0:00

Okay, welcome to everybody. Um,

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I'm gonna start out with the first case today and, um,

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it is an 11 year old. He's a male,

0:13

complains of medial pain in the right knee,

0:18

and, um, he's got no known injury,

0:22

as some of you may be noticing that, uh,

0:24

this image on the left is actually a left knee and there is

0:29

also a right knee. So we have both knees available to us.

0:33

And I have two Coronas,

0:35

two paired coronals for you that show a similar finding.

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Just to make it a little easier. Um,

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I might move this one over to the opposite side and then move this one

0:49

over here so it's a little more intuitive. So this is right, this is left.

0:55

And let's do a little scrolling in the coronal objection.

1:01

Now,

1:01

when I look at a pediatric case and we see well over a hundred pediatric MSK

1:06

cases a day in our practice, um,

1:09

one of the first things I do besides look at the history is I try and look at

1:14

the growth plate and decide, you know, is it,

1:17

is the growth played appropriate for the patient's age? Is it open or closed?

1:22

That's very relevant, not only in terms of the diagnosis,

1:25

but in terms of the prognosis of the abnormality.

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Many abnormalities do better when they present in a younger age group.

1:34

Your,

1:34

your decision as to the severity of an abnormality will

1:39

also be based in many cases on the patient's age.

1:44

And as I scroll back and forth on each of these,

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and I am focusing for now on the Corona projection using two

1:52

symmetrical proton density fat suppression images,

1:56

some of you might have noticed that

2:01

the condos don't really kind of equal each other.

2:04

So let's start out with our first polling question because I,

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I think I've given you the salient finding in the, in the salient projection.

2:12

So let's go with the first polling question and put that up.

2:17

Well, while you're doing that, I'll show some other

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Projections. Here's the left side, a T2 weighted image,

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and here's the left side, a T1 weighted image. Let's go to the area of interest,

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which is right here,

2:37

and let's pull the T1 weighted image from the opposite side.

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Take a look at that. It's even broader.

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And now let's look at the water weighted images from both sides as well.

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There's the water weighted image from the right side and the sagittal

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projection, and here's the water weighted image from the,

2:58

the left side in the sagittal projection.

3:06

So rather than wait for the question, let me,

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let me ask you all to self-reflect,

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and I'm gonna put the Corona images back up from both sides.

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I'm make it so it's a little intuitive for you.

3:26

So I got the fibular on the right here.

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This is the right side fibula on the left, left side.

3:32

So do you think that these lesions are stable or unstable?

3:38

I think that's the first question that you should answer because the diagnosis

3:42

should be pretty obvious to you.

3:45

There is an osteochondral lesion involving the lateral

3:50

aspect of the medial femoral conal on both sides, an 11 year old.

3:54

So that's a plain radiographic diagnosis. And let's,

3:58

let's put up our, our question now and see if it's ready. Let's give it a shot.

4:04

All right. Which of the following is true regarding these two knees?

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Now, I'm, I'm not here to be easy on you either.

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Some of these questions will be a little tricky. Some will be easy. A,

4:15

the patient has bilateral osteo andr, decans B,

4:20

the patient has bilateral femoral dysplasia. C,

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one of the A osteocondral defects is unstable and the other is stable D.

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The lateral aspect of medial femoral condi is a typical location. E,

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all of the above. See how you answer this one?

4:41

I'm not allowed to vote, but you are.

4:45

I've already given you clues to the correct answer on this one.

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Let's see what our panel of participants said.

4:57

So most of you said all of the above, which is the correct answer. Yes,

5:02

the patient does have bilateral osteochondritis decans, but yes,

5:06

they also have bilateral femoral dysplasia.

5:10

And I'll show that to you in a moment.

5:12

One of the osteocondral defects is unstable and the other is stable.

5:17

Co lateral aspect of medial femoral condal is the typical location.

5:22

So let's talk about the dysplasia.

5:26

Look at how tall it's taller rather than wide on both

5:31

sides. In fact, most cases of osteochondritis decans, if not all,

5:36

are related to a friction delamination of the

5:40

subarticular blood supply due to repetitive mechanical trauma

5:46

from a dysplasia.

5:48

That's true in any joint where you see Oticon decans.

5:52

I also like the four thirds rule.

5:54

I'd like the lateral femoral con to be no more,

5:57

more than four to three on the ratio between the lateral

6:01

condi and the medial condi. In terms of transverse dimension,

6:05

you can see this one's tall and narrow. This one's short and fat. In fact,

6:09

this one's taller and proximal to distal extent and

6:14

reaches more distally than the lateral femoral conal itself.

6:18

So there's undue force being applied to the medial femoral canes

6:23

on both sides from the simple act of weightbearing.

6:26

So indeed there is bilateral femoral dysplasia.

6:30

A fact that perhaps in the past you might have overlooked

6:35

the lateral aspect of medial femoral condal is the most common location.

6:38

But what's the second most common location?

6:42

I've not posited that to you as a question, but I'm asking you to ask yourself.

6:47

And the answer is the a**l lateral femoral troia,

6:52

which in days gone by of plain radiography, was thought to be a rare location.

6:57

In fact, it's not rare at all.

6:59

It is by far the second most common location of osteochondritis decans after

7:04

this one.

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Now another question that's posited to you is stable versus unstable.

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There is some debate minor,

7:14

but some debate about how to approach stability in children.

7:18

It is said that cysts greater than five millimeters in size are a sign of

7:24

instability.

7:25

I would suggest to you that this sign by itself is a sign of micro

7:30

instability,

7:31

but not necessarily macro instability because I've seen many children

7:36

with open growth plates that have cysts,

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small cysts only even those that approach or exceed five millimeters in size,

7:44

as long as they don't have fluid signal between the lesion and the bone,

7:48

they have the potentially heal. Now,

7:51

the ones that are more likely to heal are the ones that are further and further

7:55

away from the weightbearing portion of the condo.

7:59

So when they're in the antra lateral trochlear ridge of the femur

8:02

non-weightbearing, they heal 95 plus percent of the time.

8:06

So we treat those uber conservatively. Now, if we look at these two,

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look at the fluid like signal confluent,

8:14

very bright and through and through the cortex all the way to the knee

8:19

notch. Much different looking when you really drill into it than this other one,

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which has high signal intensity.

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Not nearly as many cystic foci doesn't have that free edge

8:31

communication and doesn't have that smooth,

8:36

well-defined confluence signal intensity with cortex on either side.

8:42

So those are the criteria I use for stability in a child.

8:46

I use cysts as a secondary sign.

8:49

Some of my colleagues use it as a primary sign. In adults,

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I also use it as a secondary sign. The greater the number assists,

8:57

the greater the size,

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the more likely the patient is to have severe micro or macro instability.

9:04

I use fluid like signal, not edema, but fluid signal.

9:08

I use the morphologic sharpness of the cortical edges and the lack of bridging

9:13

thereof as another sign of instability.

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And then there are secondary signs such as a joint effusion.

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And if there's displaced chondro or chondro osseous bodies,

9:25

then the diagnosis is made easy.

9:28

So this is an example of bilateral osteochondritis decans.

9:34

The patient does have some subchondral edema that's worse on the right than

9:39

on the left. The patient has cyst from instability, more of them,

9:44

and bigger on the right than on the left.

9:47

The patient has a clear cut water signal cleft between the fragment

9:52

on the underlying bone, right,

9:54

rather than left and the patient has bilateral femoral

9:59

dysplasia.

10:01

How do you differentiate osteochondritis decans from an osteochondral defect?

10:05

So osteochondritis decans is a subset of defects

10:10

in the bone and cartilage.

10:12

So all osteochondral defect means is that you have a defect in the bone,

10:17

in the cartilage. So what are some of those subsets? Well,

10:20

in a patient with osteoarthritis, Kellgren Lawrence, stage two or three,

10:25

it could be a condral LASIK erosion in a patient who's had acute trauma,

10:31

it could be a defect from an acute osteochondral fracture.

10:35

It could be an unhealed fracture such as a chronic non-heated

10:40

osteochondral fracture. It could be osteochondritis decans.

10:44

These are all subsets of osteocondral defects.

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So you might introduce this case by saying there's an osteocondral defect of

10:53

the osteochondritis decans type in a juvenile.

10:57

Now I wanna point out something to you that, uh, Dr.

11:00

Thapa has pointed out in some of his pediatric lectures.

11:03

And that is it's very common to see

11:07

stippled irregular ossification centers in the, in the medial femoral conduct.

11:13

And they're usually seen in the back, in the non-weight-bearing area.

11:18

And they can produce some confusion with osteochondritis decans.

11:23

They may have a little bit of high signal in the cartilage associated with 'em

11:26

and a little bit of high signal in the bone.

11:29

They're usually stippled and multiple,

11:32

they're usually non-weight bearing. They're usually not associated,

11:36

they are not associated with an effusion.

11:40

And they occur when the growth plates are grossly open.

11:45

So the more close the growth plates appear,

11:48

the more likely such a lesion or pseudo lesion would be a real

11:53

lesion. But beware in the posterioral medial femoral condo,

11:56

you'll see multiple ossification centers and what looks like a little bit of

12:01

blistering in the back.

12:03

This is way too low and in too classic or typical location,

12:07

lateral aspect of the medial femoral con to represent the normal developmental

12:12

ossification center of the juvenile. So hopefully I've answered your question.

12:17

Odessan, a subset of osteochondral lesions or defects.