Work of flexion related to different suture materials after flexor digitorum profundus and flexor digitorum superficialis tendon repair in zone II: a biomechanical study.

PURPOSE: Repair of both flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) tendons is commonly performed in zone II flexor tendon injuries; however, the bulk of the repair may impair tendon gliding. We evaluated whether repairing 1 slip of FDS tendon and resecting the other would significantly decrease work of flexion and whether suture material affected this interaction in an in vitro study.

METHODS: The index, middle, and ring fingers from 10 fresh-frozen human cadaveric hands were disarticulated and their tendon sheaths opened. Baseline work of flexion was tested. Lacerations were made in zone II, and then the FDP tendon was repaired with 3 different suture materials: FiberWire, Ticron, and prolene. Work of flexion was again measured and the percentage increase calculated. Further iterations were performed with both slips of FDS tendon repaired and with one slip of FDS tendon repaired and the other resected.

RESULTS: There was no significant difference in the work of flexion after repairs done with FiberWire, Ticron, or Prolene. Work of flexion after repair of both FDP and FDS tendons increased 51% compared with an increase of 21% after FDP-only repair and an increase of 9% after repair of one and resection of the other slip of FDS. Repair of both FDP and FDS tendons significantly increased work of flexion.

CONCLUSIONS: Resection of 1 slip of FDS tendon significantly reduces work of flexion in zone II flexor tendon repair. Suture material had no effect on this interaction.