Abstract
OBJECTIVES: Whether high-intensity exercise can effectively improve the symptoms and quality of life of patients with knee osteoarthritis has not been determined. This study updates the evidence on the efficacy of high-intensity training for patients with knee osteoarthritis by integrating all large-scale randomized controlled trials (RCTs). METHODS: A systematic literature search was conducted in PubMed, Embase, Web of Science, and Cochrane through November 2024. Outcomes assessed included Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), 6-min walk test (6-MWT), knee flexion strength, knee extension strength, leg press strength, Knee Injury and Osteoarthritis Outcome Score (KOOS) (pain, symptoms, and QoL), stair climbing test, and timed-up-and-go (TUG). Standardized mean differences (SMD) with 95% confidence intervals (CI) were used to pool continuous variables. Sensitivity analysis was performed to assess result stability. Analyses were conducted using Review Manager 5.4 and STATA 15.1. RESULTS: Nine RCTs with 1,540 patients were included. The average age of the patients ranged from 59.1 to 69 years. Meta-analysis showed significant improvements in knee flexion strength (SMD: 0.39; 95% CI: 0.08, 0.70), leg press strength (SMD: 0.47; 95% CI: 0.23, 0.70), KOOS symptoms (SMD: 0.18; 95% CI: 0.02, 0.35), and KOOS QoL (SMD: 0.29; 95% CI: 0.13, 0.45) in the high-intensity exercise group compared to the control. However, high-intensity exercise had no significant effect on WOMAC, 6-MWT, knee extension strength, KOOS pain, stair climbing, or TUG. CONCLUSION: High-intensity exercise significantly improves knee flexion strength, leg press strength, and KOOS symptoms and QoL in knee osteoarthritis patients. Given the study's limitations, further large-scale, multicenter RCTs are needed to confirm the rehabilitation effects and potential influencing factors of high-intensity exercise. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/PROSPERO/.