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. To assess if congenital foot deformity is a risk factor for developmental dysplasia of the hip (DDH). Methods. Between 1996 and 2012, 60,844 children were born in Sør-Trøndelag county in Norway. In this cohort study, children with risk factors for DDH were examined using ultrasound. The risk factors evaluated were clinical hip instability, breech delivery, a family history of DDH, a foot deformity, and some syndromes. As the aim of the study was to examine the risk for DDH and foot deformity in the general population, children with syndromes were excluded. The information has been prospectively registered and retrospectively analyzed. Results. Overall, 494 children (0.8%) had DDH, and 1,132 (1.9%) a foot deformity. Of the children with a foot deformity, 49 (4.3%) also demonstrated DDH. There was a statistically significant increased association between DDH and foot deformity (p < 0.001). The risk of DDH was highest for talipes calcaneovalgus (6.1%) and club foot (3.5%), whereas metatarsus adductus (1.5%) had a marginal increased risk of DDH. Conclusion. Compared with the general population, children with a congenital foot deformity had a significantly increased risk for DDH and therefore we regard foot deformity as a true risk factor for DDH. Cite this article: Bone Joint J 2020;102-B(11):1582–1586

Aims. To monitor the performance of services for developmental dysplasia of the hip (DDH) in Northern Ireland and identify potential improvements to enhance quality of service and plan for the future. Methods. This was a prospective observational study, involving all infants treated for DDH between 2011 and 2017. Children underwent clinical assessment and radiological investigation as per the regional surveillance policy. The regional radiology data was interrogated to quantify the use of ultrasound and ionizing radiation for this population. Results. Evidence-based changes were made to the Northern Ireland screening programme, including an increase in ultrasound scanning capacity and expansion of nurse-led screening clinics. The number of infant hip ultrasound scans increased from 4,788 in 2011, to approximately 7,000 in 2013 and subsequent years. The number of hip radiographs on infants of less than one year of age fell from 7,381 to 2,208 per year. There was a modest increase in the treatment rate from 10.9 to 14.3 per 1,000 live births but there was a significant reduction in the number of closed hip reductions. The incidence of infants diagnosed with DDH after one year of age was 0.30 per 1,000 live births over the entire period. Conclusion. Improving compliance with the regional infant hip screening protocols led to reduction in operative procedures and reduced the number of pelvic radiographs of infants. We conclude that performance monitoring of screening programmes for DDH is essential to provide a quality service. Cite this article: Bone Joint J 2020;102-B(4):495–500

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. The aim of this study was to identify the association between asymmetrical skin creases of the thigh, buttock or inguinal region and pathological developmental dysplasia of the hip (DDH). Patients and Methods. Between 1 January 1996 and 31 December 2016, all patients referred to our unit from primary or secondary care with risk factors for DDH were assessed in a “one stop” clinic. All had clinical and sonographic assessment by the senior author (RWP) with the results being recorded prospectively. The inclusion criteria for this study were babies and children referred with asymmetrical skin creases. Those with a neurological cause of DDH were excluded. The positive predictive value (PPV) for pathological DDH was calculated. Results. A total of 105 patients met the inclusion criteria. There were 71 girls and 34 boys. Only two were found to have pathological DDH. Both also had unilateral limited abduction of the hip in flexion and a positive Galeazzi sign with apparent leg-length discrepancy. Thus, if the specialist examination of a patient with asymmetrical skin creases was normal, the PPV for DDH was 0%. Conclusion. Isolated asymmetrical skin creases are an unreliable clinical sign in the diagnosis of pathological DDH. Greater emphasis should be placed on the presence of additional clinical signs to guide radiological screening in babies and children. Cite this article: Bone Joint J 2018;100-B:675–9

Aims. There is no consensus regarding optimum timing and frequency of ultrasound (US) for monitoring response to Pavlik harness (PH) treatment in developmental dysplasia of the hip (DDH). The purpose of our study was to determine if a limited-frequency hip US assessment had an adverse effect on treatment outcomes compared to traditional comprehensive US monitoring. Methods. This study was a single-centre noninferiority randomized controlled trial. Infants aged under six months whose hips were reduced and centred in the harness at initiation of treatment (stable dysplastic or subluxable), or initially decentred (subluxated or dislocated) but reduced and centred within four weeks of PH treatment, were randomized to our current standard US monitoring protocol (every clinic visit) or to a limited-frequency US protocol (US only at end of treatment). Groups were compared based on α angle and femoral head coverage at the end of PH treatment, acetabular indices, and International Hip Dysplasia Institute (IHDI) grade on one-year follow-up radiographs. Results. Overall, 100 patients were included; 42 patients completed the standard protocol (SP) and 40 completed the limited protocol (LP). There was no significant difference in mean right α angle at the end of treatment (SP 70.0° (SD 3.2°) ; LP 68.7° (SD 2.9°); p = 0.033), nor on the left (SP 69.0° (SD 3.5°); LP 68.1° (SD 3.3°); p = 0.128). There was no significant difference in mean right acetabular index at follow-up (SP 23.1° (SD 4.3°); LP 22.0° (SD 4.1°); p = 0.129), nor on the left (SP 23.3° (SD 4.2°); LP 22.8° (SD 3.9°); p = 0.284). All hips had femoral head coverage of > 50% at end of treatment, and all were IHDI grade 1 at follow-up. In addition, the LP group underwent a 60% reduction in US use once stable. Conclusion. Our study supports reducing the frequency of US assessment during PH treatment of DDH once a hip is reduced and centred. Cite this article: Bone Joint J 2022;104-B(9):1081–1088

Aims. The significance of the ‘clicky hip’ in neonatal and infant examination remains controversial with recent conflicting papers reigniting the debate. We aimed to quantify rates of developmental dysplasia of the hip (DDH) in babies referred with ‘clicky hips’ to our dedicated DDH clinic. Patients and Methods. A three-year prospective cohort study was undertaken between 2014 and 2016 assessing the diagnosis and treatment outcomes of all children referred specifically with ‘clicky hips’ as the primary reason for referral to our dedicated DDH clinic. Depending on their age, they were all imaged with either ultrasound scan or radiographs. Results. There were 69 ‘clicky hip’ referrals over the three-year period. This represented 26.9% of the total 257 referrals received in that time. The mean age at presentation was 13.6 weeks (1 to 84). A total of 19 children (28%) referred as ‘clicky hips’ were noted to have hip abnormalities on ultrasound scan, including 15 with Graf Type II hips (7 bilateral), one Graf Type III hip, and three Graf Type IV hips. Of these, ten children were treated with a Pavlik harness, with two requiring subsequent closed reduction in theatre; one child was treated primarily with a closed reduction and adductor tenotomy. In total, 11 (15.9%) of the 69 ‘clicky hip’ referrals required intervention with either harness or surgery. Conclusion. Our study provides further evidence that the ‘clicky hip’ referral can represent an underlying diagnosis of DDH and should, in our opinion, always lead to further clinical and radiological assessment. In the absence of universal ultrasound screening, we would encourage individual units to carefully assess their own outcomes and protocols for ‘clicky hip’ referrals and tailor ongoing service provision to local populations and local referral practices. Cite this article: Bone Joint J 2018;100-B:1249–52

The term developmental dysplasia of the hip (DDH) describes a spectrum of disorders that results in abnormal development of the hip joint. If not treated successfully in childhood, these patients may go on to develop hip symptoms and/or secondary osteoarthritis in adulthood. In this review we describe the altered anatomy encountered in adults with DDH along with the management options, and the challenges associated with hip arthroscopy, osteotomies and arthroplasty for the treatment of DDH in young adults. Cite this article: Bone Joint J 2013;95-B:732–7

The purpose of this study was to investigate the development of the osseous acetabular index (OAI) and cartilaginous acetabular index (CAI) using MRI. The OAI and CAI were measured on the coronal MR images of the hip in 81 children with developmental dysplasia of the hip (DDH), with a mean age of 19.6 months (3 to 70), and 241 normal control children with a mean age of 5.1 years (1 month to 12.5 years). Additionally the developmental patterns of the OAI and CAI in normal children were determined by age-based cross-sectional analysis. Unlike the OAI, the normal CAI decreased rapidly from a mean of 10.17° (. sd. 1.60) to a mean of 8.25° (. sd. 1.90) within the first two years of life, and then remained constant at a mean of 8.04° (. sd. 1.65) until adolescence. Although no difference in OAI was found between the uninvolved hips in children with unilateral DDH and normal hips (p = 0.639), the CAI was significantly different between them both (p < 0.001). The normal CAI has fully formed at birth, and is maintained constantly throughout childhood. The CAI in the unaffected hips in children with unilateral DDH is also mildly dysplastic

In developmental dysplasia of the hip (DDH), a bone defect is often observed superior to the acetabulum after the reconstruction at the level of the true acetabulum during total hip replacement (THR). However, the essential amount of uncemented acetabular component coverage required for a satisfactory outcome remains controversial. The purpose of this study was to assess the stability and function of acetabular components with a lack of coverage > 30% (31% to 50%). A total of 760 DDH patients underwent THR with acetabular reconstruction at the level of the true floor. Lack of coverage above the acetabular component of > 30% occurred in 56 patients. Intra-operatively, autogenous morcellised bone grafts were used to fill the uncovered portion. Other than two screws inserted through the acetabular shell, no additional structural supports were used in these hips. In all, four patients were lost to follow-up. Therefore, 52 patients (52 hips, 41 women and 11 men) with a mean age of 60.1 years (42 to 78) were available for this study at a mean of 4.8 years (3 to 7). There were no instances of prosthesis revision or marked loosening during the follow-up. The Harris hip score improved from a mean of 40.7 points (. sd. 12.2) pre-operatively to 91.1 (. sd. 5.0) at the last follow-up. Radiological analysis with medical imaging software allowed us to calculate the extent of the uncoverage in terms of the uncovered arc of the implant as viewed on the anteroposterior pelvic radiograph. From this we propose that up to 17 mm of lateral undercoverage in the presence of a stable initial implantation in the presence of bone autografting, with an inclination angle of the acetabular component between 40° and 55°, is acceptable. This represents undercoverage of ≤ 50%. Cite this article: Bone Joint J 2013;95-B:1178–83

Successful management of late presenting hip dislocation in childhood is judged by the outcome not just at skeletal maturity but well beyond into adulthood and late middle age. This review considers different methods of treatment and looks critically at the handful of studies reporting long-term follow-up after successful reduction.

Cite this article: Bone Joint J 2015;97-B:729–33.

We describe the clinical and radiological results of cementless primary total hip replacement (THR) in 25 patients (18 women and seven men; 30 THRs) with severe developmental dysplasia of the hip (DDH). Their mean age at surgery was 47 years (23 to 89). In all, 21 hips had Crowe type III dysplasia and nine had Crowe type IV. Cementless acetabular components with standard polyethylene liners were introduced as close to the level of the true acetabulum as possible. The modular cementless S-ROM femoral component was used with a low resection of the femoral neck.

A total of 21 patients (25 THRs) were available for review at a mean follow-up of 18.7 years (15.8 to 21.8). The mean modified Harris hip score improved from 46 points pre-operatively to 90 at final follow up (p < 0.001).

A total of 15 patients (17 THRs; 57%) underwent revision of the acetabular component at a mean of 14.6 years (7 to 20.8), all for osteolysis. Two patients (two THRs) had symptomatic loosening. No patient underwent femoral revision. Survival with revision of either component for any indication was 81% at 15 years (95% CI 60.1 to 92.3), with 21 patients at risk.

This technique may reduce the need for femoral osteotomy in severe DDH, while providing a good long-term functional result.

Cite this article: Bone Joint J 2014;96-B:1449–54.

Aims. To analyze whether the addition of risk-based criteria to clinical examination-based selective ultrasound screening would increase the rates of early detected cases of developmental dysplasia of the hip (DDH) and decrease the rate of late detected cases. Methods. A systematic review with meta-analysis was performed. The initial search was performed in the PubMed, Scopus, and Web of Science databases in November 2021. The following search terms were used: (hip) AND (ultrasound) AND (luxation or dysplasia) AND (newborn or neonate or congenital). Results. A total of 25 studies were included. In 19 studies, newborns were selected for ultrasound based on both risk factors and clinical examination. In six studies, newborns were selected for ultrasound based on only clinical examination. We did not find evidence indicating that there are differences in the incidence of early- and late-detected DDH, or in the incidence of nonoperatively treated DDH between the risk-based and clinical examination-based groups. The pooled incidence of operatively treated DDH was slightly lower in the risk-based group (0.5 (95% confidence interval (CI) 0.3 to 0.7)) compared with the clinical examination group (0.9 per 1,000 newborns, (95% CI 0.7 to 1.0)). Conclusion. The use of risk factors in conjunction with clinical examination in the selective ultrasound screening of DDH might lead to fewer operatively treated cases of DDH. However, more studies are needed before stronger conclusions can be drawn. Cite this article: Bone Joint J 2023;105-B(3):247–253

Most centres in the United Kingdom adopt a selective screening programme for developmental dysplasia of the hip (DDH) based on repeated clinical examination and selective ultrasound examination. The Newborn Infant Physical Examination protocol implemented in 2008 recommends a first examination at birth and then a second and final examination at six to ten weeks of age. Due to concerns over an increase in late presentations we performed a retrospective review of our 15-year results to establish if late presentation increases treatment requirements. Of children presenting before six weeks of age, 84% were treated successfully with abduction bracing, whereas 86% of children presenting after ten months eventually required open reduction surgery. This equates to a 12-fold increase in relative risk of requiring open reduction following late presentation. Increasing age at presentation was associated with an increase in the number of surgical procedures, which are inevitably more extensive and complex, with a consequent increased in cost per patient. The implementation of an opportunistic examination at three to five months could help to reduce the unintended consequences of the Newborn Infant Physical Examination programme.

Cite this article: Bone Joint J 2013;95-B:846–50.

The medial approach for the treatment of children with developmental dysplasia of the hip (DDH) in whom closed reduction has failed requires minimal access with negligible blood loss. In the United Kingdom, there is a preference for these children to be treated using an anterolateral approach after the appearance of the ossific nucleus. In this study we compared these two protocols, primarily for the risk of osteonecrosis.

Data were gathered prospectively for protocols involving the medial approach (26 hips in 22 children) and the anterolateral approach (22 hips in 21 children) in children aged <  24 months at the time of surgery. Osteonecrosis of the femoral head was assessed with validated scores. The acetabular index (AI) and centre–edge angle (CEA) were also measured.

The mean age of the children at the time of surgery was 11 months (3 to 24) for the medial approach group and 18 months (12 to 24) for the anterolateral group, and the combined mean follow-up was 70 months (26 to 228). Osteonecrosis of the femoral head was evident or asphericity predicted in three of 26 hips (12%) in the medial approach group and four of 22 (18%) in the anterolateral group (p = 0.52). The mean improvement in AI was 8.8° (4° to 12°) and 7.9° (6° to 10°), respectively, at two years post-operatively (p = 0.18). There was no significant difference in CEA values of affected hips between the two groups.

Children treated using an early medial approach did not have a higher risk of developing osteonecrosis at early to mid-term follow-up than those treated using a delayed anterolateral approach. The rates of acetabular remodelling were similar for both protocols.

Cite this article: Bone Joint J 2014;96-B:406–13.

Several authors have suggested that the final five weeks of gestation are a critical period for the development of the hip. In order to test the hypothesis that gestational age at birth may influence the development of the hip joint, we analysed the sonographic findings in 1992 hips (in 996 term newborns) with no risk factor for developmental dysplasia of the hip. The 996 infants were born at a mean gestational age of 39 weeks (37 to 41).

The mean bony roof angle (α), cartilage roof angle (β) and the distribution of the type of hip were compared between the 37th, 38th, 39th, 40th and 41st birth week groups. There was a significant difference in the distribution of type of hip between the different birth week groups (p < 0.001), but no significant difference between the α angles of all groups (p = 0.32). There was no correlation between birth week and roof angle (p = 0.407 and p = 0.291, respectively) and no significant correlation between birth weight and roof angle (p = 0.735 and p = 0.132, respectively).

The maturity of the infant hip, as assessed sonographically, does not appear to be affected by gestational age, and the fetal development of the acetabular roof appears to plateau from 37 weeks.

Cite this article: Bone Joint J 2013;95-B:266–70.

We report the use of a 15° face-changing cementless acetabular component in patients undergoing total hip replacement for osteoarthritis secondary to developmental dysplasia of the hip. The rationale behind its design and the surgical technique used for its implantation are described. It is distinctly different from a standard cementless hemispherical component as it is designed to position the bearing surface at the optimal angle of inclination, that is, < 45°, while maximising the cover of the component by host bone.

Aims. We investigated the prevalence of late developmental dysplasia of the hip (DDH), abduction bracing treatment, and surgical procedures performed following the implementation of universal ultrasound screening versus selective ultrasound screening programmes. Methods. A systematic search of PubMed, Embase, The Cochrane Library, OrthoSearch, and Web of Science from the date of inception of each database until 27 March 2022 was performed. The primary outcome of interest was the prevalence of late detection of DDH, diagnosed after three months. Secondary outcomes of interest were the prevalence of abduction bracing treatment and surgical procedures performed in childhood for dysplasia. Only studies describing the primary outcome of interest were included. Results. A total of 31 studies were identified, of which 13 described universal screening and 20 described selective screening. Two studies described both. The prevalence of late DDH was 0.10 per 1,000 live births (95% confidence interval (CI) 0.00 to 0.39) in the universal screening group and 0.45 per 1,000 live births (95% CI 0.31 to 0.61) in the selective screening group. Abduction bracing treatment was performed on 55.54 per 1,000 live births (95% CI 24.46 to 98.15) in the universal screening group versus 0.48 per 1,000 live births (95% CI 0.07 to 1.13) in the selective screening group. Both the universal and selective screening groups had a similar prevalence of surgical procedures in childhood for dysplasia being performed (0.48 (95% CI 0.32 to 0.63) vs 0.49 (95% CI 0.31 to 0.71) per 1,000 live births, respectively). Conclusion. Universal screening showed a trend towards lower prevalence of late DDH compared to selective screening. However, it was also associated with a significant increase in the prevalence of abduction bracing without a significant reduction in the prevalence of surgical procedures in childhood for dysplasia being performed. High-quality studies comparing both treatment methods are required, in addition to studies into the natural history of missed DDH. Cite this article: Bone Joint J 2023;105-B(2):198–208

Aims. Developmental dysplasia of the hip (DDH) describes a pathological relationship between the femoral head and acetabulum. Periacetabular osteotomy (PAO) may be used to treat this condition. The aim of this study was to evaluate the results of PAO in adolescents and adults with persistent DDH. Methods. Patients were divided into four groups: A, adolescents who had not undergone surgery for DDH in childhood (25 hips); B, adolescents who had undergone surgery for DDH in childhood (20 hips); C, adults with DDH who had not undergone previous surgery (80 hips); and D, a control group of patients with healthy hips (70 hips). The radiological evaluation of digital anteroposterior views of hips included the Wiberg angle (centre-edge angle (CEA)), femoral head cover (FHC), medialization, distalization, and the ilioischial angle. Clinical assessment involved the Harris Hip Score (HHS) and gluteal muscle performance assessment. Results. Significant improvements in radiological parameters were achieved in all measurements in all groups (p < 0.05). The greatest improvement was in CEA (mean of 19° (17.2° to 22.3°) in Group B), medialization (mean of 3 mm (0.9 to 5.2) in Group C), distalization (mean of 6 mm (3.5 to 8.2) in Group B), FHC (mean of 17% (12.7% to 21.2%) in Group B), and ilioischial angle (mean of 5° (2.3° to 8.1°) in Group B). There were significant improvements in the mean HHS and gluteal muscle performance scores postoperatively in all three groups. Conclusion. The greatest correction of radiological parameters and clinical outcomes was found in patients who had undergone hip surgery in childhood. Although the surgical treatment of DDH in childhood makes subsequent hip surgery more difficult due to scarring, adhesions, and altered anatomy, it requires less correction of the deformity and has a beneficial effect on the outcome of PAO in adolescence and early adulthood. Cite this article: Bone Joint J 2022;104-B(7):775–780

We present our early experience of arthroscopic reduction of the dislocated hip in very young infants with developmental dysplasia of the hip (DDH).

Eight dislocated hips, which had failed attempts at closed reduction, were treated by arthroscopy of the hip in five children with a mean age of 5.8 months (4 to 7). A two-portal technique was used, with a medial sub-adductor portal for a 2.7 mm cannulated system with a 70° arthroscope and an anterolateral portal for the instruments. Following evaluation of the key intra-articular structures, the hypertrophic ligamentum teres and acetabular pulvinar were resected, and a limited release of the capsule was performed prior to reduction of the hip. All hips were reduced by a single arthroscopic procedure, the reduction being confirmed on MRI scan. None of the hips had an inverted labrum. The greatest obstacle to reduction was a constriction of the capsule. At a mean follow-up of 13.2 months (9 to 24), all eight hips remained stable. Three developed avascular necrosis. The mean acetabular index decreased from 35.5° (30° to 40°) pre-operatively to 23.3° (17° to 28°).

This study demonstrates that arthroscopic reduction is feasible using two standardised portals. Longer follow-up studies are necessary to evaluate the functional results.

Aims. A national screening programme has existed in the UK for the diagnosis of developmental dysplasia of the hip (DDH) since 1969. However, every aspect of screening and treatment remains controversial. Screening programmes throughout the world vary enormously, and in the UK there is significant variation in screening practice and treatment pathways. We report the results of an attempt by the British Society for Children’s Orthopaedic Surgery (BSCOS) to identify a nationwide consensus for the management of DDH in order to unify treatment and suggest an approach for screening. Methods. A Delphi consensus study was performed among the membership of BSCOS. Statements were generated by a steering group regarding aspects of the management of DDH in children aged under three months, namely screening and surveillance (15 questions), the technique of ultrasound scanning (eight questions), the initiation of treatment (19 questions), care during treatment with a splint (ten questions), and on quality, governance, and research (eight questions). A two-round Delphi process was used and a consensus document was produced at the final meeting of the steering group. Results. A total of 60 statements were graded by 128 clinicians in the first round and 132 in the second round. Consensus was reached on 30 out of 60 statements in the first round and an additional 12 in the seond. This was summarized in a consensus statement and distilled into a flowchart to guide clinical practice. Conclusion. We identified agreement in an area of medicine that has a long history of controversy and varied practice. None of the areas of consensus are based on high-quality evidence. This document is thus a framework to guide clinical practice and on which high-quality clinical trials can be developed. Cite this article: Bone Joint J 2023;105-B(2):209–214

Aims. The objective of this study was to evaluate the clinical and radiological outcomes of patients younger than six months of age with developmental dysplasia of the hip (DDH) managed by either a Pavlik harness or Tübingen hip flexion splint. Methods. Records of 251 consecutive infants with a mean age of 89 days (SD 47), diagnosed with DDH between January 2015 and December 2018, were retrospectively reviewed. Inclusion criteria for patients with DDH were: younger than 180 days at the time of diagnosis; ultrasound Graf classification of IIc or greater; treatment by Pavlik harness or Tübingen splint; and no prior treatment history. All patients underwent hip ultrasound every seven days during the first three weeks of treatment and subsequently every three to four weeks until completion of treatment. If no signs of improvement were found after three weeks, the Pavlik harness or Tübingen splint was discontinued. Statistical analysis was performed. Results. The study included 251 patients with Graf grades IIc to IV in 18 males and 233 females with DDH. Mean follow-up time was 22 months (SD 10). A total of 116 hips were graded as Graf IIc (39.1%), nine as grade D (3.0%), 100 as grade III (33.7%), and 72 as grade IV (24.2%). There were 109 patients (128 hips) in the Pavlik group and 142 patients (169 hips) in the Tübingen group (p = 0.227). The Tübingen group showed a 69.8% success rate in Graf III and Graf IV hips while the success rate was significantly lower in the Pavlik group, 53.9% (p = 0.033). For infants older than three months of age, the Tübingen group showed a 71.4% success rate, and the Pavlik group a 54.4% success rate (p = 0.047). Conclusion. The Tübingen splint should be the preferred treatment option for children older than three months, and for those with severe forms of DDH such as Graf grade III and IV, who are younger than six months at time of diagnosis. The Tübingen hip flexion splint is a valid alternative to the Pavlik harness for older infants and those with more severe DDH. Cite this article: Bone Joint J 2021;103-B(5):991–998

Aims. Eccentric reductions may become concentric through femoral head ‘docking’ (FHD) following closed reduction (CR) for developmental dysplasia of the hip (DDH). However, changes regarding position and morphology through FHD are not well understood. We aimed to assess these changes using serial MRI. Methods. We reviewed 103 patients with DDH successfully treated by CR and spica casting in a single institution between January 2016 and December 2020. MRI was routinely performed immediately after CR and at the end of each cast. Using MRI, we described the labrum-acetabular cartilage complex (LACC) morphology, and measured the femoral head to triradiate cartilage distance (FTD) on the midcoronal section. A total of 13 hips with initial complete reduction (i.e. FTD < 1 mm) and ten hips with incomplete MRI follow-up were excluded. A total of 86 patients (92 hips) with a FTD > 1 mm were included in the analysis. Results. At the end of the first cast period, 73 hips (79.3%) had a FTD < 1 mm. Multiple regression analysis showed that FTD (p = 0.011) and immobilization duration (p = 0.028) were associated with complete reduction. At the end of the second cast period, all 92 hips achieved complete reduction. The LACC on initial MRI was inverted in 69 hips (75.0%), partly inverted in 16 hips (17.4%), and everted in seven hips (7.6%). The LACC became everted-congruent in 45 hips (48.9%) and 92 hips (100%) at the end of the first and second cast period, respectively. However, a residual inverted labrum was present in 50/85 hips (58.8%) with an initial inverted or partly inverted LACC. Conclusion. An eccentric reduction can become concentric after complete reduction and LACC remodelling following CR for DDH. Varying immobilization durations were required for achieving complete reduction. A residual inverted labrum was present in more than half of all hips after LACC remodelling. Cite this article: Bone Joint J 2023;105-B(2):140–147

Aims. Abduction bracing is commonly used to treat developmental dysplasia of the hip (DDH) following closed reduction and spica casting, with little evidence to support or refute this practice. The purpose of this study was to determine the efficacy of abduction bracing after closed reduction in improving acetabular index (AI) and reducing secondary surgery for residual hip dysplasia. Methods. We performed a retrospective review of patients treated with closed reduction for DDH at a single tertiary referral centre. Demographic data were obtained including severity of dislocation based on the International Hip Dysplasia Institute (IHDI) classification, age at reduction, and casting duration. Patients were prescribed no abduction bracing, part-time, or full-time wear post-reduction and casting. AI measurements were obtained immediately upon cast removal and from two- and four-year follow-up radiographs. Results. A total of 243 hips underwent closed reduction and 82% (199/243) were treated with abduction bracing. There was no difference between those treated with or without bracing with regard to sex, age at reduction, severity of dislocation, spica duration, or immediate post-casting AI (all p > 0.05). There was no difference in hips treated with or without abduction brace with regard to AI at two years post-reduction (32.4° (SD 5.3°) vs 30.9° (SD 4.6°), respectively; p = 0.099) or at four years post-reduction (26.4° (SD 5.2°) vs 25.4° (SD 5.1°), respectively; p = 0.231). Multivariate analysis revealed only IHDI grade predicted AI at two years post-reduction (p = 0.004). There was no difference in overall rate of secondary surgery for residual dysplasia between hips treated with or without bracing (32% vs 39%, respectively; p = 0.372). However, there was an increased risk of early secondary surgery (< two years post-reduction) in the non-braced group (11.4% vs 2.5%; p = 0.019). Conclusion. Abduction bracing following closed reduction for DDH treatment is not associated with decreased residual dysplasia at two or four years post-reduction but may reduce rates of early secondary surgery. A prospective study is indicated to provide more definitive recommendations. Cite this article: Bone Joint J 2023;105-B(12):1327–1332

Aims. The diagnosis of developmental dysplasia of the hip (DDH) is challenging owing to extensive variation in paediatric pelvic anatomy. Artificial intelligence (AI) may represent an effective diagnostic tool for DDH. Here, we aimed to develop an anteroposterior pelvic radiograph deep learning system for diagnosing DDH in children and analyze the feasibility of its application. Methods. In total, 10,219 anteroposterior pelvic radiographs were retrospectively collected from April 2014 to December 2018. Clinicians labelled each radiograph using a uniform standard method. Radiographs were grouped according to age and into ‘dislocation’ (dislocation and subluxation) and ‘non-dislocation’ (normal cases and those with dysplasia of the acetabulum) groups based on clinical diagnosis. The deep learning system was trained and optimized using 9,081 radiographs; 1,138 test radiographs were then used to compare the diagnoses made by deep learning system and clinicians. The accuracy of the deep learning system was determined using a receiver operating characteristic curve, and the consistency of acetabular index measurements was evaluated using Bland-Altman plots. Results. In all, 1,138 patients (242 males; 896 females; mean age 1.5 years (SD 1.79; 0 to 10) were included in this study. The area under the receiver operating characteristic curve, sensitivity, and specificity of the deep learning system for diagnosing hip dislocation were 0.975, 276/289 (95.5%), and 1,978/1,987 (99.5%), respectively. Compared with clinical diagnoses, the Bland-Altman 95% limits of agreement for acetabular index, as determined by the deep learning system from the radiographs of non-dislocated and dislocated hips, were -3.27° - 2.94° and -7.36° - 5.36°, respectively (p < 0.001). Conclusion. The deep learning system was highly consistent, more convenient, and more effective for diagnosing DDH compared with clinician-led diagnoses. Deep learning systems should be considered for analysis of anteroposterior pelvic radiographs when diagnosing DDH. The deep learning system will improve the current artificially complicated screening referral process. Cite this article: Bone Joint J 2020;102-B(11):1574–1581

Aims. Morphological abnormalities are present in patients with developmental dysplasia of the hip (DDH). We studied and compared the pelvic anatomy and morphology between the affected hemipelvis with the unaffected side in patients with unilateral Crowe type IV DDH using 3D imaging and analysis. Methods. A total of 20 patients with unilateral Crowe-IV DDH were included in the study. The contralateral side was considered normal in all patients. A coordinate system based on the sacral base (SB) in a reconstructed pelvic model was established. The pelvic orientations (tilt, rotation, and obliquity) of the affected side were assessed by establishing a virtual anterior pelvic plane (APP). The bilateral coordinates of the anterior superior iliac spine (ASIS) and the centres of hip rotation were established, and parameters concerning size and volume were compared for both sides of the pelvis. Results. The ASIS on the dislocated side was located inferiorly and anteriorly compared to the healthy side (coordinates on the y-axis and z-axis; p = 0.001; p = 0.031). The centre of hip rotation on the dislocated side was located inferiorly and medially compared to the healthy side (coordinates on the x-axis and the y-axis; p < 0.001; p = 0.003). The affected hemipelvis tilted anteriorly in the sagittal plane (mean 8.05° (SD 3.57°)), anteriorly rotated in the transverse plane (mean 3.31° (SD 1.41°)), and tilted obliquely and caudally in the coronal plane (mean 2.04° (SD 0.81°)) relative to the healthy hemipelvis. The affected hemipelvis was significantly smaller in the length, width, height, and volume than the healthy counterpart. (p = 0.014; p = 0.009; p = 0.035; p = 0.002). Conclusion. Asymmetric abnormalities were identified on the affected hemipelvis in patients with the unilateral Crowe-IV DDH using 3D imaging techniques. Improved understanding of the morphological changes may influence the positioning of the acetabular component at THA. Acetabular component malpositioning errors caused by anterior tilt of the affected hemi pelvis and the abnormal position of the affected side centre of rotation should be considered by orthopaedic surgeons when undertaking THA in patients with Crowe-IV DDH. Cite this article: Bone Joint J 2020;102-B(10):1311–1318

Aims. The aim of this study was to establish the incidence of developmental dysplasia of the hip (DDH) diagnosed after one-year of age in England, stratified by age, gender, year, and region of diagnosis. Patients and Methods. A descriptive observational study was performed by linking primary and secondary care information from two independent national databases of routinely collected data: the United Kingdom Clinical Practice Research Datalink and Hospital Episode Statistics. The study examined all children from 1 January 1990 to 1 January 2016 who had a new first diagnostic code for DDH aged between one and eight years old. Results. The incidence of late-diagnosed DDH was 1.28 per 1000 live births. Within the study population, 754 children were identified with a diagnosis of DDH after one-year of age. Of all late diagnoses, 536 (71.1%) were detected between one to two years of age. There were 608 female patients (80.6%) and 146 male patients (19.4%), giving a female-to-male ratio of 4.2:1. Distribution was evenly spread throughout England. Conclusion. The incidence of late-diagnosed DDH has not been reduced from that reported 35 years ago, prior to the introduction of the national selective screening programme for DDH. Cite this article: Bone Joint J 2019;101-B:281–287

Aims. The aim of this study was to examine whether hips with unilateral osteoarthritis (OA) secondary to developmental dysplasia of the hip (DDH) have significant asymmetry in femoral length, and to determine potential related factors. Patients and Methods. We enrolled 90 patients (82 female, eight male) with DDH showing unilateral OA changes, and 43 healthy volunteers (26 female, 17 male) as controls. The mean age was 61.8 years (39 to 93) for the DDH groups, and 71.2 years (57 to 84) for the control group. Using a CT-based coordinate measurement system, we evaluated the following vertical distances: top of the greater trochanter to the knee centre (femoral length GT), most medial prominence of the lesser trochanter to the knee centre (femoral length LT), and top of the greater trochanter to the medial prominence of the lesser trochanter (intertrochanteric distance), along with assessments of femoral neck anteversion and neck shaft angle. Results. The percentages of hips with an absolute difference of > 5 mm in femoral GT and LT lengths were significantly larger in the DDH group (24% for both) compared with those of the control group (2% and 7%, respectively). The femoral length GT of the affected femur was significantly shorter in Crowe I and longer in Crowe IV than that of the unaffected side. The affected-to-unaffected difference of the intertrochanteric distance showed positive correlation with that of the femoral length GT in Crowe I and Crowe II/III, and negative correlation with that of the femoral length LT in the Crowe I and Crowe IV groups. Conclusion. Hips with unilateral end-stage OA secondary to DDH show significant asymmetry in femoral length between both the greater and lesser trochanter and the knee compared with controls. The intertrochanteric distance was a morphological factor related to femoral-length asymmetry. When undertaking total hip arthroplasty (THA) in the presence of DDH, long leg radiographs or CT measurements should be used to assess true leg-length discrepancy. Cite this article: Bone Joint J 2019;101-B:297–302

Aims. The aim of this study was to compare outcomes of guided growth and varus osteotomy in treating Kalamchi type II avascular necrosis (AVN) after open reduction and Pemberton acetabuloplasty for developmental dysplasia of the hip (DDH). Methods. This retrospective study reviewed patients undergoing guided growth or varus osteotomy for Kalamchi type II AVN between September 2009 and January 2019. All children who had undergone open reduction and Pemberton acetabuloplasty for DDH with a minimum two-year follow-up were enrolled in the study. Demographic and radiological data, which included the head-shaft angle (HSA), neck-shaft angle (NSA), articulotrochanteric distance (ATD), Sharp angle (SA), and lateral centre-edge angle (LCEA) at baseline, two years, and at the extended follow-up, were compared. Revision rates were evaluated. Clinical outcomes using the Harris Hip Score were assessed two years postoperatively. Results. A total of 24 patients underwent guided growth and 19 underwent varus osteotomy, over a mean period of 3.3 years (95% confidence interval (CI) 2.8 to 3.8) and 5.2 years (95% CI 4.5 to 6.0), respectively. There were no differences in demographic and preoperative radiological data, except for a younger age at time of acetabuloplasty and larger ATD for the osteotomy group. The HSA did not differ at two years and the extended follow-up because of postoperative rebound in the osteotomy group. The NSA of the osteotomy group remained smaller postoperatively. There were no significant differences in the follow-up ATD, SA, and LCEA, except for a smaller two-year ATD of the osteotomy group. Seven patients (29.2%) in the guided growth group underwent revision surgery and none in the osteotomy group. The Harris Hip Score was similar between groups. Conclusion. Guided growth and varus osteotomy had comparable results in improving caput valgum deformity, given the rebound of lateral tilting of the physis after osteotomy correction. There were no differences in clinical outcomes at two years postoperatively. Cite this article: Bone Joint J 2022;104-B(7):902–908

Aims. The goal of closed reduction (CR) in the treatment of developmental dysplasia of the hip (DDH) is to achieve and maintain concentricity of the femoral head in the acetabulum. However, concentric reduction is not immediately attainable in all hips and it remains controversial to what degree a non-concentric reduction is acceptable. This prospective study is aimed at investigating the dynamic evolution of the hip joint space after CR in DDH using MRI. Methods. A consecutive series of patients with DDH who underwent CR since March 2014 were studied. Once the safety and stability were deemed adequate intraoperatively, reduction was accepted regardless of concentricity. Concentricity was defined when the superior joint space (SJS) and medial joint space (MJS) were both less than 2 mm, based on MRI. A total of 30 children, six boys and 24 girls, involving 35 hips, were recruited for the study. The mean age at CR was 13.7 months (3.5 to 27.6) and the mean follow-up was 49.5 months (approximately four years) (37 to 60). The joint space was evaluated along with the interval between the inverted and everted limbus. Results. Only three hips (8.6%) were fully concentric immediately after CR. During follow-up, 24 hips (68.6%) and 27 hips (77.1%) became concentric at six months and one year, respectively. Immediate SJS after CR decreased from 3.51 mm to 0.79 mm at six months follow-up (p = 0.001). SJS in the inverted group decreased from 3.75 mm to 0.97 mm at six months follow-up. SJS or MJS in the everted group were less than those in the inverted group at each time of follow-up (p = 0.008, p = 0.002). Conclusion. A stable, safe but non-concentric reduction achieved before the age of two years appears to improve over time with nearly 80% of hips becoming fully concentric by one year. Cite this article: Bone Joint J 2020;102-B(5):618–626

Twins are often considered to be at an increased risk of developmental dysplasia of the hip (DDH); we therefore investigated whether multiple births have a higher incidence of DDH, and if selective ultrasound scanning should be considered for these infants. We reviewed our records of all live births between 1 January 2004 and 31 December 2008 and included 25 246 single and 990 multiple births. Multiple births did not have a significantly higher incidence of DDH compared with single births (0.0030 vs 0.0023, p = 0.8939). Of the 990 multiple births, 267 had neonatal ultrasound scans and one case of DDH was diagnosed and treated successfully with a Pavlik harness. There were two late-presenting cases at eight and 14 months of age, neither of whom had risk factors for DDH and consequently had not had a neonatal scan. Whereas selective ultrasound scanning of multiple births would have led to earlier detection and treatment of the late-presenting cases, they did not have a significantly higher incidence of DDH compared with single births. We conclude that being a twin or triplet in itself is not a risk factor for DDH and that selective ultrasound scanning is not indicated for this population. Cite this article: Bone Joint J 2013;95-B:132–4

Aims. Rotational acetabular osteotomy (RAO) has been reported to be effective in improving symptoms and preventing osteoarthritis (OA) progression in patients with mild to severe develomental dysplasia of the hip (DDH). However, some patients develop secondary OA even when the preoperative joint space is normal; determining who will progress to OA is difficult. We evaluated whether the preoperative cartilage condition may predict OA progression following surgery using T2 mapping MRI. Methods. We reviewed 61 hips with early-stage OA in 61 patients who underwent RAO for DDH. They underwent preoperative and five-year postoperative radiological analysis of the hip. Those with a joint space narrowing of more than 1 mm were considered to have 'OA progression'. Preoperative assessment of articular cartilage was also performed using 3T MRI with the T2 mapping technique. The region of interest was defined as the weightbearing portion of the acetabulum and femoral head. Results. There were 16 patients with postoperative OA progression. The T2 values of the centre to the anterolateral region of the acetabulum and femoral head in the OA progression cases were significantly higher than those in patients without OA progression. The preoperative T2 values in those regions were positively correlated with the narrowed joint space width. The receiver operating characteristic analysis revealed that the T2 value of the central portion in the acetabulum provided excellent discrimination, with OA progression patients having an area under the curve of 0.858. Furthermore, logistic regression analysis showed T2 values of the centre to the acetabulum’s anterolateral portion as independent predictors of subsequent OA progression (p < 0.001). Conclusion. This was the first study to evaluate the relationship between intra-articular degeneration using T2 mapping MRI and postoperative OA progression. Our findings suggest that preoperative T2 values of the hip can be better prognostic factors for OA progression than radiological measures following RAO. Cite this article: Bone Joint J 2021;103-B(9):1472–1478

Aims. The purpose of this study was to analyze the incidence of the different ultrasound phenotypes of developmental dysplasia of the hip (DDH), and to determine their subsequent course. Patients and Methods. A consecutive series of 28 092 neonates was screened and classified according to the Graf method as part of a nationwide surveillance programme, and then followed prospectively. Abnormal hips were followed until they became normal (Graf type I). Type IIb hips and higher grades were treated by abduction in a Tübinger orthosis until normal. Dislocated hips underwent closed or open reduction. Results. Overall, 90.2% of hips were normal at birth. Type IIa hips (8.9%) became normal at a median of six weeks (interquartile range (IQR) 6 to 9). Type IIc and IId hips (0.67%) became normal after ten weeks (IQR 7 to 13). There were 19 type lll and eight type lV hips at baseline. There were 24 closed reductions and one open reduction. No late presentations of DDH were detected within the first five years of life. Conclusion. The incidence of DDH was eight per 1000 live births. The treatment rate was 1% (n = 273). The rate of first operations on the newborn hip was 0.86, and rate of open surgery was 0.04. The cumulative rate of open surgery was 0.07. The authors take the view that early identification and treatment in abduction of all dysplastic hips in early childhood reduces the rate of open reduction and secondary DDH-related surgery later in life. Cite this article: Bone Joint J 2018;100-B:1399–1404

Aims. There is no consensus about the best method of achieving equal leg lengths at total hip arthroplasty (THA) in patients with Crowe type-IV developmental dysplasia of the hip (DDH). We reviewed our experience of a consecutive series of patients who underwent THA for this indication. Patients and Methods. We retrospectively reviewed 78 patients (86 THAs) with Crowe type-IV DDH, including 64 women and 14 men, with a minimum follow-up of two years. The mean age at the time of surgery was 52.2 years (34 to 82). We subdivided Crowe type-IV DDH into two major types according to the number of dislocated hips, and further categorised them into three groups according to the occurrence of pelvic obliquity or spinal curvature. Leg length discrepancy (LLD) and functional scores were analysed. Results. Type-I included 53 patients with unilateral dislocation, in which 25 (category A) had no pelvic obliquity or spinal deformity, 19 (category B) had pelvic obliquity with a compensated spinal curvature and nine (category C) had pelvic obliquity and decompensated spinal degenerative changes. Type-II included 25 patients with one dislocated and one dysplastic hip, in which there were eight of category A, 15 of category B and two of category C. Pre-operatively, there were significant differences between the anatomical and functional LLD in type-IB (p = 0.005) and -IC (p < 0.001), but not in type-IA, -IIA or -IIB. Post-operatively, bony LLD increased significantly in types-IB, -IC and -IIB, whereas functional LLD decreased significantly in each type except for IIA. The mean functional LLD decreased from 30.7 mm (standard deviation (. sd. ) 18.5) pre-operatively to 6.2 mm (. sd. 4.4) post-operatively and the mean anatomical LLD improved from 35.8 mm (. sd. 19.7) pre-operatively to 12.4 mm (. sd. 8.3) post-operatively. Conclusion. Pelvic and spinal changes are common in patients with Crowe type-IV DDH and need to be taken into consideration when planning THA, in order to obtain equal leg lengths post-operatively. The principal subdivisions of Crowe type-IV DDH which we describe proved effective in achieving equal leg lengths and satisfactory outcomes. Cite this article: Bone Joint J 2017;99-B:872–9

To confirm whether developmental dysplasia of the hip has a risk of hip impingement, we analysed maximum ranges of movement to the point of bony impingement, and impingement location using three-dimensional (3D) surface models of the pelvis and femur in combination with 3D morphology of the hip joint using computer-assisted methods. Results of computed tomography were examined for 52 hip joints with DDH and 73 normal healthy hip joints. DDH shows larger maximum extension (p = 0.001) and internal rotation at 90° flexion (p < 0.001). Similar maximum flexion (p = 0.835) and external rotation (p = 0.713) were observed between groups, while high rates of extra-articular impingement were noticed in these directions in DDH (p < 0.001). Smaller cranial acetabular anteversion (p = 0.048), centre-edge angles (p < 0.001), a circumferentially shallower acetabulum, larger femoral neck anteversion (p < 0.001), and larger alpha angle were identified in DDH. Risk of anterior impingement in retroverted DDH hips is similar to that in retroverted normal hips in excessive adduction but minimal in less adduction. These findings might be borne in mind when considering the possibility of extra-articular posterior impingement in DDH being a source of pain, particularly for patients with a highly anteverted femoral neck. Cite this article: Bone Joint J 2014;96-B:580–9

Aims. The most important complication of treatment of developmental dysplasia of the hip (DDH) is avascular necrosis (AVN) of the femoral head, which can result in proximal femoral growth disturbances leading to pain, dysfunction, and eventually to early onset osteoarthritis. In this study, we aimed to identify morphological variants in hip joint development that are predictive of a poor outcome. Methods. We retrospectively reviewed all patients who developed AVN after DDH treatment, either by closed and/or open reduction, at a single institution between 1984 and 2007 with a minimal follow-up of eight years. Standard pelvis radiographs obtained at ages one, two, three, five, and eight years, and at latest follow-up were retrieved. The Bucholz-Ogden classification was used to determine the type of AVN on all radiographs. Poor outcome was defined by Severin classification grade 3 or above on the latest follow-up radiographs and/or the need for secondary surgery. With statistical shape modelling, we identified the different shape variants of the hip at each age. Logistic regression analysis was used to associate the different modes or shape variants with poor outcome. Results. In all, 135 patients with AVN were identified, with a minimum of eight years of follow-up. Mean age at time of surgery was 7.0 months (SD 0.45), and mean follow-up was 13.3 years (SD 3.7). Overall, 46% had AVN type 1 while 54% type 2 or higher. More than half of the patients (52.6%) had a poor outcome. We found 11 shape variants that were significantly associated with a poor outcome. These shape variants were predominantly linked to AVN type 2 or higher. Conclusion. Specific morphological characteristics on pelvis radiographs of AVN hips were predictive for poor outcome, at a very young age. There was an overall stronger association to Bucholz-Ogden types 2-3-4 with the exception of two modes at age two and five years, linked to AVN type 1. Cite this article: Bone Joint J 2021;103-B(5):999–1004

Developmental dysplasia of the hip (DDH) should be diagnosed as early as possible to optimise treatment. The current United Kingdom recommendations for the selective screening of DDH include a clinical examination at birth and at six weeks. In Northern Ireland babies continue to have an assessment by a health visitor at four months of age. As we continue to see late presentations of DDH, beyond one year of age, we hypothesised that a proportion had missed an opportunity for earlier diagnosis. We expect those who presented to our service with Tonnis grade III or IV hips and decreased abduction would have had clinical signs at their earlier assessments. We performed a retrospective review of all patients born in Northern Ireland between 2008 and 2010 who were diagnosed with DDH after their first birthday. There were 75 856 live births during the study period of whom 645 children were treated for DDH (8.5 per 1000). The minimum follow-up of our cohort from birth, to detect late presentation, was four years and six months. Of these, 32 children (33 hips) were diagnosed after their first birthday (0.42 per 1000). With optimum application of our selective screening programme 21 (65.6%) of these children had the potential for an earlier diagnosis, which would have reduced the incidence of late diagnosis to 0.14 per 1000. As we saw a peak in diagnosis between three and five months our findings support the continuation of the four month health visitor check. Our study adds further information to the debate regarding selective versus universal screening. . Cite this article: Bone Joint J 2015;97-B:1572–6

Aims. The aim of this study was to evaluate the correlation between Salter’s criteria and Kalamchi’s classification of avascular necrosis in patients treated for developmental dysphasia of the hip (DDH). Patients and Methods. The study involved a retrospective analysis of 123 patients (123 hips) with DDH treated by operative and non-operative reduction before the age of two years, with a minimum follow-up of ten years. Salter’s criteria (S1 to S4) were determined from radiographs obtained at one to two years post-reduction, whilst the Kalamchi grade was determined from radiographs obtained at ten or more years of age. Early post-reduction radiographs were also used to evaluate the centre-head distance discrepancy (CHDD) and the occurrence of a dome-shaped deformity of the proximal femoral metaphysis (D-shaped metaphysis). The prognosis was described as good (Kalamchi grade K0 or KI), fair (Kalamchi grade KII) or poor (Kalamchi grade KIII or KIV) for analysis and correlation with the early Salter criteria, CHDD and D-shaped metaphysis. Results. S1 and S2 criteria were predictive of a poor prognosis. The outcome following S3, S4 and S3 + S4 varied; 18 (40%) had a good prognosis, 17 (38%) a fair prognosis and ten (22%) a poor prognosis. A CHDD ≥ 10% and a D-shaped metaphysis were also predictive of a poor prognosis. Conclusion. The Salter criteria were predictive of the Kalamchi grade of avascular necrosis in patients with DDH aged ten or more years after reduction of the hip. . Cite this article: Bone Joint J 2017;99-B:1115–20

Aims. A clicky hip is a common referral for clinical and sonographic screening for developmental dysplasia of the hip (DDH). There is controversy regarding whether it represents a true risk factor for pathological DDH. Therefore a 20-year prospective, longitudinal, observational study was undertaken to assess the relationship between the presence of a neonatal clicky hip and pathological DDH. Patients and Methods. A total of 362 infants from 1997 to 2016 were referred with clicky hips to our ‘one-stop’ paediatric hip screening clinic. Hips were assessed clinically for instability and by ultrasound imaging using a simplified Graf/Harcke classification. Dislocated or dislocatable hips were classified as Graf Type IV hips. Results. The mean age at presentation was 13.8 weeks (12.8 to 14.7). In all 351 out of 362 children (97.0%) had Graf Type I hips (normal) that required no treatment. Nine children (2.5%) had Graf Type II hips but all resolved to Graf Type I hips on follow-up scans. One child (0.3%) had Graf Type III hip dysplasia and one child (0.3%) had an irreducible hip dislocation. The two pathological hips were associated with unilateral limited hip abduction. Mean referrals increased from 12.9 to 23.3 each year (p = 0.002) from the first decade of the study to the second, driven by increasing primary care referrals (5.5 versus 16.7 per year, p < 0.001). Conclusion. Most clicky hips required no treatment other than reassurance to parents. Clicky hips with a normal hip examination should be considered a variant of normal childhood and not a risk factor for DDH. However, an abnormal hip examination including unilateral limited hip abduction should prompt urgent further investigations. Cite this article: Bone Joint J 2017;99-B:1533–6

Aims. This study aimed to explore whether intraoperative nerve monitoring can identify risk factors and reduce the incidence of nerve injury in patients with high-riding developmental dysplasia. Patients and Methods. We conducted a historical controlled study of patients with unilateral Crowe IV developmental dysplasia of the hip (DDH). Between October 2016 and October 2017, intraoperative nerve monitoring of the femoral and sciatic nerves was applied in total hip arthroplasty (THA). A neuromonitoring technician was employed to monitor nerve function and inform the surgeon of ongoing changes in a timely manner. Patients who did not have intraoperative nerve monitoring between September 2015 and October 2016 were selected as the control group. All the surgeries were performed by one surgeon. Demographics and clinical data were analyzed. A total of 35 patients in the monitoring group (ten male, 25 female; mean age 37.1 years (20 to 46)) and 56 patients in the control group (13 male, 43 female; mean age 37.9 years (23 to 52)) were enrolled. The mean follow-up of all patients was 13.1 months (10 to 15). Results. The two groups had no significant differences in preoperative data. In the monitoring group, ten nerve alerts occurred intraoperatively, and no neural complications were detected postoperatively. In the control group, six patients had neural complications. The rate of nerve injury was lower in the monitoring group than in the control group, but this did not achieve statistical significance. The degree of leg lengthening was significantly greater in the monitoring group than in the control group. In further analyses, patients who had previous hip surgery were more likely to have intraoperative nerve alerts and postoperative nerve injury. Conclusion. Nerve injury usually occurred during the processes of exposure and reduction. The use of intraoperative nerve monitoring showed a trend towards reduced nerve injury in THA for Crowe IV DDH patients. Hence, we recommend its routine use in patients undergoing leg lengthening, especially in those with previous hip surgery. Cite this article: Bone Joint J 2019;101-B:1438–1446

The aim of this prospective study was to investigate prematurity as a risk factor for developmental dysplasia of the hip (DDH). The hips of 221 infants (88 female, 133 male, mean age 31.11 weeks; standard deviation (. sd. ) 2.51) who were born in the 34th week of gestation or earlier, and those of 246 infants (118 female, 128 male, mean age 40.22 weeks; . sd. 0.36) who were born in the 40th week of gestation, none of whom had risk factors for DDH, were compared using physical examination and ultrasound according to the technique of Graf, within one week, after the correction of gestational age to the 40th week after birth or one week since birth, respectively. Both hips of all infants were included in the study. Ortolani’s and Barlow’s tests and restricted abduction were accepted as positive findings on examination. There was a statistically significant difference between pre- and full-term infants, according to the incidence of mature and immature hips (p < 0.001). The difference in the proportion of infants with an α angle < 60° between the two groups was statistically significant (p < 0.001). The incidence of pathological dysplasia (α angle < 50 º) was not significantly different in the two groups (p = 1.000). The Barlow sign was present in two (0.5%) pre-term infants and in 14 (2.8%) full-term infants. . These results suggests that prematurity is not a predisposing factor for DDH. Cite this article: Bone Joint J 2015; 97-B:716–20

Aims. Psychological factors play a critical role in patient presentation, satisfaction, and outcomes. Pain catastrophizing, anxiety, and depression are important to consider, as they are associated with poorer outcomes and are potentially modifiable. The aim of this study was to assess the level of pain catastrophizing, anxiety, and depression in patients with a range of hip pathology and to evaluate their relationship with patient-reported psychosocial and functional outcome measures. Patients and Methods. Patients presenting to a tertiary-centre specialist hip clinic were prospectively evaluated for outcomes of pain catastrophizing, anxiety, and depression. Validated assessments were undertaken such as: the Pain Catastrophizing Scale (PCS), the Hospital Anxiety Depression Scale (HADS), and the 12-Item Short-Form Health Survey (SF-12). Patient characteristics and demographics were also recorded. Multiple linear regression modelling, with adaptive least absolute shrinkage and selection operator (LASSO) variable selection, was used for analysis. Results. A total of 328 patients were identified for inclusion, with diagnoses of hip dysplasia (DDH; n = 50), femoroacetabular impingement (FAI; n = 55), lateral trochanteric pain syndrome (LTP; n = 23), hip osteoarthrosis (OA; n = 184), and avascular necrosis of the hip (AVN; n = 16) with a mean age of 31.0 years (14 to 65), 38.5 years (18 to 64), 63.7 years (20 to 78), 63.5 years (18 to 91), and 39.4 years (18 to 71), respectively. The percentage of patients with abnormal levels of pain catastrophizing, anxiety, or depression was: 22.0%, 16.0%, and 12.0% for DDH, respectively; 9.1%, 10.9%, and 7.3% for FAI, respectively; 13.0%, 4.3%, and 4.3% for LTP, respectively; 21.7%, 11.4%, and 14.1% for OA, respectively; and 25.0%, 43.8%, and 6.3% for AVN, respectively. HADS Anxiety (HADSA) and Hip Disability Osteoarthritis Outcome Score Activities of Daily Living subscale (HOOS ADL) predicted the PCS total (adjusted R. 2. = 0.4599). Age, HADS Depression (HADSD), and PCS total predicted HADSA (adjusted R. 2. = 0.4985). Age, HADSA, patient’s percentage of perceived function, PCS total, and HOOS Quality of Life subscale (HOOS QOL) predicted HADSD (adjusted R. 2. = 0.5802). Conclusion. Patients with hip pathology may exhibit significant pain catastrophizing, anxiety, and depression. Identifying these factors and understanding the impact of psychosocial function could help improve patient treatment outcomes. Perioperative multidisciplinary assessment may be a beneficial part of comprehensive orthopaedic hip care. Cite this article: Bone Joint J 2019;101-B:800–807

Aims. The aim of this prospective cohort study was to evaluate the effectiveness of the neonatal hip instability screening programme. Patients and Methods. The study involved a four-year observational assessment of a neonatal hip screening programme. All newborns were examined using the Barlow or Ortolani manoeuvre within 72 hours of birth; those with positive findings were referred to a ‘one-stop’ screening clinic for clinical and sonographic assessment of the hip. The results were compared with previous published studies from this unit. Results. A total of 124 newborns with a positive Barlow or Ortolani manoeuvre, clunk positive, or ‘unstable’ were referred. Five were found to have clinical instability of the hip. Sonographically, 92 newborns had Graf Type I hips, 12 had Graf Type II hips, and 20 had Graf Type IV hips. The positive predictive value (PPV) of clinical screening was 4.0% and the PPV of sonography was 16.1%. This has led to an increased rate of surgery for DDH. Conclusion. Compared with previously published ten-year and 15-year studies, there has been a marked deterioration in the PPV in those referred with potential instability of the hip. There appears to be a paradox, with rising referrals and a decreasing PPV combined with an increasing rate of surgery in newborns with developmental dysplasia of the hip. Cite this article: Bone Joint J 2018;100-B:806–10

The treatment of substantial proximal femoral bone loss in young patients with developmental dysplasia of the hip (DDH) is challenging. We retrospectively analysed the outcome of 28 patients (30 hips) with DDH who underwent revision total hip replacement (THR) in the presence of a deficient proximal femur, which was reconstructed with an allograft prosthetic composite. The mean follow-up was 15 years (8.5 to 25.5). The mean number of previous THRs was three (1 to 8). The mean age at primary THR and at the index reconstruction was 41 years (18 to 61) and 58.1 years (32 to 72), respectively. The indication for revision included mechanical loosening in 24 hips, infection in three and peri-prosthetic fracture in three. Six patients required removal and replacement of the allograft prosthetic composite, five for mechanical loosening and one for infection. The survivorship at ten, 15 and 20 years was 93% (95% confidence interval (CI) 91 to 100), 75.5% (95% CI 60 to 95) and 75.5% (95% CI 60 to 95), respectively, with 25, eight, and four patients at risk, respectively. Additionally, two junctional nonunions between the allograft and host femur required bone grafting and plating. An allograft prosthetic composite affords a good long-term outcome in the management of proximal femoral bone loss in revision THR in patients with DDH, while preserving distal host bone

Aims. Despite the presence of screening programmes, infants continue to present with late developmental dysplasia of the hip (DDH), the impact of which is significant. The aim of this study was to assess infants with late presenting dislocation of the hip despite universal clinical neonatal and selective ultrasound screening. Patients and Methods. Between 01 January 1997 to 31 December 2011, a prospective, longitudinal study was undertaken of a cohort of 64 670 live births. Late presenting dislocation was defined as presentation after three months of age. Diagnosis was confirmed by ultrasound and plain radiography. Patient demographics, referral type, reason for referral, risk factors (breech presentation/strong family history) and clinical and radiological findings were recorded. Results. There were 31 infants with an irreducible dislocation of the hip, an incidence of 0.48 (95% confidence interval (CI) 0.34 to 0.68) per 1000 live births. Of these, 18 (0.28 (95% CI 0.17 to 0.44) per 1000 live births; 58%) presented late. All infants had a documented normal newborn clinical examination and no abnormality reported in the six to eight week check. Of the 18 late presenting cases 72% (n = 13) had no risk factors: 16 were referred by GPs and two were late due to administrative issues (missed appointments). The mean time to diagnosis was 62.4 weeks (19 to 84). Conclusion. Despite universal clinical neonatal and selective ultrasound screening, late cases of irreducible hip dislocation still occur. We recommend an update of the national screening programme for DDH, a review of training and education of healthcare professionals involved in the physical examination of neonates and infants, and the addition of a further assessment after the six to eight week check. Cite this article: Bone Joint J 2017;99-B:1250–5

Aims. This pilot study aimed to evaluate prospectively the use of inlet radiographs of the hip as an alternative method of the assessment of reduction after the surgical treatment of developmental dysplasia of the hip (DDH). Patients and Methods. The children in this study underwent surgery between January 2013 and January 2015. All had inlet radiographs and CT scans post-operatively. Data were analysed by determining inter-observer reliability and intra-observer reproducibility, using the kappa value (K). Differences were settled by discussion between the two observers until a consensus was reached. The sensitivity and specificity of the radiographic and CT results were compared. A total of 26 radiographs were obtained from 23 children, with a mean age of 2.38 years (one to five). Results. Similar high levels of intra- and inter-observer agreement were observed (K = 0.834, 95% confidence interval (CI)). There was a high agreement between the radiographic and CT results (K = 0.834, 5% CI), with excellent sensitivity and a specificity of 95.5%. Conclusion. These results suggest that inlet radiographs may be a reliable method of assessing the reduction of the hip after the surgical treatment of DDH. Cite this article: Bone Joint J 2017;99-B:697–701

Aims. Open reduction is required following failed conservative treatment of developmental dysplasia of the hip (DDH). The Ludloff medial approach is commonly used, but poor results have been reported, with rates of the development of avascular necrosis (AVN) varying between 8% and 54%. This retrospective cohort study evaluates the long-term radiographic and clinical outcome of dislocated hips treated using this approach. Patients and Methods. Children with a dislocated hip, younger than one year of age at the time of surgery, who were treated using a medial approach were eligible for the study. Radiographs were evaluated for the degree of dislocation and the presence of an ossific nucleus preoperatively, and for the degree of AVN and residual dysplasia at one and five years and at a mean of 12.7 years (4.6 to 20.8) postoperatively. Radiographic outcome was assessed using the Severin classification, after five years of age. Further surgical procedures were recorded. Functional outcome was assessed using the Pediatric Outcomes Data Collection Instrument (PODCI) or the Hip Disability and Osteoarthritis Outcome Score (HOOS), depending on the patient’s age. Results. A total of 52 children (58 hips) were included. At the latest follow-up, 11 hips (19%) showed signs of AVN. Further surgery was undertaken in 13 hips (22%). A total of 13 hips had a poor radiological outcome with Severin type III or higher. Of these, the age at the time of surgery was significantly higher (p < 0.05) than in those with a good Severin type (I or II). The patient-reported outcomes were significantly worse (p < 0.05) in children with a poor Severin classification. Conclusion. This retrospective long-term follow-up study shows that one in five children with DDH who undergo open reduction using a medial surgical approach has poor clinical and/or radiological outcome. The poor outcome is not related to the presence of AVN (19%), but due to residual dysplasia. Cite this article: Bone Joint J 2018;100-B:822–7

In 2017, the British Society for Children’s Orthopaedic Surgery engaged the profession and all relevant stakeholders in two formal research prioritization processes. In this editorial, we describe the impact of this prioritization on funding, and how research in children’s orthopaedics, which was until very recently a largely unfunded and under-investigated area, is now flourishing. Establishing research priorities was a crucial step in this process.

Cite this article: Bone Joint J 2024;106-B(5):422–424.

Aims

The aim of this study was to investigate whether anterior pelvic plane-pelvic tilt (APP-PT) is associated with distinct hip pathomorphologies. We asked: is there a difference in APP-PT between young symptomatic patients being evaluated for joint preservation surgery and an asymptomatic control group? Does APP-PT vary among distinct acetabular and femoral pathomorphologies? And does APP-PT differ in symptomatic hips based on demographic factors?

The purpose of this study was to determine patient-reported outcomes of patients with mild to moderate developmental dysplasia of the hip (DDH) and femoroacetabular impingement (FAI) undergoing arthroscopy of the hip in the treatment of chondrolabral pathology. A total of 28 patients with a centre-edge angle between 15° and 19° were identified from an institutional database. Their mean age was 34 years (18 to 53), with 12 female and 16 male patients. All underwent labral treatment and concomitant correction of FAI. There were nine reoperations, with two patients requiring revision arthroscopy, two requiring periacetabular osteotomy and five needing total hip arthroplasty. Patients who required further major surgery were more likely to be older, male, and to have more severe DDH with a larger alpha angle and decreased joint space. . At a mean follow-up of 42 months (24 to 89), the mean modified Harris hip score improved from 59 (20 to 98) to 82 (45 to 100; p < 0.001). The mean Western Ontario and McMaster Universities Osteoarthritis Index score improved from 30 (1 to 61) to 16 (0 to 43; p < 0.001). Median patient satisfaction was 9.0/10 (1 to 10). Patients reported excellent improvement in function following arthroscopy of the hip. This study shows that with proper patient selection, arthroscopy of the hip can be successful in the young patient with mild to moderate DDH and FAI. . Cite this article: Bone Joint J 2015;97-B:1316–21