[Congenital dislocation of the knee (CDK)]

Congenital dislocation of the knee (CDK) is a rare deformity presenting itself either as an isolated idiopathic entity or in the context of syndromes like arthrogryposis, myelodysplasia or Larsen syndrome. Patients can be diagnosed clinically after childbirth based on hyperextension of the knee. Confirmation of the diagnosis is done by X-ray or sonography. Many theories concerning the pathogenesis have been proposed since CDK was described; according to recent literature fibrosis and contracture of the m. quadriceps is the most likely reason. Therapy should start as soon as possible after birth, conservatively using redressing casts or operatively in syndromal conditions aiming for reduction. The prognosis concerning re-dislocation is benign; a good outcome was shown for idiopathic CDK.