Physical Function Following Total Knee Arthroplasty for Osteoarthritis: A Longitudinal Systematic Review With Meta-analysis

OBJECTIVES: To explore the extent of functional improvement following primary total knee arthroplasty for knee osteoarthritis and to compare the trajectories of self-reported and performance-based measures of physical function. DESIGN: Longitudinal systematic review with meta-analysis METHODS: We searched 3 electronic databases from January 2005 to February 2023 for longitudinal cohort studies involving adults with knee osteoarthritis undergoing primary total knee arthroplasty. Estimates of self-reported and performance-based physical function were extracted presurgery and up to 5 years postsurgery. Risk of bias was assessed using a 6-item checklist. Self-reported function scores were converted to a 0-100 scale (higher scores indicate worse function). Mixed models provided pooled estimates after excluding low-quality studies. RESULTS: Out of 230 relevant studies, 72 (n = 19 063) of high quality were included in meta-analyses. Self-reported function significantly improved from presurgery (55.6/100; 95% confidence interval [CI], 53.1 to 58.1) to 3-6 months postsurgery (21.1; 95% CI, 17.9 to 24.3; P<.001). A small decline in self-reported function occurred at 6-12 months (31.0; 95% CI, 25.8 to 36.2; P<.001), with no further change at 12-24 months (30.9; 95% CI, 23.2 to 38.6; P = .919). Performance-based measures exhibited variable trajectories, with most estimates indicating no clinically meaningful improvement following total knee arthroplasty. CONCLUSION: Total knee arthroplasty resulted in clinically meaningful improvements in self-reported function at 3-6 months postoperatively. There was some deterioration in function after 6 months, and at no other time point did the estimate reach a clinically important change. There was limited evidence of clinically meaningful improvements in performance-based measures of physical function at any time point. J Orthop Sports Phys Ther 2025;55(1):1-11. Epub 26 November 2024. doi:10.2519/jospt.2024.12570.