Functional and biomechanical assessment of the normal and rheumatoid hand.

OBJECTIVE: To assess hand function in accordance with its accepted definition and to compare the results of three different assessment techniques.
DESIGN: A clinical-type assessment was used together with measurement of pinch grip and three-dimensional biomechanical trials.
BACKGROUND: Traditional clinical assessment may not relate to a patient's actual hand function. If hand function is defined as "the ability to use the hand in daily activities" then it is more appropriate to measure the forces available for performing everyday tasks using biomechanical tests.
METHODS: Eight female patients with rheumatoid arthritis and eight control subjects were recruited for the study. Volunteers underwent a clinical-type assessment using a six-task activity board. Lateral pinch grip of both hands was measured using a custom-built transducer. Biomechanical trials were conducted using a 6 degree-of-freedom transducer and 6-camera motion analysis.
RESULTS: Functional differences between the two subject groups were apparent using all three methods of assessment. Pinch strength correlated well with the biomechanical trial data but results from the clinical-type assessment provided only a weak correlation.
CONCLUSIONS: Clinical-type assessments do not give an accurate measure of hand function. Pinch strength measurements can provide a cost-effective alternative to full biomechanical analysis. RELEVANCE: Traditional functional assessment uses measurements of grip or pinch strength and range of motion together with a subjective assessment of activities of daily living. This study demonstrates that pinch strength measurements can provide an accurate measure of hand function. The results from activity-board trials do not reflect hand ability and are of limited use for hand evaluation.