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Let's start with PLRI.

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The typical mechanism for this injury,

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which can result in an elbow dislocation

0:10

without a fracture is a fall on outstretched hand.

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As shown here. Three major forces relate

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to this mechanism of injury.

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The first one easy to understand is axial compression shown

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by that blue arrow at the bottom.

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Okay, that would be the first of these.

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The second would be bending or valgus force.

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And you can see by the orange, uh, double-headed arrows

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that occurs at the level of the wrist, at the level

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of the elbow, at the level of the shoulder,

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worse at the level of the shoulder,

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but certainly moderate at the level of the elbow.

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And then the third force is a rotational force or torsion

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because the body falls over

0:58

that fixed uh, arm.

1:01

And this relates or produces supination of the forearm.

1:05

So those are the forces that are involved.

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Now, there are some clinical tests that can be used for this

1:12

axial compression with supination valgus stress.

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This could be done in a single position

1:18

or with various degrees of elbow flexion and extension.

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With conventional radiography, you may not see anything,

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but if you're dealing with a fairly severe PLRI,

1:31

you may see a fracture back here created

1:36

during a dislocation in which the radial head impacted

1:41

the posterior aspect of the Capella.

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More about that in a few minutes.

1:47

The abnormality that occurs

1:50

with PLRI involves the horri circle

1:54

about the elbow.

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The abnormalities are staged as shown here

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with three stages beginning laterally,

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and then extending both posteriorly

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and anteriorally to the medial aspect of the elbow joint.

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With these stages, more and more rotation

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and eventually dislocation occurs.

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So let's look at this

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and note with the drawing,

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this results in external rotation of the forearm.

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The stage one injury is an injury leading to tearing of

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that lateral ulnar collateral ligament shown here

2:34

with a picture of the lateral side.

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You may see minor asymmetry on a radiograph, particularly

2:40

with stress radiography,

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but the radiograph may look surprisingly normal.

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Here's an example of what would be a stage one.

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We've disrupted the lateral ulnar collateral ligament.

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You can see that in the middle here, there's actually a bone

2:58

Abnormality as well.

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This finding alone

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with normal medial ligaments would make this

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as stage one compatible with stage one

3:08

PLRI.

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The stage two injury results in a perched position

3:15

with further external of the forearm.

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Now, as we look at the lateral side to disruption

3:23

of the lateral ulnar co collateral ligament,

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we've added disruption of the radial collateral ligament

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and the capsule begins to tear extending laterally to mely,

3:36

both anteriorly and posteriorly.

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For stage three, there are two subgroups.

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Stage three A can be a dislocation

3:49

of the elbow joint.

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As we look at it, we can see here

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that the capsule we're looking at the medial side.

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So the capsular tearing has extended anteriorly

3:59

and posterior to the medial side,

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and the first ligament that tears is that posterior bundle

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of the medial collateral ligament and ni.

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And finally, with stage three B

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and a dislocation,

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what you will see on the medial side will be also disruption

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of the anterior bundle of the medial collateral ligament.

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So the problems began laterally

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and then involved the medial structures extending from the

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lateral to the medial side, both anteriorly and posteriorly.

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And with a full dislocation, the stage three injury

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that radial head may have contacted the posterior aspect

4:44

of the Capella.

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You may see that on an MR as a bone contusion

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or a fracture sometimes with the bone fragment

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as shown on the picture on your right, this is known

4:57

as the Osborne Cordal lesion.

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It is a very important finding.

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The fracture you can see even with radiographs,

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but you see the findings better with CT or mr.

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If you see this, you're probably dealing with postal lateral

5:15

rotary instability as the cause of the elbow dislocation.

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Now, you don't have to have this fracture.

5:22

So PLRI can produce an elbow dislocation without

5:27

any fracture differing from the fractured dislocations I

5:32

talked about earlier.

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So here's an example of a stage three B elbow dislocation,

5:39

PLRI mechanism.

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You can see there's extensive disruption

5:44

of the medial collateral ligament.

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We're showing you disruption here of the anterior bundle.

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There's all kinds of disorganization, both of tendons

5:54

and ligaments on the lateral side.

5:56

This is PLRI. Here's another example.

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Look at this. These are injuries widespread involving

6:05

tendons and ligaments, both sides of the elbow,

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but there's not a significant fracture.

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Now I know this particular, uh, person, he is a good friend

6:15

of mine, and the mechanism of his injury

6:18

was a little bit unusual.

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He was visiting an ostrich farm

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and they, there was one big ostrich

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and there was a fenced area,

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but his kids stayed outside of the fence.

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He went in, he loves to take photographs,

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and so he began photographing this particular ostrich

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as kids threw some stones at the ostrich.

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The ostrich turned toward my friend inside the cage.

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This was the next picture he took

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as the ostrich charge toward him.

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And then after that, he took one final picture like this.

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And you can see what happened to him among the injuries

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included an elbow dislocation.

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I'm not sure how he punished the kids after this,

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but he was a bit angry about this encounter.

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Now, there are some who believe

7:15

that you can have a valgus injury

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that will result in an elbow dislocation

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without a fracture.

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Here's an examples taken from the literature of what

7:27

that might look like in a football player,

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what it might look like through a diagram.

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And this has raised, or this diagnosis is raised.

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When you see examples like this one

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where there's been an elbow dislocation

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that's been documented

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and that the major abnormalities around the medial side here

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with complete tearing

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and the abnormalities on the lateral side are minor

7:54

because that does not go along with the mechanism

7:58

of PLRI.