Secondary Avascular Necrosis After Treatment for Congenital Dislocation of the Hip

We made a radiographie study of 104 unilateral congenital dislocations of the hip (CDH) that had an average age of 12 months (range 4–24), were treated with the same therapeutic protocol, and had an average six years follow-up (range 3–13). Radiographie changes were evident in the proximal femoral epiphysis in 57 hips (55%). In 7 (7%) the changes consisted of central osteoporosis with a cystic aspect, without metaphyseal or physeal changes, and had a normal end result without sequelae. This group was classified as type I. Fifty hips (48%) that were type II showed epiphyseal changes consisting of trabecular rarefaction with osteoporosis and irregular sclerosis, followed by a decrease of epiphyseal height and trabecular recovery. Forty-two hips (40%) were type IIA, with 75% decrease of epiphyseal height, 8 cases (8%) had a final physeal lesion.