0:00

Let's take this 52-year-old female with

0:02

a fall and a "inversion injury"

0:06

and let's scroll the sagittals.

0:10

There's the sagittal, water-weighted,

0:13

fat-suppressed image, and there is a bevy

0:17

of hyperintensity in the midfoot area.

0:20

Oh, it's so complex-looking.

0:22

It'd be hard to pick out

0:23

what's what and who's who here.

0:25

But there's soft tissue swelling, there's marrow

0:27

edema, and the bones, if you look at the T1

0:30

weighted image, which is a little more morphologic

0:32

and a little easier on the eye, you'll notice

0:36

that the bones are aligned kind of strangely.

0:39

In fact, some of the bones look like

0:40

they're rising up a little bit dorsally.

0:43

The fact that the abnormality is

0:45

epicentered at the tarsometatarsal

0:47

junction, you have malalignment; you should

0:50

automatically start thinking about midfoot

0:53

subluxation or dislocation syndrome.

0:56

Let's just go back to the mechanism again.

0:58

When you are on your foot in some type of ball

1:01

field, it can be soccer, European football,

1:04

American football, whatever, and you're pushing

1:06

off, your foot is anchored in the ground.

1:10

Now, with this injury, it's more frequently

1:12

abducted, and you're kind of leaning a little

1:14

bit more off the inside of your foot, but

1:18

in my experience, it really doesn't matter

1:19

whether you're leaning inside or outside, and

1:21

it doesn't matter whether the foot is turned in

1:23

or out, but if there's pressure on that foot.

1:27

And then you have a rotational

1:29

force placed against it.

1:30

That's what can lead to this injury.

1:32

Another mechanism is when you have a planted

1:35

foot, and someone comes along the back of your

1:37

heel and slams your heel down as you're trying

1:40

to push off that specific position.

1:44

So those are the mechanisms that can

1:46

give you the finding that you're injured.

1:48

You're about to see.

1:49

So, now, my suggestion is to turn to the long

1:54

axis projection, which is actually an axial, and

1:57

that axial is obtained this way, along the long

2:01

axis of the foot, but technically, it's an axial.

2:05

So, it'll look somewhat coronal to

2:07

you, and as we scroll, let's start

2:11

scrolling the water-weighted image first.

2:15

And you immediately see that there is extensive

2:19

edema throughout, virtually every metatarsal

2:23

base, M1, M2, there's a fracture, M3,

2:28

there is a fracture, M4 and M5 spared.

2:33

There's also an abnormality of the cuboid

2:37

and virtually every CU offor C3, C2; even

2:41

the medial aspect of C1 is affected.

2:44

I mean, there's no way with

2:45

this pattern of bone injury

2:47

that the Lisfranc ligament can survive.

2:50

Now let's go back and talk about

2:52

the Lisfranc ligament again.

2:54

And we've talked about it in other vignettes.

2:58

And I'd like to go right to the

2:59

Lisfranc area, which is here.

3:02

And on the short-axis T1,

3:03

it's gonna be right here.

3:06

Now just as a matter of teaching, there are

3:09

gonna be dorsal elements of the Lisfranc ligament.

3:12

And it's called the dorsal C1M2 ligament.

3:17

And then there's going to be a plantar component.

3:22

And there'll be plantar components that

3:23

go from C1 to M2, the second metatarsal,

3:28

and to M3, the third metatarsal.

3:30

So we would call these the dorsal and

3:33

plantar portions of the Lisfranc complex.

3:37

The proper ligament is right smack in the middle,

3:40

and no, it doesn't go all the way from here to

3:42

here; it's just kind of right in the center.

3:45

And it's pretty strong, it's pretty

3:47

stubby. And the dorsal one is also pretty

3:50

stubby, but definitely not as strong.

3:54

So, now I'd like to put back my long

3:56

axis view, and have you look and

3:59

search for the Lisfranc ligament.

4:02

And the proper Lisfranc ligament should be

4:05

right smack dab in the interosseous space,

4:08

between the base of the second and C1.

4:11

So you should see both bones, at the same

4:13

time; you shouldn't be too plantar, you

4:16

shouldn't be too dorsal, and we're not.

4:18

And where's the Lisfranc ligament?

4:20

It's gone.

4:21

There's no linear oblique

4:23

hypointensity going from C1 to M2.

4:26

It's just bunk and gunk and blood.

4:30

Over here on the water-weighted image, same thing.

4:32

There is nothing there, and you

4:34

see a discrete fracture line.

4:37

Okay, we're not done yet.

4:39

We said there are three components.

4:41

We've already established that the

4:42

proper ligament. That's a very bad sign.

4:46

Let's go dorsally for a moment.

4:49

And this is the dorsal direction.

4:51

This is the dorsal direction.

4:53

And that stump is the dorsal

4:57

portion of the Lisfranc complex.

4:59

It doesn't make it over to the second.

5:01

In fact, I'll blow it up a little bit

5:02

more, just to make it a little easier

5:04

on your eye, now that you're getting a

5:05

little more familiar with the anatomy.

5:08

There's the stump.

5:10

Well, if the dorsal's torn, we might as

5:13

well check on the plantar components.

5:15

Very much.

5:15

So we're gonna, now we're out of the second,

5:17

here's the second, now we're below the second.

5:22

And let's see what we find.

5:23

When we get below the second,

5:25

we see the C1M3 ligament.

5:30

And you really don't see

5:31

much of a ligament at all.

5:33

These are matching images.

5:35

There's the ligament, it just kind of fades away.

5:37

It, it in no way makes it over

5:39

to the third metatarsal base.

5:42

There's some floppy portions

5:43

of the ligament right here.

5:44

It should be a nice, straight,

5:46

rigid-looking structure.

5:49

So, C1M3 is torn, and there

5:52

is C1M2 right next to it.

5:55

It is torn.

5:56

It doesn't make it over to the second at all.

5:58

Let's find the second.

5:59

Let's go to the second metatarsal.

6:01

Here's the second metatarsal right there.

6:03

That's the free edge of it.

6:05

I think it might be easier to see here on the T1.

6:08

Here's the second metatarsal with a big fracture.

6:11

And here is the stump or base of, let me go to the

6:17

plantar aspect. The stump or base of C1M2?

6:23

I wish they would scroll together, but they don't.

6:26

And the reason it's so gray

6:27

looking is it's emus and bloody.

6:30

So C1, M2 as a sturdy-looking

6:33

structure and C1M3.

6:35

Again, not making it over in any

6:38

way to the base of the third.

6:42

So in this case, now I'd like to turn

6:44

our attention to how we migrate it.

6:47

And so there's a companion vignette to this,

6:49

if you have the time, you can turn this one

6:52

off and come back to the companion vignette.

6:54

But this is gonna be a nasty,

6:58

type of Lisfranc injury.

7:00

And we're gonna give you two basic grading

7:02

systems to work from in another vignette.

7:05

So please join us if you have the time.