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<v ->Now we have some other words that we use in our language

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and when we describe what we see on the MR,

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and two of those words are chondral injury

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and osteochondral injury, and they are different.

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Chondral injury means that the force applied to the surface

0:19

of articular cartilage is dissipated

0:23

in the articular cartilage

0:25

and does not reach the subchondral bone.

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An osteochondral injury indicates that that same sort

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of force, perhaps greater magnitude,

0:37

is resisted not only by the articular cartilage,

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but also, it reaches the subchondral bone.

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Okay, as shown here, that then is an osteochondral injury.

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Osteochondral injuries are easy to see, and why is that?

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Because with these injuries,

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there is a light bulb in the subchondral bone,

1:04

okay?

1:05

On the fluid-sensitive sequences.

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So as soon as you see a bright spot here,

1:12

you're not dealing with a simple chondral injury,

1:16

you're dealing with an osteochondral injury.

1:19

So here, we have an osteochondral injury manifest

1:23

as a chondral fracture,

1:26

producing a chondral defect

1:28

with an intact subchondral bone plate

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and subjacent bone contusion.

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And by the way,

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observe how sharp those edges are

1:40

to a traumatic chondral defect.

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When we talk about a chondral injury,

1:49

the light bulb is off

1:51

because the force does not reach the subchondral bone.

1:56

So when you think about it,

1:57

we're terrific at picking up osteochondral injuries

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and we are poor at picking up chondral injuries

2:06

unless you're dealing routinely with 3-tesla

2:09

or or even 7-tesla magnets.

2:12

Here shows that point, here's the initial study,

2:15

following an injury read as negative.

2:18

Nine months later, delamination at the tidemark, right?

2:24

Bright signal, curvilinear signal.

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So the cartilage was injured,

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it's just that we didn't see it initially

2:32

on the first MR examination.

2:36

So my advice to you is when a group

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of orthopedic surgeon comes into your area,

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and I've learned they never come in by themselves,

2:46

they come in as a group, overwhelming you with numbers.

2:51

And when they hold up that particular image

2:54

that you're glancing at on your computer,

2:58

and they ask you, "What is happening here?"

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And you say, "Well, I see a bone contusion here."

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And they say, "Well, that's easy to see.

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Anybody could see that."

3:10

What they wanna know is what's gonna happen

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to the articular cartilage.

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You better answer, "We can't be certain,"

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because it's hard to predict exactly what's gonna happen

3:23

to the articular cartilage.

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They might not be happy with that answer,

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but that's the truth.

3:29

Here, it looks good.

3:31

11 months later,

3:32

there is a chondral defect that has developed.

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Note that the contusion is almost completely resolved.