[Occult scaphoid-lunate dissociation in distal radius fractures]

The aim of this study was to investigate the clinical consequences of scapholunate dissociation associated with fractures of the distal radius and the impact on wrist function. Fractures of the distal radius and scapholunate dissociation overlap in pathomechanics. The diagnosis however is frequently missed initially.

We reviewed 45 consecutive patients with closed distal radius fractures with a mean follow up of 48 months. Ten patients underwent surgery and 35 patients were treated by fracture reduction and cast immobilization during 4.5 (range 3 to 8) weeks. All patients were re-examined clinically and radiographs of both wrists were compared.

Four patients showed evidence of SLD in the scapholunate joint region based on specific criteria (scapholunate gaps > 2 mm on anterior-posterior radiograph and the scapholunate angle > 60 degrees on lateral radiograph). All patients with SLD showed a poor radioulnar deviation. Three patients reported mild to moderate pain.

The difficulties in management of SLD may be avoided by early detection and treatment. In all investigated patients the diagnosis was missed after the initial trauma. Untreated SLD can lead to carpal collapse and arthrosis of the wrist, and ultimately to scapholunate advanced collapse.