Flexor digitorum profundus tendon injuries with or without flexor digitorum superficialis tendon repair: a randomized controlled trail

Flexor Zone 2, also called ‘the critical zone’ or ‘no man’s land’, presents challenges due to injuries that can result in damage to both the flexor digitorum profundus (FDP) and the flexor digitorum superficialis (FDS) tendons. The complexity of repairing tendons in this zone, along with the potential development of adhesions, can result in significantly impaired hand function. We aimed to evaluate the results, outcome, and necessity of repairing only the FDP tendon, versus repairing both the FDP and the FDS tendons, in a Zone 2 injury.

Ninety patients with acute flexor zone two injuries, who were being treated at the Plastic and Reconstructive Surgery Department at Cairo University, were included in the study. Patients were divided into three groups; Group (A) underwent isolated repair of the FDP tendon, Group (B) who underwent repair of the FDP tendon with a single slip of the FDS, and Group (C) who underwent repair of the FDP tendon with the two slips of the FDS tendon. Patients were randomly chosen by cyclic sequential allocation.

There was no significant difference between groups regarding TAM, TPM, Tang grading system or ASSH TAF Score system (p = 0.728, 0.654, 0.225 and 0.872 respectively). Moreover, DASH Score and DASH Score work related did not show significant difference between groups (p = 0.731 and 0.413, respectively).

The findings imply that the repair of the FDS is not mandatory in Zone 2 injuries. The decision to repair the FDS tendon during surgery depends on the smoothness of the tendon gliding and is made intraoperatively. 

Level of Evidence: Level III, therapeutic study.