0:00

This is a 32-year-old man with ankle pain

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and subtalar tenderness, and yes, he is 32.

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Let's do what I would normally do and scroll the

0:11

sagittal projection, the lateral radiographic

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view, if you will, and start looking for

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hotspots with their correlate on the T1.

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And, and right away, it's obvious that there's

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some edema and swelling and a very unusual

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look to the posterior ankle, specifically

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the os trigonum, which should, should be

0:30

a small, round, ossicle-like structure.

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So that's problem number one.

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While we're scrolling, let's point

0:37

out a bunch of other findings,

0:39

because we're case reading together.

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There's fluid in the FHL, or

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flexor hallucis longus, sheath.

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That should, shouldn't be there, but that sheath

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normally communicates with the ankle joint.

0:52

So it's an outlet valve telling you

0:53

that there's an ankle effusion that's

0:55

dissected up there, and I've seen people

0:58

remove these incorrectly as ganglia.

1:01

We have also identified another bone fragment,

1:04

and perhaps even a third one on our T1

1:07

weighted image, which is where bone fragments

1:10

are most easily identified between these

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two series, although the other series that

1:16

helps you see intra-articular, intra-versal,

1:19

capsular fragments is the gradient echo.

1:21

Not shown at this time.

1:24

Let's keep looking.

1:25

We've got a little, teeny, small

1:26

Achilles distally, but it's intact.

1:30

The shape of the calcaneus, pretty good.

1:33

The subtalar articulation, pretty good.

1:39

The ankle articulation.

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Well, it's a little offset with an

1:43

effusion, but otherwise, pretty good.

1:47

I am struck by the lack of muscles

1:50

in the midfoot and forefoot.

1:52

So I am wondering whether this patient is not

1:55

using the foot due to hindfoot pain, Or the

1:58

patient is a diabetic at age 32, unrecognized

2:02

and unreported, with amyotrophy, or third,

2:06

there's some type of neurologic problem.

2:08

But let's set that aside for now.

2:11

Let's keep looking, because

2:12

we've got another hot spot.

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Right smack dab in the center of the

2:17

talus and sinus, tarsi, and canal.

2:20

And it looks very messy in there.

2:23

So that's another area that

2:24

we're going to have to deal with.

2:26

So, right off the get-go, I'm thinking

2:28

Posterior Impingement Syndrome

2:31

and possibly Sinus Tarsi Syndrome.

2:36

Let's talk briefly about Posterior Impingement

2:38

Syndrome, which we've done in another vignette.

2:40

We said the most common cause is a

2:42

weird, overgrown, misshapen os trigonum.

2:46

This patient has it.

2:48

Synovitic proliferation.

2:49

This patient has it.

2:50

Erosions in the talus underneath,

2:53

deep to the os trigonum.

2:54

This patient has it.

2:56

Fractured Stieda process.

2:58

Patient doesn't have it.

3:00

Intra-articular bodies or posterior

3:03

recess bodies, this patient has it.

3:06

Deformity of the calcaneus, protruding

3:09

upward to encroach on the retro-tailer

3:12

space, this patient doesn't have it.

3:15

Encroachment of the tibia on down with a hook

3:19

in the same space, this patient doesn't have it.

3:24

But clearly, we have evidence of

3:27

posterior impingement syndrome.

3:29

Oh, but there's more.

3:31

We're not done yet.

3:32

What are we going to do with these large,

3:34

giant pseudocysts and areas of erosive

3:38

change that have affected the talus

3:42

coming from the sinus, tarsae, and canal?

3:46

I will give you the fact that there's

3:48

a little bit of swelling and edema and

3:50

some erosive change in the posterior

3:52

facet, but I'm going to focus right here.

3:55

So, I'm going to start in the medial aspect

3:57

of the sinus, Canal, which is medial, and the

4:02

sinus tarsi, which opens up as I scroll lateral.

4:07

So this is really important because I

4:09

have identified an important ligament,

4:12

the talocalcaneal interosseous ligament.

4:17

Let's keep going, because the next ligament

4:19

I want to see is the cervical ligament.

4:22

It should be a thicker, but

4:24

blacker, straight structure.

4:27

It is thicker, alright, too thick.

4:30

Blacker or black?

4:31

It's not black, it's gray.

4:33

Alright.

4:34

It's so gray, I can't even see

4:36

it on the T1-weighted image.

4:37

Let's keep going into the lateral retinaculum,

4:40

which is divided up into three bundles.

4:42

A medial, an intermediate, and a lateral.

4:46

And within this complex, the lateral bundle

4:50

and portions of the intermediate bundle are

4:52

known as the stem or frondiform ligament.

4:55

So we have another problem of major proportion

4:59

in the sinus, tarsae, and subtalar space.

5:02

So I suggest we go to a coronal.

5:07

I'm going to put up two coronals, nice and big,

5:12

so that you can see the anatomy quite easily.

5:16

And let's evaluate these ligaments, because

5:20

we have a nice landmark, sagittally,

5:23

to observe and cross-reference them.

5:26

Let me get my sagittal up here.

5:29

So let's go over to the talocalcaneal

5:31

interosseous ligament, right there.

5:35

And we see our obliquely oriented, from

5:38

proximal medial to infralateral, straight,

5:42

pretty thin, attached talocalcaneal

5:47

interosseous ligament in the sinus canal.

5:52

Let's go to the cervical

5:53

ligament, the next one over.

5:55

There it is.

5:57

It's too fat.

5:59

Its insertion, I'm gonna blow it up even bigger.

6:03

It's inserting, but its insertion is not normal.

6:06

Look at all these small cysts and areas

6:09

of fraying and complete graying out of the

6:13

cervical ligament as it attaches to the

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underbelly of the Ali with a huge pseudocyst.

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Let's keep going even more laterally to

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the regions of the medial, intermediate,

6:30

and lateral reticulum, also known as the

6:32

stem ligament or frondiform ligament.

6:34

I can't find them.

6:37

Instead, they were replaced by a morass

6:40

of bursal swelling, synovial hypertrophy,

6:44

and a pseudomass that prolapses

6:47

laterally and is sometimes misconstrued.

6:53

Let's look at our axial projection.

6:55

Let's take an axial.

6:56

Here's an axial T2.

6:59

Now perhaps this patient had

7:02

an ankle sprain or injury.

7:04

Because frequently these types of

7:06

abnormalities are associated with instability.

7:10

Especially the one in the sinus tarsi

7:12

canal called sinus tarsi syndrome.

7:16

They have inversion and

7:18

sometimes eversion injuries.

7:21

But the anterior talofibular ligament is present

7:25

and accounted for.

7:28

Oh, there's plenty of swelling and

7:29

irregularity in the back, where

7:31

we've got our posterior impingement.

7:33

Oh, there's plenty of swelling and irregularity

7:36

and an ill-defined character to the anatomy

7:38

in the sinus, tarsi, and canal space.

7:41

Here's the T1-weighted image.

7:42

I'm going to blow that up.

7:44

Look how much graying out you have

7:45

in the sinus, tarsi, and canal.

7:48

Let's go down to it.

7:49

Look at all this tissue here that

7:51

is kind of filling in that space.

7:54

And then the skeletal abnormalities are

7:56

appreciated in the back as described.

7:58

So, in summary then, what do we have, and

8:01

what are we going to say about this case?

8:04

Well, my conclusion would

8:05

read something like this.

8:07

Conclusion.

8:10

Findings consistent with Sinus

8:11

Tarsi Syndrome, including A.

8:14

Intact talocalcaneal IOL.

8:17

B.

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Injured cervical ligament.

8:21

C.

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Marked destruction or marked attenuation

8:27

with inflammatory reaction around the

8:30

lateral retinaculum, stem, and frondiform

8:32

ligament with extensive arthropathic

8:35

erosions, cysts, and pseudocysts.

8:39

Number two, signs of extensive posterior

8:44

impingement syndrome with a giant

8:47

ostrigonum further exacerbated by

8:49

posterior bodies and synovitic pseudomass.

8:53

Number three, unexplained midfoot

8:56

and forefoot massive muscular

8:59

atrophy to be further investigated.

9:01

The rest will stay within the body of the report.

9:05

Diagnosis

9:07

and main point of this case, sinus

9:09

tarsi syndrome with a little kicker,

9:11

posterior impingement syndrome.