Knee braces have found their applications in a wide range of problems and illnesses. Functional knee braces are designed to replace damaged ligaments. For instance, a patient who has an ACL tear can be offered to wear a knee brace to allow certain activities to be performed without surgery. Prophylactic knee braces are used to prevent injury to the knee. Prophylactic knee braces are worn by sportspeople who engage in some high-risk sports to reduce their risk of a knee injury.