We reviewed the outcome of a new radical operation of seventeen congenitally dislocated hips in fifteen children, and six residual subluxation of the hips in six children. The follow-up duration ranged from one year and one month to ten years and seven months. The mean age at the time of operation was eleven months (range; nine months to twenty five months). The acetabular angle, the center-edge angle of Wiberg and the distance “a” “b” of Yamamuro were measured on the roentogenograms before the open reduction and at the time of final follow-up. The mean ace tabular angle before operation was 38° and 31° at the time of follow-up. The mean center-edge angle was improved from -42° to 14°, the mean distance “a” from 2mm to 9mm, and the mean distance “b” from 17mm to 9mm. No avascular necrosis of the femoral head occurred after this operation. Two secondary operations were performed for the residual acetabular dysplasia of the hips. This operation involves two important procedures unlike other approaches. One is circumferential capsulotomy and dividing the piriformis to pull down the femoral head in front of the acetabulum. Another procedure is the resection of the whole transverse ligament to open the acetabular entrance to sink the head into the acetabulum deeply. This procedure reffered to as the wide exposure method, is useful for troublesome dislocated hips.
