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Avascular Necrosis of the Femoral Head

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What is Avascular Necrosis (AVN) of the Femoral Head?

Avascular necrosis (AVN) occurs when bone dies because it doesn't get enough blood flow. The femoral head is the “ball” of the ball-and-socket joint in your hip.

The thighbone (your femur) fits into the cup-shaped socket of your pelvis. Muscles, tendons, and ligaments hold the joint in place.

Without enough blood flowing to this joint, the bone dies and the joint weakens resulting in bone necrosis.

Other names for avascular necrosis (AVN) include:

  • Osteonecrosis
  • Aseptic necrosis
  • Ischemic necrosis

Avascular necrosis causes and risk factors

AVN often occurs in long bones like the femur. Unlike other bone disorders, this happens most often in men between age 40 and 50.

Untreated injuries and diseases can cause AVN.

Other causes include:

  • Injury, such as a major impact from an accident or during sports.
  • Complications of a hip fracture or dislocation.
  • Blood clots or inflammation.
  • Legg-Calve-Perthes disease (in children).

Avascular necrosis (AVN) risk factors include:

  • Sickle cell disease.
  • Gout.
  • Lupus.
  • Long-term use of corticosteroids.
  • Heavy alcohol consumption over time.

AVN complications and prevention

Left untreated, AVN can cause the tissue in the hip joint to die. Eventually, the bone can collapse.

In some cases, drugs like corticosteroids can cause this condition to worsen.

If you've taken corticosteroids for a while, talk to your doctor about switching to a different medication to lower your risk of AVN.

The best way to prevent AVN is to maintain strength and flexibility. Be sure to warm up before any physical activity and include strength training in your workouts. 

Learn more about AVN and hip problems

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Avascular Necrosis (AVN) Symptoms and Diagnosis

AVN symptoms

In the early stages of this bone disorder, you may not display any symptoms.

As it progresses, you may have the following AVN symptoms:

  • Mild to moderate hip or groin pain.
  • Stiffness in the hip joint.
  • Pain while walking or when moving the hip.
  • A limp.

Aching can occur in the hip, groin, or buttock. You may also have pain in the knee.

For many people, rest helps relieve the pain.

AVN diagnosis

In most cases, an orthopaedic surgeon will diagnose AVN.

He or she will conduct a physical exam to check for pain and tenderness at the joint.

Your doctor may also order imaging tests to see the damage.

These tests include:

  • X-rays
  • MRI scan
  • Bone scan 

Learn more about AVN symptoms and tests

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Avascular Necrosis (AVN) Treatment Options

The first goal of AVN treatment is to prevent further damage to the hip and give the bone a chance to heal.

Avascular necrosis treatment also focuses on:

  • Targeting the cause of the AVN.
  • Fixing the problem.
  • Healing the joint.

Nonsurgical AVN treatment

Your doctor will first try conservative treatment for your AVN.

This means:

  • Crutches to limit how much weight you put on the hip joint.
  • Rest.
  • Physical therapy.

Electrical stimulation is another nonsurgical AVN treatment option. This provides electrical currents to help your body produce new bone.

Your doctor may also prescribe drugs, depending on the cause of your AVN.

These can include:

  • NSAIDs for pain.
  • Blood thinners to prevent clots.
  • Cholesterol-lowering medications.

Surgical AVN treatment

Sooner or later, most people with AVN need surgery as the condition worsens.

Surgical options for AVN include:

  • Bone graft — uses healthy tissue from another part of your body to rebuild the damaged hipbone.
  • Osteotomy — changes the shape of the bone to help move your weight off the bone.
  • Core decompression — removes part of the bone to let new blood vessels form.
  • Hip replacement — replaces the damaged parts of your hip joint with metal or plastic parts. 

Learn more about treatments for AVN and other hip problems

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