LAUSR

Background: We asked whether patient-specific factors and ultrasound (US) measurements of hip dysplasia severity at initial examination influence short-term residual acetabular dysplasia in patients successfully treated with Pavlik harness for developmental hip dysplasia. Methods: After IRB approval, 134 hips (84 patients) successfully treated by the Pavlik method between August 2011 and October 2014 with follow-up at 12 months of age were identified. Early successful treatment was defined as normal examination and US after approximately 12 weeks of Pavlik treatment. Multivariate linear and logistic regression models were used to identify factors associated with acetabular index (AI) measurements at 12 months as well as factors associated with an increase in AI between the 6- and 12-month timepoints (dysplastic progression). Results: The study consisted of 134 hips (84 patients). The distribution of dysplastic, Barlow, and Ortolani hips was 44.8% (N=60), 30.6% (N=41), and 24.6% (N=33), respectively. The crude incidence of residual dysplasia at the 6-month visit (AI>30 degrees) was 11.7% (12/102). The incidence of residual dysplasia at the 12-month visit (AI>28 degrees) was 11.8% (13/111). Graf type was the only variable associated with AI values at the 12-month visit (mean difference: Graf type-IV—Other, 2.6; 95% confidence interval, 0.3-4.9; P=0.026). Conclusions: The risk of residual acetabular dysplasia after normal hip US following Pavlik treatment is not negligible. Radiographic surveillance is warranted to monitor and screen for dysplasia progression. Patients with dislocated Graf type-IV hips at diagnosis are at increased risk of residual acetabular dysplasia at 1 year after successful treatment with the Pavlik method. Level of Evidence: Level III—therapeutic study.