A prospective, randomized clinical study comparing marathon and enduron polyethylene acetabular liners: 3 year results

Abstract

In 1999, the authors began a prospective, randomized study to compare the clinical performance of DePuy’s highly crosslinked polyethylene acetabular liner (Marathon) to that of conventional Enduron polyethylene sterilized by gas plasma. Over the course of two years, 236 hips were enrolled in the IRB approved study. At the writing of this abstract, 126 patients had a minimum follow-up of 3 years. For these patients, we used a computer-assisted radiographic technique to measure polyethylene wear rates. At 3.2 years, the mean true wear rate for the Marathon liners was significantly less than that of the non-irradiated Enduron liners (0.12 vs. 0.22 mm/yr).Moreover, a significantly greater percentage of Marathon liners had true wear rates less than 0.1 mm/year than did Enduron liners (62% vs. 22%). These initial clinical data confirm laboratory tests demonstrating a reduction in wear with Marathon polyethylene as compared to non-irradiated Enduron polyethylene. The reduction in mean wear rate was coupled with a significantly greater proportion of low-wearing liners in the Marathon group. Of note, however, at this short follow-up both groups continue to have outliners with large head penetration rates, which tend to inflate the mean wear rate of each population.