Peter and Mario from the Mayo Clinic. Their clinic have had extensive experience in the basic science and clinical practice of vascularized bone grafts. Peter, would you come along and tell us a bit more about it? Thank you, Peter. Thanks. Well, it's great to be here. And perhaps some of you were at some of the afternoon sessions. I think that they're also relevant to keen box disease as we think about it. So we were at the, how many of you were at the Hand Club Smackdown thing? Yeah, a lot of people went. That was pretty good fun. Of course, I was in my group, lost last year, the Hand Forum to the New Millennium Club, and we got skunked by a case where we basically treated the x-ray, not the patient. And I think that's an important message to take in keen box disease. And how many people heard Peter Pronovost talk? So some people were at that, too. Very interesting talk. He's from Johns Hopkins, of course. And Johns Hopkins is famous for many things, but also for some very famous teachers, including Sir William Osler, who famously said, it's better to know the patient who has the disease than it is to know the disease the patient has. And again, I think it's relevant to keen box disease because, as you can see, it's very complex. I mean, you have the status of the shape of the lunate bone, the blood supply to the lunate bone, whether the lunate is fractured or not, whether the articular cartilage is intact or damaged in some way, and is the damage a kind of a diffuse damage, or is it focal from a fracture? All those relate to what the x-ray looks like, what the image looks like. But we also have to factor in, as well, how the patient feels. And I think that's – I think it's important to bear in mind because sometimes you have really bad images of a patient who's not particularly bothered, and that might drive you in one direction. Certainly the images are very, very helpful in telling you what might be possible to do and might not be possible to do if the patient is bothered. But I think we just need to kind of keep the focus, again, on the patient that comes in to see us. So I'm going to talk a little bit about revascularization. This is a procedure that's been described. And the rationale, of course, is this is a condition of avascular necrosis, so why not just put back the circulation? But, you know, the question is – and we've just heard some conversation here in the last couple talks – is the outcome affected by the initial vascularity of the lunate bone, whether it's dead or dying? You know, this is the MRI picture. Whether it's whole bone or partial bone, we haven't talked about that very much. But does that make a difference? What if half the bone is stone-cold dead and the other half is completely normal? I mean, does that make a difference as opposed to having this transition zone, for example, of revascularization that's occurring? Because we can see those kinds of things as well. And I don't think we really know the answers to that. So the common indications for revascularization are you have an intact lunate. If the lunate is split in half and the dorsal half is someplace on the dorsal side of the wrist and the palmar half is on the palmar side of the wrist and there's three or four millimeters or more in between the two pieces, probably revascularization is not going to be a real good option for you. But again, intact lunate is kind of a term of art because when we first started talking about these things, we didn't have such good imaging. And now that we have really good imaging and we can, of course, look on MRI, excuse me, arthroscopically as well, we can see infractions in the surface of the cartilage and we can see maybe the cartilage envelope is intact but inside the bone is cracked. I mean, to what extent does that modify the prognosis for revascularization? We really don't know. Most people talk about, well, a little bit of collapse is okay from proximal to distal. Maybe if you have an undisplaced fracture like you can see here and there's really two fractures here. You can see there's a crack here and there's a crack here. You know, maybe that's okay. As I say, it's kind of there's a lot of art that goes into deciding what you might try in these various patients. And, of course, you have other choices in these kinds of patients too. As David pointed out, you know, you could shorten the capitate. You could shorten the radius. There are other options for these same stages of disease. And do you go into, do you try to reinflate the lunate if you have some lunate collapse and that's causing the secondary carpal instability? We can have a talk about is that carpal instability or is it just that the carpus is shortened and so the bones don't have the normal relationship to each other because the whole space between, say, the metacarpals and the distal radius is now shorter than normal because the lunate has collapsed. But is that instability or is that malposition? And, you know, of course you can do the joint, you can do a revascularization with some sort of joint leveling procedure. You can do it with a capitate shortening. You could do it with a radial shortening. So or lengthening. And so, you know, how do you make those decisions? And there really aren't any good answers. So you can probably stop paying attention now because we really don't know. All we have based in the literature is some case series of some people who tried it and their patients did okay. But we also know that some people tried, you know, joint leveling and their patients did okay. And some people put their patients in casts and their patients did okay. And some people did other things and the patients did okay. And there's that fellow down in Argentina who just drills a hole in the distal radius and calls it a day and they do okay. And so, you know, we really don't know for sure whether it's the treatment that's giving the benefit or whether it's a treatment or any treatment, something that does it. So because revascularization can occur by a lot of means, as I say, and that's one of the theories about that drilling a hole, for example, in the distal radius increases the blood supply in the general area. And maybe that is enough to cause revascularization without actually taking a blood vessel from point A and sticking it into point B. So and of course osteotomies do the same thing. Instead of drilling a hole, you actually cut the bone. That obviously creates a fracture and that causes increased blood supply in the distal radius, excuse me, in the region of the carpus. And so maybe it doesn't matter so much what you do to marshal stem cells and blood vessels to come into the area. It's just do you do it by some means or another? So as I say, so the literature talks about a variety of different things. And so here's some different choices here. You can take different vascular pedicles. You have the dorsal intermetacarpal arteries, of course, that you can take. Again, if the lunate's intact, you can drill a hole in the lunate. You can stick an artery in there with or without some bone chips that you can fetch from the distal radius or wherever you like. And as I say, in selected cases that you can find case reports that say that these patients do okay. But it's not always so clear because there's no prospect of randomized trials where they said, well, let's try this with the bone graft. Let's try it without the bone graft. Let's compare it to joint leveling. Let's compare it to just drilling a hole in the distal radius. There's no study like that. You'd probably need hundreds of patients and we don't have hundreds of patients. It's not that common of a condition. Now maybe if we, you know, all the hand surgeons in the world would get together and decide to randomize their patients into some gigantic trial, maybe we'd get that answer. But so far we don't. So Hori was one of the first to talk about using vascularized pedicles back in 1979, second dorsal metacarpal artery. And again, so this is similar to the picture you saw before. And, you know, you can see in animal models that this definitely works or if you go back and do second biopsies, you can see that there is revascularization that occurs. But as you saw a picture from Dave Lickerman, revascularization occurred in that one patient but doing nothing, just waiting and watching and it revascularized. So we don't really know whether this has a therapeutic effect and exactly what the therapeutic effect is because we really haven't done the good studies. And we can do some of these things in animals. Alan Bishop has done some work in our own place taking animal bones and encasing them in methacrylate and so forth, making sure that they're dead. And the problem though is that in animal models, their carpal bones revascularize like crazy, no matter what you do. And so you really can't use, there's not really an apt animal model for avascular necrosis that we can rely upon. And this is one of the reasons why people don't know very much about it. You know, there's been models, again, for avascular necrosis of the hip is a common problem. It suffers from the same problems. It's very, very difficult to create an animal model that is relevant to the actual human condition because animals don't seem to get this particular problem that often. So you can certainly do that. You can put an artery with a vein, if you like. To my reported 51 patients, that's a fair amount, a five-year follow-up, all different stages of Keenbox disease. Some of them, though, had other things done, STT fusion. Almost all had pain relief. Their strength went up. And, you know, they had, but even though 98% had pain relief, only 67%, you know, kind of reported really good outcomes. A little bit more with the STT fusion, and the x-rays progressed. So what did the revascularization actually do? I don't know that we know. And as my colleague Alan Bishop has designed this, different kinds of vascular pedicles that you can take from the dorsal aspect of the distal radius. So this can also work to, as Steve Moran wrote up, 26 patients, 31-month follow-up, stage 2 to 3B. Basically scraping out all the dead bone, leaving a cartilage shell, putting in this vascularized bone plug, if you will, with additional cancellous bone. Range of motion, a little bit less than normal. Grip strength, a little bit less than normal. But, and again, 92% relief of pain, 85% satisfaction. But what does that mean in context? Because basically you can take other treatments for Keenbox disease and get similar outcomes. So what does it tell you about when to use this procedure, why to use this procedure, when to use something else instead? I think, again, we really don't have the good answer. And I don't know what, how to get it other than, as I say, these prospective randomized trials that seem beyond our limits because of the small number of patients that each of us individually see. And again, no radiographic improvement or progression, though, for lunate height, carpal index, or scapholunate angle. There did appear to be MRI evidence of revascularization, so that's good. And the patients seem to do less well when the lunate's revascularized, which suggests that revascularization is a good thing. And so there's some circumstantial or suggestive evidence that revascularization is useful. But again, not as good as we might like. And this is a little trick that Alan and Steve have reported, which is basically you put the wrist in alternate deviation, you put a couple K wires between the scaphoid and the capitate, and then when you bring the wrist back into neutral position, it puts a little distraction across the mid-carpal joint, unloads the lunate a little bit, and maybe that's not a bad thing to do. When you do your revascularization, you can see the little hole here where the hole is to bring the blood vessels into the lunate. Maybe it's not a bad idea to leave the wrist distracted like that for six weeks or so, and it's a lot easier to do this than it is to, say, put on an external fixator. So free vascularized bone graft. So here's taking basically a hunk of Iliac crest with its blood supply. This seems a little bit extreme, especially since there are lots of local choices, but it's also been reported. And this may be one of those articles, like if you have a hammer, everything looks like a nail, so you know how to do this Iliac crest bone graft, so you take it from there as opposed to from a local pedicle. But it can work. It can work. They plug it into the ulnar artery, put an external fixator on, and the one difference is you can basically shape something that really looks about the size and shape of the lunate, which you certainly can't do from the distal radius. And so this is another potential possibility. And 18 patients with an average 13-year follow-up, 90 percent revascularized. This one did seem to help carpal height. And range of motion, again, remains less than normal. Grip significantly less than maybe some of those previous studies I showed you. Dash score, though, quite good. Zero and a dash zero is good. A hundred is bad. So eight is not that far off of normal. And only two patients with poor results. So again, another possibility. When and how and why do you pick this choice as opposed to others, though? I can't really give you good suggestions. Here's another one, capitate shortening. Remember I mentioned doing that as another option. And say here's one with ulna plus. Tom Trumbull reported. Again, you can do, as I said, you can do this procedure in association with joint leveling, whether it's a mid-carpal leveling or a distal forearm leveling procedure. And he looked at 14 patients, three and a half-year follow-up. Grip strength improved, but again, less than normal. Range of motion still not normal. Patients were satisfied. Most went back to work. Seemed to do better with earlier stages of Keenbox disease. Most people don't talk about it in these studies, though. Again, what did the CT scan look like? What did the MRI look like? You know, what were the, was the lunate fracture or not? So in summary, I guess I would say that revascularization is certainly a reasonable option when the lunate is structurally intact. And that's a term of art. You get to choose what is meant by structurally intact. There is the potential to reinflate a collapsed lunate, and there certainly are case reports of that being successfully accomplished. There are many ways to do it. You can use a vascular bundle. You can take a pedicle bone graft. You can use a free vascularized bone graft from the iliac crest. So there are a variety of ways to do it, and they all seem to work similarly. But how that stacks up in the long run with other treatments, if you had exact the same indications, I think, again, remains one of, to join Mark Garcia-Elias' many continued ongoing questions about Keenbox disease. Thank you for your attention.

vascularized bone grafts

Keenbox disease

revascularization

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long-term outcomes