The mid-term clinical results of the phase 3 Oxford unicompartmental knee arthroplasty: a 6- to 8-year follow-up

Unicompartmental knee arthroplasty (UKA) is widely performed in the United Kingdom for the management of patients with symptomatic osteoarthritis of the medial compartment of the tibiofemoral joint. A limited number of papers have presented the findings of mid-term clinical and survival data with sufficiently large patient numbers following mobile-bearing UKA. The purpose of this study was to present the 6- to 8-year follow-up data on a series of 230 minimally invasive medial Oxford Phase 3 mobile-bearing UKAs in our institution. Data on surgical procedure, postoperative rehabilitation requirement, complications, revision procedures and Oxford Knee Score (OKS), Short Form-12 (SF-12) and visual analogue scale (VAS) pain scores were analysed. The results indicated that the majority of patient’s recoveries were uneventful, with 96% experiencing no postoperative complications. The mean OKS, VAS pain and SF-12 scores indicated good functional outcomes and acceptable perceived general health for this age group. Twenty-one patients underwent revision surgery, indicating a survival rate of 85% (95% CI: 0.76–0.91) during the 6- to 8-year follow-up period. The most frequently cited indication for revision was due to progression of osteoarthritis to the lateral component. To conclude, this series indicated that the mobile-bearing Oxford UKA provides good clinical outcomes at 6- to 8-year follow-up, with minimal requirement for postoperative rehabilitation, few complications and an acceptable survivorship in the mid-term.