0:00

We're gonna move on and finish up in the last 10 minutes

0:04

or so with carpal instability complex.

0:09

This is an instability pattern that has features

0:12

of both Sid and Sind.

0:14

Alright? And I've listed some of the conditions

0:16

that fit in this category.

0:19

The dorsal per illuminate dislocation,

0:21

the dorsal per illuminate fracture dislocation.

0:25

There rarely may be a palmar per illuminate dislocation.

0:29

They're not gonna be covering axial dislocations.

0:33

So all dislocations except radial carpal dislocations

0:37

all into this category.

0:40

To understand carpal instability, complex CIC, we have

0:45

to remind ourselves about the greater and lesser arcs.

0:49

So let's first talk about the lesser arc injuries

0:53

of the lesser arc that we've talked about earlier.

0:55

To remind you are can be antegrade

1:00

shown here, circling the lunate with

1:05

stages of injury.

1:06

All right, I think we've all seen that.

1:09

Now, there's another pattern that you may not know.

1:11

I call it the extended antegrade pattern.

1:15

And look what happens with this pattern goes

1:17

around the lunate, but then it's a fracture.

1:20

The failures in the triquetral bone,

1:23

so often a sagittal fracture.

1:25

Let me show you an example. Here's an example.

1:28

So you can see here the widening

1:30

of the scapholunate interosseous space, tearing of

1:33

that ligament and other extrinsic ligaments.

1:37

And indeed then the injury went around

1:39

and came through as a fracture

1:42

through the triquetrum as shown here.

1:45

So this is the extended antegrade pattern of a lesser

1:49

or injury retrograde goes in the opposite direction.

1:53

We mentioned it before.

1:55

It's classified as a, uh, dissociative

1:59

luno triquetral problem.

2:01

So it's not in this classification.

2:04

And then the greater arc, you all know this is a,

2:08

as many fractures as you possibly could have.

2:10

You don't have to have all these fractures.

2:13

Transradial, styloid, trans scaphoid, trans capitate,

2:18

transaid, trans TriCal,

2:20

and I threw in trans ulnar styloid as well.

2:23

So this is the maximum greater arc injury.

2:27

So let's talk about the lesser arc

2:30

and go through dorsal per lunate dislocations.

2:34

Clearly you have seen these because this is a common injury.

2:38

It goes through four stages.

2:41

The final stage

2:43

where the lunate is dislocated in a lar direction,

2:49

attached mainly

2:50

by the short radial lunate ligament shown here.

2:55

And there's obviously narrowing

2:56

between the radius and the distal

2:58

Carpal row.

3:00

In each of these four stages, certain

3:05

abnormalities are present.

3:07

Scap lunate dissociation, progressive tearing

3:10

of the scap lunate ligament,

3:11

and some of the extrinsic ligaments

3:14

who NATO capitate dissociation.

3:17

Stage two, tearing of the volar capsule at the space of

3:22

which we talked about earlier.

3:25

The third stage, luno triquetral dissociation,

3:29

progressive tearing of the luno triquetral

3:31

interosseous ligament.

3:33

And then the final stage four lunate dislocation,

3:38

volar displacement, and rotation of the lunate.

3:42

So just to show you that final stage,

3:45

this is what it would look like.

3:46

Diagrammatically. This is the short radial lunate ligament.

3:50

You can see the capitate wedge between the lunate

3:53

and the radius.

3:55

And here it's displaced even further.

3:59

Uh, in that part of the, of the drawing, you have

4:03

to have failure of all per illuminate ligaments,

4:05

except the short radio lunate ligament.

4:08

You get lar displacement and rotation of the lunate.

4:12

So here's an example.

4:14

It's hard to get these, but here's one.

4:16

So this is a stage four problem.

4:19

The lunate is sitting down here through the space of er.

4:23

I showed you a similar image earlier on.

4:26

It's not sitting in its normal position. By the way.

4:29

There were problems with the TFC.

4:32

You can see the displacement and rotation of the lunate.

4:37

Here is the short radial lunate ligament

4:39

still attached to it.

4:41

And in this case, we could also follow the volar radial

4:45

lunar triquetral ligament, which appeared to be intact.

4:51

So when we talk about per lunate dislocations

4:55

and lunate dislocations, they're part

4:57

of the, the same spectrum.

5:00

Classically, what occurs is a peric capitate

5:03

displacement dorsally.

5:06

Okay? The distal row goes dorsally,

5:08

and then when it comes back into place,

5:11

it knocks the lunate out in a lar direction.

5:17

Now, we also deal with certain fracture dislocations,

5:21

the most common, one of which is a dorsal peri lunate

5:25

fracture dislocation.

5:28

This is a greater arc injury.

5:31

All right, and just to show you a picture of it

5:34

and an example of it, this is a

5:38

trans scaphoid per lunate fracture dislocation.

5:42

You can see the abnormal position of the lunate.

5:45

The typical place of the scaphoid fracture

5:49

is in fact through the body.

5:51

The middle third, it occurs in about 60% of persons

5:55

who have per

5:56

Illuminate dislocation.

5:58

And the proximal fragment generally is still

6:02

connected to the lunate.

6:03

Here's what it looks like.

6:05

You can see the fracture, you can see the displaced lunate

6:09

and the position of the capitate.

6:13

And then the final condition that I wanna just, uh, uh,

6:17

talk about is a trans scap, trans capitate

6:22

per lunate fracture dislocation.

6:25

This is a variation of the greater a injury.

6:27

It's often designated the scap o capitate syndrome.

6:32

And the importance of it

6:33

in particular is one point that I would make.

6:36

Here's the fracture, all right?

6:38

Through the scaphoid

6:39

and through the capitate, the displaced lunate.

6:43

But when you look at radiographs or cts

6:46

or Mrs following this injury, you've gotta look very,

6:50

very carefully at that capitate,

6:53

because this is one of the fractures in which

6:56

that fragment may rotate 180 degrees,

7:00

which it has done here.

7:02

Clearly, this should be the proximal surface,

7:06

not the distal surface.

7:07

So be aware of that rotary subluxation that occurs

7:11

with the trans boy, trans capitate per lunate,

7:16

fractured dislocation.

7:17

So what I've done in my allotted, uh, period of time is

7:21

to cover a lot of material.

7:23

We followed this particular outline, pretty much

7:26

followed it just as it's written.

7:29

I realize again, uh, for the beginners out there,

7:32

this is might be a bit overwhelming.

7:35

But I really believe, particularly with stronger magnets

7:39

that are being used to study the wrist

7:41

that we now can visualize, well, both intrinsic

7:45

and extrinsic ligaments.

7:47

And the orthopedic surgeons, specifically the hand surgeons,

7:52

will be turning to us to ask us

7:55

to analyze the patterns of instability.

7:58

They wanna, they're gonna wanna know which ligaments are

8:01

intact, which ligaments are torn, what are the positions

8:05

of the various carpal bone.

8:08

So hopefully this information will help.