Minimum 5-Year Wear Analysis of First-Generation Highly Cross-Linked Polyethylene in Patients 65 Years and Younger Amar S. Ranawat, MD,* Panagiotis Tsailis, MD,* Morteza Meftah, MD, y Trevor W. Koob, BA,* Jose A. Rodriguez, MD, z and Chitranjan S. Ranawat, MD* Abstract: The purpose of this study was to analyze wear rates of highly cross-linked polyethylene comparing the Martell and the Roman methods in 112 total hip arthroplasties in patients 65 years and younger, with a mean follow-up of 5.7 years. The mean wear rates in the Martell and Roman methods were 0.014 ± 0.05 mm/y and 0.011 ± 0.04 mm/y when including all values and 0.043 ± 0.028 mm/y and 0.038 ± 0.02 mm/y when negative values were assumed to be zero, respectively. Both Roman and Martell methods showed similar low wear rates with negative values. The Roman method had higher precision and was more user friendly because it required less steps to measure wear, especially when comparing with the manual feature of Martell method. Keywords: total hip replacement, highly cross-linked polyethylene, Martell hip analysis, Roman software, wear rates. © 2012 Elsevier Inc. All rights reserved. The use of highly cross-linked polyethylene (HCLPE) has become the bearing of choice in most total hip arthroplasties being performed today [1]. This trend is due to the excellent wear properties of HCLPE, its durability, and its forgiveness [1,2]. Reduction of HCLPE wear compared with conventional polyethylene (PE) has been demonstrated in hip simulator studies [3,4]. Several reports have also demonstrated the clinical wear reduction of HCLPE after total hip arthroplasty [5-8], but there is no study investigating wear of HCLPE in patients 65 years and younger. Most of the published wear studies use the computer- assisted Hip Analysis Suite method described by Martell and Berdia [9] for assessing femoral head penetration. One difficulty in interpretation of data using the Martell method is the presence of negative wear values [9-11]. This phenomenon is speculated to be due to slight radiographic distortions of the femoral head and/or the acetabular component or by blurred edges on some clinical radiographs [1]. Another way to detect wear rates is by the Livermore method using Roman software [12], which is freely available software [13] that uses a best-fit algorithm to determine a circle with a center from any number of user-determined points. In a recent study comparing computer-based analysis of PE wear, the Roman method was shown to be more precise, easier to use, and less expensive than the Martell method [12]. The aim of this study was to evaluate the in vivo wear rates of Crossfire HCLPE, comparing the Martell and the Roman methods, at a minimum of 5 years of follow up in patients 65 years old and younger. Materials and Methods A total of 112 near-consecutive, primary noncemen- ted total hip arthroplasties in 91 patients with age of 65 years and younger were identified from our institu- tional review board–approved prospective database. Patients were excluded based on refusal to participate in the study. The operations were performed between 1999 and 2002, with a mean follow-up of 5.7 years (range, 5-7.7 years). All the operations were performed by 1 of 3 surgeons (JAR, ASR, and CSR). There were 57 male and 34 female patients. The mean age was 52.2 years (20.7-65 years). The diagnosis was osteoar- thritis in 97% of patients. All cases were performed using the Osteonics Secur-fit HA PSL acetabular component and the Osteonics Secur- fit or Secur-fit Plus HA femoral component (Stryker Orthopaedics, Mahwah, NJ). Ninety-five acetabular From the *Weill Medical College of Cornell University, Hospital for Special Surgery, New York, New York; yRanawat Orthopaedics, Weill Medical College of Cornell University, Hospital for Special Surgery, New York, New York; and zDepartment of Orthopaedics, Lenox Hill Hospital, New York, New York. Submitted August 23, 2010; accepted July 9, 2011. The Conflict of Interest statement associated with this article can be found at doi:10.1016/j.arth.2011.07.003. Reprint requests: Amar S. Ranawat, MD, Hospital for Special Surgery, 535 E. 70th St, New York, NY 1002. © 2012 Elsevier Inc. All rights reserved. 0883-5403/2703-0004$36.00/0 doi:10.1016/j.arth.2011.07.003 354 The Journal of Arthroplasty Vol. 27 No. 3 2012