There have been numerous reports on dislocation of the extensor tendons in the fingers. We describe an acquired dislocation of the extensor tendons of the thumb. We report a case with posttraumatic dislocation of extensor pollicis brevis (EPB) over the metacarpophalangeal (MCP) joint of the thumb. Ulnar dislocation of the EPB took place during a firm grip on a badminton racket and the patient could not extend the thumb from this position. After reconstruction of the extensor aponeurosis to centralize the EPB tendon the patient recovered normal function of thumb extensors.