USE OF CEMENTED ALL-POLYETHYLENE AND METAL-BACKED ACETABULAR COMPONENTS IN TOTAL HIP-ARTHROPLASTY - A COMPARATIVE-STUDY

The results of 115 primary total hip arthroplasties (97 patients) perf ormed using the Charnley system and contemporary cementing techniques were reviewed. Fifty-five all-polyethylene cups and 60 metal-backed cu ps were used. The mean follow-up period was 84 months. No statisticall y significant difference was noted between groups for radiographic loo sening and no cup has been revised to date. Survival analysis did not reveal a statistically significant difference between groups. Although all-polyethylene cups had significantly greater polyethylene thicknes s, no difference was noted for rate of wear. Increased loosening of th e metal-backed cups was not observed. Polyethylene thickness is increa sed by the use of 22-mm heads and this may have accounted for the lack of difference in loosening rates of the all-polyethylene and metal-ba cked cups.