Review Question - QID 4542

In zone II flexor tendon injuries, repairing only one slip of FDS has been shown to improve gliding when compared to repair of both slips.

Zone II flexor tendon injuries have notoriously had poor outcomes secondary to high rates of adhesion formation at the pulleys. However, new advances in post-operative rehabilitation have significantly improved outcomes to the point where it is no longer considered "no man's land." Management of the FDS has been a source of controversy. In the past, the FDS was occasionally excised to theoretically make more room for the FDP. This has now been largely abandoned and the FDS is repaired whenever possible. Whether or not to repair both slips of FDS remains controversial, with in vitro data suggesting that gliding resistance is improved if only one slip is repaired.

Zhao et al. review the effect of partial vs. complete FDS excision following repair of FDP for zone II flexor tendon injuries. Preserving the whole FDS resulted in a significantly larger increase in gliding resistance after FDP repair than did full or partial FDS removal, which were not significantly different from each other.

Illustration A shows the zones of flexor tendon injury. Note that zone II injuries occur between the FDS insertion and the distal palmar crease. Illustration B shows the anatomy of the flexor tendons in detail. Video V shows a technique for repair of zone II injuries.

Incorrect Answers:
Answer 1: In zone II, the FDS and FDP are located within the same tendon sheath.
Answer 2: While the FDS was excised in the past, clinical outcomes have recently been shown to be improved with repair of either one or both slips.
Answer 4: Repairing FDS has been shown to increase digit strength.
Answer 5: Repair of FDP has been shown to improve long-term clinical outcomes.