BAD CLINICAL-RESULTS OF CEMENTED METAL-BA CKED ACETABULAR COMPONENTS - A 21 MONTH FOLLOW-UP REVIEW OF 124 CASES

Purpose of the study The authors reviewed with short term follow-up 12 4 total hip arthroplasties using a cemented metal-backed acetabular co mponent. The purpose of the study was to evaluate clinical and radiolo gical results because of early periacetabular radiolucent lines report ed by Ritter. Material and methods Surgical procedures were performed in 1988 and 1989 with Saint-Antoine prosthesis (PSA(TM)) including cem ented titanium metal-backed socket. Functional results were appreciate d with Postel-Merle d'Aubigne's score. Radiological results were appre ciated using De Lee and Charnley's criterias for radiolucent lines and Yoder's criterias for socket's migrations. We studied correlation bet ween radiolucent line and age, weight, hip disease, associated bone gr aft, socket size and technical errors. Results With short term follow- up (21 months), we found 60,4 per cent hips with a maximal PMA score ( 18) with an average score of 17,5 per cent. We observed 26,4 per cent of complete periacetabular radiolucent lines with 3 sockets loosening with migration. No significant correlation were found between radioluc ent lines and age, weight, hip disease, associated bone graft, socket size, and technical errors. Discussion This periacetabular radiolucent line rate was comparable to the results of the series using such a ce mented metal-backed socket. This rate was clearly higher than the resu lts of others series using cemented polyethylene sockets. These bad re sults were not correlated to those of finite elements analysis. We thi nk that this is due to metal-backed socket excessive rigidity. Conclus ion Because of this high periacetabular radiolucent line rate, despite of finite elements analysis results, we no more use cemented metal-ba cked acetabular socket since 1991.