Google is your friend.
1. Copy the words "avascular necrosis"
2. Go to google.com
3. Paste the words "avascular necrosis" into google search bar
4. Click "search"
5. Select any search result, and read
Here's what I found out,
using the aforementioned system:
Definition:
Avascular necrosis (also osteonecrosis, bone infarction[1], aseptic necrosis, ischemic bone necrosis[2], and AVN) is a disease where there is cellular death (necrosis) of bone components due to interruption of the blood supply.[3] Without blood, the bone tissue dies and the bone collapses.[2] If avascular necrosis involves the bones of a joint, it often leads to destruction of the joint articular surfaces (see Osteochondritis dissecans).
Causes:
There are many theories about what causes avascular necrosis. Proposed risk factors include alcoholism,[4] excessive steroid use,[5] post trauma,[6][7] caisson disease (decompression sickness),[8][9] vascular compression,[10] hypertension, vasculitis, arterial embolism and thrombosis, damage from radiation, bisphosphonates (particularly the mandible),[11] sickle cell anaemia,[12] and Gaucher's Disease.[13] In some cases it is idiopathic (no cause is found).[14] Rheumatoid arthritis and lupus are also common causes of AVN. Prolonged, repeated exposure to high pressures (as experienced by commercial and military divers) has been linked to AVN, though the relationship is not well-understood.
Prognosis:
The amount of disability that results from avascular necrosis depends on what part of the bone is affected, how large an area is involved, and how effectively the bone rebuilds itself. The process of bone rebuilding takes place after an injury as well as during normal growth.[24] Normally, bone continuously breaks down and rebuildsold bone is reabsorbed and replaced with new bone. The process keeps the skeleton strong and helps it to maintain a balance of minerals.[24] In the course of avascular necrosis, however, the healing process is usually ineffective and the bone tissues break down faster than the body can repair them. If left untreated, the disease progresses, the bone collapses,[2] and the joint surface breaks down,[14] leading to pain and arthritis.[14]
Notable individuals affected:
Avascular necrosis cut short the football and baseball careers of star athlete Bo Jackson.[28]
Other sports stars with this condition are former NFL running back Garrison Hearst, cyclist Floyd Landis, NFL quarterback Brett Favre, professional wrestler "Superstar" Billy Graham, wrestler Joe Heat, Number one draft pick for the Minnesota Lynx: Ben Dvorak, NBA player Jorge Garbajosa, NHL goaltender Ray Emery and gymnast Jade Barbosa.
In addition to the athletes listed, AVN has affected Edward Van Halen, lead guitarist for the rock band Van Halen, Ed Graham, drummer of the bands The Darkness and Stone Gods, and Micky Dolenz, the drummer/singer of the band The Monkees.
Recent research into the cause of death of Tutankhamun suggests that it may have been a factor in the pharaoh's death.
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There's no telling how far Micky Dolenz could have gone had AVN not ravaged his career.