Avascular necrosis after surgical treatment for development dysplasia of the hip.

We reviewed the medical records of 101 patients with developmental dysplasia of the hip who were treated with Dega's (102 hips), or Salter's (42 hips)osteotomy preceded by open reduction and femoral intertrochanteric osteotomy. The minimal follow-up was 17 years. At the last follow-up, there were proximal fem-oral growth disturbances in 52 hips (36%). In 20 hips, the disturbances were graded as mild and in six as severe. We found significantly better clinical and radiological results in hips without avascular changes. Risk factors for the development of avascular necrosis were: involvement of the left side and surgical treatment initiated after 2 years of age without pre-operative traction and without femoral shaft shortening. We found that the incidence of avascular necrosis increased with the length of follow-up. The avascular necrosis influenced both clinical and radiological results.