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  • The spectrum of hip OA and AVN

    Posted by heenadevk1119_462 on January 12, 2017 at 8:28 am

    How do you guys treat the advanced cases of hip osteoarthritis when, common being common, the natural history would be sclerosis and femoral head flattening or collapse? I see it unilateral, bilateral, and sometimes even the clinician asks about it when ordering — possibly because medications involved also might be coincidental.
     
    Maybe the question is, does hip OA actually lead to a “chronic AVN”? I’ve never really seen this treated in the literature or discussed much in fellowship or academic circles.
     
    Thanks in advance.

    Unknown Member replied 3 years ago 9 Members · 15 Replies
  • 15 Replies
  • Lee

    Member
    January 12, 2017 at 5:28 pm

    My thought is that if the patient is older and/or doesn’t have any increased risk for osteonecrosis, then OA is the “egg” here and the “chicken” is an insufficiency fracture, which can also cause subchondral collapse.
     
    We probably don’t pay it too much attention because 1) early on everyone is attributing the symptoms garden-variety OA and 2) by the time subchondral collapse occurs, it’s probably time for a new hip anyway.

    • rlegaul23_732

      Member
      January 12, 2017 at 5:37 pm

      AVN is NOT the natural history of OA.
       
      OA leads to sclerosis and femoral head flattening but not collapse in the same way that AVN leads to subchondral lucency and eventual collapse. The collapse in OA is more of a wearing out, as opposed to insufficiency.
       
      OA should not lead to an insufficiency fracture. It doesn’t make sense physiologically.

      • Riquelme10

        Member
        January 12, 2017 at 6:01 pm

        I suppose it might be impossible to differentiate a chronic Avn with late stage oa from primary oa but I don’t think it would be a necessary distinction to make. However, oa will not lead to avn. Usually I think you should be able to guess if its oa caused by avn because there will be some fragmentation of the femoral head

      • Lee

        Member
        January 12, 2017 at 6:02 pm

        Quote from SF410

        AVN is NOT the natural history of OA.

        OA leads to sclerosis and femoral head flattening but not collapse in the same way that AVN leads to subchondral lucency and eventual collapse. The collapse in OA is more of a wearing out, as opposed to insufficiency.

        [b]OA should not lead to an insufficiency fracture. It doesn’t make sense physiologically. [/b]

         
        Yeah, trying to make the chicken/egg analogy was a bad idea because it implies casuality. Really they’re just two very common conditions whose patient populations overlap.

        • Unknown Member

          Deleted User
          January 13, 2017 at 5:43 am

          How much the head is deformed, flattened, remodeled is my usual trigger for invoking AVN as etiology, and at that point it’s an academic exercise, isn’t it? Sidebar, how much of Milwaukee shoulder is AVN?

          • Unknown Member

            Deleted User
            January 13, 2017 at 8:17 am

            The point has been made above, but if it is advanced OA and all you have is a plain film-you can’t really exclude uNderlying AVN, but it doesn’t matter. That patient is headed for total hip.

            • heenadevk1119_462

              Member
              January 13, 2017 at 2:51 pm

              Thanks for the responses, didn’t really clear anything up unless my takeaway is like much of MSK otherwise, “doesn’t really matter.” Which I actually love about it.

              • Unknown Member

                Deleted User
                January 13, 2017 at 8:12 pm

                By far the most important thing in radiology is that your diagnosis leads to the proper management.  This isn’t exclusive to MSK radiology.
                 
                The management of Severe OA primary or secondary to AVN is eventually an arthroplasty so distinguishing between the two isn’t necessary.
                 
                I guess of interest is the fact that diseases such as SONK and TOH were originally thought to be secondary to avascular necrosis and then later found to originate from a subchondral insufficiency fracture. This proves that even the pathologists can’t figure things out.

                • amyelizabethbarrett28_711

                  Member
                  January 13, 2017 at 8:35 pm

                  Quote from clinicalcorrelate

                  By far the most important thing in radiology is that your diagnosis leads to the proper management.  This isn’t exclusive to MSK radiology.

                  The management of Severe OA primary or secondary to AVN is eventually an arthroplasty so distinguishing between the two isn’t necessary.

                   
                   
                  two thumbs up.

                  • Unknown Member

                    Deleted User
                    July 22, 2021 at 11:19 am

                    Femoral head subchondral insufficiency fracture vs avn? Is there a difference?

                    • cchandc

                      Member
                      July 22, 2021 at 12:15 pm

                      AVN and sun Honduras insufficiency fracture are different.

                      Etiology doesnt matter when its end stage because treatment is the same.

                      But you can get end stage OA and femoral head collapse from;
                      -AVN
                      -osteoporosis which leads to insufficiency fracture (normal stress on abnormal bone)
                      -abnormal force on normal bone
                      – Charcot arthropathy
                      – crystalline and inflammatory arthropathy

                      Probably a few others too

                    • Unknown Member

                      Deleted User
                      July 22, 2021 at 12:49 pm

                      Quote from hopefulradsfuture

                      AVN and sun Honduras insufficiency fracture are different.

                      Etiology doesnt matter when its end stage because treatment is the same.

                      But you can get end stage OA and femoral head collapse from;
                      -AVN
                      -osteoporosis which leads to insufficiency fracture (normal stress on abnormal bone)
                      -abnormal force on normal bone
                      – Charcot arthropathy
                      – crystalline and inflammatory arthropathy

                      Probably a few others too

                      TOH no fractures, 
                      both avn and insufficiency fractures can have subchondral collapse. How do you differentiate.

                    • cchandc

                      Member
                      July 22, 2021 at 2:26 pm

                      Some times you cant tell like if there is severe collapse and secondary OA.

                      In that case, the clinician could screen for osteoporosis (dexa) and do an X-ray and mr of the other hip. They could get a good history to see if they have risk factors for above etiologies.

                      Some of the times, i can look back on prior imaging (ct a&p, scout image of other MR studies)
                      to see if i can see the typical AVN appearance. Gets missed a lot on CTs done for other indications.

                      Other times, you may be able to see some findings of AVN still present (e.g. double line sign/geographic abnormality) if there isnt too much collapse.

                    • Unknown Member

                      Deleted User
                      July 22, 2021 at 4:31 pm

                      See this too, of course.

                      This is what I say:
                      Severe end stage arthropathy; which may be related to remote osteonecrosis.

                      It doesnt matter, as stated, but I cant help myself from suggesting it when that is my hunch.

                    • Unknown Member

                      Deleted User
                      July 22, 2021 at 5:04 pm

                      This case was not an end stage OA. Acetabulum and joint space were maintained.
                       
                      Double line sign and fatty center are an obvious case of avn.
                       
                      This case didn’t have these.
                       
                      So called early avn?
                       
                      [ul][*]diffuse edema: edema is not an early sign; instead, studies show that edema occurs in advanced stages and is directly correlated with pain- Radiopedia [/ul]  lots of femoral head edema extending into intertroch on my case
                       
                      Leaning toward insufficiency fracture