0:00

So with that, um, we'll move on, uh, to the next case.

0:05

Uh, this is case two, a 3-year-old gentleman

0:07

who fell off a roof

0:09

and his injury was actually two months prior, uh, to the MRI

0:13

and, uh, he probably suffered a hyperextension injury based

0:16

on the description of his injury.

0:20

So here's the initial plain films, nothing too remarkable.

0:26

Maybe you could insinuate that there's a little bit

0:30

of widening the lateral joint space compared

0:32

to the medial joint space.

0:34

Now, in of itself, this not really specific

0:36

for a lateral supporting structure injury.

0:39

Sometimes you see lateral joint space whining in patients

0:42

with discoid menisci.

0:44

As we move to the lateral view, we have high suspicion

0:47

that there's some sort of, um, osteochondral injury

0:50

of the joint as evidenced by the presence

0:52

of a lipo orthosis.

0:54

And if we can maybe hallucinate on the lateral view,

0:58

maybe a bone fragment above the fibula.

1:02

Now if I give you the, um, corresponding tibia radiographs,

1:06

tibula, fibula, radiographs,

1:08

you can better see this avulsion of the fibular syl

1:11

or the tip, the superior tip of the proximal fibula.

1:15

This is obviously much better seen

1:20

on ct, this fibular syl avulsion fracture.

1:24

And given the mechanism

1:25

of injury since he had a hyperextension injury,

1:28

it's not too surprising

1:29

that he has an impaction fracture along the anterior aspects

1:33

of the proximal tibia with depression

1:35

of the lateral tibial plateau.

1:37

But one thing I want to, uh, sort of emphasize,

1:40

I know this is an MRI course,

1:42

but once you've read enough MRI,

1:45

you can sometimes see injuries to other

1:48

soft tissue structures on your CT examination.

1:52

For example, if we follow this structure here,

1:55

this is the approximate course

1:57

of the fibular collateral ligand,

1:59

and you notice it's sort of redundant

2:01

and kind of takes this tail, uh, bin and extends superiorly

2:06

and it's just kind of floating there in the breeze.

2:08

And we'll see this on the subsequent MRI,

2:09

which I'll now share with you.

2:11

So we'll kind of go straight to, uh, where the money is. Dr.

2:15

Resnick talked about how sometimes the meniscus can float

2:18

away from the site of injury.

2:20

So we can see that where we'd expect to.

2:22

The tibial arm of the anterolateral ligament is

2:25

basically pulled off.

2:26

We don't see any visible fibers

2:28

and that meniscus is floating superiorly away from the

2:31

tibia, the fibular collateral ligament.

2:34

Very hard to see, but it's this structure.

2:36

So basically what we saw on the CT hold off completely off

2:40

the fibula, the papa atilla tendon, similar to

2:44

that last case, well it isn't, um,

2:47

it wasn't separated substantially

2:49

from the femoral attachment.

2:50

It is a vol off of there and this was shown at surgery.

2:54

And finally, the biceps femoral.

2:56

As we move more posteriorly, we can see the tendon

2:59

Forming and nothing attaching to the lateral aspect

3:02

of the fibula where we expect to see it.

3:04

Now this is why if you don't have plain films

3:07

or ct, it can be hard to identify

3:10

that fibular styloid avulsion fracture,

3:12

especially if you're not looking for it.

3:14

Here we can see the lateral inferior ululate vessels,

3:18

but basically all these small poster lateral corner

3:20

structures, the popeil fibrillar ligament, were expect

3:24

to see the fabelo fibrillar NARAL ligaments.

3:26

There's a lot of edema and disruption of these structures.

3:29

In addition to the bo uh, the styloid avulsion fracture,

3:36

um, this patient also suffered a complete tear

3:39

of the PCL near its femoral attachment, and fortunately,

3:42

and this was shown at arthroscopy,

3:44

his ACL was fairly intact.

3:46

Although I would argue here on this MRI there is a little

3:49

bit of edema, so maybe at least to some degree,

3:52

some ligament to sprain.

3:53

But again, at arthroscopy, um, this was found to be intact.

3:58

Now, i i we remiss without mentioning Dr.

4:02

Ra Resnick's favorite coronal image at the posterior aspect

4:06

of the knee and all this,

4:08

this doesn't have a lot to do with this case.

4:10

You can see that this patient does indeed have a posterior

4:13

root ligament, avulsion of the medial meniscus.

4:16

And this, uh, was repaired.

4:18

So in terms of follow-up, uh, this patient did have this,

4:22

uh, posterior medial, uh, meniscus root ligament tear.

4:25

And uh, this was repaired at the time of surgery.