Genu recurvatum loosely translates as backward-bending knee. It is also known as congenital dislocation of the knee (CDK) or congenital dislocation of the patella (CDP), and sometimes as congenital hyperextension. CDK is a rare condition with an incidence rate of approximately 1 per 100,000 live births. It is characterized by congenital hyperextension of the knee and marked limitation of flexion. Patients with this condition present with a patella that is dislocated laterally, permanently, and irreducibly. However, there is some disagreement with this description. Some suggest obligatory patella dislocation is a separate condition where the dislocation is hypoplastic to start and becomes fixed into the lateral position as the child grows. Some physicians believe this condition should be renamed developmental dysplasia and dislocation disorder (DDDP) to more accurately reflect it as a wide-spectrum disorder.