To examine the acetabular development after the surgical treatment of a developmental dislocation of the hip (DDH).

The serial radiographs of 27 hips were evaluated. The measurement included: acetabular index, CE angle, Smith's h/b, c/b ratio, medial joint space, and center-head distance discrepancy (CHDD). All the patients were followed up until they were at least 10 years old. The overall results were evaluated using the modified Severins classification (group I & II, satisfactory; group III & IV, unsatisfactory).

In the satisfactory group, the average acetabular index at 1 and 3 years after the pelvic osteotomy was <25 degrees. In the satisfactory group, the average CHDD 1 and 3 years after surgery was <6%. Eighty-two percent of hips with a CHDD <6% at postoperative 1 and 3 years were in the satisfactory group, whereas 81% of hips with CHDD >6% were in the unsatisfactory group.

The most reliable factors for predicting normal acetabular development after surgery were an acetabular index <25 degrees and a CHDD <6%. If the hips do not meet the criterion of a CHDD <6% after the osteotomy of one component (either the pelvic or femur) then the other component must be osteotomized.