0:00

Okay, this is a young teenager with pain, possible

0:05

osteochondral defect, possible bone injury,

0:08

possible stress fracture, rule out life itself.

0:12

We have a sagittal T1, a T2,

0:17

and a fat-suppressed PD.

0:20

Let's start scrolling, and I'm going to

0:24

focus primarily on the sagittal, which

0:26

which is my favorite foot and ankle projection.

0:29

And I may pull down one or two

0:31

other projections near to the end.

0:34

And I want you to make some medical, emotional,

0:38

and mental decisions about what types of

0:42

bone injuries or abnormalities you would

0:45

consider in a case like this in a juvenile.

0:50

Well, first, I want to point out to you

0:52

these speckled foci of low signal on T1

0:57

that are scattered throughout the foot, many

1:00

of which are not coalescent, like these.

1:04

They're very delicate.

1:06

They look like somebody

1:07

kind of spray painted them.

1:08

Very gently and focally, these little

1:11

dots across the lower extremity.

1:15

That is a very common scenario in

1:16

juveniles, especially under the age

1:18

of 10, which this person is not.

1:21

And it results from increased bone turnover,

1:24

increased bone metabolism, and hyperemia,

1:27

and you will see this in what I call lower

1:29

extremity abusers, of which all juveniles

1:32

under the age of 10, maybe 12, are guilty.

1:37

That in itself may cause some discomfort,

1:40

but usually does not prompt the

1:42

patient to come in for pain.

1:44

And when I say usually, yes, I do have patients

1:46

that come in, and that's the only finding.

1:48

Somebody looks at it and calls

1:50

it a stress fracture, or RSD.

1:53

That is not a usual manifestation of RSD, also

1:58

known as Complex Regional Pain Syndrome Type 1.

2:03

So, speckling in itself is not an alarm bell.

2:08

And we do have quite a bit of speckling.

2:11

Now let's skip over the T2 for a moment,

2:13

because it is not a marrow-sensitive sequence.

2:16

It's a modifier.

2:18

It helps you decide on age and severity

2:21

and a few other complementary things.

2:25

And let's go over to our water-weighted image.

2:27

And there are some areas that are

2:29

very coalescent, especially in the

2:31

upper calcaneus, where it's brighter.

2:35

There's some linearity to it.

2:36

Let's blow it up, like right here.

2:40

There's linearity along the posterosuperior

2:43

aspect of the calcaneus with more confluent edema.

2:49

What shall we call this?

2:51

A microtrabecular stress injury.

2:53

Now what would be a flat-out stress fracture?

2:57

It'd be a little thicker, it'd be a little

2:58

better defined, and it would have an appearance

3:01

in the bone that looks something like this.

3:03

Almost like atrial fibrillation.

3:05

I may have to do it a little

3:07

bit bigger for you to see.

3:08

Yeah, there we go.

3:09

And I'm going to show you some

3:10

of these in other vignettes.

3:13

So I'm not quite ready to give him a full,

3:15

flat-out, full-blown stress fracture, but I

3:17

am willing to give him a microtrabecular stress

3:20

injury and other areas that are more confluent

3:24

with lesser degrees of stress phenomena.

3:27

In other words, bone marrow edema.

3:30

Now, do notice that the bone marrow edema

3:34

in these other loci, like the talus and the

3:37

navicular and the cuneiforms, is central.

3:42

And the central teaching point of a case like

3:45

this is that in RSD, Complex Regional Pain

3:50

Syndrome Type 1, the edema is subcortical.

3:55

It's in the wrong place for that diagnosis,

3:58

which you should have at least considered.

4:02

So RSD is not going to be a strong

4:05

choice for us radiographically.

4:09

What are we going to do to explain those areas?

4:13

Overuse phenomenon.

4:15

Likely symptomatic, not just

4:17

speckled, but more coalescent.

4:19

So what should we call those?

4:21

Microtrabecular intramedullary bone injuries.

4:24

I'm calling this one a microtrabecular

4:27

overuse fracture, not a full-blown

4:30

stress fracture, but microtrabecular.

4:32

I'm calling these overuse

4:34

microtrabecular injuries.

4:36

Now because this is a young person,

4:38

because every bone is affected, I'm

4:42

a little concerned about possibly an

4:44

underlying metabolic or genetic disorder.

4:47

And the one genetic disorder that I might

4:49

have in the back of my mind, especially if I

4:52

start to see more real stress fractures evolve

4:55

on subsequent imaging, or as I follow this

4:58

patient, is osteogenesis imperfecta tarda.

5:02

This patient doesn't have it, but

5:04

should absolutely be screened for

5:06

this if this process is necessary.

5:11

Let's keep going, shall we, because one of the

5:13

questions asked by the clinician, is there an OCD?

5:18

Let's answer that question,

5:19

and the answer is, absolutely.

5:22

An osteochondral defect, a defect in the

5:26

talar dome, and that's why, as promised,

5:29

I have to call up another projection.

5:31

Another water-weighted projection, and

5:33

here it is, in the coronal plane, and

5:37

there is an osteochondral defect in the

5:40

supramedial aspect of the talar dome.

5:42

The talus was swelling around it.

5:45

Now just a word about osteochondral defects.

5:47

I'll call up the axial to see

5:48

if we can see it as well here.

5:51

There it is.

5:52

I'm going to blow it up and

5:53

make it a little lighter.

5:55

And I'll be brief with this.

5:58

There's a very important teaching point

6:00

here that's separate and distinct from all

6:02

the other things that are causing edema

6:05

in this patient, this juvenile patient.

6:08

And that is the character

6:09

of the osteochondral defect.

6:12

Yes, you can all look up that

6:14

you can measure the defect.

6:15

You can put a ruler on it.

6:17

You can give it a depth, a length, and a width.

6:20

You should look at whether

6:21

there's any loose bodies.

6:22

You should look at the chondral surface to see

6:25

if it's blistered or swollen or there's a defect.

6:28

There's one other really important teaching point.

6:31

And that's not why I'm showing the

6:33

case, but I'll throw it in here since

6:35

we are on an osteochondral defect.

6:38

And that is, is the defect shouldered?

6:42

What I mean by that is, let's

6:44

take the talar dome right here.

6:46

It's a talar dome.

6:49

If my defect is here and I have some

6:53

decent bone to the side of it, like here.

6:58

That means it's shouldered.

7:00

However, if my defect goes all the way up

7:04

to the free edge, out here, and there's

7:07

no shell of bone covering it, now you

7:10

cannot put a bone plug in here or a

7:12

graft that's gonna stay in and be stable.

7:16

So it's important, you tell the clinician whether

7:19

that OCD, which is right here, there it is, I've

7:22

colored it in, is shouldered or unshouldered.

7:26

In this case, it does go up to the free edge,

7:28

even though I don't have the preferred coronal

7:31

T1-weighted image to show you, because that

7:34

is not the main reason I am showing the case.

7:36

So in summary, we've got a lower extremity

7:40

abuser with some speckled areas of high

7:42

turnover, hypervascularity, increased metabolism

7:47

in the skeleton, which we see a lot as a non

7:51

contentious form of lower extremity overuse.

7:55

We've got a microtrabecular fracture in the

7:58

posterosuperior calcaneus, which should heal

8:03

on its own within about two to three weeks.

8:06

We do not have a full blown stress fracture,

8:09

which you'll see a little bit later on.

8:12

We have areas of marrow edema, so-called medullary

8:16

stress or overuse phenomenon in other bones.

8:19

We should make sure the patient doesn't

8:21

have underlying, uh, metabolic bone disease

8:24

or genetic bone disease like OI, imperfecta

8:28

tarda, and the patient does have a clear-cut

8:33

osteochondral defect with a length, with a

8:36

width, with a depth that is non-shouldered

8:41

and goes all the way out to the free cortical

8:43

surface of the supramedial talar dome.