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.