Closed reduction and dynamic cast immobilization in patients with developmental dysplasia of the hip between 6 and 24 months of age

Background Closed reduction and spica cast is still the preferred treatment option for children presenting with developmental dysplasia of the hip (DDH) after the age of 6 months. This study aims to investigate the outcomes of patients with DDH treated by closed reduction and dynamic cast immobilization. Methods In total, 159 patients (mean age 15.6 ± 4.2 months; 172 hips) were treated with a dynamic cast immobilization for 3 months, followed by an abduction brace until a stable concentric reduction was achieved. Radiological examination was performed at each follow-up visit to assess reduction, redislocation rate and presence of avascular necrosis (AVN) of the femoral epiphysis. Final radiographic results were evaluated with the Severin classification. Results The redislocation rate was 4.1% (7/172); the overall AVN rate was 14.5% (grade II: 16 hips; grade III: 5 hips; grade IV: 3 hips). At last follow-up visit, the mean age of patients was 61.6 ± 21.3 months (range 30.8–141), and the mean acetabular index was 22.6° ± 5.6°; 67.3% of the hips had Severin type I radiographic criteria, 8.5% had type II, 23.6% had type III, and 0.6% had type IV. Conclusions Dynamic cast is an alternative to spica cast immobilization in DDH patients undergoing closed reduction. It has similar redislocation and AVN rates compared to standard spica cast immobilization, as reported by previous studies.