The prognostic importance of the ossific nucleus in the treatment of congenital dysplasia of the hip

Outcomes of treatment for developmental dislocation of the hip when the Pavlik method has failed

OBJECTIVES

Despite the success rate of the Pavlik method in the treatment of developmental dislocation of the hip, there is a subset of hips that do not reduce with harness use. The purpose of this study was to determine the outcomes after closed reduction (CR), open reduction (OR) and combined open reduction and pelvic osteotomy (OR+PO) in patients with infantile hip dislocations who initially failed the Pavlik method.

METHODS

This was a retrospective cohort study of patients with infantile hip dislocations who failed the Pavlik method and subsequently underwent a secondary procedure for persistent hip dislocation. The primary outcome measure was the Severin classification of the involved hip 3 years after the secondary procedure. Other outcomes assessed included rates of redislocation, residual acetabular dysplasia and proximal femoral growth disturbance.

RESULTS

Twenty-three patients were included; seven subsequently underwent CR, three underwent isolated OR and 13 proceeded directly to OR+PO. The overall successful outcome rate at final follow-up (as determined by radiographic Severin class I or II) was 11/23 (48%). However, patients undergoing OR+PO had significantly higher rates of successful outcomes (77%) compared with CR (15%) and OR (0%), P  < 0.05. The rate of residual acetabular dysplasia and proximal femoral growth disturbance was significantly lower in patients treated with OR+PO compared with CR and isolated OR, P  < 0.05.

CONCLUSION

Patients with dislocated hips who failed Pavlik harness treatment had better radiographic outcomes 3 years after OR+PO in comparison to patients undergoing CR or isolated OR.

Severity of hip dysplasia as the major factor affecting outcome of closed reduction in children with hip dysplasia

The objective of this study was to analyze a multicenter cohort of children with developmental dysplasia of the hip (DDH) who underwent treatment with closed reduction. We sought to report the effects that severity of hip dysplasia and age have on the development of femoral head avascular necrosis (AVN) and the need for additional procedures. All patients with DDH and minimum 2 years of follow-up who underwent closed reduction were identified. The following variables were recorded: sex, laterality of hip involvement, age, acetabular index (AI), and International Hip Dysplasia Institute (IHDI) grade. The effects of patient age and pre-procedure IHDI grade on the rate of AVN and need for additional procedures after the closed reduction were analyzed using an alpha of 0.05. Seventy-eight total hips were included in the final analysis. The average patient age was 12 months. AVN of the femoral head was reported in 24 hips (30.8%) and 32 hips (41.0%) required additional surgery. Higher pre-op IHDI grade was associated with higher risk of developing Bucholz-Ogden grades II-IV AVN of the femoral head ( P = 0.025) and requiring additional surgery ( P = 0.033) regardless of patient age. There were no statistically significant differences for the effect of age on the measured outcomes ( P  > 0.05). These findings suggest that severity of dislocation (IHDI grade) is a significant risk factor for the development of AVN and need for additional procedure.

A novel quantitative approach to evaluate femoral head perfusion by contrast-enhanced ultrasound: A pilot study in infants with developmental dysplasia of the hip

Avascular necrosis (AVN) is a major morbidity that can occur after surgical reduction of a hip with developmental dysplasia. Early detection of changes in femoral head perfusion during surgery may help detect a hip at risk for AVN and guide intraoperative management. Contrast-enhanced ultrasound (CEUS) can be employed for visualization of femoral head perfusion. In this study we evaluate a quantitative CEUS technique to assess femoral head perfusion pre- and post-surgical reduction. CEUS images were obtained following a bolus injection of an ultrasound contrast agent, prior to and again following surgical reduction and casting. An image processing technique called delta projection was used to quantify hip perfusion, measuring peak enhancement (PE) and perfusion index (PI). We analyzed CEUS images of the hips of eight patients, including seven females, whose ages ranged from 4 months to 1 year. In five hips, perfusion increased following surgery, with a mean pre-surgery PE of 6.7 ±2.5(± SE) and PI of 10.5 ±6.3; and a post-reduction PE of 13.1±6.1 (p=0.07) and PI of 14.2 ±6.2 (p=0.008). The change in contrast visualization was observed to be greater within the central aspect of the cartilaginous femoral epiphysis. The proposed technique can quantify pre- and post-surgical perfusion changes on CEUS images in patients with developmental dysplasia. This quantitative technique may provide a more objective and accurate assessment of changes in femoral head perfusion that may have the potential to be indicative of the risk of developing AVN.

Outcomes of Open Reduction in Children With Developmental Hip Dislocation: A Multicenter Experience Over a Decade

BACKGROUND

Open reduction of the hip is commonly performed in children with severe developmental dysplasia of the hip, or in cases that are refractory to nonoperative forms of treatment. The open reduction has been associated with numerous complications including avascular necrosis (AVN) of the femoral head, the need for reoperation, and residual radiographic dysplasia. This study seeks to determine the effects of preoperative severity of dysplasia, associated procedures (femoral and acetabular osteotomies), age on AVN, and the need for reoperation.

METHODS

Children with developmental dysplasia of the hip and a minimum of 2 years of follow-up who underwent open reduction were identified. The following data points were recorded: sex, laterality of hip involvement, simultaneous procedures, surgical approach used, age, acetabular index, and International Hip Dysplasia Institute grade. We analyzed the effects of preoperative International Hip Dysplasia Institute, age, surgical approach (anterior/medial), bilateral reduction, and simultaneous femoral shortening or pelvic osteotomy on the outcomes of AVN and reoperation.

RESULTS

One hundred eighty-five hips in 149 patients were included in this study with an average follow-up of 4 years (range: 2 to 5 y). The average age at index surgery was 23 months (range: 1 to 121 mo). Overall, 60 hips (32.4%) required secondary surgical procedures at an average age of 58.5 months. High-grade AVN was noted in 24 hips (13.0%) and was found to be associated with the severity of the hip dislocation ( P = 0.02). A higher rate of reoperation was found in children over 18 months at the time of open reduction who did not receive an acetabular osteotomy ( P = 0.012).

CONCLUSION

Approximately 1/3 of patients require another operative intervention within the first 4 years after open reduction of the hip. We found the severity of hip dislocation to be associated with a higher risk of AVN development. These findings support performing an acetabular osteotomy in children over 18 months of age at the time of open reduction to decrease the likelihood of requiring future reoperation during the first 4 years after the index procedure.

LEVEL OF EVIDENCE

Level III.

A Prospective, Multicenter Study of Developmental Dysplasia of the Hip: What Can Patients Expect After Open Reduction?

BACKGROUND

Although there are several predominantly single-center case series in the literature, relatively little prospectively collected data exist regarding the outcomes of open hip reduction (OR) for infantile developmental dysplasia of the hip (DDH). The purpose of this prospective, multi-center study was to determine the outcomes after OR in a diverse patient population.

METHODS

The prospectively collected database of an international multicenter study group was queried for all patients treated with OR for DDH. Minimum follow-up was 1 year. Proximal femoral growth disturbance (PFGD) was defined by consensus review using Salter's criteria. Persistent acetabular dysplasia was defined as an acetabular index >90th percentile for age. Statistical analyses were performed to compare preoperative and operative characteristics that predicted re-dislocation, PFGD, and residual acetabular dysplasia.

RESULTS

A cohort of 232 hips (195 patients) was identified; median age at OR was 19 months (interquartile range 13 to 28) and median follow-up length was 21 months (interquartile range 16 to 32). Re-dislocation occurred in 7% of hips (n=16/228). The majority (81%; n=13/16) occurred in the first year after initial OR. Excluding patients with repeat dislocation, 94.5% of hips were IHDI 1 at most recent follow-up. On the basis of strict radiographic review, some degree of PFGD was present in 44% of hips (n=101/230) at most recent follow-up. Seventy-eight hips (55%) demonstrated residual dysplasia compared with established normative data. Hips that had a pelvic osteotomy at index surgery had about half the rate of residual dysplasia (39%; n=32/82) versus those without a pelvic osteotomy with at least 2 years follow-up (78%; n=46/59).

CONCLUSIONS

In the largest prospective, multicenter study to date, OR for infantile DDH was associated with a 7% risk of re-dislocation, 44% risk of PFGD, and 55% risk of residual acetabular dysplasia at short term follow-up. The incidence of these adverse outcomes is higher than previous reports. Patients treated with concomitant pelvic osteotomy had lower rates of residual dysplasia. These prospectively collected, multicenter data provide better generalizable information to improve family education and appropriately set expectations.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Risk Factors for Avascular Necrosis After Closed Reduction for Developmental Dysplasia of the Hip

BACKGROUND

Avascular necrosis (AVN) is a major complication after closed reduction for developmental dysplasia of the hip. The factors that predispose to AVN remain controversial. The purpose of this study was to analyze the risk factors, especially patient factors, such as age at reduction, grade of dislocation, and ossific nucleus development, related to AVN.

MATERIALS AND METHODS

We retrospectively reviewed children with dysplasia of the hip treated by closed reduction between 1997 and 2006. AVN was evaluated using Salter criteria and Kalamchi and MacEwen classification. Related factors were analyzed.

RESULTS

One hundred and eight children (140 hips) with an average age of 16.6 months at closed reduction (range: 6-24 mo) were included in the study. For an average duration of 10.1 years (range 7-16 y) of follow-up, 44 hips (31.4%) developed AVN. Grade II or higher AVN occurred in 14 hips (10%). The incidence of AVN increased with the grade of dislocation ( P =0.022) and underdevelopment of the ossific nucleus ( P <0.001). Underdevelopment of the ossific nucleus was also found to be positively correlated with the dislocation grade ( P =0.047). The age at the time of reduction, sex, and side were not significant factors. Children who underwent secondary operation were all older than 1 year at reduction.

CONCLUSIONS

High-grade dislocation correlates with the underdevelopment of the ossific nucleus. Patients with these 2 characteristics are predisposed to AVN. As underdevelopment of the ossific nucleus occurred regardless of age, it is not advisable to delay reduction because it does not alter the AVN rate, and instead, it increases the secondary operation rate.

LEVEL OF EVIDENCE

Level IV case series.

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.

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.

Interobserver and Intraobserver Reliability in the Salter Classification of Avascular Necrosis of the Femoral Head in Developmental Dysplasia of the Hip

BACKGROUND

Avascular necrosis (AVN) of the femoral head is a concerning complication that can result from treatments for developmental dysplasia of the hip (DDH). AVN can lead to degenerative osteoarthritis, persistent acetabular dysplasia, reduced function, and continuing hip pain. The incidence of AVN reported in the DDH literature is widely varied (0% to 73%). This variability may arise from lack of consensus on what constitutes true AVN in this patient population, and lack of clear criteria provided in studies reporting incidence rates.

METHODS

A multicentre, prospective database of infants diagnosed with DDH between 2010 and 2014 from 0 to 18 months of age was analyzed for patients treated by closed reduction (CR). Twelve pediatric orthopaedic surgeons completed 2 rounds of AVN assessments. Deidentified anteroposterior radiographs at most recent follow-up were provided to surgeons along with patient age at radiographic assessment, length of follow-up, ands affected hip. Ten of 12 surgeons completed a third round of assessments where they were provided with 1 to 2 additional radiographs within the follow-up period. Radiographic criteria for total AVN described by Salter and colleagues were used. Surgeons rated the presence of AVN as "yes" or "no" and kappa values were calculated within and between rounds.

RESULTS

A total of 69 hips in 60 patients were assessed for AVN a median of 22 months (range: 12 to 36) post-CR. Interobserver kappa values for rounds 1, 2, and 3 were 0.52 (range: 0.11 to 0.90), 0.61 (range: 0.21 to 0.90), and 0.53 (range: 0.10 to 0.79), respectively. Intraobserver agreement for AVN diagnosis was an average of 0.72 (range: 0.31 to 0.96).

CONCLUSIONS

Despite using the most commonly referenced diagnostic criteria, radiographic diagnosis of AVN following CR in DDH patients demonstrated only moderate agreement across surgeons. The addition of sequential radiographs did not improve cross-observer reliability, and while substantial agreement was seen within observers, the range of intraobserver kappa values was large.

LEVEL OF EVIDENCE

Level I-diagnostic study.

Narrative Review of Complications Following DDH Treatment

BACKGROUND

The purpose of this narrative review was to survey the literature for common complications following treatment of DDH in children less than 4 years old.

METHODS

The Pubmed database was queried. Search result titles were reviewed to identify papers that were pertinent to the topic. Abstracts for these papers were obtained and read, and a subset of these were selected for review of the complete manuscript.

RESULTS

92 manuscripts were reviewed. Residual dysplasia, redislocation, and osteonecrosis are the primary complications of treatment in this age group. In the long term, hips without complications related to DDH treatment tend to do well, although a significant percentage of them will inevitably require joint replacement surgery.

CONCLUSION

Although there is excellent potential for a good outcome when DDH is diagnosed and treated under age 4 years, osteonecrosis continues to be a concern with all treatment methods. A subset of patients from this young cohort will continue to have residual dysplasia or recurrent dislocation requiring return to the operating room.

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.

Impact of presence of ossific nucleus on results of closed reduction in treatment of developmental dysplasia of the hip (302 hips)

Closed reduction is an effective treatment method for developmental dysplasia of the hip (DDH). Still, there are certain controversial issues regarding the timing of the treatment. In this study, we investigated the results of closed reduction and Outcomes of 302 hips of 218 patients treated with closed reduction have been analyzed retrospectively. One hundred fifty-two hips that had ossific nucleus [ossific nucleus (+)] during reduction have been compared with 150 hips that had no ossific nucleus [ossific nucleus (-)] during reduction. Also, the patients have been divided into two groups, the patients treated with closed reduction before the sixth month and the patients treated with closed reduction after the sixth month. Groups have been compared between themselves in terms of avascular necrosis (AVN) and redislocation. Seventy-seven of the 112 hips treated with closed reduction in the first six months were ossific nucleus (-), and AVN has been noted in 5 (6%) patients. However, although no AVN has been seen in any of the 35 ossific nucleus (+) hips, no statistically significant difference has been found between two groups. Seventy-three of the 190 hips treated with closed reduction after the sixth month were ossific nucleus (-), and AVN has been seen in 13 (17%) of these hips. AVN has been seen in 9 (7%) of the 117 ossific nucleus (+) hips. The AVN ratio was found significantly lower in the ossific nucleus (+) hips (P < 0.034). Although the presence of ossific nucleus does not provide extra protection against AVN in before the sixth month, the presence of ossific nucleus is protective against AVN after the sixth month.

The presence of the ossific nucleus and its relation to avascular necrosis rates and the number of secondary procedures in late-presenting developmental dysplasia of the hip

Late-presenting developmental dysplasia of the hip (DDH) has an incidence reported between 0.07 and 2:1000 live births. Avascular necrosis (AVN) of the femoral head secondary to treatment of DDH is a feared complication and may lead to adverse long-term sequelae. This study aims to investigate the relationship between the ossific nucleus (ON) presence and AVN in late-presenting DDH. This is a retrospective study of prospectively collected data over a 24-year period, at a single UK centre. Late-presenting DDH who were treated surgically with a closed or open reduction were included in the series. The presence of ON was monitored, and outcomes measured included AVN and whether delaying surgery affected the number of secondary procedures. Seventy-six patients with 79 hips (mean age at presentation 13.8 months) were included in the analysis. The mean age at presentation was 13.8 months. About 45.5% of hips with no ON present developed clinically significant AVN (Kalamchi and MacEwen grades 2-4, P = 0.12), compared to 20.6% of hips with the ON present. Delaying surgery did not affect AVN rates or the number of secondary procedures. Looking at long-term outcomes, 86.7% of hips had a Severin grade of I or II and 13.3% had a grade ≥III. Factors that affected long-term outcomes were absent ON (P = 0.04) and open reduction (P = 0.03). In the multiple logistic regression model, only open reduction could increase AVN rates (P value 0.027). The presence of ON at the time of surgery may have an impact on the rate and significance of AVN. Absence of the ON at the time of reduction negatively affects long-term outcomes in late-presenting DDH.

Developmental dysplasia of the hip: can contrast-enhanced MRI predict the development of avascular necrosis following surgery?

OBJECTIVE

To investigate the performance of contrast-enhanced MRI for predicting avascular necrosis (AVN) of the treated femoral head after surgical reduction for developmental dysplasia of the hip (DDH) using qualitative and quantitative methods.

METHODS AND MATERIALS

This IRB-approved, HIPAA compliant retrospective study included 47 children who underwent same-day contrast-enhanced MRI following unilateral surgical hip reduction between April 2009 and June 2018. Blinded to the clinical outcome, 3 reviewers (2 pediatric radiologists and 1 pediatric orthopedist) independently categorized the enhancement pattern of the treated femoral head. Signal intensities, measured using regions of interest (ROI), were compared between treated and untreated hips and percent enhancements were compared between hips that developed and did not develop AVN. Post-reduction radiographs were evaluated using Salter's criteria for AVN and Kalmachi and MacEwen's classification for growth disturbance. Non-parametric tests and Fisher exact test were used to compare enhancement values between AVN and non-AVN hips. Bonferroni correction was used for multiple comparisons.

RESULTS

Ten (21%) out of the 47 children (7 boys and 40 girls; mean age 9.0 ± 4.7 months) developed AVN. Age at surgical reduction was significantly higher (p = 0.03) for hips that developed AVN. No significant differences were found in gender (p = 0.61), laterality (p = 0.46), surgical approach (p = 0.08), history of pre-operative bracing (p = 0.72), abduction angle (p = 0.18-0.44), enhancement pattern (p = 0.66-0.76), or percent enhancement (p = 0.41-0.88) between AVN and non-AVN groups.

CONCLUSION

Neither enhancement pattern nor percent enhancement predicted AVN, suggesting that post-reduction conventional MRI does not accurately distinguish between reversible and permanent vascular injury.

Timing for closed reduction procedure for developmental dysplasia of the hip and its failure analysis

Background

It remains controversial whether the older age to perform closed reduction (CR) procedure for developmental dysplasia of the hip (DDH), the higher incidence of complications. The aim of this study is to evaluate the midterm outcome of CR for DDH among different age groups, and to analyze and identify risk factors for the failure of this procedure.

Methods

Clinical data of 107 DDH patients, who received CR, were retrospectively reviewed. Data were divided into three groups according to initial treatment age (Group I: younger than 12 months; Group II: 12 months to less or equal to18 months; Group III: older than 18 months). The presence of avascular necrosis (AVN), residual acetabular dysplasia (RAD), re-dislocation, and further surgeries (FS) were observed. The risk factors were identified for those outcomes aforementioned using univariable logistic regression models. For identified risk factor age, pre-op acetabular index (AI) and post-op AI, their prediction of CR failure were evaluated by receiver operating characteristics curve (ROC).

Results

A total of 107 patients (156 hips) undergoing CR procedure were evaluated with a median age at initial reduction of 13.0 ± 5.4 months (range, 4 to 28 mo). Mean follow-up time in this study was 6.7 ± 0.8 years (range, 3–8 years). The incidence of AVN, RAD and re-dislocation was 15.4% (24/156), 17.3% (27/156) and 14.7% (23/156) respectively. For AVN, RAD and re-dislocation, the significant risk factors are pre-op IHDI IV (p = 0.033), age ≥ 18 months (p = 0.012), and pre-op IHDI IV (p = 0.004) and walking (p = 0.011), respectively. The areas under the ROC curve of each type of failures were 0.841 (post-op AI), 0.688 (pre-op AI) and 0.650 (age).

Conclusions

Severe DDH patients older than 18 months with CR procedure may result in a high risk of RAD complication. Re-dislocation is significantly associated with pre-op IHDI IV and walking. Patients, who are older than 12.5 months or have a pre-op AI of 38.7° or a post-op AI of 26.4°, are also more likely to fail of CR procedure.

Does the size of the femoral head correlate with the incidence of avascular necrosis of the proximal femoral epiphysis in children with developmental dysplasia of the hip treated by closed reduction?

PURPOSE

The purpose of this study was to identify if any correlation between size of the proximal femoral epiphysis and avascular necrosis (AVN) exists.

METHODS

We retrospectively reviewed 111 patients with developmental dysplasia of the hip treated by closed reduction (124 hips). The diameter and height of both femoral head and ossific nucleus were assessed on preoperative MRI.

RESULTS

The diameter and the height of the femoral head as well as of the ossific nucleus of the contralateral side were significantly greater than the dislocated side. AVN occurred in 21 (16.9%) out of 124 hips. The rate of AVN gradually decreased with age: 30.0% at six to 12 months, 18.2% at 12 to 18 months and 3.7% at 18 to 24 months. Spearman correlation analysis showed that age is negatively correlated with the incidence of AVN (r = -0.274; p = 0.002) and the diameter of the femoral head has a significantly negative association with the incidence of AVN (r = -0.287; p = 0.001). No significant association was observed between the incidence of AVN and height of the femoral head or size of the ossific nucleus. Hips with AVN were significantly smaller than hips without AVN.

CONCLUSIONS

The size of both the femoral head and the ossific nucleus increase with age although the dislocated femoral head is smaller compared with the contralateral side. The diameter of the femoral head and not the size of the ossific nucleus negatively correlate with the risk of AVN, with a bigger femoral head showing lower risk of AVN.

LEVEL OF EVIDENCE

III.

Intraoperative Contrast-Enhanced Ultrasound Imaging of Femoral Head Perfusion in Developmental Dysplasia of the Hip: A Feasibility Study

OBJECTIVES

Developmental dysplasia of the hip (DDH) is one of the most common developmental deformities of the lower extremity. Although many children are successfully treated with a brace or harness, some require intraoperative closed or open reduction and spica casting. Surgical reduction is largely successful to relocate the hip; however, iatrogenic avascular necrosis is a major source of morbidity. Recent research showed that postoperative gadolinium-enhanced magnetic resonance imaging (MRI) can depict hip perfusion, which may predict a future incidence of avascular necrosis. As contrast-enhanced ultrasound (CEUS) assesses blood flow in real time, it may be an effective intraoperative alternative to evaluate femoral head perfusion. Here we describe our initial experience regarding the feasibility of intraoperative CEUS of the hip for the assessment of femoral head perfusion before and after DDH reduction.

METHODS

This single-institution retrospective Institutional Review Board-approved study with a waiver of informed consent evaluated intraoperative hip CEUS in children with DDH compared to postoperative contrast-enhanced MRI. Pediatric radiologists, blinded to prior imaging findings and outcomes, reviewed both CEUS and MRI examinations separately and some time from the initial examination both independently and in consensus.

RESULTS

Seventeen patients had 20 intraoperative CEUS examinations. Twelve of 17 (70.6%) had prereduction hip CEUS, postreduction hip CEUS, and postreduction gadolinium-enhanced MRI. Seven of 12 (58.3%) were evaluable retrospectively. All CEUS studies showed blood flow in the femoral epiphysis before and after reduction, and all MRI studies showed femoral head enhancement after reduction. The CEUS and MRI for all 7 patients also showed physeal blood flow.

CONCLUSIONS

Contrast-enhanced ultrasound is a feasible intraoperative tool for assessing adequate blood flow after hip reduction surgery in DDH.

Spica MRI predictors for epiphyseal osteonecrosis after closed reduction treatment of dysplasia of the hip

Spica MRI with intravenous gadolinium contrast after closed reduction for developmental dysplasia of the hip (DDH) helps to determine successful reduction and attempts to identify patients at risk for epiphyseal osteonecrosis. The objective of our study was to evaluate spica MRI predictors for epiphyseal osteonecrosis after closed reduction. This was a retrospective study of all patients undergoing closed reduction for DDH followed by gadolinium-enhanced spica MRI between July 2011 and November 2014. Patient demographics and clinical follow-up through 2017, including the development of epiphyseal osteonecrosis and need for reintervention after the initial reduction, were recorded. MRI data included hip abduction angles and quantifying the percentage of femoral head enhancement. Twenty-five hips in 21 patients (16 girls, five boys, mean age: 0.99 years, range: 0.4-3.1 years) were included in our study. The mean follow-up period was 3 ± 1.5 years (range: 0.65-6.1 years). Eight (32%) of 25 hips went on to develop osteonecrosis. Epiphyseal osteonecrosis was more likely with less than 80% enhancement (sensitivity 87.5%, specificity 88.25%, positive predictive value 78%, negative predictive value 94%). The mean contrast enhancement for patients developing osteonecrosis compared with those who did not was 37.5 and 86.5%, respectively; P = 0.001. Immediate postspica MRI with gadolinium is a useful prognostic tool for determining future risk for epiphyseal osteonecrosis in children treated for DDH. Our data complement existing literature and suggest that even in cases with partial epiphyseal enhancement, osteonecrosis may still develop. When the epiphyseal enhancement is less than 80%, it is recommended that spica cast revision is considered.

Comparison of arthroscopic and open reduction of conservatively irreducible dislocated hips of children

PURPOSE

Children with sonographic grade IV hip dysplasia according to Graf and with failed conservative treatment usually need surgical reduction afterwards. Surgical reduction of the hip can lead to severe complications, the occurrence of residual acetabular dysplasia, osteonecrosis, redislocation and other postoperative complications. This paper investigates whether arthroscopic reduction is a promising alternative to open reduction.

METHODS

We retrospectively examined 66 patients (78 hips) who were not older than two years at the first time of surgery. Arthroscopic reduction was performed on 17 children (19 hips) and open reduction on 49 children (59 hips). Patient records were used to determine redislocation, postoperative complication and residual dysplasia. Radiographs were used to determine Tönnis classification for osteonecrosis and pathological acetabular (AC) angle for residual dysplasia. We considered data up to a two-year follow-up. Statistical evaluation was performed with binary logistic regression.

RESULTS

After arthroscopic reduction, 6% showed osteonecrosis, compared with 20% with open reduction (p = 0.334). Redislocation was not observed after arthroscopic reduction but for 29% after open reduction (p = 0.005). An improvement of femoral head coverage was achieved with residual dysplasia of 23.5% after arthroscopic reduction, compared with 62% after open reduction (p = 0.002).

CONCLUSION

The arthroscopic procedure represents a meaningful alternative to the open procedure due to a lower complication rate, a safe setting, a lower rate of residual dysplasia, no observed redislocation and occurrence of osteonecrosis only once in the arthroscopic group of developmental dysplasia of the hip. The arthroscopic procedure should be tested in further studies and in other clinics in order to broaden the empirical base.

LEVEL OF EVIDENCE

Level III (retrospective cohort study).

Bilateral Developmental Dysplasia of the Hip: Does Closed Reduction Have a Role in Management? Outcome of Closed and Open Reduction in 92 Hips

BACKGROUND

Bilateral developmental dysplasia of the hip (DDH) is believed to have a worse outcome than unilateral DDH with the optimal treatment unclear. To define indications for treatment we report a retrospective series of 92 hips (46 patients) who underwent closed reduction (CR) and/or open reduction (OR).

METHODS

A total of 58 hips in 29 patients underwent attempted CR using our standardized protocol. In the same 12 year time period, 54 hips in 27 patients underwent an OR. Outcome measures included resolution of acetabular dysplasia, need for further surgery, development of osteonecrosis (ON), and modified Severin Grade.

RESULTS

CR was successful in 57% of hips; in this group secondary surgery was required in 15% and ON was seen in 12%. In the OR group, 11% failed to stabilize and required further early surgery: ON rate was 15% overall, and secondary surgery was required in 5%. In Tonnis 2/3 hips younger than 2 years, Severin grading was comparable following CR and OR, with 92% and 90% graded as Severin 1, respectively. The rate of significant ON was higher after CR in Tonnis 2/3 hips (12%) than after OR (0%). Overall, Tonnis 4 hips did badly: 94% failed CR and following OR, further surgery for redislocation/residual dysplasia was required in 21%.

CONCLUSIONS

CR can be successful in Tonnis 2/3 bilateral hips, with acceptable rates of secondary surgery, ON, and Severin grading, the latter equivalent to open reduction. Importantly, persisting with casting of a unilateral dislocation, to allow the contra-lateral hip to stabilize, does not have an adverse effect. CR is not advised in Tonnis 4 bilateral hips. Parents should be counseled that the outcome of surgery for bilateral hips is not as good as for unilateral DDH, particularly for Tonnis 4 hips which are more difficult to stabilize and more likely to require supplementary surgery even after open reduction.

LEVEL OF EVIDENCE

Level IV-Therapeutic Study.

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.

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.

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.

Presence of the Ossific Nucleus and Risk of Osteonecrosis in the Treatment of Developmental Dysplasia of the Hip: A Meta-Analysis of Cohort and Case-Control Studies

BACKGROUND

Concern for increased risk of osteonecrosis in hips with an absent ossific nucleus has led some surgeons to delay reduction in the treatment of developmental dysplasia of the hip (DDH) until the ossific nucleus is present. A previous meta-analysis reported a potential protective effect against high-grade osteonecrosis (II to IV) when the ossific nucleus was present. With a greater number of publications on this topic, revisiting this analysis is warranted. The aim of this meta-analysis was to systematically review and analyze the best clinical evidence regarding the association between the status of the ossific nucleus and development of osteonecrosis following the treatment of DDH.

METHODS

MEDLINE, Embase, and Cochrane databases were systematically searched for studies including the status of the ossific nucleus and rate of osteonecrosis after open and closed reductions for the treatment of DDH. Study characteristics and risk estimates were extracted. Study quality was assessed using the Newcastle-Ottawa Scale. Pooled effect estimates were calculated using a random-effect model. Meta-regression assessed the relationships of reduction method, study quality, mean age at reduction, surgical approach, method of ossific nucleus assessment, and duration of follow-up to the odds of osteonecrosis.

RESULTS

In the 21 observational studies (18 retrospective, 3 prospective) that were included, osteonecrosis developed in 20.4% of the hips in which the ossific nucleus was present at reduction compared with 21.2% of the hips in which the ossific nucleus was absent. Presence of the ossific nucleus was not associated with decreased odds of any grade of osteonecrosis (odds ratio [OR] = 0.70, 95% confidence interval [CI] = 0.43 to 1.12) or of more severe osteonecrosis of Grades II to IV (OR = 0.70, 95% CI = 0.30 to 1.17). Meta-regression did not show any effect of the mean age at reduction, reduction method, surgical approach, study quality, minimum or mean duration of follow-up, method of ossific nucleus imaging, or osteonecrosis classification system on the relationship between presence of the ossific nucleus and the risk of osteonecrosis.

CONCLUSIONS

The current literature does not support the hypothesis that presence of the ossific nucleus at reduction is associated with lower risk of osteonecrosis. Prospective studies with long-term follow-up and blinded assessors are warranted to optimally evaluate the relationship between potential risk factors and the development of osteonecrosis.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Association between the ossific nucleus and osteonecrosis in treating developmental dysplasia of the Hip: updated meta-analysis

Background

A meta-analysis concluded that there was no effect of the femoral head ossification and the incidence of osteonecrosis in the treatment of developmental dysplasia of the hip (DDH), unless only osteonecrosis grades II-IV were considered. The meta-analysis, limited due to the small number of studies available at that time, identified a need for an update as further research emerges. We observed a trend in recent years towards delaying treatment of DDH in the absence of an ossified nucleus. Numerous new publications on this topic encouraged us to update the 2009 meta-analysis.

Methods

We performed a systematic review of the literature from 1967 to 2016 and included studies that reported on the treatment of DDH, the ossific nucleus and osteonecrosis. Two independent reviewers evaluated all articles. We performed a meta-analysis with the main outcome defined as the development of osteonecrosis of the femoral head at least two years after closed or open reduction.

Results

Of four prospective and ten retrospective studies included in the systematic review, 11 studies (1,021 hips) met the inclusion criteria for the meta-analysis. There was no significant effect of the ossific nucleus on the development of all grades of osteonecrosis (relative risk, 0.88; 95% confidence interval, 0.56–1.41) or osteonecrosis grades II–IV (0.67; 0.41–1.08). In closed reductions, the ossific nucleus halved the risk for developing osteonecrosis grades II–IV (0.50; 0.26–0.94).

Conclusions

Based on current evidence there does not appear to be a protective effect of the ossific nucleus on the development of osteonecrosis. In contrast to the previous meta-analysis, this update demonstrates that this remains the case irrespective of the grade of osteonecrosis considered relevant. This updated meta-analysis is based on twice as many studies with a higher quality of evidence.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1468-6) contains supplementary material, which is available to authorized users.

Surgical Management of Pediatric Developmental Dysplasia of the Hip

In pediatric patients with developmental dysplasia of the hip with late presentation or failure of nonsurgical treatment, surgical management is indicated. The goal of surgery is to obtain a stable reduction to promote development of the femoral head and acetabulum while avoiding osteonecrosis of the femoral head and the need for further surgery. Treatment is related to the age of the patient and the degree of soft-tissue contracture or bony deformity present. As a general rule, in children aged <12 months, closed reduction and spica casting is preferred. Children aged 12 to 18 months may require open reduction, which can be performed safely through a medial or anterior approach. In children aged 18 months to 3 years, residual bony deformity can be corrected with a femoral or pelvic osteotomy in addition to open reduction. In children with complex deformity or in children aged >3 years, both pelvic and femoral osteotomies are commonly required to stabilize an open reduction.

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.

Does Perfusion MRI After Closed Reduction of Developmental Dysplasia of the Hip Reduce the Incidence of Avascular Necrosis?

BACKGROUND

Gadolinium-enhanced perfusion MRI (pMRI) after closed reduction/spica casting for developmental dysplasia of the hip (DDH) has been suggested as a potential means to identify and avoid avascular necrosis (AVN). To date, however, no study has evaluated the effectiveness of pMRI in clinical practice or compared it with other approaches (such as postreduction CT scan) to show a difference in the proportion of AVN.

QUESTIONS/PURPOSES

(1) Can a pMRI-based protocol be used immediately post closed reduction to minimize the risk that AVN would develop? (2) What are the overall hip-related outcomes after closed reduction/spica casting using this protocol? (3) Do any patient-specific factors at the time of closed reduction predict future AVN?

METHODS

This was a retrospective cohort study at a large tertiary care children's hospital. Between 2009 and 2013 we treated 43 patients with closed reduction/spica casting for DDH, of whom 33 (77%) received a postreduction pMRI. All patients were indicated for pMRI per treating surgeon preference. A convenience sample totaling 25 hips in 22 patients treated with pMRI was then established using the following exclusion criteria: DDH of neuromuscular/syndromic origin, failed initial closed reduction, less than 1 year of clinical and radiographic followup, and subsequent open reduction. Next, the 40 patients treated with closed reduction between 2004 and 2009 were screened until the chronologically most recent 25 hips (after applying the previously mentioned exclusion criteria) were identified in 21 of the first 34 patients (62%) screened. Although termed the CT group, specific postreduction imaging was not a defined inclusion criterion in this group with the majority (21 of 25 [84%]) receiving postreduction CT and the remainder (four of 25 [16%]) receiving only postreduction radiographs. All hips with globally decreased femoral head perfusion on postreduction pMRI were treated with immediate cast removal followed by repeat closed reduction or open reduction, as per surgeon preference, with two of 33 (6%) requiring such further interventions. Salter criteria were then used to determine the proportion of AVN on radiographs at 1-year and final followup. Secondary outcomes including residual dysplasia and the need for further corrective surgery were ascertained through radiographic and retrospective chart review.

RESULTS

At 1-year followup there was no difference in the proportion of AVN in the historical CT group as compared with the pMRI group (six of 25 [24%] versus one of 25 [4%]; odds ratio [OR], 7.6; 95% confidence interval [CI], 0.8-363; p = 0.098). However, by final followup there was a statistically higher proportion of AVN in the CT group (seven of 25 [28%] versus one of 25 [4%]; OR, 9.3; 95% CI, 1.0-438; p = 0.049). No patient with normal perfusion on postreduction pMRI went on to develop AVN. In those pMRI patients in whom a successful reduction was initially obtained, two of 25 (8%) went on to require further corrective surgery and one of 25 (4%) had a redislocation event. With the numbers available, no patient-specific factors at the time of closed reduction were predictive of future AVN, including the patient's age/weight, the presence of an ossific nucleus, history of previous bracing treatment, or the abduction angle in spica cast.

CONCLUSIONS

A pMRI-based protocol immediately after closed reduction/spica casting may decrease the risk of AVN by helping the surgeon to evaluate femoral head vascularity. Although preliminary in nature, this study could serve to guide further investigation into the potential role of pMRI for the treatment of patients who require closed reduction/spica casting for DDH.

LEVEL OF EVIDENCE

Level III, therapeutic study.

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.

Evidence-based management of developmental dysplasia of the hip

Developmental Dysplasia of the Hip (DDH) refers to a spectrum of abnormalities involving the developing hip. These abnormalities range from mild instability to frank dislocation of the joint. It is important to treat the condition effectively in order to encourage the hip to develop normally and produce good long-term results. This article reviews the evidence related to the treatment of DDH. The quality of evidence for DDH management remains low, with little uniformity in terminology and most studies being retrospective in nature. Given this, it is not possible to recommend or reject most treatment modalities based on existing studies.

Correlation between avascular necrosis and the presence of the ossific nucleus when treating developmental dysplasia of the hip

PURPOSE

This study assessed whether avascular necrosis (AVN) is correlated with the presence or absence of the ossific nucleus (ON) at the initiation of conservative treatment for developmental dysplasia of the hip (DDH). To date, the correlation between the presence of the ON and AVN manifestations remains ambiguous.

METHODS

The medical records of 148 patients with 234 dislocated hips who presented at our institution between January 2006 and December 2007 were reviewed. Based on ultrasound examination, the hips were classified according to Graf IIIa, IIIb, and IV criteria. Patients aged >6 months were simultaneously examined by standardized pelvis radiography.

RESULTS

The ON was present in 84 hips (35.9 %) at the beginning of treatment. Treatment was begun at a mean age of 5 months, with overhead traction for 2 weeks followed by arthrography and a spica cast for 4 weeks. Afterwards, we used a Tübingen hip-flexion splint. The mean age at final follow-up was 87 months. Hips were radiographically evaluated at last follow-up according to the Ogden-Bucholz AVN classification scheme. There was no significant difference in AVN prevalence between ON(-) versus ON(+) hips in children aged ≤10 months (P = 0.681), whereas when all age groups were analyzed together, AVN was significantly increased in ON(+) hips (P = 0.002). Clinical examination revealed no differences in limping, leg length inequality, and range of motion of hips in the ON(-) versus ON(+) groups.

CONCLUSION

We conclude that DDH treatment should be performed early without regard to the presence or absence of the ON. Reduction should not be delayed beyond >10 months of age because any delay in treatment increases the incidence of AVN.

Treatment of developmental dislocation of hip: does changing the hip abduction angle in the hip spica affect the rate of avascular necrosis of the femoral head?

Avascular necrosis (AVN) of the femoral head is a serious complication in the management of developmental dislocation of the hip. Increasing the abduction angle increases its stability but compromises the vascularity of the femoral head. From our database of 240 children treated for developmental dislocation of hip by the two senior authors between 1998 and 2008, we defined two groups of children who underwent closed or medial open reduction of the hip after a failed Pavlik treatment or if patients presented late. In group 1, the reduced hip was immobilized in around 90° flexion, 60° abduction, and 0-10° internal rotation. In group 2 the hip was immobilized in around 45° of hip abduction with flexion and internal rotation as before. The first and second authors independently analysed these two groups blinded to the hip abduction angle. Our hypothesis was that a reduction in the hip abduction angle would reduce the incidence of AVN in the second group without compromising the stability. All eligible children were included, and there were 42 children in group 1 and 44 children in group 2. An almost equal number of children underwent closed and medial open reduction in both the groups. The age at reduction was a mode of 6 months (range 6-13 months) and 7 months (range 7-12 months), respectively. The abduction angle in the first group had a mode of 60° (range 52-70°) and the second group had a mode of 45° (range 38-50°). Radiographic evidence of AVN as described by Salter and colleagues was seen in eight children (19%) in the first group and seven children (16%) in the second group (P=0.78). Redislocation occurred in one child in the second group and none in the first group. In summary, the results show a nonsignificant reduction in the incidence of AVN when the hip abduction angle was reduced with no significant increased risk of redislocation.

Developmental dysplasia of the hip: controversies and current concepts

Developmental dysplasia of the hip is an important but poorly understood disorder as evidenced by the vast amount of literature published to date on this topic. The precise definition of hip dysplasia is controversial and it encompasses a spectrum of abnormalities, rather than a single condition, which at one end overlap with normal hip maturation. We review the risk factors, clinical examination and radiological imaging of the hip in the infant and young child, the controversies of ultrasound screening for hip dysplasia and the current management, both operative and non-operative, of this condition according to patient age.

Strategies to improve nonoperative childhood management

Early diagnosis is of paramount importance to favorably alter the natural history of DDH. Most cases of dysplasia can be diagnosed by careful history taking and physical examination. Imaging modalities, such as ultrasonography, have increased our ability to detect subtleties not appreciated by means of physical examination or plain radiography. Although the evaluation of children with risk factors for DDH is important, most dysplasia occurs in girls who have no other risk factors. For all infants, a competent newborn physical examination using the Ortolani maneuver is the most useful procedure to detect hip instability. Early treatment of an unstable hip with a Pavlik harness or similarly effective orthosis is effective, safe, and strongly advised.

Osteonecrosis and femoro-acetabular impingement: sequelae of developmental dysplasia of the hip

A 2-year-old girl with developmental dysplasia of the right hip underwent open reduction and capsulorrhaphy via the anterior approach with hip spica casting in an internally rotated position. During her 26 years of follow-up, she was found to have osteonecrosis and subsequently cam-type femoro-acetabular impingement at 28 years of age. She was treated with surgical dislocation of the hip and osteochondroplasty to recreate the normal contour of the head and neck offset.

Does open reduction of the developmental dislocated hip increase the risk of osteonecrosis?

BACKGROUND

Osteonecrosis (ON) of the femoral head is one of the main complications associated with treatment of developmental dysplasia of the hips (DDH). The reported rates of ON vary widely between 6% and 48%, suggesting varying factors in these studies influence the rate. Several studies suggest open reduction combined with femoral shortening provides protection against ON. However, it is unclear whether confounders such as failed Pavlik harness treatment, preliminary traction, closed versus open reduction, and redislocation influence the rate of ON.

QUESTIONS/PURPOSE

We therefore asked whether open reduction with concomitant osteotomies without femoral shortening, redislocation, and secondary surgical procedures for residual acetabular dysplasia influenced the rate of ON.

METHODS

We retrospectively reviewed 64 children (78 hips) hospitalized with developmental dislocation of the hip between January 1998 and February 2007. Patients younger than 12 months were treated with closed or open reduction. Open reduction combined with concomitant pelvic and femoral osteotomies was performed in patients past walking age. ON was diagnosed from radiographs obtained at last followup. We used logistic regression analysis to identify predictors for the development of ON. The minimum followup was 3.2 years (mean, 6.8 years; range, 3.2-11.5 years).

RESULTS

The overall rate of ON was 40%. Patients who underwent open reduction combined with concomitant osteotomies, experienced redislocation, or required secondary reconstructive procedures after initial reduction were at higher risk for having ON develop.

CONCLUSIONS

We advocate early reduction of the dislocated hip in the first year of life to avoid the need for concomitant osteotomies combined with open reduction.

The presence of an ossific nucleus does not protect against osteonecrosis after treatment of developmental dysplasia of the hip

BACKGROUND

Osteonecrosis (ON) is a major complication after treatment of developmental dysplasia of the hip (DDH). Several studies have explored the absence of the femoral head ossific nucleus at the time of hip reduction as a risk factor for the development of ON, but findings have been inconsistent.

QUESTIONS/PURPOSES

We therefore determined the incidence of ON in children who underwent reduction of a dislocated hip in the presence or absence of the ossific nucleus.

PATIENTS AND METHODS

We retrospectively reviewed the radiographs of 105 hips in 89 patients treated for DDH at the age of 18 months or younger. Radiographs were graded for the presence of the ossific nucleus at the time of hip reduction and for the presence of ON, as graded by the Bucholz and Ogden classification, for patients at a mean age of 10 years. We used log-binomial regression to estimate if the presence of the ossific nucleus was associated with a lower incidence of ON.

RESULTS

We identified ON in 37 of the 105 hips (35%). The incidence of ON at 10 years was 40% in the absence of the ossific nucleus and 32% in the presence of the ossific nucleus (adjusted relative risk, 0.86; 95% confidence interval, 0.36-1.81). When only radiographic changes of Grade II and greater were considered ON, the risk was still not increased (relative risk, 1.26; 95% confidence interval, 0.62-2.56).

CONCLUSION

Patients with an ossific nucleus at the time of hip reduction showed a slight tendency toward better outcomes. The ossific nucleus did not protect for ON.

LEVEL OF EVIDENCE

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

Late reduction in congenital dislocation of the hip and the need for secondary surgery: radiologic predictors and confounding variables

BACKGROUND

Despite early recognition and appropriate treatment of congenital dislocation of the hip, there are a number of cases that subsequently require further surgery to prevent progressive dysplasia, instability, and eventual early osteoarthritis. This study aimed (1) to determine the incidence of pelvic osteotomy (PO) after late open (OR) or closed (CR) reduction for failed initial conservative treatment or late presentation; (2) study potential radiologic predictors of those that will require a secondary procedure; (3) and to evaluate the effect of potential confounding variables including age of reduction, Pavlik harness treatment, and surgical experience on PO rate.

METHODS

All cases of congenital dislocation of the hip that presented late or had failed conservative treatment with subsequent late OR versus CR, that were carried out during 1988 to 2003, by the lead surgeon were included. Dislocations secondary to neuromuscular causes or teratologic causes were excluded. Intraoperative arthrograms confirmed the concentric or eccentric reduction and determined subsequent intervention. The AP pelvis plain radiograph was used to measure the height of dislocation, as described by Tonnis, and monitor Acetabular index, and ossific nucleus width and height postreduction.

RESULTS

After 134 OR's, 24 hips (19%, 95% CI: 16-23%) later required a pelvic osteotomy compared with 59 out of 104 hips (58%, 95% CI: 49-68%) in the CR cohort. There was no statistical difference in avascular necrosis rates between late OR (10.9%, 95% CI: 4.8-17%) and CR (11.4%, 95% CI: 5.8-17%). Acetabular index was a reliable predictor for the need of subsequent PO becoming significantly different in those that did (PO group) and did not (non-PO group) require further surgery approximately 1.5 years postreduction. There was no difference in the ON development after reduction in both PO and non-PO groups. The PO requirement was not affected by earlier failed Pavlik harness treatment but did change with ongoing surgical experience. Late OR produced the lowest secondary procedure rate without an increase in the incidence of avascular necrosis. There is a learning curve to this procedure that will affect these outcomes.

LEVEL OF EVIDENCE

Level III (Case-control study).

The effect of the femoral head ossific nucleus in the treatment of developmental dysplasia of the hip. A meta-analysis

BACKGROUND

The role of the presence of the femoral head ossific nucleus as a risk factor for the development of osteonecrosis of the femoral head in infants with developmental dysplasia of the hip has been investigated in several small studies, but the results have been inconsistent. The purpose of the present study was to determine the effect of the presence of the ossific nucleus on the development of osteonecrosis.

METHODS

A systematic review of the medical literature from 1966 to 2007 was performed. Two independent reviewers evaluated all articles. Interrater agreement was determined, and the quality of evidence was evaluated. A meta-analysis was then performed with the main outcome defined as the development of osteonecrosis of the femoral head two years after reduction.

RESULTS

Six observational studies (five retrospective and one prospective) met the inclusion criteria. Inconsistency was found in that half of the studies demonstrated a protective effect of the ossific nucleus on the development of osteonecrosis whereas half of the studies did not. A meta-analysis (including 358 patients) showed no significant effect of the presence of the ossific nucleus on the development of grades-I through IV osteonecrosis, with forty-one cases of osteonecrosis (19%) found in infants in whom the ossific nucleus had been present at the time of hip reduction compared with thirty cases (22%) in the group without an ossific nucleus (relative risk=0.75, 95% confidence interval=0.46 to 1.21). When only radiographic changes of grade II or worse were considered to represent osteonecrosis, a significant difference in the prevalence of osteonecrosis was found, with fourteen cases of osteonecrosis (7%) in infants with an ossific nucleus compared with eighteen cases (16%) in those without an ossific nucleus (relative risk=0.43, 95% confidence interval=0.20 to 0.90). A subgroup analysis showed that the presence of the ossific nucleus reduced the probability of osteonecrosis by 60% (relative risk=0.41, 95% confidence interval=0.18 to 0.91) after closed reduction, but no significant effect was found in patients treated with open reduction (relative risk=1.14, 95% confidence interval=0.62 to 2.07). All studies demonstrated methodological weaknesses compromising the quality of evidence.

CONCLUSIONS

We did not find that the presence of the ossific nucleus had a significant effect on the development of osteonecrosis of any grade after hip reduction in infants with developmental dysplasia of the hip. The meta-analysis suggested that the presence of the ossific nucleus has a protective effect against the development of the more severe forms of femoral head osteonecrosis. However, the quality of evidence is moderate, and additional research is likely to have an important impact on the confidence in the estimate of the effect and may change this estimate.

Post-closed reduction perfusion magnetic resonance imaging as a predictor of avascular necrosis in developmental hip dysplasia: a preliminary report

INTRODUCTION

Avascular necrosis (AVN) of the femoral head remains a major complication in the treatment of developmental dysplasia of the hip (DDH) in infants. We performed a retrospective analysis to look at the predictive ability of postclosed reduction contrast-enhanced magnetic resonance imaging (MRI) for AVN after closed reduction in DDH.

METHODS

Twenty-eight hips in 27 infants (aged 1-11 months) with idiopathic hip dislocations who had failed brace treatment underwent closed reduction +/- adductor tenotomy and spica cast application under general anesthesia. Magnetic resonance imaging of the hips after intravenous gadolinium contrast injection for evaluation of epiphyseal perfusion was obtained immediately after cast application. Patients were followed with serial radiographs for a minimum of 1 year after closed reduction. Presence of AVN was determined by the presence of any one of the 5 Salter criteria by 2 readers. Magnetic resonance imaging was graded as normal, asymmetric enhancement, focal decreased enhancement, or global decreased enhancement by 2 radiologists.

RESULTS

Six (21%) of 28 hips showed evidence of clinically significant AVN on follow-up radiographs. Fifty percent of the hips with AVN, but only 2 of 22 hips without AVN, showed a global decreased MRI enhancement (P < 0.05, Fisher exact test). Multivariate logistic regression indicated that a global decreased enhancement was associated with a significantly higher risk of developing AVN (P < 0.01), independently of age at reduction (P = 0.02) and abduction angle.

CONCLUSIONS

In addition to accurate anatomical assessment of a closed reduction in DDH, gadolinium-enhanced MRI provides information about femoral head perfusion that may be predictive for future AVN. At present, it is premature to use the perfusion information for routine clinical use. However, it opens the door to studies looking at repositioning or alternative reduction methods that may reduce the risk of AVN in this higher risk group.

Avascular necrosis rate in early reduction after failed Pavlik harness treatment of developmental dysplasia of the hip

Our hypothesis is that hips with developmental dysplasia (DDH), which fail Pavlik harness treatment and are reduced within 3 months of age, have a low rate of avascular necrosis (AVN). Inclusion criteria are as follows: diagnosis of DDH within 2 months of birth, failure of reduction or stabilization by Pavlik harness treatment, surgical reduction of the hip advised to be performed within 3 months of age, and follow-up for Salter criteria of AVN. Twenty-one consecutive cases (35 hips) met the inclusion criteria. Nineteen cases (31 hips) were initially reduced within 3 months of age, and none of these cases developed AVN. After Pavlik harness failure, initial closed reduction was achieved in 33 (94%) of 35 hips, and open reduction required in 2 (6%) of 35 hips. At latest follow-up, one (3%) of 35 hips had AVN. At the time of reporting, 1 (3%) of the 35 hips has required an additional procedure (Pemberton osteotomy) for residual dysplasia. There were 2 outlier cases (4 hips) in which the parents delayed the reduction and 1 case developed unilateral AVN, which was reduced after the proximal femoral ossification center developed at 7 months of age. The data presented in the current study support our hypothesis.

The role of the ossific nucleus in the treatment of established hip dislocation

Timing the reduction of a delayed presenting dislocated hip is controversial if the ossific nucleus of the proximal femoral epiphysis is absent. We formulated a decision model for management of 6- to 13-month-old infants based on two strategies: waiting for the ossific nucleus to appear before reducing the hip or immediate reduction. The model included the occurrence of long-term physical disability within a period of 20 years. A literature synthesis provided outcome probabilities. Outcome was measured by utilities derived by content experts. Waiting for the ossific nucleus was the preferred strategy with an expected value of 0.95 as opposed to 0.86 in the immediate reduction strategy. Sensitivity analyses showed the model was robust. Based on the results of decision analysis, reducing a dislocated hip in the presence of the ossific nucleus is likely to be the better strategy if avascular necrosis and long-term disability are considered. The difference between the two strategies is equivalent to one quality-adjusted life year, which is substantial.

LEVEL OF EVIDENCE

Economic and Decision Analyses, Level II-1. See the Guidelines for Authors for a complete description of levels of evidence.

Simultaneous open reduction and Dega transiliac osteotomy for developmental dislocation of the hip in children under 24 months of age

The authors studied retrospectively 33 hips in 26 children at an average of 9 years 5 months after simultaneous open reduction and Dega transiliac osteotomy for developmental dislocation of the hip (DDH). All children were younger than 2 years of life at surgery. At the latest follow-up 89% of the clinical results and 72% of the radiographic results were rated excellent or good, despite a 45% rate of avascular necrosis observed before surgery. The authors attempted to identify factors influencing the final result. Given the low complication rate (3%) and low reoperation rate (3%), the authors conclude that the reviewed surgical protocol is safe and efficient in the treatment of DDH in young children.

The surgical treatment of established congenital dislocation of the hip: results of surgery after planned delayed intervention following the appearance of the capital femoral ossific nucleus

It has been proposed that the presence of the capital femoral ossific nucleus confers protection against ischemic injury or avascular necrosis (AVN) at the time of reduction of a congenitally dislocated hip. The current literature is contradictory. A prospective study was undertaken of the clinical and radiologic outcomes following closed or open reduction. Fifty hips were included in the study. These cases had presented late or had failed conservative treatment. In 28 hips treatment was intentionally delayed until the appearance of the ossific nucleus (but not beyond 13 months) and in 22 the ossific nucleus was present at clinical presentation. Six hips reached the age of 13 months without an ossific nucleus appearing and progressed to treatment. The significant AVN rate (more than grade 1) was 7% for closed reduction and 14% for open. However, the amended rate if hips were excluded that had failed Pavlik harness treatment was 0.0% and 9%, respectively (4% overall). Further surgical procedures were necessary in 57% of hips undergoing closed reduction and 41% after open, which compares favorably with other series. The authors conclude that the presence of the ossific nucleus is an important factor in the prevention of AVN, particularly after late closed reduction. Intentional delay in the timing of surgery does not condemn a hip to open surgery, but there is a comparable rate of secondary procedures becoming necessary, particularly after closed reduction. A simultaneous pelvic procedure may be appropriate after late closed reduction. The delayed strategy to await the appearance of the ossific nucleus for previously untreated dislocation allows a simple treatment algorithm to be employed that produces good clinical and radiologic outcomes.

Open reduction through a medial approach in developmental dislocation of the hip: a follow-up study to skeletal maturity

Forty-four developmentally dislocated hips occurring in 30 patients with an average age at initial surgery of 10.7 (range 2-19) months underwent medial open reduction by Ferguson's approach. All patients were skeletally mature at most recent evaluation. Mean follow-up was 19.8 (range 13-27.5) years. No redislocation or sub-luxation occurred. Additional surgery was required in 11 hips (25%). Avascular necrosis was detected in nine hips (20%). The acetabular index was decreased and the center-edge angle was increased during follow-up. Excellent or good outcome (Severin group 1 or 2) was observed in 79% of the hips at skeletal maturity. At the most recent evaluation, all but two patients had the highest score on the Iowa Hip Rating. The authors conclude that open reduction through the medial approach is effective in developmental dislocation of the hip. Follow-up until skeletal maturity is necessary for an accurate assessment of treatment.

Reduction of a dislocation of the hip due to developmental dysplasia. Implications for the need for future surgery

BACKGROUND

Recent reports on the treatment of a dislocation of the hip due to developmental dysplasia have documented conflicting data on the importance of the ossific nucleus in the development of postreduction ischemic necrosis. Delaying reduction until the ossific nucleus is present bypasses the time-period of maximal osseous remodeling of the hip, thereby possibly increasing the need for future operations. We hypothesized that hips with an ossific nucleus are more likely to have subsequent reconstructive procedures.

METHODS

A retrospective review of the medical records at two tertiary-care children's hospitals was completed to identify all patients who had had reduction of a dislocation of the hip due to developmental dysplasia, performed between 1979 and 1993, when they were less than two years old. Patients were excluded if the medical records or radiographs were inadequate, the duration of follow-up was less than three years after the final reduction, a previous reduction had been performed at an outside facility, or the patient had a neuromuscular disease or a teratologic dislocation. We identified 124 patients (153 hips) who satisfied the criteria for inclusion. The average age at the time of the reduction was eleven months, and the average duration of follow-up was 7.2 years.

RESULTS

Overall, fourteen of the sixty-three hips without an ossific nucleus had a reconstructive procedure: thirteen had a varus rotational osteotomy of the proximal part of the femur and one had a combined pelvic and varus rotational femoral osteotomy. Forty of the ninety hips with an ossific nucleus had a reconstructive procedure: twenty-seven had a varus rotational osteotomy, eight had a pelvic osteotomy, and five had a combined pelvic and varus rotational osteotomy (p < 0.05). In addition, secondary reconstructive procedures were performed in 17% (ten) of the fifty-nine patients who were less than six months old and in 35% (thirty-three) of the ninety-four patients who were at least six months old, which was a greater than twofold increase. The effect of age was further emphasized at the other age cutoff points.

CONCLUSION

Delaying the reduction of a dislocated hip until the appearance of the ossific nucleus more than doubles the need for future surgery to make the hip as anatomically normal as possible. Despite finding a slight increase in the rate of ischemic necrosis after reduction of the hips without an ossific nucleus, we advocate early reduction of a dislocation of a hip due to developmental dysplasia to optimize the development of the hip with the minimum number of operations

Evaluation of the risk factors of avascular necrosis of the femoral head in developmental dysplasia of the hip in infants younger than 18 months of age

Sixty-seven dysplastic hips of 54 infants with an average age of 11.9 months were treated by the same surgical technique, including iliopsoas and adductor tenotomies via medial approach and arthrography for verification of the concentric reduction. The average follow-up period was 44.5 months. The rate of overall avascular necrosis (AVN) was 27% and that of severe AVN was 7%. With the numbers available in the study, a statistically significant relationship could not be found between the rate and severity of AVN and several preoperative and intraoperative components such as age, sex, side, dislocation grade, development of the ossific nucleus and qualitv of intraoperative reduction. Nevertheless, hips of infants treated between 13 months and 15 months of age, hips of male patients and left hips had slightly higher ratios of ischemic changes that were not statistically significant.