[Congenital dislocation of the knee in children--unusual condition of unknown etiology].

Congenital dislocation of the knee is a rare condition. It results in an inability to flex the knee. The condition is normally diagnosed clinically during the neonatal period and is verified by X-ray and/or ultrasound. Treatment is preferably non-operative with gradually increased passive flexion of the knee. In certain cases surgery may be justified. In a majority of cases, the children achieve acceptable knee-function after treatment. In the region of Sundsvall-Härnösand in Sweden, during the past seven years five children with congenital dislocation of the knee were born, which is a considerable accumulation of cases. This article describes these five children, their condition, possible etiology and strategies of treatment.