Exercise Good for Early Knee Osteoarthritis

Oct. 28, 2005 -- A new study may help dispel the notion that exercise might do more harm than good for people with early symptoms of osteoarthritis of the knee.

Rather than put additional "wear and tear" on damaged knee joint cartilage, Swedish researchers found that moderate exercise actually strengthened joint cartilage as well as reduced pain in people at high risk for developing osteoarthritis.

Osteoarthritis is the leading cause of disability among adults. The condition causes joint pain, swelling, and eventually loss of function in the affected joint. It commonly affects the knees and hips, but other joints can also be affected.

Osteoarthritis and Exercise

Studies have shown moderate exercise can reduce pain and slow the progression of osteoarthritis of the knee and hip. But more than 60% of American adults fail to meet the minimum recommendations for physical activity.

Osteoarthritis is caused, in part, by the gradual wear and tear on the joints, which has prompted the belief that exercise may aggravate cartilage loss.

Researchers say that until recently, it was impossible to disprove that notion because standard X- rays could only show severe cartilage damage after it occurred.

But advances in magnetic resonance imaging (MRI) now allow researchers to detect changes in cartilage earlier in the course of osteoarthritis.

Exercise May Prevent Osteoarthritis of the Knee

In the study, published in Arthritis & Rheumatism, researchers used MRI technology to examine the impact of moderate exercise on the knee cartilage of 30 men and women who had undergone the same kind of knee surgery three to five years earlier, which would place them at high risk for developing osteoarthritis of the knee.

Half of the group was enrolled in a supervised exercise program combining aerobic and weight-bearing exercise for a one-hour program three times a week and the other half acted as controls.

After four months, MRI scans were used to evaluate knee cartilage, and the participants answered questions about their knee pain and stiffness.

The results showed that many of those in the moderate exercise group reported gains in physical activity and joint function, which were confirmed by tests of aerobic performance and stamina. In addition, the scans showed that the exercise group experienced improvement in a key strength component of cartilage.

"This study shows compositional changes in adult joint cartilage as a result of increased exercise, which confirms the observations made in prior animal studies but has not been previously shown in humans," says researcher Leif Dahlberg, in a news release.

The changes suggest that human cartilage responds to exercise in a way that is similar to muscle and bone and may have important implications for preventing osteoarthritis of the knee in those at risk.

But the size of the study was small and additional studies will be needed to confirm these findings.