0:00

So we finished off with a avascular necrosis in the

0:03

setting of revascularization.

0:05

Gonna move on to another clinical conundrum,

0:07

which is the charco foot.

0:09

As with a lot of things in MSK,

0:11

there are two flavors of this.

0:13

There's an acute phase, which can be easily mistaken

0:17

for an infected foot because it's very red

0:20

and swollen and painful.

0:22

This is an example here of a more chronic, uh, involvement

0:26

of neuropathic foot in that it targets the two main areas,

0:30

the metatarsal heads, as well as the midfoot.

0:34

And what we're seeing here on both the Mr Sagittal images is

0:39

fragmentation and edema around the metatarsal heads.

0:43

Those, those, um, those two metatarsal heads, the second

0:47

and the third are fractured and fragmented

0:51

and leading to this kind of, um,

0:53

soft tissue abnormality in the four foot.

0:57

As we turn our attention more proximally,

1:00

we can see even more Aussie destruction

1:03

of the navicular and portions of the q and e forms

1:07

and even the OID bones, um, that are,

1:10

are really nicely seen on the corona, sorry, the axial, um,

1:15

image here with patchy areas of marrow edema.

1:20

So this is an example of a chronic charco foot,

1:23

which radiographically we'd like to talk about all the Ds,

1:26

the increased density dislocation, um, a debris

1:30

and disorganization.

1:34

This is a case

1:35

where the Charcot foot has subsequently gotten infected.

1:40

So we use, again, same kind of, uh, tools

1:43

to help us figure out is this really infected

1:46

on the radiographic exam here?

1:49

We can actually appreciate these air within the

1:52

second metatarsal head.

1:54

There's not a whole lot of bony fragmentation,

1:55

but there's no question there's air there.

1:58

As we look at the, um, the UHM R images, we see pre

2:03

and post contrast, um,

2:04

images showing this collection along the superior aspect

2:08

of the metatarsal phalangeal joint with signal alteration

2:12

of the proximal phalanx confirming the presence

2:15

of osteomyelitis

2:16

and septic arthritis in this patient

2:18

with a neuropathic foot.

2:20

We can see some of those neuropathic changes in the midfoot

2:23

with the, uh, frank mirror edema

2:25

and some bony fragmentation as well.

2:28

So kind of same features that we're gonna be using

2:32

to determine high likelihood

2:35

of osteomyelitis versus low likelihood of osteomyelitis.

2:39

The next couple of slides goes through a few

2:42

of the classic findings of charco foot

2:45

or neuropathic osteoarthropathy on the top image.

2:48

Here we see the marrow edema centered at the midfoot

2:52

with some associated cystic changes

2:55

on the CT image on the bottom right.

2:57

We appreciate more cystic changes in a peri articular

3:02

distribution and maybe even a couple Aussie erosions that,

3:06

uh, do not have a complete subc chondral bone uh, border.

3:14

Trying to advance the slides. What about this one?

3:18

So this is an, this is another case of a patient

3:21

with neuropathic osteoarthropathy

3:24

and this time he has this very large multi lobulated

3:28

collection along the side of the ankle here

3:31

and superficial to the flexor tendons.

3:34

And I'll tell you that this was biopsied multiple times

3:37

and had two negative cultures.

3:40

As we look at the rest of this patient's foot, we can see

3:44

that there is extensive bone destruction, complete collapse

3:47

of the navicular, even collapse of portions of the q

3:50

and a form back in 2019.

3:52

Um, and this is a, this is an example of, um, a charco,

3:58

uh, neuropathic foot that subsequently did progress

4:03

in its neuropathy

4:04

and bone fragmentation in 2020,

4:07

showing the marrow edema involving the Alis

4:09

and even further collapse of the midfoot itself.

4:14

And this is an example where I really like

4:16

to see the radiographs and watch it like a bad movie, right?

4:20

So here you can see navicular is still present.

4:22

Q eForms are relatively unscathed except for these erosions

4:26

that are in between the navicular and the Q eForms.

4:29

And as we progress over time, we can really see that kind

4:32

of, uh, bony destruction that collapses all

4:36

of those QA forms as we get reach, um, the, the June

4:39

of 2020 year.

4:42

One more example of

4:43

how charco arthropathy can progress this time in 20 to 14.

4:47

So we've had a little bit of a longer period of time

4:50

where we can see all the bony fragmentation,

4:52

the subc chondral cystic change debris sitting in the

4:56

region of a midfoot.

4:58

And you'll notice in this particular case,

5:00

now the Alis is a complete portions

5:03

of the Alis are completely gone,

5:05

but we still have the presence

5:06

of these subc chondral cysts, uh, in this place.

5:09

So this is, uh, just progression of charco arthropathy

5:14

itself rather than a superimposed infection.

5:18

So we mentioned a couple of things

5:20

that can help us differentiate it.

5:22

Um, and those are reiterated here and here

5:26

and just a chart to again,

5:27

help you in case you find yourself in a bind

5:30

and trying to, uh, trying to differentiate

5:32

between osteomyelitis versus super

5:35

and post osteomyelitis on, um, short code foot.

5:39

This is a nice example from one

5:41

of my colleagues over at UCSD showing

5:43

how diffusion weighted imaging can help us, uh,

5:46

problem solve, especially in patients

5:48

who cannot get intravenous contrast.

5:51

Um, and this is a patient who had this, uh,

5:54

resection pre four and

5:56

They're concerned about osteomyelitis.

5:59

One more time. Here's the T one weighted sequence,

6:01

which I think is already pretty diagnostic with the kind

6:05

of homogeneous signal alteration.

6:07

However, this is the, um, the diffusion weighted sequences

6:11

and then the a DC map showing

6:13

that there is restricted diffusion here

6:15

and that it is still low signal intensity on the a DC map so

6:19

that it is true, uh, restricted diffusion.