0:00

Let's take a look at this 10-year-old

0:02

female who has a "fracture".

0:06

Let's scroll this sagittal projection together.

0:09

And I always put up my sagittals first

0:11

because it's like a lateral radiograph of the

0:12

foot, and that is where my comfort level is.

0:16

I know the anatomy inside and out.

0:19

And as I scroll, I really focus on the

0:23

water-emphasized image, which is the one

0:25

on the right where the bones are black.

0:28

It's like a bone scan.

0:29

I am looking for hotspots, and anytime

0:33

I see a cluster of hotspots at the TMT,

0:37

at the tarsometatarsal junction, doesn't

0:40

even matter where it is, as long as it

0:41

involves multiple bones, I am worried

0:44

about some type of midfoot injury.

0:46

So I'm already there mentally.

0:50

Now I want to decide ligamentous status

0:53

and what kinds of fractures I have.

0:56

The fractures may be completely obvious

0:58

or you may have to resort to very high

1:01

resolution CT to see a lot of these smaller

1:04

fractures, but it's usually not a requirement.

1:08

So if I'm going to evaluate the Lisfranc

1:11

ligament properly, I've got to have

1:12

what's known as Lisfranc views on MRI.

1:15

Yes, there are Lisfranc views.

1:17

And they are not straight orthogonals like this.

1:21

They go down the long axis of the foot so

1:23

that they are parallel to the orientation

1:26

of the tarsometatarsal junction, and

1:29

specifically parallel to C2 and M.

1:35

Alright, let's take our short-axis views,

1:39

which have been performed this way.

1:42

And they're actually, even though they're para-

1:45

aals, they are really long views of the foot.

1:50

They go all the way from the

1:53

metatarsals and phalanges back to the heel.

1:56

So they're running in

1:57

parallel with C2 and M2.

2:00

And in parallel with C1 and M1, remember,

2:04

the foot is divided up into three columns,

2:07

a medial column, C1, M1, a middle

2:11

column for M2, C2, M3, C3.

2:16

And then a lateral column for the outer two.

2:19

We're already suspicious because

2:21

there's a tremendous amount of

2:22

swelling in this 10-year-old's foot.

2:25

And that swelling is centered

2:26

right around this region.

2:28

If you want to put your bullseye

2:29

somewhere, put it right there.

2:32

So now, you're probably all saying

2:34

to yourselves, while watching,

2:36

Okay, there's the Lisfranc ligament.

2:39

Remember the Lisfranc ligament

2:40

has a proper component, which is

2:42

interosseous, smack dab in the middle.

2:45

That's the important one.

2:47

The next most important one is the

2:49

plantar one, which goes from C1 to M2.

2:53

And the least important, but still

2:55

somewhat important, is the dorsal one.

2:58

So the proper is like a sandwich.

2:59

And you're saying, well, I see

3:01

a nice black line there, really?

3:03

You do?

3:04

Well, what's the signal of blood?

3:06

Black.

3:07

What's the signal of a ligament?

3:09

Black.

3:10

What is the signal of hemocytarin?

3:13

Black.

3:13

What's the signal of fibrous tissue?

3:15

Black.

3:17

You're not going to see.

3:19

A Lisfranc ligament injury properly without

3:22

high resolution and a T1-weighted image

3:27

or a 3D thin section gradient echo image.

3:31

And if you turn your attention very carefully

3:34

to the T1-weighted image, do you actually

3:37

see a line that is running from the base

3:40

of the second, which by the way has a

3:42

fracture in it, to the C1 first cuneiform?

3:47

No, you don't.

3:48

You don't.

3:49

There's a defect right there.

3:50

I'm gonna make it even bigger.

3:53

Let's make it bigger.

3:54

Oh, there's a defect there, isn't there?

3:56

Ligament?

3:57

Nothing.

3:58

Let's make it bigger on the right-hand side.

4:03

That is a weenie little ligament right there.

4:05

In fact, that's not a ligament.

4:06

That's just a little bit of blood.

4:08

There is one end.

4:09

There is the other end of the

4:11

torn, proper, Lisfranc ligament.

4:15

Now, we said we were going to break these up into

4:18

different stages according to the Kenyon Kuss

4:22

classification described in 1909 when I was born.

4:26

But in this case, that classification is isolated.

4:30

Homolateral or Divergent doesn't really apply.

4:34

Because the metatarsal bones aren't

4:35

really moved in any direction.

4:38

And you can go back and look at

4:39

that classification vignette.

4:42

So we might have to resort to a

4:43

different classification system.

4:46

And we'll do that separately in a moment.

4:49

But let's check out the rest of the ligaments.

4:51

Let's do a little bit of scrolling here.

4:54

Let's scroll dorsally, and let's

4:59

scroll to the plantar surface.

5:01

Now on the plantar surface, and I know I'm

5:03

very magnified here, but that's my intent.

5:06

Let's go to the plantar surface.

5:08

That is the stub of the plantar

5:11

ligament that goes from C1 to M2.

5:16

That's it right there.

5:17

It doesn't go to M2 because it's ruptured.

5:21

These are plantar ligaments.

5:24

Here's another one.

5:25

That one looks a little bit better.

5:26

This one goes from C1 to M3.

5:29

Except that, it stops right there.

5:32

How do you know?

5:33

Look at the T1.

5:34

It looks like a squiggle, wiggle, it's too

5:37

gray, it's not black, it's not straight.

5:40

It never reaches the base of the fractured M3.

5:44

Never gets there.

5:45

That's as far as it ever goes, right there.

5:47

That's the end of the squiggle.

5:50

So, the C1 M3 ligament, torn.

5:53

The C1 M2 plantar ligament, torn.

5:56

The proper Lisfranc ligament torn.

6:00

And in a separate vignette, I'd like to take

6:02

this case and do some classification with you.

6:05

So if you have time, stay tuned.