More Thoughts on Options When There is No Talus
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Transcript
Jennifer Spector, DPM: Welcome back everybody to Podiatry Today podcast where we bring you the latest in foot and ankle medicine and surgery from leaders in the field. I'm Dr. Jennifer Spector, the assistant editorial director for Podiatry Today and we're bringing back yet again Dr. John Visser, who began speaking to us last episode about some options when there is no talus to work with. These are very unique and very serious situations we may find ourselves in clinically and he's sharing a lot on the etiology and some approaches to this. So let's pick up where we left off last episode and hear what else Dr. Visser has to say on the topic.
H. John Visser, DPM, FACFAS: At these particular points, what happens, for example, in the patient that developed a systemic disease type of issue. Those particular patients will not have oftentimes a significant deformity but they normally will ally will and you start to get into fusion and again, the amount of bone loss determines how you do the fusion.
For example, in this first case, it may just be the dome of the talus has flattened out given an osteoarthritis. But if you take a look where avascular changes stop, it's basically superior to the neck of the talus. This is where we can use total ankle arthroplasty because the remaining body of the talus is still well intact, and we can treat that arthritis. If it gets beyond that, then we cannot depend on the talus at all for any stability to the prosthesis at that particular point. And so in this case, that's the only indication for a total joint in a neuropathic patient. And then some people may not even feel comfortable with that.
Early on, the very first things that we would utilize is femoral head allografts, especially in the diabetic patients where we have significant loss of the talus and significant instability, whether it's in a valgus or varus position. In this particular instance, oftentimes the fibula will rub inside the brace that's being utilized creating an ulceration that can become osteomyelitic. These cases require a transfibular approach to involve the ankle and you would use a fresh femoral head. We use acetabular reamers to create basically a concave/convex ball and we then go ahead and we use biologics to inject the femoral head to try to incite that we will get creeping substitution to occur. This is what we used to use universally in these cases. The stability and the fixation was either an intramedullary rod or it was some form of external plate fixation. Usually 1 or 2 screws run from the calcaneal portion through the graft into the tibia to hold the graft in position and then stabilization with a long locking plate along the lateral side.
The other option you can do would be to be consider a tibial calcaneal arthrodesis or even a Blair arthrodesis. The Blair, as you may remember, is an older procedure, but sometimes still used, where you take the tibia and create a rectangular sliding slot and lock it into the neck of the talus. Remember, a lot of these avascular changes that lead to significant body loss still allow the neck to be intact because the blood supply to the neck is not highly involved even in these Charcot situations. And then basically that filler area, we have new options there. We can actually use these 3D types of titanium spheres that can be placed into this area. And these are trying and work, I think, much better than the femoral head allografts.
The problem with the femoral head allografts is we have a high incidence of non-union because the creeping substitution usually only goes part way and doesn't get the center. And what you begin to notice when you have failure is if it's an IM nail, you begin to see loosening of the nail, nail needs to retrograde movement back out and that's going to require revision. Same thing, if you're using plating situations, you're going to get loosening of the heart. We're going to notice the loosening. It could go valgus. If it goes valgus and it's relatively still stable, you can probably get away with that. The patient will heal enough that they have enough stability with an AFO to function unless they have severe amounts of valgus and I mean you can get away somewhat 4 to 6 degree heal valgus.
Varus can't be tolerated in any particular way. If it tilts into varus, you got a revision on your hands in that particular situation, but the 3D spheres are something that are very nice and then they can be loaded with bone graft. The problem with the newer things that are coming out, and we'll go into them, are obviously cost issues that we have to deal here in this situation.
Dr. Spector: What about a tibiocalcaneal fusion? What options might be available there?
Dr. Visser: With a tibiocalcaneal fusion, which obviously the biggest problem is leg length discrepancy, so-called anisomelia, if you are experienced in a situation where you can use a ring fixator and do callus distraction up just below the tibial tuberosity, what we call traction histiogenesis, you are able to potentially dock that tibia to the calcaneus and regain its length but this would require you to be able to be very, very well trained in utilization first of ring fixators and secondly basically where you've been trained in distraction histiogenesis.
Dr. Spector: Can you share a little bit with us about tricortical titanium struts?
Dr. Visser: In these cases the whole body is not lost in some of these cases. Part of it is lost, but actually through bioengineering, you're able to create this 3D truss to fill the area that's diseased and apply it to an area where the bone is still nice and intact, has good blood supply, and basically is strong. And this works very nicely to augment what's left of the talus in that situation. And I find it, it's less expensive. When you can use it again, you can backfill it with either allograft or autograft in that particular situation.
You also have these cones that replace the entire talus with have built-in intramedullary rods that will allow a rod to go through that. And it actually replaces the talus. Now, with these, you usually have a full talar body loss. And in these cases, you usually have to use a ring fixator to get the distraction you need, usually over a slower period of time to get it out to length to the opposite side. That is what you're comparing it to. Once you're able to get to that, then you can use, again, this rectangular form. Some are rectangular, some are rhomboid, and these trusses with areas where you allow an intramedullary nail to go through can be utilized.
Dr. Spector: Is there anything else that you think surgeons should keep in mind?
Dr. Visser: Well, these are the big things that we utilize and now we have newer stuff. But now also that's been on the horizon has been utilized, obviously, is the total talus. The total talus has been now utilized probably over the past 5 years, maybe. Again, the problem here would be cost. Now, a good instance for this is basically where you have a talus that becomes damaged, usually from some systemic process. There's a loss of continuity and flattening, but the space is well maintained. Okay. And in that case, it's a very good indication for avascular necrotic changes. Because basically, the space is maintained. The basic length between the tibia and the calcaneus is usually maintained. Usually if you need further distraction, you can use a Hintermann there to help assist in that area.
The other thing in these cases is you have to look at the tibia itself. What does the tibia look like? Is it arthritic? Is there damage to the tibia that's been going on? In that case, you may want to consider then a usually an in bone stem into the tibia, which articulates with the talus and then it will obviously give more free range of motion and will prevent usually the tibia from being broken down in those particular situations. So a lot of people will use both because they're concerned about the tibia with the wafering surfaces in this area. And the talus is cobalt chromium and molybdenum in this situation. So it's not, it's a little bit hard compared to obviously these truss systems, but the truss systems are big bone fillers, but the talus actually anatomically replaces the talus with the same geometry of the original talus.
So I think that's the most new thing that's out there to treat the loss of the talus where you have significant instability, significant loss. Again, you can use these in situations where you do have significant loss of space, but you want to try to avoid neuropathics. The neuropathics will not work here. They will not tolerate that particular form of metal and weight-bearing force. So these are reserved for cases usually post-traumatic or from a systemic cause.
Dr. Spector: Are there any final thoughts that you would like to leave the audience with today?
Dr. Visser: My final thoughts are this. Recognize that in the case of a Charcot osteoarthoropathy of the ankle. Now the other cases give you a little slack. You're able to usually maintain the talus. It's shaped most of the time and you're able then to consider some of the things that you may want to do in this situation. The Charcot is a bad life-threatening and limb-threatening issue. You can't really sit around and put these people in CROW boots and let them ambulate. They will basically break down, the talus will break down, the tibia and fibula will become distracted, there is no syndesmotic stability, ulceration is going to occur, it's going to either be over the medial malleolus or it's going to be over the lateral valence.
Once it does, what do we know? The skin integrity is very, very thin there. You have your skin, you have your fascia, you have your subcutaneous tissue. Once it gets through subcutaneous tissue, it's on the periosteum and it's right into bone. An osteomyelitis occurs at a very, very high rate there, okay, and it will contribute to bone loss, not to mention then the patient's going to be on long extended periods of intravenous and oral antibiotics in these situations.
You need to be aggressive with these people there. And in some instances in these cases, you go ahead and you do your resections and you stabilize the tibia and the calcaneus or the tibia to what's left of the talus and the calcaneus, with Steinmann pins ran from the heel into the tibia. Once you get everything heeled and under control, you then can go ahead and consider what type of revision you will need. So I think these are really something that you don't wanna mess around with. These are the things that can get you into legal trouble because they know what the options are here. They know what causes this problem. They know how severe it is and how you must really jump on these cases very, very quickly. They're almost like a chronic regional pain syndrome.
And as we know, Charcot really is. It loses its stability. There's no autonomic function present. We lose anatomic stability. And if you were to bone scan a patient early in the case as stage zero with CRPS and Charcot, they would look the same. Absolutely look the same. That's something that a lot of people are not aware of. And oftentimes early in the case where everything looks normal, yet the patient's got swelling or erythema, X-rays are negative. a bone scan can be very helpful here, obviously MRI, and early diagnosis can be made, which is very important. We know, unfortunately, primary care is very ignorant in this particular area, as are a lot of other physicians who are not recognized this problem very well.
The radiologists too, you know, they jump on the bandwagon, because they tell you, well, a Charcot process in osteomyelitis, it looks pretty much the same. And they call it osteo universally when you have multiple bones involved. Well, how can they have multiple bones involved with osteomyelitis? That's a Charcot issue straight on. If you have an isolated area over a pressure ulceration, sure you're dealing with osteomyelitis, but you need to be really clear with the radiologist what's happening, otherwise you're gonna call it osteo. And even though the patient is a Charcot patient, it's almost gonna be relegated to the fact that you're going to have to use antibiotics. Just have to tell the radiologist. I have no open areas here. You don't get hematogenous spread into a Charcot joint. It just never happens. So that would be a thing I would point out.
Dr. Spector: Thank you so much, Dr. Visser, for sharing all of your insights on these really interesting topics over the last several episodes of Podiatry Today podcast. We hope that you'll tune into his three previous episodes, getting into some of the details on options when there is no talus, and also a cable approach to perineal tendon dysfunction. You can tune in on podiatrytoday.com, SoundCloud, Apple Podcasts, Spotify, or on your favorite podcast platforms.
