The fracture healing process is divided into four main phases: first, the hematoma inflammation mechanization phase, in this period the fracture end bleeds to form a hematoma, later the hematoma mechanization, gradually evolve into fibrous tissue, thus connecting the fracture end, this period ends in about 2 weeks. During this period, the fibrous connection of the fracture ends gradually evolves into the original bone scab, the fracture ends are relatively stable, and the fracture line will be blurred when the film is taken, which takes 4-8 weeks. During this period, the fracture scab gradually evolves into a mature fracture scab, which makes the fracture line gradually blurred and the fracture end gradually stabilized. Fourth, the fracture shaping period, this time is mainly the original bone scab gradually mature into normal bone, excess bone scab will be gradually absorbed by osteoclasts, so that the fracture site bone shaping success, it takes 1-2 years.