Ankle injuries without fractures do not necessarily require cast immobilization, depending on the injury. The most common type of ankle injury is sprain, when it is easy to cause the local ligament tissues become loose, the joint capsule and articular cartilage damage, destabilizing the ankle joint, and repairing these damages requires a specific time and environment. If the ankle joint becomes unstable, it is easy to cause secondary injuries when walking or playing sports. A cast can fix the ankle joint in a functional position, so that the injured part can have sufficient rest, provide a stable environment for the ligament tissue to recover, so as to avoid re-injury during activities, and also help to reduce the swelling and relieve pain. If you don’t put on the plaster or remove it by yourself after putting on the plaster, repeated activities will affect the repair of the ankle ligaments and so on, and chronic pain, habitual sprains and other sequelae may occur in the future. Other more minor ankle injuries that have not damaged the stability of the ankle joint and have not injured the ligaments and other soft tissues can be immobilized without a cast. When the ankle injury has no fracture, let the professional doctor to identify and confirm, if necessary, fixed cast.