The healing process of fractures is characterized by the simultaneous removal of damage and new repair and is susceptible to the influence of many factors. There are both favorable and unfavorable factors. The favorable factors can promote the healing of fracture and shorten the treatment time, while the unfavorable factors can delay the healing of bone and even lead to bone disjunction or re-fracture.
Systemic factors
1. Age The rate of fracture healing varies at different ages. Femoral fractures in newborns heal strongly in 2 weeks, while in adults it usually takes 3 months.
2. Health status Patients with poor health conditions, such as osteoporosis, diabetes, malnutrition, malignancy and other chronic wasting diseases, require longer healing time after fracture.
3. Bad habits Smoking, alcoholism and other bad habits can also cause significant prolongation of fracture healing and even lead to bone non-union or femoral head necrosis.
Local factors
1. Fracture type Oblique or spiral fracture, the contact surface of the fracture is larger than the transverse fracture, so the fracture heals faster in the former.
2. Blood supply to the fracture site The blood supply to the fracture segment varies depending on the site of the fracture, and there are generally four conditions.
(1) The blood supply to both fracture segments is good, mostly seen in epiphyseal fractures. The epiphysis is mostly attached to the joint capsule, ligaments and tendons, and many small blood vessels enter the bone, so the blood supply is abundant and the fracture heals quickly, such as tibial plateau fracture and femoral condyle fracture.
(2) A fracture segment has a poor blood supply, such as a fracture of the middle and lower 1/3 of the tibial stem, because the tibial stem is mainly supplied with blood from the top down by the trophoid artery that enters the medullary cavity posteriorly in the upper 1/3 of it. After the fracture, the trophoid artery is dissected and the distal fracture segment is maintained only by small subperiosteal vessels, which significantly reduces the blood supply and slows fracture healing.
(3) The blood supply to both fracture segments is poor, for example, if the fracture occurs at the same time in the upper and lower middle tibia, only one fracture segment of the upper segment has poor blood supply, while the lower segment has poor blood supply to both segments, so the upper segment fracture heals faster than the lower segment.
(4) Complete loss of blood supply to the fractured segment. If the femoral neck is intracapsularly fractured, the blood supply to the femoral head is almost completely interrupted and ischemic necrosis is likely to occur.
3. Degree of soft tissue injury
4. Soft tissue embedding If there is muscle, tendon and other tissues embedded between the two fracture ends, it not only affects the fracture repositioning, but also hinders the alignment and contact of the two fracture ends, and the fracture is difficult to heal or even does not heal.
5. Infection Open fracture, local infection can lead to septic osteomyelitis, soft tissue necrosis and dead bone formation, which seriously affects fracture healing.
Improper treatment
1. Repeated manual repositioning can damage local soft tissues and bone epithelium, which is not conducive to fracture healing. Although manual repositioning can less affect the blood flow of the fracture, it is often difficult to achieve anatomical repositioning, so any person who has reached the standard of functional repositioning should not be repositioned.
2. In incisional repositioning, excessive stripping of soft tissues and periosteum may affect the blood supply of the fracture segment, which may lead to delayed healing or even non-healing of the fracture. In addition to mastering strict surgical indications, the local blood supply should be disturbed and destroyed as little as possible during surgery.
3. Excessive removal of bone fragments during open fracture debridement may cause delayed healing or non-healing of the fracture.
4. When continuous bone traction treatment is performed for a fracture, the traction force is too large, which can cause separation of the fracture segment, and the local blood supply is insufficient due to vascular spasm, which can affect the fracture healing.
5. When the fracture is not firmly fixed, the fracture may be affected by continuous shear and rotational forces, which may interfere with the growth of bone scabs and vascularization, resulting in delayed healing or non-healing of the fracture.
6. Premature or inappropriate functional exercise can hinder the firmness of fracture fixation and thus affect fracture healing. While correct and appropriate functional exercise can promote blood circulation of the limb, eliminate swelling; promote bone scab growth; prevent muscle atrophy, osteoporosis and joint stiffness, and facilitate the recovery of joint function.