POLYETHYLENE SOCKETS AND ALUMINA CERAMIC HEADS IN CEMENTED TOTAL HIP-ARTHROPLASTY - A 10-YEAR STUDY

From 1981 to 1983, we implanted Bioceram type-4 and type-5 prostheses in 61 hips in 54 patients with osteoarthritis secondary to acetabular dysplasia, congenital subluxation, or congenital dislocation of the hi p, Fifty-seven hips in 50 patients were followed for a mean of 11.1 ye ars (10 to 13), The mean age of the patients at operation was 53 years (31 to 70), Functional evaluation using the Merle d'Aubigne and Poste l hip score showed a 77% success rate. Radiological loosening occurred in three femoral (5%) and 16 acetabular components (28%), Autologous femoral head grafts were used in 18 hips and became incorporated, givi ng mechanical support to the socket except for one which occupied a la rge weight-bearing area and eventually collapsed. The mean polyethylen e wear was 1.1 mm (0 to 3.6) and the mean wear rate was 0.10 mm/year ( 0 to 0.31), A high rate of wear correlated with calcar resorption (p > 0.002) but not with acetabular loosening, There was no breakage of a ceramic head, Study of the ceramic heads and polyethylene sockets retr ieved after ten years showed excellent surface roughness, sphericity, and bending strength for the heads but scratches and voids were seen o n the sockets.