Bone is a living tissue. It requires a constant blood supply to stay alive. When the blood supply to the bone is interrupted, it leads to the death of bone tissue or Avascular Necrosis (AVN), or Osteonecrosis.

In simple terms, AVN is like a heart attack or myocardial infarction. The loss of blood supply to heart muscle leads to a heart attack and cardiac muscle cell death. The same is true for bones. If the blood flow to the bone is interrupted, the bone begins to die.

Avascular Necrosis (AVN) is also known as Aseptic Necrosis or Bone Infarction.

The common causes of AVN include:

• Injury
• Regular alcohol consumption
• High dosage of corticosteroids
• Certain conditions like Gaucher’s disease, Sickle cell anemia, etc.
• Chemotherapy
• Idiopathic (unknown cause)

Trauma is the leading cause of AVN followed by idiopathy.

The ankle joint consists of three bones:

• The tibia or shin bone
• Fibula
• Talus

In the case of ankle AVN, the talus is most frequently affected.

Avascular necrosis of the ankle can lead to a total loss of the ankle joint, arthritis, ankle deformity, and pain.

In the early stages, AVN usually doesn’t have symptoms. But as the disease gets progresses, the symptoms become more prominent.

Initially, it might only hurt while bearing weight on the affected leg. Then, pain may become constant. If the bone and surrounding joint collapse, it may lead to severe pain that makes it unable to use the joint.

The most common symptoms of AVN of the ankle are pain, swelling, immobility, and limping while walking.

The duration between the first symptoms and bone collapse can range from several months to more than a year.

Diagnosis of avascular necrosis of the ankle may involve:

• MRI
• X-ray
• CT Scan

The treatment of avascular necrosis of the ankle involves:

• Blood thinners:
  Blood thinners are prescribed in case there are blood clots present.
• Nonsteroidal anti-inflammatory drugs (NSAIDs)
  NSAIDs help in reducing the pain.
• Cholesterol-lowering drugs
  These drugs reduce the cholesterol level in the blood which helps in preventing blockages in the blood vessel.
• Physiotherapy
  It involves certain exercises to increase the mobility of the joint.

• Core Decompression:
  A surgical procedure in which a hole is drilled in the talus, which may lead to decompression of the bone and increase the blood supply to the talus. It can only be used at the early stages of AVN.
• Ankle Fusion
  When arthritis of the ankle joint occurs after AVN and talus fracture, a fusion of the ankle may be recommended. Ankle fusion is an irreversible technique. It often leads to abnormal motion and limping, which results in degenerative arthritis of the adjacent joints. Therefore, alternative treatments are desirable.
• 3.Regenerative Medicine and Stem Cell Therapy:
  Stem cell therapy involves the use of mesenchymal stem cells to treat various conditions. Unlike ankle fusion, stem cell therapy allows the patients to resume physical activity soon after the treatment. Several athletes have successfully undergone stem cell therapy for AVN of the ankle.