Post-reduction avascular necrosis in congenital dislocation of the hip.

Twenty-five patients with thirty congenitally dislocated hips in which avascular necrosis developed after closed reduction were followed for an average of thirty-nine years from the time of reduction. Twenty-four of the thirty hips had moderate or severe osteoarthritis and twenty-two of the twenty-five patients had significant pain or loss of function, or both, by the time they were forty-two years old, The deformities produced by avascular necrosis that were related to osteoarthritis included: (1) loss of sphericity of the femoral head, (2) persistent lateral and proximal subluxation, (3) irregularity of the medial part of the femoral head, and (4) acetabular dysplasia. The study suggests that if avascular necrosis develops following closed reduction of a congenitally dislocated hip, attempts should be made to prevent lateral and proximal subluxation of the femoral head and to correct thse abnormalities, if possible, once they occur.