Zhang Z, Li H, Li H, et al. - In this study, the midterm outcome of closed reduction (CR) was analyzed for developmental dysplasia of the hip (DDH) among different age groups, and to analyze and identify risk factors for the failure of this procedure. Researchers retrospectively examined the clinical data of 107 DDH patients, who received CR. They classified data into three groups according to initial treatment age (Group I: younger than 12 months; Group II: 12 months to less or equal to18 months; Group III: older than 18 months). They evaluated the presence of avascular necrosis (AVN), residual acetabular dysplasia (RAD), re-dislocation, and further surgeries. This study enrolled a sum of 107 patients (156 hips) undergoing CR procedure with a median age at an initial reduction of 13.0 ± 5.4 months (range, 4 to 28 mo). This study's findings demonstrate that severe DDH individuals older than 18 months with CR procedure may result in a high risk of RAD complication. There was a relationship between re-dislocation and pre-op IHDI IV, walking. It was indicated that individuals, who are older than 12.5 months or have a pre-op AI of 38.7° or a post-op AI of 26.4°, are also more seemingly to fail of CR procedure.