Diagnostic Considerations
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Finally, let me just indicate one of the ways I assess
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the distribution
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and severity of injuries
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to the medial supporting structures.
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I go to my axial images
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and I remember the broad anterior third, the middle third,
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and the posterior third,
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and I try to decide where is the edema.
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So if we're dealing with edema involving mainly the anterior
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third, but extending to the region of the middle third
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of the medial supporting structures,
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these are the considerations that I would have.
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Clearly one can have a lateral patella dislocation.
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You're going to hear more about that later today.
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And that can lead to injury not only of the medial reticulum
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and the RET macular ligaments,
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but also to injury of the tibial collateral ligament.
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And here's what that would look like
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with edema in the anterior third and middle third.
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I also, with this distribution, looked for injuries both
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of the medial patello femoral ligament
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and the tibial collateral ligament.
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This may be seen without a patellar dislocation,
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but with a valgus injury to the knee.
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So here we can see such a case. It's an old case.
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Images are not pretty,
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but they show you the edema involving the anterior third
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and middle thirds of the medial supporting structures.
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And then rarely, you may see
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a similar appearance when there is a fluid leaking from the
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pre patella bursa.
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And this is an example showing you, again, this sort of
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distribution of edema
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or fluid in this case related to bursitis.
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If we look at the second scenario
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where we have edema mainly involving the posterior third,
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perhaps extending up to the uh, middle third,
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these are the two things that I think about
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an injury involving both the tibial collateral ligament
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and posterior bly ligament as shown in this case
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with edema involving the central
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and posterior thirds of the medial supporting structures.
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And then the final thing I always think about, am I dealing
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with a popliteal cyst that is leaking fluid,
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that is extending medially around the posterior third
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and sometimes middle third
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of the medial supporting structures?
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So those are helpful points I think, in terms
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of differential diagnosis.
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So what I've done in my allotted period of time is
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to cover these two particular objectives.
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We studied the middle of the medial supporting structures,
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we divided them into thirds
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or uh, regions, anterior, middle, and posterior.
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And we looked at the various alterations that can be seen,
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including not just soft tissue but bone abnormalities.
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Uh.
Donald Resnick, MD
Professor Emeritus, Department of Radiology
University of California, San Diego
Mini N. Pathria, MD, FRCP(C)
Division Chief, Musculoskeletal Imaging
University of California San Diego
Eric Y. Chang, MD
Adjunct Professor, Radiology
University of California, San Diego
Brady K. Huang, MD
Clinical Professor of Radiology
UC San Diego Medical Center
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