Validity of pulp-to-palm distance as a measure of finger flexion

This study investigated the validity of pulp-to-palm distance measures as c linical indicators of finger flexion capacity. Pulp-to-palm distance and go niometry of the metacarpophalangeal, proximal interphalangeal and distal in terphalangeal joints were measured by a single tester in 50 patients with a bnormal digital flexion using a computerized hand assessment system. The co rrelation between pulp-to-palm distance measurements and total finger flexi on measures obtained by goniometry, was moderate (r = -0.46 and -0.51). Thi s indicates that the measures are not interchangeable. The relationship bet ween an upper extremity disability score (DASH) and restricted motion was s tronger for the goniometric measurements (r = 0.45, P < 0.01) than for the pulp-to-palm distance measurements (r < 0.30, P > 0.01). Both types of rang e of motion measurements were able to discriminate between minimal and subs tantial upper extremity disability. Further methodological evaluation is re quired to support the use of pulp-to-palm distance measures as an outcome i ndicator.