To evaluate physical therapy interventions for adults with knee osteoarthritis (OA), investigators from the University of Minnesota School of Public Health, University of Minnesota Medical School, and Minnesota Evidence-based Practice Center searched MEDLINE, the Cochrane Library, the Physiotherapy Evidence Database, Scirus, Allied and Complementary Medicine, and the Health and Psychosocial Instruments bibliography database from 1970 to February 2012. A total of 193 randomized, controlled trials (RCTs) published in English were included in the review. Means of outcomes, physical therapy interventions, and risk of bias were extracted to pool standardized mean differences. Disagreements between reviewers abstracting and checking data were resolved through discussion. Meta-analyses of 84 RCTs provided evidence for 13 physical therapy interventions on pain (58 RCTs), physical function (36 RCTs), and disability (29 RCTs). Meta-analyses provided low-strength evidence that aerobic (11 RCTs) and aquatic (3 RCTs) exercise improved disability and that aerobic exercise (19 RCTs), strengthening exercise (17 RCTs), and ultrasonography (6 RCTs) reduced pain and improved function.
Several individual RCTs demonstrated clinically important improvements in pain and disability with aerobic exercise. Other physical therapy interventions demonstrated no sustained benefit. Individual RCTs showed similar benefits with aerobic, aquatic, and strengthening exercise. Adverse events were uncommon and did not deter participants from continuing treatment.