Relationship between severity of gonarthrosis and cardiovascular fitness.

Cardiovascular fitness was assessed in 3 groups of patients having varying severity of gonarthrosis. Group I consisted of 16 patients with severe knee symptoms scheduled for total knee arthroplasty. Group II included 17 patients with medically treated osteoarthrosis who were not considered surgical candidates because knee symptoms were not severe. Group III consisted of 14 healthy control patients with no lower extremity arthritis. All patients were evaluated with Hospital for Special Surgery knee scores, Arthritis Impact Measurement Scale questionnaires, and a cardiopulmonary exercise test using semi-upright bicycle ergometry. All patients achieved anaerobic threshold during exercise. Mean (+/- standard deviation) maximum oxygen consumption (VO2) at peak exercise was 13.9 +/- 3.3 for Group I, 16.2 +/- 4.1 for Group II, and 21.5 +/- 3.9 for Group III. Mean (+/- standard deviation) Hospital for Special Surgery score was 55 +/- 7 for Group I, 70 +/- 14 for Group II, and 100 +/- 1 for Group III. Lower Hospital for Special Surgery score was associated with lower VO2 at peak exercise, suggesting that inactivity secondary to more severe arthritic symptoms can result in cardiovascular deconditioning. The association between severity of gonarthrosis and cardiovascular deconditioning supports the concept that a regular exercise program should be recommended for patients with arthritis. Also, for patients who are surgical candidates, the practice of delaying total knee arthroplasty may be associated with worsening cardiovascular fitness, particularly when physical activity becomes more limited. The expected longevity of implant function as well as the effect of continued arthritic symptoms on cardiovascular fitness should be considered when determining the optimal time for a patient to undergo total knee arthroplasty.