Avascular Necrosis (AVN)

Avascular Necrosis


The condition resulting from the death of bone tissue due to lack of blood supply is called avascular necrosis (AVN). It leads to small breaks in the bones leading them to collapse. AVN occurs due to long-term use of high-dose steroid medications and excessive alcohol intake. AVN leads to joint pain and permanent joint damage. AVN generally affects the femoral and humeral heads and the femoral condyles and is most commonly encountered in the hip. Most patients arrive late for treatment as it presents late in the disease course, thus leading to joint destruction within 5 years.

What are the Symptoms of AVN
The symptoms are not presented in the early stages of the disease and the condition worsens when the affected joint hurts with lots of weight on it. Pain gradually develops from mild to severe. Pain associated with AVN of the hip might have the focus points in the groin, thigh, or buttock. Shoulders, knees, hands, and foot are also affected by AVN of the hip.

What are the Causes of AVN
Joint or bone trauma, cancer treatments that weaken bone and harm blood vessels, fat deposits blocking small blood vessels that feed the bones, sickle cell anemia and Gaucher's disease that cause diminished blood flow to the bones are the various possible causes of AVN.

Some more risk factors for AVN are as follows:

  • High-dose corticosteroids increase the lipid level in blood, thereby reducing the blood flow
  • Excessive alcohol use causes fatty deposits in blood vessels
  • Pancreatitis
  • Diabetes
  • Systemic lupus erythematosus

  • How is AVN Diagnosed?
    The first stage diagnosis involves a physical examination. A physician presses around the joints to check for tenderness. The doctor might also move the joints to varied directions to check the flexibility to movements.

    Secondly, imaging tests are performed to pinpoint the source of pain, thereby diagnose AVN. X-rays, MRI, CT scan, and bone scan are some of the diagnostic techniques that show early changes in the bone.

    Pathophysiology of AVN
    In AVN, blood supply to a bone is affected by direct trauma (fracture, dislocation), non-traumatic stress, and increased levels of serum lipid deposition in the femoral head leading to femoral hypertension and ischemia, and fracture. Early features of AVN are necrosis of hematopoietic cells and adipocytes followed by interstitial marrow edema. Approximately 3 hours after oxygen deprivation, osteocyte necrosis occurs.

    How is AVN Treated?
    Death of cells can never be cured and hence there is no treatment for AVN. Progression of AVN can be prevented and analgesics are used as pain relief. Some of the medications used to treat AVN include nonsteroidal anti-inflammatory drugs, cholesterol-lowering drugs, and blood thinners. In most cases AVN is not presented until it is fairly advanced, surgery is recommended than medication.

    Stem Cells in AVN Treatment
    AVN is the necrosis of cells in the affected bone. Hence growing the lost tissues to remodel the affected area is a successful method. Mesenchymal stem cells having osteogenic and angiogenic properties will be injected in combination with PRP will reduce inflammation and regenerate the necrotic nip bone. Mesenchymal stem cells can be transplanted to the area of osteonecrosis, results in the reduction of pain that coincided with a decrease in the necrotic volume within the femoral head. Patients with early stage disease showed results indicating an increased Harris Hip Score and a decrease in the size of necrotic lesions.