Abstract
Aim: unicompartmental Knee Arthroplasty (UKA) is experiencing a resurgence in popularity. In order to provide accurate indications for UKA it is essential to evaluate the long-term results and to determine which patients are appropriate candidates.
Methods: One hundred and seventeen cemented UKA were performed between 1988 and 1995 in 90 patients with osteoarthrosis. The cohort comprised 25 Brigham (BG) and 92 Miller-Galante (MG) implants performed in a sequential fashion in well-matched groups. The average age at the time of the surgery was 66.4 years (range: 39.5 years to 87.1 years). There were 72 males and 45 females. The surgery was performed by either one of two surgeons. The minimum follow-up period was five years and the maximum was 13.2 years. Data, including KSCRS scores and radiographic results, were collected prospectively for all patients.
Results: Six Patients died during the study period and two were lost to follow-up. The average time of death was eight years post-operatively, with average latest KSCRS prior to death of 184 points compared with 134.7 pre-operatively. Twelve knees were revised at an average of 4.25 years (range 1.0 – 11.8 years) after the initial surgery, with polyethylene wear and progression of arthrosis being the most common reasons. The surviving 97 implants had an average follow-up of 9.6 years, with an average KSCRS improving from 100 points pre-operatively to 172 points at latest follow-up. There was no radiographic evidence of prosthetic loosening. A survival analysis using revision as the end-point (Kaplan-Meier, 95% confidence interval) showed a 10 year survival of 89% for all prostheses, 85% for BG, and 90% for MG prostheses.
Conclusions: Relatively few reports of the long-term results of UKA are available. The results of this study are slightly inferior but still comparable to TKA after the same follow-up period, suggesting that, with proper patient selection, UKA can offer reliable relief of pain and restoration of function for patients with unicompartmental knee osteoarthrosis.
The abstracts were prepared by Professor A. J. Thurston. Correspondence should be addressed to him at the Department of Surgery, Wellington School of Medicine, PO Box 7343, Wellington South, New Zealand
