Osteoarthritis is a common problem in the United States. The major joints usually affected by osteoarthritis are the hips and knees. Exercise therapy is considered an important component of the therapeutic regimen. Multiple studies suggest that exercise can improve outcomes in osteoarthritis; however, there are no definitive studies. Van Baar and colleagues studied the effectiveness of an exercise program in the treatment of osteoarthritis of the knees and hips.

The outcome measures in the study were pain levels, self-reported disabilities, observed disabilities and the patient's global assessment of the effect of the exercise program. Patients included in the study had an established diagnosis of osteoarthritis of the knees, hips, or both, determined by clinical and radiographic criteria. The authors performed an analysis of multiple studies, including at least one group of patients receiving exercise therapy as an intervention. The treatment program was also randomized. Each study was assessed for validity based on published standards.

Six of the 11 trials met at least one half of the validity criteria. A small to moderate improvement was shown in osteoarthritis of the knee; less improvement was noted in patients with hip disease. Self-reported and observed disability improved with exercise. Patient's global assessment of the effect of exercise improved during the studies. There were no differences between any of the exercise programs used in the various studies.

The authors conclude that exercise therapy is effective in patients with osteoarthritis of the hips and knees. The best results occurred in patients with mild to moderate osteoarthritis who were recruited from community and outpatient settings.