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Okay.

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Welcome to our practical approach to one thing

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and one thing only today, menisci.

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So, I'm starting out with exactly what I said

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I wasn't going to do, a slide.

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You know, this is not meant to be didactic.

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It's meant to be an interactive experience so that

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you really understand how to talk about,

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not talk about menisci.

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But I have to have some,

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just basic framework of anatomy,

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and here it is.

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So I made this simple diagram,

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and on your left is kind of a broader half circle,

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and on your right is sort of a tighter

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C shaped circle.

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The one on the left happens to be

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the medial meniscus.

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Your left.

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The one on your right is the lateral meniscus.

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This part of the meniscus actually attaches down

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into the screen.

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That's called the root ligament.

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We can't see that, but this is the meniscus root.

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Here's the front root.

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There's the back root,

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And then, the rest of this is the anterior horn.

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And we'll keep it simple.

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The front third is the anterior horn.

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The middle third is the body.

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The posterior third is the posterior horn.

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Once again,

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these are the roots attached by ligaments.

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The menisci are also attached out peripherally

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by the capsule.

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Some tighter than others.

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In fact,

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the medial side has a tighter attachment

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than the lateral side.

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That's why it's more prone to

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certain types of meniscocapsular injury.

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And the same rules apply here.

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A third, a third, and a third

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for anterior horn body and posterior horn

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with attachment on the outside.

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Now, on the inside,

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the free edge of the meniscus is not attached.

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It's like the wing tips of a manta ray.

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It's just floating in synovial fluid.

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And sometimes,

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it'll get a little bunched up or squished.

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And when it does that,

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it looks a little funny,

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especially when there's synovium.

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That is the normal phenomenon and pitfall

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known as meniscal flounce.

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And we're going to see it.

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Now, the meniscus is also divided up into thirds,

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an inner third, a middle third,

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and an outer third.

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And in every meniscal tear,

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we want to comment on that,

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because the tears that occur here,

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you should almost never, ever operate on.

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They're all going to heal

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well enough on their own,

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better than they would do if somebody

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manipulated them or cut them out.

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The ones in the middle,

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kind of maybe yes,

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maybe no.

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But usually, not surgical candidates.

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The ones on the inner free edge,

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those are the ones that are more likely

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to require surgical intervention.

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And these areas are also known as the

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red white zone in the middle,

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the red red zone on the outside,

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and the white white zone on the inside,

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in orthopedic parlance.

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Now, this next slide,

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and this will be the last slide before we go into cases,

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demonstrates the meniscus in cross section.

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Now, you might have noticed in the last slide,

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there are some different colors in there,

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and I don't really care about those too much.

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But the bottom line is, within the meniscus,

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there is specialized anatomy that conducts

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synovium from the joint to the outside.

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So, there is a pathway of flow.

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I can draw it for you.

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See if it'll let me.

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There's a pathway of flow that goes this way.

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Notice it goes right along this

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purple and yellow anatomy.

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And that persistent flow along these bands of collagen

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that live inside the meniscus

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represents the normal intraminiscal signal,

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which you now see,

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is not present in the inner third,

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as depicted by this purplish area,

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starts around the middle third,

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depicted by the yellow,

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and then kind of breaks off into two bundles,

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one here and one there.

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Kind of makes like a little fork

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or a couple of bunny ears,

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if you turn it straight upside,

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right side up.

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And those bunny ears are normal,

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they should be relatively faint.

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They should never be equal to or

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brighter than hyaline cartilage.

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They should never go all the way back to the capsule.

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They should never go up and down.

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They should never have complex character.

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They should have exactly what I've drawn here,

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this gently sloping character.

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Now,

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a lot of your colleagues will refer to these signals

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in different ways.

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You'll hear them called contusions.

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You'll hear them called degeneration.

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You'll hear them called myxoid change.

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You'll hear them called cysts.

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And each one of these has an appropriate

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setting where it's to be used.

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But let's give an example.

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You're fresh out of training,

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and you call the signal in the

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meniscus in a 32-year-old,

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otherwise healthy girl that just ran 3 miles,

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meniscal degeneration.

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But the rest of her knee looks fine.

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Why in the world would you use the term degeneration?

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She has no DJD.

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Her meniscus is of normal size.

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She just ran 3 miles.

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It is a silly term to use in that setting.

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Or if I hear degeneration in the 13 year old,

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what 13 year old has a degenerated meniscus?

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Nobody,

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except maybe somebody with a discoid meniscus.

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This is silly stuff.

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This is like saying,

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"Let's give all the banks any of the rules they want."

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That's silly stuff.

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Let's stop doing silly stuff.

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And your job, your primary job,

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is to save the whales.

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Save the menisci.

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The slightest amount of trimming in the meniscus,

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change the knee dynamics forever

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for that person's entire life.

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It is a total game changer.

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So, the worst thing you can do is call

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something that is not there.