Understanding Avascular Necrosis: A Complete Patient Guide

Avascular necrosis is a condition in which part of a bone loses its blood supply, causing bone tissue to weaken and die. It most often affects the hip, but it can also involve the knee, shoulder, ankle, or other joints, and early diagnosis can help protect joint function.

Overview: what avascular necrosis means

Avascular necrosis is the death of bone tissue caused by an inadequate blood supply. It is also called osteonecrosis. Without enough blood flow, the affected part of the bone becomes weaker, may develop tiny fractures, and can eventually collapse. When this happens near a joint, the smooth joint surface may become uneven, leading to pain, stiffness, and arthritis-like damage.

This condition can affect different parts of the body, but it most often involves the head of the femur, the ball-shaped top of the thigh bone in the hip. It may also occur in the knee, shoulder, ankle, wrist, or jaw. In some people, only one bone is affected, while in others several joints can be involved.

Avascular necrosis does not always cause symptoms right away. In the early stages, a person may feel nothing at all, even though changes have begun inside the bone. Over time, however, pain usually develops, especially with weight-bearing or movement. Because the condition can progress silently at first, imaging tests are often important when a doctor suspects it.

A patient-friendly way to understand avascular necrosis is to think of bone as living tissue that needs constant circulation. If that circulation is interrupted for long enough, the bone cannot repair itself normally. Early recognition matters because some treatments are more effective before the bone surface collapses and joint damage becomes advanced.

Symptoms and how the condition may progress

The most common symptom of avascular necrosis is pain in the affected joint. In hip involvement, pain is often felt in the groin, buttock, or upper thigh. It may begin only with walking, climbing stairs, or standing for long periods. As the condition advances, pain can become more constant and may even be present at rest or during the night.

Stiffness and reduced range of motion may develop as the joint surface becomes less smooth. A person may notice limping, difficulty putting weight on one leg, trouble bending the joint, or discomfort when rotating the limb. If the knee or shoulder is affected, everyday activities such as reaching, kneeling, or getting up from a chair may become harder.

The course of the disease often depends on how much of the bone is affected and whether the bone has started to collapse. Small areas may remain stable for some time, while larger areas are more likely to progress. In later stages, secondary osteoarthritis can occur because the damaged bone no longer supports the joint properly.

• Early stage: no symptoms or mild pain with activity
• Middle stage: more frequent pain, stiffness, and reduced movement
• Later stage: persistent pain, limp, joint collapse, and arthritis-like changes

Causes and risk factors

Avascular necrosis can develop after an injury or without a clear injury. Trauma such as a hip fracture or dislocation can damage the blood vessels that feed the bone. This is one of the best-known causes. In other cases, blood flow may be reduced gradually because of changes inside the bone or blood vessels.

Several medical and lifestyle factors are associated with non-traumatic avascular necrosis. Long-term or high-dose corticosteroid use is an important risk factor, although the exact reason is not fully understood. Heavy alcohol use is also linked to the condition. Other associated conditions include sickle cell disease, autoimmune diseases, some clotting disorders, decompression sickness, and certain metabolic disorders. In some patients, no definite cause is found.

Avascular necrosis can occasionally appear after cancer treatment, organ transplantation, or radiation exposure to the affected area. Some people have increased risk because they already have a condition that affects circulation, blood clotting, or bone health. Doctors may also consider whether symptoms could relate to another joint problem, such as arthritis or a structural issue in the hip.

Having a risk factor does not mean a person will definitely develop avascular necrosis. Still, awareness is helpful. A patient with persistent joint pain and a history of steroid treatment, significant alcohol use, or major joint trauma should consider a medical assessment rather than waiting for symptoms to worsen.

How avascular necrosis is diagnosed

Diagnosis starts with a medical history and physical examination. A doctor will ask about pain location, when symptoms began, past injuries, medication use, alcohol intake, and medical conditions that may affect blood flow or bone strength. During the examination, they will look for tenderness, restricted movement, limping, and signs that one joint is functioning differently from the other.

Imaging tests are central to diagnosis. Plain X-rays may look normal in the earliest stages, but they can show later changes such as bone flattening or joint damage. Magnetic resonance imaging, often used when suspicion remains high despite a normal X-ray, is especially sensitive for early avascular necrosis and can show the extent of bone involvement. In some cases, computed tomography or bone scans may also help define the stage.

Doctors may order blood tests not to confirm avascular necrosis directly, but to look for possible contributing conditions such as inflammation, blood disorders, or metabolic problems. The main goals are to identify the cause when possible, assess how advanced the condition is, and understand how much of the joint is affected.

Because treatment choices often depend on disease stage, accurate imaging is very important. When needed, an orthopedic specialist may evaluate whether joint-preserving strategies are still possible or whether more advanced joint reconstruction should be discussed. This is also the stage when patients may learn about MRI scanning or other imaging methods used to guide care.

Treatment options and what they aim to achieve

Treatment for avascular necrosis depends on the size and location of the affected area, the stage of the condition, the patient’s age and activity level, and the underlying cause. The main aims are to reduce pain, slow or stop progression if possible, preserve the joint, and restore mobility. Early-stage disease is often approached differently from late-stage disease with collapse.

Non-surgical management may include limiting weight-bearing, using walking aids for a time, modifying activities, and starting physical therapy to maintain motion and muscle strength. Doctors may also address contributing factors, such as reviewing corticosteroid use when medically appropriate or advising reduction of alcohol intake. Pain-relieving medicines may be recommended, but medication alone does not reverse damaged bone.

When the disease is found early, procedures intended to preserve the joint may be considered. One example is core decompression, which removes a small channel of bone to reduce pressure and improve blood flow in the area. In selected cases, this may be combined with bone grafting or biological techniques. If there is advanced collapse or severe joint damage, joint replacement may offer the best chance of pain relief and improved function. For hip disease, this can mean hip replacement; in some situations, minimally invasive approaches or other orthopedic surgery may be discussed.

Rehabilitation is an important part of treatment whether surgery is needed or not. Exercise plans are usually tailored to the affected joint and stage of disease. Patients often do best when care is coordinated among orthopedic specialists, radiologists, rehabilitation teams, and physicians managing the underlying cause. In complex cases, related bone and joint conditions such as osteoporosis may also need attention.

Living with avascular necrosis: self-care and prevention

Self-care cannot cure avascular necrosis, but it can support treatment and reduce strain on the joint. Following the care plan closely is important, especially if a doctor has advised protected weight-bearing or temporary use of a cane or crutches. Continuing to overload a painful joint can worsen symptoms and may accelerate structural damage.

Low-impact movement is often helpful when approved by a clinician. Gentle strengthening, stretching, swimming, or stationary cycling may support mobility while placing less force on the joint than running or jumping. A physical therapist can help guide safe exercises and avoid movements that increase pain. Weight management may also help by reducing stress on the hips and knees.

Prevention is not always possible, especially after a sudden injury, but risk can sometimes be reduced. Using corticosteroids only as prescribed and for clear medical reasons, limiting alcohol intake, and seeking treatment for medical conditions that affect circulation or blood health may lower the chance of future problems. People with known risk factors should not ignore persistent joint pain simply because they can still walk.

For patients who need specialist assessment, Acibadem International’s multidisciplinary teams in JCI-accredited hospitals evaluate and treat avascular necrosis for international patients, including advanced imaging, rehabilitation, and joint-preserving or reconstructive procedures when appropriate.

When to seek medical care

Medical advice is recommended if joint pain lasts more than a few weeks, keeps returning, or starts to interfere with walking, climbing stairs, sleep, or daily activities. This is especially important for pain in the groin, hip, knee, or shoulder that has no obvious short-term explanation. Early assessment may identify avascular necrosis before major joint collapse occurs.

A person should also seek care sooner if they have joint pain plus important risk factors such as a recent fracture or dislocation, long-term corticosteroid use, heavy alcohol use, sickle cell disease, or another condition that affects blood supply. In these settings, waiting for symptoms to become severe can delay diagnosis.

Urgent evaluation is sensible if pain follows major trauma, if a joint suddenly becomes very difficult to move, or if a person cannot bear weight. These situations may have causes other than avascular necrosis, but they still need prompt medical attention. A qualified doctor can determine whether imaging, specialist referral, or immediate treatment is needed.

Frequently asked questions

Is avascular necrosis the same as osteonecrosis?

Yes. Avascular necrosis and osteonecrosis are different names for the same condition, which happens when part of a bone loses its blood supply. Some clinicians also use the term bone infarction in certain contexts.

Can avascular necrosis heal on its own?

Spontaneous recovery is uncommon, especially once symptoms are established or the bone has started to weaken. Small early lesions may remain stable for a time, but many cases progress without appropriate monitoring or treatment.

Which joint is most often affected by avascular necrosis?

The hip is the most commonly affected joint, particularly the femoral head. However, avascular necrosis can also involve the knee, shoulder, ankle, wrist, or other bones.

Does avascular necrosis always require surgery?

No. Early-stage avascular necrosis may sometimes be managed with activity changes, reduced weight-bearing, physical therapy, and careful follow-up. Surgery becomes more likely when symptoms are significant, the affected area is large, or the bone has already collapsed.

How is avascular necrosis found early if an X-ray is normal?

MRI is often the most useful test for early detection because it can show changes in the bone before they appear on standard X-rays. Doctors usually order it when symptoms and risk factors raise concern despite inconclusive initial imaging.

What happens if avascular necrosis is left untreated?

If the condition progresses, the weakened bone may collapse and damage the joint surface. This can lead to chronic pain, stiffness, reduced mobility, and eventually osteoarthritis-like joint degeneration.

References

• National Institute of Arthritis and Musculoskeletal and Skin Diseases
• American Academy of Orthopaedic Surgeons
• Mayo Clinic
• National Organization for Rare Disorders
• MedlinePlus

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.