Limitation of flexion and extension after comminuted fracture of the humeral ankle is caused by stiffness of joints and muscles, which can be relieved by local massage or with rehab exercises. 1. Massage: Since the comminuted fracture needs to be fixed externally for about three months after the operation, it will cause muscle stiffness and joint movement limitation in the case of long-term non-exercise and occurrence. After judging that the fracture is basically healed and the bones are stabilized, external massage can be carried out appropriately to effectively relax the muscles and joints through repeated massage, which can help to restore muscle strength and joint movement. 2. Rehabilitation exercises: For severe limitation of movement or joint stiffness, rehabilitation exercises can be considered under the guidance of a doctor. Stretching, bending and rotating the joints and muscles according to the specific area of restriction can help relieve muscle stiffness. When joint and muscle limitations occur after fracture healing, it is recommended to gradually increase activity levels to regain mobility. However, recovery exercises should be performed under professional supervision.