Porous-coated cementless acetabular cups in revision surgery: a 6- to 11-year follow-up study.

Between 1986 and 1991, 65 cementless hemispherical acetabular cups were implanted in 60 patients in revision surgery. Different designs were used, including PCA (29 cups), Duraloc (14 cups), Harris-Galante (12 cups), and Omnifit (10 cups). The mean age of patients was 54.7 years. The Paprosky types of the acetabular tone defects were type 1, 2 hips; type 2, 38 hips; type 3A, 15 hips; and type 3B, 10 hips. For unrevised hips, the mean follow-up was 8.3 years (range, 6-11 years). Bone allografts were used in 56 hips: Morcellized cancellous graft was used in 42 hips, structural graft for contained defects was used in 7 hips, and structural graft for uncontained defects was used in 7 hips. There were poor clinical results in 14 hips (22%). Re-revision was necessary in 7 hips (10.8%). There was definite radiographic loosening in 18 hips and possible loosening in 4 hips. Screw failure occurred in 6 hips, and a radiolucency in 1 or more DeLee-Charnley zones was apparent in 45 hips (69.2%). Moderate or severe graft resorption were found in 4 of the 42 morcellized grafts, in 6 of the 7 structural grafts for uncontained defects, and in all 7 of the 7 structural grafts for contained defects. The best results were obtained in hips with a bone defect of less than 30%. The use of a cementless acetabular cup supplemented with screws is contraindicated in hips with a bone defect greater than 50%. Hip reconstruction using structural bone-graft to stabilize the prosthesis gives the worst results.