplasia of the hip with little arthritis

Aims. Some patients presenting with hip pain and instability and underlying acetabular dysplasia (AD) do not experience resolution of symptoms after surgical management. Hip-spine syndrome is a possible underlying cause. We hypothesized that there is a higher frequency of radiological spine anomalies in patients with AD. We also assessed the relationship between radiological severity of AD and frequency of spine anomalies. Methods. In a retrospective analysis of registry data, 122 hips in 122 patients who presented with hip pain and and a final diagnosis of AD were studied. Two observers analyzed hip and spine variables using standard radiographs to assess AD. The frequency of lumbosacral transitional vertebra (LSTV), along with associated Castellvi grade, pars interarticularis defect, and spinal morphological measurements were recorded and correlated with radiological severity of AD. Results. Out of 122 patients, 110 (90.2%) were female and 12 (9.8%) were male. We analyzed the radiographs of 122 hips (59 (48.4%) symptomatic left hips, and 63 (51.6%) symptomatic right hips). Average age at time of presentation was 34.2 years (SD 11.2). Frequency of LSTV was high (39% to 43%), compared to historic records from the general population, with Castellvi type 3b being the most common (60% to 63%). Patients with AD have increased L4 and L5 interpedicular distance compared to published values. Frequency of pars interarticularis defect was 4%. Intraclass correlation coefficient for hip and spine variables assessed ranged from good (0.60 to 0.75) to excellent (0.75 to 1.00). Severity of AD did not demonstrate significant correlation with frequency of radiological spine anomalies. Conclusion. Patients with AD have increased frequency of spinal anomalies seen on standard hip radiographs. However, there exists no correlation between radiological severity of AD and frequency of spine anomalies. In managing AD patients, clinicians should also assess spinal anomalies that are easily found on standard hip radiographs. Cite this article: Bone Joint J 2021;103-B(8):1351–1357

Aims. Acetabular dysplasia is frequently associated with intra-articular pathology such as labral tears, but whether labral tears should be treated at the time of periacetabular osteotomy (PAO) remains controversial. The purpose of this study was to compare the clinical outcomes and radiographic corrections of PAO for acetabular dysplasia between patients with and without labral tears pre-operatively. Patients and Methods. We retrospectively reviewed 70 hips in 67 patients with acetabular dysplasia who underwent PAO. Of 47 hips (45 patients) with labral tears pre-operatively, 27 (25 patients) underwent PAO alone, and were classified as the labral tear alone (LT) group, and 20 (20 patients) underwent combined PAO and osteochondroplasty, and were classified as the labral tear osteochondroplasty (LTO) group. The non-labral tear (NLT) group included 23 hips in 22 patients. Results. There were no significant differences between groups for post-operative Harris hip scores, degree of progression of osteoarthritis or rate of reoperation. The pre-operative alpha angle was significantly larger in the LTO group compared with the other groups (p < 0.0001). Conclusion. PAO provides equivalent short-term relief of pain and functional outcome in patients with or without labral tears. The rate of progression of osteoarthritis and reoperation was not significantly increased in patients with labral tears. Take home message: PAO provides equivalent short-term pain relief and functional outcomes in patients with acetabular dysplasia with and without labral tears. We did not find significantly increased risks of progression of osteoarthritis or re-operation in those with labral tears. Cite this article: Bone Joint J 2016;98-B:741–6

Our aim was to determine whether abnormalities noted on MRI immediately after reduction for developmental dysplasia of the hip could predict the persistance of dysplasia and aid surgical planning. Scans of 13 hips in which acetabular dysplasia had resolved by the age of four years were compared with those of five which had required pelvic osteotomy for persisting dysplasia. The scans were analysed by two consultant musculoskeletal radiologists who were blinded to the outcome in each child. The postreduction scans highlighted a number of anatomical abnormalities secondary to developmental dysplasia of the hip, but statistical analysis showed that none were predictive of persisting acetabular dysplasia in the older child, suggesting that the factors which determine the long-term outcome were not visible on these images

We describe a new technique of reconstruction of the deficient acetabulum in cementless total hip arthroplasty. The outer iliac table just above the deficient acetabulum is osteotomised and slid downwards. We have termed this an iliac sliding graft. Between October 1997 and November 2001, cementless total hip arthroplasty with an iliac sliding graft was performed on 19 patients (19 hips) with acetabular dysplasia. The mean follow-up was 3.4 years (2 to 6). The mean pre-operative Harris hip score was 45.1 which improved significantly to 85.3 at the time of the final follow-up. No patient had post-operative abductor dysfunction. Incorporation of the graft was seen after two to three months in all patients. Resorption of the graft and radiolucencies were infrequent. This technique is a useful alternative to femoral head autografting when the patient’s own femoral head cannot be used

Hereditary multiple exostoses is an autosomal dominant disorder characterised by multiple osteochondromata, most commonly affecting the forearm, knee and ankle. Osteochondromata of the proximal femur have been reported to occur in 30% to 90% of affected patients with coxa valga in 25%. Acetabular dysplasia is rare but has been described. This is the first report of a patient requiring surgical intervention. A girl was seen at the age of nine with hereditary multiple exostoses and when 12 developed bilateral pain in the groin. Radiographs showed severely dysplastic acetabula with less than 50% coverage of the femoral heads and widening of the medial joint space. Large sessile osteochondromata were present along the medial side of the femoral neck proximal to the lesser trochanter, with associated coxa valga. The case illustrates the importance of obtaining initial skeletal surveys in children with hereditary multiple exostoses to identify potential problems such as acetabular dysplasia and subluxation of the hip

Aims. There has been limited literature regarding outcomes of acetabular rim syndrome (ARS) with persistent acetabular os in the setting of acetabular dysplasia. The purpose of this study was to characterize a cohort of adolescent and young adult patients with ARS with persistent os and compare their radiological and clinical outcomes to patients with acetabular dysplasia without an os. Methods. We reviewed a prospective database of patients undergoing periacetabular osteotomy (PAO) for symptomatic acetabular dysplasia between January 1999 and December 2021 to identify hips with preoperative os acetabuli, defined as a closed triradiate cartilage but persistence of a superolateral os acetabulum. A total of 14 hips in 12 patients with persistent os acetabuli (ARS cohort) were compared to 50 randomly selected ‘control’ hips without persistent os acetabuli. Preoperative and postoperative radiographs were measured for markers of dysplasia: lateral centre-edge angle, anterior centre-edge angle, acetabular inclination, and migration index. Union of the os was determined in patients with ≥ six months’ follow-up. Patient-reported outcome measures (PROMs) included the University of California, Los Angeles (UCLA) activity score and modified Harris Hip Score (mHHS, maximum score 80) completed at one year postoperatively. Results. There was no significant difference between the ARS and control cohorts with regard to sex distribution (p = 0.270), age at surgery (p = 0.186), or BMI (p = 0.442). Preoperatively, the ARS cohort had more severe dysplasia, including lower lateral centre-edge angle (-9.3° (SD 12.5°) vs 7.6° (SD 10.7°); p < 0.001) and greater acetabular inclination (33.9° (SD 8.2°) vs 21.8° (SD 8.7°); p < 0.001). Postoperatively, 6/13 (46%) hips with ≥ six months of radiological follow up demonstrated union of the os. There was no difference between the ARS and control cohorts at one year in UCLA score (9.1 (SD 1.5) vs 8.2 (SD 1.9); p = 0.167) or mHHS (73.4 (SD 9.5) vs 69.9 (SD 8.8); p = 0.312). Conclusion. ARS with persistent acetabular os may occur in more severe dysplasia. Union occurs in 50% cases following corrective PAO. Cite this article: Bone Joint J 2024;106-B(12):1393–1398

1. A survey of genetic and other etiological factors has been carried out in 589 index patients with congenital dislocation of the hip and their families, with special investigation of acetabular dysplasia, familial joint laxity and a comparison of neonatal and late-diagnosis cases. 2. It is believed that there are two etiological groups with congenital dislocation of the hip, i) a group with acetabular dysplasia which is inherited as a multiple gene system and is responsible for a high proportion of cases diagnosed late, and ii) a group with joint laxity which is responsible for a high proportion of neonatal cases. 3. Evidence is presented to show that acetabular dysplasia is a separate heritable system in some families. 4. Other findings relating to the genetic aspects of the survey are summarised

The October 2024 Children’s orthopaedics Roundup. 360. looks at: Cost-effectiveness analysis of soft bandage and immediate discharge versus rigid immobilization in children with distal radius torus fractures: the FORCE trial; Percutaneous Achilles tendon tenotomy in clubfoot with a blade or a needle: a single-centre randomized controlled noninferiority trial; Treatment of hip displacement in children with cerebral palsy: a five-year comparison of proximal femoral osteotomy and combined femoral-pelvic osteotomy in 163 children; The Core outcome Clubfoot (CoCo) study: relapse, with poorer clinical and quality of life outcomes, affects 37% of idiopathic clubfoot patients; Retention versus removal of epiphyseal screws in paediatric distal tibial fractures: no significant impact on outcomes; Predicting the resolution of residual acetabular dysplasia after brace treatment in infant DDH; Low prevalence of acetabular dysplasia following treatment for neonatal hip instability: a long-term study; How best to distract the patient?

Fifty-one infants with limited abduction of the hip and acetabular dysplasia were, between 1969 and 1975, treated with abduction-adduction exercises, administered by the parents; no abduction devices were used. In 1983 a follow-up examination was carried out on 41 of these patients. Although at birth these children had characteristics similar to patients with congenital dislocation of the hip, none of their hips dislocated. At birth acetabular measurements showed that half the children had severe dysplasia and the other half slight dysplasia; the difference between the affected and the healthy hips was significant. At follow-up the gait was normal in all the patients. Movements at the hips were symmetrical and within normal limits in all but one patient. The acetabular angle, the centre-edge angle, the shaft-neck angle, the hip ratio, and the size of the femoral head were the same on the previously affected side as on the normal side. Nineteen of the children followed up had preferred lying on one side and dysplasia of the upper hip had developed. The significance of the sleeping position on the development of acetabular dysplasia is discussed

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

Reorientation of the acetabulum may be required in adolescents and young adults with developmental dysplasia of the hip. We have carried out a retrospective review of 51 hips after triple osteotomy with an average follow-up of ten years (8 to 15). Forty-eight hips (94%) were available for review and of these 39 (81%) were improved compared with before operation, 29 (60%) scoring good or excellent. Radiographic assessment showed improvement of the average centre-edge angle by 19°, the acetabular index by 12° and the anterior centre-edge angle by 26°. The degree of osteoarthritis progressed by one grade in ten hips (21%) over a period of ten years. The satisfactory long-term clinical and radiographic results have encouraged us to continue this treatment for symptomatic acetabular dysplasia in these patients

Between 1986 and 1990, we carried out 55 rotational acetabular osteotomies in 54 patients with acetabular dysplasia. Five hips were lost to follow-up. Of the 50 remaining, the degenerative changes were classified according to the criteria of Tönnis as grade 0 in 23, grade 1 in 16 and grade 2 in 11. The mean age of the three men and 46 women at the time of operation was 31.8 years (13 to 53). The mean follow-up was 137 months (120 to 174). At the most recent follow-up, 48 patients had satisfactory relief from pain. There was a slight decrease in the range of movement, particularly of flexion, in 18 hips. Radiologically, all osteotomies had united satisfactorily. There was radiological evidence of improvement in degenerative changes in 13 hips (5 grade 1 and 8 grade 2). Ten deteriorated (5 grade 0, 3 grade 1, and 2 grade 2) and one required total hip arthroplasty ten years after osteotomy. The osteoarthritis in the two hips with an associated valgus osteotomy progressed. The changes in radiological indices such as the centre-edge angle, acetabular femoral head index, acetabular root obliquity and horizontal or vertical displacement of the femoral head showed no statistical difference (unpaired Student’s t-test) between the patients with radiological progression and those with and without improvement

Untreated acetabular dysplasia following treatment for developmental dysplasia of the hip (DDH) leads to early degenerative joint disease. Clinicians must accurately and reliably recognise dysplasia in order to intervene appropriately with secondary acetabular or femoral procedures. This study sought early predictors of residual dysplasia in order to establish empirically-based indications for treatment. DDH treated by closed or open reduction alone was reviewed. Residual hip dysplasia was defined according to the Severin classification at skeletal maturity. Future hip replacement in a subset of these patients was compared with the Severin classification. Serial measurements of acetabular development and subluxation of the femoral head were collected, as were the age at reduction, type of reduction, and Tonnis grade prior to reduction. These variables were used to predict the Severin classification. The mean age at reduction in 72 hips was 16 months (1 to 46). On the final radiograph, 47 hips (65%) were classified as Severin I/II, and 25 as Severin III/IV (35%). At 40 years after reduction, five of 43 hips (21%) had had a total hip replacement (THR). The Severin grade was predictive for THR. Early measurements of the acetabular index (AI) were predictive for Severin grade. For example, an AI of 35° or more at two years after reduction was associated with an 80% probability of becoming a Severin grade III/IV hip. This study links early acetabular remodelling, residual dysplasia at skeletal maturity and the long-term risk of THR. It presents evidence describing the diagnostic value of early predictors of residual dysplasia, and therefore, of the long-term risk of degenerative change

1. The results of Chiari pelvic osteotomy have been examined two to six years after operation in a group of eighteen patients with persisting acetabular dysplasia in the second and third decades. 2. The analysis suggests that for a good clinical result it is essential to create a relationship of the new outer acetabular lip to the original lip so that the CE angle is between 20 and 40 degrees and the roof angle is between 10 degrees below and 20 degrees above the horizontal. 3. This may be achieved by a pelvic osteotomy immediately above the joint capsule, angled 10 degrees upwards and inwards and displaced by 50 per cent of the pelvic thickness. 4. Details of the operative technique using a Smith-Petersen approach are presented

We carried out a morphometric analysis of acetabular dysplasia in patients with cerebral palsy requiring hip surgery using three-dimensional CT. We evaluated 54 hips in 27 patients. The contralateral normal hips of ten patients with unilateral Perthes’ disease were used as a control group. The acetabular defects were assessed qualitatively as anterior, posterior or global. Quantitative assessments were made using three-directional acetabular indices (anterosuperior, superolateral and posterosuperior) and measured by multiplanar reformation, from which we calculated the acetabular volume. In the qualitative study, posterior defects were most common in the subluxation group whereas global defects predominated in the dislocation group. In the quantitative study, all acetabular indices in both the subluxation and dislocation groups were higher than those in the control group and the superolateral indices showed a tendency to elevation in the dislocation group. The acetabular volume was largest in the control group, smallest in the dislocation group, and intermediate between the two in the subluxation group