Avascular necrosis is the breakdown and death of bone tissue due to insufficient blood supply. It’s a common complication of sickle cell disease, but early diagnosis and treatment can help slow progression.

Avascular necrosis (AVN), aka osteonecrosis, is a condition in which blood supply to your bones is interrupted, leading to bone damage and death (necrosis) of bone tissue. AVN can cause severe pain and mobility issues, particularly in the hips and shoulders.

Though rare in the larger population, AVN is common among people with sickle cell disease (SCD). Read this article to understand how AVN and SCD are related and what you can do to protect your bones if you have SCD.

The lack of blood flow to the bones is the main cause of AVN in people with SCD.

In SCD, red blood cells become sticky, rigid, and shaped like the letter C (or a sickle). These unhealthy cells tend to accumulate in smaller blood vessels, which can reduce or block the blood flow.

This blockage prevents oxygen and nutrients from reaching the bone tissues, which can cause the bone cells to die, leading to AVN. Over time, the bone may collapse, causing further complications.

The hip joint is the most common location of AVN, but it can also occur in the:

  • shoulders
  • knees
  • ankles
  • wrists
  • hands
  • feet

If you or your child have SCD, it’s important to watch for signs of AVN. Early symptoms of AVN might not be very noticeable, but as the condition progresses, you may experience the following:

If you or your child experiences any of these symptoms, be sure to speak with a doctor who manages your SCD. Early detection and treatment can help prevent further bone damage.

At what age does avascular necrosis occur in people with sickle cell disease?

AVN most commonly develops in people after the age of 30 years. But in people with SCD, it’s more likely to develop at a younger age.

SCD is the most common cause of AVN in the femoral head (part of the hip) in children and teenagers.

Sickle cell anemia (SCA) is the most common type of SCD, and people often use the terms interchangeably. People with SCA are more likely to develop AVN at an earlier age than people with other types of SCD.

To confirm AVN, a doctor will first perform a physical exam and ask questions about your or your child’s medical history.

Doctors will typically use X-ray imaging to check for damage to bones and joints. However, signs of AVN may not show up on an X-ray in the early stages of the disease.

Experts recommend MRI imaging to detect early signs of AVN due to its higher sensitivity.

Treating AVN in people with SCD involves several approaches, depending on the severity of the condition and the affected joint:

  • Medications: Anti-inflammatory drugs and some other pain relievers can help manage pain and reduce inflammation in the affected joint. A doctor might also prescribe medications to help improve blood flow to the bones.
  • Lifestyle changes: Avoiding activities that put stress on the affected joint can help prevent further damage.
  • Physical therapy: Exercises that improve range of motion and strengthen the muscles can help reduce pain and improve mobility. A physical therapist can design a personalized exercise plan that improves your strength without putting too much stress on the affected joints.

In more severe cases of AVN, a doctor may recommend surgical options, including:

  • Core decompression: removal of the core of a bone
  • Osteotomy: reshaping of the bone
  • Arthroplasty: aka joint replacement

The outlook for people with AVN due to SCD varies depending on the severity of the condition and how doctors can diagnose and treat it. Early treatment can help manage pain, maintain joint function, and prevent further bone damage.

Rarely, with proper medical care, AVN can eventually resolve.

However, without treatment, AVN can lead to joint collapse and severe mobility issues.

Regular check-ups with a healthcare professional are crucial to monitor your condition and adjust your treatment plan as needed.

How common is avascular necrosis in people with sickle cell disease?

The risk of developing AVN increases with age. In an often-cited study from 1991, as many as half of people with SCD can develop AVN in the femoral head (the most common site) by the time they turn 35 years old.

More recent research suggests that 22% of people with SCD develop AVN in the femoral head. Subjects in the study with AVN had a median age of 27 years at diagnosis, meaning half were older than 27 years and half were younger.

What are the stages of avascular necrosis?

AVN progresses through several stages:

  • Stage 1: mild symptoms, no visible damage on X-rays
  • Stage 2: bone starts to show signs of damage, but the shape remains intact
  • Stage 3: more significant bone damage and changes in the shape of the bone
  • Stage 4: bone collapse and severe joint damage, often requiring surgery

How fast does avascular necrosis progress?

The speed of AVN progression varies from person to person. Some people may experience rapid progression within a few months, while others may have a slower progression over several years. Early diagnosis and treatment are key to slowing the progression.

Is avascular necrosis an emergency?

AVN is not typically an emergency, but it is a serious condition that requires prompt medical attention. If you experience sudden, severe pain or a significant loss of joint function, you should seek medical help immediately.

Regular check-ups, early diagnosis, and appropriate treatment can help you manage AVN effectively and maintain a good quality of life. Stay proactive, communicate with your healthcare team, and follow their recommendations to keep your bones healthy and strong.