0:00

Continuing on with our discussion on

0:02

osteochondral lesions, it just would not be

0:05

complete without talking about the most classic

0:08

form of osteochondral lesion, which happens

0:10

around the knee in the pediatric population.

0:12

Most specifically, it happens at the lateral

0:15

aspect of the medial femoral condyle.

0:19

So, let's find the fibula; that's lateral.

0:22

So we know this is the medial femoral condyle,

0:24

and if you notice, this is at the lateral

0:26

aspect of the medial femoral condyle.

0:29

So, you know the term LAME, L-A-M-E, which

0:34

stands for Lateral Aspect Medial; you

0:38

know, E is for epicondyle, but medial condyle.

0:42

So, this is where you have the most

0:44

common location of an osteochondral

0:46

lesion in the pediatric population.

0:49

When we talk about osteochondral

0:50

lesions, we have to characterize them.

0:53

It's not just enough that

0:55

we say that it's there.

0:56

We have to talk about the size

0:58

of the osteochondral lesion.

0:58

So, you have to measure the osteochondral lesion.

1:00

So, let's go ahead and do that.

1:02

On the coronal view, if I go from here

1:04

to here, it's about 2 centimeters.

1:09

On the sagittal projection, if I go

1:11

from here to here, it's also about 1.4 centimeters.

1:15

4 centimeters.

1:17

So we've given the sizes.

1:18

Now we have to talk about its characteristics.

1:21

This image on your left is a sagittal

1:24

fat-suppressed fluid-sensitive sequence.

1:26

We notice, I'm going to get rid of this line

1:28

just so we can see things a little easier.

1:31

You notice there's a rim of bright signal,

1:34

a rim of low signal, and some

1:36

more edema underneath that.

1:38

We can also talk about the

1:39

integrity of the cartilage.

1:40

You know, there's a little bit of high

1:42

signal on the undersurface of the cartilage.

1:45

Okay.

1:45

And this rim of signal here is not quite

1:49

as bright as the fluid in the joint.

1:52

So that also tells us about

1:53

instability or stability.

1:55

If we have fluid signal around this

1:58

area of osteochondral lesion, that's

2:00

as bright as the fluid in the joint.

2:02

Okay.

2:02

Then that indicates an unstable lesion.

2:05

If it's just merely edematous

2:07

like this, it's still stable.

2:10

The thing to realize is, in the

2:12

adolescent period,

2:16

osteochondral lesions are a lot more

2:18

resilient than in the adult population.

2:20

In the adult population, a rim of edema

2:23

alone would qualify it as an unstable lesion.

2:26

But in the pediatric population, you

2:28

really need fluid signal to be unstable.

2:30

So this is not unstable.

2:32

Right, by that criterion.

2:34

We also look to see if there are any cystic

2:36

changes around the osteochondral lesions.

2:38

This one does not have any cystic changes.

2:40

If an individual cyst is more than five

2:43

millimeters, or there are multiple

2:45

cysts, then that also means it's unstable.

2:48

And finally, we look at the

2:49

integrity of the cartilage.

2:50

If the cartilage has rifts or tears

2:53

in it, that indicates instability.

2:55

So, looking at all those findings, I would say

2:58

that this is a stable osteochondral lesion.

3:01

They will go in and maybe fix it

3:03

by drilling, or they may just rest

3:06

the knee to see if it gets better.

3:08

In the pediatric population, oftentimes

3:10

you'll have areas of abnormal or what

3:13

looks like abnormal fragmentation at the

3:16

posterior aspect of the femoral condyle.

3:19

And that should not be confused

3:21

with an osteochondral lesion.

3:23

First, those lesions occur on non

3:26

weight-bearing surfaces, like over here.

3:29

And second, there's no associated edema.

3:31

So don't confuse something that happens

3:33

back here with something that happens

3:35

down here for an osteochondral lesion.

3:38

And typically, these lesions here happen in

3:42

a younger population, maybe 4, 5, 6, 7, or 8.

3:46

This over here typically

3:47

happens in an older population.