Locking of the thumb in a patient with de Quervain's disease: a case report.

We report a patient with a locked left thumb in association with de Quervain's disease. While bathing her baby 1 month after giving birth a 32-year-old woman suddenly noticed that she could not radially abduct her left thumb. Magnetic resonance imaging showed thickening of the abductor pollicis longus tendon with a heterogeneous signal intensity on T2-weighted images. Bandage fixation for 4 weeks did not improve her thumb movement, and she was subsequently treated by surgery. Operative findings revealed inhibition of the tendon gliding proximally as a result of nodule formation in the abductor pollicis longus tendon distal to the first dorsal compartment. This condition, locking of the thumb, was improved by excising the extensor retinaculum of the first dorsal compartment and tenosynovium around the abductor pollicis longus and extensor pollicis brevis tendon. At the 1-year follow-up examination the patient had no limitations or pain during active radial abduction of the left thumb.