A Randomized Prospective Evaluation of Outcomes After Total Hip Arthroplasty Using Cross-linked Marathon and Non–cross-linked Enduron Polyethylene Liners

Cross-linked liners were introduced with the promise that they would substantially reduce polyethylene wear. In 1999, our institution initiated a prospective study to compare the outcome of total hip arthroplasty patients who were randomized to non–cross-linked Enduron liners with that of total hip arthroplasty patients who were randomized to Marathon polyethylene liners that had been cross-linked with 5 Mrad (50 kGy) of gamma-irradiation and heat-treated to eliminate free radicals. At a mean follow-up of 5.7 years, the clinical outcomes among the Marathon and Enduron liners were similar. However, the mean wear rate was 0.01 ± 0.07 mm/y for the Marathon group, which represents a 95% reduction compared with the mean wear rate of 0.19 ± 0.12 mm/y for the Enduron group. In addition, the incidence of osteolysis was lower in the Marathon group.