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Okay,

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let's go to a 15-year-old girl with a twisting

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injury while playing volleyball.

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Evaluate for anterior cruciate ligament tear.

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Let's do what we've done before.

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We'll stay consistent.

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We'll look at the axial.

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This time, the effusion is even bigger.

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The effusion is distending the capsule.

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It's an intermediate to higher grade effusion.

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If you want to call it a grade two or three

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out of four effusion, that would be fine.

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Here's the patient's normal embryologic plica

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reflection known as a septum residuale plica.

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Patient does not have plica syndrome.

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Everybody's got a plica.

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There's a normal web that can sometimes get

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entrapped between the medial facet of the patella

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and the medial facet of the femur.

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Not this time.

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Let's keep scrolling.

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We know this is lateral because the lateral

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facet is longer than the medial facet.

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Our trochlea is a little bit shallow.

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Our patella is well shaped.

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It's normally shaped.

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So, we have a little bit of trochlear dysplasia.

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There's no displacement of the patella.

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The anterior cruciate ligament,

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not so good.

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Remember, it should be a linear black structure.

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It's blown up like a balloon.

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The posterior cruciate ligament looks better.

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Now, I like my femoral notch to be about

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two to two and a half centimeters.

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This one,

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one and a half centimeters.

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So the patient has notch stenosis, or dysplasia.

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So, there is a component of femoral dysplasia

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which most people would not recognize.

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It's okay down here,

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but up high, narrow.

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Let's keep looking.

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How about the medial side?

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What's a little fat in there?

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It's a little gray in there.

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Lateral side, looks okay.

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Fusion goes around the back.

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Neurovascular bundle looks fine.

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Posteriorly,

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there's the popliteal artery,

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popliteal vein, popliteal nerve

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underneath that word compression.

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Let's move it so you can see it.

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There it is.

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Artery, vein, nerve.

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Okay.

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And you'll see the perineal nerve come to the

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tibial nerve to form this sciatic nerve.

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We're not high enough to get to the sciatic nerve,

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but here's your perineal nerve, right there.

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Okay, let's keep looking.

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Let's be consistent and put up

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our coronal and our sagittal.

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Okay, let's scroll.

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And we know right away we have a pivot shift.

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We got a posteromedial tibial

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microtubecular injury.

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We have a posterolateral microtubecular injury.

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We have a non-kissing osteochondral fracture

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of the femoral terminal sulcus.

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So, we know this has happened.

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Has there been varus or valgus?

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Well, we look at the coronal for that.

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The lateral collateral ligament includes

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the popliteus tendon and the hiatus,

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normal.

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Fibular collateral ligament,

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proximal origin,

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insertion with the bicep femoris as

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the conjoined tendon, normal.

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Medial side, A.B. normal.

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Abnormal.

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Medial collateral ligament,

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tibial collateral component,

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layer number two,

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wavy, detached.

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Abnormal.

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Meniscotibial ligament,

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layer three, normal.

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Coronary ligament is its synonym.

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Meniscofemoral ligament, ruptured.

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Layer three, affected.

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Call that 3A.

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Layer two affected.

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If layer two is affected,

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you don't have to look at layer one.

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It's affected.

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You can't affect layer two without affecting layer one.

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Save yourself some breath.

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Let's scroll the coronal because we can see

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the ACL in the coronal.

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There it is.

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And now it's pulverized.

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It's going that way.

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So you can diagnose an ACL tear

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off the coronal projection.

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ACL is transected.

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How about the sagittal projection.

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Once again, transected.

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Here's a stump.

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Right there.

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There's another stump right there.

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There's some tissue folded over

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on itself right there.

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So pivot shift, ACL transection.

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They were correct.

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Medial collateral ligament, torn.

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Grade 3A.

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Valgus.

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Pivot shift.

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Mechanism of injury with ACL

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transection and MCL tear.

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There's a hemarthrosis.

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Are we done yet?

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No, we're not done yet.

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We haven't checked the corners.

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Let's go to the posterolateral corner.

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The popliteofibular ligament is there.

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It's a little fuzzy right there.

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So it has got a partial tear.

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If it tears and it rolls up in a ball like this,

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and then you get a squiggly little end to it,

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and it doesn't connect.

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That's called the mermaid sign.

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Patient doesn't have that,

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but certainly has an injury right there.

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How about the meniscopopliteal fascicles?

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Oh, they're gone.

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The meniscus is floating anteriorly.

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If you wanted to call that

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a meniscocapsular separation,

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I wouldn't object.

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I'd rather call it a meniscovesicular detachment,

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laterally.

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Upper fascicle, gone.

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Lower fascicle, gone.

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It looks like a pile of dust.

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Let's keep going, shall we?

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Let's go to the posteromedial corner,

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not so bad.

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Maybe a little bit of swelling from this.

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From this.

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But look at the semimembranosus corner attachment.

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Direct head, fine.

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There's the pars reflexa of the semimembranosus.

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There are at least five components of it.

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Only two today.

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I am showing you the direct head and the pars reflexa.

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The two most important.

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Now, if you look very carefully,

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there is an extra little line here.

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And that extra little line is the interface

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of the meniscus with the capsule.

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And that is blood in the capsule.

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Right there.

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So the patient does have a ramp injury.

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Where's your posterior meniscotibial ligament?

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Right there.

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Kind of hard to see.

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So, very common to see is low grade

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meniscocapsular sprains, medially,

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ramps one through five.

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They can get more severe.

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Very common to see meniscovesicular detachment

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because you're translating

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when you pivot shift

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in association with anterior cruciate ligament transection.

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It's another finding.

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Let's check out the menisci.

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Medial meniscus, intrinsically normal.

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Let's check out the medial meniscus

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on the coronal.

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Intrinsically normal.

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Let's check it out on the T1 weighted image.

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Intrinsically normal.

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You can see the swelling though

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of the meniscocapsular reflection, ramp lesion.

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This is the blood.

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That's the blood.

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Let's go over to the lateral side.

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Not normal.

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We already said there's a meniscovesicular detachment,

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but what is this?

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What is this?

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That doesn't belong there?

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This is a younger individual, 15 years old.

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You should be seeing very little signal

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in the posterolateral meniscus.

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And if I blow it up for you?

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Let's go all the way into the midline.

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I'm going to make it a little brighter.

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Here's your meniscus.

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I'm going to color your meniscus.

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Almost done.

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And then, I'm going to color

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your wrisberg ligament.

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Now, when I take it away,

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you're going to see the line between the two.

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See the line?

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Right there.

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Now, let's scroll towards the periphery.

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The line is still there.

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There's the ligament.

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Now, it gets a little kooky.

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The line is persisting.

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There's no ligament coming out toward the lateral

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aspect of the knee.

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That line should be gone.

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The fact that that line persists here,

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and here,

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and here,

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and here,

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tells you that you have a complex tear

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emanating from the weakness

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at the meniscofemoral ligament interface

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known as a Wrisberg rip.

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So, in summary of this case,

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pivot shift injury,

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valgus event with high grade ACL,

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hemarthrosis,

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meniscopopliteal fascicle detachment,

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posterolateral,

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lateral meniscus tear,

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Wrisberg rip type complex,

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medial ramp one lesion.

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Multiple bone injuries.