Mid-term Results of Oxford Phase 3 Unicompartmental Knee Arthroplasties at a Small-Volume Center

Abstract

Background and Aims: Unicompartmental knee arthroplasty is considered as an alternative to total knee arthroplasty for patients who have osteoarthritis limited to the medial compartment of the knee. The aim of this retrospective study was to find out clinical and radiological outcomes and related complications using the Oxford phase 3 prosthesis at a small-volume center. Material and methods: In all, 95 Oxford unicompartmental knee arthroplasties (87 patients) were performed between 2000 and 2010 in North Karelia Central Hospital. Of these, five patients had undergone revision surgery. In all, 52 unicompartmental knee arthroplasties (46 patients) participated in this study. The mean age of patients was 61.4 years, and 78.2% of patients were females. Pain and function levels were evaluated by using the Knee Society score. Radiographic analyses were performed on preoperative and postoperative and follow-up radiographs. Results and Conclusions: The mean follow-up time was 6.5 years, and the Kaplan–Meier estimated 9-year implant survival rate was 88.9% (95% confidence interval = 78.7%–99.1%). The median Knee Society score of 77 (range: 18–93) at follow-up was considered good (range: 70–79). In this study, we found out that medial knee pain remains in 10% of unicompartmental knee arthroplasties several years after surgery, although the reason for the pain remained unclear. These mid-term results are promising, and good results can be achieved also at a small-volume center when strict patient selection is followed.