The utility of ultrasound and plain radiographs in the management of developmental dysplasia of the hip.

The purpose of this study is to assess the utility of follow-up radiological imaging in the management of developmental dysplasia of the hip (DDH) in patients successfully treated with the Pavlik harness. A retrospective review was conducted on all children under 6 months diagnosed with DDH at a tertiary pediatric hospital between January 2004 and December 2018. Inclusion criteria included successful Pavlik harness treatment following a standardized protocol with complete radiological documentation at 2 years of age. Ultrasonography was reviewed to measure the α and β angles and Graf classification. Anteroposterior pelvic radiographs were evaluated for the acetabular index and residual acetabular dysplasia. Seventy-eight hips from 57 infants were included in this study. The mean 6-month, 12-month and 2-year acetabular index of Graf I, IIa and IIc hips on ultrasound at 12 weeks were within the normal range according to age. There were no Graf IIb, IId, III and IV hips. All infants had normal radiographs at 2 years follow-up. The 6- and 12-month residual dysplasia rates in patients with DDH normalization at 12 weeks and 6 months range from 2.5 to 8.82%. Regardless of when the acetabular index normalized, all patients eventually had normal hip radiographs at 2 years of age. Following a standardized protocol, patients undergoing Pavlik harness treatment for DDH with Graf I and IIa hips at 12 weeks are likely to have normal plain radiographs at discharge. The incidence of residual dysplasia is very low and hence, radiographic surveillance is probably unnecessary until discharge at 2 years. Level II, retrospective study.