Biomechanics and Motion Analysis

Aerobic Exercise Intervention for Knee Osteoarthritis

Principal Investigator: Kenton R. Kaufman, Ph.D.
Project Coordinator: Christine Hughes — hughes.christine@mayo.edu

Figure 30: Subject descending instrumented 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.

A complete orthopedic examination and objective biomechanical measurements (x-rays, magnetic resonance imaging (MRI), computerized gait analysis, proprioception and strength) will be obtained upon enrollment. Kinematic and kinetic data will be collected in a motion analysis laboratory as subjects walk both over a level surface and ascending/descending a flight of 7 steps (Figure 30). Knee joint space will be measured from x-rays and cartilage thickness will be measured from the MRI. In addition, subjects will 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 will be randomized into either a control group or one of two exercise groups (treadmill walking or stationary cycling). The subjects in the exercise group will be required to exercise three times a week for one year.

To date we have seen sixty subjects for their initial visit. All of the subjects have been randomized with one third of the subjects in the control group and the remaining two thirds exercising. Recruitment is ongoing and we expect to see the remainder of the subjects within the next year.