Depending on the time of the fracture and the different healing criteria, the formation of bone scab varies and is generally categorized as primary and osteogenic scab. Primary bone scab mainly appears in the early stage and will appear 3-4 weeks after the fracture. This is due to the fracture bleeding, the formation of hematoma tissue, after 2-3 weeks of hematoma tissue mechanization, the formation of fibrous tissue, and then in the osteoblasts to modify the fibrous tissue, the fracture end of the gradual growth of the original bone scab. At this time, the fracture line can be seen blurred in the X-ray film. In addition, the gradual growth from the primitive bone scab to the osteogenic bone scab takes another 4-8 weeks. The osteogenic scab is very stable compared to the primitive scab. At this point, the patient can start doing heavy work or strenuous exercise. Imaging is required to determine if the fracture has healed, and patients should be reviewed regularly until they notice the fracture line fading away. The formation and rebuilding of the bone scab is very important and may take a total of 1-2 years, so healing tissue is formed throughout the fracture healing process.