This study reviewed at skeletal maturity 180 congenitally dislocated, subluxed, and dysplastic hips in 122 patients treated by the same surgeon by using Salter's innominate osteotomy (IO). The mean follow-up was 12 years. The sex of the patient, the laterality and height of the dislocation, the pre-operative acetabular angle, the amount of femoral antetorsion, or the development of postoperative complications (except avascular necrosis of the femoral head), or a combination of these were not found to have a significant influence on the result. However, those patients who had a previous unsuccessful treatment of the hip, who developed pre- or postoperative avascular necrosis, who were unable to be restored by the osteotomy to a normal acetabular angle, or who required an open reduction of the hip joint(or who had a combination of these) were more likely to have an abnormal result. An important finding was that patients who underwent IO before age 4 years were the most likely candidates to receive a very satisfactory result.