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°extension, neutral, 30°flexion, and 60°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°wrist flexion and 30°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).