What is avascular necrosis. How does it affect bones and joints. What are the main causes and risk factors for developing avascular necrosis. How is avascular necrosis diagnosed and treated. What are the long-term implications of this condition.

Understanding Avascular Necrosis: A Comprehensive Overview

Avascular necrosis, also known as osteonecrosis, is a serious condition that occurs when the blood supply to a bone is disrupted, leading to tissue death and potential bone collapse. This condition can affect any bone in the body but most commonly impacts the ends of long bones, particularly those near major joints.

The consequences of avascular necrosis can be severe, especially when it develops near a joint. As the bone tissue dies and collapses, it can cause the joint surface to deteriorate, leading to pain, limited mobility, and potentially requiring joint replacement surgery if left untreated.

The Scope of Avascular Necrosis

Avascular necrosis can manifest in various ways:

• It may affect a single bone
• Multiple bones can be impacted simultaneously
• Different bones may be affected at different times

The unpredictable nature of this condition makes it crucial for individuals at risk to be vigilant and seek medical attention if they experience persistent joint pain or reduced range of motion.

Causes and Risk Factors of Avascular Necrosis

Understanding the underlying causes and risk factors of avascular necrosis is essential for both prevention and early intervention. While the exact cause may not always be identifiable, several factors have been associated with an increased risk of developing this condition.

Primary Causes of Avascular Necrosis

The most common causes of avascular necrosis include:

1. Traumatic injuries, such as bone fractures or dislocations
2. Damage to blood vessels supplying the bone
3. Long-term use of corticosteroid medications
4. Excessive alcohol consumption over an extended period
5. Certain chronic health conditions

Are certain medical conditions linked to a higher risk of avascular necrosis? Indeed, several health issues have been associated with an increased likelihood of developing this condition:

• Sickle cell anemia
• Pancreatitis
• HIV
• Autoimmune diseases
• Blood clotting disorders

Additional Risk Factors

Beyond the primary causes, several other factors can contribute to the development of avascular necrosis:

• Radiation therapy
• Chemotherapy treatments
• Decompression sickness (also known as “the bends”)
• High cholesterol levels
• Previous bone surgeries

Understanding these risk factors is crucial for individuals who may be at higher risk of developing avascular necrosis. By recognizing the potential causes, patients and healthcare providers can work together to implement preventive measures and monitor for early signs of the condition.

Recognizing the Symptoms of Avascular Necrosis

Identifying the symptoms of avascular necrosis early can be challenging, as the condition often progresses gradually. However, being aware of the potential signs can lead to earlier diagnosis and more effective treatment.

Common Symptoms

The most frequently reported symptoms of avascular necrosis include:

• Mild joint pain in the early stages
• Progressive worsening of joint pain as the condition advances
• Limited range of motion due to pain and joint damage

Can the symptoms of avascular necrosis be mistaken for other conditions? Yes, the symptoms of avascular necrosis can often mimic other bone and joint disorders, making accurate diagnosis crucial. Patients experiencing persistent joint pain or reduced mobility should consult a healthcare provider for a thorough evaluation.

Progression of Symptoms

The progression of avascular necrosis symptoms typically follows a pattern:

1. Initial mild discomfort or pain in the affected joint
2. Gradual increase in pain intensity, especially during weight-bearing activities
3. Pain may become constant, even at rest
4. Reduced range of motion and stiffness in the affected joint
5. Potential joint collapse in advanced stages, leading to severe pain and disability

Understanding this progression can help patients and healthcare providers identify the condition at an earlier stage, potentially improving treatment outcomes.

Diagnostic Approaches for Avascular Necrosis

Accurate diagnosis of avascular necrosis is crucial for developing an effective treatment plan. Healthcare providers employ a combination of clinical evaluation and advanced imaging techniques to confirm the presence of the condition and assess its severity.

Clinical Evaluation

The diagnostic process typically begins with:

• A comprehensive medical history review
• Physical examination of the affected area
• Assessment of risk factors and potential causes

Imaging Techniques

Various imaging modalities play a crucial role in diagnosing avascular necrosis:

1. X-rays: These provide initial images of bone structure and can reveal changes in bone density or shape.
2. CT (Computed Tomography) scans: Offer more detailed images of bone structures and can detect early stages of bone damage.
3. MRI (Magnetic Resonance Imaging): Considered the gold standard for diagnosing avascular necrosis, as it can detect early changes in bone marrow and soft tissues.
4. Radionuclide bone scans: Use a small amount of radioactive material to highlight areas of increased bone activity, which can indicate avascular necrosis.

How does MRI contribute to the early detection of avascular necrosis? MRI is particularly valuable in diagnosing avascular necrosis because it can detect changes in bone marrow and soft tissues before structural changes become apparent on X-rays or CT scans. This allows for earlier intervention and potentially better treatment outcomes.

Additional Diagnostic Procedures

In some cases, healthcare providers may recommend additional procedures to confirm the diagnosis or assess the extent of bone damage:

• Bone biopsy: Involves removing a small sample of bone tissue for microscopic examination.
• Functional bone assessment: Typically performed during surgery to measure pressure within the bone, which can indicate compromised blood flow.

These comprehensive diagnostic approaches enable healthcare providers to accurately identify avascular necrosis and develop tailored treatment plans based on the condition’s stage and severity.

Treatment Strategies for Avascular Necrosis

The treatment of avascular necrosis aims to prevent further bone deterioration, relieve pain, and improve joint function. The approach to treatment varies depending on the stage of the condition, the affected bone, and the patient’s overall health status.

Conservative Treatment Options

For early-stage avascular necrosis or cases where surgery is not immediately necessary, conservative treatments may be recommended:

• Medications: Pain relievers and anti-inflammatory drugs to manage symptoms
• Physical therapy: To maintain joint mobility and strengthen surrounding muscles
• Assistive devices: Crutches or canes to reduce weight-bearing on the affected joint
• Lifestyle modifications: Limiting alcohol consumption and avoiding high-impact activities

Can lifestyle changes alone halt the progression of avascular necrosis? While lifestyle modifications are important in managing the condition, they are typically most effective when combined with other treatments and when implemented in the early stages of the disease.

Surgical Interventions

As avascular necrosis progresses, surgical options may become necessary:

1. Core decompression: A procedure to reduce pressure within the bone and improve blood flow
2. Bone grafting: Replaces damaged bone with healthy bone to support the joint
3. Osteotomy: Involves reshaping the bone to reduce stress on the affected area
4. Joint replacement: In advanced cases, replacing the damaged joint with an artificial one may be necessary

The choice of surgical intervention depends on factors such as the patient’s age, the stage of the disease, and the specific bone or joint affected.

Emerging Therapies

Research into new treatment approaches for avascular necrosis is ongoing. Some promising areas include:

• Stem cell therapy: Using the patient’s own stem cells to promote bone healing
• Growth factor treatments: Applying proteins that stimulate bone and blood vessel growth
• Hyperbaric oxygen therapy: Exposing patients to high-pressure oxygen to enhance tissue repair

While these therapies show promise, many are still in the experimental stage and require further research to establish their long-term effectiveness and safety.

Long-Term Outlook and Management of Avascular Necrosis

The prognosis for individuals with avascular necrosis can vary significantly depending on several factors, including the stage at diagnosis, the bones affected, and the underlying cause. Understanding the long-term implications of this condition is crucial for patients and healthcare providers alike.

Factors Influencing Prognosis

Several key factors can impact the long-term outlook for patients with avascular necrosis:

• Early diagnosis and intervention
• The extent of bone damage at the time of diagnosis
• The underlying cause of the condition
• The patient’s overall health and ability to adhere to treatment plans
• The specific bone or joint affected

How does early intervention affect the prognosis of avascular necrosis? Early diagnosis and treatment can significantly improve outcomes by preventing or slowing bone deterioration, potentially avoiding the need for more invasive interventions like joint replacement surgery.

Ongoing Management Strategies

Managing avascular necrosis is often a long-term process that requires a multifaceted approach:

1. Regular medical follow-ups to monitor disease progression
2. Adherence to prescribed treatments and medications
3. Lifestyle modifications to reduce stress on affected bones and joints
4. Physical therapy and exercise programs to maintain joint function and muscle strength
5. Pain management techniques, including both pharmacological and non-pharmacological approaches

Patients with avascular necrosis may need to work closely with a team of healthcare providers, including orthopedic specialists, rheumatologists, and physical therapists, to manage their condition effectively over time.

Quality of Life Considerations

Living with avascular necrosis can have significant impacts on a person’s quality of life. Patients may experience:

• Chronic pain and discomfort
• Limited mobility and reduced ability to perform daily activities
• Emotional and psychological challenges related to chronic pain and disability
• Potential need for long-term pain management strategies
• Possible career limitations or changes due to physical limitations

Support groups and counseling services can be valuable resources for individuals coping with the long-term effects of avascular necrosis, providing both emotional support and practical advice for managing the condition.

Prevention and Risk Reduction for Avascular Necrosis

While not all cases of avascular necrosis can be prevented, there are steps individuals can take to reduce their risk or prevent the condition from worsening if they are at high risk.

Lifestyle Modifications

Adopting healthy lifestyle habits can play a significant role in reducing the risk of avascular necrosis:

• Limiting alcohol consumption
• Avoiding or quitting smoking
• Maintaining a healthy weight to reduce stress on joints
• Engaging in low-impact exercises to promote bone health
• Managing underlying health conditions effectively

Can dietary changes help prevent avascular necrosis? While no specific diet has been proven to prevent avascular necrosis, a balanced diet rich in calcium and vitamin D can support overall bone health. Additionally, maintaining a healthy weight through proper nutrition can reduce stress on joints, potentially lowering the risk of developing the condition.

Medical Management for High-Risk Individuals

For individuals at higher risk of developing avascular necrosis, proactive medical management is crucial:

1. Regular medical check-ups to monitor bone health
2. Careful management of conditions that increase risk, such as sickle cell anemia or lupus
3. Judicious use of corticosteroids, with close monitoring by healthcare providers
4. Early intervention for injuries that could lead to avascular necrosis
5. Consideration of preventive treatments for those at very high risk

Healthcare providers may recommend additional preventive measures for patients with specific risk factors, such as those undergoing treatments known to increase the risk of avascular necrosis.

Education and Awareness

Raising awareness about avascular necrosis and its risk factors is essential for prevention and early detection. Key areas of focus include:

• Educating patients about the potential side effects of long-term corticosteroid use
• Promoting awareness of the link between excessive alcohol consumption and bone health
• Encouraging prompt medical attention for persistent joint pain or reduced mobility
• Providing information about the importance of bone health in overall wellness

By combining lifestyle modifications, proactive medical management, and increased awareness, individuals can take significant steps towards reducing their risk of developing avascular necrosis or managing the condition effectively if it does occur.

Avascular Necrosis | Cedars-Sinai

ABOUT

CAUSES
DIAGNOSIS

TREATMENT

NEXT STEPS

What is avascular
necrosis?

Avascular necrosis is a disease that results from the short-term (temporary) or
lifelong (permanent) loss of blood supply to the bone. When blood supply is cut off,
the
bone tissue dies and the bone collapses. If avascular necrosis happens near a joint,
the
joint surface may collapse.

This condition may happen in any bone. It most commonly happens in the ends of a long
bone. It may affect one bone, several bones at one time, or different bones at different
times.

What causes avascular necrosis?

Avascular necrosis may be the result of:

• Injury
• Broken
  bone (fracture)
• Harm to
  blood vessels
• Long-term use of medicines, such as corticosteroids
• Heavy,
  long-term use of alcohol
• Certain
  long-term (chronic) health conditions

Who is at risk for avascular
necrosis?

You
are more at risk if any of these apply to you:

• Injury
• Bone surgery
• Steroid
  use
• Alcohol
  use
• Blood
  disorders, such as sickle cell anemia
• Radiation treatments
• Chemotherapy
• Pancreatitis
• Diver’s
  disease or “the bends” (decompression sickness)
• Blood
  clots easily
• High
  cholesterol
• Autoimmune disease
• HIV

What are the symptoms of avascular necrosis?

The
following are the most common symptoms of avascular necrosis. But symptoms occur a
bit
differently in each person. Symptoms may include:

• Minor
  early joint pain
• Joint
  pain gets worse as bone and joint start to collapse
• Limited
  range of motion because of pain

The
symptoms of avascular necrosis may look like other health conditions or bone problems.
Always talk with your healthcare provider for a diagnosis.

How is avascular necrosis diagnosed?

Along with a complete medical history and physical exam, you may have one or more
of the following tests:

• X-ray. This test uses energy beams to make images of internal tissues, bones,
  and organs onto film.
• CT
  scan.
  This is an imaging test that uses X-rays and a computer to make
  detailed images of the body. A CT scan shows details of the bones, muscles, fat, and
  organs. CT scans are more detailed than general X-rays.
• MRI. This test uses large magnets, radio waves, and a computer to make detailed
  images of organs and structures in the body.
• Radionuclide
  bone scan.
   This imaging test uses a very small amount of radioactive
  material. It is injected into the blood to be seen by a scanner. This test shows
  blood flow to the bone and cell activity in the bone.
• Biopsy.

  The healthcare provider removes tissue samples with a needle or during surgery.
  The samples are looked at under a microscope. It’s done to find cancer or other
  abnormal cells or to remove tissue from the affected bone.

• Functional
  assessment of bone.
  These tests often are done during surgery to measure the
  pressure inside the bone.

How is avascular necrosis treated?

Treatment will depend on your symptoms, age, and general health. It
will also depend on how severe the condition is.

The
goal of treatment is to improve your ability to use the joint and stop more damage
to
the bone or joint. Treatments are needed to keep joints from breaking down. They may
include:

• Medicines.

  These are used to control pain.

• Assistive
  devices.
  These are used to reduce weight on the bone or joint.
• Core
  decompression.
  For this surgery, the inner layer of bone is removed to reduce
  pressure, increase blood flow, and slow or stop bone and joint destruction.
• Osteotomy.

  This procedure reshapes the bone and reduces stress on the affected area.

• Bone graft.

  In this procedure, healthy bone is transplanted from another part of the body
  into the affected area.

• Joint
  replacement.
  This surgery removes and replaces an arthritic or damaged joint
  with an artificial joint. This may be considered only after other treatments have
  failed to ease pain or disability.

Other
treatments may include certain medicines and combination therapies to promote bone
growth.

Key points about avascular necrosis

• Avascular necrosis is a disease that results from the temporary or permanent loss
  of blood supply to the bone. It happens most commonly in the ends of a long bone.
• Avascular necrosis may be the result of injury, use of medicines, or alcohol. Or it
  may occur after bone injury or bone surgery.  
• Symptoms may include joint pain and limited range of motion.
• Medicines, assistive devices, or surgery may be used to improve functionality or to
  stop more damage to the affected bone or joint.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your provider tells
  you.
• At the visit, write down the name of a new diagnosis, and any new medicines, treatments,
  or tests. Also write down any new instructions your provider gives you.
• Know why a new medicine or treatment is prescribed, and how it will help you. Also
  know what the side effects are.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if you do not take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that
  visit.
• Know how
  you can contact your provider if you have questions.

Medical Reviewer: Thomas N Joseph MD

Medical Reviewer: Raymond Turley Jr PA-C

Medical Reviewer: L Renee Watson MSN RN

© 2000-2022 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional’s instructions.

Osteonecrosis of the Hip – OrthoInfo

Osteonecrosis of the hip is a painful condition that occurs when the blood supply to the head of the femur (thighbone) is disrupted. Because bone cells need a steady supply of blood to stay healthy, osteonecrosis can ultimately lead to destruction of the hip joint and severe arthritis.

Osteonecrosis is also called avascular necrosis (AVN) or aseptic necrosis. Although it can occur in any bone, osteonecrosis most commonly affects the hip. More than 20,000 people each year enter hospitals for treatment of osteonecrosis of the hip. In many cases, both hips are affected by the disease. 

The hip is a ball-and-socket joint. The socket is formed by the acetabulum, which is part of the large pelvis bone. The ball is the femoral head, which is the upper end of the femur (thighbone).

The surface of the ball and socket is covered with articular cartilage, a smooth, slippery substance that protects the bones and enables them to glide easily across each other. 

Osteonecrosis of the hip occurs in the femoral head, which is the ball of ball-and-socket hip joint.

Osteonecrosis of the hip develops when the blood supply to the femoral head is disrupted. Without adequate nourishment, the bone in the head of the femur dies and gradually collapses. As a result, the articular cartilage covering the hip bones also collapses, leading to disabling arthritis.

Osteonecrosis can affect anyone, but is more common in people between the ages of 40 and 65. Men develop osteonecrosis of the hip more often than women.

In osteonecrosis, the bone in the head of the femur slowly dies.

Risk Factors

It is not always known what causes the lack of blood supply, but doctors have identified a number of risk factors that can make someone more likely to develop osteonecrosis:

• Injury. Hip dislocations, hip fractures, and other injuries to the hip can damage the blood vessels and impair circulation to the femoral head.
• Excessive alcohol use. Overconsumption of alcohol over time can cause fatty deposits to form in the blood vessels and can elevate cortisone levels, resulting in a decreased blood supply to the bone.
• Corticosteroid medicines. Many diseases, including asthma, rheumatoid arthritis, and systemic lupus erythematosus, are treated with steroid medications. Although it is not known exactly why these medications can lead to osteonecrosis, research shows that there is a connection between the disease and long-term corticosteroid use.
• Medical conditions. Osteonecrosis is associated with other diseases, including Caisson disease (diver’s disease, or “the bends”), sickle cell disease, myeloproliferative disorders, Gaucher’s disease, systemic lupus erythematosus, Crohn’s disease, arterial embolism, thrombosis, and vasculitis. 

Osteonecrosis develops in stages. Hip pain is typically the first symptom. This may lead to a dull ache or throbbing pain in the groin or buttock area. As the disease progresses, it becomes more difficult to stand and put weight on the affected hip, and moving the hip joint is painful.

It may take from several months to over a year for the disease to progress. It is important to diagnose osteonecrosis early, because some studies show that early treatment is associated with better outcomes.  

The four stages of osteonecrosis. The disease can progress from a normal, healthy hip (Stage I) to the collapse of the femoral head and severe osteoarthritis (Stage IV).  

Reproduced and adapted from Beaule PE, Amstutz, HC: Management of ficat stage III and IV osteonecrosis of the hip. J Amer Acad Orthop Surg 2004; 12: 96-105.

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After discussing your symptoms and medical history, your doctor will examine your hip to discover which specific motions cause your pain.

Patients with osteonecrosis often have severe pain in the hip joint but relatively good range of motion. This is because only the femoral head is involved in the earlier stages of the disease. Later, as the surface of the femoral head collapses, the entire joint becomes arthritic. Loss of motion and stiffness can then develop.

During the exam, the doctor will move your hip in different ways to learn more about your pain. 

Reproduced from JF Sarwark, ed: Essentials of Musculoskeletal Care, ed 4. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2010.

Imaging Tests

Imaging studies will help your doctor confirm the diagnosis.

X-rays. X-rays provide images of dense structures, such as bone. X-rays are used to determine whether the bone in the femoral head has collapsed and to what degree. 

(Left) An X-ray of a healthy hip joint. (Right)  In this X-ray, the osteonecrosis has progressed to collapse of the femoral head.

Osteonecrosis is typically seen as a wedge-shaped area with a dense whitish sclerotic (hardened) border in the superior lateral portion of the femoral head. On the lateral view, a line called a “crescent sign” can often be seen just below the surface of the femoral head. 

(Left) This X-ray shows osteonecrosis of the hip. (Right) When viewed close up, the X-ray reveals the “crescent sign” that is typically seen before collapse of the femoral head.  

Magnetic resonance imaging (MRI) scans. Early changes in the bone that may not show up on an x-ray can be detected with an MRI scan. These scans are used to evaluate how much of the bone is affected by the disease. An MRI may also show early osteonecrosis that has yet to cause symptoms (for example — osteonecrosis that may be developing in the opposite hip joint). 

This MRI scan shows osteonecrosis in a patient’s right hip (white arrow). The dark line (red arrows) denotes the border between dead bone and living bone. The patient’s left hip is normal.

Although nonsurgical treatment options — such as anti-inflammatory medications, activity changes, and using crutches  — can help relieve pain and slow the progression of the disease, the most successful treatment options are surgical. Patients with osteonecrosis that is caught in the very early stages (before the femoral head collapses) are potential candidates for hip-preserving procedures.

There are several different surgical procedures used to treat osteonecrosis of the hip.

Core Decompression and Grafting

This procedure involves drilling one large hole or several smaller holes into the femoral head to relieve pressure in the bone and create channels for new blood vessels to nourish the affected areas of the hip.

When osteonecrosis of the hip is diagnosed early, core decompression is sometimes successful in preventing collapse of the femoral head and the development of arthritis. 

(Left) Illustration of core decompression. (Right) In this X-ray, the drill lines show the pathway of the small drill holes used in the procedure. 

Core decompression is often combined with bone and cartilage grafting to help regenerate healthy bone and support cartilage at the hip joint. A bone graft is healthy bone tissue that is transplanted to an area of the body where it is needed. The tissue may be taken from a donor (allograft) or from another bone in your body (autograft).

There are also several synthetic bone grafts available today. Sometimes, your own bone marrow cells may be mixed together with the graft substitute to help in the bone regeneration process. It is importat to speak with your surgeon about the available options that may be used for your procedure.

Vascularized Fibula Graft

Another surgical option is a vascularized fibula graft. In this procedure, a segment of bone is taken from the small bone in your leg (fibula) along with its blood supply (an artery and vein). This graft is transplanted into a hole created in the femoral neck and head, and the artery and vein are reattached to help heal the area of osteonecrosis. 

Two different X-ray views showing osteonecrosis of the hip.

Two X-ray views of the hip after treatment with a vascularized fibular graft.

Total Hip Replacement

In total hip replacement, both the head of the femur and the socket are replaced with an artificial device.

If osteonecrosis has advanced to the point where the femoral head has already collapsed, the most successful treatment is total hip replacement. In this procedure, your doctor removes the damaged bone and cartilage, then positions new metal or plastic joint surfaces to restore the function of your hip.  

Core decompression prevents osteonecrosis from progressing to severe arthritis and the need for hip replacement in some cases. This depends upon the stage and size of the osteonecrosis at the time of the procedure.

Core decompression achieves the best results when osteonecrosis is diagnosed in its early stages, before the bone collapses. In some of these cases, the bone heals and regains its blood supply after core decompression. It takes a few months for the bone to heal and, during this time, you will need to use a walker or crutches to avoid putting stress on the damaged bone.

Patients with successful core decompression procedures typically return to walking unassisted in about 3 months and may have complete pain relief.

Vascularized fibular grafting is an invasive procedure that requires several months of healing. Typically, you are non-weightbearing for the first several weeks; you will then gradually start weightbearing with an ambulatory assistive device (walker or cane). If a vascularized fibular graft is performed prior to femoral head collapse, the clinical outcomes are usually favorable.

When osteonecrosis is diagnosed after collapse of the bone, core decompression is not usually successful in preventing further collapse. In this situation, the patient is best treated with a total hip replacement. Total hip replacement is successful in relieving pain and restoring function in the majority of patients with osteonecrosis. 

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Avascular Necrosis (AVN)/Osteonecrosis – together by St. Jude

Other names: OH, aseptic necrosis, ischemic bone necrosis

What is avascular necrosis (AVN)?

Avascular necrosis (osteonecrosis) is a condition in which part of the bone dies due to poor blood supply. Avascular necrosis may be a side effect of certain cancers or treatments.

Children at high risk are those receiving high doses of corticosteroids (dexamethasone and prednisone).

Avascular necrosis may be mild and improve after treatment is completed, or it may be severe, accompanied by severe pain and long-term disability.

Avascular necrosis in children with cancer

Avascular necrosis (AVN) is a common side effect of treatment for leukemia and lymphoma. Nearly half of children treated for acute lymphoblastic leukemia (ALL) suffer from some degree of avascular necrosis. In addition, the high-risk group includes children who have undergone bone marrow transplantation.

In children with cancer, avascular necrosis often occurs at the ends of long bones, at a site called the epiphysis.

This disease can affect any bone. However, in children with cancer, avascular necrosis often occurs at the ends of long bones, at a site called the epiphysis.

Avascular necrosis can be accompanied by pain and affect joint function, especially knee, hip, shoulder and ankle. Damage to the bone and joint can lead to long-term problems such as joint destruction and arthritis.

In cancer treatment, avascular necrosis is more common in older children and adolescents than in young children or adults. In children younger than 10 years, this condition is less common.

Avascular necrosis can be difficult to diagnose in its early stages. The patient may not experience pain or other symptoms until severe bone damage develops. The condition of high-risk children should be monitored throughout the course of treatment.

Treatment of avascular necrosis depends on the severity of the pain and the degree of bone destruction. Pain relief and physical therapy can help manage symptoms. Some patients may require surgery to improve blood flow and relieve pressure within the bone. In case of severe damage or destruction of the joint, the patient may eventually need arthroplasty.

Symptoms of avascular necrosis

Some patients may not show symptoms at all, especially in the early stages. As the condition worsens, pain in the joint or bone may appear. Family members may notice that the child has begun to limp, tries not to use the affected joint, stiffness or limitation of range of motion may become noticeable. Occasionally, avascular necrosis can lead to bone destruction, with the pain escalating dramatically.

Avascular necrosis can develop in one place or in several bones at once (multifocal course). Chemotherapy affects the entire body, so when treating childhood cancer, avascular necrosis usually occurs in several joints, most commonly in the knee and/or hip. Other joints, such as the shoulder and ankle, may also be affected.

In general, the presence of pain and disability depends on the following factors:

• Which parts of the bone are affected
• How severe is the avascular necrosis
• How quickly progresses
• To what extent the bone is able to regenerate

However, pain cannot be considered a reliable indicator of the severity of avascular necrosis. Avascular necrosis in a small area can be very painful. At the same time, other patients may not have pain at all, despite the very large area affected by avascular necrosis.

Symptoms of avascular necrosis

• Pain (may be temporary or permanent)
• Joint stiffness or “stuck”
• Lameness or change in gait
• Tendency not to use the affected joint or avoidance of certain activities
• Problems getting up or down stairs

Factors that increase the risk of developing avascular necrosis

• High doses of dexamethasone or prednisone as part of cancer treatment
• Age over 10 years
• Sickle cell disease
• High-dose bone irradiation
• Treatment with asparaginase and dexamethasone
• Congenital genetic changes

Causes of avascular necrosis

Avascular necrosis is a complex process. The main reason for the development of avascular necrosis is a decrease in blood flow to the bone. If the blood vessels are too thin, damaged, or clogged, nutrients and oxygen cannot reach the bone, causing bone cells to begin to die.

Cancer treatments, including chemotherapy and radiation, can cause bone cell death and/or affect bone repair. As a result, the bone can break down faster than it has time to recover from damage. In addition, the treatment may affect the blood supply to the bones, leading to avascular necrosis.

Many children receive corticosteroid drugs (eg, dexamethasone, prednisone) for chemotherapy. These drugs are also used to combat side effects such as nausea and swelling. However, corticosteroids can increase the level of fatty substances (lipids) in the blood. Accumulation of fats in blood vessels can lead to blockage. In addition, these drugs can cause changes in the cells that line the walls of blood vessels, thereby thinning and weakening blood vessels.

Chronic high-dose dexamethasone is associated with a higher risk of developing avascular necrosis than prednisone or intermittent dexamethasone. Some drugs, such as asparaginase, can also interfere with the action of dexamethasone and increase the risk of developing avascular necrosis because these drugs interact with each other. Other drugs (eg, methotrexate) can also cause bone damage and increase the risk of avascular necrosis, especially when used with corticosteroids.

Diagnosis of avascular necrosis

Different medical centers have different approaches to identifying patients at risk and monitoring their condition. Imaging methods are used to identify areas of avascular necrosis (sometimes called foci). Magnetic resonance imaging (MRI) is the most sensitive diagnostic imaging modality for diagnosing avascular necrosis. X-rays are less sensitive, but may be useful for monitoring progression and for monitoring the patient’s condition in the postoperative period. Less commonly, other methods such as bone scintigraphy and computed tomography (CT) are used.

Some clinics screen children at high risk to detect avascular necrosis even if they are asymptomatic. As a rule, such screening is part of a clinical or scientific research program and is mainly carried out for the knee and hip joints. When screening high-risk patients who are asymptomatic, the most common finding of avascular necrosis is on diagnostic imaging of the knee. As a rule, necrosis is observed on both sides of the knee joint (femoral and tibial), the knee may be the only affected joint. However, if avascular necrosis is found in the hip joint, the knees are also most commonly affected.

Avascular necrosis associated with high doses of corticosteroids usually becomes visible on MRI within the first year of therapy. If a patient does not show signs of avascular necrosis on MRI after 12 months of therapy, then even continued use of corticosteroids will most likely not cause the development of this condition.

Physicians are constantly looking for more accurate diagnostic methods through the use of more sensitive imaging techniques. In addition, research is underway in the field of predicting the development of avascular necrosis.

Progression of avascular necrosis

The course of avascular necrosis is difficult to predict. Lesions may grow, remain stable, or disappear. Progression can be fast or slow.

The severity (or stage) of avascular necrosis is important to know for treatment planning. Doctors consider two main factors:

1. Size of lesions
2. Is the bone on which the articular surface rests damaged

If the damaged bone cannot support the joint surface, the bone tissue under the cartilage will begin to break down. The normally smooth layer of cartilage that lines the joints begins to flake off. This leads to problems in the joint, including arthritis, pain and decreased mobility of the joint.

Joint destruction is more likely if the lesion is:

• close to the surface of the joint
• large, occupies 30% or more of the entire surface
• located in a weight-bearing joint (thigh, knee)

Since the knee and hip joints work under weight load, in severe cases of avascular necrosis, their destruction is quite common. If the focus of avascular necrosis in the hip joint occupies more than 30% of the joint surface, joint destruction usually occurs within 2 years.

Treatment of avascular necrosis

Treatment of avascular necrosis is always individual. Doctors take into account the following factors:

• Patient age
• Patient health and cancer stage
• Cancer treatment used and chemotherapy schedule
• Stage of avascular necrosis
• What bones and joints are affected
• Severity of pain

The main treatment is to relieve pain, keep the joint functioning and prevent further damage.

Treatment strategies may include the following:

Medications

Your doctor may prescribe pain medications, including NSAIDs (meloxicam, celecoxib) or acetaminophen. However, some painkillers put the patient at risk for bleeding, kidney or liver problems, or worsening the side effects of chemotherapy. Family members should check with their doctor before giving a child any medications, even over-the-counter medications, as they may interact with other medications or increase side effects.

Research is underway to prevent or treat avascular necrosis with drugs that affect blood flow, blood clotting, inflammation, fat metabolism, and/or bone cells. However, it has not yet been possible to achieve sustainable positive results.

Physiotherapy

Physiotherapy is an important part of the treatment of avascular necrosis. The physiotherapist will recommend how to reduce the weight load or eliminate painful activities. They may also prescribe special treatments, including:

• Exercises to help with the patient’s limitations (muscle weakness, joint stiffness, or trouble walking).
• Aids (walkers, crutches or canes) to aid mobility and reduce weight bearing on the affected joint. The physiotherapist will select the appropriate option and teach the patient how to walk with their help.
• Orthoses and support bandages (foot, knee or arm) support the affected joint and help reduce pain during daily tasks
• Instructions for home care, including gymnastics, recommendations for exercise and treatment with heat and/or cold

Avascular necrosis and weight-bearing effects

Reduced weight-bearing is recommended to avoid joint damage, severe pain and healing after surgery. However, many doctors and physiotherapists recommend that the patient perform light activities, as far as pain allows. Physical activity is important for increasing blood circulation, improving bone healing, and strengthening muscles, which reduces stress on the joints.

Patients with avascular necrosis should avoid high impact activities such as running, jumping and contact sports. This is especially important in patients with severe avascular necrosis to avoid joint destruction due to trauma.

Complementary or integrative therapies

The patient may benefit from psychosomatic therapies (eg, massage, acupuncture, biofeedback, and relaxation techniques). Special techniques help to cope with pain, reduce stress, reduce muscle tension and improve blood flow. Before using any new treatments, the patient’s family should consult with their physician to ensure they are safe and appropriate for the patient.

Adjustment of chemotherapy

In the case of severe avascular necrosis, the treatment team may recommend changing the chemotherapy plan to reduce the body’s exposure to corticosteroids. Such decisions should be made taking into account the risks to the health of patients in general.

Surgery

Some patients require surgery to treat avascular necrosis. The operation will speed up the healing of the bone and prevent its further damage. Joint replacement may also be required. The following types of procedures are possible:

• Bone decompression – This procedure is performed to reduce pressure within the bone, increase blood flow and thereby improve healing speed. With this decompression, the surgeon drills small holes in the bone, cracking open the damaged tissue. After the dead tissue is removed, the voids can be filled with a bone graft. This is a minimally invasive surgery requiring only a small incision. It usually takes several weeks of rest or weight-bearing to heal. Typically, patients recover quickly and report less pain and improved joint function.
• Bone graft is a surgical procedure performed for avascular necrosis to replace and restore bone tissue with a bone graft. In this case, the transplanted tissue can be taken from the patient himself (from another bone, autograft) or from a donor (allograft). In addition, artificial materials can be used. If the cartilage is damaged, a combined bone and cartilage graft may be used. In some cases, blood vessels are also transplanted along with the bone tissue. This material is called a vascularized bone graft. It can help improve the blood supply to the joint. In avascular necrosis, bone grafting is most often used in conjunction with bone decompression.
• Arthroscopy is a type of minimally invasive procedure in which a miniature camera and fine surgical instruments are inserted through small incisions. In patients with avascular necrosis, arthroscopy may be used to repair torn cartilage, smooth the surface of a bone, or remove debris from inside a joint. This can relieve symptoms such as pain, stiffness, and a “stuck” joint.
• Osteotomy – This surgical operation is used to reduce the weight load on the affected area by reshaping or repositioning the bone. During this procedure, a wedge-shaped incision is made in the bone, after which the bone can be rotated, thereby changing the load on it. In the new position, the bone is held by plates, staples or screws until it heals. Osteotomy can help prevent joint destruction, delaying or eliminating the need for a joint replacement.
• Arthroplasty (Arthroplasty) – Joint replacement surgery may be required for severe bone disease. During this operation, the affected bone is removed and replaced with an artificial joint. Endoprosthetics may be needed for young patients after joint destruction. However, arthroplasty is also a common operation for adult cancer survivors who suffer from arthritis or who complain of worsening joint function years after treatment ends. Patients who have undergone joint replacement at an early age are likely to have to undergo repeated surgery in the future. Early diagnosis and treatment of avascular necrosis is important to prevent or delay arthroplasty.

Managing Avascular Necrosis: Tips for Patients and Families

Know your risks. Talk to your doctor about the patient’s cancer treatment (including doses received) and other risk factors.

Monitor your symptoms and get recommended tests. Seek medical attention if you develop pain or problems with your joints, especially if symptoms have not been observed before or if they worsen. Once your treatment is over, ensure that bone health is adequately addressed in your rehabilitation plan.

Stay physically active. Adjust your physical activity to reduce weight bearing and pay attention to pain as it will tell you what level of activity is acceptable. Avoid activities that involve pushing and falling, as well as contact sports – take care of bones and joints. If you’re not sure if a particular sport is okay to play, ask your doctor or physical therapist.

Wear shoes that provide support and use your prescribed orthoses and assistive devices. This is important as it helps to maintain proper joint alignment and function. Proper footwear also helps prevent falls and joint injuries.

Bone health and overall well-being depend on a healthy lifestyle:
Eat healthy foods, stay physically active, maintain a healthy weight, and don’t smoke.

–
Modified January 2019

Avascular necrosis. Description of the disease, methods of treatment

Avascular necrosis (osteonecrosis or bone infarction) is the death of bone tissue due to blockage of the blood supply. Hematopoietic cells are most sensitive to low oxygen levels and are the first to die after reduced blood flow (usually within 12 hours). This starts the process of bone marrow death and subsequent destruction of the entire bone.

The most common is avascular necrosis of the femoral head. Basically, the hip joint suffers from a combination of unreliable blood supply and high stress in this area while standing.

Symptoms and causes of avascular necrosis of the femoral head

At the initial stage of the disease, symptoms do not appear. Gradually, joint pain may develop, limiting the ability to move. With a complication, there is a risk of destruction of the bone or the nearby surface of the joint.

Major risk factors are bone fractures, hip dislocation, alcoholism and high dose steroid use. Sometimes, avascular necrosis can develop as a side effect of radiation therapy, chemotherapy, or organ transplantation. Osteonecrosis is also associated with diseases such as cancer, lupus, sickle cell anemia, HIV infections, Gaucher’s disease, and decompression sickness.

Examination for avascular necrosis of the femoral head

In the early stages of avascular necrosis of the bone, bone scintigraphy and MRI are the preferred diagnostic methods. X-rays at this stage of the disease often show no abnormalities. In the later stages, the picture looks less transparent than usual.

Treatment of avascular necrosis of the femoral head

Various methods are used to treat avascular necrosis of the femoral head. The most common approach is a total hip replacement.

Endoprosthetics for avascular necrosis of the femoral head is an effective method for the elderly. When installing a prosthesis in young patients, over time, a second operation may be required due to the expiration of its expiration date.

Other treatments include bisphosphonates. These are drugs that slow down the rate at which bone breaks down. Sometimes decompression (tunnelization) of the core of the affected hip bone is performed. The internal pressure of the bone is relieved by drilling a hole in it and implanting living bone tissue and an electrical device to stimulate new vascular growth.

A microvascular free fibula graft can also be placed for avascular necrosis. In this procedure, a portion of the fibula, along with its blood supply, is removed and transplanted into the head of the femur.