Lateral growth disturbances of the capital femoral epiphysis after nonoperative treatment of late developmental dislocation of the hip: thirty-five cases followed to skeletal maturity.

The purpose of this study was to evaluate the effect of type 2 growth disturbances in the developing hip and compare it with other treated hips without evidence of growth arrest. Radiographic data of 117 children (155 hips) with late developmental dislocation of the hip treated by closed reduction at an average age of 14.9 months and followed to skeletal maturity were retrospectively reviewed. Depending on the presence of lateral growth disturbances, our patients were divided into 2 groups similar with regard to age and treatment methods. Lateral physeal arrest was evident at an average age of 8.9 years in 23% of these hips. Seventy-six percent of these hips with type 2 avascular necrosis were classified as Severin classes 1 and 2. One quarter of them had no deformity of femoral head, 8 had deformity of 2 mm or less, and 18 more than 2 mm. There was no statistical difference in satisfactory and unsatisfactory results or most parameters describing the acetabulum between the 2 groups. Lateral tilting of the proximal femoral epiphysis in most cases does not affect final radiologic results. It is a mild form of avascular necrosis and indications for secondary operative procedures are mostly related to natural history of the disease rather than to lateral physeal arrest.