Feasibility of Maximal Cardiopulmonary Exercise Testing in Patients With End-Stage Arthritis of the Hip and Knee Prior to Total Joint Arthroplasty

Abstract

Although no studies exist, to our knowledge, that examine the feasibility and safety of stress testing in a consecutive series of patients with severe arthritis, musculoskeletal conditions are often listed as relative contraindications to graded exercise testing. The current study was designed to examine the feasibility of maximal exercise testing in patients with end-stage arthritis prior to total joint arthroplasty. An observational and descriptive study in a consecutive series of patients with severe arthritis. This study was conducted in the outpatient clinics and cardiopulmonary exercise physiology laboratory of a rural teaching hospital. Sixty-one patients with severe osteoarthritis and rheumatoid arthritis were recruited from the orthopedic surgical service immediately before total joint arthroplasty of the hip, knee, or both. A reference group of 23 nonarthritic control patients were recruited from the general medical population of the same hospital and subjected to measures of arthritis severity. The severity of arthritis was graded by assessment of variables reflective of subjective symptoms, lifestyle impact, joint deformity, and radiographic abnormality. Arthritic subjects underwent a single graded, maximal, symptom-limited, cardiopulmonary exercise test using an electronically braked ergometer and a metabolic cart. Subjects were first asked to pedal with their legs; those apparently incapable performed the same task using their arms. Ninety-five percent of subjects who presented for an exercise test were capable of symptom-limited exercise. Of 29 patients evaluated before hip replacement, 66% completed leg tests, 31% completed arm tests, and 3% were incapable of symptom-limited exercise. Of 30 patients evaluated before knee replacement, 57% completed leg tests and 37% completed arm tests, while 7% were incapable of symptom-limited exercise. Two patients were evaluated before hip and knee surgery; one completed a leg study and one completed an arm study. Among the 37 subjects completing leg tests, a mean percentage of age-predicted maximum heart rate (APMHR) of 92 +/- 11% and a mean respiratory exchange ratio (RER) of 1.15 +/- 0.13 were noted. Among the 21 completing arm tests, a mean percentage of APMHR of 87 +/- 11% and a mean RER of 1.10 +/- 0.10 were observed. High rates of achievement of physiologic values indicative of maximal exercise (80% or more of APMHR and RER > or = 1.0) were noted in individuals in both exercise groups. Similar findings were noted regardless of the patient's subjective symptomatic limitation to exercise and the presence or absence of documented or suspected coronary heart disease. Most patients with severe arthritis are capable of maximal, symptom-limited exercise using ergometry methods. Ergometry stress testing may be a viable, low-cost alternative to dipyramidole-thallium testing or cardiac catheterization in some patients with arthritis warranting objective assessment of known or suspected cardiac disease.