The effect of division of the transverse carpal ligament on flexor tendon excursion.

The effect of the transverse carpal ligament (TCL) as a pulley was evaluated by measuring flexor tendon excursion after ligament division and by changing wrist position through a range of flexion and extension. Eight fresh cadaver upper extremities were mounted in a device and tendon excursions from full extension to fingertip-palm contact were measured for each flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) tendon. Measurements were performed with the wrist at 30 degrees extension, neutral, 30 degrees flexion, and 60 degrees flexion. The TCL was then sectioned, the skin was sutured, and the measurements were repeated. Two forms of carpal ligament repair were then done--transposition flap and aponeurotic repairs--and measurements were again repeated. With increasing wrist flexion, greater excursion differences were noted. Analysis of variance revealed that for both FDS and FDP, a significant difference in excursion occurred at 60 degrees wrist flexion and 30 degrees wrist extension with no ligament reconstruction or aponeurotic repair, compared to values prior to carpal tunnel release (p < .05) and to transposition ligament repair (p < .05).