0:01

So let's go to the more distal iliotibial band.

0:04

And on occasion, usually with more high energy traumas,

0:07

either MVAs

0:08

or falls from significant height,

0:10

not usually seen in sports injuries.

0:11

You may encounter a bony avulsion of gertie's tubercle.

0:15

And here's one such example.

0:16

You can see that anterolateral tubercle

0:18

of volt from the bone.

0:20

And it's important to know that isolated injury

0:23

to this is very uncommon.

0:24

This is usually associated with cruciate ligament injury

0:28

and again, more often in the setting of high energy trauma.

0:33

Here's an example of a gerie tubercle avulsion.

0:36

This obviously on ct,

0:38

but you can see the donor defect site along the

0:40

anterolateral tibia and displaced posteriorly and laterally.

0:44

And there's the corresponding radiograph.

0:46

Obviously there's a lot more going on here than just the

0:49

gerdy tubercle avulsion.

0:50

We have the proximal fibular fracture.

0:52

We also have bone fragments near the intercondylar eminence,

0:55

so we have to worry about those con concomitant ACL

1:00

or PCL injuries.

1:02

And here's the corresponding MRII think, uh,

1:05

we'd have no problem diagnosing a grade 3M CL injury.

1:08

The meniscal tibial portion of the MCL is torn.

1:11

We can't even really see the superficial portion.

1:13

And here on the lateral side, we can see the all tibial band

1:17

and this avulsion fracture of gertie's tubercle

1:20

and not really shown completely,

1:22

but we can see part

1:24

of an intercondylar emin avulsion fracture.

1:30

So that brings us more posteriorly to the sigon fracture

1:34

that we're all taught in training to look carefully

1:37

for on our knee radiographs, and this can be quite subtle,

1:40

but we try to look for this vertical bone fragment,

1:43

usually about five to 10 millimeters in length

1:46

and just below the level of the lateral tipi plateau.

1:49

And as we are all taught that this is highly associated

1:52

with anterior cruciate ligament injuries

1:54

and a specific pattern of instability, knee known as ery.

2:00

Now here's the corresponding MRI In the same patient.

2:03

We can note the bone edema that we might see with ACL tears,

2:07

but if you're not paying close attention,

2:09

you might miss out on seeing

2:11

that there is focal cortical disruption here.

2:13

That's definitely easier to pick up on the radiograph.

2:16

So make sure you look at this closely.

2:19

Here's just another more obvious example

2:22

of a sigon fracture, at least on MRI.

2:25

You can see the elevated cortical bone fragment,

2:27

but you notice that the edema is all not

2:30

as pronounced as the last case.

2:31

And sometimes avulsion fractures as compared to compressive

2:37

injuries or osteochondral fractures can produce little

2:40

to no bone marrow edema at the area of injury.

2:43

So you really gotta pay close attention

2:45

to these sigon fractures.

2:47

I'll give you a sneak preview of what's to come.

2:49

This is another structure.

2:51

This is that antral lateral ligament

2:53

or mid third lateral capsular ligament.

2:55

And this is indeed what results in these

2:57

sigon fractures originally

2:59

Described by Paul Sigon.

3:00

And of course, here's the corresponding tear

3:03

of the anate ligament.

3:06

So here's just another example of a sigon fracture on ct.

3:10

Obviously more clearly delineated on x-ray based modalities,

3:13

but we can pick it up on MRI again, we did do a study, um,

3:18

almost 10 years ago now looking at what exactly

3:22

resulted in the sigon fracture

3:24

and classically what has been described

3:26

and what we found most frequent in over half of cases

3:29

that indeed it's this mid third lateral capsular

3:31

ligament or a LL.

3:33

But we did find in a smaller number of patients that

3:36

portions of the posterior aspect

3:38

of Tial band did also contribute to the development

3:42

of sigon fractures.

3:45

If you go back to that original paper by the Antola Complex

3:49

Consensus Group, they basically said,

3:52

we really don't have any idea

3:53

what exactly causes the sigon fracture

3:56

after reviewing the literature extensively,

3:59

and it remains unclear.

4:00

They, they noticed that, uh,

4:02

some papers talked about the a LL.

4:04

Some people, uh, talked about the deep IT band

4:06

and even some talked about, um, portions of the biceps

4:10

or biceps femoris, a neurosis, those anterior tibial arms,

4:14

uh, could contribute to the, uh, second fracture.