Outcomes of modified Dega acetabuloplasty in acetabular dysplasia related to developmental dislocation of the hip.

UNLABELLED: Developmental dislocation of the hip (DDH) is frequently, even after reduction, associated with residual acetabular dysplasia. Various surgical techniques are used to correct this, one of which is Dega acetabuloplasty. This osteotomy technique has, however, rarely been assessed in this particular indication. The present study therefore sought to describe the technical details, report clinical and radiological results, and present limitations.

HYPOTHESIS: Unlike reorientation osteotomy in children, Dega acetabuloplasty does not lead to a high rate of acetabular retroversion at the end of growth.

PATIENTS AND

METHODS

Sixteen Dega acetabuloplasties in 15 patients were assessed on joint range of motion, limp, lower limb length discrepancy and impaired everyday activity, pre-operatively and at end of follow-up. Hips were classified following Wicart et al. (2003). Radiologic assessment comprised Wiberg angle and acetabular index, pre- and post-operatively and at follow-up. Acetabular retroversion was analyzed by crossover sign, and hips were classified following Severin.

RESULTS

Median age at surgery was 3 years (range, 1.1-12.2 years) and 10 years (6.4-17.8) at end of follow-up. At end of follow-up, all hips were pain-free and classified as Wicart A, and all activities were allowed. Radiologically, hips were classified as Severin I, II or IV, in 11 (68.5%), 4 (25%) and 1 (6.5%) cases respectively. Wiberg angle rose from a mean 3.3° (-30° to 30°) to 23° (10° to 38°) and acetabular index fell from a mean 31° (25° to 45°) to 20° (5° to 30°) with surgery, and both continued to improve over follow-up: 26° (12-45°) and 13° (3-24°) respectively (P<0.05). Acetabular retroversion was found in 2 of the 10 hips with Y cartilage fusion.

DISCUSSION: Modified Dega acetabuloplasty was effective in correcting acetabular dysplasia in DDH. Functional and radiological results were good, with a low rate of acetabular retroversion (2/10), unlike with other techniques.

LEVEL OF EVIDENCE: Level IV. Therapeutic study.