Aetiology of Kienböck's disease based on a study of the condition among patients with cerebral palsy.

Examination of 110 patients with cerebral palsy revealed a diagnosis of Kienböck's disease in six wrists in five cases. All had cerebral palsy of the mixed type with athetosis and high muscle tone. It is considered that the increased prevalence of Kienböck's disease in these cases was attributable to repeated minor trauma to the lunate from childhood due to high muscle tone across the wrist joint, together with negative ulnar variance. The high prevalence of Kienböck's disease observed in patients with cerebral palsy strongly suggests that repeated minor trauma together with negative ulnar variance is also the cause of Kienböck's disease in normal individuals.