0:00

Now with that as background to anatomy, let's begin

0:03

to talk about injuries.

0:04

And we're going to talk about chondral

0:06

and osteochondral fractures of the tailored dome.

0:11

These are more common than fractures, similar fractures

0:14

of the tibial PlayOn.

0:16

They will, uh,

0:18

typically occur more frequently on the medial side, okay,

0:22

than on the lateral side or central portion.

0:26

And indeed on the medial side,

0:28

these are the two most common locations we see central

0:32

medial and postal medial.

0:34

On the lateral side, the classic places are anterolateral

0:39

or central lateral.

0:40

Okay? Those are the places

0:42

that we typically see the injuries.

0:46

When we look at the injuries, they tend to be larger

0:49

and deeper on the medial side

0:51

and probably relate to compression.

0:54

When we look at the lesions on the lateral side, they tend

0:57

to be smaller, they're more shallow,

1:00

and they may relate to sheer injury

1:03

and we'll get back to the pathogenesis a little bit later.

1:07

So these fractures typically relate to a single episode

1:12

of trauma, although occasionally on the medial side,

1:16

a stress injury can eventually produce a fracture in

1:20

that particular area.

1:22

And in most of these injuries,

1:24

there are associated ligamentous abnormalities.

1:28

Now, there's no single classification system to describe

1:32

chondral and osteochondral fractures of the Taylor Dome,

1:38

but the one that I think is most useful was put forth

1:42

by James Griffith from Hong Kong,

1:44

and I'm using a few of his slides here.

1:47

You can see in fact the various grades

1:50

that he suggested running from grade one,

1:53

which is a more minor finding to grade five.

1:57

And this relates to the status of the articular cartilage,

2:01

the subc chondral bone plate, and the subchondral bone,

2:04

and whether or not there is osteochondral separation

2:09

of the involved tissue.

2:10

Here you can get a general idea of the increasing severity

2:15

of the abnormality.

2:16

So let me show you a couple of examples.

2:19

This would be a grade one B lesion.

2:23

We can see here areas of marrow edema on both sides

2:27

of the joint and a cartilage fracture well illustrated here.

2:33

This would be a grade two B lesion.

2:36

Here we deal with subc chondral bone collapse

2:39

with osteochondral separation, the separation shown

2:44

by the black arrows.

2:49

Now what's interesting when we have these particular

2:53

injuries, we can end up with intraarticular bodies

2:57

with a chondral fracture.

2:58

The body is composed of cartilage alone

3:01

with an osteochondral fracture, both cartilage

3:04

and bone represent the constituents

3:07

of the intraarticular body.

3:10

Here we can see example of an osteochondral fracture

3:14

with slight separation of a body composed

3:18

of cartilage and subcon bone.

3:21

Now typically, as we've mentioned previously in this course,

3:24

these bodies may remain at their site of origin,

3:28

may become slightly displaced, as shown here,

3:32

become totally free

3:34

or loose, migrating around the joint

3:37

as they migrate around the joint.

3:39

The cartilage may grow nourished by synovial fluid

3:43

through the process of endochondral bone formation

3:47

and bone is created often in a layered fashion.

3:51

The bony aspect of the body,

3:53

however, generally undergoes necrosis when you look

3:57

for these, these bodies in any joint always look

4:01

for in the joint recesses because they tend to lodge

4:04

or extend into those recesses, and eventually they may lodge

4:09

and become fixed in the synovial membrane.

4:13

And at that point, they may change size by resorb.

4:18

Now, one of the interesting problems,

4:21

diagnostic problems we have about the ankle is the

4:24

differentiation of intraarticular bodies from ossicles.

4:29

I'm showing you at the top scle.

4:32

These are fragments of bone that can be located

4:35

beneath the medial maus as shown here,

4:39

or in fact beneath the lateral mala.

4:42

And although, although there are books that suggest

4:45

that normal variations may have this appearance much more

4:50

frequently, you're looking at post-traumatic

4:52

separated pieces of bone that have not fused

4:56

with the parent bone.

4:57

So those, if you put an arthroscope in the joint,

5:00

would not be visible.

5:02

Compare that to intraarticular bodies. Here's an example.

5:06

This one very near the medial ligament is complex.

5:12

So these are true intraarticular bodies,

5:15

but differentiating ossicles typically related for

5:19

to fractures from intraarticular bodies, sometimes,

5:23

particularly in the ankle, can be difficult.

5:27

Well, let's look at an illustrative case here.

5:30

This is a young man with pain and swelling about one

5:34

or two weeks after an injury.

5:36

The black arrow are showing you evidence

5:38

of an osteochondral injury in the form of an osteochondral

5:44

fracture, which has led to a displaced intraarticular body,

5:49

composed obviously of cartilage and bone.

5:52

Let me go ahead and displace it.

5:54

And now I want you to look at this. This is on

5:56

The lateral aspect of the Taylor Dome, often related

6:00

to sheer injuries.

6:01

And because of that, it's not unusual that

6:05

that body is actually upside down,

6:08

and you have to recognize that

6:10

because generally surgery would be required

6:13

to rotate this body and perhaps fix it back in place.

6:18

Here's another example, just to show you the same point,

6:21

particularly with fractures of the lateral Taylor Dome.

6:26

If they displace, if they become loose

6:28

or free, they may invert

6:31

and you should look for that,

6:33

be it on conventional radiographs, uh, CT or Mr.

6:38

Images.