Femoral head necrosis

　　Avascular necrosis of the femoral head refers to the microcirculatory obstruction of the femoral head caused by various reasons, leading to the death of viable bone cells in the femoral head. If not treated in time, it will lead to the formation of bone空洞 in the femoral head, even fracturing, collapsing, and osteosclerosis at the edge of the acetabulum, and other pathological changes. Although the causes are different, their common pathological manifestation is ischemia of the femoral head, and the generally accepted theory is that the blood supply is blocked.

　　1. Trauma.Fractures of the femoral neck, sprains, falls, hip dislocation, and dysplasia of the acetabulum are prone to avascular necrosis of the femoral head, with an incidence rate of generally 75%-95%, and most of them can develop osteonecrosis after fracture surgery. Hip injuries (including hip dislocation, fracture of the femoral neck, and intertrochanteric fracture, etc.) directly affect the local blood supply, especially the insufficient blood supply to the femoral head, leading to avascular necrosis of the femoral head. Hip dislocation combined with fracture has a high necrosis rate of up to 90%. If the fracture dislocation is not reduced within 24 hours, the femoral head will have a 100% chance of necrosis.

　　2. Hormonal drugs.Long-term and excessive use of adrenocorticosteroids (such as prednisone, dexamethasone, etc.) can cause osteoporosis and arterial obstruction, leading to the gradual necrosis of bone cells and marrow cells.

　　3. Rheumatism.More than half occur in cold and damp climates. Experts in the treatment of femoral head necrosis in China introduce that it is widely prevalent, less common in the south, and gradually more common towards the north, often occurring with ankylosing spondylitis and rheumatoid arthritis.

　　4. Abnormal syringomyelia.The causes of bone necrosis are as follows: ①Injuries ②Viral influenza fever ③Other diseases, such as meningitis. In clinical practice, there are cases of syringomyelia, weakness in walking, muscle atrophy, and increased pain in both hip joints, which may lead to bone necrosis.

　　5. Osteoporosis.Because the internal structure of the bone tissue changes, part of the trabeculae are damaged, and the blood circulation of the bone is obstructed, making avascular necrosis of the femoral head more likely to occur.

　　6. Congenital maldevelopment of the acetabulum and flat hips.Due to the maldevelopment of the acetabulum, the head and acetabulum are asymmetric, causing abnormal distribution of stress on the femur. Long-term stress leads to acetabular necrosis.

　　7. Chronic alcohol intoxication.Alcohol intoxication can lead to abnormal lipid metabolism. Clinical data confirms that long-term heavy drinkers have a significantly higher rate of avascular necrosis of the femoral head. The reason is that alcohol can increase blood viscosity, causing microcirculatory obstruction in the bone and leading to necrosis.

　　8. Kidney and liver deficiency.Mostly related to age, and also related to kidney and liver deficiency caused by internal medicine or surgery diseases during the treatment process. It is more common after the age of 40.

　　9. Bone tuberculosis.Because the bone tissue is eroded by tuberculosis bacilli, part of the acetabulum and femoral head undergoes cystic changes, making the femoral head prone to a mushroom-like change, collapse, and functional impairment, which easily leads to avascular necrosis of the femoral head.

　　10. Bone malnutrition.Due to long-term poor diet, the intake of calcium and phosphorus is insufficient, which cannot meet the needs of bone tissue for metabolism and growth, leading to circulation obstruction. The femoral head may undergo necrosis due to insufficient blood supply.

　　Traditional Chinese medicine believes that the liver, spleen, and kidney are the three internal organs most closely related to avascular necrosis of the femoral head. The kidney is the root of the vital essence, responsible for bone and marrow formation. When the kidney is healthy, the marrow is full, and the bone becomes firm. Conversely, the marrow dries up and the bone withers, losing the ability to regenerate. The liver governs the tendons and stores blood, sharing the same origin with the kidney. The prosperity or decline of both organs is interrelated. If the liver is affected, the storage and regulation of blood volume are impaired, 'The heart governs blood, stored by the liver, and it flows through all meridians when people are active, and returns to the liver when people are at rest.' If the storage and circulation of blood are not proper, and nutrition is insufficient, it is also an important factor in the occurrence of ischemic avascular necrosis of the femoral head. The spleen and stomach are the root of the postnatal essence, the source of the production and transformation of all things. When the spleen is healthy and the stomach harmonious, grains are properly digested, Qi and blood are transformed, and nutrients are distributed to the limbs and organs. If the spleen and stomach are not functioning properly, the source of Qi and blood transformation is lacking, and the tendons, bones, muscles, and flesh all lack Qi to sustain them.

　　Femoral head necrosis is a complex pathological process. If it is not treated promptly and effectively in the early stage, it will lead to femoral head collapse, narrowing of the joint space, leading to osteoarthritis, hip joint dysfunction, and finally causing disability and paralysis in patients. With the treatment of femoral head necrosis, some other complications often occur, so patients should take scientific and effective preventive measures.

　　Complications of femoral head necrosis: postoperative pain, limited activity, acetabular wear, prosthesis fracture, prosthetic limb infection, bone cortex penetration, fracture of the femoral neck during surgery, fat embolism, and ischemic necrosis of the femoral head. If the disease is not treated promptly and effectively in the early stage, it will lead to femoral head collapse, narrowing of the joint space, resulting in osteoarthritis, hip joint dysfunction, and finally leading to disability and paralysis in patients. With the treatment of femoral head necrosis, some other complications often occur, so patients should take scientific and effective preventive measures.

　　The main symptoms of femoral head necrosis are reflected in the following five points:

　　1. Pain. Pain can be intermittent or continuous, exacerbated by walking and activity, and sometimes rest pain. Pain is often of a needle-like, dull, or aching discomfort, often radiating to the inguinal region, the inner side of the thigh, the posterior side of the buttocks, and the inner side of the knee, with numbness in the area.

　　2. Joint stiffness and limited movement. The affected hip joint is not flexible in flexion and extension, difficult to squat, unable to stand for a long time, and walk with a duck-like gait. Early symptoms are marked limited abduction and external rotation movements.

　　3. Limping. It is a progressive shortening limping caused by hip pain and femoral head collapse, or hip joint subluxation in the late stage. Early symptoms often present with intermittent limping, and it is more obvious in children.

　　4. Signs. Local deep pressure pain, pain at the insertion point of the adductor muscles, positive 4-letter test, positive Gauguin sign, positive Alis sign, positive TKdele test. Limited abduction, external rotation, or internal rotation, the affected limb may be shortened, muscle atrophy, and even have signs of subluxation. Sometimes there is positive axial pain.

　　5. X-ray manifestations. Fine or interrupted trabeculae, femoral head cysts, hardening, flattening, or collapse.

　　Femoral head necrosis, also known as aseptic necrosis and ischemic necrosis of the femoral head, the symptoms of each stage are as follows: Early symptoms include: lumbar pain, pain in the affected hip, pain in the affected inguinal region, pain in the affected knee joint, aversion to cold in the affected limb, weakness during active movement, soreness, and fatigue. In the middle stage of femoral head necrosis, symptoms are very obvious, mainly limping, walking pain, and functional impairment. When taking an X-ray, most of the trabeculae will be disappeared, cystic changes, bone hardening, and cartilage fracture and collapse of the femoral head. In the late stage of femoral head necrosis, the limping is more severe, and the patient will feel significantly shorter legs, difficulty in walking, pain, and the X-ray will show a flattened and collapsed femoral head, narrowing or disappearance of the joint space, obvious cystic changes, a larger area of bone hardening, complete fracture of the femoral head cartilage, and rough joint surface.

　　Prevention of femoral head necrosis:

　　1. It is imperative to strengthen the self-protection awareness of the hip.

　　2. Pay attention to your feet while walking and be careful of tripping, especially when walking on icy and snowy ground in winter.

　　3. Before engaging in sports, it is necessary to fully prepare the hip with warm-up exercises, feeling the body warm up, and ensuring the limbs are flexible.

　　Four, When carrying or lifting heavy objects, try to avoid hip扭伤, and try not to do heavy work.

　　Five, Immediate treatment should be sought after hip injury, and it is absolutely not allowed to walk too much while the injury is not healed, in order to avoid repeated injury to the hip joint.

　　Six, Try not to use or use less hormone drugs in the treatment of certain diseases, especially some pain diseases.

　　Seven, Try not to develop the habit of long-term heavy drinking.

　　Eight, For femoral neck fractures, strong internal fixation should be used, and vascularized bone flap head transplantation should be performed at the same time to promote the healing of the femoral neck, increase blood supply to the head, prevent osteonecrosis, and follow up regularly after surgery. Oral traditional Chinese medicine and calcium supplements to promote blood circulation should be taken appropriately to prevent the occurrence of femoral head ischemia.

　　Nine, When it is necessary to use hormones for related diseases, the principle of short-term and moderate use should be followed, and vasodilator drugs, vitamin D, calcium, and other supplements should be taken in combination. Do not arbitrarily and excessively use hormone drugs without listening to medical advice.

　　Ten, It is necessary to change the bad habit of long-term heavy drinking or to quit drinking, to detach from the contact environment of pathogenic factors, to eliminate the chemical toxicity of alcohol, and to prevent tissue absorption.

　　Laboratory examination for osteonecrosis of the femoral head:

　　Osteonecrosis of the femoral head can be diagnosed by asking medical history, clinical examination, X-ray films, magnetic resonance imaging (MRI), radionuclide scanning, and computerized tomography (CT).

　　One, Clinical Diagnosis: A thorough medical history should be taken, including history of hip trauma, corticosteroid use, alcohol consumption, or anemia. The clinical symptoms should include the location, nature, and relationship with weight-bearing. The physical examination should include the rotation activity of the hip joint.

　　Two, X-ray Film: X-ray films are difficult to diagnose early (stage 0, I) ONFH, but can show positive changes in lesions above stage II, such as hardening bands, radiolucent cystic changes, speckled ossification, subchondral fractures, and femoral head collapse. It is recommended to take X-ray films of both hips in the posterior-anterior (anteroposterior) and frog lateral positions, as the latter can more clearly show the changes in the necrotic area of the femoral head.

　　Three, MRI: The T1-weighted phase of typical ONFH shows residual epiphysial line of the femoral head, winding band-like hypointensity areas adjacent or crossing the epiphysial line, and low signal bands surrounding high signal areas or mixed signal areas. The T2-weighted phase may show a double-line sign.

　　Four, Radionuclide Scanning: Radionuclide scanning has high sensitivity but low specificity in diagnosing early ONFH. The diagnosis can be confirmed if there is a cold area in the hot area during the 99mTc diphosphate scan. However, the simple radionuclide concentration (hot area) should be differentiated from other hip joint diseases. This examination can be used for screening lesions and searching for multiple necrotic foci. Single Photon Emission Computed Tomography (SPECT) can enhance sensitivity, but specificity remains low.

　　Five, CT imaging can clearly show the boundaries, areas, hardening bands, spontaneous repair, and subchondral bone of necrotic foci in II and III stage lesions. The clarity and positive rate of CT in showing subchondral fractures are superior to MRI and X-ray films. The addition of two-dimensional reconstruction can display the overall situation of the femoral head in the coronal position. CT scanning is helpful in determining the focus of the lesion and selecting the treatment method.

　　Dietary health care for ONFH patients:

　　ONFH patients should eat dairy products every day and often 'bask in the sun', ensuring about 1 hour of 'basking in the sun' each day, which will produce better results.

　　When heating milk, it needs to be stirred continuously to prevent the precipitation of calcium phosphate, causing a loss of calcium and phosphorus; when milk is eaten at the same time as foods containing phytic acid, oxalic acid, and dietary fiber, the absorption of calcium is reduced, so milk should not be eaten with spinach, nor should it be drunk with strong tea. To further increase the absorption of calcium and phosphorus in milk, vitamin A and vitamin D can be added to make 'compound milk'. Or add cod liver oil (which contains a large amount of vitamin A and vitamin D) to ordinary milk, or take vitamin A and vitamin D to promote the absorption of calcium and phosphorus.

　　Another food containing a lot of calcium is animal bone soup. Moreover, bone soup contains fatty acids and proteins, including saturated fatty acids and unsaturated fatty acids. Proteins, lipids, calcium, and other substances are important substances for bone formation, so drinking bone soup can also help treat avascular necrosis of the femoral head. However, there are fewer calcium ions in bone soup, and the concentration of calcium is low, so it is necessary to break the bones first when making soup to increase the solubility rate of minerals and proteins.

　　In seafood such as fish and shrimp, there is a lot of calcium and phosphorus, and the ratio of calcium to phosphorus is reasonable, which is a high-quality source of calcium and phosphorus. Therefore, eating more seafood is very beneficial for ONFH patients. When eating fish and shrimp, choose appropriate cooking methods, eat the shell together, because these components contain more calcium.

　　Western treatment methods for avascular necrosis of the femoral head:

　　At present, there is no method that can cure ONFH of different types, stages, and different necrotic volumes. Formulating a reasonable treatment plan should comprehensively consider staging, necrotic volume, joint function, and patient age, occupation, etc.

　　Non-surgical treatment for avascular necrosis of the femoral head: It should be noted that the efficacy of non-surgical treatment for ONFH is still unpredictable.

　　One, protective weight-bearing: There is still controversy in the academic community on whether this method can reduce femoral head collapse. Using crutches can effectively reduce pain, but it is not recommended to use wheelchairs.

　　Two, drug treatment is suitable for early stage (0, I, II) ONFH, and non-steroidal anti-inflammatory analgesics can be used. For hypercoagulable and low fibrinolytic states, low molecular weight heparin and corresponding traditional Chinese medicine treatment can be used. Alendronate sodium can prevent femoral head collapse, and vasodilator drugs also have certain efficacy.

　　Three, physical therapy includes extracorporeal shock wave, high-frequency electric field, hyperbaric oxygen, magnetotherapy, etc., which is beneficial for pain relief and promoting bone repair.

　　Surgical treatment for avascular necrosis of the femoral head: Most ONFH patients will face surgical treatment, which includes two major categories: preserving the patient's own femoral head surgery and artificial hip joint replacement. Preserving the femoral head surgery includes core decompression, bone grafting, osteotomy, etc., which is suitable for ARCO I, II, and III early stages, with necrotic volume above 15% in ONFH patients. If the method is appropriate, it can avoid or delay the artificial joint replacement.

　　1. Core decompression of the femoral head (core decompression) It is recommended to use a thin needle with a diameter of about 3mm, and make multiple holes under fluoroscopic guidance. This therapy can be combined with autologous bone marrow cell transplantation, BMP implantation, and others. This therapy should not be used in the late stage (stage III, stage IV).

　　2. Vascularized autologous bone grafting Commonly used methods include vascularized fibula grafting, vascularized iliac bone grafting, and others, which are suitable for stage II and III ONFH. If used appropriately, the efficacy is good. However, this type of surgery may lead to donor site complications, and the surgery has a large trauma, long operation time, and large differences in efficacy.

　　3. Avascular bone grafting Commonly used methods include avascular intertrochanteric decompression bone grafting, avascular femoral head neck lamp-shaped decompression bone grafting, and others. Bone grafting methods include compression bone grafting, support bone grafting, and others. The bone grafting materials used include autologous cancellous bone, allograft bone, and bone substitute materials. This type of surgery is suitable for stage II and early stage III ONFH, and if used appropriately, the mid-term efficacy is good.

　　4. Osteotomy The necrotic area is moved out of the weight-bearing area of the femoral head, and the non-necrotic area is moved out of the weight-bearing area. Osteotomy methods used in clinical practice include varus or valgus osteotomy, intertrochanteric rotational osteotomy, and others. This method is suitable for stage II or early to middle stage III ONFH with moderate necrotic volume. This surgical method will bring great technical difficulty for future artificial joint replacement.

　　5. Artificial joint replacement Once the femoral head collapses severely (late stage III, stage IV, stage V), if there is significant joint function or pain, artificial joint replacement should be chosen. For patients under 50 years old, surface replacement can be selected, which can preserve more bone for future revision surgery, but each has its indications, technical requirements, and complications, and should be chosen with caution.