0:01

20-year-old male, baseball pitcher, who recently dislocated,

0:07

and he's got an anteromedial pattern of bone injury,

0:11

mostly intramedullary involving anchondral or spongy bone.

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The sagittal projection shows the anterior

0:18

location, which is typical of a reverse Hill Sachs

0:22

equivalent, or posterior dislocation event.

0:26

So now we're working out the back.

0:29

We have an axial gradient echo in the

0:30

middle, a PD, fat suppression on the left,

0:33

and a T2, fat suppression on the right.

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We're pretty much done with the sagittal, um, unless

0:40

we had a bunch of paralabral cysts, which we don't,

0:43

but we do see the extent of inflammation up and down,

0:47

and typically, the frequency of posterior caudal labral

0:51

tears in posterior dislocation is greater than the

0:55

ones that are mid to superior, as you would expect.

0:58

Similar to anteroinferior labral

1:01

tears that occur in the front.

1:04

And the order of things is an injury to the labrum, then

1:08

the capsule, then the muscular tissues, and the periosteum

1:12

together, or the periosteum and then the muscular tissues.

1:15

So there is kind of an orderly progression of things.

1:18

If we look at the posterior labrum for a moment,

1:22

there are some striated, very scant, lacy signals.

1:25

In the labrum, there is a partial separation

1:29

of the labrum, but hanging on right there is a

1:34

portion of the labrum attached to the periosteum.

1:37

So you have maybe just a little bit of periosteal

1:40

elevation, hardly any, very little labral displacement,

1:44

and no detachment of the capsule from the point of

1:49

the labrum, nor is there injury of the posterior cuff.

1:53

Which can also happen with dramatic dislocations.

1:56

Or the anterior cuff, which can

1:58

happen with dramatic dislocations.

2:00

So we would refer to this as a reverse Perthes lesion.

2:04

It's a minimal labral tear.

2:06

It is a non-surgical labral tear.

2:08

And we like not to repair the tears

2:11

in the back if we don't have to.

2:13

Because they, they're, they're pretty vascular areas.

2:16

They have a good propensity for

2:17

granulating in because of this vascularity.

2:20

And, and healing on their own.

2:23

Now the rest of the pulsing sequences really

2:26

don't add a tremendous amount additionally.

2:29

Uh, the axial does demonstrate, by the way, the

2:31

intact periosteum, the intact musculature, the

2:34

intact remaining capsule, the intact posterior

2:38

rotator cuff, and this should all be part of The T1

2:43

weighted image shows again the anteromedial component

2:46

of the bancard, and perhaps shows it as a little

2:50

more severe than you otherwise might have expected.

2:54

This is an example of an acute unidirectional event

2:58

in a young man with a resultant Perthes type lesion,

3:02

which we said when we discussed it anteriorly in another

3:06

vignette, That can occur as a result of multidirectional

3:10

instability, micro-instability, unidirectional micro

3:14

instability, or a single traumatic dislocation event.

3:19

So it's got a lot of, a lot of

3:21

variability in its presentation.

3:24

Posterior dislocation of the shoulder.