A fracture is a break in the continuity and integrity of the bone caused by an external force. The healing process of a fracture consists of four periods, the hematoma mechanization period (hours after the fracture occurs), the scab formation period (days after the fracture occurs), the scab connection period (weeks after the fracture occurs), and the fracture contouring period. When the calf fracture is one month old, it is in the period of bone scab connection. During the process of bone scab formation and connection, the fracture end should be kept still and fixed, which is favorable for the recovery of fracture contouring and strength, and the cast can not be removed. Generally in 10~12 weeks after the fracture, the fracture end of the calf is completely connected, can bear certain stress, X-ray examination of the fracture healing well, under the guidance of the doctor to remove the cast.