Many elderly patients suffer significant pain and functional limitation because of osteoarthritis of the knee. Although physical therapy can relieve symptoms, it frequently requires sophisticated equipment or intensive professional supervision. Thomas and colleagues assessed the ability of a simple home-based exercise program to reduce pain and improve physical function in patients with knee osteoarthritis.

After surveying more than 9,000 patients from general practices in Nottingham, England, the authors recruited 786 patients with knee pain (mean age, approximately 62 years). Patients who reported pain on most days were assessed clinically for inclusion in the study. Exclusion criteria included previous total knee replacement surgery, leg amputation, use of a permanent cardiac pacemaker, lack of knee pain within the previous week, and inability to provide informed consent.

Patients were taught an exercise program to maintain and improve muscle strength around the knee, range of motion of the joint, and locomotor function. The program used graded elastic bands to increase the resistance against which the muscles worked, thereby making the program progressively more challenging. The study subjects were encouraged to exercise both legs for 20 to 30 minutes every day and to increase repetitions to a maximum of 20 per leg. During the first two months, researchers visited the home of each participant four times to provide training and monitor exercise technique. Follow-up visits occurred every six months. Patients completed diaries to record adherence to the exercise program.

The study subjects were randomly assigned to four groups: exercise therapy, monthly telephone contact, exercise therapy plus telephone contact, or no intervention. The telephone contacts were maintained monthly to monitor symptoms and provide advice on knee pain management.

The primary outcome was reported knee pain as determined by the Western Ontario and McMaster universities (WOMAC) osteoarthritis index, which assesses pain, stiffness, and physical function. Secondary outcomes included changes in stiffness, quadriceps strength, and psychologic score.

After two years, 600 (76.3 percent) patients had completed the study. Study participants in the pooled exercise groups showed significant improvements in stiffness and physical function compared with those in the nonexercise groups. Isometric muscle strength was higher in the exercise groups, but general physical function, anxiety, and depression were no different in the groups at 24 months. Telephone support was found to contribute little to the reduction of knee pain.

Of the patients allocated to the exercise groups, 48.1 percent completed the program. Adherence to the exercise program was related to outcome. The dose-response effect was 0.42 for high adherence, 0.34 for medium adherence, and 0.16 for low adherence.

The authors concluded that simple home-based exercise therapy produces small but significant reductions in knee pain (12 percent), even with only moderate adherence. They suggested that future work might be directed at identifying specific patients who are likely to benefit most from a half hour of daily knee exercises.