Flexor pollicis longus rupture in a trigger thumb after intrasheath triamcinolone injections: a case report with literature review.

We report an unusual case of a rupture of the flexor pollicis longus tendon after two intrasheath triamcinolone injections for left trigger thumb in a 56-year-old woman. Tendon grafting from proximal to the wrist to the fingertip was carried out using the palmaris longus tendon. The clinical result was evaluated as good according to Strickland's criteria. Recently, intrasheath triamcinolone injection has been thought of as a mainstay of the treatment for trigger digits. However, flexor tendon ruptures have been reported as a serious, rare complication following the injections suspected to be the result of intratendinous injection. To avoid this complication, it is considered important to perform correct injection into the tendon sheath. Moreover, it is recommended that the number of injections should be once or twice, that a dose of triamcinolone should be less than 10 mg, and that, for preventing the flexor tendon rupture, intervals between injections should be more than three months. Given the potential for tendon rupture, surgeons should certainly recognize and alert patients to the risk of tendon ruptures even after only a few steroid injections.