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CME Diabetic Foot

The Charcot Foot and Ankle

Guido LaPorta, DPM, MS

Guido LaPorta, DPM, MS discusses the different stages of Charcot deformity. Dr LaPorta reviews classification of Charcot deformities and the appropriate treatment options for each. He reviews radiographic evidence of Charcot as well as surgical technique for repair.

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Goals and Objectives
  1. Discuss the history and the pathogenesis of Charcot deformities
  2. Recognize the different classifications of Charcot deformity
  3. Understand medical and surgical management for acute onset Charcot foot
  4. Understand the management of chronic Charcot deformity including medical and surgical options
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  • CPME (Credits: 0.75)

    PRESENT eLearning Systems, LLC is approved by the Council on Podiatric Medical Education as a provider of continuing education in podiatric medicine.

    PRESENT eLearning Systems, LLC has approved this activity for a maximum of 0.75 continuing education contact hours.

    Release Date: 03/16/2018 Expiration Date: 12/31/2018

  • Author
  • Guido LaPorta, DPM, MS

    Director Podiatric Medical Education
    Community Medical Center
    Scranton, PA

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  • Lecture Transcript
  • Male Speaker: Thanks, Bob. I'm going to discuss Charcot foot and ankle. There are a number of, I think, general principles that we need to talk about and I'm going to concentrate on some of the surgical principles that I find extremely important. My biography, my disclosures. And the goals and objectives here will be to talk about the surgical treatment and the difference between limb preservation and limb salvage. So the question is, can we save this leg. You know, we see problems like this quite frequently in conjunction with Charcot ankle. And the second question I'm going to ask is, how does this happen. You'll be happy to know that I don't know the answer to either question. And I'm still trying to find out what the markers are that would help me determine that. But what we have managed to do, and I've been incredibly fortunate along this line, maybe some of my patients haven't, but I have been and that this was an early interest of mine. And probably, over the last 12 years, we've been involved in the reconstruction of close to 800 Charcot feet. We've made mistakes along the way, but it has helped us to at least hone in our thought process as to what, in fact, we should be looking at. I mentioned early the concept of SAUDI, S-A-U-D-I, and it's kind of the way I liked to talk to residents about this because everyone wants the definitive answer, what do I do for Charcot foot. Well, it's, unfortunately, not that simple. Many of the talks that you've heard earlier certainly highlight that point. So when they ask me that question, my answer to them is, how about going through an acronym SAUDI. What's the stability of the foot, what's the activity of the foot, meaning is it acute, chronic, or somewhere in between. Is there an ulcer or is there a previous ulcer. Is there deformity, is that deformity stable or run stable and is there an infection and is the infection soft tissue or bone. And if you can provide me with some information about those parameters, then maybe we can come to a discussion about what to do for a particular patient who presents with Charcot neuroarthropathy. So let's talk about some management strategies. And certainly, the first one we need to talk about is the acute onset Charcot deformity or the active Charcot deformity. And the first thing I want to know about is the alignment acceptable or is there dislocation or possibly even fractured dislocation. If there's acceptable alignment in general, our goal is to halt the process and this usually is a non-weightbearing approach to this particular deformity with some type of mechanism to reduce edema and/or swelling. And the non- weightbearing cast immobilization or total contact cast for a period of time, which usually ends up being longer than most of the published parameters that I see, we're looking in the neighborhood of three months or longer in order to calm this down. But what happens if there is dislocation, can you put up with dislocation, is there a fracture dislocation, is an ulcer present because of that particular trauma. Well, you usually fall into one or two categories. You can do an open reduction with an arthrodesis, which quite frankly, is very rare in our institution or you can do a closed reduction with or without percutaneous pins, which is usually followed by plaster. A technique I learned many years ago, pins and plaster technique for various fracture dislocations. So that starts the discussion with the acute onset Charcot deformity. How about the chronic deformity?

    [00:05:00]

    Well, the chronic deformity at least gives you some time to think about this and quite basically, you can break this down into either a stable or an unstable deformity. If you have a stable chronic Charcot and there happens to be an ulcer or a pre-ulcerative state, you can consider exostectomy. But I would caution you that in some instances in doing our exostectomy or planing of the plantar surface of the foot, we have rendered a stable foot unstable. And I think some of the reason for that is that, what we're doing is removing the exuberant bone that was formed in order to stabilize an unstable joint. And if in fact, we then remove that bone, we're dealing with an unstable situation which will require more invasive approach. Consequently, all of our patients who are undergoing a planing or exostectomy are, in fact, informed that they may have to undergo a fusion right at the time of the exostectomy and it may be necessary to fuse the underlying joint. If they're unstable, these patients are usually a candidate for reconstruction and the reconstruction can be done in one of two ways. You can do it acutely, which means you take out the appropriate wedges, treat the soft tissue infection, bone infection, right pad on the table or you can do it gradually. And gradual correction or reconstruction has the major advantage that it preserves to a great extent, the length of the foot so that there is symmetry between the two extremities. I don't think either way is right or wrong. It's just the different approach to that. So classifications are somewhat helpful and there are many. Eichenholtz, the temporal classification. It has been recently suggested that instead of using that that we refer to it as active versus inactive. Sanders and Frykberg have a classification, which has probably been used by podiatry more than any others. Brodsky and the Schoene classification. And when you break all of these down, they're basically anatomical classifications. Schoene attempted to apply some elements of the type of treatment that should be used and the severity which hopefully would give us a better idea about prognosis. Now, this is a very busy slide, which you probably can't read, but it basically breaks down any one of these anatomical classifications and to somewhat of a flowchart of what, in fact, you should be thinking of. I should point out that when I see an ankle Charcot, it usually occurs after a traumatic [indecipherable] [00:08:24] unless the nexus is a hindfoot infection which infects the talus leading to either osteomyelitis or AVN with collapse. I'm never quite sure what the ideology is, but I can tell you that I agree with the consensus panel that ankle Charcot is probably as close to a primary indication for surgical intervention as there is in the foot. The inability to stabilize the ankle with conventional bracing is very prevalent and these patients continue to get into problems as they progress. So let's look at this system and this is the Schoene classification system. And based on this, this is a picture that I give to most residents. And the reason for that is that, as you go down the anatomic area, you're dealing with the more hindfoot application of Charcot. And as you go across A, B and C, you're going across the foot from medial to lateral column. And what I like to point out is that, as we go down from 1 to 4 and go across from A to C, that we have more and more indication for the use of external fixation as opposed to internal fixation.

    [00:10:04]

    Now, this is without infections. So even without infection, I believe that there are certain presentations of Charcot that demand the use of external fixation for multiplane correction. So if you look at this presentation, you can see that the various joints that become involved with midfoot Charcot. This does not include hindfoot Charcot. And the most common presentation in hindfoot Charcot to me is a dislocation of the subtalar joint followed closely by AVN or osteomyelitis of the talus. So type 1 in most classifications is a Lisfranc joint involvement. And this involvement gets your attention very quick. And the reason it does is because the collapse that occurs, either by comminution and dissolution of bone or by dislocation of the joint causes a rapid reduction in the vault of the arch. And this can take on many forms and look many different ways, they can be obvious such as this or they can be subtle such as this. And this classification will then work its way across Lisfranc joint. And once it gets into the lateral 3 metatarsals, the stability of the arch is significantly affected and you begin to form severe abduction of the foot and a total dissolution of the forefoot. And certainly, what you see and what you're trying to prevent is this rocker bottom deformity which places the foot at risk. One of the reasons that it gets your attention very quickly is that it quickly forms an ulcer. And in the Lisfranc joint application, because it's so far distal in the arch, the weight bearing pressure on the arch will form an ulcer very quickly. And if you do pressure studies, you will note that those areas are extremely loaded with pressure and you can see the different types of ulcers as you progress across to the lateral Lisfranc joint. The ulcer doesn't change position. It just increases in size. So this meatal ulcer can occur with a midtarsal joint and/or a Lisfranc joint. The only thing that changes is its position. And here, such an example of a medial column presentation with ulcer and this was excised acutely as was the underlying fibrosis. And this shows you how far back I go on this. This is at least an 11-year-old case where the ACE-Fischer device was used in order to reconstruct this. And what we did was combine a plantar plate on the medial column followed by neutralization with this ACE-Fischer device. And in this particular case, it comes out to a very good functional result. And I really like the term functional restoration because I think that's, in fact, what we're actually accomplishing here. So this brings up the discussion. Well, if it's just a medial column involvement, can you just use a plantar plate and in fact, you can. Plantar plating is a very, I think, useful technique. As you can see, it requires a little bit more of a soft tissue invasive approach in order to place that plate on the plantar aspect of the medial column and the rationale behind that is that, if this arch is going to fail, it's going to fail on the plantar expect and consequently, that's the tension side of the bone. So that if, in fact, you're going to use a tension plate or a tension band, the best place to put it would be on the bottom. If you're going to use it on top, then you need to pre-stress it so that you can press the plantar aspect. If abduction is your primary deformity, you may want to consider placing it on the medial aspect of the column.

    [00:15:00]

    So as we move back into type 2 and we talk about navicular cuneiform, this is an interesting presentation. You will note that as you go and progress in time, that this navicular cuneiform Charcot actually goes intercuneiform joint and then out the lateral side of the Lisfranc articulation. This gets us in trouble because what happens is that this patient does not form an early ulcer. These patient collapses, collapses, collapses and you may get a false sense of security and that you're preventing an ulcer. But the only reason it doesn't get an ulcer quickly is that the primary collapse is farther back in the vault of the arch and consequently, it takes longer to form. What you have to decide as a clinician is how long you're going to allow it to go that way especially if it's progressing across the midfoot because once the lateral 3 metatarsals are involved, then you get the rocker bottom deformity and you then get the plantar pressure increased and the inevitable ulcer. So this require a little bit more of an involvement here because you not only have the rocker bottom deformity, but you begin to see a significant more equinus developing in the hindfoot secondary to the collapse. The calcaneal inclination angle becomes much more plantigrade. And if this is a long standing deformity, you have no choice here as to whether or not you should do a posterior muscle group lengthening. This almost becomes a requirement for these types of deformities. Again, abduction is part of this as is medial luxation or even dislocation of the medial cuneiform. And once that occurs, then reconstructing this foot becomes very difficult. So the job here is to intervene early to prevent this from happening. As I mentioned, the presentation in type 2 Charcot is usually a lateral ulcer and it occurs late during the formative stages. You can see any one of a number of different ulcer patterns. It starts lateral. You can present with two ulcers, medial and lateral or one large ulcer like in Lisfranc, only farther posterior in the foot. Many times because the ulcer has been present for such a long period of time, you're dealing with either infection or dissolution of the bone in the midfoot and many times, this will require resection of the involved area followed by either internal or external fixation. I am a big fan of combining both of these technologies. I think they're complimentary. I don't really feel that they are at odds with each other. And here, you can see beaming protected by a neutralization frame which allows the patient to at least bear some weight on the foot for nothing else than transfer and daily activities around the house. Here is another navicular cuneiform in which your plantar plate was utilized along with the subtalar joint fusion. So the question might be, why would you do a subtalar joint fusion in a navicular cuneiform or grade 2 Charcot. And the answer is that, usually as a compensatory mechanism in these types of feet, the heel assumes a very varus position. And consequently, just locking up the medial column doesn't improve the ability of the patient to have a plantigrade foot. You need to produce a plantigrade foot. And many times, the only way you can do that is by doing a corrective arthrodesis of the subtalar joint. And I emphasize arthrodesis because corrective osteotomities of these tarsal bones do not heal very well and in fact, you can create additional problems.

    [00:20:04]

    We also use some innovative approaches for locking up the medial column. This is a fibular plate, which I use when I'm doing multiple joints in the medial column. One of the reasons is that you can see that cluster of three screws proximally which engages the talar head very well. And then I simply change the length of the plate depending on how many joints that I am going to fuse. This is a locking plate which also helps. It's also a very low profile plate and it functions very well on the medial column. What you want to try and avoid is someone with all good intentions fusing these joints and using inadequate internal fixation. It's very difficult to get a good result your first time in. It's nearly impossible to do it your second and third time in. So the fixation needs to be, not just adequate, it needs to be robust so that recurrences like this don't occur because of inadequate fixation. Recurrences will occur based on the nature of this disease process. You don't need to add to your problems by doing an inadequate job. So this first time in is then needed to be repaired this way, which gives a very good functional restoration of the foot and in this particular case, required two surgical interventions. As we move back into the midtarsus, we get a peri-navicular. This is an interesting deformity because it involves AVN with collapse of the navicular. This produces an adducted foot. Typically, the opposite of what you expect to see with a Charcot deformity. And you can see on the lateral view there the fragmentation of the navicular in this particular case. What you need to decide here is that in spite of the adduction, is it a plantigrade foot. And if, in fact, it is, the only reconstruction you need to do is fusing the talo cuneiform complex. Of course, bone graft is necessary in order to do that. These people develop an ulcer laterally. And this ulcer unlike the navicular cuneiform also occurs very quickly. But most of these are salvageable provided you can get in there prior to this type of inversion or supination deformity of the foot occurring. Once this occurs, you put the ankle at risk. And the only thing more difficult than doing a salvage of a Charcot foot is the salvage of the Charcot ankle and foot simultaneously. So you want to try to prevent this whenever possible. The ulcer pattern in this type of foot starts laterally and just keeps getting larger. Without doubt, the major involvement of this is not only the cuboid but also the proximal basis of the fourth and fifth met. And if, in fact, you develop an osteomyelitis in that area, then you are removing much of the lateral stability within this foot. And a typical presentation is something like this. You can also get this iatrogenically. And by that I mean, in this particular patient, this patient had numerous attempts at a local amputation. And one of the results of that was to render the peroneus brevis nonfunctional so the patient develops this type of inverted adducted foot type leading to this ulcer pattern. And this patient goes on to develop, fortunately, a very superficial localized osteomyelitis which was treated with debridement, antibiotic beads. And then at a second visit, a fusion of that particular area which not only corrected the adduction but also the rocker bottom that had occurred.

    [00:25:05]

    And it then went on to stabilization with a frame followed by skin grafting and not a very aesthetic result but a very functional result in this particular patient. Let me move on here. The midtarsal classification brings a number of different problems to bear here. First of all, when you have involvement of the talar head and the talus due to a longstanding ulcer, it develops an osteomyelitis, then you have a situation where the ankle can be involved in no time, especially if the talus collapses. This basically require triple arthrodesis to reconstruct. You can notice that the subtalar joint in this lateral view is significantly involved. So even stabilizing the primary end joint area does not really produce a very stable appendage for this patient and you, therefore, need to stabilize the hindfoot. This usually involve stabilizing the calcaneal cuboid joint. This has the most variable ulcer pattern and it all depends on which side of the foot collapses first and whether or not you get an abduction deformity because I've seen these pure sagittal plane deformities without abduction. Those are not necessarily easier to correct because the primary correction is in the sagittal plane. You need to neutralize the rocker bottom deformity. But this is a kind of presentation that you will see in a patient like this with complete dislocation of the midtarsal joint. When you look at this, the boney architecture is actually quite healthy. What is, in fact, the pathology is the alignment and this patient will usually present this way. And this is where, over the years, I have always tried to reposition this foot underneath the leg. Can that be done, yes. Is it worth the time that it takes to do that for the patient, I'm not sure because you have multiple joint involvement, multiple plantar deformities and consequently, we have relegated these patients to doing a tylectomy with tubial calcaneal fusion and any one of a number of different strategies in order to correct this particular foot. We've used intramedullary nails. The only thing I would caution you is that, when you are using an intramedullary nail for a tibial calcaneal fusion, it needs to be a straight nail. So the reason is that in the normal foot, the calcaneus is lateral to the tibia. When you remove the talus, you need to medially displace the calcaneus and posteriorly displace it. And it's very difficult, if not impossible, to get good placement of a valgus nail in that kind of situation. So you have a lot of nails at your disposal and it's not unusual for me to use either a humeral nail or a distal femoral nail which are straight. I think the most important part about an intramedullary nail is its length, not it's diameter and consequently, it is not unusual for us to use between 2 and 300-millimeter nails on a routine basis as opposed to the 150-millimeter nail, which I think is a two-stage procedure. You put the nail in and then you treat the complication. So the length of the nail is important. It must go past the isthmus of the tibia in order to stabilize. It is also not unusual for us to protect these nails especially in Charcot with a neutralization frame. I think it's important to realize that you're putting nail and diseased bone. And consequently, we don't hesitate to use neutralization frame in order to project that until we see healing start to occur.

    [00:30:00]

    We've also used Pin-To-Bar type constructs, creating a footplate with the Pin-To-Bar and then using a delta construct on the leg in order to stabilize that on a temporary basis. Just a couple of last words, do we do tendo Achilles lengthenings, no. What I like to do or either gastroc recessions or a Baumann procedure which is releasing the fascia. That's usually done midleg. And the only reason I say that is that I'd like to control the length that I'm attaining. Consequently, I do not think that I am trying to achieve ten degrees of dorsiflexion. I'm trying to get the foot above zero. And if that's one degree, that's fine with me. If the foot is plantigrade, I'm happy. When do we make that decision, we make it during the surgical procedure to see how much we can do. In certain cases, gradual correction is necessary. For instance, the posterior muscle group lengthening is done here. The foot is stressed into dorsiflexion on C-arm and we noticed that everything is dorsiflexing but the ankle. So the dorsiflexion that this patient is getting is at the level of the Charcot involvement. Gradual correction, therefore, is indicated and in order to do this, the only thing available to us right now is the TAYLOR SPATIAL FRAME, very powerful tool. If I'm just doing a midfoot correction, I'll use what's called a butt joint which looks something like this and you see that it's connected by six struts. And what will happen is that changing the length of this six struts will reposition the forefoot to the rearfoot and then I will do internal fixation. In the beginning, I used to leave this frame on the entire time until consolidation was achieved. However, that could involve three, four months of frame. My patients didn't like that too much. So what I do now when I use this is I use the frame to reposition the foot. And then as soon as it's repositioned, we go back for a second involvement and do internal fixation. This means that the frame is on three to four weeks as opposed to three to four months and I get similar results. The last thing I will show you is when I'm trying to correct multiple planes, I'll use what's called a miter frame. A miter frame has a 45-degree angle, two-thirds ring around the hindfoot and six struts between the hindfoot and forefoot, six struts between the leg and the hindfoot so that the frame looks like this. Most patients can't handle this. So visiting nurses will change the strut lengths for us and this allows me to not only correct the forefoot to rearfoot relationship, but also with the six proximal struts, correct varus valgus and equinus simultaneously and then the frame is removed and internal fixation is applied. I see the Grim Reaper at my side ready to come up, so I will end right there. Thanks for your attention.