Developmental dysplasia of the hip: open reduction as a risk factor for substantial osteonecrosis

Risk factor analysis of femoral avascular necrosis after operation for Tönnis grade IV developmental dysplasia of the hip

PURPOSE

We explored the risk factors for avascular necrosis (AVN) after surgery using open reduction, pelvic osteotomy, and femoral osteotomy for Tönnis grade IV developmental dysplasia of the hip (DDH).

METHODS

In this retrospective study, we collected data of patients with Tönnis grade IV DDH treated with open reduction and pelvic osteotomy combined with femoral osteotomy from January 2012 to May 2020. The patients were divided into the AVN group and non-AVN group using the Kalamchi-MacEwen classification system. The clinical and imaging data of the two groups were collected, and the possible risk factors were included in the analysis. Univariate and multivariate logistic regression analyses were used to identify the independent risk factors and odds ratios of AVN.

RESULTS

In all, 254 patients (mean age; 2.6±0.9 years, 278 hips) were included. The mean follow-up time was 3.8±1.5 years. A total of 89 hips (32%) were finally classified as AVN (Kalamchi-MacEwen II-IV). Univariate analysis showed significant associations with AVN for age (p=0.006), preoperative femoral neck anteversion (FAV) (p<0.001), femoral osteotomy length to dislocation height ratio (FDR) <1 (p<0.001), and the epiphyseal ossific nucleus diameter to the neck diameter ratio (ENR) <50% (p=0.009). Multivariate logistic regression analysis showed that only excessive preoperative FAV (OR: 1.04; 95% CI: 1.02-1.05; p<0.001) and FDR<1 (OR: 3.58; 95% CI: 2.03-6.31; p<0.001) were independent risk factors for femoral head necrosis.

CONCLUSION

Excessive preoperative FAV and FDR<1 are important risk factors for femoral AVN after open reduction, pelvic osteotomy, and femoral osteotomy for Tönnis grade IV DDH. For children with DDH with high dislocation and excessive FAV, clinicians should fully evaluate their condition and design more personalized treatment programs to prevent AVN.

Open reduction after failed closed reduction following failed Pavlik harness treatment in developmental dysplasia of the hip: One- or two-stage?

INTRODUCTION

The current published evidence for the treatment of developmental dysplasia of the hip (DDH) with failed closed reduction (CR) following failed Pavlik harness (PH) treatment is still limited. This study aimed to determine whether an one-stage open reduction (OR) would lead to a similar outcome to a two-stage OR in these patients. Meanwhile, the occurrence of femoral head avascular necrosis (AVN) and further surgery (pelvic osteotomy, PO) within the follow-up period was investigated.

MATERIALS AND METHODS

A consecutive series of DDH patients who failed CR following failed PH treatment and received OR finally between January 2008 and December 2020 were studied. The patients were divided into two groups. One group of which received OR immediately after failed CR (one-stage OR group, Group A), and the other received a delayed OR (two-stage OR group, Group B). The McKay's criteria, acetabular index (AI) and the degree of dislocation of the hips were evaluated for the final outcomes.

RESULTS

At the last follow-up, 54 (84.4%) of the 64 hips in Group A and 26 (83.9%) of 31 hips in Group B were in excellent or good condition. Comparison between the two groups revealed that there were no differences in terms of McKay grading (P = 0.950), AI (P = 0.783), incidence of AVN (P = 0.745), and also incidence of PO (P = 1.000). However, a significant lower mean AI was found in Group A, when the OR was performed in Group B (31.06 ± 4.45° vs. 33.87 ± 4.12°, P = 0.004).

CONCLUSION

Both of the one- and two-stage OR may acheive favorable outcomes. Moreover, one-stage OR is of without the general anesthesia risk associated with two-stage OR. We therefore advocate that an OR should be performed in appropriate DDH patients during the same session once a failed CR is detected.

Retrospective Comparison of Outcomes Between Closed and Open Reduction for Developmental Dysplasia of the Hip in Children Aged 6-24 Months

PURPOSE

We aimed to compare the outcomes between closed reduction (CR) and open reduction (OR) in children aged 6-24 months with developmental dysplasia of the hip (DDH) who could be reduced safely and stably by the closed reduction operation.

METHODS

We retrospectively reviewed the medical records of 77 patients who underwent CR or OR for DDH. Fifty-one patients (56 hips) underwent CR, 26 (29 hips) underwent OR. The demographic data, International Hip Dysplasia Institute classification and acetabular index (AI) before reduction and the centre-edge angle (CEA), AI, Alsberg angle (AA), Reimer's migration index (RMI), and height-to-width index (HWI) of the epiphysis were compared between two groups at the final follow-up. The percentage of coxa magna > 15% of the normal side and AA > 81° were calculated.

RESULTS

At the final follow-up, the mean AA in the CR and OR groups were 77.66° (60°-89°) and 81.97° (73°-91°) (p = 0.001), respectively, there were 32.14% and 58.62% of the hips with an AA > 81° (p = 0.019). The frequency of coxa magna > 15% of the normal side was higher in the OR group (60.9%) than in the CR group (6.5%) (p < 0.001). There was no difference in the improvement of AI, CEA, HWI, and RMI.

CONCLUSION

In children aged 6-24 months with DDH, if a stable and safe CR can be obtained but with medial joint space up to 6mm, CR should be attempted first.

Avascular necrosis under different treatment in children with developmental dysplasia of the hip: a network meta-analysis

The objective of this study was to evaluate the incidence of avascular necrosis (AVN) of the femoral head in children less than 3 years of age with developmental dysplasia of the hip (DDH) treated with closed reduction, open reduction alone and open reduction combined with osteotomy. We reviewed clinical trials from the PubMed, EMBASE and Cochrane Library databases (up to November 2020) that were related to closed reduction, open reduction alone and open reduction combined with osteotomy for the treatment of children under 3 years of age with DDH. The screening and quality evaluation of the literature were performed independently by two researchers. In case of disagreement, a third researcher resolved the discourse. Finally, the data were extracted, and the R software and GeMTC program package were used to conduct a network meta-analysis (NMA). The evaluation index was the incidence of AVN. Fourteen articles were included. The NMA showed that in terms of the incidence of AVN, cases treated with open reduction alone were higher than those with closed reduction, and the difference was statistically significant. Open reduction alone had the highest probability (94.4%) of having the highest incidence of AVN, followed by open reduction combined with osteotomy (5.5%) and closed reduction (0.1%). In the treatment of children with DDH who are younger than 3 years old, open reduction alone is most likely to be the treatment with the highest incidence of AVN, followed by open reduction combined with osteotomy. The closed reduction had the smallest probability of AVN.

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.

DDH in the Walking Age: Review of Patients with Long-Term Follow-Up

INTRODUCTION

The best treatment option in children with late detected DDH is still a subject of much controversy and only few studies have investigated the long-term outcome of treatment in such patients. We performed a systematic review to assess long-term outcome of late detected DDH hips treated after walking age.

METHODS

Studies met inclusion criteria if they: (1) reported at least 30 hips treated; (2) included children aged between 9 months and 12 years; (3) treatment indication was late detected DDH after walking age; (4) presented a minimum follow-up of 10 years; (5) reported a clinical or radiological outcome. The Kaplan-Meier method was used to evaluate long-term survival according to clinical and radiological outcomes. The rate of total hip replacement (THR) was retrieved.

RESULTS

From a total of 6561 articles, 13 articles with grade IV level of evidence were included in our review. A total of 988 hips in 800 patients with a mean follow-up of 27.9 years (range 10-67) were included. The mean age at surgery was 3.3 years (range, 9 months-12 years). The rate of THR increased according to the length of final follow-up. In particular, all studies reported no case of THR at 23.5 years of follow-up, a rate of 10.2% of THR between 30 and 40 years of follow-up and a rate of 35.6% of THR in patients with follow-up more than 40 years.

CONCLUSIONS

In patients with late detected DDH, most THR became necessary more than 30 years after the index procedure and their number increased further after 40 years and more of follow-up. Late detected DDH diagnosed after walking age is a life-long disease.

Effect of age on radiographic outcomes of patients aged 6-24 months with developmental dysplasia of the hip treated by closed reduction

This study aimed to investigate the effect of age on the rates of redislocation, avascular necrosis (AVN) of the femoral head, and final radiographic outcomes in patients with developmental dysplasia of the hip (DDH) treated with closed reduction. A total of 308 hips (276 patients) with DDH treated with closed reduction were included and divided into three groups according to age (<12, 12-18, 18-24 months). Tönnis grade, rate of redislocation and AVN, Severin radiographic grade, and risk of surgery were evaluated on radiographs. Tönnis grade significantly increased with age (P < 0.001). Redislocation occurred in 17 (5.5%) and AVN occurred in 36 (11.7%) hips. The rate of redislocation and AVN was similar among the three age groups in all Tönnis grades. However, redislocation rate significantly increased with Tönnis grade (P = 0.027). Overall, 246 hips (79.9%) had satisfactory final outcomes, and 62 hips (20.1%) had unsatisfactory outcome; no difference was observed among three age groups. A total of 103 hips (33.4%) were found to be at risk for secondary surgery. The surgical risk (25%) in patients younger than 12 months was lower than that of older patients (12-18 months: 34.4%; 18-24 months: 37.9%). Logistic regression analysis also confirmed that age was not a risk factor for redislocation, AVN, or poor radiographic outcome. In conclusion, age has no significant impact on redislocation and AVN in patients aged 6-24 months with DDH treated by closed reduction. Although older patients have a higher risk developing residual acetabular dysplasia, secondary pelvic surgery provides favorable outcomes in most patients.

Closed vs open reduction in developmental dysplasia of the hip: The short-term effect on acetabular remodeling

BACKGROUND

This study aims to assess acetabular remodeling following closed vs, open hip reduction in children younger than 2 years of age.

METHODS

Records of children with DDH, who underwent closed or open reduction, were reviewed. Acetabular index (AI) was measured on radiographs taken prior to reduction and on outcome radiographs taken at age 4 years. Radiographic outcomes were analyzed and residual dysplasia (outcome AI ≥ 30) degrees recorded.

RESULTS

42 hips had closed reduction; and 26 hips had open reduction. A higher percentage of hips treated with successful closed reduction, had outcome AI ≥ 30° (29% vs. 19% p = 0.387). Residual dysplasia was more common in IHDI-IV hips than IHDI-III hips for both groups. A higher incidence of AVN was seen in the open reduction group (13% vs. 7%; p = 0.43).

CONCLUSION

In children with DDH under the age of two, open reduction with capsulorrhaphy may benefit acetabular remodeling more so than closed reduction despite maintenance of reduction. Although AVN remains a risk, higher remodeling might be expected with open reduction.

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.

Radiographic outcome of children older than twenty-four months with developmental dysplasia of the hip treated by closed reduction and spica cast immobilization in human position: a review of fifty-one hips

PURPOSE

This study aimed to investigate the radiographic outcomes, rate of redislocation, and avascular necrosis of proximal femoral epiphysis (AVN) in patients aged 24 to 36 months with developmental dysplasia of the hip (DDH) treated by closed reduction (CR) and spica cast immobilization in human position.

MATERIAL AND METHODS

We reviewed the medical records of 39 patients (51 hips) aged 24 to 36 months with DDH treated by CR and spica cast immobilization in human position. The Tönnis grade, rate of redislocation and AVN, acetabular index (AI), centre-edge angle (CEA), and Severin radiographic grade were evaluated on plain radiographs.

RESULTS

Among the included 39 patients (51 hips), 15 hips (29.4%) were Tönnis grade II, 24 hips (47.1%) were grade III, and 12 hips (23.5%) were grade IV. In 47 hips (92.2%), the ossific nucleus was present at the time of CR. Stable reduction was achieved by CR in 39/51 hips (76.5%) and redislocation occurred in 12/51 hips (23.5%). Among the 12 hips that redislocated, 11 underwent open reduction and one repeated CR. Two out of 40 hips (5%) treated by CR developed AVN. Overall, 54.6% of the hips had satisfactory outcomes (39.2% Severin type I and 17.6% type II), while 45.4% had unsatisfactory outcomes (39.2% Severin type III and 3.9% type IV). Of the 40 hips treated by CR, 57.5% and 42.5% of cases had satisfactory outcomes and residual acetabular dysplasia, respectively. Six out of 11 hips (54.6%) treated by open reduction and pelvic osteotomy had satisfactory outcomes.

CONCLUSIONS

Our study showed that stable CR could be achieved in 76.5% of patients aged 24 to 36 months with DDH at the time of index procedure. Satisfactory outcomes can be expected in 56.4% of the cases (5.0% AVN rate), although late acetabular dysplasia may develop in 43.6% of the hips.

Prognostication in Developmental Dysplasia of the Hip Using the Ossific Nucleus Center Edge Angle

BACKGROUND

The aim of this paper was to determine the prognostic potential of the ossific nucleus center edge angle (ONCEA) in patients below 5 years of age treated for developmental dysplasia of the hip (DDH) to predict final outcome and the need for a secondary procedure.

METHODS

The interobserver and intraobserver reliability was calculated using the intraclass correlation coefficient for measurement of the ONCEA. The ONCEA was divided a priori into 3 groups: group A≥10 degrees, group B -9 to 9 degrees, and group C ≤-10 degrees. Final outcome was measured using the McKay score and Severin classification. The presence of osteonecrosis was recorded at final follow-up.

RESULTS

One hundred one patients with 133 dislocated hips underwent closed or open reduction for DDH. Mean age at presentation was 19 months with a mean age at final follow-up of 12.4 years. A significant difference was shown in a comparison of the 3 ONCEA groups using the McKay score, Severin classification, and need for a secondary procedure. Eighty seven of the 101 patients underwent ONCEA reliability measurements. The ONCEA was shown to have a mean intrarater reliability of 0.89, and a mean interrater reliability of 0.77.

CONCLUSIONS

The ONCEA is a reliable measurement in predicting medium-term outcome of the hip post reduction in children under the age of 5 years with DDH and might be useful as a predictor for a secondary procedure before the age of 5 years.

LEVEL OF EVIDENCE

Level III-prognostic case control study.

CLINICAL RELEVANCE

This case control study shows the importance of measuring the ONCEA within 6 months of removing the final cast after reduction of a dislocated hip and its implications for further management and outcome.

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.

Long-term outcome after anterolateral open reduction and Salter osteotomy for late presenting developmental dysplasia of the hip

INTRODUCTION

Only a handful of studies report outcomes after open reduction for developmental hip dislocation beyond skeletal maturity. For successfully reduced hips it is the outcome into late adulthood on which the results of this intervention should be judged. These studies indicate clearly the importance of preservation of the acetabular growth centres during surgery. The acetabulum must also be addressed when insufficient growth remains reliably to remodel residual dysplasia even after stable, concentric reduction.

SUMMARY

Comparing the longest-term outcome studies for open reduction to less invasive, but mainly historical, techniques of gradual traction reduction it is unsettling to note that the latter protocols are associated with the best results. Whereas open reduction and innominate osteotomy are practised as originally described by Salter, gradual traction reduction has largely been abandoned.

CONCLUSIONS

There are probably aspects of the more time-consuming methods of gradual reduction that do not violate the hip joint capsule that expose the femoral head to a lower risk of femoral head osteonecrosis leading to better long-term outcomes.

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.

Association between open or closed reduction and avascular necrosis in developmental dysplasia of the hip: A PRISMA-compliant meta-analysis of observational studies

BACKGROUND

The risk of avascular necrosis of the femoral head (AVN) after treatment of developmental dysplasia of the hip is associated with the method of reduction. Some authors have suggested that open reduction is a risk factor for AVN; however, this is controversial. To our knowledge, a quantitative comparison of the incidence of AVN between closed and open reduction has not been conducted.

METHODS

Published studies were identified by searching PubMed, EMBASE, and the Cochrane Library up to May, 2015, focusing on the incidence of AVN after closed or open reduction for developmental dysplasia of the hip in children aged <3 years. Patients were age-matched who were treated by either closed or open reduction, but without pelvic or femoral osteotomy. Two authors independently assessed eligibility and abstracted data. Discrepancies were discussed and resolved by consensus. We pooled the odds ratios (ORs) and 95% confidence intervals (95%CIs) from individual studies using a random-effects model and evaluated heterogeneity and publication bias.

RESULTS

Nine retrospective studies were included in this analysis. The pooled OR for comparing open reduction with closed reduction for all grades of AVN was 2.26 (95%CI = 1.21-4.22), with moderate heterogeneity (I = 44.7%, P = 0.107). The pooled OR for grades II to IV AVN was 2.46 (95%CI = 0.93-6.51), with high heterogeneity (I = 69.6%, P = 0.003). A significant association was also found for the further surgery between open and closed reduction, with a pooled OR of 0.30 (95%CI = 0.15-0.60) and moderate heterogeneity (I = 46.4%, P = 0.133). No evidence of publication bias or significant heterogeneity between subgroups was detected by meta-regression analyses.

CONCLUSION

Findings from this meta-analysis suggest that open reduction is a risk factor for the development of AVN compared with closed treatment. Future studies are warranted to investigate how open reduction combined with pelvis and/or femoral osteotomy affects the incidence of AVN.

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.

Early treatment with the von Rosen splint for neonatal instability of the hip is safe regarding avascular necrosis of the femoral head: 229 consecutive children observed for 6.5 years

BACKGROUND AND PURPOSE

Avascular necrosis of the femoral head (AVN) is a complication in treatment of developmental dysplasia of the hip (DDH). We evaluated the risk of AVN after early treatment in the von Rosen splint and measured the diameter of the ossific nucleus at 1 year of age.

CHILDREN AND METHODS

All children born in Malmö, Sweden, undergo clinical screening for neonatal instability of the hip (NIH). We reviewed 1-year radiographs of all children treated early for NIH in our department from 2003 through 2010. The diameter of the ossific nucleus was measured, and signs of AVN were classified according to Kalamchi-MacEwen. Subsequent radiographs, taken for any reason, were reviewed and a local registry of diagnoses was used to identify subsequent AVN.

RESULTS

229 of 586 children referred because of suspected NIH received early treatment (age ≤ 1 week) for NIH during the study period. 2 of the 229 treated children (0.9%, 95% CI: 0.1-3.1) had grade-1 AVN. Both had spontaneous resolution and were asymptomatic during the observation time (6 and 8 years). 466 children met the inclusion criteria for measurement of the ossific nucleus. Neonatally dislocated hips had significantly smaller ossific nuclei than neonatally stable hips: mean 9.4 mm (95% CI: 9.1-9.8) vs. 11.1 mm (95% CI: 10.9-11.3) at 1 year (p < 0.001).

INTERPRETATION

Early treatment with the von Rosen splint for NIH is safe regarding AVN. The ossification of the femoral head is slower in children with NIH than in untreated children with neonatally stable hips.

Early predictors of acetabular growth after closed reduction in late detected developmental dysplasia of the hip

This study evaluates improvement of the acetabular index (AI) in patients with developmental dysplasia of the hip at 4 years after closed reduction, and determines the association between the final AI and a set of factors. Sixty-two patients (74 hips) treated with closed reduction were categorized into three groups according to age: group A (0-12 months, 18 hips), group B (13-18 months, 24 hips), and group C (>18 months, 32 hips). There was no difference in AI among the three groups before reduction (P=0.293). In groups A and C, the AI decreased significantly over time until 3 years after reduction and no differences were observed between the time points of 3 and 4 years. At 4 years after reduction, the AI of group C was significantly higher than that of groups A (P<0.001) and B (P=0.012). The overall AI improvement rate was 28.63%. The AI improvement rate of group A was significantly higher than that of group C (P=0.005). Pearson correlation analysis indicated no correlation between center-head distance discrepancy and the final AI (P=0.811). Linear regression suggested that age and initial AI correlated significantly with the final AI (R=0.617, F=15.031, P<0.001). Other factors, such as sex, center-edge angle of Wiberg, bilaterally involved, and avascular necrosis of the femoral head, showed no correlations with the final AI (P>0.05). According to the coefficients, initial AI (β1=0.432, P<0.001) had greater effect than age (β2=0.197, P=0.023) on the final AI. In conclusion, the AI decreases in all patients after reduction and stabilizes at 3 years after reduction. The AI improvement rate is correlated negatively with age. Age and initial AI are early predictors of the progress of AI after closed reduction in developmental dysplasia of the hip patients.

The medial approach for the treatment of children with developmental dysplasia of the hip

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.

Long-term outcome of gradual reduction using overhead traction for developmental dysplasia of the hip over 6 months of age

BACKGROUND

In children over 6 months of age with developmental dysplasia of the hip (DDH), achieving a concentrically reduced hip while avoiding avascular necrosis (AVN) is challenging. The utility of gradual reduction (GR) using traction has insufficient evidence. We therefore report the long-term outcome of GR using overhead traction (OHT).

METHODS

We retrospectively reviewed 67 patients with DDH (75 hips) treated with GR using OHT over 6 months of age. The age at reduction ranged from 7 months to 4 years. All patients were followed up until skeletal maturity with a mean duration of 15.6 years. Pelvic radiographs were used to assess AVN, acetabular development, and the Severin classification. We determined the factors affecting the outcome at skeletal maturity.

RESULTS

Seventy-two hips (96%) were successfully reduced, 2 required subsequent closed reduction and 1 underwent open reduction. AVN occurred in 2 hips (2.7%). Among 48 hips (64%) with residual acetabular dysplasia, 31 were treated with Salter innominate osteotomy (SIO) between 5 and 6 years of age. Finally, 62 hips (82.7%) showed satisfactory outcome (56 in Severin class I and 6 in class II), whereas 13 showed unsatisfactory outcome (class III). Although we found no significant factors affecting the outcome, most of the hips treated with SIO were included in the satisfactory group.

CONCLUSIONS

GR using OHT could effectively minimize the risk of developing AVN in patients with DDH over 6 months of age at presentation. SIO at preschool age may play a beneficial role in the long-term outcome of GR using OHT.

Retrospective radiographic evaluation of treatment results of developmental dysplasia of the hip in walking-age children

We evaluated treatment results of 22 children (32 hips) with idiopathic hip dislocation after walking age in two Dutch academic hospitals. The Tönnis classification was used preoperatively. Outcome was measured using the Severin and Kalamchi classification. The mean age at treatment was 24 months and the mean follow-up was 6.8 years. In 24 hips (73%), a perfect outcome was found (Kalamchi score≤1 and Severin score of 1). A fair or a poor outcome according to Severin (≥3) was found in five hips (15%). Treatment of a hip dislocation beyond 18 months of age usually results in adequate hip development with limited avascular necrosis.

LEVEL OF EVIDENCE

Level III.

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.