Club foot is a congenital deformity involving one foot or both. The affected foot appears to have been rotated internally at the ankle. Without treatment, people with club feet often appear to walk on their ankles or on the sides of their feet. However, with treatment, the vast majority of patients recover completely during early childhood and are able to walk and participate in athletics just as well as patients born without CTEV. It is a relatively common birth defect, occurring in about one in every 1,000 live births. Approximately half of people with clubfoot have it affect both feet, which is called bilateral club foot. In most cases it is an isolated disorder of the limbs. It occurs in males twice as frequently as in females.