AVN means tissue death (“necrosis”) due to loss of blood circulation (“avascular”). It’s an uncommon disease of the hip joint, & rarely of the knee or shoulder. It causes ongoing chronic pain that gets worse, eventually destroying the joint.
The main risks for AVN are:
- Steroid Use (glucocorticosteroids; not the “anabolic” kind athletes use for performance enhancement). Patients have usually taken more than 20 mg of Prednisone daily for at least several months (as used for Lupus and other such diseases), not brief courses as given for Asthma, etc.
- Alcohol: at least 2-3 drinks per day increases the risk; the risk increases along with greater quantity. One drink = 1.5 shots of whiskey, 5 oz. wine, 12 oz. of beer.
- Sickle Cell Disease: AVN is very common among persons with actual Disease, not those with sickle cell “trait”.
- HIV Infection: Usually advanced disease, bordering on or actual AIDS.
- Transplantation (of organs): Likely related to use of steroids or other medications that suppress the immune system.
- Acute Lymphoblastic Leukemia: Related to chemotherapy that cures this fatal illness.
We worry about actual joint disease when passive movement causes pain; this means that the patient is totally relaxed, & the examiner wiggles, bends, & stretches it. Most people with “hip pain” have normal joints. See Musculo-Skeletal Pain for how to identify the anatomic structure involved, like bone, joint, ligament, tendon, muscle, bursa, etc. See also Arthritis for other causes of joint disease.
Diagnosis of AVN is made by x-ray. In the earliest stages, an MRI is more accurate. Since AVN often involves both hips (knees / shoulders), we check both sides. Anyone with both hip and also shoulder/knee pain should have x-rays, and an MRI of the hips.
There are various treatments for early-stage AVN, but they don’t work well. Almost everyone with the disease winds up needing a hip replacement.