Early outcomes of the oxford unicompartmental knee arthroplasty: 140 cases from a single institute in Taiwan

Abstract

Background: The clinical and radiologic outcomes of the Oxford Unicompartmental Knee Arthroplasty utilizing Microplasty® instrumentation have not been extensively investigated in Taiwanese patients. Despite the efficacy of this treatment for unicompartmental knee diseases, its specific impact on this population remains unknown. Methods: We retrospectively analyzed prospectively collected data of patients who underwent OUKA with MP between 2018 and 2021, including demographic information, component position, pre- and postoperative knee range of motion (ROM), numeric rating scale (NRS), and 2011 Knee Society Score–functional activity score (2011 KSS-FAS). We compared pre- and postoperative data and analyzed the correlation between clinical and radiographic outcomes. Results: Among 140 patients with an average age of 66.8 years, predominantly female, the majority exhibited components that fell within the radiographically acceptable tolerance ranges. The mean 2.5-year follow-up revealed significant improvements in knee ROM from 102.6° ± 12.9° to 127.3° ± 9.8° (p < 0.05), pain reduction from 7.7 ± 0.8 to 0.4 ± 0.7 (p < 0.001), and KSS-FAS from 30.7 ± 10.5 to 94.3 ± 5.2 (p < 0.001). Notably, a tibial component medial overhang within tolerance predicted shorter hospital stays, and a higher preoperative KSS correlated with lower postoperative NRS. No independent variables were identified as predictors of a higher postoperative KSS. Conclusion: Our study on OUKA with MP in Taiwanese patients reveals promising early clinical and radiographic outcomes. Tibial component medial overhang <3 mm is associated with shorter hospital stays, and a higher preoperative KSS predicts lower NRS at 1 year postoperatively.