Elsevier

Journal of Orthopaedic Science

Volume 27, Issue 5, September 2022, Pages 1067-1072
Journal of Orthopaedic Science

Original Article
Radiological predictors associated with success of treatment for developmental dysplasia of hip using the Pavlik harness: A retrospective study

https://doi.org/10.1016/j.jos.2021.06.010Get rights and content

Abstract

Background

While various predictors of treatment outcome of Pavlik harness have been reported, appropriate indications for treatment and relationships between patient characteristics and outcome are unclear. The present study aimed to identify radiological predictors for successful Pavlik harness treatment of DDH at the initiation of treatment and investigate the progression of radiological characteristics after successful treatment.

Methods

One-hundred-forty-two of 527 infants who visited our hospital for secondary screening of DDH were treated with the Pavlik harness. One-hundred-eight hips of 108 infants experienced successful treatment and could be followed up until 3 years of age (group S); treatment was unsuccessful within the first 2 weeks for 22 hips of 21 infants (group F). We investigated the Graf classification and radiological parameters.

Results

We observed the ipsilateral-side measurements of distance A and B as defined by Yamamuro and Chene's method to be significantly smaller and greater, respectively, in group F compared with those of group S. Group F tended to exhibit the smaller distance A and larger distance B compared to the group S among the same Graf type. The cut-off values for successful treatment at were >7.4 mm at initiation of treatment for distance A and <11.2 mm for distance B. The acetabular index (AI) of the ipsilateral side at the initiation of treatment was significantly correlated with that at 1 and 3 years of age. Patients with an AI of >32° at the initiation of harness treatment were more likely to exhibit hip dysplasia at 3 years of age.

Conclusions

Radiographic parameters prior to the Pavlik harness could be predictors of treatment failure and DDH in the future. This study showed that AI at the initiation of treatment is associated with residual acetabular dysplasia, suggesting that radiographic assessment may be useful even considering the risks associated with radiation exposure.

Introduction

Developmental dysplasia of the hip (DDH) denotes a wide spectrum of pathological conditions, ranging from subtle acetabular dysplasia to irreducible hip dislocation with proximal femoral displacement. The incidence of DDH is estimated to be 4–7/1000 live births, but the true prevalence is difficult to quantify accurately [1]. In neonates with mild dysplasia and mild instability that are noted in the first few weeks of life, the clinical course may be benign, resolving by 8 weeks of age in up to 88% of cases [2]. However, neonates with instability and frank dislocation often have progressive dysplasia; spontaneous resolution of which is unlikely to occur beyond 6 months of age [3].

By walking age, the natural history of children with hip dysplasia at the more severe end of the disease spectrum (subluxation or dislocation) is less satisfactory than those treated successfully at a younger age. The Pavlik harness is one of the most common orthotic devices used to treat DDH in children; however, it can lead to potential complications if used incorrectly, including avascular osteonecrosis of the femoral head (ON) and femoral nerve palsy [4]. Various predictors of treatment failure of Pavlik harness have been reported, including sex [5], initial irreducibility [6], severe dislocation [7], and age at the time of treatment [8]. While several studies have attempted to correlate ultrasonographic findings with treatment outcomes [8,9], the interobserver variability in determining hip stability has been reported to be low to moderate [10].

Ultrasound is the superior imaging modality in children younger than six months of age, the time period where use of the Pavlik harness is most successful. Few studies have reported radiographic indicators for the Pavlik harness [11,12]. Limited information is also available on the clinical course of DDH after successful treatment using the Pavlik harness [13]. The present study aimed to 1) identify radiological predictors for successful Pavlik harness treatment of DDH at the initiation of treatment and 2) investigate the progression of radiological characteristics after successful treatment.

Section snippets

Materials and methods

The protocol of this study was approved by institutional review board of our institution and informed consent were obtained from all patients' parents. This study is a retrospective chart and radiographic review of all infants who visited our institution for secondary screening of DDH from January 2010 to December 2018. Limitation of hip abduction (<70°); asymmetry of skin creases of the thigh, buttock, or inguinal region; family history; female sex; or pelvic breech presentation at delivery

Results

Among the 527 infants who visited our hospital for secondary screening of DDH during the study period, 142 (15 males and 127 females) infants with subluxation or dislocation were treated using the Pavlik harness. Of these, treatment with the Pavlik harness was determined to be successful in 108 hips of 108 infants (13 males (12.0%) and 95 females (88.0%)) who could therefore be followed up until 3 years of age (comprising the group S) (3 years’ follow up ratio (108 infants/121

Discussion

The Pavlik harness is widely used to treat DDH in infants younger than 6 months. Although the incidence and risk factors of failure of the Pavlik harness have been reported, previous studies have been limited by incomplete assessment of patient factors, such as clinical examinations, and failure to review image evaluations at the time of diagnosis [8,9]. This study showed that distance A and B at the time of initiation of treatment were associated with success of treatment of Pavlik harness in

Conclusion

Radiographic evaluations including measurement of distance A and B prior to initiation of treatment could provide predictors of failure of the Pavlik harness. This study also shows that AI at the time of initiation of treatment is associated with the residual acetabular dysplasia, suggesting that radiographic assessment at the initiation of Pavlik harness may be useful even considering the risks associated with radiation exposure.

Funding

This study was supported by Takahashi Industrial and Economic Research Foundation (Daisuke Takahashi).

Declaration of competing interest

The authors declare that they have no conflict of interest.

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    These authors contributed equally to this manuscript.

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