Osteoarthritis (OA) is the leading cause of disability among adults. As the population ages, increased intervention efforts are vital to controlling the individual and public health toll of this chronic, crippling joint disease.
Along with early diagnosis, moderate exercise is one of the most effective ways to reduce pain and improve function in patients with OA of the knee and hip.
Radiographs, the standard measure of OA's progression, made it impossible to assess cartilage before severe cartilage damage had occurred. However, advances in magnetic resonance imaging (MRI) now make it possible to study cartilage changes earlier in the course of OA.
Recently, researchers writing in the November 2005 issue of Arthritis & Rheumatism, describe the use of a novel MRI technique to determine the impact of moderate exercise on the knee cartilage of subjects at high risk for developing OA. The main aim of the study was to evaluate the effects of moderate exercise on glycosaminoglycan content in knee cartilage in subjects at high risk of knee osteoarthritis.
The authors recruited middle-aged men and women (29 men and 16 women), between the ages of 35 and 50, with a history of surgery for a degenerative meniscus tear within the past 3 to 5 years. Subjects were randomly assigned to either an exercise group or a control group. The exercise group was enrolled in a supervised program of aerobic and weight-bearing moves, for 1 hour, 3 times weekly for 4 months. At the study's onset and follow-up, subjects from both groups underwent MRI scans to evaluate knee cartilage. The technique used focused specifically on the cartilage's glycosaminoglycan content, a key component of cartilage strength and elasticity. Subjects also answered a series of questions about their knee pain and stiffness, as well as their general activity level. Of the original 45 subjects, 30--16 in the exercise group and 14 in the control group--completed the trial and all post-trial assessments.
In the exercise group, many subjects reported gains in physical activity and functional performance tests compared with subjects in the control group. Improvements in tests of aerobic capacity and stamina affirmed the self-reported changes. Also, MRI measures of the glycosaminoglycan content showed a strong correlation with the increased physical training of the subjects who had regularly participated in moderate, supervised exercise.
This in vivo cartilage monitoring study in patients at risk of knee OA who begin exercising indicates that adult human articular cartilage has a potential to adapt to loading change.
Moderate exercise may thus be a good treatment not only to improve joint symptoms and function, but also to improve the knee cartilage glycosaminoglycan content in patients at high risk of developing OA.