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

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, preoperative and postoperative knee range of motion (ROM), numeric rating scale (NRS), and 2011 Knee Society Score-functional activity score (2011 KSS-FAS). We compared preoperative 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.