Surgical results and complications of developmental dysplasia of the hip--one stage open reduction and Salter's osteotomy for patients between 1 and 3 years old.

Background: Reports of the efficacy of Salter's osteotomy have often been based on groups of patients with complex disease conditions and treatment. The purposes of this study were to document the results of patients with well-defined conditions, focusing on the onset and sequelae of osteonecrosis.

Methods: The study participants consisted of 63 patients with unilateral hip dislocation who had undergone one-stage open reduction and Salter's innominate osteotomy between the ages of 1 and 3 years. The results were evaluated clinically by McKay's classification and radiologically by the modified Severin's classification. Early signs of osteonecrosis were identified by neck widening, epiphysis fragmentation, and presence of a metaphyseal growth disturbance line in the first year after the operation.

Results: After a follow-up of 10 years on average, good clinical and radiographic results were noted in 89% and 92% of the patients, respectively. Osteonecrosis occurred in 30 hips, of which 14 subsequently developed femoral head deformity. Residual dysplasia was noted in 5 hips, mostly resulting from late-onset coxa valga. Eighty-five percent of the hips without osteonecrosis and 53% of the hips with osteonecrosis (p < 0.05) were classified as Severin class 1. No pre-operative factors were found to be associated with the occurrence of osteonecrosis.

Conclusion: One-stage open reduction and Salter's osteotomy was an effective treatment for developmental dysplasia of the hip after walking age. However, parents must be informed of the two major complications, osteonecrosis and residual dysplasia, that can lead to long-term morbidity.