Isolated Dorsal Dislocation of the Lunate

Abstract

Lunate dislocations are well described in the volar direction as part of the perilunate dislocation, sometimes together with fractures of the other carpal bones or distal radius, as described by the anatomical studies of Mayfield [1]. It is a result of disruption of the complex inter-carpal and radiocarpal ligaments that hold the well conforming carpus in their normal position. Given the strength of these structures a significant trauma is required to cause them to fail.

However, we present a case of a patient who not only presented with relatively trivial trauma that resulted in a lunate dislocation, but it was also in the dorsal direction and not associated with any fracture or neurological compromise. In addition, she presented several days after her injury.

We treated her with closed manipulation and percutaneous K-wire fixation followed by a short period of immobilisation in a Plaster-of-Paris cast, with rapid return to full duties at work.

As many volar lunate dislocations may be missed at presentation, we suggest that in patients with relatively trivial trauma there should also be a suspicion of the lunate dislocating dorsally, which may be treated successfully without the aggressive open surgery usually required in volar perilunate dislocations.