0:00

So next we're gonna be talking about some companion cases

0:04

related to the TRO caners.

0:06

So the question here is

0:07

what is unusual about these quote unquote

0:10

evulsion type injuries?

0:12

So if we look at case one, we see a fracture

0:16

through the lesser trocanter that is an area

0:19

of attachment of a tendon.

0:22

So the ilio sous tendon, uh, one of the main hip flexors

0:26

attaches to this region here.

0:28

So this is an enthesis, meaning a tendon bone junction.

0:31

And we can see that there's a fracture

0:33

with a displacement of the bony fragment.

0:36

Compare it to case two where we see a fracture line

0:40

for the greater trochanter.

0:42

This is an area where the hip abductors attach to.

0:46

So those abductors, like the gluteus minimus

0:50

and gluteus medias are similar to the rotator cuff

0:54

of the shoulder in that they help with hip abduction.

0:58

And so this is an attachment site for those tendons.

1:01

So again, another enthesis of tendon bone junction.

1:04

And these are both fractures

1:05

that you may encounter in the emergency department.

1:09

So when we talk about uls of injuries,

1:11

and there are numerous ones about the pelvis, it's related

1:14

to a sudden or chronic forces that are applied at the origin

1:18

or insertion of a muscle or a group of muscles

1:20

or basically a mu a tendon attachment

1:23

in a younger age group pediatrics

1:26

where they're not fully developed yet,

1:28

it could be related to the physes.

1:30

And so there are a number of physes around the pelvis.

1:33

They assist in completing growth,

1:35

but they also serve the other secondary function

1:38

as an enthesis, meaning the tendon bone junction

1:40

where the muscles can then attach to the bony structures

1:44

and allow them to perform their function.

1:47

And when you're dealing with adolescents,

1:48

that is the weakest part of the skeleton is

1:50

through the cartilage growth plate.

1:53

And so just to understand these lesions, uh,

1:56

as they do present in adults, these are the main areas

2:01

of physes about the pelvis.

2:05

So again, starting from the top down in the iliac crest,

2:09

you have areas of the abdominal muscles.

2:12

And here along the uh, iliac crest,

2:15

you can get forceful contractions of the abdominal muscles

2:18

may occur with running, jumping figure skating.

2:22

Next is the anterior superior iliac spine.

2:26

So the anterior superior a spine is at this

2:29

lower outer portion of the iliac wing.

2:32

It's the attachment of the sartorious muscle

2:35

and the tensor fascia latte.

2:38

At the A SIS you can get evulsion injuries often related

2:42

to things like American football, baseball, sprinting,

2:45

biking track.

2:47

As we move a little bit down, we have the A IIS

2:51

or anterior inferior iliac spine.

2:54

And at this attachment site you have the rectus fem.

2:59

So the rectus fous origin direct head comes off

3:03

of the A IIS

3:04

and you can have evulsion injuries here related

3:07

to things like soccer, field hockey

3:10

and other, uh, running injuries.

3:13

So now if we move medially toward the pubic synthesis,

3:18

so at the body of the pubis

3:20

and the inferior pubic ramus, we have attachments

3:23

of the adductors, so adductor longus and magnus

3:27

and brevis as well as the gracilis.

3:30

And you can get evulsion injuries there.

3:33

And then moving down toward the bottom on the sits bones

3:36

where we have our ischial tuberosity, uh, that's

3:39

where the hamstrings attach a very powerful muscle group

3:43

and can have hamstring avulsion injuries there.

3:46

And that may occur with a variety of sports such

3:49

as baseball skating, ice hockey, track or football.

3:53

And then what we're left with are the two tro caners,

3:57

so the greater trochanter where you have the hip rotators,

4:00

the abductor, and the lesser trochanter

4:02

where you have the ilio sous attachment.

4:05

So here are some examples

4:07

of other avulsions in this case here.

4:10

If we look carefully in this person with left-sided hip pain

4:14

after an event, we can see a small bony fragment

4:18

that's come off of the anterior superior iliac spine.

4:22

So that's a sartorious evulsion of the A SIS.

4:26

And here's a case of a chronic one.

4:29

So sometimes when these avulsions occur, the bone may not be

4:34

that distracted or you may get bony proliferation.

4:37

So you kind of get this zaphy

4:39

or spur that occurs at the attachment site

4:42

and that may occur from either chronic tugging

4:45

or may have been after a single event where the bone tried

4:48

to heal and remodel along that area.

4:51

So this is a chronic condition in this person

4:53

where we can see the bony remodeling but still symptomatic

4:57

and active as on the MRI.

4:58

There is edema

5:00

and soft tissue signal surrounding that.

5:05

Here's an example of an issue tuberosity of uls

5:08

in the chronic condition where we see now

5:10

that there has been a bony fragment

5:13

and it's separated from the parent shield tuberosity,

5:17

the underlying ischial tuberosity is remodeled.

5:19

There's additional foci of heterotopic ossification

5:23

that formed in addition

5:24

to probably some growth of that fragment.

5:27

But that's a chronic situation of the hamstring evulsion.

5:31

Now they don't have to become that displaced.

5:34

And so when that occurs, you can get this bony

5:38

proliferation and remodeling as we see on the right here.

5:42

And here it is on the frog leg projection

5:45

and it almost has this kind

5:46

of tumor effect quality to it or features.

5:50

So sometimes gets mistaken for bone tumors,

5:53

but realize that there are many, many attachments around

5:57

the pelvis and it's much more common to get kind of a,

5:59

a versive or tug lesion rather than neoplasm.

6:04

And this has the features that goes with a benign entity,

6:08

meaning the zonal pattern of the mineralization is that it's

6:13

got a cortex and it has medullary components centrally.

6:18

And it's at a common site where we have an attachment

6:20

and no, no other aggressive features identified here.

6:24

And so that's our chronic ischial tuberosity avulsion

6:27

showing bony proliferation

6:29

and potentially mimicking a neoplasm

6:33

here a CT was done.

6:35

And what the CT demonstrates on these numerous slices is

6:39

that this abnormality is made up of mature bone.

6:42

It has a outer cortex, inner medullary portion

6:47

and not representing mineralized matrix of a neoplasm.

6:52

So now if we go back to our cases

6:55

that we originally started the segment with

6:58

here in case one there is a lesser trocanter evulsion

7:03

and on the frontal projection there is this

7:05

displaced bone fragment.

7:07

But now that I've provided the frog leg projection,

7:11

if you look carefully, you'll see

7:13

that there is also some other underlying process here

7:17

that makes this a bit more sinister.

7:19

And so in the region of the lesser TRO anter,

7:22

we see this moth eaten pattern of primitive bone lesion

7:27

representing, uh, area of bone destruction.

7:30

And on MRI, within that area, there is this

7:35

T two hyperintense lesion that's replacing the bone

7:38

that's got some surrounding, uh, per lesional edema

7:41

and allowed that fragment to basically, uh,

7:44

pop off at the tendon attachment.

7:46

So this was a metastatic neoplasm to the area

7:51

of the lesser trocanter.

7:54

Now comparing this to our case number two,

7:56

so in case number two,

7:58

again showing you on the frontal projection fracture

8:01

through the greater trocanter here

8:04

and on, uh, example of MRI showing

8:08

that there is basically a fracture line in that area,

8:12

but no infiltration of the bone marrow or other deposits,

8:16

and basically a TRO enteric fragment at the

8:20

abductor attachment site.

8:23

So while you may put this in the spectrum of evulsion

8:27

type injuries, because there are big tendon attachments

8:31

there, they are typically not related to evulsion lesions.

8:36

With regards to the lesser trocanter,

8:39

it is usually not something

8:40

that uls is on its own despite having the ilio sous tendon,

8:43

a big muscle attaching there

8:46

and typically relates to some other underlying process.

8:50

So particularly in elderly individuals, uh,

8:53

lesser trocanter evulsion

8:55

Should be considered potentially representing a neoplastic

8:58

process until proven otherwise.

9:00

That is with an MRI, whereas in the greater trochanter,

9:04

while it is at a tendon attachment site,

9:07

it's usually related to a fall and not necessarily a tug.

9:11

And so it's really not a true phenomena.

9:14

You can have avulsions of the abductor tendons,

9:19

typically gluteus minimus or gluteus medias.

9:22

And that gluteus medias avulsion usually results

9:25

as a soft tissue injury at the enthesis.

9:27

So the trochanter is pretty robust bone

9:31

and typically not a vols as a bony fragment,

9:35

but it's more of a tendon avulsion on the soft tissue side.

9:38

And it may have a very small osseous component,

9:41

but when you fall on the side of your hip, you can imagine

9:45

that the trocanter is gonna be one of the main structures

9:48

that primarily hits the ground,

9:50

and that's why it's susceptible to that kind of injury

9:53

and not an evulsion per se.