Medial Open Reduction for Developmental Dysplasia of the Hip Compared to Delayed Anterior Approach: Is There a Difference at Skeletal Maturity?

Introduction Children with developmental hip dislocation (DDH) that have failed closed reduction or presented late may be treated with open reduction either via the medial approach (MOR), or via a delayed anterolateral (AOR) approach. There is no consensus on which provides better outcomes. This updated prospective cohort study aims to compare the approaches at long term follow up. Methods Thirty hips in 25 children (MOR) and 19 hips in 18 children (AOR) who were treated for DDH in our centre were identified. All patients included had reached skeletal maturity by final follow up as defined by the Oxford Bone Score. The most recent pelvic radiograph was assessed for proximal femoral growth disturbance (PFGD), centre edge angle, Tonnis angle and Severin grade. The immediate postoperative MRI was retrospectively assessed in the MOR group to evaluate the hip abduction angle in cast. Results We report our comparative rates of avascular necrosis, radiological outcomes and secondary interventions between our MOR and AOR cohorts. Hip spica abduction angle ≥60⁰ following MOR was found to be associated associated with development of PFGD. At time of final follow up six MOR hips underwent femoral or acetabular realignment surgery. Two AOR hips underwent the same and required total hip replacement subsequently. Conclusions Incidence of PFGD changed in both cohorts over the follow up period. The MOR group required more secondary surgeries for persisting dysplasia but the AOR group had more young adult osteoarthritis. Hip abduction in a body spica ≥60⁰ should be avoided after MOR.