The fracture healing process is generally divided into three periods, mainly including the hematoma mechanization period, the bone scab formation period and the bone scab remodeling period, the time required and the changes in the body are as follows: 1. Hematoma mechanization period: the hematoma mechanization period is usually formed 2-3 weeks after the fracture, when the bone tissue is destroyed and the periosteum and surrounding soft tissues are also damaged and torn, accompanied by a large amount of bleeding, filling the tissues in and around the fracture ends to form hematoma. The hematoma usually coagulates within a few hours, along with some inflammatory cell infiltration. The hematoma gradually mechanizes to form granulation tissue, which further develops into fibrous connective tissue; 2. Bone scab formation period: usually 4-8 weeks, including two processes, fibrous bone scab formation period and bony bone scab formation period. Within 2-3 days of the fracture, the fibroblasts and capillaries of the endosteal and eposteal membranes proliferate into the hematoma and promote the transformation of the hematoma into a fibrous bone scab. As the fracture healing progresses, the osteocytes produce new bone, which gradually replaces the fibrous bone scab, resulting in the formation of some bone-like tissue and the formation of a bony scab. The cartilaginous tissue within the fibrous scab will also gradually transform into bone tissue as calcium salts are deposited, participating in the formation of the bony scab. However, these structures are not dense enough, and the arrangement of bone trabeculae is confusing, which cannot meet the requirements of normal function; 3. Bone scab remodeling period: usually 2-4 years, mainly refers to the gradual connection of the irregularly arranged bony scabs at the broken end of the bone fracture. In order to meet the physiological requirements and achieve gradually firm structure and function, the bony scab will further become mature lamellar bone and cortical bone, and the normal relationship with the medullary cavity will be restored, and the medullary cavity will be reopened, and complete healing of the fracture will be achieved.