The excursion of the tendon of flexor pollicis longus and its relation to dynamic splintage

In a cadaveric study the excursion of the flexor pollicis longus tendon has been measured over the proximal phalanx and metacarpal bones in relation to the angles of flexion of the interphalangeal (IP) and metacarpophalangeal (MP) joints. A small amount of tendon excursion is noted (1.3 mm for 10 degrees of IP joint flexion alone, 1.6 mm for 10 degrees of MP joint motion alone). It is emphasized that there is no tendon excursion over the proximal phalanx on MP joint motion. The significance of these measurements is considered in relation to current techniques of dynamic mobilization after tendon repair. Fixation of the MP joint and mobilization of the IP joint alone can achieve on an average a 70% increase in tendon excursion at the repair site over the proximal phalanx in comparison with dynamic splintage allowing free motion of both joints. The increase in excursion is greater in patients with more mobile MP joints.