0:01

On the right side are a number of lesions

0:03

that often not always are associated with stability

0:07

of the AL joint.

0:09

Most SLAP lesions are not associated

0:12

with macro instability of the joint.

0:15

There are exceptions.

0:16

We're gonna talk a bit about that, but most are not.

0:18

So there on the right side of this table

0:24

to understand the pathophysiology of

0:26

what have been designated superior labral anter posterior

0:30

lesions or slap lesions.

0:32

Let's look at the glenoid labrum.

0:36

Once again, you're the humeral head.

0:38

You're looking mely,

0:39

and you're seeing in fear here that you're seeing cartilage

0:43

and the labrum shown here in red.

0:46

Through that labrum, I've attached only three structures.

0:49

Other structures are attached to it,

0:51

but these three are most important.

0:54

The biceps tendon, superior bunum, mal ligament,

0:56

and middle bunum mal ligament.

0:58

So let me show you what the collagen looks like in

1:01

that red labrum.

1:03

This is what it looks like.

1:05

These are circumferential collagen fibers

1:08

that typically run continuously all the way

1:11

around the glenoid.

1:13

Now of interest, a number of years ago,

1:16

someone looking at the detail

1:18

of these collagen fibers pointed out

1:20

that there was a per articular fiber system known

1:25

as PAs, PAFS,

1:28

and it connected the collagen within the labrum

1:32

to the collagen within a number of structures That to it,

1:36

here I show you three.

1:38

But other structures,

1:39

including the inferior venal ligament complex,

1:42

have a similar situation.

1:44

So it's that connection that may explain, at least in part,

1:49

the patterns of failure we'd see with slap lesions.

1:54

They probably relate to both tensile

1:57

and torque forces occurring

2:00

together rather than tensile forces alone.

2:03

And to understand that, you have to realize

2:06

that in certain positions of the arm,

2:10

particularly in abduction

2:12

and external rotation, there is a rotation

2:16

of the biceps tendon shown by the blue owl

2:18

as it rotates more posteriorly.

2:22

So let me show you why that occurs.

2:25

It occurs in external rotation,

2:28

shown in the left side of that drawing.

2:30

At the bottom, you can see what happens.

2:33

The biceps tendon rotates backwards, right compared

2:37

to neutral and internal rotation.

2:40

And that produces tensile

2:42

and torque forces that are placed

2:46

on the uh, uh, labrum.

2:49

And because of that, what can occur is a

2:53

peel back lesion here, shown in this drawing,

2:57

a peel back lesion

2:59

As the biceps tendon twist,

3:02

producing a pathologic separation

3:04

or detachment of the labrum,

3:06

which can be seen in the a bear position, abduction,

3:11

external rotation by drawing a line tangent to the glenoid

3:15

margin and seeing that all of that posterior labrum is

3:21

posterior to that uh, line of the articular surface.

3:26

So this is a peel back lesion.