Changes in digital flexor tendon mechanics after endoscopic and open carpal tunnel releases in cadaver wrists.

Digital flexor tendon excursion due to isolated wrist motion was measured in 5 cadaver wrists. Five sequential experimental conditions were tested: (1) intact wrists, (2) after single-incision endoscopic carpal tunnel release, (3) after addition of a distal endoscopic portal, (4) after conversion to an open palm incision, and (5) after suturing of the palm incision. Combined tendon excursion increased 27.8% after 1-incision and 29.7% after 2-incision endoscopic release; both increases were significant. A further increase in combined excursion to 43.4% over the value in intact wrists was measured after conversion to an open palm incision. Combined flexor tendon excursion after open release was significantly greater than excursion after either type of endoscopic release. Increases in excursion were also significant when flexor digitorum superficialis and flexor digitorum profundus tendons were considered separately. Excursion did not change significantly after skin suturing. These findings suggest that digital flexor tendon mechanics are closer to normal after endoscopic carpal tunnel release than after open release. It remains to be shown whether the difference is an advantage of endoscopic release over open release in the clinical setting. (J Hand Surg 2000; 25A:112-119.