Chronic Lunate Dislocation: An Unusual Cause of Carpal Tunnel Syndrome—Avoiding Diagnostic Pitfalls and Synopsis of Management Options

ABSTRACT Carpal tunnel syndrome (CTS) represents the most common compressive neuropathy of the upper limb (1). There are a myriad of causes of CTS, of which carpal fractures and dislocations are known aetiologies. Volar lunate dislocations are the most common carpal dislocations described (1). Approximately 25% of perilunate dislocations are missed on initial presentation, resulting in delayed diagnosis and likely poorer outcomes (1-3). A case of chronic lunate dislocation presenting as CTS is presented here to highlight diagnostic pitfalls and management options.

Carpal Tunnel Syndrome and Rupture of Flexor Tendon Associated from Neglected Anterior Lunate Dislocation

Anterior dislocation of lunate is rare, it can result in median nerve compression and attritional rupture of flexor tendon when delay diagnosed. We report a patient with second finger flexor tendon rupture and carpal tunnel syndrome caused by neglected anterior lunate dislocation. Patient underwent operative treatment for that excised lunate, released carpal tunnel and reconstructed second flexor tendon using palmaris longus tendon. One year after surgery, fucntional and neurologic symptom were recovered. Also carpal alignment was maintained on plain radiographs, even after excision of the lunate.

Treatment of Anchor Suture with Kirschner Wires Fixation for Chronic Perilunate Dislocation

Chronic lunate dislocations are very rare injuries comprising of less than 10% of all wrist injuries. Volar lunate dislocations account for less than 3% of perilunate dislocations. We present a case of a missed volar lunate dislocation for 6months after initial injury. He fell down and had hyperextension injury during his sports activity. When the patient visit in our hospital, neurologic symptom was developed in distribution of median nerve. Tingling sensation and radiation symptom was found in affected hand. A plain radiograph revealed a volar lunate dislocation. Nerve conduction studies confirmed compression of the median nerve at the wrist, carpal tunnel level. Operation was performed with open reduction of lunate, fixation with K-wires and anchor suture. The outcome was excellent in relieving pain, function, range of motion, grip strength. There was improvement in Mayo wrist score and disabilities of the arm, shoulder and hand score. So we report a patient and a operation technique which can be considered in similar cases.

Lunate Dislocation (A Review of Six Cases) / 대한정형외과학회잡지

Six cases of lunate dislocation were treated in the departments of orthopaedic surgery, Hangang Sacred Heart Hospital and Kangnam Sacred Heart Hospital, Hallym College during the period from March 1, 1978 to August 31, 1982. The results were as follows; l. Among the total 6 cases, two cases had lunate dislocation only and the other four had associated injuries of the same wrist joints. 2. Marupulative reduction was successful in only one case. Five cases were treated by open reduction, and for four of them internal fixation was tried. 3. Postoperative roentgenograms showed acceptable reductions in all cases except one which redislocation occurred. This case showed lunate dorsiflexion instability and was treated with extensor carpi radialis longus tenodesis. 4. The cases with pure lunate dislocation yielded better functional recovery than those with associated carpal injuries.