0:00

This is a 28-year-old male football player

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who felt a pop while making a cut.

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He's got pain and marked swelling.

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The axial projection, seen here at low field,

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which does just fine in the knee.

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And the contrast resolution at low field is

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probably better than it is at high field.

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The spatial resolution at high field

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is better than it is at low field.

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We've got great contrast resolution here.

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And we see a blood fluid level,

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which means is we probably got fractures.

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Can we find them? We sure can.

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There's one in the back right there.

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That is not a normal appearance of the

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posterolateral tibia. That is.

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Might we have other fractures?

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We might. There might be one in the femur.

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We'll corroborate that in another projection,

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and you could ignore for now,

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this area of chondromalacia,

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in the medial patellar facet.

0:50

Let's pull down our sagittal T1 and

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put it astride our coronal.

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So on either sides of our fat suppressed,

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water weighted coronal are a T1 and a water

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weighted, fat suppressed sagittal. All right,

1:04

let's scroll these together.

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And we have established a depressed,

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broad osteochondral fracture of the femoral

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terminal sulcus of the lateral femur.

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That means we've had a pivot shift injury.

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And now it's time to look for

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the non kissing injuries.

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Fractures or contusions that are going to be seen

1:26

as the femur is driven backwards onto the

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tibia or the tibia moves forward.

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So this will come in contact with this during

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the pivot shift event, and indeed, it has.

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Resulting in a fracture.

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A fracture with a fracture fragment seen on T1

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and the fracture corroborated in the coronal

1:46

projection. So what does this tell us?

1:50

It tells us that the injury has been pretty

1:52

violent. There's a much smaller bone injury.

1:55

Postromedially,

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there's a posteromedial capsuler corner injury

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with swelling of the capsuler interface.

2:01

That'll be a story for another vignette,

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but let's go back over to the lateral side,

2:07

and we'll pass by the pcl,

2:09

or posterior cruciate ligament. It's intact.

2:12

We'll pass by the ACL.

2:14

It is not intact.

2:16

It is just a bag of blood and floating fibers.

2:20

Where's the cut? Right there.

2:23

So not unexpected with this family of

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bone injuries. The ACl is gone.

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Let's go to the lateral corner.

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And in the lateral corner,

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we are concerned with the fibular collateral

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ligament, which is part of the LCl complex.

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We've already established that that's intact.

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So now we're interested in the popliteus tendon.

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We can establish in the coronal projection.

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The papillatius tendon is intact.

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And in the corner we are especially interested

2:54

in the pop fib ligament.

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So here is the popliteus tendon.

2:59

And that is the blunted,

3:02

non attached pop fib ligament.

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So that should be attached to the tip of

3:07

the fibula. Just medial to the arcuate.

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Let's look at the arcuate area.

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Which is right behind the papaltius tendon.

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It's this area right here.

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This is all arcuate. This is capsule.

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This is the oblique papillate ligament

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and capsule, which, by the way,

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are injured and a little swollen.

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But right in front of it is the arcuate space.

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There should be linear fibers running up and down.

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And they're not.

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They're gone.

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Let's look coronally and see if we can

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identify the arcuate. And we can.

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It comes right off the tip of the fibula.

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And there it is. And there it stops right there.

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So as the arcuate comes up, it splits.

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It'll come up off the tip of

3:53

the fibula right there.

3:55

And then it'll have a vertical limb in the

3:58

back and an oblique limb in the back.

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Neither of which we see because the

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arcuate is blunted right there.

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So we can firmly establish that the pop fib

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ligament is torn. The arcuate is torn.

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Let's check out the lateral meniscus and its

4:14

attachments. It has an upper attachment.

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And then there should be a lower attachment

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to the popliteus tendon.

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And that is blunted. There's too much space here.

4:26

It almost looks like it's floating there.

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It's clearly blunted. More pointed.

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Blunted. Pointed. Blunted.

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So the inver attachment of the lateral meniscus.

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And the meniscocapsular junction is injured.

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So we've got some major structures in the

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posterolateral corner that are dinged.

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We have torn the pop fib ligament.

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We have torn the arcuate.

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We have partially torn the meniscocapsular

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attachment.

4:58

Now, in my conclusion,

5:00

that would all go in there along with the ACL

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transection and the mechanism of injury.

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Namely pivot shift.

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Mechanism of injury with ACL transsection,

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hemarthrosis and posterolateral corner injury.

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That includes a, b and c.

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Now I would put into the body of the report

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the posteromedial corner injury.

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Because that's of lower grade character.

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And then I would describe in the conclusion

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the status of the meniscae.

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And they are pretty well preserved in this case,

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except for the posteromedial meniscocapsular

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junction where there is a sprain.

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And I would add that into my conclusion and say

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the meniscai are otherwise unremarkable.

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Nasty posterolateral corner injury at low field.