MR Imaging: Some Specific Lesions
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Now let's talk briefly about Ye's triad.
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Ye's. Uh, triad related typically
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to antral medial rotary instability associated
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with flexion valgus
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and external rotation of the tibia is not a great taste
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to show you, but this is taken from the internet.
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Here we can see a female basketball player.
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Here's the case that I'm talking about,
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twisted her knee awkwardly after receiving a long pass
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and turning to the basket.
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And you can see in this particular position shown in the
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internet, uh, photograph, there is external rotation
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of the tibia and findings consistent with ous triad.
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Those findings are an injury of the ACL, often acute
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and complete, um, MCL injury that often is high grade
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or a complete and a medial meniscal injury
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or mani medial, uh, meniscal capsular injury.
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All right, those are the classic ous triad.
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I can tell you that when you look at cases of ous triad,
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you often will see a fourth component,
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let's call it the tetra.
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And that particular component is a tear at the femoral
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attachment of one
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of the patello femoral ligaments on the medial side,
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the most important one,
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a medial patello femoral ligament tear or evulsion.
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That does not mean that there was a patellar dislocation.
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So this is an Ute Tetra,
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and I would say there may in fact be a penad pointed out in
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several articles with a higher frequency of tearing
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of the lateral meniscus.
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So in this example, again, an old one, an ACL tear,
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a medial collateral ligament, uh, injury, a medial, uh,
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meniscocapsular injury, a tear
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of the medial patello femoral ligament,
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and a lateral meniscal tear.
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An ue penta.
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Another interesting case would be that
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of stump entrapment.
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All right, and let's look at that.
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And again, I don't, okay,
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something popped up but it went away.
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That's good stump entrapment.
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It's something that occurs
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with complete tears involving the proximal portion
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of the anterior crusade ligament.
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What may occur is that is anterior retraction
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of the torn fibers that can lead to entrapment
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of the torn fibers
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and a decrease in extension of the knee.
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So this is called stump entrapment.
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Now, possibly stump entrapment may lead to the subsequent
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development of focal arthrofibrosis
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in the general spectrum of a
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Cyclops lesion.
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Now, I know we think of cyclops lesion,
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and you're going to hear a bit about it.
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We think of that as occurring following ACL reconstructions,
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but it is described in cases of ACL Tears,
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typically high grade
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or complete without surgery being performed.
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And it's even described as a finding following other types
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of arthroscopic surgery.
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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