Initially Unrecognised Lunate Dislocation As a Cause of Carpal Tunnel Syndrome

A patient was admitted reporting tingling pain and numbness in the right hand. Neurological examination--including nerve conduction studies--diagnosed carpal tunnel syndrome. Operative carpal tunnel release was performed without complications. Four months postoperatively the otherwise healthy patient presented again due to persistent complaints, although preoperative symptoms had improved. On this occasion, the patient reported loss of strength accompanied by rigidity in the wrist. Clinical examination showed some swelling adjacent to the operation wound. A postoperative ganglion cyst was suspected and a conservative treatment option--splinting the wrist--was chosen. Four weeks later the patient presented again with further swelling and increasing rigidity of the wrist. Surgical intervention was planned. Preoperative plain radiographs of the wrist revealed chronic palmar dislocation of the lunate to be the cause of the symptoms in our patient. Radiological signs of scapholunate advanced collapse arthritis (SLAC wrist) were also observed.