Carpometacarpal dislocation. An easily missed diagnosis.

We have reviewed 21 cases of dorsal dislocation of carpometacarpal joints. In 15 of them the diagnosis was missed when they were first seen in an accident and emergency department. General swelling may obscure the characteristic clinical deformity and routine radiographs may not show the displacement clearly. It is recommended that a true lateral radiograph of the hand be requested when this injury is suspected.