Surgical management of the tendon sheath at different repair stages. Biomechanical and morphological evaluations of direct sheath closure, partial sheath excision, and interposing sheath grafting.

The effects of direct sheath closure, partial sheath excision, and interposing sheath grafting at different repair stages were evaluated in the chicken model. Primary repair was done after sheath incision and tendon transection, and delayed primary repair was done 4 days after sheath and tendon injuries. The sheath grafting was accomplished by interposing a patch of sheath between the longitudinal incision of the plantar sheath. Six weeks later, biomechanical tests for measuring gliding excursions of the repaired tendons, morphological examinations of the extent of adhesions, and histological observations of the closed sheath or the grafted sheath were carried out. At the primary repair stage, the sheath interposing graft achieved more significant gliding excursion than the groups of direct sheath closure (P less than 0.01) and partial sheath excision (P less than 0.001), and no difference was found between the latter two groups (P greater than 0.05). At the delayed primary repair stage, the sheath interposing graft group was better than the partial excision graft group (P less than 0.05), and the partial excision group was better than the direct closure group (P less than 0.001). The sheath graft and sheath closure at the primary repair stage prevented adhesion formation, but the directly closed sheath did not keep intact after the delayed primary repair and extensive adhesion occurred. In this paper, the importance of volume of the repaired sheath tunnel and possible reasons for results of the delayed primary sheath closure were discussed and the management of flexor tendon sheath for different injuries at different repair stages was suggested.