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Avascular Necrosis of the Knee

Mar 19, 2013

Knee Avascular Necrosis

Tampa, Saint Petersburg and Clearwater Fl


av knee 2
Spontaneous osteonecrosis of the knee

Avascular necrosis (AVN) also referred to as osteonecrosis of the knee can be a debilitating progressive disease of the knee in which the subchondral bone loses vascular supply and a portion of the bone dies.  This can lead to subchondral collapse resulting in severely erosive degenerative arthritis.  Initially, it was felt to be a disorder that involved predominantly the medial femoral condyle of the knee.  Now, researchers have expanded the concept to include three distinct pathological entities:

  1. Spontaneous AVN or osteonecrosis.
  2. Secondary AVN or osteonecrosis.
  3. Post arthroscopic AVN or osteonecrosis.

Idiopathic or Spontaneous osteonecrosis has an unknown etiology.  However, there are many theories including interruption of the arterial supply, capillary occlusion, interosseous capillary tamponade, or injury to a vessel wall.  There is some controversy that It occurs more frequently after age 50, and is much more common in females. Nearly three times more females than males are afflicted. Spontaneous AVN is mostly seen in the epiphyseal region. In the knee this is generally seen in the medial or lateral tibial plateau, or in the medial or lateral femoral condyle. Spontaneous AVN also has been seen following a du corgi la insufficiency fracture.‏ Secondary avascular necrosis may involve both femoral condyles with multiple lesions in the epiphysis, metaphysis, and diaphysis of the bone.  Usually, this occurs in the younger subset less than 45 years of age and may be bilateral in greater than 80% of the time.  Risk factors for secondary avascular necrosis include radiation, chemotherapy, and also trauma.  Medical disorders such as myeloproliferative diseases, sickle cell disease, are associated with increased risk of AVN.  Indirectly, there is a correlation between corticosteroid use; however, close examination of the data on corticosteroid use is conflicting and it may be similar to alcohol use in that it is inconsistent and that sometimes very little quantities are associated with this. Not all patients who have large doses of corticosteroids develop this similarly to the risk factor for alcohol use, as avascular necrosis only occurs in 10% of patients on high dose corticosteroids and in a much lower percentage in the general population that abuses alcohol.

If you’re in pain or had an injury and are looking for an alternative to surgery, contact us immediately at one of our locations. Our Main Medical Center located in Tampa Bay, Florida (727) 462-5582 or at Beverly Hills, California (310) 975-7033.

Picture of Dr. Lox in his office

About the Author

Dennis M. Lox M.D. is an internationally renown Sports and Regenerative Medicine specialist. Dr. Lox incorporates Regenerative Medicine techniques such as cell science applications, Platelet Rich Plasma (PRP), and Tissue Engineering aspects, to help patients from around the world with a vast array of problems. Dr. Lox is board certified in Physical Medicine and Rehabilitation. Dr. Lox lectures extensively and has edited two PM&R textbooks, the prestigious A State of the Art Review (Star) on Low Back Pain, and Soft Tissue Injuries: Diagnosis and Treatment.

Dennis M. Lox M.D. maintains an active practice in the Tampa Bay, Florida area, and in Beverly Hills, California.