Aerobic Exercise Intervention for Knee Osteoarthritis

Principal Investigator: Kenton R. Kaufman, Ph.D.
Project Coordinator: Kathie Bernhardt — bernhardt.kathie@mayo.edu

Figure 1: Subject descending stairs.

Arthritis is one of the most common causes of functional limitation and dependency in the United States. Individuals with osteoarthritis (OA) restrict joint motion and limit activity in order to decrease their symptoms. Conservative medical treatment of OA has been directed at improving functional status through reducing joint pain and inflammation and maintaining or restoring joint function. Exercise as an adjunct therapy in the clinical management of patients with OA of the knee, however, is not uniformly accepted.

This is a 4-year project to study the effect of exercise on 306 patients with knee OA in a prospective, randomized, controlled trial. The objectives are to quantitatively determine the effects of aerobic exercise on patients with knee OA, compared to a control group. The hypotheses for this study are: 1) clinical outcome measures will be better in patients enrolled in exercise programs than in control patients, 2) quantitative measures of lower extremity function will not decline over time with an effective aerobic exercise program, and 3) an effective exercise program for adults with degenerative joint disease is dependent on knee compartment involvement, OA stage, body mass index (BMI), and type of exercise prescribed.

measurements (x-rays, magnetic resonance imaging (MRI), computerized gait analysis, proprioception and strength) are obtained upon enrollment. Kinematic and kinetic data are collected in a motion analysis laboratory as subjects walk both over a level surface and ascending/descending a flight of 7 steps (Fig. 25). Knee joint space is measured from x-rays and cartilage thickness is measured from the MRI. In addition, subjects complete a general health status questionnaire (SF-36), disease site specific questionnaire (KOOS), visual-analog scale (VAS) rating of their pain, and an activity index (PASE) to assess current activity level. Subjects with verified knee OA are randomized into a control group or one of two exercise groups (treadmill walking or stationary cycling). The subjects in the exercise group are required to exercise three times a week for one year.

To date we have enrolled two hundred forty-eight of the three hundred six subjects. Recruitment is ongoing and we expect to enroll the remainder of the subjects within the next year.