This report aimed to present a case of wrist-tendon rupture and to discuss a rare complication after corticosteroid injection. A 67-year-old woman had difficulty extending her left-thumb interphalangeal joint several weeks after a palpation-guided local corticosteroid injection.
Passive motions remained intact without sensory abnormalities. Ultrasound examination showed hyperechoic tissues at the site of the extensor pollicis longus (EPL) tendon at the wrist level and an atrophic EPL muscle stump at the forearm level.
Dynamic imaging demonstrated no motion in the EPL muscle during passive thumb flexion/extension. The diagnosis of complete EPL rupture, possibly due to inadvertent intratendinous corticosteroid injection, was therefore confirmed.