0:01

Okay, we're ready to talk now about elbow stability

0:04

and instability and elbow fractures

0:07

and fracture dislocations.

0:10

I'm gonna indicate a few anatomic considerations, general

0:14

considerations that are important.

0:16

First of all, the stabilizers of the elbow joint are very,

0:21

very similar to the defenses of a fortress.

0:26

They have an outer wall

0:27

and an inner wall, as I'll show you in the next slide.

0:30

Some of them are primary stabilizers

0:33

and I've listed three major ones there.

0:35

Some of them are secondary stabilizers, meaning

0:39

they become more important when one

0:42

or more of the primary stabilizers are disrupted.

0:47

So let's look at the outer wall of our fortress consisting

0:52

of three static stabilizers.

0:55

The all no humeral joint, which is the lock

0:58

of the elbow joint, the anterior bundle

1:01

of the medial collateral ligament,

1:03

and the lateral NAR collateral ligament.

1:07

These are three very important static stabilizers

1:11

that create the outer wall.

1:14

The inner wall consists of two dynamic

1:18

and one static stabilizer.

1:20

The static stabilizer is the radiohumeral

1:23

portion of the joint.

1:24

It's important, particularly when something else goes wrong

1:28

in the outer wall.

1:30

And here the two dynamic stabilizers,

1:33

the common flexor pronator tendons,

1:35

and the common extensor tendon.

1:39

Number two of those three regions of the elbow joint.

1:44

The humal aspect,

1:46

or we'll call it the humal joint, is the key stabilizer.

1:51

And as I've mentioned, it consists of anon

1:55

and a OID process.

1:58

Loss of integrity of that OID process

2:02

is bad for elbow stability.

2:05

It disrupts the trochlear notch that we know is so important

2:09

and it may disrupt the anterior bundle

2:12

of the medial collateral ligament.

2:14

It kinda looks like the trochlear tr uh,

2:17

it looks like in fact a spool of thread.

2:22

So this is the lock, the trochlear trochlear notch part

2:26

of the joint, and I think it's well shown.

2:29

This was a recent section

2:30

that I came across in our previous material.

2:35

And look how this really serves as the elbow lock

2:39

locking the joint.

2:42

Now, that's going to explain

2:43

as I'm gonna talk about in a few minutes, why of many

2:46

of the injuries because of this lock are

2:50

fractured dislocations and not pure elbow dislocations.

2:55

So if we try to analyze this trochlear

2:58

Notch using conventional radiography, we can use the

3:03

o uh, the lateral view of the elbow.

3:06

We draw a line along the long axis of the ulnar,

3:10

a second line at the touching the tip of the I liquin on tip

3:14

of the coronary process.

3:16

And the typical angle

3:19

between those lines is 30 degrees.

3:22

Now if we start getting fractures

3:24

of the OID process shown here,

3:27

those angles will become more parallel

3:30

and that is certainly abnormal

3:33

unlocking this very important lock of the elbow joint.

3:38

And this has led to a

3:41

classification system in the sagittal plane for fractures

3:45

of the OID process.

3:47

The type one involves only the tip of the process.

3:52

Type two involves less or, or 50%

3:56

or less of the height of the OID process.

3:59

And type three involves more than 50%.

4:04

So this is a system that is used by, uh,

4:07

some orthopedic surgeons.

4:09

Now if you have a type three fracture that is very low,

4:12

it does something else, it will disrupt the attachment

4:17

of the brachialis muscle

4:19

and tendon further destabilizing the elbow joint.

4:25

Now there is another classification system

4:28

that is gonna become very important a little later in this

4:31

particular lecture.

4:33

And it's based on findings in the coronal plane.

4:37

The anatomy of the OID process in the coronal plane is

4:41

very complex.

4:43

There is a tip of the OID process we can see here.

4:47

And next to the tip are flattened regions shown here,

4:52

one lateral, one medial incorrectly.

4:55

They are called facets,

4:58

although that is not correct anatomically we are gonna use

5:01

the term the anterolateral facet

5:04

and the ant medial facet a little bit later

5:07

on in this lecture.

5:09

And then if we proceed further over,

5:11

we see the sublime tubercle

5:13

and more posteriorly the sublime ridge.

5:17

We can see that in this particular specimen,

5:20

I've labeled the tip the anterolateral facet,

5:23

the an medial facet.

5:25

We can see the radial notch that I talked about earlier,

5:29

and we can see the area of the sublime tubercle.

5:33

Now, there is a fracture classification based upon

5:38

this particular anatomy in the coronal plane,

5:42

A type one fracture where just a tip is involved

5:46

a type two fracture with three subtypes

5:50

that will become important a little bit later,

5:53

always involving the an medial facet in

5:56

A type three, which is a fracture further

5:59

away from the tip.

6:01

So this is a fracture classification in the coronal plane.

6:07

The third anatomic consideration is in fact that

6:11

although the radial humeral joint is of lesser importance,

6:15

the radial head becomes a critical stabilizer

6:19

to valgus stress when something is wrong on the medial side.

6:24

And the something that may be wrong,

6:26

in fact could be a fracture

6:27

or could be disruption of one of the medial ligaments.

6:34

The fourth anatomic consideration is that

6:39

the most important ligament stabilizers are the anterior

6:43

bundle, or it's two bands of the medial collateral ligament

6:47

and the lateral ulnar collateral ligament.

6:49

That's not hard to understand.

6:51

You can see why if we get rid of the radial head,

6:55

this is a ring-like structure containing bone.

7:00

And then these two, uh, anterior bundle

7:03

and the lateral ulnar collateral ligament.