Fracture recovery process, these four stages are worth knowing

For people with fractures, the occurrence of fractures will undoubtedly cause damage to their normal bone and joint functions, and in the recovery process, it also takes a period of time to completely heal. So, what are the recovery processes of fractures?

(I) Impact period

From the moment of force application until the energy is eliminated, the time is short. The degree of damage to bones and surrounding soft tissues is closely related to the amount of energy absorbed. The higher the energy and the higher the speed, the more severe the fracture.

(II) Induction Period

The main manifestation is hematoma formation, necrosis of bone cells at the fracture end, damaged periosteum and surrounding cells. After a fracture, the nutrient arteries of the bone and its branches and surrounding muscles are torn. There are varying degrees of bleeding, the severity of which is related to the fracture type, bone volume, anatomical location and displacement. Bleeding can extravasate to form hematomas, and the amount of bleeding is often underestimated. In severe cases, such as long bone shafts and pelvis, hypovolemic traumatic shock can be caused. After the death of cells at the fracture end, the oxygen partial pressure in the hematoma decreases and the acidity increases. The local area contains kinins, prostaglandins and non-collagenous proteins, and releases a variety of cytokines.

(III) Inflammatory stage

It starts early after injury and lasts until chondrocytes and osteocytes appear. The local inflammatory response is manifested by vascular dilation, plasma infiltration, edema, and infiltration of inflammatory cells, including neutrophils, mast cells, and macrophages. Osteoclasts begin to remove dead bone. The fibrin network in the hematoma is invaded by new blood vessels, and a large number of mesenchymal cells proliferate around the invasion of blood vessels and differentiate into fibroblasts and phagocytes. As the red blood cells in the hematoma are destroyed and fibrin infiltrates, the hematoma is gradually cleared and replaced by a loose network of fibrin, reticular fibers, and collagen fibers, which quickly organize into granulation tissue and then form a fibrous callus.

(IV) Soft callus stage

The hematoma has been organized, the fracture end is full of cellular components, and there are obvious new blood vessels. Osteoclasts continue to remove the remaining dead bone. New bone is formed under the periosteum near the fracture end, and chondrocytes begin to appear in the gap between the fracture ends, replacing the fibrovascular stroma with cartilage-like tissue.