Study on the efficacy of brace therapy for developmental dysplasia of the hip with Graf IIc and greater severity.

To assess changes in the α and β angle with brace treatment in DDH classified as Type Graf IIc, D, III, and IV; to study the α angle threshold that can predict the treatment effect; to analyze the effective rate in different groups. A retrospective study was conducted on children from 2013 to 2018 with Graf type IIc and greater diagnosed with ultrasound (US). Brace therapy was applied to 356 patients, with 423 affected hips (Graf IIc: 202 hips; Graf D: 17 hips; Graf III: 118 hips; and Graf IV: 86 hips). For follow-up efficacy analyses using US, X-ray and clinical examination, based on the success of early treatment of the brace, the outcomes were divided into 'effective' and 'noneffective' groups. The statistical results showed that the α angle increased ( P  < 0.05) and the β angle decreased ( P  < 0.05). When α≥43°, the accuracy of success with early treatment was 95.95%. The overall effective rate of bracing treatment was 74.70%. Children with α ≥ 43° are recommended to receive brace therapy as soon as possible and demonstrate the best effects. The effective rate varies across different Graf types and the age at treatment initiation. Brace therapy is more effective for Graf IIc and D hips compared to Graf III and IV.