BIOMECHANICAL CHANGES AFTER CARNAL TUNNEL RELEASE - A CADAVERIC MODELFOR COMPARING OPEN, ENDOSCOPIC, AND STEP-CUT LENGTHENING TECHNIQUES

We used a previously described cadaveric model for evaluating changes in flexor tendon biomechanics after open carpal tunnel release to eval uate endoscopic and step-cut lengthening techniques. A 26% and 18% inc rease in tendon excursion consumed by wrist motion was demonstrated fo r flexor digitorum profundus and flexor digitorum superficialis tendon s respectively after open transection of the transverse carpal ligamen t. A 21% and 15% increase in tendon excursion was demonstrated after e ndoscopic carpal tunnel release and a 21% and 16% increase after step- cut lengthening of the transverse carpal ligament. Increased excursion was noted after 20-30 degrees of wrist flexion as tendon bowstringing occurred. Although division of the transverse carpal ligament by all methods resulted in a significant increase in tendon excursion, the di fferences between methods of carpal tunnel release were not significan t. This cadaveric study evaluates one potential cause for weakness aft er carpal tunnel release, palmar displacement of the flexor tendons, w hich results in increased flexor tendon excursion consumed by wrist mo tion.