Level 1: Likely reliable evidence
Therapeutic exercise of the knee (strength training in particular) reduces pain and improves physical function in patients with knee osteoarthritis, based on two systematic reviews. A Cochrane review of 32 randomized trials compared land-based therapeutic exercise vs. nonexercise (Cochrane Database Syst Rev. 2008[4]:CD004376). Exercise reduced knee pain in a meta-analysis with 3,616 patients and improved self-reported physical function in a meta-analysis with 3,719 patients. In another systematic review, 18 randomized trials evaluated resistance training interventions in 2,832 adults with primary knee osteoarthritis (Arthritis Rheum. 2008;59:1488-1494). Four of five high-quality trials reported statistically significant improvements in pain and function.