Early active mobilization after primary repair of the flexor pollicis longus tendon

Background: There have been few studies regarding primary flexor tendon repair of the thumb following early active mobilization, whereas there have been multiple such studies of the finger. This study examined the outcomes of patients who underwent early active mobilization after primary repair of the flexor pollicis longus tendon.

Methods: This study was a retrospective case series. Between 1993 and 2019, 17 thumbs of 17 consecutive patients with complete flexor pollicis longus tendon lacerations were treated using the Yoshizu #1 technique, followed by early active mobilization. The mean time between injury and primary flexor tendon repair was 2 days. Two thumbs had zone T1 injuries and 15 had zone T2 injuries. Mobilization of the thumb began on the first postoperative day with a combination of active extension and passive and active flexion. The mean follow-up period was 8 months. The percentage of total active motion of the thumb was regarded as the sum of the active motion of the two joints, divided by 140°. Functional outcomes were graded in accordance with the Strickland criteria.

Results: Three repair ruptures occurred in thumbs treated by inexperienced surgeons. Excluding tendon ruptures, the mean percentage of total active motion of the thumb was 83%. The mean active flexion of the interphalangeal and metacarpophalangeal joints was 62° and 64°. The mean extension deficit was 8.8° at the interphalangeal joint and 7.5° at the metacarpophalangeal joint. According to Strickland's criteria, repairs to eight thumbs were ranked excellent, three were good, one was fair, and five were poor.

Conclusions: Our results are not inferior to the findings of previous reports regarding early postoperative mobilization after primary flexor pollicis longus tendon repair, in terms of the acquisition of active thumb motion. Poor outcomes result from repair rupture and increased extension deficits of the interphalangeal and metacarpophalangeal joints.