Avascular necrosis (AVN), also known as osteonecrosis, aseptic necrosis, ischemic bone necrosis, or bone infarction, is a condition in which bone tissue dies because of an inadequate blood supply. Bones require a continuous supply of blood to remain healthy and strong. When the blood supply to a part of a bone is reduced or completely interrupted, the bone tissue may gradually die. Over time, the affected bone can become weak, develop tiny fractures, and eventually collapse. AVN most commonly affects the hip, particularly the head of the femur (the upper part of the thigh bone). However, it can also affect other bones and joints, including the knee, shoulder, wrist, ankle, hands, and feet. The condition may develop slowly and may not cause symptoms during its early stages. As the disease progresses and the bone becomes damaged, pain and difficulty using the affected joint may develop. Early diagnosis and treatment are important because treatment may be more effective before the affected bone collapses.
In the early stages, avascular necrosis may cause no symptoms. Some people may only discover the condition during imaging tests performed for another reason. As the condition progresses, the most common symptom is pain in the affected joint.
Avascular necrosis develops when the blood supply to a bone is interrupted or reduced. Without enough oxygen and nutrients, bone cells begin to die. The loss of blood supply may occur because of an injury, blockage of blood vessels, increased pressure inside the bone, or certain diseases and medications.
Taking high doses of corticosteroid medicines for a prolonged period can increase the risk of avascular necrosis. Corticosteroids are used to treat several inflammatory and autoimmune conditions. However, long-term use may affect fat metabolism and blood circulation within the bone. Not everyone taking corticosteroids develops AVN, but the risk may increase with higher doses and prolonged treatment.
Excessive alcoholism is associated with an increased risk of AVN. Heavy alcohol consumption may contribute to changes in fat metabolism and may interfere with the normal blood supply to bone tissue.
Smoking can damage blood vessels and reduce circulation. Poor blood circulation may contribute to bone damage and may increase the risk of complications or poor healing.
Early AVN can be difficult to diagnose because symptoms may be mild or absent. A doctor will usually consider the person’s symptoms, medical history, medications, previous injuries, and risk factors.
The doctor may examine the affected joint and check for:
Pain
Tenderness
Reduced movement
Joint stiffness
Difficulty bearing weight
X-Ray- An X-ray may help identify changes in the bone during later stages of the disease. However, early AVN may not always be visible on a standard X-ray.
Magnetic Resonance Imaging (MRI)- An MRI scan is one of the most useful tests for detecting AVN at an early stage. MRI can identify changes in bone tissue before significant damage becomes visible on an X-ray.
CT Scan- A CT scan may provide detailed images of the bone and may help assess structural damage or bone collapse.
Bone Scan- In certain situations, a bone scan may be used to identify areas of abnormal bone activity.
Early Stage- Blood supply to the bone becomes impaired, but the shape of the bone may still be preserved. Symptoms may be absent or mild.
Progressive Bone Damage- Bone tissue begins to weaken and structural changes may develop. Pain may become more noticeable.
Bone Collapse- Tiny fractures may develop in the weakened bone, eventually causing the surface of the bone to collapse.
Joint Damage- After bone collapse, the joint surface may become severely damaged and arthritis may develop. The stage of AVN is important because treatment options and outcomes may depend on how much damage has already occurred.
Physical therapy may help maintain joint movement and strengthen the muscles surrounding the affected joint. However, exercises should be performed according to medical advice, especially when the affected bone is at risk of collapse.
Core decompression involves removing a small portion of bone from the affected area. The procedure may help reduce pressure inside the bone and encourage the development of new blood vessels. This procedure may be more beneficial during the earlier stages of AVN, before significant bone collapse occurs.
A bone graft may be used to support damaged bone and help repair the affected area. In some cases, specialized procedures may use vascularized bone grafts that bring their own blood supply.
An osteotomy involves changing the position or alignment of the bone to reduce stress on the damaged area. This procedure may be considered in selected cases.
If the bone has severely collapsed and the joint is significantly damaged, joint replacement surgery may be necessary. For severe AVN of the hip, a hip replacement may be recommended to relieve pain and improve mobility.
Not every case of AVN can be prevented, especially when it occurs because of an injury or certain medical conditions. However, reducing modifiable risk factors may help lower the risk.
You should seek medical advice if you experience persistent or unexplained pain in a joint, particularly the hip, knee, or shoulder. Medical attention is especially important if you:
Have persistent hip or groin pain
Experience increasing difficulty walking
Have pain while putting weight on a joint
Have a history of significant joint injury
Use corticosteroids for a long period
Have sickle cell disease or another condition associated with AVN
Early diagnosis may help identify the condition before significant bone collapse occurs.
Avascular necrosis (AVN) is a condition in which bone tissue dies because its blood supply is reduced or interrupted. It is also called osteonecrosis, aseptic necrosis, ischemic bone necrosis, or bone infarction. If untreated or progressive, the weakened bone can develop fractures and eventually collapse.
Early AVN may cause no symptoms. When symptoms begin, pain is often the first sign. Hip AVN may cause pain in the groin, buttock, hip, or thigh, particularly when walking or putting weight on the affected leg.
Yes. Hip pain is one of the most common symptoms of AVN of the hip. The pain may initially occur during activity or weight-bearing and may become more persistent as the condition progresses.
Yes. Avascular necrosis can affect both hips, particularly when it is associated with certain medical conditions, corticosteroid use, or other systemic risk factors.
AVN can result from an injury that damages the blood supply to the bone, long-term or high-dose corticosteroid use, excessive alcohol consumption, smoking, certain blood and autoimmune disorders, decompression sickness, and other conditions that interfere with blood circulation.
Excessive alcohol consumption is an established risk factor for AVN. Heavy alcohol use may interfere with normal bone and blood-vessel function and increase the risk of developing osteonecrosis.
Yes. Long-term or high-dose corticosteroid treatment can increase the risk of AVN. However, corticosteroids are important treatments for many medical conditions and should not be stopped suddenly or changed without medical advice.
Smoking can damage blood vessels and impair circulation. It may contribute to the development or progression of bone problems, and stopping smoking is generally beneficial for overall bone and vascular health.
The outlook depends on the cause, location, and stage of AVN. Early disease may sometimes be managed with measures intended to preserve the bone and delay progression. Once significant bone collapse has occurred, joint replacement may be necessary in some cases.
Diagnosis usually involves a medical history and physical examination followed by imaging. X-rays may show changes in more advanced disease, while MRI is particularly useful for detecting AVN at an early stage. CT scans or other tests may sometimes be used.
An X-ray can detect many changes associated with AVN, particularly in later stages. However, early AVN may not be visible on an X-ray, so an MRI may be recommended when AVN is suspected despite a normal or inconclusive X-ray.
There is no single treatment that is best for everyone. Treatment depends on the stage of AVN, the affected joint, the extent of bone damage, the person’s age and health, and the underlying cause. Options may include activity modification, pain management, physical therapy, procedures such as core decompression, and joint replacement in advanced cases.
Some early or less severe cases may be managed without surgery. Treatment may include reducing weight-bearing activities, using walking aids when recommended, managing pain, treating underlying medical conditions, and making appropriate lifestyle changes. However, non-surgical treatment may not prevent progression in every person.
Core decompression is a surgical procedure in which a channel or channels are created in the affected bone. It is primarily used in selected patients with early-stage AVN before substantial bone collapse and is intended to reduce pressure within the bone and support bone healing.
Hip replacement may be considered when AVN has caused significant collapse of the femoral head or advanced joint damage, particularly when pain and loss of function substantially affect daily activities.
Yes. When AVN causes collapse or irregularity of the joint surface, the joint can become progressively damaged and secondary osteoarthritis may develop.
Appropriate physical therapy and exercises may help maintain joint mobility and muscle strength. However, the type and amount of exercise should be guided by a healthcare professional because excessive weight-bearing or high-impact activity may be inappropriate when the bone is weakened.
19. Can avascular necrosis be prevented?
Not all cases can be prevented. However, reducing modifiable risk factors may help lower the risk. These measures include avoiding excessive alcohol consumption, stopping smoking, using corticosteroids only as prescribed, and properly managing medical conditions associated with AVN.
AVN can become serious if the affected bone progresses to structural collapse and joint damage. Early evaluation is important because treatment options may be more effective before significant bone collapse occurs.
See a healthcare professional if you have persistent or unexplained pain in the hip, knee, shoulder, or another joint, particularly if you have difficulty walking or bearing weight, a history of significant injury, long-term corticosteroid use, heavy alcohol exposure, or a medical condition associated with AVN.
An orthopedic surgeon commonly evaluates and treats AVN. A rheumatologist may also be involved when AVN is associated with autoimmune or inflammatory disease. Other specialists may be involved depending on the underlying cause.
Medical Disclaimer- This information is intended for general educational purposes and should not replace professional medical advice. If you have persistent joint pain or symptoms that may suggest avascular necrosis, consult a qualified healthcare professional for proper diagnosis and treatment.
