Hand grip function in patients with rheumatoid arthritis.

A new electronic dynanometer was developed and used to determine hand grip function in patients with rheumatoid arthritis. Triplicate pressure-time recordings of grip for each hand were used to calculate maximum grip strength, time required to reach 95% maximum grip strength (t95), total work and maximum power output. Measurements were done on 30 women aged 32 to 74 years (mean, 53 years) who had rheumatoid arthritis and 20 healthy women aged 37 to 69 years (mean, 50 years). The values obtained for patients and healthy women showed that the dominant hand was stronger than the nondominant hand in all women. However, all tests in patients with arthritis indicated decreased function and strength, the relative decrease being greater for nondominant hands compared with dominant hands. This new approach to measurement of hand grip function may provide better discrimination in the quantitative assessment of morning stiffness and response to changes in drug therapy. The time required to achieve 95% of maximum grip strength and maximum power outputs in particular appear to be more sensitive indicators of function than the standard maximum grip strength measurement.