Avascular necrosis after open reduction for congenital dislocation of the hip: analysis of causative factors and natural history

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.

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.

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.

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

Background

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

Methods

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

Results

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

Conclusion

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

A Comparative Study of Clinical and Radiological Outcomes of Open Reduction Using the Anterior and Medial Approaches for the Management of Developmental Dysplasia of the Hip

BACKGROUND

The literature is scanty on reports directly comparing the outcomes of anterior open reduction (AOR) and medial open reduction (MOR) in the management of developmental dysplasia of the hip (DDH).

PURPOSE OF THE STUDY

To compare clinical and radiographic outcomes of surgical treatment using either AOR or MOR in children with DDH aged < 24 months and to evaluate the procedure-inherent risks of avascular necrosis of the femoral head (AVN) and need for further corrective surgery (FCS).

METHODS

61 children who underwent surgical treatment for DDH were categorized into two groups: AOR (31 hips of 28 patients) and MOR (39 hips of 33 patients). The mean age was 17 ± 5.85 (range 7-24) months in group AOR and 13 ± 5.31 (range 6-24) months in group MOR. The mean follow-up was 118 ± 41.2 (range 24-192) months and 132 ± 36.7 (range 24-209) months in group AOR and MOR. At the final follow-up, mid- to long-term clinical and radiographic outcomes were assessed. FCS was recorded.

RESULTS

Regarding McKay's clinical criteria, both groups exhibited similar results (p = 0.761). No significant differences were observed between the groups in both the center-edge-angle (p = 0.112) and the Severin score (p = 0.275). The AVN rate was 32% in the AOR group and 20% in the MOR group (p = 0.264). The FCS rate was 22% in the AOR group and 12% in the MOR group (p = 0.464).

CONCLUSIONS

This study showed similar clinical and radiological outcomes with AOR and MOR with no significant relation to AVN and FCS.

LEVEL OF EVIDENCE

Level III.

Salter osteotomy without open reduction in the Tönnis type II developmental hip dysplasia: A retrospective clinical study

PURPOSE

We aimed to evaluate the clinical and radiological outcomes of children older than 18 months who were treated with Salter osteotomy without open reduction for Tönnis type II hip dysplasia.

METHODS

Thirty-two type II hips of 24 patients were included in the study. The mean age was 43.22 (18-108) months. The mean follow-up period was 50 (24-142) months. Seven patients had left sided, nine had right sided, and eight had bilateral developmental dysplasia of the hip. All patients underwent closed reduction and Salter osteotomy. Preoperative and postoperative radiographs were assessed by measuring the center-edge (CE) angle of Wiberg, Smith's c/b and h/b ratio, and acetabular index (AI). Patients were evaluated clinically according to McKay's criteria and radiologically according to Severin criteria. The Kalamchi and MacEwen criteria were used in the evaluation of avascular necrosis.

RESULTS

The mean preoperative AI, CE angle, c/b, and h/b ratio were 36.7° (±4.1), 7.2° (±5.9), 0.9 (±0.08), and 0.05 (±0.04), respectively. The mean latest follow-up AI, CE angle, c/b, and h/b ratio were 18.2° (±1.7), 38.8° (±5.4), 0.6 (±0.03), and 0.19 (±0.04), respectively. The comparison of preoperative and postoperative radiological values revealed statistically significant improvement ( p < 0.01). On the latest physical examinations of the patients, 25 (78.1%) hips were rated excellent, and 7 (21.9%) were rated good according to the McKay criteria. The Severin classification determined 25 (78.1%) hips were grade I and 7 (21.9%) hips were grade II. Type I avascular necrosis (AVN) was seen in four (12.5%) hips. Three of these four hips were more superolateral in preoperative radiographs (c/b > 1 and h/b < 0.05).

CONCLUSIONS

Salter osteotomy without open reduction is a good surgery option for Tönnis type II hip dysplasia, in which closed reduction can be performed. However, the risk of AVN should be kept in mind in more superolateral type 2 hips.

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.

Effect of abduction on avascular necrosis of the femoral epiphysis in patients with late-detected developmental dysplasia of the hip treated by closed reduction: a MRI study of 59 hips

PURPOSE

The purpose of this study was to explore whether increasing the hip abduction angle would increase the incidence of avascular necrosis (AVN) in patients with late- detected developmental dysplasia of the hip (DDH) treated by closed reduction (CR) and spica cast immobilization.

METHODS

A total of 55 patients (59 hips) with late-detected DDH underwent MRI after CR. Hip abduction angle and hip joint distance were measured on postoperative MRI transverse sections. The acetabular index and centre-edge angle were measured on plain radiographs at the last follow-up. The presence of AVN according to Kalamchi and McEwen's classification was assessed. We retrospectively analyzed the associations among abduction angles, hip joint distances, radiographic parameters, AVN and final outcomes, exploring the relationship between hip joint abduction angle and AVN rate.

RESULTS

The mean age at the time of CR was 14.4 months SD 5.5 (6 to 28), and the mean follow-up was 26.2 months SD 8.1 (12.4 to 41.7). The mean hip abduction angle was 70.2° SD 7.2° (53° to 85°) on the dislocated side and 63.7° SD 8.8° (40° to 82°) on the normal side; the mean hip joint distance was 5.1 mm SD 1.9 (1.3 to 9.1) on the dislocated side and 2.2 mm SD 0.6 on the normal side (1.3 to 3.3). Eight of 59 hips (13.6%) developed AVN. Neither the amount of abduction nor hip joint distance increased the AVN rate (p = 0.97 and p = 0.65, respectively) or the dislocation rate (p = 0.38 and p = 0.14, respectively).

CONCLUSION

Abduction angle up to 70.2° following CR did not increase the AVN rate in children aged six to 28 months with late-detected DDH treated by CR.

LEVEL OF EVIDENCE

III.

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.

Patchy increased echogenicity: a sonographic sign of femoral head necrosis following reduction and casting for developmental dysplasia of the hip

A developmental dysplasia of the hip (DDH) case treated by closed reduction and casting and subsequently confirmed to have avascular necrosis (AVN) was retrospectively noted to have an abnormal pattern of echogenicity in the femoral head on sonograms obtained within 1.5 months of surgery. Patchy increased echogenicity in parts of the unossified cartilage replaced the normal pattern of central coalescence of vessels described with development of the ossification center. An additional case with similar findings confirms this should be considered a sign of evolving AVN following closed reduction.

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.

Avascular necrosis in children with cerebral palsy after reconstructive hip surgery

PURPOSE

Progressive hip displacement is one of the most common orthopaedic pathologies in children with cerebral palsy (CP). Reconstructive hip surgery has become the standard treatment of care. Reported avascular necrosis (AVN) rates for hip reconstructive surgery in these patients vary widely in the literature. The purpose of this study is to identify the frequency and associated risk factors of AVN for reconstructive hip procedures.

METHODS

A retrospective analysis was performed of 70 cases of reconstructive hip surgery in 47 children with CP, between 2009 and 2013. All 70 cases involved varus derotation osteotomy (VDRO), with 60% having combined VDRO and pelvic osteotomies (PO), and 21% requiring open reductions. Mean age at time of surgery was 8.82 years and 90% of patients were Gross Motor Function Classification System (GMFCS) 4 and 5. Radiographic dysplasia parameters were analysed at selected intervals, to a minimum of one year post-operatively. Severity of AVN was classified by Kruczynski's method. Bivar- iate statistical analysis was conducted using Chi-square test and Student's t-test.

RESULTS

There were 19 (27%) noted cases of AVN, all radio- graphically identifiable within the first post-operative year. The majority of AVN cases (63%) were mild to moderate in severity. Pre-operative migration percentage (MP) (p = 0.0009) and post-operative change in MP (p = 0.002) were the most significant predictors of AVN. Other risk factors were: GMFCS level (p = 0.031), post-operative change in NSA (p = 0.02) and concomitant adductor tenotomy (0.028).

CONCLUSION

AVN was observed in 27% of patients. Severity of displacement correlates directly with AVN risk and we suggest that hip reconstruction, specifically VDRO, be performed early in the 'hip at risk' group to avoid this complication.

Overhead Bryant's Traction Does Not Improve the Success of Closed Reduction or Limit AVN in Developmental Dysplasia of the Hip

BACKGROUND

Preoperative Bryant's overhead traction before closed reduction (CR) in developmental dysplasia of the hip (DDH) remains controversial and its success in increasing CR rates and reducing avascular necrosis (AVN) rates has not been specifically reported in a large cohort.

METHODS

IRB-approved retrospective study of patients (below 3 y)who were treated with attempted CR for idiopathic DDH from 1980 to 2009. Successful CR was defined as a hip that remained reduced and did not require repeat CR or open reduction. Patients were grouped by age, hip instability [Ortolani positive (reducible) vs. fixed dislocation], and Tonnis classification and rates of successful CR were compared between groups with P<0.05.

RESULTS

A total of 342 hips were included with a mean age of 0.9 years (0.2 to 2.8 y) and a mean follow-up of 10.4 years (2.0 to 27.7 y). There were 269 hips with fixed dislocations and 73 Ortolani-positive hips. Traction was used in 276 hips. There was no difference in traction utilization in the 3 age groups (below 1, below 1.5, and below 2 y) for either Ortolani-positive hips (P=0.947) or fixed dislocations (P=0.943). There was no difference in achieving a successful CR comparing traction (60.9%) and no-traction groups (60.6%) (P=1.00). For Ortolani-positive hips, traction did not improve the incidence of a successful CR for any age group: below 1 year: P=0.19; below 1.5 years: P=0.23; and below 2 years: P=0.25. Similarly, fixed dislocation patients had no benefit from traction: below 1 year: P=0.76; below 1.5 years: P=0.82; and below 2 years: P=0.85. Tonnis classification did predict success of CR but had no influence on traction success. There was no difference in the rate of AVN between the traction (18%) and no-traction (8%) groups for all patients (P=0.15).

CONCLUSIONS

In this retrospective series, preoperative Bryant's traction does not improve the rate of a successful CR for patients with DDH and has no protective effect on the development of AVN of the femoral head. These results suggest that Bryant's overhead traction may not be warranted for patients below 3 years of age with DDH.

LEVEL OF EVIDENCE

Level III.

Spica magnetic resonance imaging for determination of abduction angle: initial results and reproducibility assessment

PURPOSE

Spica magnectic resonance imaging (MRI) is an established technique for postoperative determination of hip reduction in patients treated for developmental dysplasia of the hip (DDH). A hip abduction angle >55° is considered excessive and has been associated with epiphyseal osteonecrosis. Our purpose was to establish objective criteria for measuring hip abduction angles on MRI after hip reduction and spica casting in patients with DDH, and evaluate reproducibility and reliability of angle measurement using these criteria.

METHODS

Forty patients with DDH at our institution who underwent spica MRI after hip reduction between 3 April 2008 and 3 March 2015 were identified. Hip abduction angles were measured on proton density axial images as follows. A transverse line was drawn connecting the posterior ischial tuberosities. A second line was drawn medially along the distal femoral diaphysis, and the angle between these two lines was measured; this value was subtracted from 90°, yielding the degree of abduction from midline. Measurements were independently performed by three faculty radiologists, one orthopedist, and one radiology resident. Inter-reader and intra-reader reliability was assessed using intraclass correlation (ICC), with 0 representing no agreement and 1 representing perfect agreement.

RESULTS

For inter-reader reliability, the ICC of the five physicians was 0.89 (95 % CI 0.84-0.92). For intra-reader reliability, the ICC of the five physicians ranged from 0.90-0.97 (95 % CI 0.85-0.98). The mean standard deviation of hip abduction angle measurement among readers was 3.6°.

CONCLUSION

The proposed hip abduction angle measurement criteria for spica MRI are both reproducible and easy to perform. The high ICC and low standard deviation of independently evaluated hip abduction angles indicates high reproducibility of measurement. This applies to both inter- and intra-reader reliability.

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.

Acetabuloplasties at Open Reduction Prevent Acetabular Dysplasia in Intentionally Delayed Developmental Dysplasia of the Hip: A Case-control Study

BACKGROUND

Avascular necrosis (AVN) and residual acetabular dysplasia are the two main complications of developmental dysplasia of the hip (DDH) treatment. Although early reduction of the hip may decrease the incidence of residual dysplasia, it may increase the incidence of AVN and vice versa. However, we do not know if changes in surgical technique may lead to a modification in these outcomes.

QUESTIONS/PURPOSES

Does an incomplete periacetabular acetabuloplasty, as an added step to delayed open reduction, (1) diminish the risk of developing acetabular dysplasia; or (2) increase the rate of AVN compared with patients treated with open reduction alone?

METHODS

We conducted a retrospective matched case-control study comparing 22 patients (27 hips) with early isolated DDH who underwent intentionally delayed open reduction and acetabuloplasty from 2004 to 2010 and followed up > 4 years (88% of the cohort) with early historic controls treated with delayed open reduction alone. Of 53 patients available for matching, 45 (85%) had enough followup (> 10 years) to be considered. They were matched one to one for age at presentation and bilaterality (fuzz 45, 0). This generated a control group of 25 patients (27 hips). The mean followup was different between the groups (p < 0.001). Residual dysplasia considered when center-edge angle < 15° (6-13 years old) or < 20° (≥ 14 years old) or as a nonevolving acetabular index > 30° and pelvic osteotomies were used as our primary outcomes. The proportion of patients with AVN was also compared.

RESULTS

Patients treated with open reduction and an incomplete periacetabular acetabuloplasty were less likely to develop acetabular dysplasia and undergo pelvic osteotomies than were patients in the control group (0% [zero of 27] versus 37% [10 of 27]; odds ratio [OR], 11; 95% confidence interval [CI], 2-80; p = 0.02 and 0% [zero of 27] versus 26% [seven of 27]; OR, 8; 95% CI, 1-60; p = 0.025, respectively). With the available numbers, there was no difference in terms of the proportion of patients who developed AVN (11 of 27 [41%] both groups; OR, 1; 95% CI, 1-2; p = 1).

CONCLUSIONS

The addition of an incomplete periacetabular acetabuloplasty to all hips undergoing open reduction eliminated residual acetabular dysplasia, whereas it did not appear to have deleterious effects as evidenced by the similar AVN proportion.

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.

Failed Pavlik harness treatment for DDH as a risk factor for avascular necrosis

BACKGROUND

Avascular necrosis (AVN) of the femoral head is an irreversible complication seen in the treatment of developmental dysplasia of hip (DDH) with the Pavlik harness. Its incidence is reported to be low after successful reduction of the hip but high if the hip is not concentrically relocated. We aim to investigate its incidence after failed Pavlik harness treatment.

METHODS

We prospectively followed up a group of children who failed Pavlik harness treatment for DDH treated at our institution by the senior author between 1988 and 2001 and compared their rates of AVN with a group of children who presented late and hence were treated surgically. AVN was graded as described by Kalamchi and MacEwen and only grade 2 to 4 AVN was considered significant and included in the analysis.

RESULTS

Thirty-seven hips were included in the failed Pavlik group (group 1) and 86 hips in the no Pavlik group (group 2). Ten hips in group 1 developed AVN (27%), whereas only 7 hips in group 2 (8%) developed AVN; the odds of developing AVN after failed Pavlik treatment was 4.7 (95% confidence interval, 1.3-14.1) (P=0.009) with a relative risk of 3.32 (range, 1.37 to 8.05).

CONCLUSIONS

There was no statistically significant association observed with duration of splintage and severity of AVN (Spearman's correlation, -0.46; P=0.18). However, there was a positive correlation noted with age at presentation and severity of AVN. Therefore, we advise close monitoring of hips in the Pavlik harness and discontinue its use if the hips are not reduced within 3 weeks.

LEVEL OF EVIDENCE

Level III.

Medial versus anterior open reduction for developmental hip dislocation in age-matched patients

BACKGROUND

The difference between medial (MAOR) and anterior (AAOR) approaches for open reduction of developmental hip dysplasia in terms of risk for avascular necrosis (AVN) and need for further corrective surgery (FCS, femoral and/or acetabular osteotomy) is unclear. This study compared age-matched cohorts undergoing either MAOR or AAOR in terms of these 2 primary outcomes. Prognostic impact of presence of ossific nucleus at time of open reduction was also investigated.

METHODS

Institutional review board approval was obtained. Nineteen hips (14 patients) managed by MAOR were matched with 19 hips (18 patients) managed by AAOR based on age at operation (mean 6.0; range, 1.4 to 14.9 mo). Patients with neuromuscular conditions and known connective tissue disorders were excluded. Primary outcomes assessed at minimum 2 years' follow-up included radiographic evidence of AVN (Kalamchi and MacEwen) or requiring FCS.

RESULTS

MAOR and AAOR cohorts were similar regarding age at open reduction, sex, laterality, and follow-up duration. One hip in each group had AVN before open reduction thus were excluded from AVN analysis. At minimum 2 years postoperatively (mean 6.2; range, 1.8 to 11.7 y), 4/18 (22%) MAOR and 5/18 (28%) AAOR met the same criteria for AVN (P=1.0). No predictors of AVN could be identified by regression analysis. Presence of an ossific nucleus preoperatively was not a protective factor from AVN (P=0.27). FCS was required in 4/19 (21%) MAOR and 7/19 (37%) AAOR hips (P=0.48). However, 7/12 (54%) hips failing closed reduction required FCS compared with 4/26 (16%) hips without prior failed closed reduction (P=0.024). Cox regression analysis showed that patients who failed closed reduction had an annual risk of requiring FCS approximately 6 times that of patients without a history of failed closed reduction (hazard ratio=6.1; 95% CI, 1.5-24.4; P=0.009), independent of surgical approach (P=0.55) or length of follow-up (P=0.78).

CONCLUSIONS

In this study of age-matched patients undergoing either MAOR or AAOR, we found no association between surgical approach and risk of AVN or FCS. In addition, we identified no protective benefit of a preoperative ossific nucleus in terms of development of AVN. However, failing closed reduction was associated with a 6-fold increased annual risk of requiring FCS.

SIGNIFICANCE

To the best of our knowledge, this is the first study comparing these 2 surgical techniques in an age-matched manner. It further corroborates previous studies stating that there may be no difference in risk of AVN based on surgical approach or presence of ossific nucleus preoperatively.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

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.

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.

Contoured iliac crest allograft interposition for pericapsular acetabuloplasty in developmental dislocation of the hip: technique and short-term results

BACKGROUND

Pericapsular acetabuloplasty procedures have been widely used as an integral component of combined surgery to treat developmental hip dislocation after walking age. The stability of the acetabuloplasty and the maintenance of the acetabular correction will depend on the structural integrity of the iliac crest autograft, which, traditionally, has been inserted as the interposition material. Problems related to the use of an autograft have been encountered by various surgeons-including the authors-namely, graft displacement and resorption, which may necessitate internal fixation or result in revision surgery. To overcome autograft failure, the use of an allograft as the interposition material has been introduced by some surgeons. This study describes the radiologic results of 147 hips treated for developmental hip dislocation by means of a standard protocol of open hip reduction and pericapsular acetabuloplasty with a contoured iliac crest allograft as the interposition material.

METHODS

This retrospective study reviewed the radiographs of 147 hips presenting with late developmental dislocation which were treated by open reduction and a concomitant pericapsular acetabuloplasty using a contoured iliac crest allograft as the interposition material. The minimum follow up period was 2 years. Measurement of the acetabular index (AI) was the main variable. The efficacy of the interposed iliac crest allograft as the main stabiliser of the acetabuloplasty was reflected by the maintenance of the corrected AI during the follow up period. Loss of acetabular correction, graft extrusion or resorption, the need for osteotomy internal fixation, delayed or non union, infection, hip redislocation and avascular necrosis (AVN) as possible complications were documented.

RESULTS

The treatment protocol of a combined open reduction of the hip and pericapsular acetabuloplasty, inserting a contoured iliac crest allograft as the interposition material, resulted in concentrically reduced and stable hips in 96.6% of our cases. The redislocation rate was 3.4%. All of the allografts were completely incorporated at 6 months post-surgery with no graft-related infections. In only two hips was the acetabular correction not maintained. None of the osteotomies required internal fixation for stability, even in older children.

CONCLUSION

We believe that a contoured iliac crest allograft as the pericapsular acetabuloplasty interposition material renders excellent osteotomy stability that eliminates the need for internal fixation and-in the short-term-maintains the correction of the acetabulum achieved intra-operatively.

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

BACKGROUND

Kalamchi and MacEwen (K&M) described a four-group scheme for classifying osteonecrosis (ON) following treatment for developmental dysplasia of the hip (DDH). However, the four groups can overlap in radiographic appearance, making assessment difficult.

QUESTIONS/PURPOSES

We (1) describe a simplified K&M classification; (2) determined whether the simplified classification was reliable; and (3) assessed whether differences in the type of reduction or age at reduction resulted in different degrees of ON.

PATIENTS AND METHODS

We retrospectively reviewed 300 patients with DDH treated with either open or closed reduction. We included 101 of these patients (133 involved hips). Intraobserver and interobserver reliability testing of the original and our simplified classification was performed. ON occurred in 64 hips (48%). Of these, 22 had original K&M Group I disease (classified as simplified Group A), and 42 had original K&M Groups II, III, or IV disease (classified as simplified Group B). The mean age of the patients at final followup was 12.4 years (range, 6-26.3 years).

RESULTS

The interobserver reliability of the simplified classification was greater than that of the K&M classification (0.51 vs 0.33, respectively). Closed reduction after skin traction resulted in a lower incidence of Group B ON than open reduction, regardless of age at reduction.

CONCLUSIONS

We propose a simplified and more reliable classification of ON after DDH. With the new classification we found type of reduction (closed with traction versus open without femoral shortening) but not age influenced the risk of ON.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

The height-to-width index for the assessment of femoral head deformity following osteonecrosis in the treatment of developmental dysplasia

BACKGROUND

The principal complications that follow the treatment of developmental dysplasia of the hip are redislocation and growth disturbance of the femoral head and neck as a result of osteonecrosis of the femoral epiphysis. Growth disturbance secondary to osteonecrosis is difficult to determine until long after the treatment episode has passed. Consequently, the treating surgeon has little early feedback regarding the long-term consequences of management interventions. We therefore sought to devise a quantitative method to identify early evidence of growth disturbance related to osteonecrosis.

METHODS

The width and height of the epiphyses were measured on anteroposterior radiographs of the pelvis made twelve to eighteen months after successful closed reduction and on the latest available radiograph for each patient (mean age, 8.6 years). The epiphyseal index was calculated by dividing the height by the width. The radiographs were also scored for osteonecrosis with use of the Kalamchi and MacEwen classification system and were also assessed for sphericity with use of Mose rings.

RESULTS

Forty-seven patients with late-presenting developmental dysplasia of the hip who subsequently underwent successful closed reduction were included. An index of <0.357 on the twelve to eighteen-month post-treatment radiograph strongly predicted the development of a nonspherical femoral head on the latest radiograph (sensitivity, 0.83; specificity, 0.95; positive predictive value, 0.55; and negative predictive value, 0.99).

CONCLUSIONS

The height-to-width index appears to be a simple and quantifiable measurement of the severity of growth disturbance as a consequence of osteonecrosis following treatment for developmental dysplasia of the hip. It is predictive of asphericity at the time of intermediate-term follow-up and appears likely to predict asphericity at maturity, but this must be confirmed with follow-up to maturity. Unlike the currently used methods of assessing osteonecrosis, the index allows for the quantifiable evaluation of growth disturbance within a few years after the corrective procedure.

Three-dimensional computerized tomographic analysis of the deformity of lateral growth disturbance of proximal femoral physis

BACKGROUND

Lateral growth disturbance of the proximal femoral physis after treatment of developmental dysplasia of the hip, also known as type 2 avascular necrosis, has been described in a 2-dimensional (2D) plane with standard radiographs. It is not well described in the 3-dimensional plane using 3D computed tomography (CT) scan. The purpose of this study was to define the anatomy of the proximal femur after the lateral growth disturbance of the proximal femoral physis with 3D CT scans.

METHODS

Ten patients (11 hips) with lateral growth disturbance of the proximal femoral physis after treatment for developmental dysplasia of the hip (9 hips) and extracorporeal membrane oxygenation (2 hips), were studied with 2D and 3D CT methods. CT was done at an average age of 12.5 years (range, 9.8 to 16.69).

RESULTS

In addition to the typical valgus configuration in the coronal plane, increased antetorsion of the femur (10 of 11 hips) and increased anteversion of the femoral head (8 of 11 hips) were a common finding seen in the transverse plane. In 6 of 7 hips for which the CT scan was performed before the closure of the capital femoral epiphysis, the physeal bridge was seen to be located in the anterolateral (5 hips) or posterolateral (1 hip) area of the proximal femoral physis. The version of the femoral head was correlated to the location of the physeal bridge. Acetabular dysplasia was seen in 4 hips. In the 3D reconstruction view, flexion deformity of the femoral head was seen in 6 hips and lack of coverage at the anterolateral portion of the femoral head was observed in 6 hips.

CONCLUSIONS

The treating surgeon should be aware of the often marked antetorsion and also anteversion of the femoral head and neck associated with lateral growth disturbance of the proximal femoral physis. This knowledge allows surgical planning to correct rotational and sagittal plane correction of the proximal femur, which will allow normalizing hip mechanics. Acetabular side correction also may be needed if acetabular dysplasia is present.

LEVEL OF EVIDENCE

Level III, diagnostic study.

A radiological classification of lateral growth arrest of the proximal femoral physis after treatment for developmental dysplasia of the hip

BACKGROUND

After treatment of developmental dysplasia of the hip, lateral growth arrest of the physis of the proximal femur resulting in disturbance of the growth of the capital femoral epiphysis is not uncommon. The changes are usually not apparent until approximately the age of 9 years. The residual deformity has a variable prognosis at skeletal maturity. The purpose of this study was to assess the long-term impact of these proximal femoral changes on the function of the hips.

METHODS

We reviewed the natural history of 22 hips in 21 patients who had a lateral growth arrest of the physis of the proximal femur after treatment of developmental dysplasia of the hip. The average age at follow-up was 22 years. The radiographic changes in the proximal femur after the growth arrest were analyzed. Radiographic outcome was assessed using Severin criteria, with classes I and II being graded as satisfactory and classes III and IV being graded as unsatisfactory. The Iowa hip score was used to assess clinical outcome.

RESULTS

The consistent radiographic findings were a shortened lateral neck length in comparison with the medial neck length and lateral tilting of the capital femoral epiphysis, both of which were evident by an average age of 9 years. Overall, 41% of hips had a satisfactory radiological outcome according to the Severin classification. Two types of changes were observed in the proximal femur: a varus configuration (pattern A, 12 hips) and a valgus configuration (pattern B, 10 hips). Pattern A hips (varus) had a satisfactory result in 75% of the hips compared with none in pattern B hips (valgus).

CONCLUSIONS

Valgus orientation of the proximal femur (pattern B) leads to disruption of the Shenton line, progressive subluxation, and acetabular dysplasia which resulted in class III or class IV Severin grade hips leading to a poorer clinical and radiological outcome at long-term follow-up.

LEVEL OF EVIDENCE

Level III-Diagnostic study.

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.

Learning curves in orthopaedic surgery: a case for super-specialisation?

INTRODUCTION

The objective of this study was to assess if there is a significant learning curve in the treatment of developmental dysplasia of the hip.

PATIENTS AND METHODS

We followed up cases of developmental dysplasia of the hip treated by a single surgeon over a 12-year period. There were 96 cases, 56 treated by open reduction and 40 treated by closed reduction. Assessment was made of the incidence and degree of avascular necrosis in the treated hips, as a radiological outcome measure.

RESULTS

Plotting the cumulative percentage of satisfactory outcomes demonstrated an increasingly high percentage of satisfactory results with increasing number of procedures performed, i.e. as the surgeon progressed up the 'learning curve'.

CONCLUSIONS

This study demonstrates a learning curve in the treatment of developmental dysplasia of the hip. It may be possible to draw parallels to other treatments, and also support for the growing trend to specialisation.

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.

Screening for developmental dysplasia of the hip: a systematic literature review for the US Preventive Services Task Force

BACKGROUND

Developmental dysplasia of the hip (DDH) represents a spectrum of anatomic abnormalities that can result in permanent disability.

OBJECTIVE

We sought to gather and synthesize the published evidence regarding screening for DDH by primary care providers.

METHODS

We performed a systematic review of the literature by using a best-evidence approach as used by the US Preventive Services Task Force. The review focused on screening relevant to primary care in infants from birth to 6 months of age and on interventions used in infants before 1 year of age.

RESULTS

The literature on screening and interventions for DDH suffers from significant methodologic shortcomings. No published trials directly link screening to improved functional outcomes. Clinical examination and ultrasound identify somewhat different groups of newborns who are at risk for DDH. A significant proportion of hip abnormalities identified through clinical examination or ultrasound in the newborn period will spontaneously resolve. Very few studies examine the functional outcomes of patients who have undergone therapy for DDH. Because of the high rate and unpredictable nature of spontaneous resolution of DDH and the absence of rigorous comparative studies, the effectiveness of interventions is not known. All surgical and nonsurgical interventions have been associated with avascular necrosis of the femoral head, the most common and most severe harm associated with all treatments of DDH.

CONCLUSIONS

Screening with clinical examination or ultrasound can identify newborns at increased risk for DDH, but because of the high rate of spontaneous resolution of neonatal hip instability and dysplasia and the lack of evidence of the effectiveness of intervention on functional outcomes, the net benefits of screening are not clear.

Operative treatment for type II avascular necrosis in developmental dysplasia of the hip

Lateral growth disturbance of the proximal femur may occur after treatment of developmental dysplasia of the hip, although usually it is not recognized until the child is older. This resultant dysplasia is also known as Kalamchi and MacEwen Type II avascular necrosis. The valgus configuration of the proximal femur and associated acetabular dysplasia may need operative reconstruction. Our purpose in doing this study was to assess the results of reconstruction in these patients. We reviewed 24 patients (30 hips) with Type II avascular necrosis who had acetabular and/or proximal femoral osteotomy after treatment for developmental dysplasia of the hip. The results were assessed according to the timing and type of operation and were graded using the Severin classification (I and II satisfactory and III and IV unsatisfactory). All patients were followed up past skeletal maturity. At a mean followup of 22 years, 15 of 24 patients (17 of 30 hips) had a satisfactory result. The patients with hips that were reconstructed after the diagnosis of Type II avascular necrosis had more satisfactory results than those operated on before the diagnosis of (70% versus 50%) avascular necrosis. Patients with 10 of the 13 hips that had acetabular and femoral reconstruction had a satisfactory result.

Avascular necrosis after surgical treatment for development dysplasia of the hip

We reviewed the medical records of 101 patients with developmental dysplasia of the hip who were treated with Dega's (102 hips), or Salter's (42 hips)osteotomy preceded by open reduction and femoral intertrochanteric osteotomy. The minimal follow-up was 17 years. At the last follow-up, there were proximal fem-oral growth disturbances in 52 hips (36%). In 20 hips, the disturbances were graded as mild and in six as severe. We found significantly better clinical and radiological results in hips without avascular changes. Risk factors for the development of avascular necrosis were: involvement of the left side and surgical treatment initiated after 2 years of age without pre-operative traction and without femoral shaft shortening. We found that the incidence of avascular necrosis increased with the length of follow-up. The avascular necrosis influenced both clinical and radiological results.

Developmental dysplasia of the hip from six months to four years of age

Developmental dysplasia of the hip (DDH) denotes a wide spectrum of pathologic conditions, ranging from subtle acetabular dysplasia to irreducible hip dislocation. When DDH is recognized in the first 6 months of life, treatment with a Pavlik harness frequently results in an excellent outcome. In children older than 6 months, achieving a concentrically reduced hip while minimizing complications is more challenging. Bracing, traction, closed reduction, open reduction, and femoral or pelvic osteotomies are frequently used treatment modalities for children aged 6 months to 4 years. In the past, treatment recommendations have often been based on the patient's age. However, recent practice has placed more emphasis on addressing the specific disorder and avoiding iatrogenic osteonecrosis. The incidence of osteonecrosis of the femoral head has been reduced by avoiding immobilization of the hip in extreme abduction and by using femur-shortening osteotomies when appropriate. Pelvic osteotomy continues to gain favor for the treatment of selected patients over 18 months of age.

Acetabular development in developmental dysplasia of the hip complicated by lateral growth disturbance of the capital femoral epiphysis

BACKGROUND

Lateral growth disturbance of the capital femoral epiphysis is the most common type of physeal arrest complicating the treatment of developmental hip dysplasia. Although this type of physeal damage has been assumed to result in poor acetabular development, the natural history of dysplastic hips affected by this pattern of growth disturbance is still unclear. To investigate this issue, we evaluated acetabular development in a retrospective study of fifty-eight hips in forty-eight patients who had lateral physeal arrest after management of developmental hip dysplasia.

METHODS

Of the fifty-eight hips, thirty-six were reduced closed and twenty-two were reduced open. The average age of the patients was twenty-two months (range, three to ninety-seven months) at the time of the reduction and twenty-one years (range, ten to fifty-five years) at the time of the latest follow-up evaluation. Hips rated as Severin class I (an excellent result) or II (a good result) were defined as having a satisfactory result, and those rated as Severin class III (a fair result) or IV (a poor result) were considered to have an unsatisfactory result. Specific femoral head changes were sought in the complete radiographic files on all hips. Various radiographic parameters of hip integrity, including the degree of lateral tilt of the capital femoral epiphysis, were measured over time, and comparisons were made between hips classified as satisfactory and those classified as unsatisfactory at four time-points: before the reduction, at two years after the reduction, at six to eight years of age, and at the time of the final follow-up.

RESULTS

Lateral growth disturbance of the capital femoral epiphysis was first evident by an average of ten years of age (range, four to fourteen years of age). There was no consistent early pattern of changes in the epiphysis, physis, or metaphysis related to later development of valgus tilt of the epiphysis. Thirty-four hips (59 percent) were rated as satisfactory and twenty-four were rated as unsatisfactory at the latest follow-up evaluation. Hips classified as unsatisfactory exhibited poor acetabular development by an average age of seven years. The inclination of the epiphyseal plate became progressively more horizontal or even reversed over time; however, serial measurements of inclination were not significant predictors of Severin classification.

CONCLUSIONS

Lateral growth disturbance of the capital femoral epiphysis is not necessarily associated with poor acetabular development, as when dysplasia does occur it is generally evident prior to the identification of the physeal arrest. It is important to monitor acetabular development after reduction rather than search for radiographic changes of physeal arrest, which are difficult to detect in young children.

Avascular necrosis after treatment of DDH: the protective influence of the ossific nucleus

We retrospectively reviewed the results of open or closed reduction for developmental dysplasia of the hip (DDH) in 49 children younger than 12 months old, who had 57 hip dislocations. Group A (18 hips) developed partial or complete avascular necrosis (AVN), and group B (39 hips) did not develop AVN. Thirty-eight hips were treated by closed reduction, and 17 had open reduction. One patient with bilateral hip dislocation initially had closed reductions followed by bilateral open reduction 3 months later. With the numbers available for study, there was no significant difference in the occurrence of AVN with respect to variables such as preliminary traction, closed versus open reduction, Pavlik harness use, and age at the time of operative intervention. However, the presence of the ossific nucleus before reduction, detected either by radiographs (p < 0.001) or ultrasonography (p = 0.033) was statistically significant in predicting AVN. Only one (4%) of 25 hips with an ossific nucleus developed AVN, whereas 17 (53%) of 32 hips without an ossific nucleus before reduction developed AVN. Our results suggest that the presence of the ossific nucleus before closed or open reduction for DDH may decrease the risk of AVN.

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

Ischemic necrosis of the femoral head occurring after the treatment of congenital dysplasia of the hip can negatively affect the long-term prognosis of the involved hip. Some investigators have suggested that the presence of the ossific nucleus of the femoral head at the time of closed or open reduction is associated with a lower rate of ischemic necrosis. This finding, if verified, could lead to a delay in the treatment of a dislocated hip until ossification of the femoral head has begun, which may be well after the age when the patient has started to walk. We conducted a computerized search of the medical records at our two tertiary-care children's hospitals to identify all patients with congenital dysplasia of the hip who had had a closed or open reduction between January 1, 1979, and December 31, 1993. One hundred and twenty-four patients (153 hips) who satisfied the criteria for inclusion were identified. The ossific nucleus was present in ninety hips and absent in sixty-three. Closed reduction was used in 112 hips and open reduction, in forty-one. Ischemic necrosis was identified in five hips (3 percent): four (6 percent) of the sixty-three hips that did not have an ossific nucleus and one (1 percent) of the ninety hips that had an ossific nucleus at the time of the reduction. With the numbers available for study, we could not detect a difference between these two groups. The age at reduction (p > 0.99), the method of reduction (p = 0.611), previous treatment with a Pavlik harness (p = 0.592), the use of preliminary traction (p = 0.602), concomitant procedures (p > 0.99), and a failure of the primary closed reduction (p = 0.579) were not associated with the development of ischemic necrosis after reduction. In our analysis of patients who were managed over a fifteen-year period, the data did not support the hypothesis that the presence of an ossific nucleus at the time of reduction of a congenitally dislocated hip is associated with a lower prevalence of ischemic necrosis of the femoral head. Sound operative principles dictate that operative reduction of a congenitally displaced hip should be performed when the child can be safely placed under anesthesia and without regard to the presence or absence of the ossific nucleus.

Laser Doppler flowmetry during open reduction for developmental dysplasia of the hip

Laser Doppler flowmetry was used intraoperatively to monitor femoral head perfusion during open reduction of 13 congenital hip dislocations in 11 patients. Laser Doppler determinations ranged from 12 to 400 mV before reduction and 30 to 300 mV after reduction. Three patients had magnitude changes in excess of 50%. One had increased perfusion, and two had decreased blood flow. Avascular necrosis of the hip occurred in one patient that was not predicted by laser Doppler flowmetry. Femoral head perfusion measured 175 mV for the dislocated hip and 180 mV after reduction of the femoral head and completion of the pelvic osteotomy. The authors conclude that laser Doppler flowmetry is not a reliable method for monitoring femoral head perfusion during open reduction of the hip for developmental hip dysplasia.

Traction in developmental dislocation of the hip. Is its use justified?

Traction has been used for decades in the treatment of developmental dislocation of the hip. Traction is advocated to facilitate closed reduction and to decrease the need for open reduction. The use of prereduction traction also is advocated to decrease the incidence of proximal femoral growth disturbance (aseptic necrosis). Recently, several studies have called into question this widely accepted adjunct in the treatment of developmental dislocation of the hip. A critical look was taken at the use of traction in the treatment of developmental dislocation of the hip and whether its use can be justified by the existing medical literature was ascertained. Although there are several impressive reports of the positive effects of traction in developmental dislocation of the hip, there are no clinical or experimental studies on the direct effect of traction. There are also no well controlled studies to analyze the effect of traction as a single variable. Thus, it cannot be proven that traction alters the outcome of developmental dislocation of the hip treatment, and hence, there is only anecdotal basis for its use in the treatment of developmental dislocation of the hip.

Congenital dislocation of the hip in the older child. The effectiveness of overhead traction

We studied the use of overhead traction in the treatment of congenital dislocation of the hip in thirty-five children (fifty hips) whose mean age at the time of the diagnosis was thirty-three months (range, eighteen to seventy-two months). None of the children had had any previous treatment. The mean time in traction was twenty-three days (range, eight to thirty-six days). Closed reduction was successful for relocation of the femoral head in thirty-eight of the fifty hips; twenty of these hips needed no additional treatment, sixteen were treated with an innominate osteotomy because of severe acetabular dysplasia, and two needed femoral derotation and an innominate osteotomy to correct persistent subluxation. In the remaining twelve hips, closed reduction failed at the outset and an open reduction was necessary. Femoral shortening also was performed in seven of the twelve hips to maintain concentric reduction. After a mean duration of follow-up of forty-eight months (range, thirty-two to sixty-five months), thirty-three hips were rated as class 1; seven, as class 2; four, as class 3; and five, as class 4, according to the criteria of Severin. The remaining hip could not be so classified. Avascular necrosis developed in two hips that had been treated with closed reduction followed by Salter osteotomy and in three hips that had been treated with primary open reduction. We found that preliminary overhead traction facilitated closed reduction of untreated congenitally dislocated hips in children who were eighteen to seventy-two months old.

Closed reduction for congenital dysplasia of the hip. Functional and radiographic results after an average of thirty years

The functional and radiographic results of closed reduction in 152 congenitally dislocated hips of 119 patients who had been managed between 1938 and 1969 were reviewed retrospectively. The average age of the patients at the time of the reduction was twenty-one months (range, one to ninety-six months). At the time of the latest follow-up evaluation, the average age was thirty-one years (range, sixteen to fifty-six years). The average duration of follow-up was thirty years (range, fifteen to fifty-three years). At the latest follow-up evaluation, the Iowa hip rating averaged 91 points (range, 38 to 100 points) and the Harris hip score averaged 90 points (range, 33 to 100 points). Thirty-five hips were rated Severin Class I; thirty-five, Class II; twenty-eight, Class III; fifty-three, Class IV; and one, Class VI. Disturbance of growth in the proximal end of the femur occurred in ninety-one hips (60 per cent). Eight contralateral hips that had appeared normal also demonstrated disturbance of proximal femoral growth. In many hips, partial physeal arrest could not be determined for ten to twelve years after the reduction. Seventeen hips (twelve patients) had a total replacement when the patients were an average age of thirty-six years (range, nineteen to fifty-three years). Sixty-five hips (43 per cent) had radiographic evidence of degenerative joint disease. Patients who did not have a growth disturbance of the proximal end of the femur or evidence of subluxation tended to function extremely well for many years despite a radiographic result that was less than anatomical. Function tended to deteriorate with time, even in the absence of disturbance of growth in the proximal end of the femur. Despite generally good function at the latest follow-up evaluation, the prognosis for these patients remained guarded.