A Case of Trigger Finger Following Longitudinal Tear of Flexor Digitorum Superficialis after Repeated Closed Injury

Choi, Hwan Jun; Choi, Eui Chul; Kim, Yong Bae

Abstract

PURPOSE
Many causes for triggering or locking of the fingers have been discussed in other literatures. The most common one is known stenosing tenosynovitis, which causes, a mismatch between the volume of the flexor tendon sheath and its contents. However, repeated trauma to the hand is uncommon cause of trigger finger. Therefore, we present a case of a rare condition of stenosing tenosynovitis which developed from a repeated relatively weak superficial flexor tendon injury.
METHODS
The patient was a 62-year-old woman who showed a painless, fixed and round mass on her right hand with no particular cause. Active and passive range of motion of the metacarpophalangeal joint of long finger was limited in flexion and extension. Ultrasonographic finding showed injured flexor digitorum superficialis tendon had fibrillar architecture with swelling between hyperechoic synovial membrane and hypoechoic surrounding area. Surgical exploration revealed that a bunched portion of the flexor digitorum superficialis and A1 pulley cause triggering during operation after adhesiolysis of scar tissue.
RESULTS
After releasing the A1 pulley, the range of motion of the metacarpophalangeal joint of long finger showed no limitation and histological examination of the subcutaneous tissue revealed fibrous fatty degeneration. In this case, releasing the A1 pulley with adhesiolysis of the subcutaneous scar tissue was successful and we obtained good functional outcome.
CONCLUSION
We examined a patient in whom a repetitive impact forces to the palm caused longitudinal tear of the flexor tendon, leading to trigger finger. We experienced a rare case of stenosing tenosynovitis and trigger finger caused after close injury to flexor digitorum superficialis and its degenerative changes that caused mass like effect. To the best of authors' knowledge, our case of close injury to the flexor digitorum superficialis and unique morphologic change before rupture of tendon is rarely to be reported.