With the rapid development of transportation and construction, the incidence of femoral neck fracture in young people has increased significantly. At present, most medical technologies can achieve anatomical reduction (it can be said that it can achieve' suture'), and fractures can heal quickly, but there are always some patients with femoral head necrosis after fracture healing. They are very confused and often go to the clinic or ward for consultation: "The bones have grown out, why is the femoral head still necrotic?" Psychological pressure is great. Because of the necrosis of the femoral head, it was once called "immortal cancer", and many people finally had to do artificial joint replacement.
Most people are familiar with aseptic ischemic necrosis of femoral head. After the femoral neck fracture, the attending doctor or attending doctor communicates with the patient and their families, emphasizing the possibility of femoral head necrosis at most.
Femoral neck fracture is prone to necrosis of femoral head, which is directly related to the particularity of blood supply of femoral head. Because of its arterial blood supply, the femoral head lacks rich collateral circulation, and the displaced femoral neck fracture can also cause vascular injury, which often leads to ischemic necrosis of the femoral head.
Femoral neck fractures mostly occur in the elderly. With the extension of human life, its incidence rate is getting higher and higher, especially the aging population, which has become a serious social problem. There are two major problems in clinical treatment: nonunion of fracture and avascular necrosis of femoral head.
Can the probability of femoral head necrosis be roughly predicted? Generally speaking, the following principles can be followed to estimate the possibility of avascular necrosis of femoral head after femoral neck fracture: the necrosis rate is inversely proportional to age: the younger the general age, the higher the necrosis rate, that is, the necrosis rate of femoral head in children and young people is higher than that in the elderly. Because the violence leading to femoral neck fracture in children and adolescents is generally greater, the displacement of fracture end is generally more serious, and the blood supply damage is also heavier.
With the prolonged treatment time of femoral neck fracture, the incidence of ischemic necrosis also increases, so once the preoperative preparation of femoral neck fracture is perfect, surgery should be performed as soon as possible.
Influence of fracture line position: The closer the fracture line position is to the femoral head, the higher the necrosis rate of the femoral head, and the subcephalic type is significantly higher than the basal type. The linear necrosis rate of posterior superior oblique fracture of femoral neck is the highest. Femoral neck fracture is seriously displaced, and the incidence of femoral head necrosis is high. Poor reduction, repeated and rough manual reduction will also increase the necrosis rate.
How to judge the occurrence of femoral head necrosis by yourself? X-rays should be taken every three months as usual after operation 1 year, and it is best to hold crutches before fracture healing. On this basis, review once every six months and observe continuously for at least 3 years. When joint pain occurs again after fracture healing, we should attach great importance to it, see a doctor in time, and carry out X-ray, MRI or ECT examination to achieve timely detection, early diagnosis and early treatment.
Why does femoral neck fracture lead to femoral head necrosis? The probability of femoral head necrosis caused by femoral neck fracture is about 20-40%. The pathological changes after the femoral neck fracture are as follows: One week after the femoral neck fracture, there was a large area of bleeding in the bone marrow in the femur, and the sinus cavity of the bone marrow expanded, but the bone cells did not atrophy for the time being.
Three weeks after femoral neck fracture, bone marrow cells decreased obviously, fat cells increased and deformed, and bone cells shrank at this time; After 6 weeks of femoral neck fracture, bone marrow cells decreased obviously, fat cells were necrotic, some trabecular bones showed cavities and lacunae, osteoblasts appeared on the surface of trabecular bones, and bone marrow showed fibrous changes.
Three months after the femoral neck fracture, the trabecular bone became thicker, and the necrotic trabecular bone was surrounded by layered new trabecular bone. Six months after the fracture, hyperplastic fibrous tissue appeared around the necrotic area, and some patients had trabecular necrosis or loss, and a large number of osteoblasts could be seen.
After femoral neck fracture, microthrombosis was found in femoral head blood vessels, which was relatively less in arteries and more in veins. These microthrombosis will partially or even completely block blood vessels, leading to vicious circle and femoral head ischemia.
Femoral neck fracture causes avascular necrosis of femoral head, which changes greatly with time. However, there are two common pathological changes of femoral head necrosis, one is segmental necrosis in weight-bearing area, which eventually leads to clinical avascular necrosis of femoral head, and the other is idiopathic focal necrosis, which shows osteoporosis on X-ray film, but has abnormal signals on MRI.
In order to prevent femoral head necrosis after femoral neck fracture, the following measures can be taken: To avoid or reduce complications, patients should be instructed to exercise their whole body muscles and joint functions purposefully and planned, and on the basis of active activities, they can promote fracture healing, restore limb function and enhance body resistance, so they are called self-exercise.
Movement of affected limb: After fracture, the affected limb is often in a completely relaxed state due to the effects of pain, traction and instruments, which affects the muscle strength and joint activity of the affected limb, often leading to muscle atrophy, muscle strength decline, joint stiffness and venous thrombosis, which is not conducive to fracture healing and swelling elimination.
Therefore, the affected limbs should be treated one by one according to the active contraction of muscles, the active flexion and extension of each joint and the passive activity and smoothness of hip joint, and the number of regular exercises should be gradually increased according to the patient's situation. The correct exercise method can produce mechanical stimulation to the fracture end, which is beneficial to callus growth.
Exercise the whole body and healthy limbs, and exercise the muscles and joint functions of the whole body. You can use three or five points to support the upper body and buttocks, and the healthy lower limbs can be lifted with straight legs. You can exercise on the bed with simple fitness equipment, increase the muscle strength of the whole body, prevent disuse muscle atrophy, lift your hips, reduce the compression time, avoid bedsores, actively stretch at various joint parts, and prevent joint stiffness. Chest enlargement and deep breathing can increase vital capacity and avoid falling pneumonia. The above exercises can be strengthened step by step according to the patient's condition.