Clubfoot (or talipes equinovarus) is a congenital malformation that causes the foot to turn inward and downward, affecting one or both feet. The exact causes are unknown, but genetic factors may be involved. Clubfoot results from abnormal development of the muscles, tendons, and bones of the fetus. Shortening of the tendons and ligaments inside the leg causes the foot to turn inward. A shortened Achilles tendon contributes to the stiffness of the foot. In about 50% of cases, clubfoot is bilateral.