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

Reapplication of the Pavlik Harness for Treatment of Developmental Dysplasia of the Hip After Initial Pavlik Harness Failure

OBJECTIVE

The Pavlik harness (PH) has been widely used as the standard treatment for infants with developmental dysplasia of the hip (DDH). When the initial application of the PH fails, alternative treatments, such as closed reduction, open reduction, and reapplication of the PH will be considered. Compared with other treatments, reapplication of the PH offers certain advantages, including simplicity and reduced physical, and psychological stress, on both infants and caregivers. This study aims to investigate the effectiveness of reapplying the PH in patients with DDH.

METHODS

This study included patients with DDH (complete dislocation) who were treated by reapplication of PH between 1988 and 2012. Patients who were able to follow-up for more than 5 years were included. We examined the reduction rate and several factors to identify indicators associated with successful reduction during reapplication, including age, sex, side of hip dislocation, and the presence of the Ortolani sign. At the final follow-up, hip development was assessed using the Severin classification, whereas avascular necrosis (AVN) was evaluated using the Kalamchi classification and the Salter criteria.

RESULTS

A total of 56 patients (48 females and 8 males) and 57 hips were included in this study. The mean age at first and second application of PH was 4.2 months old (range: 0.12 to 6.4), and 5.8 months old (3.0 to 11.4), respectively. The reduction rate was 49% (28 out of 57 hips). Among the successfully reduced hips, the AVN rate was 3.6% (1 out of 28 hips). The Severin classification revealed 27 hips in class I and 1 hip in class III. Statistical analysis indicated a significantly higher proportion of left hip involvement in the reduction group (85% vs 41%, χ 2 test, P < 0.001). Although not statistically significant, the rate of positive Ortolani sign tended to be higher in the reduction group (61% vs 38%, χ 2 test, P = 0.06).

CONCLUSION

The reapplication method demonstrated a 49% reduction rate and a low AVN rate of 3.6% in our study. It is worth considering for patients who fail the initial PH treatment, particularly in cases of left-side dislocation and a positive Ortolani sign during the initial application.

Evaluation of Anterior Coverage in Children With Developmental Dysplasia of the Hip Using Transverse Magnetic Resonance Imaging at 2 Years Is Predictive of Future Radiographic Coverage

BACKGROUND

Although normal anterior acetabular coverage provides stability to the hip, acetabular retroversion leads to femoroacetabular impingement related to hip osteoarthritis. Previous studies have focused on acetabular version and anteroposterior coverage in children with developmental dysplasia of the hip (DDH); however, the correlation between anteroposterior coverage and acetabular development is unclear. We measured anteroposterior acetabular coverage in DDH patients using transverse magnetic resonance imaging (MRI) and subsequent bony acetabular growth, and evaluated the correlation of those findings.

METHODS

We evaluated 37 DDH (dislocations) in 36 patients who underwent MRI at 2 years of age. The mean age was 2.2±0.3 years at the time of MRI (1.6±0.4 y after reduction) and 6.0±0.1 years at the time of plain radiography for the Severin classification. On MRI scans, we measured the cartilaginous center-edge angle (CCEA) and cartilaginous acetabular-head index (CAHI) in the coronal plane and the anterior and posterior cartilaginous center-edge angles (AC-CEA and PC-CEA, respectively) in the transverse plane. Severin I or II was defined as a good outcome and III or IV as a poor outcome.

RESULTS

In the evaluations conducted at 2 years of age, the mean CCEA, CAHI, AC-CEA, and PC-CEA were 14±9 degrees, 66%±10%, 39±8 degrees, and 77±7 degrees, respectively; the CEA at 6 years of age was 13±7 degrees. Twelve and 25 hips were classified in the good and poor outcome groups, respectively. Although CCEA, CAHI, and AC-CEA were significantly associated with the outcome in a single regression analysis ( P <0.05), only AC-CEA was significant in the multiple regression analysis with a stepwise selection method ( P =0.018). The cutoff AC-CEA value for a good outcome was 38 degrees (sensitivity, 67%; specificity, 68%) using a receiver operating characteristic curve.

CONCLUSIONS

Among MRI findings for acetabular cartilaginous morphology, AC-CEA was strongly associated with the outcome. Anteroposterior coverage was correlated with bony acetabular growth in childhood, and anterior coverage was particularly important for subsequent acetabular growth.

LEVEL OF EVIDENCE

Level IV-case series.

Fate of hips complicated by avascular necrosis of the femoral head following reconstructive surgery in nonambulatory patients with cerebral palsy

The purpose of this study was to evaluate the influence of avascular necrosis of the femoral head (AVN) following hip reconstructions on the future hip development of cerebral palsy (CP) patients. A retrospective study of 394 hips in 205 nonambulatory patients with spastic CP who underwent reconstructive hip surgery was performed. The mean age at surgery was 7.3 ± 2.4 years. The mean follow-up duration was 5.6 ± 2.7 years, and the mean age at the latest follow-up was 12.8 ± 3.4 years. AVN was classified in terms of its severity and location. Femoral head remodelling was assessed by the spherical index and the Mose circle. An unsatisfactory radiological outcome was defined as having a migration percentage of more than 30% at the final follow-up. AVN was observed in 169 (42.9%) hips. Older age at the time of surgery, higher preoperative migration percentage, and open reduction procedures were predictors for the development of AVN. Hips with AVN confined to the lateral epiphysis, and AVN involving the entire epiphysis with preserved height experienced successful remodelling. 27 (65.9%) of the 41 hips with unsatisfactory outcomes experienced AVN. Younger age, higher postoperative migration percentage, and occurrence of AVN were related to unsatisfactory outcomes. The highest incidence of failed remodelling and unsatisfactory outcomes were observed in hips with entire epiphyseal involvement and more than 50% loss of its height. AVN following hip reconstructions is not necessarily associated with poor hip development, however, depending on the severity and location, it is a prognostic factor for unsatisfactory radiological outcomes.

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.

What Are the Rate and Risk Factors for Developing a Complication With the Pavlik Method for the Treatment of Hip Dysplasia?

BACKGROUND

The Pavlik method for the treatment of developmental dysplasia of the hip (DDH) has been proven successful for over 85 years. The high success rate and reproducibility have made it the mainstay of treatment.

METHODS

We performed a retrospective cohort study of patients with DDH treated with the Pavlik method between September 2016 and August 2018 with at least 24 months of follow up in a single academic center. We excluded patients with neuromuscular conditions, teratologic dislocations, and arthrogryposis. We identified and included a total of 307 patients in the analysis. There were 66 patients with dysplasia, 97 with instability, and 144 with a dislocation. Data collected included age at initiation of the Pavlik method, diagnosis (isolated dysplasia, subluxation, or dislocation), duration of treatment, follow up duration and any complication. At final follow up, anteroposterior radiographs of the pelvis were used to determine the Severin classification.

RESULTS

Major complications were proximal femoral growth disturbance (5.8%) and femoral nerve palsy (0.98%). Multivariate analysis showed that an initial diagnosis of a dislocated hip (odds ratio, 2.20; P<0.01), was significantly associated with developing a complication. At final follow up, we found Severin type I or II radiographic findings in 100% of patients with dysplasia, 95% of patients with instability and 54% of patients with dislocation (P=0.001).

CONCLUSIONS

Complications are not entirely uncommon when the Pavlik method is used for the treatment of DDH. The overall rate of major complications was 7%. The Pavlik method is safe, and independent risk factors for complications were being over 5 months of age and having a dislocated hip at initial presentation.

LEVEL OF EVIDENCE

Level IV-cohort study.

The incidence of avascular necrosis following a cohort of treated developmental dysplasia of the hip in a single tertiary centre

PURPOSE

Avascular necrosis (AVN) may occur following treatment for developmental dysplasia of the hip (DDH). The primary aim of this study was to identify the incidence of AVN in a cohort of patients treated for DDH. Secondary aims were to classify AVN using available classification systems, analyze the correlation between the systems and investigate their relationship with the age at diagnosis of DDH.

METHODS

An 11-year retrospective study was carried out at a single tertiary centre, using data from the clinical portal (patient records database) and IMPAX (system used to store plain radiographic images). Clinical details (patient demographics and outcomes) and plain radiographic images were used to identify cases of DDH and categorize cases of AVN using available classification systems: Tonnis and Kuhlmann, Kalamchi and McEwen, Bucholz and Ogden and Salter. Severin was used to assess final clinical outcome.

RESULTS

In total, 405 (522 hips) cases of DDH were identified, of which 213 resolved without treatment, 93 were treated conservatively and 99 surgically. Only treated cases were included in the analysis (n = 192). AVN (45/99; 45.5%) was found to occur only postoperatively. A positive correlation was present between age at presentation and severity of AVN as classified according to Salter's criteria (chi-squared p value < 0.01).

CONCLUSION

AVN incidence was 23.4% (45/192) and only occurred in surgically treated patients. Older age at diagnosis was associated with a higher incidence of AVN, as defined according to Salter's criteria. The classification systems appeared to show no correlation amongst each other (p-value < 0.01).

LEVEL OF EVIDENCE

III - Retrospective cohort study.

MRI risk factors for development of avascular necrosis after closed reduction of developmental dysplasia of the hip: Predictive value of contrast-enhanced MRI

Purpose

The purpose of this study was to identify imaging risk factors on contrast-enhanced hip MRI after closed reduction of developmental dysplasia of the hip (DDH) that could predict future development of avascular necrosis (AVN) of the femoral head.

Materials and methods

Fifty-eight infants (F: M = 53: 5, aged 3–18 months) who underwent immediate postoperative contrast-enhanced hip MRI after closed reduction of DDH were included in this study. Quality of reduction (concentric vs eccentric reduction with or without obstacles), abduction angle of the hip, presence of ossific nucleus, and pattern of contrast enhancement of the femoral head were retrospectively evaluated on MRI. Interobserver agreement of contrast enhancement pattern on MRI were evaluated by two radiologists. Development of AVN was determined through radiographic findings at 1 year after reduction.

Results

AVN of the femoral head developed in 13 (22%) of 58 patients. Excessive abduction of the hip joint (OR 4.65, [95% CI 1.20, 18.06] and global decreased enhancement of the femoral head (OR 71.66, [95% CI 10.54, 487.31]) exhibited statistically significant differences between the AVN and non-AVN groups (P < 0.05). Eccentric reduction (P = 0.320) did not show statistically significant difference between two groups and invisible ossific nucleus (P = 0.05) showed borderline significance. Multi-variable logistic regression indicated that global decreased enhancement of the femoral head was a significant risk factor of AVN (OR 27.92, 95% CI [4.17, 350.18]) (P = 0.0031). Interobserver agreement of contrast enhancement pattern analysis and diagnosis of AVN were good (0.66, 95% CI [0.52, 0.80]).

Conclusion

Contrast-enhanced hip MRI provides accurate anatomical assessment of the hip after closed reduction of DDH. Global decreased enhancement of the femoral head could be used as a good predictor for future development of AVN after closed reduction of DDH.

Evolution of concentricity after closed reduction in developmental dysplasia of the hip

AIMS

The goal of closed reduction (CR) in the treatment of developmental dysplasia of the hip (DDH) is to achieve and maintain concentricity of the femoral head in the acetabulum. However, concentric reduction is not immediately attainable in all hips and it remains controversial to what degree a non-concentric reduction is acceptable. This prospective study is aimed at investigating the dynamic evolution of the hip joint space after CR in DDH using MRI.

METHODS

A consecutive series of patients with DDH who underwent CR since March 2014 were studied. Once the safety and stability were deemed adequate intraoperatively, reduction was accepted regardless of concentricity. Concentricity was defined when the superior joint space (SJS) and medial joint space (MJS) were both less than 2 mm, based on MRI. A total of 30 children, six boys and 24 girls, involving 35 hips, were recruited for the study. The mean age at CR was 13.7 months (3.5 to 27.6) and the mean follow-up was 49.5 months (approximately four years) (37 to 60). The joint space was evaluated along with the interval between the inverted and everted limbus.

RESULTS

Only three hips (8.6%) were fully concentric immediately after CR. During follow-up, 24 hips (68.6%) and 27 hips (77.1%) became concentric at six months and one year, respectively. Immediate SJS after CR decreased from 3.51 mm to 0.79 mm at six months follow-up (p = 0.001). SJS in the inverted group decreased from 3.75 mm to 0.97 mm at six months follow-up. SJS or MJS in the everted group were less than those in the inverted group at each time of follow-up (p = 0.008, p = 0.002).

CONCLUSION

A stable, safe but non-concentric reduction achieved before the age of two years appears to improve over time with nearly 80% of hips becoming fully concentric by one year. Cite this article: Bone Joint J 2020;102-B(5):618-626.

Developmental dysplasia of the hip and clubfoot treated by Pavlik and Ponseti methods

Children having both typical developmental dysplasia of the hip (DDH) and clubfoot are rare, and early treatments of both conditions are recommended. The aim of this study was to evaluate the effects of the Ponseti method of clubfoot treatment on hips with DDH. After institutional review board approval, we identified children treated by the Ponseti and Pavlik methods between 2003 and 2016. During the Ponseti method treatment, the duration of manipulations, number of casts, tenotomies performed, and days in clubfoot orthosis were recorded. During DDH treatment, we registered duration for Pavlik and hip brace usage. Hips had dynamic sonography and radiographic evaluations. The cases were grouped according to the combination of DDH and clubfoot treatments: (a) concurrent, (b) sequential, and (c) hip observation. Seven cases of DDH and clubfoot were identified. The average number of Ponseti casts was 5.8 (range: 4-8 casts). The average number of days following the post-Achilles-tenotomy casting to the end of clubfoot bracing was 870 days (range: 90-1605 days). Eleven (four bilateral cases and three unilateral) clubfeet were corrected initially by the Ponseti method. The average number of days for Pavlik harness treatment was 74 (range: 10-126 days). Additionally, a hip orthosis was utilized in three children for an average of 131 days. At follow-up, all children had a high femoral neck-shaft angle averaging 152° (range: 144°-164°). One child (case 5) developed avascular necrosis of the femoral head, Kalamchi type I. Children with typical and nonsyndromic DDH and clubfoot treated by Pavlik harness and Ponseti methods are associated with abnormal hip development (coxa valga).

Value of the 'clicky hip' in selective screening for developmental dysplasia of the hip

AIMS

The aim of this study was to review the value of accepting referrals for children with 'clicky hips' in a selective screening programme for hip dysplasia.

PATIENTS AND METHODS

A single-centre prospective database of all referrals to the hip clinic was examined to identify indication for referrals, diagnosis, and treatment. All patients referred received a standardized ultrasound scan and clinical examination by an orthopaedic consultant.

RESULTS

There were 5716 children referred to the orthopaedic hip clinic between 1 June 2014 and 26 September 2018. In all, 1754 children (30.1%) were referred due to 'clicky hip' with no additional risk factors or indications for ultrasound scan. A total of 123 children (7.1%) referred with 'clicky hip' and no additional risk factors or examination findings had an abnormal initial hip ultrasound, including 16 children (0.9%) with dysplastic hips. Of the 141 children who required treatment in a Pavlik harness during the study period, 23 (16%) had been referred with a 'clicky hip' and no additional risk factors or examination findings, including six children with Graf 3 or 4 hips.

CONCLUSION

There is significant value in reviewing children with an isolated 'clicky hip'. Many children who require treatment are referred to the orthopaedic service as 'clicky hip' with no additional risk factors. In a pragmatic pathway with a diverse population of clinicians performing baby checks, 'clicky hip' is an important indication for referral and should not be discarded. Cite this article: Bone Joint J 2019;101-B:635-638.

Predictors of femoral shortening for pediatric developmental hip dysplasia surgery: an observational study in 435 patients

Background

Open reduction of the congenitally dislocated hip may not be possible without femoral shortening. The goal of this study is to develop a prognostic prediction model for the need of femoral shortening in children undergoing anterior open reduction for the treatment of developmental dysplasia of the hip (DDH). The secondary objective was to determine if femoral shortening influences the risk of adverse events.

Methods

A cohort from February 1, 2008 thru July 31, 2017 was studied retrospectively at a single centre. Patients between the age of 1 and 8 years, having international hip dysplasia institute (IHDI) grade 3 and 4, undergoing primary anterior open reduction for DDH were included in the study. The outcome of interest was femoral shortening, and the potential predictors were age, sex, side, body mass index and IHDI grade. Logistic regression was employed to identify the independent predictors and was followed by internal validation using bootstrapping. In addition, complications encountered were recorded and analysed.

Results

A total of 548 hips in 435 patients were included. Median follow-up (interquartile range) was 27 (13–48.25) months. Femoral shortening was needed on 119 hips. Factors that increased the probability of femoral shortening in the reduced model were age, male gender, and IHDI grade 4. Adjusting for IHDI and the addition of pelvic osteotomy, the probability of recurrence was lower when femoral shortening is included and higher with increased patient age. There were more deep infections when femoral shortening is added. Femoral shortening did not affect the occurrence of avascular necrosis.

Conclusion

In addition to age and superior displacement of the femoral head, male gender is considered to be an independent predictor for needing femoral shortening. Studying the probability of femoral shortening in DDH surgery may optimize family education, operating room preparation, and operative time utilization. Moreover, there appears to be less risk of recurrence when femoral shortening is performed at the cost of higher probability of deep surgical site infection.

Three-dimensional MRI Analysis of Femoral Head Remodeling After Reduction in Patients With Developmental Dysplasia of the Hip

BACKGROUND

Previous reports on patients with developmental dysplasia of the hip (DDH) showed that the prereduced femoral head was notably smaller and more nonspherical than the intact head, with growth failure observed at the proximal posteromedial area. We evaluated the shape of the femoral head cartilage in patients with DDH before and after reduction, with size and sphericity assessed using 3-dimensional (3D) magnetic resonance imaging (MRI).

METHODS

We studied 10 patients with unilateral DDH (all female) who underwent closed reduction. Patients with avascular necrosis of the femoral head on the plain radiograph 1 year after reduction were excluded. 3D MRI was performed before reduction and after reduction, at 2 years of age. 3D-image analysis software was used to reconstruct the multiplanes. After setting the axial, coronal, and sagittal planes in the software (based on the femoral shaft and neck axes), the smallest sphere that included the femoral head cartilage was drawn, the diameter was measured, and the center of the sphere was defined as the femoral head center. We measured the distance between the center and cartilage surface every 30 degrees on the 3 reconstructed planes. Sphericity of the femoral head was calculated using a ratio (the distance divided by each radius) and compared between prereduction and postreduction.

RESULTS

The mean patient age was 7±3 and 26±3 months at the first and second MRI, respectively. The mean duration between the reduction and second MRI was 18±3 months. The femoral head diameter was 26.7±1.5 and 26.0±1.6 mm on the diseased and intact sides, respectively (P=0.069). The ratios of the posteromedial area on the axial plane and the proximoposterior area on the sagittal plane after reduction were significantly larger than before reduction (P<0.01).

CONCLUSIONS

We demonstrated that the size of the reduced femoral head was nearly equal to that of the intact femoral head and that the growth failure area of the head before reduction, in the proximal posteromedial area, was remodeled after reduction.

LEVEL OF EVIDENCE

Level IV-case series.