0:00

Now with that as a review of the anatomy, it's time

0:03

to turn to injury patterns.

0:08

We've already talked in detail about straight

0:10

and rotational instabilities of the knee,

0:14

and I showed you a chart much like this one.

0:16

Okay, this one's a little bit smaller,

0:19

but I wanted to point out,

0:20

as we look at the various motions in the first column

0:24

and the primary restraints

0:25

and secondary restraints in the second

0:27

and third column, I wanted to out outline

0:29

where you can find the medial collateral ligament.

0:33

So you can see there are a lot of abnormal motions

0:36

that might take place in the knee

0:38

where there could be an injury

0:40

to the medial supporting structures.

0:43

All right, the major one,

0:44

however, of all of these is valgus.

0:47

So I'm gonna stress a valgus force

0:50

or a valgus injury to the knee.

0:54

I showed you this particular picture in one

0:56

of my earlier lectures when I pointed out

0:59

that when you have a valgus injury of the knee, the point

1:03

of contact shifts to the lateral compartment.

1:06

You remember that? And I said that in

1:08

that particular region we have abnormal compression,

1:11

and that compression can lead to fractures

1:14

or bone contusions.

1:15

Here a fracture can lead, lead to meniscal pathology,

1:20

not in this particular case.

1:23

And I mentioned that everything medial to the point

1:26

of contact is under increased tensile force.

1:30

The medial supporting structures have the longest moment arm

1:34

and hence are the primary restraints.

1:37

So typically they are injured first

1:40

when there is a valgus four supplied to the knee.

1:44

We also can have injuries to the cruciate ligaments.

1:47

They work over a shorter moment on.

1:50

And in this particular case, as I mentioned

1:52

before, there was an injury

1:54

to the anterior cruciate ligament,

1:57

so a typical valgus injury.

2:00

Now, in many of these injuries,

2:01

there's an external blow applied to the lateral aspect

2:05

of the knee, and you can see

2:07

by my green arrows in these images,

2:10

that external blow can occur at various

2:13

locations along the lateral aspect of the knee.

2:16

Sometimes you can figure out the vector, depending upon

2:21

where the edema is.

2:23

Does the edema involve just the anterior third,

2:26

the middle third, or the posterior third?

2:28

In this particular case, all thirds are affected,

2:33

all the supporting structures are affected.

2:36

So probable vector of this external force shown

2:39

by the green arrow, I'll show you a typical example

2:44

of a valgus injury to the knee.

2:46

Again, I'm showing you images from a patient

2:49

with an accurate history,

2:51

and I'm showing you an image taken from the

2:54

internet on the left.

2:55

This was a 22-year-old female

2:59

Soccer player who was kicked in the outer aspect

3:03

of the knee during a game.

3:05

I'm showing you here this marrow change,

3:08

which looks like a bone contusion, not a fracture,

3:12

indicating the external blow.

3:14

And here I'm showing you the typical pattern of injury

3:17

that you could see in the medial supporting structures,

3:21

this injury involving mainly the tibial collateral ligament,

3:25

but perhaps the deep medial meniscal femoral capsular

3:29

ligament as well.