Efficacy and safety of resistance training for knee osteoarthritis and subsequent knee replacement: A systematic review and meta-analysis

BACKGROUND: Resistance training is recommended for knee osteoarthritis, although its effectiveness and safety across different clinical stages and optimal prescription parameters remain unclear. OBJECTIVE: To assess the effectiveness and safety of resistance training across all stages of knee osteoarthritis, explore potential moderators, and compare it with other exercises. METHODS: Medline, Web of Science, Scopus, and Cochrane were searched from inception to July 10, 2024. Randomised controlled trials evaluating resistance training in individuals with knee osteoarthritis were included. Random-effects meta-analyses were conducted, with sensitivity analyses. Primary outcomes addressed physical function (eg, mobility tests); secondary outcomes included knee-specific patient-reported outcomes (eg, WOMAC). Safety was analysed using risk differences. Certainty of evidence was assessed using GRADE. RESULTS: 120 trials (10 253 participants) were included: 88 on early knee osteoarthritis, 13 on preoperative phases, and 19 after knee replacement. For primary outcomes, resistance training improved mobility, walking capacity, and knee extension strength in early osteoarthritis ccompared with control (SMD 0.46-0.81; moderate-to-high GRADE), knee extension strength in the preoperative phase (SMD 0.47; high GRADE), and mobility after knee replacement (SMD 0.58; moderate GRADE). For secondary outcomes, resistance training improved pain, stiffness/symptoms, physical function, and quality of life in early osteoarthritis (SMD 0.43-0.63; moderate-to-high GRADE), showed no significant effects preoperatively, and reduced knee pain after knee replacement (SMD 0.40; high GRADE). Moreover, resistance training showed non-significant risk differences versus controls in early osteoarthritis and in pre- and post-surgical phases. CONCLUSIONS: Resistance training may provide clinically relevant benefits across the knee osteoarthritis continuum without increasing risk. Resistance training should be considered as a core component of rehabilitation and conservative management strategies across all stages of knee osteoarthritis. PROSPERO NUMBER: CRD42024513524.