The Different Stages of Osteonecrosis (Avascular Necrosis)

I’ve noticed, from reading the statistics of my site, that a lot of people are trying to find out information about the different stages of osteonecrosis (avascular necrosis). Most stages are based on ON(AVN) of the hips, as those are the joints most commonly affected. However, as I have mentioned on this site, any joint can be affected by ON (AVN). The second most common joints affected are the knees.

There are the Ficat and the Steinberg Classification systems. Most orthopedic doctors use the Ficat classification system to determine at what stage your disease is. The stages are as follows:

Stage I: 

  • X-Ray: ON (AVN) is not detectable.
  • MRI: there might appear slight bone marrow edema or joint effusion. Joint effusion most commonly appears in the knees.
  • Bone Scan: evidence of increased uptake. Increased uptake is mainly due to increased activity of osteoblasts (cells responsible for bone formation) associated with new bone formation, and to a lesser degree by increased blood flow to bone. Increased uptake is an indication that there might be a tumor, fracture or infection.

Stage II:

  • X-Ray: mixed osteopenia, a condition where bone mineral density is lower than normal, or evidence of sclerosis.
  • MRI: evidence of lesion; an abnormality in bone tissue.
  • Bone Scan: increased uptake (see note above).

Stage III:

  • X-ray & MRI: bone collapse of joint appears imminent.

Stage IV:

  • X-ray & MRI: collapse of joint.

Image taken from the Journal of the American Academy of Orthopaedic Surgeons

To learn more click here: Ficat Classification and Steinberg Classification

A lot of websites, talking about Ficat Classification, refer to the level of pain at each stage of the disease. One indication of early ON (AVN) in the hips is pain in the groin. However, it appears to me that the pain differs from one ON (AVN) sufferer to another. My ON (AVN) is in my distal femurs and the first time I felt pain was in my knee caps.  As the disease worsened the pain ran like hot rods up and down my thighs. Every body is different.

4 thoughts on “The Different Stages of Osteonecrosis (Avascular Necrosis)

  1. I have stage IV osteo-necrosis bi-laterally. If your reading this,; you’ll understand ;that,YOUR PAIN levels will increase with time. I URGE YOU to NOT WAIT on the INEVITABLE surgery. Please don’t suffer the waiting. Believe me, IT IS NOT WORTH IT AT ANY COST. Sincerely Ray Z…….ps;Please don’t entertain waiting. Take my advice have the replacement surgery the cost is TOO HIGH for anyone to endure. I hope you consider my advice and don’t suffer like I did!!!

    • Bill,

      Where do you have AVN? What stage are you at? Are you seeking treatment? Thank you for checking out my site. The diagnosis of AVN can be very scary, but there is a great community out there and everybody is so open about sharing their own experiences concerning surgeries, doctors etc. Feel free to ask questions. Good Luck!

  2. This chart was so helpful. Thank you for posting it. I’m guessing I’m stage 2 from the look of my Xray. I hope that will make me eligible for stem cell treatment. I’m 40 and a mom of 4.5 yr old twins with a really active life. The thought of THR after already having 2 surgeries is most undesirable. Has anyone had stem cell treatment as a result of fracture and seen success? Thanks so much. Lyndsay

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