Unicompartmental Knee Arthroplasty Offers More Natural Feeling Joints Compared with Total Knee Arthroplasty: A Systematic Review and Meta-Analysis.

Abstract

Background: Unicompartmental knee arthroplasty (UKA) preserves healthy cartilage and may provide a more "natural-feeling" joint compared with total knee arthroplasty (TKA). The Forgotten Joint Score (FJS) is increasingly used to assess joint awareness. We aimed to systematically compare FJS outcomes in patients undergoing UKA versus TKA.

Methods: Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we searched PubMed, Embase, Scopus, and Web of Science. We included studies reporting FJS in UKA vs. TKA, assessed risk of bias using the Newcastle-Ottawa Scale, and Cochrane RoB-2, and conducted random-effects meta-analyses to calculate pooled mean differences (MD), and sensitivity analyses were performed to assess the robustness of the findings.

Results: Ninteen studies (16 cohort, 3 randomized clinical trials; 4,500 knees) were included. Overall, the pooled MD in FJS favored UKA by 8.45 points (95% CI: 6.03-10.88; p < 0.001), indicating lower joint awareness. However, heterogeneity was high (I² = 96.24%) and publication bias was detected. Sensitivity analyses, including a leave-one-out analysis and an analysis restricted to randomized controlled trials, confirmed the consistency of the results, with no single study disproportionately influencing the findings.

Conclusion: Despite substantial heterogeneity, these findings suggest that UKA may offer superior joint awareness compared with TKA.

Level of evidence: Level III. See Instructions for Authors for a complete description of levels of evidence.