Abstract
PURPOSE: Unicompartmental knee arthroplasty (UKA) is a widely used treatment for isolated compartmental knee osteoarthritis, especially in younger and more active patients. Return to sport (RTS) has become a key postoperative outcome. While RTS after UKA is generally favourable, the influence of factors such as implant design, surgical technique, compartment treated and patient characteristics remains unclear. An updated and granular synthesis is needed, particularly to allow direct comparison with RTS outcomes after total knee arthroplasty (TKA). METHODS: A systematic review and meta-analysis was conducted following PRISMA guidelines and registered on PROSPERO. PubMed, Embase and Scopus were searched for studies from 2016 to April 2025 reporting RTS outcomes after UKA. Two reviewers independently screened articles, extracted data and assessed methodological quality using the modified Coleman Methodology Score. Weighted means and proportions were calculated, and correlation analyses explored associations between RTS and patient and surgical variables. RESULTS: Thirteen studies (n = 1675 patients) were included. The overall weighted mean RTS rate after UKA was 87.97% with a substantial proportion of patients resuming intermediate and high-impact sports. No significant differences in RTS were found between fixed-bearing and mobile-bearing implants, or between medial and lateral UKA. RTS was comparable between robotic-assisted and standard techniques. A moderate negative correlation between BMI and RTS was observed (r = -0.69, p = 0.019). Compared to TKA, UKA patients have a higher RTS rate (87.97% vs. 72%). UKA patients resumed a broader range of sports, with increased participation in intermediate- and high-impact activities. CONCLUSIONS: UKA offers high RTS rates and supports participation in demanding physical activities. Neither implant design nor surgical technique substantially impacts RTS, whereas patient-related factors, especially BMI, are key predictors. Compared to TKA, UKA is associated with superior sport-related outcomes, underscoring its role in appropriately selected patients. These findings support shared decision-making and personalised postoperative planning. LEVEL OF EVIDENCE: Level III.