0:00

So it's my privilege again to introduce another one

0:03

of our associates here.

0:05

All right. Uh, at U-C-S-D-A very important one

0:09

of our associates, Eric Chang.

0:11

Eric is, uh, an adjunct professor of radiology.

0:14

He spends most of his time at the VA Medical Center,

0:17

but we borrow him to come to the uc, uh, center as well.

0:22

He is a spectacular radiologist, not just in clinical

0:26

and teaching abilities,

0:27

but he is one of our most important, uh, researchers.

0:30

And because of that and

0:32

because of the impact

0:33

that he's had on musculoskeletal imaging worldwide, he

0:37

recently received the President's medal

0:39

of the International Skeletal Society.

0:42

So it's a privilege, Eric, to have you here.

0:45

I know you're very good with workstations,

0:47

so I don't worry about that.

0:49

And, uh, thank you a lot for participating in this course.

0:52

You're gonna show us some cases

0:54

and then hopefully we'll have a little bit of time for

0:57

questions and answers.

0:59

Thanks for the introduction and the invitation.

1:03

We're gonna try to move quickly 'cause I have a lot of cases

1:05

and I'm gonna, uh, only have 25 uh, minutes.

1:08

Lemme start my timer.

1:09

Uh, the first case is a 58-year-old

1:11

woman with left knee pain.

1:13

Uh, the MRI was done two months after the pain began.

1:16

And so for, uh, mr

1:21

of the knee, I usually start in the sagittal plane

1:24

and try to make some findings

1:25

and correlate with the other, uh, planes.

1:28

But here, starting on the sagittal plane, you can see that,

1:31

um, this female there, there's a large body habitus.

1:34

There's several slices you gotta get through to get

1:36

through the subcutaneous, um, tissues.

1:40

And you see that there's, right off the bat, uh,

1:42

a tremendous amount of edema.

1:44

Uh, this edema surrounds these medial supporting structures,

1:48

and there's the medial meniscus.

1:51

And when we see the medial tibial plateau, you can see

1:53

that there's this, uh, pronounced bone marrow edema.

1:57

You can actually see that there's this hypo intense line

2:00

that is parallel and,

2:01

and right up against the subc chondral bone plate.

2:03

And this is the appearance of an insufficiency fracture,

2:07

and often the bone marrow edema companies that.

2:11

And, um, as we keep scrolling, uh, from medial to lateral,

2:15

you start seeing some increased signal in this posterior

2:17

horn of the medial meniscus

2:19

and what we would call a ghost meniscus sign, uh,

2:23

as we approach the root.

2:24

And so if we correlate this with the, uh, coronal image,

2:27

you can see that we're slicing right through that gap.

2:30

And so this is a complete tear of the posterior root

2:34

of the medial meniscus with an insufficiency fracture.

2:38

As we keep going lateral, you see the, uh, the PCL,

2:42

the ACL and the posterior root of the lateral meniscus.

2:46

We're, we're gonna have some cases discussing this in more

2:48

detail, but this posterior root

2:50

of the meniscus is abnormal in appearance.

2:53

Um, there's, uh, increased signal intensity.

2:55

There's, there's short fibers, there's long fibers.

2:57

And both of these, um, components of this posterior root

3:00

of the lateral meniscus are abnormal.

3:03

Uh, so to me, I called, um, a low grade tear

3:05

of this posterior root of the lateral meniscus.

3:09

And there's even some signal in the, uh,

3:11

posterior horn of the lateral meniscus.

3:14

On the coronal, you can see that the body

3:17

of the medial meniscus is extruded.

3:19

And there's this small erosion at the periphery

3:22

of the medial tibial plateau.

3:24

And the meniscal tibial ligament here, uh, also, uh,

3:27

has high signal intensity and, and appears disrupted.

3:35

And so at arthroscopy, uh, this is the, um, the, uh,

3:39

the standard views from these anterior portals.

3:41

This is the medial fem condyle, which corresponds to this,

3:44

um, on the MRI.

3:45

This is the body of the medial meniscus.

3:47

The posterior horn of the medial meniscus.

3:50

And you can see the stump of the torn, um, posterior root

3:54

of the medial meniscus.

3:55

This, uh, is the same as this structure with synovitis, um,

3:59

as, as nicely shown on the arthroscopy.

4:02

And they did a transtibial pullout repair,

4:05

and that was fixed with three sutures.

4:08

Uh, many of these, uh, risk factors

4:10

and associations were seen in our case, uh, the,

4:13

the female sex increasing age, high body mass index.

4:16

And, um, more recently, um, we

4:20

now know that the classic thinking where you think that, uh,

4:24

meniscal extrusion was a result of the root tear.

4:27

Um, in the last handful of years, um, the Mayo Group,

4:31

the Mayo Orthopedics Group, uh, has shown that, um,

4:35

all patients that demonstrated meniscal tibial ligament

4:38

disruption and associated meniscal extrusion, um, they, uh,

4:42

they had these findings

4:44

before the actual development

4:45

of the medial meniscus root tears.

4:46

But when they present for imaging,

4:48

what we typically see is the root tear,

4:50

the meniscul tibial li, um, ligament injury

4:52

and the extrusion altogether, uh, very often accompanied by

4:55

that insufficiency fracture.

4:57

Uh, I had called a partial tear of this posterior root

5:01

of the lateral meniscus.

5:02

Um, but it's hard to know if I'm right.

5:04

Uh, it doesn't look normal, even in retrospect to me.

5:06

But the surgeon did, uh, probe this area

5:09

and said that it was intact.

5:11

Um, admittedly, I, I spoke

5:13

to the surgeon in depth about this

5:15

and we reviewed, um, images and,

5:17

and it's hard to fully evaluate, uh, the posterior

5:19

of the lateral meniscus when there's, um,

5:21

unless there's a, a very obvious abnormality.