Options to Consider When There is No Talus
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Transcript
Jennifer Spector, DPM: Welcome back to Podiatry Today podcast where we bring you the latest in foot and ankle medicine and surgery from leaders in the field Today we are so happy to have Dr. John Visser back with us again this time to talk about options when there is no talus. He's a Diplomate of the American Board of Foot and Ankle Surgery as well as that of the American Board of Podiatric Medicine, and he's a Fellow of the American College of Foot and Ankle Surgeons. He's A Past President of the St. Louis Podiatric Medical Society and the Missouri Podiatric Medical Association, and has also served on the Missouri State Board of Podiatric Medicine where he's been appointed by three governors. He's very involved in podiatric education and he's a past Director of Residency Training and Foot and Ankle Surgery at Mineral Area Regional Medical Center and later at SSM DePaul Health Center in Bridgeston, Missouri. Welcome back, Dr. Visser. We're so glad to have you and thanks for being with us today.
H. John Visser, DPM, FACFAS: Thank you very much. Really look forward to it.
Dr. Spector: So this is a really interesting and unique situation when there is no talus to work with. What situations might arise that lead us to this clinical question of what to do, or rather, what has to occur for a patient's talus to be in jeopardy?
Dr. Visser: Well, it can be in various groups, and that's kind of the way I like to think about it. The first would be actually medical causes. The biggest, obviously, would be corticosteroids. You also have patients who are alcoholic, tend to be in a higher risk group, patients with thyroid disease, also your autoimmune disease, rheumatoid arthritis, systemic lupus erythematosis, and there are other types of disease states that are much less common, but that would be the biggest group where the talus could be at risk. The difficulty is, is that obviously you and have patients that fall into this category and never really have the problem, and then you'll get cases where they actually do.
Here basically it begins with loss of blood supply to the talus—corticosteroids. What the belief is is that in the cancellous bone, obviously there's an amount of fatty tissue there in that area. And what happens with utilization of corticosteroids, you get an increase in the amount of fatty distribution. This puts pressure on the meanest sinusoids within the talus and leads to enough pressure to create basically a loss of backflow of the artery flow to the talus. And this is what can basically happen in this situation. So we're dealing with basically an interosseous compartment syndrome in that situation.
Alcoholism, I think the big issue there is the toxicity that actually damages these small arterioles and basically leads to decreased blood flow and avascular changes. It does take a longer period for the talus to be collapsed, the problem is making the diagnosis. In these cases, patients will kind of have non-specific changes and they will have low-grade swelling. But you take an x-ray and early on, you may not notice any kind of damage to the talus at all.
But with the advent of MRI, you can make a very early diagnosis and not have to depend like we used to have to, which was on the radiographs, looking for that increased density usually within the dome of the talus. So it's slower. And so if you get it recognized and the disease state can't be treated, but it's not going to change what's what's gonna go on here. What happens is that obviously the dome becomes very vulnerable because of the fact that the cancellous bone content is weakened and with continued weight bearing, it can lead to collapse of the dome and then this will lead to significant osteoarthritic changes.
The treatment of this is obviously early on was non-weight-bearing. The only thing that was really offered for this is to get this patient completely non-weight-bearing. The reason being weight-bearing would lead to further damage and compression of the soft dome of the talus. And then this would lead to deformity. The severity of the deformity and the life-threatening portion of it is not as much in this situation because you have options here.
More recently, we have the options of basically doing core decompression like they do with it in the femoral head, where avascular necrosis is very well known here, where you take trephines and you basically decompress this area underneath the dome. And in some instances, no bone grafting is needed. It's just basically removing these pressures, especially in cortical steroids. You want to decrease the intercancellous pressure so that the dome is preserved. But in some instances where it's more arterial, like a rheumatoid, you may want to use some grafting there to support that talar head during that particular time.
Again, weight-bearing is going to be non-weight-bearing there. Nowadays, we do have the knee walkers that makes it much easier for patients to stay off their foot. Not like before the advent of these where basically, the patients had to use crutches in this particular instance. Also, it's always ask how long is it gonna take? This is a tough, tough thing. If any type of non-surgical treatment of this may take well up to a year. So in some instances where the patients need to be more mobile, you do have the patellar weight-bearing braces. That is a particular option.
Dr. Spector: So you spoke a little bit about the historic approaches to this concern and some contemporary ones, do you feel like there are even next steps that we're going to be taking in the future for this concern?
Dr. Visser: Yes, definitely so. I may also want to just expand a little bit from the initial discussion about the other things that can lead to damage of the talus. Of course, the big one would be fractures to the talus, talar neck and body fractures with your Hawkins classification. If you have a 1, which some people think there are no 1s and need fixation, usually from 2 incisions, 1 medial and lateral. But when you get into the stage 2, which is basically where the subtalar joint becomes subluxed, then 2 areas of blood supply are cut off. With a neck, it's 1 involved. Then you have the stage 3, where you have ankle dislocation in that situation. And then you have the fourth, which was described by Canale and Kelly, which basically led to the talus being dislocated from the talonovicular joint. Now those, the 3 and 4, are going to be for sure avascular necrosis changes.
And the problem here now is we're dealing with significant fracture dislocations that require surgical intervention. With the surgical intervention, again, you have to basically get this patient non-weight-bearing, monitor them. You use that Hawkins sign usually at 6 to 9 weeks in the dome of the talus laterally with some lucency. That would indicate that probably the blood supply of the talus is intact and you monitor them from there. So again, you will have usually with the open reduction internal fixation, the talus in good position. But again, you're going to be dealing with avascular changes, which will lead to eventual collapse.
You’ll also be concerned about malunion here with the talus, especially in the 1s and 2s, and all of them actually, because what happens is, you have to get the medial side lined up properly. Most of the time when you do the open reduction, you're going to go laterally because that's usually more of a linear fraction, doesn't have a lot of combination. You get that lined up, you can put a screw across it or a plate, and then you look at the comminuted side and basically there's gaps there. You fill it with bone graft and use plates in that situation or you can use a screw in a strut fashion, not a compression fashion there to basically maintain the alignment.
The problem with malunions is you will notice the symptoms much later. A year down the path the patient starts noticing chronic pain because there is some subtalar arthritis but the big thing is the subtalar joint is accommodating going into a varus position. And once the talus moves in that position, the heel goes into a varus position at that point and the patient's walking on the outside of the foot. The talus at the neck area is also involved so it can affect the midtarsal joint and the midtarsal joint will go into a varus position too. Remember, a subtalar joint and the oblique midtarsal joint always move together. So if the subtalar joint is going to supinate, so will the oblique midtarsal joint.
But the talonavicular joint always goes different. That's the longitudinal midtarsal joint axis. And that will go into basically, in that case, a tilted almost valgus position, where the TA becomes a deforming force at that point. Okay, so it's a tough problem once it goes on and is not really recognized. It's really treated by a tailor neck wedge osteotomy, which can be corrective to bring the subtalar joint back into its corrected neutral position. but if there's long-standing issues in arthritis, it may require a subtalar fusion or even a triple arthrodesis. That's the trauma to the talus that can happen to it.
Then the third big one, which of course a lot of the podiatric surgeons have to encounter, and these are very serious limb and life-threatening, and this is obviously the case of Charcot osteoarthropathy involving the talus here. Because not only does the talus become involved, fractured, unstable, the whole ankle joint in the foot becomes unstable, the alignment of the foot to the ground is abnormal. It can be in a varus situation, which is very dangerous, very difficult to deal with from a of standpoint. Putting them in a CROW walker—once the deformity occurs, it's not going to be that helpful. It does require, if you can catch it early on, an open reduction internal fixation with the utilization of extension of your fixation well beyond the normal limits we usually use.
In other words, the normal way we deal with an ankle fracture, let's say a bimolelar, fix the fibula, the medial malleolus. Here we use on the lateral side, usually a 5 or 6-hole plate. And then we use a compression screw on the medial side. We use 2 compression screws. In this particular case, we have to really wedge the talus together. Those incisora areas between the medial mallelolus and the medial body of the talus and the lateral body of the talus and the fibula have to be really adequately compressed because the soft tissue structures like the anterior and tibiofibular ligament and the remaining soft tissue structures of the syndesmosis are damaged. The syndesmosis has to be stabilized. That talus has got to be pushed and locked into position.
You're going to then have to have multiple transcentismotic screws, these are 4 cortices. You use mutimoleolar screws that purchase the opposite lateral cortex, and you extend your fibular fixation well beyond the bounds of basically normal bony mineralization. These are all basically the criteria that are now used in the patients who have this particular situation.
And it's very important to recognize that there is true neuropathy, and that's how it has to be addressed. Unfortunately, oftentimes they get missed, and the next thing you know, you see loss of fixation in placement. In those cases, you may attempt to go back and do the things we talked about. But oftentimes, in that case, you may have to consider a talocalcaneal tibial fusion, basically a subtalar ankle fusion, basically with preparation of the joints. And in some instances now, people are not prepping the joints and running an intermedullary rod to stabilize the tibia to the talus and a talus to the subtalar joint and obviously ranking that talus and the syndesmosis in together so that you have stability.
Dr. Spector: You've really given us a lot to think about on this topic today, Dr. Visser. And we'd like to thank you for joining us again on Podiatry Today podcast. Be sure to check out this episode and Dr. Visser's previous episodes with us on podiatrytoday.com, SoundCloud, Apple Podcasts, Spotify, or on your favorite podcast platforms.
