0:01

Let's now turn our attention

0:03

to the less well-known various postal medial

0:06

rotary instability.

0:08

PMRI.

0:10

This has been described more recently

0:14

and it is associated with a fracture,

0:17

although it looks like a minor fracture in some cases.

0:20

It's related to a OID process

0:24

fracture in the area of the,

0:26

an anter medial facet of the oid.

0:31

It occurs when an axial load is applied to the elbow

0:34

with various alignment.

0:36

And what occurs is internal rotation

0:40

of the forearm shown here, leading

0:43

to a shearing fracture of the antral medial facet

0:48

of the coronoid process with classic injuries

0:51

to the lateral ligaments

0:53

and to the posterior bundle

0:56

of the medial collateral ligament.

0:59

PMRI.

1:01

Now, one mechanism shown here is a fall on

1:04

behind when the the arm is behind the body.

1:08

This will create the ideal situation for PMRI.

1:13

The final stage typically is a subluxation

1:16

and not a dislocation of the elbow.

1:19

So let's go back and just show you this.

1:21

Hopefully it'll work. This is PLRI related

1:25

to a valgus injury with axial loading, leading

1:29

to external rotation of the forearm,

1:32

beginning laterally extending medially

1:35

and ending up with that Osborne CRE lesion

1:38

that we talked about, the posterior aspect of the Capella.

1:43

Now let's look at posterial, medial rotary

1:46

and stability of various injury with axial loading, leading

1:50

to internal rotation of the forearm elbow subluxation,

1:56

and then this distinctive fracture in the area of the,

1:59

an medial facet of the omen.

2:03

By the way, this is from a rad source web clinic.

2:06

Mike Stadnik, one of their owners, made these, uh,

2:09

we wrote, we wrote it.

2:10

If anyone's interested, you can go back to the RAD source

2:13

and find the web clinic

2:15

that we wrote on this probably about four or five years ago.

2:18

Here's what it looks like with stress testing

2:21

and you can see the lateral ligamentous injuries

2:24

with widening of the, of the radial aspect.

2:27

Now, let's go back to the, the anatomy of the Corona process

2:33

here, and we're looking in the transverse plane

2:37

and let's go over those types one more time.

2:40

Type one fracture of the corona process is right here.

2:43

It involves the hip. This can be seen with a terrible triad.

2:49

Also in some cases A-P-L-R-I,

2:52

it does not involve the sublime cubicle, okay?

2:56

And rarely involves the, an medial facet.

3:00

Remember that was located here, the tip, the facet,

3:04

and the tubercle.

3:07

Okay? The type three shown here

3:10

involves more than 50% of the coronary process.

3:14

This is a typical finding with a liquin on

3:18

fracture dislocations, and there are subtypes of it.

3:22

I'm not gonna be going into it.

3:24

The fracture that's associated with PMRI

3:29

is a type two fracture.

3:31

Uh, and there are three subtypes of it, often labeled one,

3:35

two, and three.

3:37

Now we're gonna be talking about those,

3:39

but you can see in fact the antral medial facet is involved

3:43

here in the subtype one, right?

3:48

If we look at subtype two, that facet along with the tip

3:52

of the OID is involved.

3:54

And if we look at subtype three, it involves

3:58

both the antral medial facet

4:00

and the sublime cubicle with

4:03

or without involvement of the tip.

4:06

So those are the Elon patterns that we look for.

4:09

Now, I don't know how many of you already spend time trying

4:12

to figure out what part of the coronary processes involved,

4:16

but I think you might wanna consider doing this.

4:19

So let me show you some examples.

4:21

This one by ct, this is a fracture involving both, uh,

4:26

or involving the antral medial facet and the OID tip.

4:30

So it's a cond fracture involving the tip,

4:34

and the tip fracture is shown by the red arrows

4:37

and the antral medial facet.

4:39

And you can see that by the yellow asterisk in the, in that

4:44

and spares.

4:46

The sublime tubercle, which is located over here

4:49

with the green arrow head, is evident.

4:52

So this is a type two subtype two fracture.

4:56

Here's another one. This is a type two subtype one fracture.

5:01

'cause the only thing that is fractured is the

5:03

antral medial facet.

5:05

So here we can see the intact sublime tubercle.

5:09

Here's the fracture of the facet.

5:11

You can see the involvement of the lateral ligaments here.

5:15

The tip of the coronary process is intact.

5:18

The, an medial facet is not intact, it is fractured.

5:24

So you look at a radiograph here

5:26

and you're not gonna see much if you look very closely,

5:29

you'll see a second curve linear line above

5:32

that radial head.

5:34

That is one of the subtle radiographic

5:36

findings that may be present.

5:38

Here's another one, type two subtype, one fracture.

5:42

You look at the radiographs

5:45

and you're seeing the tip of the OID and it's intact.

5:49

Let's go ahead and look at the MR images.

5:53

And here is the intact sublime cubicle.

5:57

Here's the fracture

5:58

of the an medial facet shown nicely here

6:03

and here and here.

6:04

This is not the tip of the oid. It is medial to the tip.

6:09

So this is a subtype one, uh,

6:13

type two fracture.

6:14

This is PMRI. I'll show you one or two more.

6:18

This is type two subtype two fracture, a fracture

6:23

of the antral medial facet, and the coronoid tip here.

6:27

Beautifully shown fractures of the tip

6:30

and of the antral medial facet

6:33

with an intact sublime tubercle.

6:36

We go to the sagittal plane. Here is the tip fracture.

6:39

We move more medially.

6:41

Here's the fracture of the antral medial facet

6:44

in the coronal plane.

6:46

The bone avulsion where the posterior bundle

6:49

of the medial collateral ligament attaches.

6:52

Remember I said that bundle may be involved lateral ligament

6:56

problems as well.

6:57

And again, the fracture clearly shown in the coronal plane.

7:02

So I know these are subtle,

7:04

but if you spend your time, particularly if you're doing ct,

7:06

I think it becomes more obvious.

7:09

Now, I just wanna finish up this part

7:11

of my lecture showing you a few specific ligament tears.

7:17

This is what PLRI looks like.

7:20

You can see the radial head behind the Capella,

7:23

and there's the lateral ulnar collateral ligament,

7:26

which is torn distally, displaced proximally.

7:31

Here I wanted to show you an example of a tear

7:34

of the radial collateral ligament.

7:36

A large tear occupying a, a distance of that ligament.

7:42

Lateral ulnar collateral ligament, probably part

7:44

of this tissue is intact.

7:48

Here is a fracture involving the, uh, humerus

7:53

where the radial collateral ligament attaches

7:55

and extended over onto the osteochondral surface.

7:59

And here is an injury involving the

8:03

involved, actually both bundles.

8:04

But here I'm showing you the involvement

8:06

and tearing of the anter, uh, bundle

8:09

of the medial collateral ligament.