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Journal of Bone and Joint Surgery - British Volume, Vol 87-B, Issue 11,
1493-1497.
doi: 10.1302/0301-620X.87B11.16325 Copyright © 2005 by British Editorial Society of Bone and Joint Surgery Ten-year in vivo wear measurement of a fully congruent mobile bearing unicompartmental knee arthroplastyA. J. Price, DPhil, FRCS(Orth), Clinical Lecturer & Honorary Consultant Orthopaedic Surgeon1; A. Short, DPhil, Research Engineer1; C. Kellett, FRCS, Specialist Registrar1; D. Beard, DPhil, University Research Lecturer1; H. Gill, DPhil, University Research Lecturer1; H. Pandit, FRCS(Orth), Research Fellow1; C. A. F. Dodd, FRCS, Consultant Orthopaedic Surgeon1; and D. W. Murray, MD, FRCS(Orth), Professor, Orthopaedic Surgery11 Nuffield Orthopaedic Centre, Windmill Road, Headington, Oxford OX3 7LD, UK. Correspondence should be sent to Mr A. J. Price; e-mail: andrew.price{at}ndos.ox.ac.uk
Polyethylene particulate wear debris continues to be implicated in the aetiology of aseptic loosening following knee arthroplasty. The Oxford unicompartmental knee arthroplasty employs a spherical femoral component and a fully congruous meniscal bearing to increase contact area and theoretically reduce the potential for polyethylene wear. This study measures the in vivo ten-year linear wear of the device, using a roentgenstereophotogrammetric technique. In this in vivo study, seven medial Oxford unicompartmental prostheses, which had been implanted ten years previously were studied. Stereo pairs of radiographs were acquired for each patient and the films were analysed using a roentgen stereophotogrammetric analysis calibration and a computer-aided design model silhouette-fitting technique. Penetration of the femoral component into the original volume of the bearing was our estimate of linear wear. In addition, eight control patients were examined less than three weeks post-insertion of an Oxford prosthesis, where no wear would be expected. The control group showed no measured wear and suggested a system accuracy of 0.1 mm. At ten years, the mean linear wear rate was 0.02 mm/year. The results from this in vivo study confirm that the device has low ten-year linear wear in clinical practice. This may offer the device a survival advantage in the long term. This article has been cited by other articles:
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