To review the effectiveness of exercise therapy in patients with osteoarthritis (OA) of the hip or knee.
A computerized literature search of Medline, Embase, and Cinahl was carried out. Randomized clinical trials on exercise therapy for OA of the hip or knee were selected if treatment had been randomly allocated and if pain, self-reported disability, observed disability, or patient's global assessment of effect had been used as outcome measures. The validity of trials was systematically assessed by independent reviewers. Effect sizes and power estimates were calculated. A best evidence synthesis was conducted, weighting the studies with respect to their validity and power.
Six of the 11 assessed trials satisfied at least 50% of the validity criteria. Two trials had sufficient power to detect medium-sized effects. Effect sizes indicated small-to-moderate beneficial effects of exercise therapy on pain, small beneficial effects on both disability outcome measures, and moderate-to-great beneficial effects according to patient's global assessment of effect.
There is evidence of beneficial effects of exercise therapy in patients with OA of the hip or knee. However, the small number of good studies restricts drawing firm conclusions.