Wear of ultra-high-molecular-weight polyethylene cup articulating with 22.225 mm zirconia diameter head in cemented total hip arthroplasty

A number of studies have highlighted the increasing incidence of aseptic cup loosening with increasing depth of cup penetration by the metal head. We present our experience with a 22.225 mm diameter zirconia head on a 9-10 taper articulating with an ultra-high-molecular-weight polyethylene (UHMWPE) cup in cemented total hip arthroplasties. We prospectively studied the wear of the UHMWPE cup articulating with a 22.225 mm diameter zirconia head in cemented total hip arthroplasties. A total of 339 patients (153 men, 186 women, 373 hips) were included. The patients' mean age at surgery was 52 years (17-76 years), with 41 % age 50 years or younger. Their mean weight was 72.4 kg (24-125 kg). At a mean follow-up of 4.3 years (0-8 years) the mean penetration rate of the cup was 0.03 mm/year (0-0.51 mm/year). Altogether, 289 (77.5 %) showed no measurable wear, 38 (10.2 %) had a penetration rate of 0.11 mm/year or less, 33 (8.9 %) had a rate of 0.12-0.2 mm/year, and in 13 (3.5 %) the rate was more than 0.2 mm/year. Ceramic-UHMWPE is the next stage in the evolution of total hip arthroplasty for addressing wear and any possible related issues.