Mid-term Functional Outcomes Following One-stage Single-Sitting Bilateral and Unilateral Unicompartmental Knee Arthroplasty: A 5-year Prospective Cohort Study

Introduction: Unicompartmental knee arthroplasty (UKA) is a joint-preserving surgical option for individuals with isolated medial compartment osteoarthritis (OA). Although performing UKA on both knees in a single sitting can offer logistical benefits, there is limited data comparing its safety and clinical outcomes with unilateral procedures. The objective of this study was to compare the mid-term functional outcomes, recovery parameters, and complication rates between one-stage single-sitting bilateral and unilateral UKA. Materials and Methods: This observational study included 256 patients diagnosed with medial compartment OA who underwent either one-stage single-sitting bilateral UKA (n = 134) or unilateral UKA (n = 122). Functional outcomes were evaluated using the Oxford Knee Score (OKS), pain levels through the Visual Analog Scale (VAS), range of motion (ROM), post-operative satisfaction, and time to return to regular activities over a 5-year follow-up period. Results: Significant improvements in OKS, ROM, and VAS scores were observed in both groups (P < 0.001). Patients undergoing one-stage single-sitting bilateral UKA required fewer physiotherapy sessions (17.6 vs. 21.4, P < 0.001) and returned to daily activities earlier (5.2 vs. 6.4 weeks, P < 0.001), without increased hospital stay or complications. Conclusion: One-stage single-sitting bilateral UKA appears to be a safe and effective treatment strategy for carefully selected patients with medial compartment OA, offering comparable safety and enhanced functional recovery compared to unilateral procedures.