0:01

It just, I wanted you to be aware of all of these layers

0:03

because it's not uncommon

0:05

that we'll see some longitudinal striations in the bura.

0:08

This may be due to fibrosis and synovitis forming within it,

0:12

but I think it could also be

0:14

because the buri, once it forms, starts

0:16

to connect across those layers.

0:18

And you're gonna see some remnants of some of the fascia

0:22

and some of the muscular fibers

0:24

that crisscross in this area.

0:26

Most of the patients that we see

0:27

with pre patella bursitis have it due to mechanical reasons,

0:32

typically from repetitive overuse, repetitive friction.

0:36

Many of them may have occupational, uh, hazards

0:40

where they're working, uh, on their knees, uh, quite a bit.

0:43

So usually this is the history.

0:46

But there are other etiologies for pre patella bursitis

0:49

that we should be aware of, especially in the patients

0:52

that have more chronic bursitis as we see in this example

0:56

with wall thickening and, uh, synovitis within the bursa.

1:00

And some of the things that I like to consider, first

1:03

of all is I like to think about chronic infection.

1:07

I worry about gout, which happens to like this bursa.

1:10

And I always look carefully for a foreign body

1:12

because this is an area that is easily penetrated.

1:15

And then the patient may develop a walled off sterile

1:19

or infected, uh, bursal collection around the foreign body.

1:23

So, uh, do take a look when you see

1:25

something that looks chronic.

1:27

Uh, like this, this is an example of septic bursitis

1:31

and in this particular patient we have findings

1:34

that allow us to make the diagnosis readily.

1:37

We have wall thickening, of course that's not specific

1:40

because you could also see that in a gouty

1:43

or chronic bursitis for other reasons.

1:45

But we have a sinus track, which is a great finding

1:48

of an infection and a few bubbles of gas

1:51

that are visible on the x-ray,

1:53

though not appreciable on this particular MR section.

1:57

So those are the findings.

1:59

If I have a lot of wall enhancement edema

2:02

around the collection,

2:04

and these are much more specific, any bursal gas, a track,

2:08

any erosion in the underlying bone, it's wise

2:12

to just aspirate the fluid to make sure

2:14

that you're not dealing with the septic collection,

2:17

uh, in this area.

2:19

Now in terms of hemorrhage,

2:20

hemorrhagic bursitis is also not rare.

2:24

This is in the more chronic form here

2:26

where we have a nice wall around it.

2:29

We have multiple layers of blood product within the bursa.

2:34

Probably a more indolent, uh,

2:35

patient than in the example on the left.

2:38

This too is subacute blood products

2:40

'cause this is bright on a T one weighted image,

2:43

but this is less contained and it doesn't have a thick wall.

2:47

So I will just refer to this as pre patellar hemorrhage.

2:51

And I can tell you quite honestly, it is not easy

2:54

to distinguish a pre patellar hemorrhage

2:57

from the pre patellar

2:58

Morell lavalle lesion.

3:00

The pre patellar morel lavalle lesion also contains large

3:04

amounts of blood products.

3:06

This is created by dissection between the subcutaneous fat

3:11

and the underlying fascia.

3:13

And it's important to keep in mind

3:14

because next to the lateral thigh

3:19

around the greater trocanter,

3:21

this is the most common location.

3:23

So this is the second most frequent location for, uh,

3:26

pre patellar, uh, morel lavalle lesions.

3:30

Now, some of the findings that have been suggested

3:32

to help us to distinguish between these two entities are

3:36

that the collections tend to be large.

3:40

We can distinguish it from a pre patella bursitis

3:43

because the extensions will go past the midline

3:46

or the equator of the knee joint.

3:48

So it goes further peripherally.

3:50

The main feature that tells you that you're dealing

3:53

with a morel lavalle lesion on imaging is the presence

3:57

of foci of fat within it.

3:59

So these are considered islands of necrotic fat coming from

4:04

that separation between the subcutaneous fat

4:07

and fascial layer that are present within the collection.

4:11

The other feature is clinical, which is

4:14

that it does not resolve it follow up, uh,

4:16

imaging it often requires prolonged compression

4:19

to get these morel lavalle lesions to heal.

4:22

But there is overlap in the appearance of these

4:25

with a simple hemorrhage that is going to go on

4:28

and heal by itself.

4:31

I just wanted to show this, that you're aware of this.

4:33

You can sometimes get fibrosis in the pre

4:36

patellar soft tissues.

4:38

Uh, this is a nice example of thickening

4:40

of the superficial fascia.

4:42

And this was in a patient who is a bicyclist.

4:45

So this particular entity can be due

4:48

to occupational reasons,

4:50

but it is recognized as a cause

4:53

of pain in elite cyclists.

4:55

Probably the repetitive flexion

4:57

and extension of the patella against the fascia

5:00

results in thickening.

5:01

And it can be symptomatic enough to require

5:04

that this tissue be excised.

5:06

And we can recognize that this is a superficial fascia

5:09

because it's very extensive.

5:10

It goes well above the knee joint

5:13

and then it also continues laterally

5:15

and medially overlying the muscles

5:18

and reticulum corresponding to the expected position

5:22

of the superficial fascia.

5:24

So be aware of this, um,

5:26

and that it can, uh, become symptomatic

5:29

and usually there's not a lot of fluid, uh, around it.

5:32

It's just a, uh, a thickened fibrotic band of tissue.