Ceramic femoral heads have superior scratch resistant with better wettability and improved wear characteristics compared to metal heads in the laboratory setting. The objective of this study was to compare long-term in vivo wear rates of ceramic and metal femoral heads against conventional polyethylene articulation with cementless stems in young, active patients. Thirty-one matched pair of alumina and metal (Cr-Co) femoral heads against conventional polyethylene in young patients (between 45 and 65 years old) were analyzed for wear and failures for mechanical reasons. The match was based on gender and age at the time of surgery. All procedures were performed between June 1989 and May 1992 by a single surgeon via posterolateral approach, using cementless RB (Ranawat-Bernstein) stems, HG II (Harris-Galante) cups, 4150 conventional polyethylene and 28 mm femoral heads. Hospital for Special Surgery (HSS) hip score was used for clinical analysis. Wear measurements were performed between the initial anteroposterior standing pelvis radiographs, at a minimum of one year after the index procedure to eliminate the effect of bedding-in period, and the latest follow-up. Two independent observers analyzed polyethylene wear rates using the computer-assisted Roman 1.70 software. In revision cases, the wear rates were calculated from radiographs prior to revision surgery. A pair student t test was performed to analyze the statistical difference. Two-tailed ρ values less than 0.05 were considered statistically significant.Introduction
Materials and Methods
