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Hello and welcome to Noon Conference,

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hosted by M R I Online Noon Conference connects the global radiology community

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through free live educational webinars that are accessible for all.

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And as an opportunity to learn alongside top radiologists from around the world,

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You can also sign up for a free trial of our premium membership to get access to

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hundreds of case-based micro-learning courses across all key radiology

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subspecialties. Today we are honored to welcome Dr.

0:39

Stephen j Pran for a lecture on wrist M r I. Dr.

0:43

Pomerantz is the c e o and Medical Director of ProScan Imaging,

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chair of Naples, Florida Community Hospital Network,

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and the founder of M R I Online.

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He's authored numerous medical textbooks and M R I, including the M R I,

0:57

total Body Atlas. Dr. Pran is also an AVID conference,

1:01

lecturer and chairs. This the fellowship training program in MR.

1:05

And Advanced Imaging.

1:06

We're thrilled he's here today to share his expertise with us.

1:10

At the end of the lecture, please join Dr.

1:12

Pran in a q and a session where he will address questions you may have on

1:16

today's topic.

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Please remember to use the q and a feature to submit your questions so we can

1:21

get to as many as we can before our time is up. With that,

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we are ready to begin today's lecture. Dr. Pomerance, please take it from here.

1:29

Okay, great. Good afternoon, everyone. Good morning everyone.

1:34

Wherever you are in the world, we're talking about wrist, M r I,

1:38

which is a complex subject. The further away you get from the trunk,

1:42

the more detailed the anatomy, but,

1:44

but it is a joint unlike the ball and valve joints. That makes some sense.

1:48

So it's not quite as difficult that as it appears to be.

1:53

And I'm going to focus on, uh, a few issues. But before I do,

1:57

I wanna remind you that on September 10th through 14th, Dr.

2:02

Don Resnick, uh, will be presenting a course on the upper extremities,

2:06

uh, along with Megan Mills and Christine Chung for the hand, wrist, and fingers.

2:10

And I will be doing the case reviews in between the lectures.

2:16

Uh, the lectures will be interactive.

2:18

There'll be case reviews that are scrolled, uh,

2:21

approximately three hour sessions each day.

2:24

And we're gonna be focused on the shoulder, the elbow, the hand and wrist,

2:26

the fingers, and entrapment neuropathy. So, uh,

2:30

hopefully you'll tune in and get some of your pressing questions regarding, uh,

2:35

the upper extremity, uh, in front of us.

2:39

So what we cover in this lecture is technique and anatomy,

2:43

the triangular fibrocartilage, ulnar variants, simple carpal instability,

2:47

complex carpal instability,

2:50

and slack and snack wrist.

2:53

We're not gonna spend a lot of time on, uh, uh, things like, uh,

2:58

masses and soft tissue lesions and arties since we're we're time

3:03

constrained. Uh, let's start out with technique. And,

3:08

um,

3:09

I am showing you on the right a rigid wrist coil with the arm at the side.

3:14

I typically like to have the arm a little bit closer to the body. Uh,

3:19

I scan my patients with either the thumb up in the neutral position or in

3:23

pronation. Uh, most people cannot hold still in supination.

3:27

And the goal is to get something, you know, like this,

3:30

which is a high resolution image, two millimeter slice, thickness high matrix,

3:36

and you can even see the, the trabecula of the bone,

3:40

the triangular fibrocartilage with its radial and peripheral and distal

3:44

attachments. But I'm showing it for the anatomic detail, uh,

3:48

which is greatly influenced by the field of view and the wrist.

3:51

I don't like to have fields of view of greater than 12, uh,

3:55

on the average with a, with a high quality instrument.

3:58

I like my fields of view to be around eight, maybe nine,

4:01

and that one was about seven or eight. Here's a patient, uh,

4:05

with the arm at the side, another rigid, uh, wrist coil.

4:09

This time the the hand is in pronation and we're asking 'em to perform a

4:13

clenched fist view to look at the ulnar variants. More on that in a few moments.

4:17

Here's another, uh, rigid coil with the thumb up in the neutral position.

4:22

Now, as far as the sequences go, this applies across the board.

4:26

T one is used for bone marrow in any, in any body part. Uh,

4:30

we'll use gradient echo, either two D or three D uh,

4:35

for intraarticular assessment, the capsule and the cartilage.

4:39

And there are some fancy new gradient,

4:41

echo sequences known as adage from Hitachi,

4:44

merged from GE Merge Fast Field Echo from Phillips and Medic from

4:49

Siemens,

4:50

along with a related sequence called steady state free pre procession or fiesta

4:55

from General Electric that are used in the risk to get an art arthro graphic and

5:00

joint effect at high field.

5:05

I personally like the proton density, uh,

5:08

tally sensitive inversion recovery over the T two fat suppression.

5:12

Some of my colleagues on the west coast prefer the T two fat suppression, but I,

5:17

I feel like I get a little more signal, a little more pop with,

5:20

with this sequence. That's not to say I don't have a T two, uh,

5:23

but I always have this as part of my workhorse sequence for any joint

5:28

at low field. I'll use short time inversion recovery or stir,

5:32

and then I'll use T two to characterize, uh, tendon injuries and to date them.

5:37

When I say data, I mean acute, subacute, chronic, remote, and so on.

5:41

So when I start out,

5:43

I put up my coronal sequences first because I'm most comfortable there,

5:46

you know, from, from doing radiography for so many years. Uh,

5:51

I'll put up, say the T one, the gradient echo,

5:53

the T two and the proton density spur if I have all of them.

5:57

But I will initially focus on the heavily water weighted sequence,

6:00

the proton density, fat suppression,

6:02

looking for hotspots that makes it particularly easy and quick and expedient and

6:07

pragmatic to interpret. So here's a hairline fracture at the distal, uh,

6:12

waist and tubercle region, uh, of the scaphoid. It's so easy to see.

6:16

There's the crack and there's the edema surrounding it.

6:20

Here are three sequences, the T one that you've already seen,

6:23

an anatomy sequence. And then in the center is a low field sequence,

6:28

A two D gradient echo. Some of you know it, know it as uh,

6:32

field echo gradient, echo flash.

6:35

And then on the left is a three D gradient,

6:38

echo sequence with slightly thinner sections.

6:41

And I'm sure you're all seeing this, um,

6:44

this granulation tissue that's involving the lunate.

6:47

That's not why I'm showing it.

6:48

I'm showing it for the shininess of the gradient echo,

6:51

the ability to see into the joint.

6:53

These linear black areas are the collapsed capsule.

6:57

The slightly brighter areas on either side represents synovium and the hylan

7:02

cartilage. And you can see that best on this three D gradient echo sequence.

7:06

By the way, you can also see it on the T one.

7:08

There's the very thin collapsed capsule in black,

7:11

and there are the hyland cartilages on either side that are gray.

7:16

Now a related sequence to these,

7:18

these gradient echo sequences is the steady state free procession,

7:22

also known a a as fiesta.

7:25

And this sequence also gives you heavy water weighting. It's very robust,

7:30

so it allows you to get the field of view down to around 7, 6, 5.

7:33

These are one millimeter slices, 1.2 millimeters.

7:37

And look at the band like portion of the scap lunate ligament, that's gorgeous.

7:41

The radial collateral ligament, the lu NATO triquetral ligament,

7:44

which is intact. And then some tearing out here in the periphery of the T F C.

7:48

But I'm showing it for technique,

7:51

not necessarily for pathology just yet. Now,

7:54

some extreme situations, um,

7:58

I'm going to use extreme c pronation and, and supination,

8:03

uh, to evaluate the radial nerve joint. And I'll do it with both hands. Now,

8:07

I can't see myself, am I on video guys? I'm on video.

8:12

So extreme pronation and extreme supination will allow me to

8:16

assess the radial ulnar excursion on the two sides.

8:20

So it's really hard to make that interpretation, uh, on one side only.

8:25

So I will do it bilaterally. You can do it with ct, you can do it with M R I,

8:29

and I haven't had any trouble getting that reimbursed by, uh,

8:32

insurance companies here in the United States.

8:34

Then we've got steep radial and ulnar deviation that I use for the proximal

8:39

carpal intrinsics, the scapholunate and the lu NATO triquetral ligaments,

8:43

such that I very uncommonly have to do an arthrogram of the wrist.

8:47

Then I've got scaphoid views,

8:49

what I call compound oblique images that I perform on CT and mr.

8:53

And then I also have some sequences and positions that I use for radial

8:59

ulnar relationships. This is known as variance,

9:02

and sometimes I'll use a clenched fist view for, for that purpose.

9:06

And sometimes I'll bring the patient back for some of these sequences.

9:09

So here we are,

9:10

and supination and pronation showing you that there can be quite dramatic

9:14

excursion between the radius and the, the center of the ulna.

9:19

And it is extremely helpful and much more reliable to have bilateral

9:24

assessment of both risks, uh, to make such a diagnosis.

9:29

Now here is a, a coronal reconstruction of a, a wrist.

9:34

But if you're imaging that wrist axially and it's for a scaphoid problem,

9:38

you do not wanna,

9:39

you do not want to image in the orthogonal axial projection.

9:43

You really want obliques, what, what we call compound oblique scaphoid views.

9:48

So you take your, your scaphoid, you draw long axis down it,

9:52

there's a compression screw in place, and then you get this,

9:55

which is a short axis oblique. You then take another oblique off that.

9:59

So you can see it's a very compound, uh, sequence.

10:02

We're starting to see the fracture, we're starting to see the screw.

10:05

We get something that looks like this,

10:06

another compound oblique along the long axis of the screw.

10:10

There's the fracture right there.

10:12

And now we have the entirety of the scaphoid in view. We can scroll that.

10:17

We can count slices.

10:19

We want 50% bridging 5.0 to allow a player to return to

10:24

any type of contact sport, lacrosse, American football and, and so on.

10:29

You can see a lucency here. I'm showing it for the technique.

10:32

There is the compression screw seen. It's in entire entirety,

10:36

in normal position. And then you can scroll through that.

10:39

And as you get to the next slide, you can see there is an area of, of malunion,

10:43

and you have to count slices to get to that 50% number

10:48

that allows that patient go to go back to their activity. Similarly,

10:52

compound oblique on m r i, there's the first oblique.

10:55

There's the second oblique, and then here is the final oblique result of that,

11:00

which is a long axis view of the scaphoid laid out in profile.

11:04

This one being normal. Here's another example of a special sequence.

11:10

Again, i i, I don't often inject the wrist

11:15

when I do,

11:16

it's either a scap o radial injection or a radial ulnar joint injection.

11:21

Um, maybe one out of a hundred w would be as frequently as I do it.

11:25

Here's a patient non-contrast. They did put contrast into this joint.

11:30

Did not need it. Highly suspicious for, uh,

11:34

scapholunate ligament insult because the space is too wide,

11:38

it's a little too swollen. Hey, you're all radiologist.

11:40

Compare that with the all no TriCal interval.

11:43

They look very different from one another.

11:45

There's a little brighter signal right here,

11:47

and then the secondary sign of invagination,

11:51

of capsular synovial tissue into the lunate. Best seen here.

11:55

When we ulnar deviate the fluid kind of comes in and shows you this big gap,

11:59

but you really didn't need it.

12:01

You could have gotten it with ulnar deviation without the contrast inserted into

12:05

the wrist. Why did we do it? The clinician just wanted it projections.

12:10

This also is a rule of thumb that applies throughout the body

12:15

axial. That's, you know, that's our comfort zone. You know,

12:19

we're used to looking at axials. So we use this for masses,

12:23

for tunnel syndromes. I also use it for loose bodies, by the way,

12:26

the sagittal view, anything that's running long, so tendons,

12:31

vessels. And also I use it to look at various complex instabilities.

12:35

The coronal, the workhorse sequence for the risk. I use it for all else,

12:39

especially the triangular fibrocartilage.

12:42

Let's start out with a little bit of axial imaging.

12:44

Here we are at the tubercle of the trapezium,

12:48

the proximal carpal tunnel space. There is the flexor retin aum.

12:53

Here is the canal in which the ulnar nerve subsist.

12:58

This is Ian's canal. Here's the carpal tunnel space. The median nerve,

13:02

often round or triangular surrounded by the sublimes tendons deep

13:07

are the profundus tendons. Here's the flexor lysis longus.

13:11

Here's the flexor carp radialis, which goes towards the,

13:15

the greater angular. And then as we get a little more distal,

13:19

we're at the distal carpal tunnel level.

13:22

We know that 'cause hook of the hamming.

13:23

So tubical of the trapezium proximal with the pisiform hook of the hamate

13:28

distal, although not drawn that way.

13:31

The median nerve tends to be flatter at this level with a lot of the same

13:35

anatomic structures you saw before.

13:38

And the ulnar nerve is divided into a deep motor and a superficial radial,

13:43

uh, a, a superficial, uh, uh, sensory branch.

13:48

So here is the extensor compartment, and we have, uh,

13:53

any one of six compartments here. We've got the first,

13:57

the abductor lysis longest, the extensor lysis brevis.

14:00

One way to remember this is longest brevis longest, brevis longest.

14:05

And then you're off and running. So abductor lysis, longest extensor lysis,

14:10

brevis extensor carpi radiologist, longest and brevis,

14:13

longest brevis extensor lysis longest back to longest.

14:18

Then we're at the communal tendons, then we're at the extensor digit mini.

14:22

Easy to remember 'cause of the pinky finger.

14:24

And the extensor carpi narrows with its sub sheath to be differentiated

14:29

from the superficial Retin aum.

14:33

And then here are our flexor tendons that we described earlier.

14:37

I don't think we need a second description for them. The sagittal projection,

14:42

using this for instabilities alignment, tendons, vessels,

14:47

anything that's long and straight.

14:49

And also for the pizzo triquetral articulation.

14:53

Here are those tendons. Here are the profundus tendons right here.

14:56

Profundus tendon. Sublimes tendon. We're at the midline.

15:00

We've got the capitate, we've got the lunate, we've got the radius.

15:04

They're all lining up relatively straight.

15:06

So we have what we call our mid middle column alignment. Unfortunately,

15:11

my, my pen is not working today. Okay,

15:15

we've got our middle column alignment that goes from distal to proximal and

15:19

goes right through by sex, decapitate by sex, de illuminate by sex. The radius.

15:24

And then here with a yellow arrow is the attachment of the radio

15:30

scavo capitate ligament, which prevents not shown yet.

15:34

Stay tuned. Rotatory subluxation of the scaphoid.

15:38

We're gonna see one detached a little bit later.

15:40

And here's the short radio lunate ligament drawn in.

15:43

Little hard to see on the m r I.

15:48

Here's a series of sagittal views showing the normal architecture and

15:52

alignment of the metacarpals, the, uh,

15:57

the lunate and the scaphoid.

16:00

And if we look at the angle of the scaphoid and goes straight distal to proximal

16:05

in an orthogonal fashion,

16:07

this angle right here along the long axis of the scaphoid between these two

16:11

should be around 45 to 60 degrees. So if the lunate, uh,

16:15

sorry if the scaphoid starts to rotate and sag downwards so that it's almost

16:20

horizontal, we know that we have a rotatory instability problem.

16:25

It's that simple. And I try not to do, you know,

16:28

too much unnecessary measuring and I use my,

16:31

my eye a lot for expediency.

16:34

So back to this high resolution coronal, uh, T one weighted image.

16:39

Uh, this is the workhorse for the wrist.

16:42

We see the scapholunate and lu NATO triquetral ligaments.

16:46

Here is the rather, um,

16:49

trapezoidal shape of the triangular fibrocartilage.

16:52

It looks triangular in the axial projection. Here are the radial attachments.

16:57

No, that's not a tear. That is radial highline cartilage.

17:00

That is ulnar hiim cartilage and synovium.

17:03

There is the foveal attachment right there. There's the styloid attachment.

17:08

And right there is one of the distal attachments known as the ulnar carpal

17:13

attachment. These wispy structures represent the ulnar collateral ligament,

17:17

not a true ligament, but a condensation of the ulnar capsule.

17:22

Let's move on now and discuss in greater detail.

17:26

One of the most important structures. The triangular fibrocartilage complex.

17:32

The complex consists of the fibrocartilage like

17:37

structure. Its radial attachment.

17:40

The distal radial ulnar articulation,

17:43

the tissues underneath between it and the hylan cartilage of the ulna.

17:48

The hylan cartilage of the lunate, the cortex of the lunate.

17:51

Here's the meniscus hoal analog. It's an artifact of preparation,

17:55

but here's the small triangular shape lu NATO triquetral ligament and

18:00

this vascular pedicle here right in the middle is known as the ligamentum crewe.

18:05

And just distal to the ulnar styloid is the pre styloid recess.

18:10

Here's the mr that matches that T one on the left. Um,

18:15

water weighted on the right there is the radial highline cartilage.

18:20

There is its attachment. There's the distal radial ulnar articulation,

18:23

mostly collapsed. Tiny bit of fluid inside it.

18:27

There is the synovium and hylan cartilage of the ulna that of

18:32

the lunate, the lu NATO triquetral ligament.

18:35

The meniscus holo styloid attachments,

18:38

which are pretty broad foveal attachments, which are a little bit more narrow.

18:43

And there's the hyperintense ligamentum tum with the barely seen,

18:48

uh, pre styloid recess,

18:51

still even higher resolution. Uh, at the level of the radius.

18:56

There's the radial attachment. Again,

18:57

do not confuse the radial cartilage with a vertical tear.

19:02

Most tears are gonna be in the central or inner third of the triangular

19:06

fibrocartilage. There's a little bit of synovium and cartilage of the ulna.

19:10

And the same for the lunate.

19:13

Headed over towards the ulna meniscus hoog peripherally.

19:17

Then here we are, uh, again,

19:20

higher resolution drilling down into the ulnar styloid.

19:24

There's the pre styloid recess that has a few different variations that are a

19:29

bit beyond the scope of our discussion today here,

19:32

highlighted by our white arrow anatomy. On the left, Mr.

19:36

On the right there is the foveal attachment.

19:39

And here's the broad styloid attachment with a hyperintense

19:43

central vascular pedicle. The ligamentum crew attom.

19:51

Here again, high resolution still.

19:53

We once again see the triangular fibrocartilage radial

19:58

attachment, which is pretty broad peripheral attachment to the meniscus

20:03

hoog. Here's a foveal attachment,

20:06

not showing you the the styloid attachment in this case.

20:09

But here's another really interesting structure right here from the triangular

20:14

fibro cartilage.

20:15

There's this subtle structure going to the lu NATO triquetral ligament that is

20:20

known as the ulnocarpal ligament.

20:22

There's a similar ligament that goes to the lunate, the ulnolunate ligament.

20:26

And there's one that goes to the triquetrum, the ul, no triquetral ligament.

20:30

Neither of those latter two are shown at this juncture.

20:34

But here is a more peripheral slice.

20:36

So here's a sagittal slice done out here where

20:41

we're more aptt to see structures that attach the T F

20:46

C to the triquetrum. Let's have a look.

20:48

We're all the way out to the ulnar side of the wrist. We've got some basic,

20:53

basic anatomic drawings here,

20:57

showing you the vola aspect of the wrist right here in the sagittal.

21:01

Let's focus on this. Here's the triquetrum. Here's the triquetrum.

21:06

Here is the triangular fibrocartilage with its attachment to the Palmer radio

21:11

ulnar ligament.

21:12

And its distal attachment to the ul no triquetral attachment

21:17

right here. There's one dorsally,

21:20

a dorsal ulnar triquetral attachment.

21:23

And it blends with the dorsal radial ulnar ligament.

21:27

So you see the triangular fibrocartilage is tethered anterior.

21:31

It's tethered posterior. It's tethered medially. It's tethered laterally.

21:35

It's tethered distally and it's also tethered proximally.

21:39

So it's a rather complex structure that is kind of floating

21:44

like a trampoline supported by any one of a number of of structures.

21:50

Now let's talk about the, let's talk about the uh,

21:55

triangular fibrocartilage classification of injuries.

21:59

Now I'm not a big classification person.

22:01

I mean there's so many classifications for fractures.

22:04

You could go absolutely bonkers trying to learn them all.

22:06

But there are certain classification systems that our colleagues like they rely

22:11

on it, it's in their comfort zone, therefore you should use it.

22:15

And who are those clinicians? Hand surgeons.

22:19

So if you're playing to a general orthopedic surgeon, probably not necessary,

22:24

certainly not to a family doctor, but to a hand surgeon. Gotta know this.

22:28

So class one a central perforation,

22:31

B peripheral tear, and with or without a styloid fracture.

22:36

C involvement of the distal and sometimes proximal attachments.

22:41

And D radial uls, which is quite rare.

22:44

Class one refers to traumatic injuries of the triangular fibrocartilage.

22:49

You'll see that class two refers to all no lunate abutment or chronic injuries

22:54

of the triangular fibrocartilage complex.

22:58

So here is a central third perforation,

23:01

the most common type of traumatic injury of the T F C.

23:05

These are treated conservatively.

23:06

They're too small to put a stitch in so you don't operate on them. Um,

23:11

you rest them a little bit and they usually will granulate in a little fluid in

23:14

the distal radial ulnar articulation.

23:17

We would call this a polymer one A, a central perforation.

23:22

And the clinician would immediately understand what you're talking about.

23:25

Here is our polymer one A. In the sagittal projection,

23:28

there are dorsal attachments to the dorsal radial ulnar ligament.

23:33

Our volar attachment is right here. We don't see our uh uh, vola all,

23:38

no triquetral attachment very well.

23:39

But we will later in another case there is our hourglass shape.

23:44

T F C. There's our tear, our vertical tear not so vertical.

23:48

It's a little bit oblique in the sagittal.

23:49

It's kind of like looking at menisci of the knee.

23:52

And here is our triangular shape right there of our T F C.

23:57

We're missing this part of the triangle right here 'cause it's torn,

24:00

allowing fluid to exit from the distal radio ulnar joint into the

24:05

vola recess.

24:08

Here's another example of a traumatic T F C tear.

24:12

This time we are not involving the central third of the T F C.

24:16

We're involving the periphery. Let's have a look for,

24:19

if he doesn't look too bad,

24:20

there's the meniscus holo and it is blending with the ulnar

24:25

triquetral ligament. There's the LT ligament,

24:29

the attachment of the T F C to the LT ligament.

24:33

And as we keep going, look at what happens. The periphery turns to mush.

24:38

We don't see a strong dark band like or

24:43

fan like attachment to the ulnar styloid nor to the fovea.

24:47

It is detached. This high signal intensity material is edema.

24:52

In the ligamentum tum,

24:53

there's swelling of the presty recess and you can see some of the

24:58

attachments dorsally right here in the sagittal projection.

25:02

And there is a vola attachment right there.

25:05

So this is a peripheral T F C tear one B,

25:10

there's another one. This is, this one is a bit more central.

25:13

I promised I would show you the,

25:16

the uh o no triquetral ligament. There is a central tear,

25:20

but there's also a peripheral tear too. It's a little bit swollen out here.

25:25

Now if you go back and remember the,

25:26

the one that I showed you earlier on was a bit thinner.

25:30

It wasn't so blurry looking. Here's your T F C,

25:33

here's some intrinsic tearing of the T F C,

25:36

but there is your fat chubby uh, uh,

25:40

ligament that goes to the triquetrum, uh,

25:43

as part of the T F C peripheral distal stabilization. And here it is again.

25:48

Look how fat that thing is.

25:50

So the patient has both a central injury and a

25:54

peripheral slash distal injury. Let's talk about variance.

25:59

Now,

26:02

variance is the relationship between the ulnar platform and the

26:06

radial platform.

26:08

So if you take this crux right here between the styloid and the body

26:13

and you compare it to the free edge of the radius,

26:16

it should be about eight millimeters. Either way within that line,

26:20

if it's too far forward, positive ulnar variance, if it's too far back,

26:24

negative ulnar variance.

26:26

Here's an example of somebody with negative ulnar variance.

26:30

You're more than a centimeter proximal to the free edge of the

26:35

radius. What happens to these people? Unbeknownst to many of you,

26:40

they have a high incidence of extensor carpe narrows injuries.

26:44

They have a high incidence of peripheral,

26:47

not central peripheral T F C C injuries.

26:51

And they also have this a board question.

26:53

An increased incidence of keen box disease or lunate necrosis positive

26:58

impaction syndrome may impact the lunate, may impact the T F C,

27:03

the ate triquetral ligament.

27:04

And you can even get styloid impaction on the triquetrum.

27:10

Here is an example of the classification system for these types of

27:15

impaction.

27:17

This is the Palmar class two system thinning of the T F C due to

27:22

wear a b ludo or UL chondromalacia

27:27

C perforation of the central T F C D

27:31

dreaded tearing of the ludo triquetral ligament and E generalized

27:36

carpal arthritis. Let's have a look. This is an easy one.

27:40

The patient has had a very serious complex bridged fracture

27:44

of the radius. There is for shortening.

27:48

The fovea of the scaphoid right here is destroyed.

27:52

There's some arthritis developing in the lunate, but,

27:55

but the money is over here where the ulna is jutting way

27:59

forward relative to the free edge of the radius.

28:02

It has just destroyed the triangular fibrocartilage.

28:07

It's hard to see a triangular shaped LT ligament. It's torn.

28:11

And there's extensive irregularity in the periphery of the T F

28:16

C C severe end stage abutment in acquired

28:21

positive ulnar variants from a prior radial fracture. Here's another one.

28:26

This time we are not impacting the central third so much

28:31

of the T F C, even though it is a bit attenuated. So there's some disease here,

28:36

but I am showing it for this.

28:38

This is a piece of the ulnar styloid that has broken off that in ulnar

28:42

deviation is getting slammed into the triquetrum.

28:46

Now normally there is a little indentation here of the trium,

28:49

so you don't want to confuse that with an O C D.

28:53

But when you see this object fitting in the indentation and then you have edema

28:58

deep to the indentation,

28:59

you know that you are impacting the structure against the triquetrum.

29:03

And the patient has also torn their ulnar capsule.

29:08

There's another example of a TF CCC injury this time.

29:13

Not positive ulnar variants, but negative ulnar variants. Now, you know,

29:18

kBox disease, we don't have that in this case,

29:21

but what do we have an increased risk for extensor cario narrows injuries and

29:27

peripheral T F C C terrace. Let's have a look.

29:31

Negative ulnar variance. There's our ulnar styloid,

29:34

there's our body and the crotch or crux between the styloid and the

29:39

body way proximal to to the radius. There's our T F C.

29:43

It does not land on the styloid,

29:45

it does not land on the fovea.

29:49

It does not have a clean attachment to the distal lu NATO triquetral

29:54

ligament. And we never really identify a distal,

29:58

uh, attachment to the triquetrum. Right here we do see a proximal one,

30:02

but not a distal one. And look posteriorly, posteriorly,

30:06

there's no attachments to the dorsal radial, the ligament.

30:09

It's just mashed potato swelling of the posterior aspect of the wrist.

30:14

So we have a dorsal attachment problem, a peripheral attachment problem,

30:19

all associated with negative ulnar variants. And we better check,

30:22

we're not doing it yet, but we better check the E C U,

30:25

which we would do as the next step.

30:28

Let's turn our attention back to the extensor tendons. Remember,

30:31

we've got longest brevis longest brevis longest, and then the digitorum,

30:35

the digit mini and the e c u.

30:38

Another important structure in this projection is lister's tubercle for

30:42

fractures, irregularities, and deformities of lister's.

30:45

Tubercle may lead to contraction of the extensor reticulum.

30:50

And as the E P L crosses over here to meet

30:55

the thumb, these two structures,

30:57

compartment two and three may friction over one another may rub

31:02

together and give you what's known as distal intersection syndrome.

31:07

So let's talk about intersection syndrome.

31:10

I'm not gonna show you that intersection syndrome.

31:13

I'm gonna show you a couple of others. And, um,

31:17

but let's start out with the,

31:18

the most common intersection syndrome in younger individuals. Sorry,

31:23

the most common extensor tendon that is affected in,

31:27

in in younger individuals, not intersection syndrome.

31:31

And that is below age 80.

31:32

And that is the E C U that is affected more frequently in people with ulnar

31:37

variants. Compartment number one,

31:40

the abductor lysis longus and extensor lysis. Previs, which you know,

31:43

as the Devan compartment, uh, has a crossing of the,

31:48

the two structures. And so that is a form of intersection syndrome,

31:52

namely devans disease.

31:55

And you do get contraction of the reticulum.

31:58

That leads to s stenosing, uh, teno synovitis.

32:02

And then there's another intersection syndrome that I'll show you a little bit

32:05

later very briefly,

32:07

that occurs in the arm between the extensor lysis long longest and

32:12

the extensor carp radialis, similar to that in the hand.

32:15

So three intersection syndromes, one in the forearm,

32:19

one in the dequeant compartment,

32:21

and one in the hand between compartments two and three. And as we said,

32:26

fractures of lister's, tubercle, and deformities. As such,

32:30

put the patient at risk for intersection syndrome.

32:33

So here's an example of dequeant compartment number one

32:38

intersection syndrome where there is marked

32:42

hypertrophic irregularity and proliferation of soft tissue and even

32:48

synovial tissue. And remember,

32:50

these structures have multiple tendon slips,

32:54

so it's very common to over-diagnose interstitial laminar tears

32:59

of the first compartment.

33:00

So you have to be very careful about that diagnosis and use the axial projection

33:05

with, with a, a very discreet,

33:08

near full depth area of signal to make the diagnosis of a tear as opposed to

33:12

hypertrophic deforming S stenosing 10 synovitis,

33:17

which is a subset of intersection syndrome.

33:20

There's also an erosion of the radial syl more on that a bit later.

33:24

Here we are in the short axis view.

33:26

There is so much inflammatory tissue from this crossover

33:30

intersection,

33:32

S stenosing 10 synovitis that you can hardly see the tendons.

33:36

You see them very as very, very tiny dark little structures.

33:39

But remember there are multiple tendon slips here and this seeming

33:44

discontinuity does not in itself mean that there is a tear.

33:48

Now this is describing the anatomy of the the crossover syndrome.

33:53

This is gonna take a little too much time.

33:55

I just wanna point out to you that in the forearm there is a third intersection

34:00

syndrome, the proximal type. And this is what it looks like. And,

34:05

and I'm not gonna talk too much about that today.

34:07

I just wanted you to see that there are multiple intersection syndromes and as

34:11

you get more distal into the wrist, it persists.

34:14

So not only does this patient have it in the upper arm,

34:17

they also have it in the hand right there.

34:20

Look at the swelling around the E P L and the extensor

34:24

Carpe radialis longest and brevis.

34:27

Those three together are showing you that this patient has both proximal and

34:32

distal crossover or intersection syndrome. Three types.

34:37

And you've seen all three. The extensor carpi narrows,

34:40

we said this is the most common extensor tendon to be affected in young

34:45

individuals. The most common in elderly individuals is the first,

34:49

the Devan compartment, the E C U inserts on the base of the fifth.

34:53

It's held in place by a sub sheath, not a Rett aum.

34:56

A sub sheath over top of that is the extensor reticulum.

35:01

And there are stabilizing fi fibers of the lineage.

35:03

Ag got which extend from the base of the ulnar styloid to the

35:08

extensor reac subs sheath injuries,

35:11

even with an intact extensor reticulum often lead to subluxation.

35:16

So here's a diagram showing you the E C U in its groove.

35:19

I allow a fair amount of latitude to the E C U as long as I don't see swelling

35:24

there,

35:24

I don't mind if it pers on the YL as long as I can see this or I have

35:29

no swelling and no focal high signal in the

35:34

tendon itself.

35:36

Now don't confuse the extensor Retin ulu with the sub sheath.

35:40

If it's perched and I have swelling and I have a sub sheath that's interrupted,

35:45

I get worried and I'm going to call it out.

35:49

So here we are with four consecutive views.

35:52

This is the E C U part one, there's part two,

35:56

there's no two parts to the E C U.

35:58

It is split much like you would see a split of the perineal brevis

36:04

in the foot. There is the subs sheath right there.

36:08

That's the reac on top of that. Yes, very, very subtle teased out findings.

36:13

There is the interruption of the sub sheet that has allowed the E

36:18

C U to split and portions of it to dislocate over top of the ulnar

36:23

styloid. Here's some other examples of E C U disease.

36:27

Now I'm not gonna get into tendons per se 'cause we're gonna talk a lot about

36:31

that in the September course with Dr Doctors Resnick and Chang and colleagues.

36:36

But you know, there's peritendinitis, there's peritonitis, there's tendinopathy,

36:41

there's tendinosis, there's tendonitis,

36:43

and we're gonna winnow those out for you at at a later date.

36:47

But right now I wanna show you an example of teno synovitis to make that

36:51

diagnosis. Your structure has to have synovium. For instance,

36:55

the Achilles know synovium.

36:58

So you don't use the term teno synovitis.

37:01

You might in the proper setting use the term para tendonitis more about that on

37:05

another day.

37:06

But here we have tenino synovitis with tissue that is not simple fluid

37:11

that is synovial hypertrophy and fluid.

37:15

That is proac surrounding the E C U in this patient with

37:19

ra. There's another example of an E C U problem. Uh,

37:24

this patient has ruptured the E C U at the base of the fifth.

37:27

That was a low field image.

37:28

As a higher field image is a patient that is a pitcher that is complaining

37:33

vehemently about his on the wrist. And he is got this tiny little tear,

37:37

which probably wouldn't bother me because I'm not throwing a ball 90 miles an

37:41

hour. But this person is,

37:42

it's a small interstitial tear of the triangular fibrocartilage.

37:46

Now let's turn our attention to instability and look at a hand surgeon's,

37:51

uh, classification of instability.

37:54

We've got acute less than a week,

37:56

subacute one to six weeks and chronic greater than six weeks.

38:02

Then we've also got what's known as constancy. Pre dynamic.

38:05

There's no instability from mal alignment on imaging only

38:10

symptoms. Dynamic mal alignment is only demonstrated with stress views.

38:16

Radial ulnar, radial deviation, ulnar deviation, pronation, supination,

38:20

clenched fist view, and then static.

38:22

There's permanent mal alignment seen in the neutral position on a standard

38:27

M R I. Let's look at some anatomy here. If we can get our uh,

38:32

video working. I don't think we're gonna get it working. Click, click it.

38:36

All right, there we go. Thank you. So this is a high resolution image.

38:40

I wanna just let you toggle through it and I'm gonna stop it right here.

38:45

Let's see if I can back it up. There is your radial collateral ligament.

38:49

Let's back it up a little bit more.

38:53

And there are some of your extrinsic ligaments.

38:57

Look at this extrinsic ligament right here. The radio scavo capitate ligament.

39:02

It's a long lar ligament. Here's a short lar ligament.

39:07

The short lar ligament is known as the arcuate ligament.

39:12

That's gonna be important. Uh,

39:14

along with this other ligament here in patients with vola and turchary segmental

39:18

instability.

39:19

This one is important in rotatory subluxation of scaphoid.

39:23

The one right underneath it, let's see it right here.

39:27

The one right underneath it is known as the long radial lunate

39:32

or radio ludo triquetral ligament.

39:35

Now I'm not gonna get you too involved in the extrinsic,

39:37

so you don't pull your hair outta your head.

39:39

I wanna show you one dorsal extrinsic, but before I do the vola extrinsics,

39:44

make an inverted V. You've got some long vs and some short vs.

39:48

I'm gonna break that down for you in a few moments.

39:51

But just remember inverted V,

39:54

there's also a weak spot right here called Corona space where none of the

39:58

vs really provide a lot of support.

40:01

So the carpus can come at you and can say proximally.

40:05

Very important biomechanical concept because my thing as opposed

40:10

to anatomy is biomechanics.

40:12

Some of my colleagues are more anatomically oriented.

40:15

I'm more biomechanically oriented.

40:18

So now let's keep going and go to the dorsal aspect of the wrist. Here we come.

40:24

I'm just gonna show you one ligament, so don't get scared. Here it comes

40:31

right here. Whoops. Oh no, shouldn't have clicked it. Hold on.

40:35

I got it right here.

40:41

Right there. This is the dorsal intercarpal ligament. Yeah,

40:45

there's some other ligaments proximal to it too,

40:47

but this is one that gets injured when you fall on an outstretched hand.

40:54

Now let's look at some of the intrinsics. Those are some extrinsics.

40:58

Let's look at the intrinsics. The intrinsics include the scapholunate ligament,

41:03

which we see here. I have a little mnemonic.

41:06

L T V Ss L V ss l v.

41:09

The sca scapholunate, uh, sorry, L T V.

41:13

The lu NATO triquetral ligament is stronger on the volar side. S L D,

41:19

the scapholunate ligament is stronger on the dorsal side.

41:23

So the dorsal portion of the s l ligament is more band like.

41:27

The middle is triangular and sometimes it'll have a little cleft in it.

41:31

That's okay.

41:32

I also don't mind this little cleft in the lu NATO triquetral ligament as long

41:36

as this space looks proper. And then as we get into the vola aspect,

41:41

this is a bit weaker.

41:43

The SL ligament is kind of trapezoidal in shape and here are some diagrams

41:47

to reflect just that.

41:51

Now let's look at the Ludo triquetral ligament that likes to honor the

41:55

great artist Salvador Dolly with Salvador Dolly's bar shaped

42:01

mustache.

42:02

Remember we said the triangular fibrocartilage has carpal

42:07

attachments, some to the lunate.

42:11

We can barely see one right here.

42:13

Some to the Ludo triquetral ligament known as the Ulnocarpal

42:18

attachments. There's one right there.

42:20

And then we also showed you earlier some to the trium.

42:24

There's the base of one right there.

42:27

All ulnocarpal attach. But look at our LT ligament.

42:32

It's a triangular nubbin, it's a broad triangle.

42:36

It's a crisp triangle with a little bit of a mustache. It's eccentric.

42:40

It's now got a bilateral bar shaped mustache. This is all, uh,

42:45

imaging taken from the same patient. So look at the variability.

42:50

You can see why some people are uncomfortable diagnosing LT

42:55

ligament tears without an arthrogram. I however am not,

42:59

I'm used to all these variations and I use the secondary signs,

43:03

the absence of arthritis, no fluid, a collapsed capsule.

43:07

Perfect hi in cartilage.

43:09

I am totally comfortable with this LT ligament without putting contrast in the

43:14

joint. Let's look at some intrinsic failure.

43:18

Let's look at SS scfo, lunate degeneration and tears. Widening synovitis,

43:22

pseudocyst erosions. You may get rotation of the lunate.

43:26

You may get dynamic changes on radial deviation and ulnar deviation,

43:30

which you've seen already.

43:32

And you might get the capitate migrating approximately.

43:36

And lar, if the patient develops a more complex pattern of instability,

43:40

this one's easy. You didn't need an arthrogram,

43:43

we did it to appease the clinician.

43:46

You could drive a a Buick through this giant hole between

43:51

the scaphoid and the lunate. There's the floating scapholunate ligament.

43:56

This is the membranous mid triangular portion,

43:59

but the whole thing was torn from front to back,

44:03

yet there is no rotation or displacement of the lunate.

44:07

And there wasn't any rotatory displacement of the scaphoid either.

44:11

Here's one that's a bit more subtle.

44:14

I do not need to give contrast in a case like this. Uh, I already know that the,

44:18

the s sl ligament is torn. I might do radial and lar deviation,

44:23

but look at the difference between this and this.

44:26

Now if I have to know the percent tear, then I might go for the arthrogram.

44:31

But that is indeed a rare event.

44:33

And if you look at all the slices at very high resolution,

44:37

especially with radiant and ulnar deviation, you will be able to tease this out.

44:41

But it is the secondary sign right here of widening and swelling compared to the

44:46

LT interval that makes the case for you very easily. Here's another one.

44:51

We do see a sick looking but present SL ligament.

44:55

It's irregularly shaped on the T one.

44:57

It's a little better shaped on the PD spur,

45:00

but we know something nasty is going on here because we have arthritis,

45:04

arthritis there and a little bit of arthritis here.

45:06

So right at that intersection we've got micro instability.

45:10

So in a case like this,

45:11

if my radial and ulnar deviation fails to show the widening that I'm

45:16

anticipating,

45:17

then this might be one of those cases where we would inject and perform an

45:22

MR arthrogram case like this. Not by the way, in that last case we did,

45:27

this was not a full thickness tear. There was no communication.

45:31

It was just a stretched,

45:33

insufficient ligament that allowed for micro instability.

45:37

Here's one that's obvious. Uh, there's a huge defect here.

45:41

The so-called Terry Thomas sign with a space in the

45:45

incisor tooths, uh, of the front of the mouth right there. There's the lunate,

45:49

there's the scaphoid, and then the axial,

45:52

which shows you the scapholunate ligament,

45:55

which was here and is now fallen into this hole. There it is.

46:00

It's trapped inside between the scaphoid and the

46:05

lunate. So this is one that's going to need a surgical extraction.

46:09

Radial ulnar failure.

46:11

This happens when you have insufficiency of the volar,

46:14

less commonly the dorsal radial ulnar uh, ligament.

46:18

It allows for excessive excursion of the ulna related to the

46:23

radius. You put a a.in the middle of the ulna, a.in the middle of the radius,

46:28

and you should stay within about five to eight millimeters of the central dots

46:32

of both when you go into steep croation and, and supination.

46:37

But there's going to be some movement and comparison with the other side is

46:41

important. Now, when you're looking at these spaces,

46:45

a knowledge of their communication is important.

46:48

And we will drill into that at our combined course in September.

46:53

Um, the radio ulnar bursa communicates with a horse shoe shaped hand bursa

46:58

about 70% of the time. There are other bursa in the wrist. There's Athena bursa,

47:02

there's a mid carpal bursa, there's a flexor lysis longus bursa.

47:06

And those will be stories four another day.

47:10

But here's an axial diagram and an axial M r I look at that dorsal

47:15

floating ulna.

47:18

There's a little bit of the triangular fibrocartilage.

47:21

We can't see the volar ligament because it's a T one weighted image.

47:24

You'll see it in a minute.

47:26

But look at how dorsally displaced the ulna is and there's a stubby

47:31

stump of the dorsal attachment of the T F C to the

47:36

triquetrum right there. It just ends pretty suddenly.

47:39

So it's a rather complex case,

47:40

but I'm showing it for the vola radial ulnar ligament tear.

47:44

There's one end of the vola radial ligament.

47:46

There's the fray destroyed ola radio ulnar ligament.

47:50

There's the dorsal floating ulna.

47:53

And because of the stresses it puts and the stretch on the

47:58

extensor support of the E C U,

48:00

the E C U is now starting to plow its way through the sub sheath and

48:05

ret. So everything is really a, is connected to B, connected to C.

48:10

And if you know what you're looking for, you're more likely to to find it.

48:14

Here's a patient with radio ulnar instability for years.

48:18

Look at the widening of the radio ulnar articulation and then the sagittal

48:22

projection. You'd make this diagnosis on a plane film,

48:25

but many people do miss it.

48:26

Look at the dorsal displacement of the ulna and look at the very

48:31

irregular chopped up appearance of the dorsal aspect of the T F

48:36

C. Here. It looks pretty good other than being thinned,

48:38

it's very thin here it looks a little irregular,

48:40

but here it's just attenuated dorsally.

48:44

So the dorsal attachments are gone. Here's yet another one.

48:48

This is a patient without a lot of displacement of the ulna,

48:51

but with severe chronic longstanding wrist pain.

48:54

It is an athlete look at the fluid and the distal radial ulnar articulation.

48:58

And there's one end, one end,

49:01

and there's the other end of the normally connected volar radial ulnar

49:06

ligament. There's the defect right there. So volar, radial ulnar ligament, uh,

49:11

rupture with, uh, dynamic radial ulnar instability.

49:16

So on the static it didn't look unstable,

49:18

but on the dynamic that thing floated all over the place. Extrinsics,

49:23

we've already talked about some of the key extrinsics.

49:26

One is the radios scfo capitate ligament.

49:30

The other is the long radio NATO triquetral ligament.

49:34

We're just gonna focus on this one today.

49:36

We look at it all the time when we have complex instabilities.

49:41

And those are really the two. You should concentrate on these short ligaments.

49:45

I'm not so interested in this short ligament from the hammit to the

49:50

capitate. I'm not so interested in you learning about it,

49:53

but just know that this is one of the divisions of the arcuate ligament that

49:58

helps support the center of the mid carpal space and prevents the capitate from

50:03

coming at you and migrating proximally,

50:06

especially in especially in vola, in ary segmental instability.

50:11

So this is your big one here. This is primary. This one is your,

50:14

your secondary area of interest. And in the volar wrist,

50:19

the ligaments make an inverted v. So here's a little bit, uh,

50:23

of drilling down into the extrinsics. Again,

50:27

here is our radios scfo capitate uh, ligament.

50:31

Here's another long ligament that also supports the ulnar aspect of the wrist.

50:36

Here's that short amato capitate ligament.

50:40

And together these will be disrupted in patients with visi and

50:45

in ulnar sighted wrist clunk in dorsal ary segmental

50:49

instability. Uh,

50:50

these may be compromised along with the scapholunate ligament.

50:57

And here are two short ligaments known as the arcuate ligaments.

51:00

When these tear, this is going to allow for a complex instability. Again,

51:05

the capitate is gonna migrate proximal and it's gonna come at you and may

51:09

lead to volar and intercalary segmental instability.

51:12

Here are these short arcuate ligaments in the mid carpal space,

51:17

deep to the carpal tunnel space.

51:19

And when these structures start to sag anteriorly,

51:22

they can compromise the median nerve. Here, uh,

51:26

here are the dorsal extrinsics. They make a sideways V.

51:30

And the one I'm most interested in is the dorsal intercarpal ligament.

51:35

The upper limb of the V or that one gets injured when you fall on an

51:39

outstretched hand. And here it is fall on an outstretched hand.

51:43

The patient has bled into the dorsal intercarpal ligament.

51:47

The treatment is completely conservative, violent, complex,

51:51

carpal instabilities.

51:53

Let's start out with dorsal and ary segmental instability.

51:57

While my pen isn't working,

51:59

you can see that there is a straight alignment between the metacarpal,

52:03

the capitate, the lunate, and the radius.

52:06

If the lunate starts to turn dorsally facing,

52:10

we call that dorsal and ary segmental instability.

52:15

It may or may not be associated with rupture of the radios

52:20

scfo capitate ligament. Here's a normal radios scfo capitate ligament.

52:25

Here's a patient with dorsal and turchary segmental instability.

52:29

Know the radios scfo capitate ligament is not obviously torn on this image,

52:34

but I just wanna show you the dorsal facing lunate.

52:37

It is highly unlikely that this patient is going to have an intact

52:42

scapholunate ligament even before looking.

52:45

There's another example of a normal reference.

52:48

Here's our straight alignment between metacarpal, capitate, lunate and radius.

52:53

And our scaphoid is gonna be at about a 60 degree angle.

52:58

I'll show you what I mean in a moment.

53:00

But let's turn our attention not to dorsal and intercalary segmental

53:05

instability. A dorsal facing lunate, but a vola facing lunate. Yeah,

53:10

we're vola because there are the flexor digitorum sublimes and

53:15

profundus tendons.

53:16

There is your median nerve volume average you are facing Palmer.

53:21

And look at the mid carpal space, it is destroyed.

53:24

Looking at a capitate is starting to work its way proximal and anterior

53:30

on its way to producing secondary carpal tunnel syndrome in a

53:35

patient with visi position or visi posture and severe

53:39

injury of the lu NATO triquetral ligament and other intrinsics.

53:44

There's another complex instability SL ligament. No problem.

53:49

You don't need contrast for this. There's a giant hole here.

53:53

There are the two limbs of the ligament.

53:54

The LT ligament is absolutely positively intact

54:00

and the space between the trium and lu lunate is perfect.

54:05

Here's the sagittal of this patient.

54:07

The lunate is starting to face dorsally and the radios

54:12

cafo palpitate ligament is starting to de-laminate right there.

54:16

It is not allowed the scaphoid to rotator sag yet,

54:20

but it will coming to a theater near you very shortly.

54:24

So a little bit of extrinsic delamination, some dizzy,

54:29

a big sl ligament tear, but no rotatory subluxation of escape for.

54:34

Finally we finished with scapholunate advanced collapse and some more advanced

54:39

stability. This is also known as slack wrist.

54:43

You are looking for proximal capitate migration. The,

54:47

the lunate may migrate to the ulnar side,

54:49

so-called ulnar translocation of the lunate. As you've seen,

54:52

there is extensive arthritis,

54:55

one of the earliest signs and a stage one of slack wrist radial

54:59

styloid hypertrophy.

55:02

You can get secondary av n of the lunate scaphoid rotation,

55:07

destruction of the scaphoid, and then lunate fossa of the radius.

55:11

And then finally, carpal tunnel syndrome.

55:14

Here is the Watson classification or a modification of it

55:19

showing the four stages of slack wrist degenerative changes only in the scap

55:24

styloid tip easy two involvement of the scaphoid phos

55:29

of the radius.

55:30

Three involvement of the lunate phos of the radius and four involvement of

55:35

the wrist in its entirety.

55:38

Let's have a look at a slack one. Sorry, slack two wrist.

55:44

Why is it a two?

55:45

It's a two because there is some styloid involvement right there.

55:49

Look at how pointy it is. That's one of the earliest signs of slack wrist.

55:53

A pointed radial styloid, yes, an obvious SL ligament tear.

55:58

Yes, there is some osteoarthritis and some erosions, but why is it not a one?

56:03

Why is it a two?

56:04

Because there is marked narrowing of the scaphoid fossa cartilage

56:09

where the scaphoid sits in the radius. Look at the gradient echo,

56:12

almost bone to bone. There's still some cartilage here,

56:15

but there's no cartilage here.

56:17

So styloid plus radial fossa,

56:21

stage two slack wrist with scapholunate ligament rupture.

56:26

And to make matters worse,

56:28

the radio scavo capitate ligament ruptured. There it is right there horn.

56:33

And the, the scaphoid is now rotating in a clockwise fashion.

56:38

No longer do you have, uh,

56:41

60 degrees of angulation between the scaphoid and a vertical

56:46

line drawn in this fashion. It's almost horizontally oriented.

56:50

So this patient has a complex pattern of instability that involved

56:55

rupture of the radios scfo capitate ligament.

56:58

Here's another one that's very complex. The SL ligament is destroyed.

57:03

The lunate is now translocating to the ulnar side, just as we said it would.

57:08

In late stage slack wrist,

57:10

the hamate and the capitate are migrating proximally and getting destroyed

57:15

at their base. They're also migrating into a ventral position,

57:20

likely to encroach on the median nerve.

57:24

The T f C has been destroyed.

57:27

The lt ligament has been destroyed and there is rotatory

57:31

malalignment between the lunate and the trium.

57:35

So the intrinsics are completely wiped out.

57:39

If we look at the lunate, it is lar facing, it's facing this way.

57:44

So the patient also has visi. Now this time we have a stage three slack wrist.

57:49

Why is it stage three? Because we have the radial tip involved, not shown.

57:54

We have the radial fossa involved. I didn't show it quite as well as I,

57:59

I might've liked, but now the lunate fossa is involved right there.

58:03

Extensive erosive change of the lunate fossa with a small

58:07

erosion and cyst or pseudo cyst that that is proliferating.

58:12

So now with lunate fossa involvement,

58:14

where at stage three the whole wrist takes you to stage four.

58:17

And here we are at stage four in this patient with

58:22

a p****n cousin of slack wrist. The snack wrist,

58:27

no, it's not Frito lace snacks,

58:29

it is scaphoid non-union advanced collapse.

58:33

This is one proximal fragment of the scaphoid. There's the other fragment.

58:38

So this joint is now serving as a ligament where there is widening and

58:43

instability,

58:44

there is extensive erosion of the scaphoid fossa.

58:49

There is a pointed radial styloid not shown there was involvement of the

58:53

lunate fossa,

58:54

but look at that generalized degeneration of the entire carpus with a

58:59

dorsal facing lunate with osteoarthritic spurs.

59:03

Stage four slack wrist with dorsal and ary segmental

59:07

instability and with a fracture really making it a snack wrist

59:12

rather than a slack wrist. And here it is on the water weighted image.

59:17

Look at that massive proximal capitate migration.

59:21

Ulnar translocation o o of the lunate.

59:24

And now you cannot even see the median nerve. It's right over here.

59:29

It's this flat,

59:30

tiny little pancake that is compressed by the lar

59:35

displacement of the capitate and hammid.

59:39

And look at the thenar eminence. Hypo thenar looks fine.

59:42

The patient virtually has no thenar eminence.

59:45

So end stage carpal tunnel syndrome from end stage class four slack

59:50

wrist. So that concludes our,

59:52

our discussion today of taken you through some basic

59:57

anatomy, some basic tenets of, uh,

60:03

selective imaging sequences like radial and ulnar deviation, pronation,

60:08

supination compound, uh, scaphoid views.

60:11

I took you through the details of the triangular fibrocartilage,

60:15

the Palmer one traumatic classification system,

60:18

the polymer two abutment classification system.

60:21

Then we looked at some intrinsic and extrinsic ligaments and finished with

60:26

some very complex instabilities of the wrist. And with that,

60:29

I'll take some questions.

60:38

All right? Yes. Thank you, uh, for sharing your lecture today, Dr. P Um,

60:42

at this time we open the floor for any questions from our audience. Uh,

60:45

you can submit your questions to Dr. Pomerantz through the q and A feature.

60:50

Uh, Dr. Pomerance,

60:51

would you like me to do my best to redo the questions or can you see them?

60:55

I can see them.

60:56

So U C L is considered part of the T F C or not the TF

61:01

T F C C or not. T F C C is kind of a wastebasket, so everything goes in there.

61:07

So the ulnar collateral ligament is in most circles considered part of the the T

61:12

F C C.

61:13

It's not a critically important structure since it doesn't provide a lot of

61:16

instability. It's usually used as an indirect sign of other things,

61:21

uh, that are happening such as the case that I showed you. So the answer is,

61:25

it is how reliable is various vari variance assessment on M r I.

61:30

Um, doesn't patient positioning affect this? It absolutely does.

61:36

You'll notice in my slides slides, I didn't say ulnar variants positive.

61:41

I said positive variance posture because hand surgeons are like

61:45

neurosurgeons, detail oriented, thank God O C D,

61:50

not to a fault they're O C D, thank God they are. So,

61:54

they are very specific about how they want their variants measured on

61:58

conventional radiography. And that is why I use the term posture. However,

62:03

you have an obligation to use a little bit of common sense.

62:06

So let's say you're more than eight millimeters distal to the radius with your

62:10

ulna, look at what's happening around you. If the T F C is thinned,

62:14

if there's fluid in the radial nerve articulation, if there is luon malacia,

62:19

you have an obligation to call out that ulnar positive variance

62:24

posture to protect yourself and say that the patient has secondary signs

62:29

of ulnar lunate abutment syndrome.

62:31

So I absolutely use the secondary signs to put myself on

62:36

sound footing as it relates to variants when dealing with hand surgeons

62:41

who have very strict criteria for such. Um,

62:45

which protocol would you recommend when evaluating a vitality of bone on M R I?

62:49

For instance,

62:50

in the case of keen box disease or scavo fracture is T one fat sat

62:55

before and after contrast injection sufficient,

62:58

or the only examination that can get the optimal and realistic results?

63:02

When we use profusion sequences? Well, first of all,

63:05

I wouldn't do profusion imaging if I have a uniform or nearly uniform

63:10

black slightly collapsed or markedly collapsed, you know, lunate.

63:15

Now if somebody, you know,

63:16

has a normal size lunate and it it's an indeterminate keen box case

63:21

or they're trying to determine how much is viable and how much is not viable,

63:27

which wouldn't be in a uniform black lunate,

63:30

then I will do dynamic contrast imaging,

63:33

just as I might do with say a breast m r i,

63:37

I'll do very fast fat suppression, gradient echo imaging and um,

63:42

you know, maybe a slice every three seconds or so. You don't have to be too,

63:45

too quick with it. And look at how the lunate peruses, how often do I do that?

63:50

Maybe two to three times a year.

63:52

I've done it a few times in the scaphoid as well, but, but it isn't,

63:56

it isn't standard practice for me, but that's the best way to do it,

64:01

kind of mimicking the dynamic breast protocol. Next, please.

64:05

Any other question? There's more right there.

64:08

How much physiologic fluid is there in the distal radial ulnar joint?

64:13

I allow a slit. What's a slit a millimeter of fluid.

64:17

There's gonna be some subjectivity there,

64:19

but it's gonna be a very ti a very tiny amount.

64:23

And it's also gonna depend on patient age. For instance,

64:26

if I have a 15 year old, I don't wanna see any fluid there.

64:29

If I have a 50 year old, I'll allow a millimeter of, you know,

64:32

lubricating fluid and, you know, potential overuse and, and so on. You know,

64:37

if, if I'm on the fence, I'm looking at everything else. I'm looking at the,

64:42

the vola and dorsal radio ulnar ligaments. I'm looking at the intrinsics,

64:45

I'm looking at the adjacent, uh,

64:48

radio ulnar cartilage using indirect signs to make that decision.

64:53

Next question. What is the significance of the space of Poirier? Well,

64:57

the space of Poirier is this sort of weakness that occurs between those short

65:02

lar blue ligaments that I drew for you that is kind of right in the middle,

65:06

just volar to the capitate. It is important 'cause it's an area of weakness,

65:11

and when you have these more advanced complex instabilities,

65:15

it will allow the capitate to come forward.

65:18

It'll allow the capitate to drop down and it can contribute to what you saw

65:23

at the end end stage.

65:25

Carpal tunnel syndrome orthopod tells you to look for ulnar collateral

65:30

ligament injury. Where to look for it. And is there any significance? Well,

65:34

I'm not sure, um,

65:36

an experienced hand surgeon would ever order an M R I for that purpose.

65:41

We all know that.

65:41

Do a lot of wrist imaging that the U C L is a flimsy structure.

65:46

It is used by us as an indirect sign of other problems, ret, macular stripping,

65:50

E C U disease and so on.

65:52

But the best place to look for it is where I showed you on higher resolution

65:57

coronal uh, imaging. And it doesn't necessarily matter which sequence,

66:01

although I, I, I see it best on a one to two millimeter fiesta sequence.

66:06

How reliable is T F C C interpretation on films or on scans done in other

66:11

places? Do you end up repeating such scans at your place?

66:15

That's a loaded question. You know, we are a, a tertiary referrals facility,

66:20

so we do get to see and resolve these usually without contrast.

66:25

And, um, MR is extremely reliable, extremely reliable.

66:30

I I hardly ever inject a risk to diagnose A T F C or

66:35

A T F C C tear.

66:37

The most common use of contrast for me is in an equivocal

66:41

LT ligament injury. And that, that is not often a next question, um,

66:47

about DIS and vsi. Uh,

66:49

are there standard angles to measure the position of the lunate and scaphoid and

66:54

capitate bones? There are. If you email me, I'll send you those angles. My,

66:59

my pen is not working. But as a general rule of thumb,

67:02

I like the scaphoid to have about a 45 to 60 degree position

67:07

relative to the vertical. So if I start to see the sca,

67:11

I dip below 45 degrees and start approaching the horizontal,

67:15

then I know I have rotatory displacement regarding DSI and vsi.

67:21

That's a little more easy. However, if the technologist puts the,

67:25

the hand in the scanner and they do this, they owner deviate,

67:29

you are going to create a disci posture appearance,

67:33

so-called pseudo disse.

67:36

So make sure that your wrist is absolutely straight and if

67:40

it is,

67:41

your lunate should be pointed straight up towards the capitate and straight up

67:45

towards the base of the third metacarpal. Um,

67:51

let's see. Question about the E C U.

67:54

Is the E C U part of the T F C C?

67:57

It is as is its sub sheet.

68:02

Alright, are there any other questions? 1.5 versus three T,

68:05

which one is preferable? They're both fine. Absolutely.

68:10

And you can scan with low field in the wrist because you can get the hand in the

68:14

center of the magnet bore. So if you can do the right sequences, stern,

68:18

then section gradient echo imaging, Sarge, you know,

68:22

one two millimeter slices.

68:24

You absolutely can image the wrist at low field as low as 0.18 Tesla.

68:30

Okay, I think I have answered all the questions.

68:34

Doesn't patient positioning affect the ability to assess dsi?

68:37

I think I answered that one. You absolutely need to have the risks straight.

68:41

If you owner deviate, you're gonna create pseudo dsi. If you radial deviate,

68:45

you're gonna create pseudo vsi. Alright,

68:50

I think that's about it.

68:51

Thank you for your thoughtful questions and I hope to see you all

68:56

in September for the combined, uh, Resnick,

69:00

Pomerance Chung and Colleagues course. Uh, we're looking forward to seeing you.

69:05

Have a great day.

69:06

Thank you so much again, Dr. Pomerance. Uh,

69:09

and thank you to everyone for your questions and participating in our noon

69:13

conference.

69:14

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69:29

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69:33

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