Abstract
Purpose: Alumina resistance to wear is now well established. In the eighties, improvement in manufacturing processes and implant design led to a significant reduction in the risk of fracture but failure of acetabular fixation remained a cause leading to revision. The purpose of this work was to present our results with a consecutive series of press-fit cementless metal backed alumina-alumina THA implanted between 1990 and 1992 in patients aged less than 55 years.
Material and methods: The series included 62 patients and 71 hips. Mean age at surgery was 46 years (range 21 – 54). A cemented titanium femoral stem with a 32-mm alumina head was implanted with a press-fit metal-backed cup with an alumina insert. Three patients (4 hips) died. Four hips required revision for infection (n=1), unexplained pain (n=1), fracture of the alumina head (n=1), and aseptic cup loosening (n=1). At nine years the survival rate was 93.7% taking revision for all cause as the end point and 98.4% taking revision for aseptic loosening as the end point.
Results: Fifty patients (57 hips) were reviewed with at least five years follow-up (mean 8 years, range 6–11 years). According to the Postel-Merle d’Aubigné score, functional outcome was excellent or very good in 96% of the patients. A minimal partial lucent line was observed around 38% of the cups, mainly in zone III and one cup exhibited a complete line measuring < 1 mm. Isolated osteolysis of the femur was observed in one hip. There was no case with acetabular osteolysis or implant migration.
Discussion: Combining a cemented stem with a pressfit metal backed cup has provided very satisfactory mid-term results in these active patients. Use of a press-fit hemispheric cup has been found to be a reliable fixation method for alumina cups and improves results of Al-AL THA significantly. In light of the excellent resistance of the alumina cups against wear, these results can be expected to continue for a long period.
The abstracts were prepared by Docteur Jean Barthas. Correspondence should be addressed to him at Secrétariat de la Société S.O.F.C.O.T., 56 rue Boissonade, 75014 Paris.
