Flexor tendon rupture following repeated corticosteroid injections for carpal tunnel syndrome: A case report

Introduction: Corticosteroid injection (CSI) for carpal tunnel syndrome is a common diagnostic and therapeutic procedure. Adverse effects of corticosteroid injections are infrequent, though rare cases of flexor tendon rupture have been documented.

Presentation of case: We present a case of a 67-year-old female with acute loss of left index finger flexion due to rupture of the left index flexor digitorum profundus (FDP) and the flexor digitorum superficialis (FDS) tendons and left long finger FDS tendon following numerous carpal tunnel corticosteroid injections. Intraoperatively, she was also found to have a complete rupture of the long finger FDS and partial rupture of the long finger FDP. Side-to-side tendon transfers were performed to restore the flexor tendon function.

Discussion: The overall incidence of serious adverse effects in patients receiving CSIs for carpal tunnel syndrome, including flexor tendon rupture, intraneural injection or gangrene, is extremely low. Only three cases of flexor tendon ruptures following CSI for carpal tunnel syndrome have been reported in the literature. Given our patient's multiple CSIs per year over the course of 6 years, she may have been at increased risk of spontaneous tendon rupture given extra-articular CSIs can result in tendon rupture as a rare, but serious complication.

Conclusion: This case demonstrates that flexor tendon ruptures are a possible, although rare, complication following steroid injections for carpal tunnel syndrome. Proper injection techniques should be used to minimize adverse effects.