Gliding resistance of extrasynovial and intrasynovial tendons through the A2 pulley

The gliding ability of the flexor digitorum profundus tendon and of the palmaris longus tendon through the A2 pulley was compared, in terms of gliding resistance, with use of a system that we developed. Fourteen digits and the ipsilateral palmaris longus tendons from fourteen cadavera were used. The average gliding resistance at the interface between the palmaris longus tendon and the A2 pulley was found to be greater than that between the flexor digitorum profundus tendon and the A2 pulley under similar loading conditions. We concluded that the gliding ability of the palmaris longus tendon was inferior to that of the flexor digitorum profundus tendon in vitro. CLINICAL RELEVANCE: The findings of the present study are consistent with those of in vivo experiments in which extrasynovial tendon grafts have been associated with substantial formation of adhesions. The adhesions may be explained by the poor gliding ability of the palmaris longus tendon. The palmaris longus tendon may have limitations, because of gliding resistance, when it is used as a graft to reconstruct flexor tendons in the digits.