Concomitant scapholunate dissociation and Kienböck's disease.

Six men had concurrent scapholunate dissociation and Kienböck's disease, a finding suggestive of a common cause. Five patients attributed the onset of wrist pain to a single traumatic event. Three had x-ray evidence of scapholunate dissociation before the onset of lunate osteonecrosis. Biomechanical factors that may be of significance are ulnar minus variance, lesser compliance of the triangular fibrocartilage, ulnar translation of the carpus at impact with shear fracture through the lunate, and disruption of the scapholunate interosseous membrane occurring under similar stress. Lunate osteonecrosis may depend on a susceptible vascular pattern or intraosseous injury or both. The development of lunatomalacia complicates an already unstable wrist. Treatment options vary according to the clinical stages of each condition, although contrasting treatments have not established optimal care.