This is a 72M who was previously imaged elsewhere (that MRI is not available) and diagnosed with a SONK-Like lesion of the LFC in December.
He improved somewhat but had recent, recurrent severe knee pain without trauma history. This MRI is Now.
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I think the posterolateral location and appearance of this lesion is atypical. I don’t recall seeing these parallel suchondral dark lines. There is not subchondral “dark area”. The articular contour is smooth.
Would you call this SIF? Is this recurrent SIF? Is there any suggestion of AVN?
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When we see these in the medial compartment, there is almost always degenerative meniscus tear…but the meniscus looks normal here. Why did this happen here?
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The referrer asked me what I know about outcomes of Intraosseous Bioplasty. I know I’ve seen some presentations a while ago, but have no real knowledge about this. Do you?
Tetyana Gorbachova gave a brilliant lecture this AM on Subchondral Lesion Nomenclature—-I clearly have to watch it again.
Highly recommended buff.ly/3hVw4IK
Hilary Umans
Tetyana agreed to have me share her thoughts on this case:
My thoughts:
Yes, it’s a SIF ( subchondral lines running close to bone plate, no hx of trauma)
No evidence of collapse yet.
Not a primary osteonecrosis (aka AVN) as the lines here are running through the edema-like signal, some lines are incomplete, they don’t encircle a distinct marrow area. Although on some slices it may seem that they outline a distinct region of marrow , AVN-ish like, but the difference is that it is not a complete outline, its open-ended; also the marrow in those regions is edematous in sync with the marrow on the other side of the line . Primary ON is typically sitting there looking pretty without edema till collapse happens and synovial fluid gets to it.
BUT if this SIF goes on and can’t heal, the patient will likely develop secondary osteonecrosis and we see dark thick subchondral area and later collapse.
Why there ?
2 possibilities : 1) unusual occupation /activity (deep squatting , elliptical, stairs) or 2)(I favor this one!) is that this a case of TBMES (transient bone marrow edema syndrome) in the knee, manifesting as edema like signal + SIFs. The handful of cases I have personally seen all share that the menisci and cartilage look pristine, no trauma hx, and I did see regions of edema in several locations in the same knee or different knees simultaneously or several points in time. And it is in those cases that I have seen several parallel fracture lines ( but hands down none as spectacular as your case)!! It is on a basis of those rare cases that I became a believer that TBMES exists as a separate entity , frequently resulting in SIFs but not synonymous with it.
So the general principles of SIF work here with SIF in setting of TBMES as well: if no collapse , if subchondral area (when present) is not thick and long, if no cartilage loss and no meniscal tear- those are likely reversible with protected weigbearing.
I don’t have experience with subchondroplasty. The literature states improvement of pain , but unclear what MRI findings predict its success or failure .
*** I have discussed this with the referrer and recommended protected weightbearing and follow up MRI in 3 months, hoping for healing.
I have also suggested DEXA, on the off chance that his osteoporosis is generalized.