What are the fracture healing stages?

Fracture healing is a complex and continuous process, usually including hematoma formation, fibrous callus formation, bony callus formation and callus remodeling or remodeling stages. 1. Hematoma formation After fracture occurs, there will be a lot of bleeding around the fracture end, forming hematoma. This stage is mainly to initiate inflammatory reaction, preparing for the subsequent repair process. Hematoma can play a role in temporary fixation of fracture ends, while the blood cells and inflammatory cells in it will release a variety of cytokines and growth factors to promote the initiation of the repair process. In this stage, fibroblasts proliferate and differentiate in large numbers, secreting collagen and other matrix, forming preliminary connecting structure. Fibrous callus has certain strength, but it is not enough to withstand greater stress. This stage involves the active role of osteoblasts, which synthesize and secrete bone matrix and promote mineralization. The formation of bony callus makes the fracture ends more firmly connected, but the bone tissue has not fully recovered to normal structure and performance at this time. 4. Callus remodeling or remodeling In the late stage of fracture healing, the bony callus will be remodeled and reshaped according to the activity and stress of the limbs. The excess callus will be absorbed, and the arrangement of the trabecular bone will gradually adapt to the mechanical requirements, so that the structure and function of the bone will gradually return to the state before the fracture. This process can take a long time, even years after the fracture has healed.