Functional outcomes in children with osteonecrosis secondary to treatment of developmental dysplasia of the hip

Assessing Avascular Necrosis Risk and Outcomes After Open Reduction for Developmental Dysplasia of the Hip in Children

Background Avascular necrosis (AVN) of the femoral head is a serious complication after surgical treatment of developmental dysplasia of the hip (DDH). The main objective of this study is to identify the incidence of AVN and to define AVN risk factors. The study also aims to identify the effects of AVN and other factors on final clinical and radiological outcomes. Methods All patients in the study were managed according to King Saud University protocol for surgical treatment of DDH. Occurrence of AVN was reported. All affected hips were evaluated clinically and radiologically after six and 12 months and at final follow-up. Significant variables from the univariate analysis were entered into multivariate regression models. Results A total of 131 patients were included in the study involving 189 hips with DDH. AVN was diagnosed postoperatively in 23 (12%) hips. In the multivariate regression analysis, the presence of AVN (p=0.002), prolonged casting (p=0.016) and the need for a second surgery (p=0.029) were strong determinants of unsatisfactory clinical outcomes. Worse radiological outcomes were significantly associated with the presence of AVN (p=0.002), previous trials of closed reduction (p=0.032) and the need for a second surgery (p=0.013). In the last multivariate regression model, a previous trial of closed reduction (p=0.001), absence of an ossified femoral head (OFH) (p=< 0.001), prolonged casting (p=0.038), and the need for second surgery (p=0) were strong risk factors for AVN. Conclusions The current study highlighted the factors responsible for AVN occurrence after open DDH reduction. The factors which are strong determinants of unsatisfactory clinical and radiological outcomes were identified. Overcoming these factors is mandatory to improve the results.

Impact of avascular necrosis on outcomes in the management of developmental dysplasia of hip: a systematic review

Avascular necrosis (AVN) is a known complication during the management of developmental dysplasia of the hip (DDH). It has the potential to alter the growth of the head or acetabulum and prevent the best outcomes. While past literature has evaluated the risks of AVN and strategies to avoid it, studies on the impact of AVN on the outcomes are scarce. In this systematic review, we aim to study the extent of the effects of AVN on the outcomes, in the management of DDH. In this systematic review series for 1990 to 2021 were pooled. The clinical and radiological outcomes of the AVN and non-AVN groups were compared. The effects of other modifying factors were also evaluated. A total of 170 AVN and 585 non-AVN hips from 21 papers were compared. The analysis did not show any statistically significant difference between the AVN and non-AVN groups in terms of clinical or radiological parameters. Interestingly patients who had the index surgery at a younger age had a higher risk of further surgery, with acetabular osteotomy being the most common secondary procedure. The negative impact of AVN may not be as severe as previously thought. Thus, the fear of AVN should not take precedence over the primary goal of DDH management i.e. obtaining a stable concentric mobile hip.

An in-depth analysis of young adults with osteonecrosis secondary to developmental dysplasia of the hip who underwent total hip arthroplasty

BACKGROUND

Patients with osteonecrosis of the femoral head secondary to DDH frequently require total hip arthroplasty (THA), but it is not well understood which factors necessitate this requirement. We determined the incidence of THA in patients who have osteonecrosis secondary to DDH and factors associated with need for THA.

METHODS

We included patients who received closed or open reductions between 1995 and 2005 with subsequent development of osteonecrosis. We determined osteonecrosis according to Bucholz and Ogden; osteoarthritis severity (Kellgren-Lawrence), subluxation (Shenton's line); neck-shaft angle; and acetabular dysplasia (centre-edge and Sharp angles). We also recorded the number of operations of the hip in childhood and reviewed case notes of patients who received THA to describe clinical findings prior to THA. We assessed the association between radiographic variables and the need for THA using univariate logistic regression.

RESULTS

Of 140 patients (169 hips), 22 patients received 24 THA (14%) at a mean age of 21.3 ± 3.7 years. Associated with the need for THA were grade III osteonecrosis (OR 4.25; 95% CI 1.70-10.77; p = 0.0019), grade IV osteoarthritis (21.8; 7.55-68.11; p < 0.0001) and subluxation (8.22; 2.91-29.53; p = 0.0003). All patients who required THA reported at least 2 of: severe pain including at night, stiffness, and reduced mobility. Acetabular dysplasia and number of previous operations were not associated with the need for THA.

CONCLUSIONS

We identified a 14% incidence of THA by age 34 years in patients with osteonecrosis secondary to DDH. Grade III osteonecrosis (global involvement femoral head and neck) was strongly associated with THA, emphasising the importance to avoid osteonecrosis when treating DDH.

A Comparison Between 3 Functional Hip Scores for Evaluation of the Pediatric Hip

BACKGROUND

This investigation aimed to determine the degree of correlation among 3 functional scales for evaluating the hip in pediatric patients and determine the correlation between measures of global function and outcome.

METHODS

We performed a prospective study of 173 consecutive patients (M age = 13 ± 3 y) being followed for developmental dysplasia of the hip (n = 122, 71%), slipped capital femoral epiphysis (n = 31, 18%), or Legg-Calve-Perthes disease (n = 20, 12%). We evaluated patients clinically, and we compiled scores for the Iowa Hip Score (IHS), Harris Hip Score (HHS), and Children's Hospital Oakland Hip Evaluation Scale (CHOHES). Patients concomitantly completed the Pediatric Outcomes Data Collection Instrument (PODCI) at the same clinic visit. We assessed Global Functioning Scale the and the Sports and Physical Functioning Core Scale of the PODCI. We determined the degree of correlation between the functional hip scales and between each scale and the PODCI scales using Spearman rank correlation coefficients.

RESULTS

The correlations between the IHS, HHS, and CHOHES scores were robust (IHS and HHS ρ = 0.991; IHS and CHOHES ρ = 0.933; HHS and CHOHES ρ = 0.938; all P < 0.001). The correlation between the Global Functioning Scale of the PODCI and the 3 hip scores was ρ = 0.343 for the IHS, ρ = 0.341 for the HHS, and ρ = 0.352 for the CHOHES (all P < 0.001). The correlation between the sports and physical functioning core scale of the PODCI and the 3 hip scores was ρ = 0.324 for the IHS, ρ = 0.329 for the HHS, and ρ = 0.346 for the CHOHES (all P < 0.001).

CONCLUSIONS

In a pediatric population with diverse hip pathology, there was a very strong correlation between scores on the IHS, HHS, and CHOHES. However, none of these 3 most commonly used hip scores correlated strongly with the global functioning scale or sports and physical functioning core scale of the PODCI. The most frequently used scores to determine the outcome of pediatric patients with hip pathology correlate strongly with each other but do not necessarily relate to global functional results.

LEVEL OF EVIDENCE

Level IV.

Postsurgical Analysis of Gait, Radiological, and Functional Outcomes in Children with Developmental Dysplasia of the Hip

BACKGROUND

Children undergoing DDH correction surgery may experience gait abnormalities following soft tissue releases and bony procedures. The purpose of this study was to compare the residual gait changes, radiological outcomes, and functional outcomes in children who underwent DDH surgery with those in healthy controls.

METHODS

Inertial motion sensors were used to record the gait of 14 children with DDH and 14 healthy children. Pelvic X-ray was performed to determine the Severin classification and the presence of femoral head osteonecrosis (Bucholz-Odgen classification). For functional evaluation, the Children's Hospital Oakland Hip Evaluation Scale (CHOHES) was used.

RESULTS

There was no difference in spatial parameters between the two groups. In terms of temporal parameters, the DDH-affected limbs had a shorter stance phase (p < 0.001) and a longer swing phase (p < 0.001) than the control group. The kinematic study showed that the affected limb group had smaller hip adduction angle (p = 0.002) and increased internal rotation (p = 0.006) with reduced upward pelvic tilt (p = 0.020). Osteonecrosis was graded II, III, and IV in five, three, and one patients, respectively. Five patients had no AVN changes. The Severin classification was grade I, II, and III for six, three, and five patients, respectively. Most patients had good functional outcomes on the CHOHES, with a mean total score of 96.64 ± 5.719. Multivariate regression analysis revealed that weight, height, and femoral osteotomy were independent predictors for gait, radiological and functional outcome.

CONCLUSION

Despite good functional scores overall, some children had poor radiological outcomes and gait abnormalities. Our results identified the risk factors for poor outcomes, and we recommend specified rehabilitative strategies for long-term management.

Guided growth versus varus osteotomy for type II avascular necrosis following surgery for developmental dysplasia of the hip

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.

Femoral osteotomy is not recommended for children aged 2-3 years with Tönnis grade III developmental dysplasia of the hip

The objective of this study was to compare outcomes following open reduction with and without femoral shortening when treating patients aged 2-3 years with Tönnis grade III developmental dysplasia of the hip (DDH). In this prospective study, 78 patients (6 boys and 72 girls; mean age: 27.8 months; age range: 24-35 months) with Tönnis grade III DDH at our hospital from January 2014 to August 2017 were included. There were 34 hips in the without femoral shortening group and 44 hips in the femoral shortening group. Clinical outcomes were rated using the modified McKay criteria, and the hips were graded using the Severin score. Avascular necrosis (AVN) and redislocation were assessed. Mean follow-up was 26.5 months (range 17-32 months). In the without femoral shortening group (n = 34), there were five patients with AVN (14.7%), and 30 scored excellent and 4 scored good results per the modified McKay criteria. Further, 28 excellent and six good results were obtained using the Severin scale; no patient had redislocation. In the femoral shortening group(n = 44), there were seven patients with AVN (15.9%), and 38 scored excellent and six scored good results per the modified McKay criteria. Further, 31 excellent and 13 good results were obtained using the Severin scale; no patient had redislocation. Additionally, there were no statistically significant differences based on Modified McKay criteria, Severin score and AVN rate. Femoral shortening is not required for children aged 2-3 years with Tönnis grade III DDH.

Evaluation of avascular necrosis risk factors after closed reduction for developmental dysplasia of the hip before walking age

Avascular necrosis (AVN) of the femoral head is one of the most important complications after closed reduction and spica cast application in developmental dysplasia of the hip (DDH) treatment. This study aims to put forth the impact of closed reduction age and other factors which can cause AVN. Inclusion criteria of the study were: closed reduction and spica cast application before walking age (12 months) and minimum 2 years duration of follow-up. The presence of femoral head ossific nucleus, International Hip Dysplasia Institute (IHDI) score, acetabular indices and AVN were evaluated from radiographies. Hip abduction angles were evaluated on CT images. The absence of the ossific nucleus at the closed reduction time and preoperative IHDI grade were not significant risk factors for AVN (respectively OR = 2.83; 95% CI, 0.99-8.07; P = 0.052; OR = 2.5; 95% CI, 0.85-7.32; P = 0.094). For the patients older than 10 months, (1) the absence of the ossific nucleus was a significant risk factor for grade 2 or higher AVN according to the Bucholz Ogden criteria (P = 0.020) and (2) the higher preoperative IHDI grade (IHDI 3-4) was a significant risk factor for AVN (P = 0.032). AVN of the femoral head was a significant risk factor for fair or poor clinical outcome (P = 0.001). It is not reasonable to wait for radiological visibility of the ossific nucleus to prevent femoral head AVN before applying closed reduction and spica cast, irrespective of the age interval.

Morphological variants to predict outcome of avascular necrosis in developmental dysplasia of the hip

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.

A Review of the Psychometric Performance of Selected Child and Adolescent Preference-Based Measures Used to Produce Utilities for Child and Adolescent Health

OBJECTIVE

This review examined the psychometric performance of 4 generic child- and adolescent-specific preference-based measures that can be used to produce utilities for child and adolescent health.

METHODS

A systematic search was undertaken to identify studies reporting the psychometric performance of the Child Health Utility (CHU9D), EQ-5D-Y (3L or 5L), and Health Utilities Index Mark 2 (HUI2) or Mark 3 (HUI3) in children and/or adolescents. Data were extracted to assess known-group validity, convergent validity, responsiveness, reliability, acceptability, and feasibility. Data were extracted separately for the dimensions and utility index where this was reported.

RESULTS

The review included 76 studies (CHU9D n = 12, EQ-5D-Y-3L n = 20, HUI2 n = 26,HUI3 n = 43), which varied considerably across conditions and sample size. EQ-5D-Y-3L had the largest amount of evidence of good psychometric performance in proportion to the number of studies examining performance. The majority of the evidence related to EQ-5D-Y-3L was based on dimensions. CHU9D was assessed in fewer studies, but the majority of studies found evidence of good psychometric performance. Evidence for HUI2 and HUI3 was more mixed, but the studies were more limited in sample size and statistical power, which was likely to have affected performance.

CONCLUSIONS

The heterogeneity of published studies means that the evidence is based on studies across a range of countries, populations and conditions, using different study designs, different languages, different value sets and different statistical techniques. Evidence for CHU9D in particular is based on a limited number of studies. The findings raise concerns about the comparability of self-report and proxy-report responses to generate utility values for children and adolescents.

Patient-reported outcomes in young adults with osteonecrosis secondary to developmental dysplasia of the hip - a longitudinal and cross-sectional evaluation

Background

Osteonecrosis of the femoral head is a common complication in the treatment of developmental dysplasia of the hip (DDH). While functional outcomes of affected patients are good in childhood, it is not clear how they change during the transition to young adulthood. This study determined the relationship between osteonecrosis and hip function, physical function and health status in adolescents and young adults.

Methods

We performed a cross-sectional study of 169 patients with a mean age of 19.7 ± 3.8 years with and without osteonecrosis following an open or closed reduction (1995–2005). We also performed a separate longitudinal evaluation of an historical cohort of 54 patients with osteonecrosis, embedded in this sample. All completed patient-reported outcome measures in 2015/2016 to quantify hip function (maximum score 100); physical function (maximum score 100); and general health status (maximum score 1). We graded all radiographs for subtype of osteonecrosis (Bucholz-Ogden); acetabular dysplasia (centre-edge angle); subluxation (Shenton’s line); and osteoarthritis (Kellgren-Lawrence). Analyses were adjusted for the number of previous surgical procedures on the hip and for the severity of residual hip dysplasia.

Results

In 149 patients (186 hips) with and without osteonecrosis, the mean differences (95% confidence interval) in hip function, physical function and quality of life were − 4.7 (− 10.26, 0.81), − 1.03 (− 9.29, 7.23) and 0.10 (− 1.15, 1.18), respectively. Adjusted analyses stratified across types of osteonecrosis showed that only patients with Bucholz-Odgen grade III had reduced hip function (p < 0.01) and physical function (p < 0.05) but no difference in health-related quality of life when compared to no osteonecrosis.

Conclusion

Osteonecrosis secondary to DDH is a relatively benign disorder in adolescents and young adulthood. Affected patients demonstrated minimal physical disability, a normal quality of life but reduced hip function.

Efficacy of closed reduction for developmental dysplasia of the hip: midterm outcomes and risk factors associated with treatment failure and avascular necrosis

BACKGROUND

The purpose of this study was to evaluate the efficacy of closed reduction (CR) in the treatment of developmental dysplasia of the hip (DDH) and to investigate risk factors associated with CR failure and avascular necrosis (AVN) occurrence in follow-ups.

METHODS

The study retrospectively included 110 patients and 138 hips with DDH diagnosis that underwent closed reduction between February 2012 and November 2015 in our single tertiary medical institution. The failure rate of CR and the underlying risk factors were evaluated. Meanwhile, the incidence of AVN and the related risk factors among the successful CR cases were assessed.

RESULTS

The overall failure rate of DDH treated by CR in the present study was 31.16% (43/138). Risk factors for the CR failure were older age at the time of CR (≥ 18.35 month), large medical interval before CR (≥ 35.35 mm), and severer dislocation of the affected hip (IDHI grades III and IV). The incidence of AVN was 8.33% (6/72) in patients with successful CR at the last follow-up. No significant risk factors had been established in the present study that associated with the AVN occurrence.

CONCLUSIONS

For the treatment of DDH with CR, patients with younger age might achieve better outcomes; early diagnosis and early treatment might be the key point in the DDH treatment.

Risk factors associated with unsatisfactory hip function in children with late-diagnosed developmental dislocation of the hip treated by open reduction

BACKGROUND

Open reduction with or without pelvic and femoral osteotomy is the accepted treatment option for children older than 18 months with developmental dislocation of the hip (DDH). However, few studies have investigated hip function in children with late DDH treated by open reduction. Therefore, we performed a retrospective study investigating the risk factors potentially associated with unsatisfactory hip function.

HYPOTHESIS

We hypothesized that some risk factors can be associated with unsatisfactory hip function in patients with late DDH treated by open reduction.

PATIENTS AND METHODS

We retrospectively reviewed the clinical and radiographic data of 79 children (98 hips, mean age 39.7±18.6 months; range, 19-95.3) with late-detected DDH treated by open reduction. Acetabular index (AI), Tönnis grade, Center Edge Angle (CEA), avascular necrosis of the femoral epiphysis (AVN), and Severin radiographic grade were evaluated on radiographs. Hip function was rated according to modified Outcome Evaluation Standard for Congenital Dislocation of the Hip with a maximum score of 15. According to type of surgery, patients were divided into four groups: open reduction alone (Group A), open reduction in conjunction with pelvic osteotomy (Group B), and open reduction in conjunction with femoral osteotomy and Pemberton/Salter (Group C) or Bernese-type triple pelvic osteotomy (Group D). Analysis of variance (ANOVA), t-test, chi-square test, and multivariate regression analysis were used to evaluate the independent risk factors of unsatisfactory hip function.

RESULTS

The mean hip function score was 10.8±2.8 (4.5-15); 61 hips (62.2%) had satisfactory function (23 [23.5%] excellent and 38 [38.8%] good), while 37 hips (37.8%) had unsatisfactory function (16 [16.3%] fair and 21 [21.4%] poor). Spearman correlation analysis indicated that age at surgery was negatively correlated with function score (r=-0.326, p=0.001). The age of patients with satisfactory hip function (34.5±14.2 months; range, 19.4-74.8) was significantly lower than those with unsatisfactory function (43.7±21 months; range, 20.6-95.3) (p=0.011). The hip function score in Group A (14.2±0.8; range, 12.8-15) was significantly higher than in the other three groups (p<0.001). Hip function score in patients with type III or IV AVN was significantly lower than those without AVN, or with type II AVN (p=0.001). Multivariate regression analysis confirmed age at surgery, type of surgery and AVN were negatively correlated with hip function score. Logistic regression analysis and chi-square test confirmed age and type of surgery, and AVN were independent risk factors of unsatisfactory hip function. Multivariate regression analysis found ability to squat and amount of hip flexion and abduction, significantly decreased with age at surgery; while presence of limping, amount of hip flexion, abduction, adduction and external rotation significantly decreased with type of surgery.

DISCUSSION

Age at surgery, type of surgery and severe AVN are independent risk factors for unsatisfactory hip function in patients with late-detected DDH treated by open reduction. The ability to squat, the amount of hip flexion and abduction are the main functional parameters affected by age and surgery.

LEVEL OF EVIDENCE

IV, case series.

Imaging of developmental dysplasia of the hip: ultrasound, radiography and magnetic resonance imaging

Developmental dysplasia of the hip (DDH) describes a broad spectrum of developmental abnormalities of the hip joint that are traditionally diagnosed during infancy. Because the development of the hip joint is a dynamic process, optimal treatment depends not only on the severity of the dysplasia, but also on the age of the child. Various imaging modalities are routinely used to confirm suspected diagnosis, to assess severity, and to monitor treatment response. For infants younger than 4 months, screening hip ultrasound (US) is recommended only for those with risk factors, equivocal or positive exam findings, whereas for infants older than 4-6 months, pelvis radiography is preferred. Following surgical hip reduction, magnetic resonance (MR) imaging is preferred over computed tomography (CT) because MR can not only confirm concentric hip joint reduction, but also identify the presence of soft-tissue barriers to reduction and any unexpected postoperative complications. The routine use of contrast-enhanced MR remains controversial because of the relative paucity of well-powered and validated literature. The main objectives of this article are to review the normal and abnormal developmental anatomy of the hip joint, to discuss the rationale behind the current recommendations on the most appropriate selection of imaging modalities for screening and diagnosis, and to review routine and uncommon findings that can be identified on post-reduction MR, using an evidence-based approach. A basic understanding of the physiology and the pathophysiology can help ensure the selection of optimal imaging modality and reduce equivocal diagnoses that can lead to unnecessary treatment.

Closed Reduction for Developmental Dysplasia of the Hip: Early-term Results From a Prospective, Multicenter Cohort

BACKGROUND

Closed reduction (CR) is a common treatment for infantile developmental dysplasia of the hip. The purpose of this observational, prospective, multicenter study was to determine the early outcomes following CR.

METHODS

Prospectively collected data from an international multicenter study group was analyzed for patients treated from 2010 to 2014. Baseline demographics, clinical exam, radiographic/ultrasonographic data, and history of previous orthotic treatment were assessed. At minimum 1-year follow-up, failure was defined as an IHDI grade 3 or 4 hip and/or need for open reduction. The incidence of avascular necrosis (AVN), residual dysplasia, and need for further surgery was assessed.

RESULTS

A total of 78 patients undergoing CR for 87 hips were evaluated with a median age at initial reduction of 8 months (range, 1 to 20 mo). Of these, 8 hips (9%) were unable to be closed reduced initially. At most recent follow-up (median 22 mo; range, 12 to 36 mo), 72/79 initially successful CRs (91%) remained stable. The likelihood of failure was unaffected by initial clinical reducibility of the hip (P=0.434), age at initial CR (P=0.897), or previous treatment in brace (P=0.222). Excluding those hips that failed initial CR, 18/72 hips (25%) developed AVN, and the risk of osteonecrosis was unaffected by prereduction reducibility of the hip (P=0.586), age at CR (P=0.745), presence of an ossific nucleus (P=0.496), or previous treatment in brace (P=0.662). Mean acetabular index on most recent radiographs was 25 degrees (±6 degrees), and was also unaffected by any of the above variables. During the follow-up period, 8/72 successfully closed reduced hips (11%) underwent acetabular and/or femoral osteotomy for residual dysplasia.

CONCLUSIONS

Following an initially successful CR, 9% of hips failed reduction and 25% developed radiographic AVN at early-term follow-up. History of femoral head reducibility, previous orthotic bracing, and age at CR did not correlate with success or chances of developing AVN. Further follow-up of this prospective, multicenter cohort will be necessary to establish definitive success and complication rates following CR for infantile developmental dysplasia of the hip.

LEVEL OF EVIDENCE

Level II-prospective observational cohort.

Proximal femoral growth disturbance in developmental dysplasia of the hip: what do we know?

BACKGROUND

Proximal femoral growth disturbance (PFGD) can be the most devastating complication of the treatment of development dysplasia of the hip. The reported incidence ranges from 0% to 73%. The condition involves varying degrees of growth disturbances of the femoral capital epiphysis, the physeal plate or both.

PURPOSE

This manuscript will discuss normal growth and development of the hip, the blood supply to the upper end of the femur, pathological and radiographic changes, classifications used to describe PFGD and, most importantly, the potential causes of these growth disturbances and the authors' strategies for avoiding PFGD.

NECROSIS OF THE FEMORAL HEAD AND HEALTH-RELATED QUALITY OF LIFE OF CHILDREN AND ADOLESCENTS

Objective:

To verify the impact of avascular necrosis of the femoral head on the quality of life of children and adolescents with Perthes disease and sickle cell disease.

Methods:

A comparative study including 24 children between eight and 18 years old with avascular necrosis of the femoral head secondary to Perthes disease and sickle cell disease (Group with Necrosis) and 24 children considered asymptomatic (Group without Necrosis). Clinical and sociodemographic data were collected and the PedsQL 4.0 and the Charnley score for hip dysfunction were applied.

Results:

There was no difference in the overall score and in any domain when comparing the Perthes group (global = 73.1) and the sickle cell disease group (global = 65.9). When comparing the groups with necrosis and without necrosis, the Perthes group had a lower overall score only for the Physical Functioning domain (87.5 versus 68.5); sickle cell disease group had a lower overall score (64.9 versus 79.4) and in the Physical Functioning (68.5 versus 87.5) and School Functioning (62.9 versus 73.7) domains.

Conclusion:

Avascular necrosis of the femoral head produces lower quality of life scores both in the global evaluation and in the domains Physical Functioning and School Functioning. Necrosis, bilateral lesion, and hip function were found to be associated with the loss of quality of life. Level of Evidence III, Sectional comparative study.

The early radiological effects of Dega and Pemberton osteotomies on hip development in children aged 4-8 years with developmental dysplasia of the hip

We aimed to investigate the early radiological effects of Dega and Pemberton iliac osteotomies that were performed in patients aged 4-8 years with developmental dysplasia of the hip on development of hip joint. Dega osteotomy or Pemberton osteotomy was performed in 76 hips of 58 patients because of developmental dysplasia of the hip between September 2011 and June 2015 and were evaluated retrospectively. Of a total of 76 hips, Pemberton osteotomy was performed on 39 (19 unilateral) and Dega osteotomy was performed on 37 (21 unilateral). In all hips, the acetabular index, acetabular depth ratio, centre-edge angle of Wiberg, and Reimer's index values were recorded preoperatively and at the final follow-up. We measured the surface areas of the femoral head ossific nucleus in patients with unilateral dysplastic hips and compared results before both osteotomy procedures and at the final follow-up. There were no statistically significant differences between the groups in terms of the acetabular index and acetabular depth ratio values (P>0.05) preoperatively and at the final follow-up, but the mean centre-edge angle of Wiberg and Reimer's index values showed significant statistical differences in favor of the Dega procedure (P<0.05). There was a statistically significant difference in favor of the Pemberton procedure when the mean ratio of the surface area of the femoral head ossific nucleus on the dysplastic side in relation to the normal side was compared preoperatively (P=0.042) and at the final follow-up (P=0.027) in unilateral hips. Although Dega and Pemberton osteotomies produce satisfactory radiological outcomes at early stages in children aged 4-8 years with developmental dysplasia of the hip, a higher rate in the surface area of the femoral head ossific nucleus was observed in the Pemberton osteotomy group, which also had a lower mean age than the Dega osteotomy group.

Surgical reduction of congenital hip dislocation

Surgical reduction of congenital hip dislocation is technically challenging. In our practice, surgical reduction is usually reserved for patients who have failed non-operative treatment, which is the first-line strategy. However, primary surgery may be indicated if the dislocation is diagnosed late and can be performed until 8 years of age. The reduction step is crucial. It starts with painstaking exposure of the capsule. Identifying the lower part of the acetabulum is the key to accurate repositioning of the epiphysis. The main intra-articular procedures are resection of the ligament teres, adipose tissue within the acetabular cavity, and transverse acetabular ligament; and eversion of the radially incised limbus. In patients younger than 1 year of age, surgical reduction can be performed via the anterior approach or, in some cases, the obturator approach. No complementary steps are needed. If the diagnosis is made late, in contrast, reduction of the hip must be combined with corrective procedures on the femur and acetabulum designed to stabilise the reduction before the capsulorrhaphy, with the goal of optimising hip stability and minimising the risk of residual dysplasia. Femoral shortening and derotation osteotomy was classically reserved for children older than 3 years but has now been shown to be a useful and prudent procedure in younger patients. This osteotomy decreases pressure on the epiphysis, facilitates the reduction, and diminishes the risk of recurrence and avascular necrosis of the femoral head, which are the two dreaded complications. The outcome depends on the care directed to the procedure and on the quality of postoperative management.

Timing of surgical intervention for developmental dysplasia of the hip: a randomised controlled trial (Hip 'Op)

BACKGROUND

Developmental dysplasia of the hip (DDH) is a very common congenital disorder, and late-presenting cases often require surgical treatment. Surgical reduction of the hip may be complicated by avascular necrosis (AVN), which occurs as a result of interruption to the femoral head blood supply during treatment and can result in long-term problems. Some surgeons delay surgical treatment until the ossific nucleus (ON) has developed, whereas others believe that the earlier the reduction is performed, the better the result. Currently there is no definitive evidence to support either strategy.

OBJECTIVES

To determine, in children aged 12 weeks to 13 months, whether or not delayed surgical treatment of a congenitally dislocated hip reduces the incidence of AVN at 5 years of age. The main clinical outcome measures were incidence of AVN and the need for a secondary surgical procedure during 5 years' follow-up. In addition, to perform (1) a qualitative evaluation of the adopted strategy and (2) a health economic analysis based on NHS and societal costs.

DESIGN

Phase III, unmasked, randomised controlled trial with qualitative and health economics analyses. Participants were randomised 1 : 1 to undergo either early or delayed surgery.

SETTING

Paediatric orthopaedic surgical centres in the UK.

PARTICIPANTS

Children aged 12 weeks to 13 months with DDH, either newly diagnosed or following failed splintage, and who required surgery. We had a target recruitment of 636 children.

INTERVENTIONS

Surgical reduction of the hip performed as per the timing allocated at randomisation.

MAIN OUTCOME MEASURES

Primary outcome - incidence of AVN at 5 years of age (according to the Kalamchi and MacEwen classification). Secondary outcomes - need for secondary surgery, presence or absence of the ON at the time of primary treatment, quality of life for the main carer and child, and a health economics and qualitative analysis.

RESULTS

The trial closed early after reaching < 5% of the recruitment target. Fourteen patients were randomised to early treatment and 15 to delayed treatment. Implementation of rescue strategies did not improve recruitment. No primary outcome data were collected, and no meaningful conclusions could be made from the small number of non-qualitative secondary outcome data. The qualitative work generated rich data around three key themes: (1) access to, and experiences of, primary and secondary care; (2) the impact of surgery on family life; and (3) participants' experiences of being in the trial.

LIMITATIONS

Overoptimistic estimates of numbers of eligible patients seen at recruiting centres during the planning of the trial, as well as an overestimation of the recruitment rate, may have also contributed to unrealistic expectations on achievable patient numbers.

FUTURE WORK

There may be scope for investigation using routinely available data.

CONCLUSIONS

Hip 'Op has highlighted the importance of accurate advance information on numbers of available eligible patients, as well as support from all participating investigators when conducting surgical research. Despite substantial consultation with parents of children in the planning stage, the level of non-participation experienced during recruitment was much higher than anticipated. The qualitative work has emphasised the need for appropriate advice and robust support for parents regarding the 'real-life' aspects of managing children with DDH.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN76958754.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 63. See the NIHR Journals Library website for further project information.

The correlation between Salter's criteria for avascular necrosis of the femoral head and Kalamchi's prognostic classification following the treatment of developmental dysplasia of the hip

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.

Barnhöft: a hip specific 6-item questionnaire for children

Background

Health-related quality of life instruments, both general and more disease specific, would ideally be included in the evaluation of outcome in paediatric orthopaedics. The aim of this study was to translate and culturally adapt an instrument measuring hip function and pain for Swedish children 8-15 years old with a hip disorder.

Methods

Translation of an established questionnaire for hip disorder in children, CHOHES, was performed and called Barnhöft. Retrospective and cognitive debriefing interviews were conducted with 15 healthy children to test for the comprehensibility of the instrument. Children with slipped capital femoral epiphysis (n = 25) and healthy children (n = 35) participated in further testing through test-retest and with the comparison of answers given in a general health-related quality of life test, EQ-5D-Y (www.euroqol.org). A multi-professional expert committee supervised the process and judged the content validity.

Results

The test-retest method with a weighted Cohen's kappa showed a good stability of the instrument. The construct validity for the pain domain (1-item) in EQ-5D-Y compared to the pain domain in Barnhöft showed a Spearman's correlation coefficient of 0.73. The degree of hip pain in Barnhöft was also compared with the item "doing usual activities" in EQ-5D-Y with a Spearman's correlation coefficient of 0.67.

Conclusion

Barnhöft could be used as a simple 6-item questionnaire to identify children with pain and/or functional limitations due to sequelae related to a hip disease in childhood.

Loading rates during walking in adolescents with type II osteonecrosis secondary to pelvic osteotomy

Although Pemberton osteotomy has shown a high success rate even in older children, the occurrence of osteonecrosis (ON) remains one of the most severe complications, leading to premature osteoarthritis. Patients with type II ON are characterized by a valgus deformity of the proximal femur with altered musculoskeletal conditions, affecting the ability to attenuate or sustain the impulsive loading from the ground reaction force. It remains unclear whether these conditions also predispose these patients to harmful impulsive loadings. This study aimed to bridge the gap by measuring the loading rates in the lower limbs during level walking in adolescents who were treated during their infancy for unilateral developmental dysplasia of the hip by a pelvic osteotomy, with or without having developed type II ON. Patients with type II ON were found to display increased loading rates, not only at both the affected and unaffected hip, but also at other joints of the affected limb during level walking when compared to patients without ON changes (p < 0.05). These results suggest that patients with type II ON may be at a higher risk of developing premature hip osteoarthritis that is closely related to abnormal loading rates during gait. It is suggested that regular monitoring of joint loading rates in patients with type II ON is necessary for early identification of damaging loadings, and that early intervention aimed at reducing these loadings should be considered. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2199-2206, 2016.

Is Age or Surgical Approach Associated With Osteonecrosis in Patients With Developmental Dysplasia of the Hip? A Meta-analysis

BACKGROUND

Osteonecrosis of the femoral head is a major complication that negatively impacts the clinical and radiographic long-term outcome after treatment of developmental hip dysplasia (DDH). There are conflicting results in the literature whether age at the time of closed or open reduction and a specific surgical approach are associated with osteonecrosis. Better understanding of the impact of age at reduction and surgical approach is important to reduce the risk of osteonecrosis in patients with DDH.

QUESTIONS/PURPOSES

We aimed to evaluate the association between occurrence of osteonecrosis and (1) age at closed reduction; (2) age at open reduction; and (3) medial versus anterior operative approaches.

METHODS

A systematic review identified studies reporting osteonecrosis occurrence after treatment of DDH and at least 2 years of followup. This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Methodologic quality was assessed using the methodologic index for nonrandomized studies. Generalized logistic models were used to estimate pooled odds ratios (ORs) in the meta-analysis. Sixty-six studies were included in the systematic review and 24 in the meta-analysis. Data on 481 hips treated by closed reduction and 584 hips treated by open reduction were available to evaluate the association between osteonecrosis and age. The association between osteonecrosis and operative approach was assessed using data on 364 hips treated by medial open reduction and 220 hips treated by anterior open reduction.

RESULTS

Age at reduction (> 12 months versus ≤ 12 months) was not associated with osteonecrosis after closed reduction (OR, 1.1; 95% confidence interval [CI], 0.4-3.2; p = 0.9) or open reduction (OR, 1.1; 95% CI, 0.7-1.9; p = 0.66). The overall, adjusted incidence of osteonecrosis (≥ Grade II) was 8.0% (95% CI, 2.8%-20.6%) among patients treated with closed reduction at or before 12 months of age and 8.4% (95% CI, 3.0%-21.5%) among those treated after 12 months. Similarly, the odds of osteonecrosis after open reduction did not differ between patients treated after the age of 12 months compared with those treated at or before 12 months (OR, 1.1; 95% CI, 0.7-1.9; p = 0.7). The incidence of osteonecrosis (≥ Grade II) was 18.3% (95% CI, 11.7%-27.4%) among patients who had index open reduction at or before 12 months of age and 20.0% (95% CI, 13.1%-29.4%) among those who had index open reduction after 12 months of age. Among hips treated with open reductions, there was no difference in osteonecrosis after medial versus anterior approaches (18.7% medial versus 19.6% anterior; OR, 1.1; 95% CI, 0.5-2.2; p = 0.9). Conclusions We did not find an association between closed or open reduction performed at or before 12 months of age and an increased risk of osteonecrosis of the femoral head. Delayed treatment past 1 year of age as a strategy to reduce the development of osteonecrosis was not supported by this meta-analysis. Open reduction through a medial or anterior approach may be recommended based on surgeon's preference, because we found no association between development of osteonecrosis and the type of surgical approach. However, many of the studies in the current literature are nonrandomized Level III or IV observational studies of inconsistent quality. Higher quality evidence is needed to better understand the effects of age at reduction and operative approach on the development of osteonecrosis after DDH treatment.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Developmental dysplasia of the hip: What has changed in the last 20 years?

Developmental dysplasia of the hip (DDH) describes the spectrum of structural abnormalities that involve the growing hip. Early diagnosis and treatment is critical to provide the best possible functional outcome. Persistence of hip dysplasia into adolescence and adulthood may result in abnormal gait, decreased strength and increased rate of degenerative hip and knee joint disease. Despite efforts to recognize and treat all cases of DDH soon after birth, diagnosis is delayed in some children, and outcomes deteriorate with increasing delay of presentation. Different screening programs for DDH were implicated. The suspicion is raised based on a physical examination soon after birth. Radiography and ultrasonography are used to confirm the diagnosis. The role of other imaging modalities, such as magnetic resonance imaging, is still undetermined; however, extensive research is underway on this subject. Treatment depends on the age of the patient and the reducibility of the hip joint. At an early age and up to 6 mo, the main treatment is an abduction brace like the Pavlik harness. If this fails, closed reduction and spica casting is usually done. After the age of 18 mo, treatment usually consists of open reduction and hip reconstruction surgery. Various treatment protocols have been proposed. We summarize the current practice for detection and treatment of DDH, emphasizing updates in screening and treatment during the last two decades.

Developmental Dislocation of the Hip Successfully Treated by Preoperative Traction and Medial Open Reduction: A 22-year Mean Followup

BACKGROUND

During the last 35 years, the medial approach has been reported more frequently than the anterior approach for open reduction of developmental dislocation of the hip (DDH), however, few studies have followed children treated by medial open reduction to adulthood.

QUESTIONS/PURPOSES

The purposes of our study were: (1) to assess the development of 71 completely dislocated hips after medial open reduction, the incidence of additional surgery and avascular necrosis during the followup period, and the long-term radiographic and functional results; and (2) to compare our results with those obtained by others who performed open reduction either by the medial or anterior approach.

PATIENTS AND METHODS

We retrospectively evaluated, after the end of growth, 71 hips in 52 patients who underwent open reduction by the medial approach. The mean age of the patients was 16 months (range, 3-36 months). After surgery, the hips were immobilized in 100° flexion, 60° abduction, and neutral rotation for an average of 6 months. All patients had staged clinical and radiographic followups until skeletal maturity. The length of followup averaged 22 years (range, 13-32 years).

RESULTS

In all the surgically treated hips, the acetabular index normalized by the end of growth, the incidence of avascular necrosis was 18%, and additional surgery was required in 15% of our cases. At the last followup, 93% of the hips were classified as Severin Classes I or II and 7% as Class III; 76% of the hips had an excellent result, 17% had a good result, and 7% had a fair result according to the McKay scale as modified by Barrett and colleagues.

CONCLUSIONS

Open reduction of DDH through a medial approach provided good long-term radiographic and functional results in patients 3 to 36 months old and it was the only surgery performed in 85% of our cases. Future comparative studies are needed to confirm our results, especially in older children.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

What clinimetric evidence exists for using hip-specific patient-reported outcome measures in pediatric hip impingement?

BACKGROUND

Patient-reported outcomes (PROs) are an increasingly popular research tool used to evaluate the outcomes of surgical intervention. If applied appropriately, they can be useful both for disease monitoring and as a method of assessing the efficacy of treatment. Many disorders can lead to impingement in children and adolescents, but it is not clear if any PROs have been validated to evaluate outcomes in these populations.

QUESTIONS/PURPOSES

We performed a systematic review of the literature to answer the following research questions: (1) Which hip-specific PROs are used in pediatric populations with impingement? (2) What clinimetric evidence exists for the use of these specific PROs in this population?

METHODS

We performed two systematic searches of three databases (Medline, EMBASE, and Ovid All EBM Reviews). The first search aimed to identify specific PROs that have been applied to pediatric impingement populations. The second search aimed to find clinimetric evaluations of the PROs from the first search in this population.

RESULTS

We found six hip-specific PROs applied in pediatric impingement: Harris Hip Score, modified Harris Hip Score, Iowa Hip Score, Merle d'Aubigné Hip Score, Hip Outcome Score, and Non-arthritic Hip Score. However, we found no papers validating any of these PROs in this population. Furthermore, we found no papers validating any of these PROs in any pediatric population.

CONCLUSIONS

A number of adult PROs have been applied in pediatric impingement disorders without evidence of validation in any pediatric population. Further work to develop and validate a hip-specific pediatric PRO is required.

Natural history of hip instability in infants (without subluxation or dislocation): a three year follow-up

BACKGROUND

The natural history of hip instability (without subluxation or dislocation) and treatment in infants remain controversial. We performed a retrospective cohort case-only study with blinded, prospectively collected data to assess normalization of the acetabular index in consecutive untreated infant hips with sonography instability.

METHODS

Consecutive hips meeting inclusion criteria were followed by sonography/radiography and data analyzed using tabular and regression models.

RESULTS

In 48 hips, acetabular index measured by radiography normalized within 3 years of age without treatment. Normalization by age occurred: 7 months in 35%, 12 months in 67%, 18 months in 75%, 24 months in 81%, and 36 months in 100%. Two patterns of normalization of the acetabular index were observed: group I showed ossification in a physiological range of normal by 7 months of age, and group II had delayed ossification with later normalization of the acetabular index measurement. Breech presentation (p =0.013) and cesarean delivery (p =0.004) statistically directly correlated with a later normalization.

CONCLUSIONS

The natural history of infant hip instability (without subluxation or dislocation), which is reduced at rest and unstable with stress as diagnosed by the Harcke method of sonography, has spontaneous normalization of the acetabular index within 3 years of age. We suggest three patterns of acetabular ossification in unstable infants' hips: (I) normal ossification, (II) delayed ossification with normalization of the acetabular index by age 3 years, and (III) defective secondary centers of ossification with an upward tilt of the lateral acetabular rim in adolescence.

Osteonecrosis complicating developmental dysplasia of the hip compromises subsequent acetabular remodeling

BACKGROUND

Osteonecrosis of the femoral head secondary to treatment of developmental dysplasia of the hip (DDH) affects acetabular remodeling but the magnitude of this effect is unclear.

QUESTIONS/PURPOSES

Using four measures of acetabular development, we (1) determined whether acetabular remodeling differed in hips with and without osteonecrosis; and (2) determined the impact of severity of osteonecrosis contributing to acetabular remodeling.

METHODS

We retrospectively reviewed 95 patients (118 hips) treated for DDH by closed or open reduction with or without femoral osteotomy between 1992 and 2006. We evaluated serial radiographs from the time when a stable reduction had been achieved. In 902 radiographs taken over 19 years, we measured the acetabular index and three other indices of hip development. Patients were followed for a mean of 8 years (range, 1-19 years). At last followup, 86 of the 118 hips (73%) had osteonecrosis according to the criteria by Bucholz and Ogden.

RESULTS

The acetabular index improved with time in all hips but the magnitude of improvement was larger in hips without osteonecrosis. The adjusted mean acetabular index at 14 years was 17° for hips with osteonecrosis (95% CI, 15°-18°) and 10° for hips without osteonecrosis (95% CI, 7°-13°). The lateral centering ratio improved after reduction to a normal value less than 0.85 in both groups but the rate of change with 0.06 versus 0.05 was higher in hips with osteonecrosis. The superior centering ratio was worse at all times in hips with osteonecrosis with a mean difference of 0.04. If only radiographic changes of Grades II and greater were considered osteonecrosis, the mean adjusted acetabular index at 14 years was 17.7° (15.6°-19.7°) for hips with osteonecrosis and 12.4° (10.3°-14.4°) for hips without osteonecrosis.

CONCLUSIONS

Although radiographic indices improved consistently with time in hips without osteonecrosis, hips with osteonecrosis had abnormal indices of acetabular remodeling throughout followup. Osteonecrosis of the femoral head inhibited acetabular remodeling.

LEVEL OF EVIDENCE

Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Reliability of Bucholz and Ogden classification for osteonecrosis secondary to developmental dysplasia of the hip

BACKGROUND

Osteonecrosis is perhaps the most important serious complication after treatment of developmental dysplasia of the hip (DDH). The classification by Bucholz and Ogden has been used most frequently for grading osteonecrosis in this context, but its reliability is not established and unreliability could affect the validity of studies reporting the outcome of treatment.

QUESTIONS/PURPOSE

We established the interrater and intrarater reliabilities of this classification and analyzed the frequency and nature of disagreements.

METHODS

Three pediatric hip surgeons, a musculoskeletal pediatric radiologist, and three orthopaedic trainees graded 39 radiographs (hips) according to the Bucholz and Ogden classification, blinded to any clinical data. Ratings were repeated after 2 weeks. Interrater reliability and intrarater reliability were determined using the simple kappa statistic. Grading was compared among raters, the nature and frequency of disagreements established, and subgroup analyses performed.

RESULTS

Interrater reliability was 0.34 (95% CI = 0.28, 0.40) for all raters, and 0.31 (0.20 to 0.43) for the three surgeons. The best interrater reliability was observed between the radiologist and a surgeon with a kappa of 0.51 (0.30, 0.72). Intrarater reliability estimates ranged from 0.44 to 0.69. Raters disagreed regarding the grade of osteonecrosis in 26 of 39 hips (67%), with seven of 26 disagreements (27%) involving confusion between Grades I and II.

CONCLUSIONS

The interrater reliability was lower than expected, considering the raters' experience. Distinguishing between Grades I and II was the most frequently observed problem. We believe that the low reliability was a result of an ambiguous classification scheme rather than the variability among the raters. Outcome studies of DDH based on this classification should be interpreted with caution. We recommend the development of a new classification with better prognostic ability.

LEVEL OF EVIDENCE

Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Strategies to improve outcomes from operative childhood management of DDH

The operative management of DDH is technically challenging. To achieve excellent results, surgeons need to select the most appropriate operative treatment, minimize the risk of complications, and be aggressive in the management of serious complications, such as redislocation and AVN, when they occur. We have described specific steps and strategies to assist in each of these key steps.