Shoulder rotational strength, movement, pain and joint tenderness as indicators of upper-extremity activity limitation in moderate rheumatoid arthritis

In this study 32 women were investigated in order to elucidate how shoulder rotational muscular strength and upper-extremity impairments are associated with activity limitation in moderate rheumatoid arthritis. A regression analysis was carried out to determine whether these variables could indicate the outcomes of a shoulder-arm disability questionnaire (SDQ) comprising three parts, plus parts of the Health Assessment Questionnaire, the Functional Status Questionnaire and the Sickness Impact Profile. Shoulder-arm and wrist movements were moderate-to-good (r = 0.53, p < 0.01 and r = 0.58, p < 0.01, respectively) in relation to isometric internal rotational strength. The relationship between isokinetic concentric and eccentric internal rotational strength was moderate-to-good (r = 0.59, p < 0.01). Isokinetic eccentric internal rotation strength, shoulder-arm movement, joint tenderness and pain variables together indicated 25-61% (adjusted R-2) Of the variation in SDQ, Eccentric strength had the highest adjusted R-2 (41%) in relation to SDQ 1, covering mainly personal hygiene. Shoulder rotational strength did not indicate the more general instruments, Thus, hand and elbow impairments also are probably important in explaining activity limitations.