While crosslinking has proven to substantially reduce polyethylene wear during the first decade in vivo, characterizing the long-term clinical performance of Marathon polyethylene remains important because crosslinking is accompanied by a reduction in the ultimate tensile strength, fatigue strength, and elongation to failure of ultra high molecular weight polyethylene. As a consequence, concerns have been expressed about the potential for the liner fracture, in vivo polyethylene oxidation or accelerated wear at long-term follow-up, the effects of femoral head roughening over time and the bioreactivity of crosslinked polyethylene debris particles. Ultimately, the best way to address these concerns is in the context of well-controlled, long-term clinical outcome studies. This study will evaluate outcome at a minimum of 14-years after surgery among the same group of patients whose outcome was previously reported at 10-year follow-up. As part of our efforts to follow patients throughout their lives to obtain long-term outcome data, we will continue to obtain routine follow-up every 5 years from the date of the patient's primary total hip arthroplasty for the duration of the patient's life or until revision of the polyethylene liner (estimated to be 25 years). Because we anticipate that the reduced incidence of wear and osteolysis will result in a lower incidence of revision surgery among the patients randomized to Marathon liners, implant revision for reasons related to wear will be our primary outcome measure at long-term follow-up.