0:00

You're looking at a six-year-old who

0:02

presents with foot pain and some stiffness.

0:07

And you're looking at a T1-weighted

0:09

image on the far left, fat-weighted.

0:11

A proton density image in the center,

0:13

not fat suppressed.

0:15

Looks like a T1-weighted image, but isn't.

0:18

And on the far right, a conventional T2,

0:21

fast spin echo, without fat suppression.

0:25

The patient was actually sent in

0:26

rule out or exclude osteoid osteoma

0:29

because the bone scintigraphy was

0:31

markedly positive in a focal area.

0:34

They didn't give us the bone scintigraphy and

0:36

I'm not going to give it to you because many

0:38

times you're going to be looking at the MR

0:40

alone and my goal is to get you trained in MRI.

0:43

So let's scroll and an osteoid osteoma will

0:47

typically show up as a round nidus and the nidus

0:52

is typically not liquefied.

0:55

So, in other words, if you do a T2, like the one

0:57

on the right, it should never be white like fluid.

1:02

If it's white like fluid, you better

1:04

be worried about a Brodie's abscess.

1:07

Then you may see a rim of sclerosis around it,

1:12

with the nidus in the center, which is not fluid

1:15

like, and that sclerotic rim will be dark, and

1:18

then, in some cases, depending upon where the

1:21

OO or osteoid osteoma is located, you may see

1:25

massive amounts of edema or very little edema.

1:29

Typically, when you're medullary,

1:31

you're going to see more edema.

1:32

When you're juxtacortical, you may

1:34

see less, little, or even no edema.

1:38

So, as we scroll through looking for

1:40

something with that pattern, we don't see it.

1:43

Now, it would have been absolutely

1:45

lovely to have a heavily fat suppressed,

1:48

water-weighted sequence like this one.

1:51

And we have it.

1:53

And we scroll it.

1:54

And we do not see such a

1:56

hyperintense edematous nidus.

1:58

Although, we do see a little bit

2:00

of higher signal right there.

2:02

That's a little bit round.

2:04

And some of you might say, seeing that

2:06

image alone, well, maybe there is.

2:09

But we're not done yet.

2:10

So let's take that away and

2:12

bring back our sagittal T2.

2:14

And keep scrolling.

2:15

Now, where was that spot?

2:18

If I cross-reference, which I won't do now, in the

2:20

interest of time, to that spot, it's right here.

2:24

And we've got ourselves a

2:28

talocalcaneal fibrocartilaginous coalition.

2:30

Now, unlike the standard joint, this particular

2:33

joint has a look that's a bit more serrated.

2:38

Whereas our standard joint

2:39

would be nice and smooth.

2:41

And we would see a thin, smooth,

2:44

homogeneous cartilage line.

2:46

We don't.

2:47

We see the serrated appearance.

2:49

It also sticks out a little too far.

2:52

We're coming out of the talus, yet we

2:56

still see this prominent, jutting into

2:58

the screen, jutting medially, middle

3:02

facet with a cartilaginous interface.

3:06

Now, yes, it could have been a bony bar.

3:08

It could have been a bone connection

3:09

between the talus and the calcaneus.

3:12

But it's not.

3:14

This is one of the two most

3:15

common types of coalitions.

3:18

The other type that is common would be

3:21

a coalition between the anterior process

3:23

of the calcaneus and the navicular, the

3:25

so-called calcaneonavicular coalition.

3:29

We certainly don't have that.

3:31

And we have seen other coalitions, including

3:34

coalitions between the calcaneus and the cuboid.

3:38

And very, very rarely will you see

3:40

a coalition between the talus and

3:42

the navicular in the anterior facet.

3:45

So what are the symptoms of coalition?

3:47

We already said the child had pain and spasm.

3:50

So that should tip you off.

3:52

Children with flat feet, that

3:54

should also potentially, uh, tip

3:56

you off to the, to the diagnosis.

3:59

And individuals that have a stiff foot

4:02

with decreased range of motion should

4:04

tip you off to the potential diagnosis.

4:07

So what's the treatment?

4:08

Well, if it's a bony coalition, then one

4:12

option is to try and release that coalition.

4:16

There are also spacers that are placed

4:18

between the talus and the calcaneus to try and

4:21

produce an arch, a fake arch or a false arch.

4:25

In my personal experience, these spacers

4:28

have not stayed anchored for long

4:30

periods of time, and so this is not one

4:33

of my favorite methods of treatment.

4:35

On the other hand, sometimes when you have a

4:37

fibrocartilaginous coalition where you have

4:40

too much movement between this arthritic

4:43

irregular pseudoarticulation or fake or false

4:47

articulation, you may actually, to improve

4:50

the patient's pain, but not necessarily

4:52

their functionality and range of motion,

4:55

fuse that locus.

4:57

Now in the coronal projection, I

5:00

find this extremely helpful because

5:02

I see the, the facet jutting out.

5:05

And we do see it here, but not as

5:06

well as I'd like because guess what?

5:09

When you look in the side view, look

5:11

at where they produce their coronal.

5:14

That's as far back as they went.

5:16

They didn't go back far enough to see

5:19

the actual body of the coalition because

5:22

they were not expecting the diagnosis.

5:24

Had we gone further back, this area

5:26

right here would start to jut further

5:28

and further and further medially.

5:30

And that would help you reaffirm your diagnosis.

5:34

The axial projection, whoops, let's pull it down.

5:38

The axial projection with a PD fat suppression

5:40

and a T2, does show a little bit of that

5:43

jutting out phenomenon right here, right there.

5:48

And it also shows a little bit of inflammation

5:51

right at the site of the coalition.

5:54

This erosion as part of the inflammation

5:57

masquerading, you can see the erosion

5:59

right here, masquerading potentially as

6:01

a round structure and the diagnosis of

6:04

osteoid osteoma, which was not present.

6:07

This is a talocalcaneal fibrocartilaginous

6:12

coalition in a six year old.