Treatment of partial flexor tendon lacerations: the effect of tenorrhaphy and early protected mobilization.

Controversy exists in the literature regarding the proper treatment of partial flexor tendon lacerations. In this study, a novel nonweightbearing canine model was developed in order to closely approximate human flexor tendon conditions. The relative effects of immobilization, early protected mobilization, tenorrhaphy, and no repair of flexor tendon healing were evaluated by paired comparisons of four experimental groups (24 animals). Parameters evaluated after a 35-day healing period included tendon excursion, breaking strength, energy absorption, and stiffness. The contralateral digit-matched profundus tendon served as a normal control. Eight additional animals were studied histologically and by scanning electron microscopy. Data analysis revealed statistically significant adverse effects on breaking strength, stiffness, and energy absorption when repaired by modified Kessler technique. Early motion improved excursion and stiffness significantly, and resulted in more nearly normal tendon morphology than immobilized tendons. Thus, we conclude that partial flexor tendon lacerations of 60% cross-sectional area are optimally treated without tenorrhaphy and with early mobilization.