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Five-Year Comparison of Oxidized Zirconium and Cobalt-Chromium Femoral Components in Total Knee ArthroplastyA Randomized Controlled Trial
Catherine Hui, MD, FRCS(C)1; Lucy Salmon, BAppSci (Physio), PhD1; Shinichi Maeno, MD, PhD1; Justin Roe, MBBS, FRACS1; William Walsh, PhD2; Leo Pinczewski, MBBS, FRACS1
1 North Sydney Orthopaedic and Sports Medicine Centre, Suite 2, 3 Gilles Street, Wollstonecraft, NSW 2065, Australia. E-mail address for L. Pinczewski: lpinczewski@nsosmc.com.au
2 Surgical and Orthopaedic Research Laboratories, University of New South Wales Prince of Wales Hospital, Randwick, NSW 2031, Australia
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Disclosure: In support of their research for or preparation of this work, one or more of the authors received, in any one year, outside funding or grants in excess of $10,000 from Smith & Nephew. In addition, one or more of the authors or a member of his or her immediate family received, in any one year, payments or other benefits in excess of $10,000 or a commitment or agreement to provide such benefits from a commercial entity (Smith & Nephew).

Investigation performed at the North Sydney Orthopaedic and Sports Medicine Centre, Wollstonecraft, New South Wales, Australia

Copyright © 2011 by The Journal of Bone and Joint Surgery, Inc.
J Bone Joint Surg Am, 2011 Apr 06;93(7):624-630. doi: 10.2106/JBJS.I.01753
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In vitro analysis has shown that oxidized zirconium on ultra-high molecular weight polyethylene has better wear properties than cobalt-chromium on ultra-high molecular weight polyethylene. The purpose of this study was to determine if oxidized zirconium femoral components performed better than cobalt-chromium in vivo and if the use of oxidized zirconium components had clinical adverse effects.


Forty consecutive patients (eighty knees) underwent simultaneous bilateral cruciate-retaining total knee arthroplasty for primary osteoarthritis from January 2002 to December 2003. For each patient, the knees were randomized to receive the oxidized zirconium femoral component, with the contralateral knee receiving the cobalt-chromium component. Outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index, Knee Injury and Osteoarthritis Outcome Score, Knee Society score, and British Orthopaedic Association patient satisfaction scale. Radiographic outcomes include the Knee Society total knee arthroplasty roentgenographic evaluation and scoring system and measurement of radiographic wear. Patients and assessors were blinded to the treatment groups and results.


There were no significant differences in clinical, subjective, and radiographic outcomes between the two implants at five days, six weeks, and one, two, or five years postoperatively. At five years following surgery, 38% of the patients preferred the cobalt-chromium knee compared with 18% who preferred the oxidized zirconium knee (p = 0.02) and 44% had no preference.


Five-year outcomes after total knee arthroplasty with oxidized zirconium and cobalt-chromium femoral components showed no significant differences in clinical, subjective, and radiographic outcomes. Patients had no preference or preferred the cobalt-chromium prosthesis to the oxidized zirconium prosthesis at the time of the five-year follow-up. There were no adverse effects associated with the use of oxidized zirconium femoral implants.

Level of Evidence: 

Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence.

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    These activities have been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint sponsorship of the American Academy of Orthopaedic Surgeons and The Journal of Bone and Joint Surgery, Inc. The American Academy of Orthopaedic Surgeons is accredited by the ACCME to provide continuing medical education for physicians.
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