The stiffness of the ankle joint after the ankle fracture is caused by the lack of normal movement or activity after the ankle fracture, which is related to the treatment method taken, such as conservative treatment, it may take 4-6 weeks to cast, and the activity is not allowed within these 4-6 weeks, once the activity leads to misalignment, it will affect the whole ankle joint, and the joint stiffness will definitely exist after the cast is fixed. The joint stiffness is inevitable after the cast. After the stiffness of the joint, proper functional exercises are required, as well as passive functional exercises and active functional exercises, but weight bearing is not allowed during this period. In addition, if the stiffness is postoperative, it may be due to the lack of early activity after surgery. The main purpose of the surgery is to prevent the function of the joint from being affected in the future by early movement, and proper exercise may improve the stiffness of the joint.