[Acetabulum without cement. Short-term results of a series of 112 threaded cups]

Between January 1982 and December 1987 we used 112 threaded acetabular cups in 102 patients undergoing total hip replacement. The clinical and radiographic results of 107 implants are reported in this survey. Using the functional grading of the hip advocated by Merle d'Aubigné and Postel, 62% can be classified as excellent, very good or good. On x-ray only 35% of the cups show neither radiolucency at the bone-implant interface nor migration of the component. There is a statistically significant correlation between a radiolucency in 2 of the 3 areas at the bone-implant interface and the clinical result. The revision rate for failure of the cup is 11.6% (13 implants). The actuarial survival of the threaded cup decreased from 0.95 in the 1st year to 0.75 in the 5th year after implantation. Analysis of our failures and of published data suggest that the problem lies in the lack of primary bone integration. We describe our difficulties in assessing risk factors, in interpreting the radiographs and in the intraoperative determination of component instability. The disappointing short term results have prompted us to abandon the use of threaded cups.