0:01

The next pattern

0:02

of Sid in the proximal carpal row is lunar

0:05

triquetral dissociation.

0:08

This is a fairly common instability pattern

0:11

that is typically associated with VC deformity, okay,

0:15

where we have lar tilting of the lunate.

0:19

But note, there's palmar flexion of the scaphoid.

0:22

These two bones move together, the disruptions

0:26

between the lunate and the triquetrum.

0:30

All right? And I'll show you some examples of that.

0:33

So here is the typical mechanism of injury that I've seen,

0:36

axial loading, external rotation

0:40

and ulnar deviation, perhaps falling backwards as shown in

0:44

that particular picture.

0:46

And typically what happens is tearing of the luno triquetral

0:51

interosseous ligament bay, which you can see here,

0:54

and often tearing of the volar, radial lunar triquetral,

0:59

or long radial lunate ligament.

1:02

So let's look at a case first using Go Lula's rules, right?

1:07

Let's look at that first arc.

1:09

So that's broken right here between the lunate

1:12

and the trium.

1:14

Let's look at the second arc.

1:16

And that's broken between the lunate and trium,

1:20

and there's a name for that.

1:22

That appearance is called the seagull sign.

1:25

The disruption in the Lula line too.

1:29

You can see the lar tilting of the lunate very, very nicely

1:33

in the lateral radiograph.

1:35

To show you an example of that with Mr,

1:38

there is palmar flexion of the scaphoid.

1:41

The lunate is following the scaphoid.

1:44

So there's no dissociation between the scaphoid and lunate.

1:49

The problem is between the lunate and the triquetrum.

1:53

So the scap, scaphoid and lunate move together,

1:56

but the lunate or the trium does not follow those two bones.

2:01

And in some cases, in late stages, the dorsal radio

2:06

triquetral ligament may also be torn in air.

2:09

The seagull side, all the third cause

2:14

of Sid in the proximal carpal row are scaphoid fractures.

2:19

Now, this is related not to problems with the ligaments,

2:22

but to rotation that occurs at the site

2:25

of the scaphoid fracture.

2:27

So the proximal fragment rotates

2:30

with the row, okay?

2:33

But that distal fragment will flex volar.

2:38

Okay, so let's look at that.

2:40

This results in what has been called a humpback deformity.

2:44

Okay? This is what it would look like.

2:46

So I'm showing you that a volar tilting

2:49

of the distal fragment, here's the proximal fragment,

2:52

still connected to the lunate.

2:55

So it will not tilt. The rotation occurs at the

2:59

Fracture site, right?

3:00

It looks like a humpback,

3:03

the dorsal surface of the humpback.

3:05

And you can see very nicely its appearance on mr.

3:09

Those are the two fragments of the scaphoid.

3:12

The lunate is following the proximal pole,

3:16

which is Dorsey flexed.

3:18

So this is the third pattern.

3:20

And over a period of time, something called the

3:23

snack wrist may occur, scaphoid non-union advanced collapse

3:28

that may occur in longstanding uh cases.

3:31

Here's the longstanding non-union of the scaphoid.

3:34

There was osteonecrosis of the proximal pole.

3:38

The arthropathy develops between the radial styloid

3:42

and the distal pole.

3:43

That's the characteristic site,

3:46

and there may be mal alignment elsewhere in the wrist.

3:49

And then finally, the fourth cause of Sid

3:53

in the proximal carpal row is kBox disease.

3:57

And that's not hard to understand.

4:02

In the later stages of kBox disease,

4:06

there is collapsed fracture

4:07

and fragmentation of the bone, the spaces between it

4:11

and its small size.

4:13

And the Sid and

4:15

and uh uh, triquetrum widen owing to failure.

4:19

As you can see with the intervening ligaments.