Differences in the Outcomes of Early Active Mobilization Following Flexor Tendon Repair Between Zone 1 and Distal Zone 2 Injuries

Abstract

Purpose

Complete release of the A4 pulley is recommended for flexor tendon repair to allow smooth tendon excursion, provided the proximal sheath is mostly intact. However, it is unclear whether the active range of motion of finger joints differs when the flexor digitorum profundus tendon is repaired at different levels with A4 pulley release. We evaluated differences in the outcomes of flexor tendon repair of zone 1 and zone 2A injuries using a six-strand suture (the Yoshizu #1 technique) and complete release of the A4 pulley, followed by an early active mobilization protocol.

Methods

This retrospective case series analyzed 27 fingers from 22 patients: 12 index, 5 middle, 4 ring, and 6 little fingers. There were 13 zone 1 injuries in 12 patients and 14 zone 2A injuries in 10 patients. All tendons were repaired using the same technique, followed by a controlled active mobilization regimen initiated within the first three postoperative weeks. The follow-up period averaged 7 months (range: 3–13 months).

Results

No tendon bowstringing was evident in any finger. Rupture of one flexor tendon repair occurred 8 weeks after primary surgery in one patient with a zone 1 injury. Excluding this case, no significant differences were observed in the active range of motion of the two finger joints between patients with zone 1 and 2A injuries. However, active motion of the distal interphalangeal joint of zone 1 was significantly reduced compared with that of zone 2A, given the increase in the total extension deficit.

Conclusions

In this series, although complete release of the A4 pulley and postoperative treatment were performed in the same way, zone 1 injuries demonstrated greater total extension deficits and failed to achieve distal interphalangeal joint motion outcomes comparable with those observed in zone 2A injuries.

Type of study/level of evidence

Therapeutic IV.