Extensor-pollicis-longus or -brevis tendon rupture after corticosteroid injection

Corticosteroids have been used for treating various musculoskeletal problems for more than five decades. They remain the drug of choice in rheumatology, orthopedics, and other areas. Most local corticosteroid injections are safe; however, complications may occasionally arise. Tendon rupture is uncommon after a local corticosteroid injection. We present two cases and review possible rupture mechanisms. In case 1, the patient presented with a painful swelling on the dorsal side of her right first metacarpophalangeal joint. An orthopedic surgeon prescribed three local corticosteroid injections over 4 weeks, and the patient experienced a sudden loss of extension on the distal phalanx of her thumb 3 weeks after the last injection. Two days later, the proximal phalanx of the thumb lost its extension. Surgical exploration revealed that the extensor-pollicis-longus and extensor-pollicis-brevis tendons were completely severed. Both tendon ends had edematous necrosis with collagen degeneration. In case 2, the patient presented with ruptures of the extensor-pollicis-brevis tendon and the radial collateral ligament of her first metacarpal joint after receiving a local corticosteroid injection. In case 1, functional recovery was achieved by repairing the extensor-pollicis-brevis tendon and by transferring the extensor indicis proprius tendon to the extensor pollicis longus. In case 2, the patient was lost to follow-up and did not undergo surgery. Most physicians overlook local-corticosteroid-injection-induced tendon injuries. We hope that such patients will alert all physicians to the risk of tendon rupture associated with corticosteroid injections.