A Prospective, Randomized Study of Cross-Linked and Non–Cross-Linked Polyethylene for Total Hip Arthroplasty at 10-Year Follow-Up

In 1999, our institution initiated a prospective study to compare the outcome of total hip arthroplasty patients randomized to either non–cross-linked liners or polyethylene liners that were cross-linked with 5.0 Mrad of gamma-irradiation and heat treated to eliminate free radicals. Among 230 randomized THAs, 13 have had reoperations, and 31 patients with 32 THAs died with less than 9-year follow-up. Follow-up for the remaining 185 THAs averaged 10.0 ± 1.8 years. There have been 9 wear-related liner exchanges among the non–cross-linked group and none among the cross-linked group. Using revision for wear-related complications as an endpoint, survivorship at 10-years was 94.7 ± 4.6% for non–cross-linked and 100% for cross-linked (P = .003). Among unrevised hips, the mean linear wear rate was 0.22 mm/yr for non–cross-linked and 0.04 mm/yr for cross-linked (P < .001). The incidence of clinically important osteolysis with an area of at least 1.5 square centimeters among unrevised hips was 22% for non–cross-linked and 0% for cross-linked (P < .001).