Risk Factors for Failure of Pavlik Harness Treatment in Infants With Dislocated Hips That Are Evaluated by Dynamic Sonography

Background: Frankly dislocated hips occur in similar to 1% to 3% of infants with developmental dysplasia of the hip and are often difficult to treat. In the most severely dislocated hips, the femoral head is positioned outside the posterior/lateral rim of the acetabulum and is irreducible, that is, the femoral head will not reduce by positioning the leg. The purpose of this study was to determine risk factors, using univariate and multivariate analyses, for Pavlik harness failure in infants who initially presented with irreducible/dislocated hips (confirmed by dynamic sonography). Methods: Following institutional review board approval, 124 infants (170 hips) with frankly dislocated hips treated using a Pavlik harness between 2000 and 2018 were evaluated. Patients' demographic characteristics, clinical findings, dynamic sonographic findings (dislocated-fixed vs. dislocated-mobile), age at onset of Pavlik harness treatment, duration of harness usage, and follow-up treatments were recorded. Univariate analyses were used to determine risk factors for treatment failure. Results: In frankly dislocated hips (confirmed by dynamic sonography to be positioned outside the posterior/lateral rim of the acetabulum), Pavlik harness treatment was successful in 104 of 170 hips (61%) while it failed in 66 hips. Mean follow-up was 4.86 +/- 4.20 years. Univariate analysis determined the risk factors to be onset of treatment after the seventh week of age (P=0.049) and initial mobility (dislocated-fixed group) (P<0.001) by dynamic sonography. In addition, multivariate analysis (P=0.007) showed infants of multigravida mothers (non-firstborn) to be another risk factor for failure. Six percent of hips with no risk factors failed Pavlik harness treatment, those with 1 risk factor had 42% failure, 2 risk factors had 69% failure, and all 3 risk factors had 100% failure. Conclusions: In our patients with frankly dislocated irreducible hips, 39% of hip failed Pavlik harness treatment. Independent multivariate, logistic regression analysis, and multivariate analysis determining the risk factors for failure of Pavlik harness treatment were onset of treatment after the seventh week of age, infants of multigravida mothers, and initial hip mobility (fixed-dislocated hips) by dynamic sonography.