Zone 2 Flexor Tendon Repair Location and Risk of Catching on the A2 Pulley

Is releasing pulleys during flexor tendon repair "part and parcel"? Narrative review of the current evidence

BACKGROUND

The complex hand flexors pulleys system is essential in achieving efficient flexor tendons' function. Previous cadaveric studies demonstrated that A2 and A4 are the crucial pulleys in maintaining normal digits biomechanics. Realistically, the preservation of A2 and A4 pulleys during repairing flexor tendon laceration in zones one and two can be extremely challenging. We review the current published evidence in this article to answer the question of whether releasing the pulleys cause bowstringing or affects clinical outcomes.

METHODS

Literature search of the available databases.

RESULTS

There was no published comparative evidence. Retrospective case series have reported that no clinical bowstringing was noted after releasing flexor pulleys during flexor tendon repairs. Outcomes have been reported according to Tang and or Strickland criteria to assess range of motion (ROM). No functional hand scores or patients' satisfactions scores have been reported.

CONCLUSION

Releasing flexor pulleys during tendon repair to allow access or prevent impingement of the repaired tendon does not seem to cause bowstringing or affect outcome based on the limited available evidence. Future research is needed.

LEVEL OF EVIDENCE

Level 4.

Widening of Pulley by Interdigitating Cuts

While biomechanically important, pulleys present multiple challenges to a zone 2 flexor tendon repair and rehabilitation. Retrieval of tendon through an intact pulley is cumbersome. Following repair, venting is often needed to accommodate the bulk at repair site. On occasion, step lengthening, or even complete division of pulley and reconstruction with tendon graft are necessary. Finally, accessing the tendon under the pulley during tenolysis is difficult. The primary issue in all such cases is the lack of space under the pulley. We describe a technique of expanding the pulley by interdigitating cuts. This technique greatly increases the diameter of the pulley which could be demonstrated in cadaver model and noted in clinical setting. This technique is easy to perform and maintains the integrity of the pulley without complete division. It would allow easy tendon retrieval, provide space for the repair and gliding, and improve exposure during tenolysis.