Acetabular reconstruction in developmental hip dysplasia using reinforcement ring with a hook.

We followed prospectively 27 patients with severe acetabular bone-stock deficiencies due to developmental dysplasia of the hip. Mean preoperative patient age was 56 (34-78) years, mean Harris hip score was 31 (16-66) points and pre-operative mean acetabular angle of Sharp was 47 degrees (34 degrees - 61 degrees). Operative acetabular reconstruction was performed in 28 hips using reinforcement ring with a hook placed in the true acetabulum and autologous bone grafting. A 2-year clinical and radiological follow-up was available in 27 hips. Mean Harris hip score improved to 91 (70-100) points. There were no clinical or radiological signs of aseptic loosening in 25 hips, and the bone graft was radiologically incorporated in all hips. In 24 hips, a radiostereometric analysis showed low rates of non-progressive translation and rotation in 21 reinforcement rings. Three rings showed progressive translation and/or rotation at the 2-year follow-up and were rated probably loose.