What are the processes of fracture healing?

Fractures are common in life, especially for the elderly, who often suffer from osteoporosis. When the weather is cold, if you are not careful, you may fall and break a bone. In addition, for young people, if they are hit hard at work, they may also suffer a fracture. When a fracture occurs, it must be treated in time. It takes a certain amount of time to heal. As the saying goes, it takes a hundred days to heal a broken bone. Therefore, during the treatment and recovery period, you must do a good job of health care, eat more foods that help supplement calcium, and get enough rest. When the fracture enters the recovery period, you should actively exercise, which will help to restore your health.

1. Impact period

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

(II) Induction period

The main manifestations are hematoma formation, necrosis of bone cells at the fracture ends, damaged periosteum and surrounding cells. After a fracture, the bone's nutrient arteries and their branches and surrounding muscles are torn. There are varying degrees of bleeding, the severity of which depends on the fracture type, bone volume, anatomical location, and displacement

(III) Inflammatory phase

It begins early after injury and continues until chondrocytes and osteocytes appear. The local inflammatory response is manifested by vasodilation, plasma exudation, edema and infiltration of inflammatory cells, including neutrophils, mast cells and macrophages, and osteoclasts begin to clear dead bone.

(IV) Soft callus stage

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

(V) Hard callus stage

After a fracture, the periosteum and endosteum near the broken ends begin to proliferate and thicken. There is also blood vessel invasion, and bone is formed by intramembranous ossification. On the other hand, between the fracture ends and under the lifted periosteum, most of the fibrovascular granulation tissue formed by the organization of the hematoma is transformed into cartilage, and bone is formed by endochondral ossification. Chondrocytes form bone through proliferation, hypertrophy, degeneration, and ossification.

6. Shaping and Reconstruction Period

Regenerated bone is constantly remodeled according to mechanical principles and the needs of the human body. That is, osteoclasts are constantly absorbing and osteoblasts are forming new bone. If the fracture is well aligned, the fracture site can be completely restored to its original shape, the medullary cavity can be unobstructed again, and no trace of fracture will be left. Even if there is slight migration and angular deformity, it can be completely corrected, especially in children and adolescent patients. The defect on the concave side can be supplemented by intramembranous ossification, and the excess bone on the convex side is absorbed to adapt to the local load. However, this reconstruction has its limits, and severe deformities will be difficult to completely correct.

Healing standardsEdit

1. No local tenderness or longitudinal percussion pain;

2. No abnormal activity in the local area;

3. X-rays show that the fracture line is blurred, with continuous callus passing through the fracture line;

4. Functional assessment: when external fixation is removed, the upper limbs can hold 1 kg horizontally for several minutes, and the lower limbs can walk continuously for 3 minutes without movement, not less than 30 steps;

5. If the fracture site does not deform after 2 consecutive weeks of observation, the first day of observation is the date of clinical healing. The measurements of items 2 and 4 must be made carefully, with the principle of preventing deformation or re-fracture.