The development of the proximal femur was studied in a follow up of 64 patients--on average 24.4 years of age--with congenital hip dislocation and 101 subsequent aseptic necroses of the femoral head. For measurement of the angle of antetorsion and the femoral neck-shaft angle, biplanar radiographs were taken. A coxa valga with a true femoral neck-shaft of 137 to 164 degrees was present in one third of the cases with partial necrosis and in the group without necrosis. An increasing degree of necrosis led to coxa vara. Damage of the capital epiphysis caused development of coxa vara (average of 115.77 degrees), overgrowth of the greater trochanter and increase of femoral antetorsion (average of 30.23 degrees). Pre-existing damage of the capital epiphysis following non-operative treatment of congenital hip disease or Perthes disease cannot be recommended for intertrochanteric varisation osteotomy.