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° (34°–61°). 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.