Outside MRI from Dec 2021, CT last week
MRI findings thought to be suggestive of osteoid osteoma.
CT features seem to favor OCD. What do you think?
[image: Knee 27F 13mos pain.jpg]
[image: Knee 27F 13mos pain (1).jpg]
[image: Knee 27F 13mos pain (2).jpg]
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[image: Knee 27F 13mos pain (4).jpg]
[image: Knee 27F 13mos pain (5).jpg]We commonly see chondral fissuring /
defects and subchondral BME in this location…..which strikes me as odd,
since it is so far posterosuperior—non-weight bearing surface, so there
might be contact in flexion.
Certainly plenty of muscle and fat to protect from extrinsic impact injury.
If this is a chronic OCD, the CT features suggest it is chronic /
stable…which seems a disconnect with the degree of BME (though the MRI is
from 3 months ago).
I don’t see a central mineralized sequestrum, as we often do in oo….but
my understanding is that we might not?
The MRI seems to demonstrate a full thickness chondral defect in the same
location—but is it possible that is focal bright signal related to a
nidus??
Bottom line…can we be certain that this is OCD rather than OO based on CT
and MRI findings?
Thank you for your help.
Hilary
1 thought on “Please Help, Knee MRI 27F 13 months pain”
hilary.umans
The majority favor OCD, though there were those who either favored oo or
did not feel confident that it could be ruled out.
Some mentioned the absence of sclerosis as an argument against oo….but it
is intra-articular, so I do not expect much, if any sclerosis.
The bright signal chondral defect was the primary finding cited by most
respondents in favor of OCD…..though my initial question (which nobody
addressed…so I guess they dismissed it) was whether or not a nidus could
mimic a chondral defect (I suppose they did not think so).
What I found most convincing, in favor of OCD….thanks to Hamza Alizai and
Lucas da Gama Lobo, is the point that there is no synovitis…..and, if
this were an intra-articular oo, we would expect alot of reactive synovitis.
Brian Howard pointed out that this is an area prone shear/impaction in the
hyperflexed knee.
Volker Lapcynski mentioned that he has had several patients with changes in
this location who had been working out with the leg press machine.
did not feel confident that it could be ruled out.
Some mentioned the absence of sclerosis as an argument against oo….but it
is intra-articular, so I do not expect much, if any sclerosis.
The bright signal chondral defect was the primary finding cited by most
respondents in favor of OCD…..though my initial question (which nobody
addressed…so I guess they dismissed it) was whether or not a nidus could
mimic a chondral defect (I suppose they did not think so).
What I found most convincing, in favor of OCD….thanks to Hamza Alizai and
Lucas da Gama Lobo, is the point that there is no synovitis…..and, if
this were an intra-articular oo, we would expect alot of reactive synovitis.
Brian Howard pointed out that this is an area prone shear/impaction in the
hyperflexed knee.
Volker Lapcynski mentioned that he has had several patients with changes in
this location who had been working out with the leg press machine.
Thanks to everyone who has responded.
HIlary
On Fri, Mar 18, 2022 at 10:16 AM hilary umans <hilary.umans@gmail.com>
wrote:
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