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Dr.P and Dr. Stern

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3 00:00:01,680 --> 00:00:05,890 here talking about a gal who's 63 years old

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and she had carpal tunnel surgery three years

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previously and now is complaining of diffused

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wrist pain, radiating up and down the arm.

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We've got three coronal series here.

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One, a fat-suppressed,

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water weighted image, proton density.

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In the middle, we've got the thin section,

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cartilage-sensitive gradient echo image.

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And on the right, we've got the

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anatomic, fat-weighted image.

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T1-weighted image.

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There's obviously some erosions and arthropathy here

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at the capitate-hamate articulation, but the finding

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that you're going to see as we scroll, and we've

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got some arrows on several of these findings,

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is the deformed, collapsed, irregular, signal-altered

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lunate, with some changes around the lunate as well.

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So when you have a patient who has

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sustained a condition like this,

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which is obviously the necrosis of the lunate.

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What things are important to you?

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What do you need to know from us?

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I mean, this is a plain film diagnosis.

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But there are some other things going on.

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The arthritis, the SL interval isn't normal.

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The LT interval is breaking down.

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Uh, there's probably a little

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bit of ulnar. What matters to you?

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Well, there are a number of things that, uh,

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matter depending on, uh, how advanced the disease is.

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So, we're primarily interested

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in the integrity of the lunate.

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Uh, it's felt initially, uh, that

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there may just be edema in the lunate

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and it may be, uh, perfectly intact.

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Uh, over time, the, uh, lunate will, uh, and it's

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usually a coronal, coronal midplane, uh, fracture.

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Uh, then as time progresses,

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you see degenerative changes.

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You can tell in this case, or at least I think that,

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uh, this lady's had this for a fairly long amount

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of time because you can see some beaking of the

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radial styloid process, uh, which I think, uh, is

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probably a reflection of some radioscapular arthritis.

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I would defer to you as to whether or

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not I'm making a true statement or not.

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The only thing that the MR makes a little bit

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difficult is we always look at the ulnar variance.

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About 80 percent of people

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have a negative ulnar variance.

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That is, the distal, uh, surface of the ulna should

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be parallel with the lunate distal radius here.

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It's a positive variance, and I would bet

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that this image was taken in pronation

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which artificially, uh, lengthens the ulna.

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I mean sometimes we'll, you know, we'll

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61 00:02:44,399 --> 00:02:46,750 get a clenched fist view even on MRI.

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And it'll be surprising,

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you know, the lunate will jut forward.

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Occasionally, we'll see a kind of an

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excessive conical or forward conical ulna.

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And even though the variance is neutral,

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when the patient is in supination or the patient has a

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clenched fist view, they get, uh, signs of abutment.

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But, but typically, uh, Keenbox,

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negative variance, right?

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Yes.

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That's, that's the typical thing.

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The other thing that we don't, or at least I'm not

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appreciating that much, if you had some sagittal images

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it might help, but usually, uh, as when the lunate

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fractures again, the capitate migrates proximally,

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uh, and the scaphoid will tend to go into flexion.

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In other words, it will become more vertical with

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respect to the, uh, long axis of the forearm.

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So I think that's exactly what's happening here.

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Here's the capitate on the left.

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You can see it's kind of pistoning backwards.

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The lunate is collapsed and

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fragmenting in multiple areas.

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And, uh, what were some of the other, uh, the

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flexion of the scaphoid was the other issue.

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And sure, the, uh, typically just eyeballing it, you

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know, the scaphoid would sit at about this angle.

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So you can see it's starting to kind of fall over

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or rotate, as you said, definitely going into flex.

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So that's happening.

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And then so

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normally the, uh, just from a normal

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measurement, the, uh, angle between the, uh, uh,

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actually the scaphoid and lunate is about 47

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degrees and, uh, with a maximum of 60 degrees.

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So here it's probably in the

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75 degree, uh, neighborhood.

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So you're talking about an angle like this, right?

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Yep.

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So, typically, when the lunate, when the

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scaphoid flexes, this angle is going to increase.

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Yes,

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the scaphoid flexes, and you see the

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lunate reciprocally, reciprocally extends.

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That's the, uh, ligament.

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Generally, there's an attenuation of the ligament

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between the scaphoid and lunate, and the helicoidal

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articulation between the, uh, hamate and the

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triquetrum drives the lunate into extension.

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What do you mean by that?

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The lunate and extension for the imagers out there.

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Yeah, so lunate and extension basically is DISSI,

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uh, dorsal intercalated segmental instability.

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Uh, it's a little easier to see on

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a plain film than it is on an MRI.

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But the lunate Uh, normally sits, uh, in the

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head of the capitate looking straight ahead.

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Uh, if it starts to look dorsal more than

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15 degrees off the long axis, uh, that's

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an indication that, uh, it's in extension.

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So it looks something like

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this, kind of a dorsal facing.

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That's exactly right.

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Yeah.

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Yeah.

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So the combination would be dorsal, slight

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dorsal facing lunate and a flexed capitate.

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Uh, scaphoid.

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Let me ask you about Exactly.

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Let me ask you about these ligaments, because

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that's probably something you can't You

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can appreciate on plain film the widening,

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but this, this ligament is breaking down.

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I mean, it should be a nice,

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black, triangular mustache.

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And it looks like a mustache with shaving cream on it.

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It looks like a mushy thing right there.

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And, uh, that's allowing the lunate

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to drift into an ulnar position.

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Uh, does that change the management in any way?

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And the LT ligament is breaking down too.

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Yeah, that's,

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that's a little surprising.

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Usually the LT, uh, stays intact.

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But, uh, sure.

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The, uh, this just, just

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looking, uh, taking a step back.

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This lunate is shattered.

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I mean, it's, uh, it is a non

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reconstructible situation.

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So from a clinical standpoint,

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uh, there's not, not a lot.

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There, there are just lots and lots of

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procedures that are done for Keenbach disease.

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But, uh, from a clinical standpoint, I think most, uh,

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clinicians would make no effort to salvage the lunate.

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It would, uh, probably end up that the

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patient would have, uh, at this age,

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a so-called proximal carpectomy, removal of

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the scaphoid, lunate, and triquetrum.

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So all three would come out?

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164 00:06:57,735 --> 00:06:58,025 Yeah.

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Wow.

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Okay.

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Dr. P and Dr. Stern out.