Original Article 10-Year Follow-Up Wear Analysis of Marathon Highly Cross-Linked Polyethylene in Primary Total Hip Arthroplasty Jared S. Bookman, MD, Ian D. Kaye, MD, Kevin K. Chen, MA, Fredrick F. Jaffe, MD, Ran Schwarzkopf, MD, MSc * Department of Orthopaedic Surgery, NYU Langone Medical Center's Hospital for Joint Diseases, New York, New York article info Article history: Received 29 November 2016 Received in revised form 20 February 2017 Accepted 7 March 2017 Available online xxx Level of Evidence: 4 Keywords: total hip arthroplasty highly cross-linked polyethylene wear analysis 10-year follow-up Marathon liner abstract Background: Short-term and intermediate-term wear rates for highly cross-linked polyethylene (HCLPE) liners in total hip arthroplasty (THA) are significantly lower than published rates for traditional polyethylene liners. The aim of this study was to report the longest-to-date follow-up of a specific HCLPE liner. Methods: A series of 35 THAs using a specific HCLPE liner were reviewed. Anteroposterior radiographs were reviewed for femoral head penetration, the presence of femoral and/or acetabular osteolysis, long-term survival, total wear, and wear rates in all patients. Results: The average patient age at time of surgery was 70 years with an average follow-up of 10 years (118 months; range, 7.2-13.4 years). The mean wear rate in our cohort was 0.07 mm/y. Total wear was 0.71 mm over the study period. No hips showed evidence of osteolysis in any zones. Survivorship at latest follow-up was 100% with all-cause revision as an end point. Conclusion: The wear rate of HCLPE liners continues to be lower than published wear rates for traditional polyethylene and continues to reaffirm the acceptably low wear rates using HCLPE acetabular liner in primary THA. © 2017 Elsevier Inc. All rights reserved. Wear-associated osteolysis is a long-term problem associated with traditional polyethylene liners in total hip arthroplasty (THA) [1e3]. These wear particles can cause an inflammatory response leading to aseptic loosening and ultimately hip instability necessitating revision surgery [2,4,5]. Highly cross-linked poly- ethylene (HCLPE) acetabular liners were developed in an effort to reduce polyethylene wear and osteolysis, thus increasing long-term survival of THA implants [6e9]. Multiple in vitro and in vivo wear studies have shown that HCLPE acetabular liners wear at a signif- icantly slower rate than traditional polyethylene [7,10e12]. Polyethylene cross-linking is accomplished by a gamma irradia- tion process, inducing free radical and covalent bond formation. Thermal stabilization is then required to reduce free radicals, which involves either melting or annealing [8,9]. Annealing refers to heating the polyethylene to a temperature somewhat below the melting point, to avoid the reduction of crystallinity that occurs with melting [13]. Annealing, however, is less effective than melting in extin- guishing free radicals that may lead to long-term oxidative degra- dation [14]. Furthermore, each HCLPE acetabular liner has a different manufacturing process and should be evaluated individually [10,15]. In vivo clinical studies with short-term and intermediate-term follow-up have shown decreased wear and excellent results with several HCLPE liners [12,16]. This study focused on the in vivo wear rates of a specific acetabular liner, Marathon (Marathon, DePuy, a Johnson and Johnson Company, Warsaw, IN), which was approved by the FDA in 2000. Although there have been some studies looking at short-term and intermediate-term follow-ups in patients using Marathon liners, there has been minimal long-term follow-up in this same patient population [6,16e18]. As the goal of HCLPE acetabular liners is to reduce wear rates and ultimately increase implant longevity, it is essential that efficacy is measured at a long-term follow-up to truly evaluate the utility of these liners. Our Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to http://dx.doi.org/10.1016/j.arth.2017.03.016. * Reprint requests: Ran Schwarzkopf, MD, MSc, Department of Orthopaedic Surgery, NYU Langone Medical Center, NYU Hospital for Joint Diseases, 301 E.17th Street, New York, NY 10003. Contents lists available at ScienceDirect The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org http://dx.doi.org/10.1016/j.arth.2017.03.016 0883-5403/© 2017 Elsevier Inc. All rights reserved. The Journal of Arthroplasty xxx (2017) 1e3