0:01

So let's go three up here, three up.

0:05

And let's start out with our, our three,

0:08

uh, coronal projections.

0:09

There's quite a few images in this case.

0:11

On your left, we've got the T one spin echo,

0:15

and you can see there's some proac

0:17

or blood tinged fluid in the joint.

0:20

We've got a fat suppressed, uh, water weighted image, uh,

0:24

likely a proton density, fat suppressed image.

0:27

And on your far right, a non-fat suppressed T two.

0:32

And right away you can see that close

0:35

to the 12 o'clock position within a centimeter

0:38

or two, within 10

0:39

or 20 degrees, which is typically

0:41

where you'll find them from the apex.

0:44

Slightly more lateral is this depressed hill

0:47

sax abnormality.

0:50

Now, as we scroll back and forth, I look at the T one

0:53

and the, and the water weighted image,

0:56

because sometimes it's hard to tell

0:57

where the cortex stops and or begins.

1:01

You can see this depression right here,

1:03

and what I, what I like to do is put up my axial

1:08

and I'll measure my axial.

1:10

And this one, let's measure the length of the, the hill sax

1:13

or the width of the hill sax and the axial projection.

1:17

And we're getting a measurement of about 1.3 centimeters

1:21

or 13 millimeters.

1:23

Now let's look at the, let's look at the coronal projection,

1:28

and I'm gonna obliquely it.

1:29

I'm gonna go into my oblique tool,

1:32

and you'll have to forgive me.

1:33

This one's slightly different than the one I'm used

1:35

to using, and I'm gonna try

1:39

and get as close to, let's see if I can get it to work.

1:45

Here we go. I'm gonna try

1:48

and get as close to tangent to the posterior aspect

1:52

of the humerus as follows.

1:53

So let's do that. I'm gonna get right back on my hill here

1:58

in the back, and that gives me a very good idea

2:02

of the width of the hill sax.

2:03

And you, you see how it parallels the track, uh,

2:07

of the glenoid track, uh,

2:09

to use a redundant term track and track.

2:11

And if we measure it at its widest portion,

2:15

it's gonna measure about 13 to 15 millimeters, somewhere in

2:19

that, in that vicinity.

2:21

So that's a quick way, uh,

2:23

to figure out the width of the hill sacs.

2:25

That's a little more accurate than simply measuring the

2:28

axial, which often underestimates the width

2:31

of the glenoid track.

2:32

Now let's do something different.

2:34

Let me see if I can get out of this.

2:36

I think I've gotta go out

2:37

and in again, Paul, I'm kind of stuck here.

2:41

Thank you. I don't know that it'll let me do that.

2:46

Um, let's go to the sagittal projection.

2:50

Is there any way to one up them?

2:52

Probably not, but here's a quick way.

2:55

As Don promised you, I would give you a quick way to

2:58

Figure out the, the glenoid track.

3:02

And I'm gonna use my pen here rather

3:05

than my measuring stick.

3:08

And I'm going to measure the, an posterior dimension,

3:12

pardon the little waviness of my hand of

3:15

where I think the pair, the edge of the pair should be.

3:19

So there, there's my circle right there.

3:20

Now, I could do a best fit circle

3:22

and use the circular tool up top,

3:24

but I usually use my eye to do that,

3:26

and it's pretty accurate to make that curve.

3:29

And then I get a, a, a length here,

3:31

and then I multiply that by 0.83,

3:33

and I do that very quickly.

3:35

So I just put a line on there.

3:38

Let's say it measures 2.5, which it, it kind of did.

3:41

I multiply it by 0.83, and that gives me 2.2.

3:46

But then I have to subtract, I have

3:49

to subtract this little area here

3:50

where I've lost some of my glenoid.

3:53

And I could take another color

3:56

and measure that just for fun using another color.

3:59

And I measure that, and that's gonna be about

4:01

four millimeters.

4:02

So now I take my 2.2 measurement,

4:05

which I got from measuring the glenoid cup,

4:09

multiplying by 0.83.

4:10

I got 2.2, I subtract four millimeters. And what do I get?

4:15

I get 1.8 or 18 millimeters.

4:18

So the bottom line is my glenoid track width

4:22

of 18 millimeters is wider than my

4:26

hill sacks width, which turned out to be about 13

4:30

to 15 millimeters.

4:31

So we'd say that this is more likely going to be a unipolar

4:36

on track abnormality.

4:38

Now let's see if we can look at the, the abnormality itself.

4:43

Let's pull down an axial.

4:49

And you know, when you lose the entire labrum,

4:52

you really get this feeling like you've lost bone.

4:56

Now, you can lose bone from compression from repetitive

5:00

impaction as don described,

5:02

but when you have that labrum missing, it,

5:04

it almost looks like

5:06

but isn't real, that you've lost

5:08

glenoid bone, but you haven't.

5:10

It's just that you've lost the glenoid triangle.

5:13

And there it is floating in the breeze, uh,

5:16

markedly displaced, uh, from the glenoid.

5:19

And the glenoid is a little bit rounder

5:21

and attenuated anteriorly.

5:23

Uh, this was not at least known to me a recurrent dislocate

5:26

and is usually the case in performance.

5:29

Athletes like this individual, there's a little bit

5:31

of irregularity in a small tear in the posterior

5:35

aspect of the labrum.

5:36

But I wanted to use this case to give you a method

5:40

for looking at the track.

5:41

Now, here's another quick method that I use routinely.

5:45

Let's go back to the sagittal.

5:50

And most of you know, es especially my visiting scholars

5:54

and former fellows, that I don't like

5:55

to measure things because

5:57

My former mentor, Dr. Benjamin Filson told me that people

6:00

that that measure things are not sexually active.

6:04

So I try not to measure too frequently.

6:07

Uh, and, and here's what I do.

6:09

I, I look at the glenoid and I bisect it.

6:15

So I have it on Foss in the sagittal projection,

6:20

and I know about where the glenoid would've been.

6:23

And then I, I put a little.in the middle

6:26

and I do this with my I.

6:28

And then I have a radius in the back radius in the back,

6:32

a radius in the front right here.

6:34

And if I have half of that radius involved, so

6:40

half of that radius would be about 25% of the width

6:45

of the Glenwood cup, then I know that I potentially

6:49

and likely have a problem.

6:51

What's the number that I use to tip me off

6:54

that there could be an engaging lesion about 12 to 14%,

6:59

as low as 12% I've seen with an engaging lesion.

7:03

So 25 is the number in the literature,

7:05

but that's not a hard fixed number

7:07

because there are a lot of other factors at play.

7:10

The size of the hill sax, the orientation of the hill sacks

7:14

with the arm in abduction.

7:15

If the hill sacs is parallel to the inferior aspect

7:19

of the glenoid, you're much more likely

7:22

to have an engaging scenario.

7:25

So let's move on to the next case.