Small flake, big problem: an unreported cause of extensor pollicis longus tendon rupture.

Fracture of the base of the third metacarpal with associated avulsion of the extensor carpi radialis brevis tendon is a rare injury. We report such a fracture and the unusual resulting complication of division of the extensor pollicis longus tendon by the avulsed bony fragment. Careful monitoring using lateral radiographs is needed to make the diagnosis and displacement of the avulsed fragment warrants open reduction and internal fixation.