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FAI June 2024 Podcast: Revision Total Ankle Arthroplasty Using the INBONE II System
00:27:48
The utilization of total ankle arthroplasty (TAA) for managing severe ankle osteoarthritis has become increasingly common, leading to a higher occurrence of revision TAA procedures because of failure of primary TAA. This study aims to examine the...
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- [00:00]
A
Foreign this is Charlie Saltzman, editor of Foot and Ankle International. Today I have the distinct honor of talking with Dr. Jim Diorio who is the senior author of June's lead paper in Foot and Ankle International entitled Revision Total Ankle arthroplasty using the in bone 2 system. I selected this study to highlight Dr. Diorio's group's large experience taking care of the challenging problem of revising failed total ankle replacements. Dr. Jim Diorio from Duke University and well known to all of us in the field of foot and ankle. I want to welcome you to the program today, Jen, and ask you if you could give a brief summary of your paper and its major findings.
- [00:55]
B
Thanks. It's a pleasure to be here. So we looked at a group of patients on whom we had done revision ankle replacement. We do a lot of ankle replacements here, a lot of primaries. I've done about 1600 total ankles in my life. Consequently we get to do more revisions than most people. They're not only our patients, but they're patients who are referred from all over the country. Virtually the key ingredients for a need for a revision total ankle is of course loosening was the number one cause, cyst formation, which may be in part due to the polyethylene. Maybe that'll be reduced now with the new vitamin E induced polyethylene impingement. Then some patients required a subtalar fusion for symptomatic arthritis. And of course then there were a few infections as well. So those infections were not included in the study. They were removed and then they were treated with a two time operation. One to remove the ankle and implant an antibiotic spacer and then a second to come back and do the ankle replacement itself. So our results were reasonably good. They were about 93% successful in preserving the ankle. Now it was a short follow up and it was at three years. And we fudged a little bit that because 14 of the 60 patients were actually followed for less than two years. But we called them up, made sure there was nothing wrong and it's highly likely that almost all of those survived the two year mark. But we were allowed to get this into print because it's the largest article that exists on revision total ankles. And by allowing us that 14 patients it increased our number. So we'll of course follow these up in the future and see how they're doing. But I think they're going to do reasonably well. In Hinterman's article he had an 82% success rate and that was for six years, minimum follow up of six years. So we may. We may lose 10% in there, but hopefully not because of the prosthesis we're using now. This article specifically addresses the inbound, and this is the ingenious work of Mark Riley, who invented the inbound total ankle. And together with an engineer named Mulder, they developed a truly fabulous idea. It was just at the time that the ankle came out, and they presented it at the Foot and Ankle Society summer meeting that I had run out of star ankles to do on the US study. So I had done a lot of star ankles and I had a lot of people lined up for them, but suddenly there were no more stars available to do. And so I was eager to get my hands on an ankle. I wasn't keen on doing the agility. And so when I saw this ankle, I immediately liked it. I flew out to Denver, did a saw bones, then I did two cadavers, and then I brought the team back with me, and I did three on that following Monday. So they were aghast because they said, oh, you can't do that. Dr. Reilly only does one. I said, well, if this ankle is going to work, it's got to be able to do multiple ankles in a day. And I had a really good fellow with me at that time. And so, as you know, they do most of the work anyway. And so we were able to do all three ankles and go out for a spectacular dinner. So that was my start of doing the inbound ankles. I think altogether I may have done as many as 600. So using it as a revision prosthesis was very comfortable for me. And then thanks to the ingenuity of the group of people at Ortho Carolina and Steve Hadded, they created what I think is a fabulous revision ankle. It's called the inbound. And then it then adds the Adelaide title onto it, Envision. And the envision is unique because you have multiple thickness of a base for the prosthesis that goes into the tibia, and that allowed you to make up significant loss of bone. And similarly, on the talus, the talus was created so that it would go in and have an extended length. And so I particularly liked it if I had a Tata navicular arthrodesis or was doing a tail navicular arthrodesis, and I could bring the. The distal end of the Taylor component all the way out past the tail navicular joint to the navicular cuneiform joint. So I think it was a splendid prosthesis. It was designed for revision. One of the Few ankles that that's been the case. So in our study, we did about half in bones standard and then half invisions. We believe so much that the fixation is in the tibia is absolutely vital, not only to a revision ankle, but also a primary ankle. So the ankle, the ankle that we've worked on for the past few years, called the Vantage, we are now coming out this summer with an extended stem on the tibial component because it's my belief that many of these ankles have minimal fixation on the tibia and they can't help but get loose or develop osteolysis underneath them and then hence need a revision. So we did reasonably well with our ankles and we had a moderate number of complications. So 36% of the patients, or rather we had 36% complications, 93% of the ankles were doing well and didn't require any further surgery. But we did have a relatively high or moderate complication rate of 36%. And these included lots of different things. Fractures after the surgery, failure of the prosthesis, a few infections, nerve impingement. But one that was the most was actually continued pain. Despite our best efforts on putting the new ankle in and having it look reasonably well, we still had some patients with pain. I'm not sure what that pain was secondary to, but I do think that it's a combination of weak bone and movement of the prosthesis and not even so much loosening as it is stress of the metal on top of the bone that causes pain and patients. And I think that's something that's hard to prove, but I think it was definitely there.
- [08:06]
A
Thank you for that great overview. Historical overview, in summary, only you could give it. I have a few technical questions for our, for our listeners. I saw that about 2/3 of the cases had medial mal fixation and 5th had deltoid releases. So as a true expert in this field, can you describe your thinking about when do you do those types of procedures and impart any technical pearls to our listeners to make this work well in their hands?
- [08:41]
B
Sure. Let's start with the deltoid release. Oh, I don't know, Maybe it was 2003 where Bonin B o n I n in France who developed the salto telaris ankle, showed me the deltoid release and he said, jim, with this you won't have to do nearly as many ligament reconstructions. And he was right. I came home and started doing it. And even though I didn't invent it, I certainly did popularize it. And, and Charlie, you Know, I can tell you I've done hundreds of them and I've never had one fail. I mean, that's hard to say, but if you completely strip the media malleolus of the deltoid, and I mean from front to back, I mean, Roger, when we were doing the star, would. Would talk about a partial deltoid release. And I could never figure out how to do that. I didn't know. I mean, you know, it was either all or none. And so when Bonin told me this, I said, oh, that's great. And so now that became a key to doing all our varus ankles. It allowed us to establish equal stability on the medial lateral sides. And I just don't remember a failure of a deltoid release. The other procedure that you brought up is the medial fixation. Now, you'll remember that when we were doing the STAR FDA study, that there were some people, including myself, who had a number of medium fractures. And were we twisting too hard or trying to push the bone past its capacity? Well, yes, because many of these people were osteoporotic. Many of them, far more than we know, were vitamin D deficient. So they had crummy bone. And so it became a very low threshold for me to put in a fully threaded. I started with partially threaded, but I kept going with cannulated screws. And then I found a tapered fully threaded screw to put in over a guide pin on the medium. Illegal. And it takes about three minutes. You only need an AP view because your hand, when putting in the guide pin, should be parallel to the floor. So it wasn't necessary to take a lateral view when you were putting in the screw. And I Learned about a 40 millimeter screw is adequate. I always did that when I revised ankle fusion takedowns, and I always did it when they were as a valgus ankle with an unstressed media malleolus and softer bone. But it became so common that I started doing it in almost everybody. Because when you're doing a revision total ankle, you're moving the cut on the tibia approximately and you're leaving the lever arm on the proximal aspect of the tibia medial junction. That's longer and it's more stress on that side. And for those of you who have fixed, and if you're doing any total ankles, I'm sure you have have fixed a medium alar fracture in the middle of the surgery. It takes time. Most of the time they work, but I tried not to put a plate on. I would just do the same technique with one screw and sometimes two. So it was much easier to put that screw in. It was faster, I felt safer. I thought I could provide the patient with a better preoperative, sorry, post operative weight bearing result and they could weight bear almost immediately on these ankles. So it became a very, very common thing to do. And since I did so many of them, I put in probably more of these medium Alex screws than anybody else.
- [12:36]
A
Let me ask you one more technical question. It's one that I'm sort of bringing up because it's, it indicates where we're going and maybe you can shine some light on this. I would assume that for some of these ankles you use the in bone external frame to get your alignment or perhaps you use PSA to guide you. So I'd like to hear your thoughts on the pros and cons of both. When is it appropriate in a revision setting to use a psa? When would it maybe not feel appropriate to you? And where do you see PSA fitting into the paradigm?
- [13:21]
B
Thanks for that question. I started using PSA maybe about two or three years ago. I was a little bit late coming on board because I was so comfortable with the ankle that I was doing and the cuts I was making and the results I was getting. But I clearly realized that using PSA would give me a better handle on things and you could always abandon PSA and go back to a standard technique. However, for most of these ankles that we did in the study, I did not use psa. The inbound is itself a guide and it gave me a very good guide. And so I learned to take the lateral border of the tibia just above the prosthesis and draw a perpendicular line to the talus. And so that gave me very, very accurate alignment. So for the vast majority of these, if not all of the revisions that I did using the inbone, I used the external alignment guide. Now, initially let me go back to Garrett Malden and Mark Riley. Their plan when I started doing the inbone was to recommend that you put the ankle in the holder and then you open up the ankle. And I immediately realized, I said, I'm not going to work over this. That's going to be too difficult. So I started opening up the ankles and doing Achilles releases right away. And if I couldn't get the ankle up to 90 degrees and it wasn't possible at that time to use the inbone external system. So most of these were done with the external system. I have no problem with people getting a CT scan and getting PSA created, but I. But I like the inbone a lot. I won't say that they were 100% perfect, but 90% were in a very, very good range of 2 to 3 degrees varus or valgus, and similarly for flexion and extension of the tibial component. So most of them were done using the external guide.
- [15:34]
A
The inbone is positioned well as a revision implant. What is the plan for revising an inbone when it fails? Is it straightforward to you?
- [15:45]
B
That's a good question. And I have had to revise some in bones. I was always very cognizant of the amount of bone I was removing. So I used to do total hips and total knees. And when I did total hips, oh, I was really loath to take out any bone and instead I always left with more bone in than when I came in. Well, the same is true of the ankles. So I would never take out any good bone and would only take out bone that was in the way of putting in the, the prosthesis. So using bone graft and other things, we managed to supplement the inbound and the stability that we were getting with the prosthesis.
- [16:31]
A
So if I pull out an inbone that is loose and I put a new one in, you think I just go ahead and bone graft and I'll be all right, or should I take any other tricks?
- [16:45]
B
Yeah, there are, there is one big trick that actually Mark Easley mentioned to me. So my, my favorite tool when I'm doing revisions, particularly the inbound, is the small TPS reciprocal saw. So most people know what that is. That's about a 1 inch saw by a 1/4 inch blade. And so I would take out the base plate of the existing end bone and then I would approach the stem. Now, getting out the stem is not easy. And so I would take that small reciprocal saw and then I would pass it vertically and I could get it up fairly high. I would make a small window. It appalled me when some people made windows that were as tall as the prosthesis. So that's not the thing to do because that does not preserve the boom. So using the small reciprocal saw, you could get that in vertically and you can get that almost around to the full back of the inbone prosthesis. Now, the in bone doesn't fully ingrow. If it did, I don't think you'd be able to take it out. But it does spot weld. So it spot welds and you have to find the spot welds and you can find them with that small reciprocal saw. Okay. So now we. We fiddle with this, and we get that small reciprocal saw up there higher than we can get a. An osteotome or anything else. And then once we've done the maximum we can do, now we have to get the prosthesis out. So there are impactors, there are straight tools, and they're heavy. There's a particular design that I like called V. Mueller. And it would come in a square, a large rectangle around. They're about $5,000. So they were really finely machined. So then I would hit the prosthesis with the edge of a square nose impactor. I would hit it hard, and then Mark Easley said, you know, he said, why don't you just put the wrench on? And I went, oh, my gosh, of course. That's a brilliant idea. So then, from then on, whenever I had to take an in bone out, I take out the base plate, and then I would clean up at the. The distal end of the prosthesis, and then I would clean it up just enough to get the last wrench on that fit the component that I was trying to get out, and I would put the wrench on. Now, with the wrench on, I would take that impactor and I would hit it distally, and I would use a pretty big hammer. I'd start tapping lightly, and some of them just came flying out because, again, the in bone wasn't fully ingrown. It was only spot welded. And so relieving those with the reciprocating saw, that was. That works perfectly fine without a lot of pressure and about 50% for the other 50%, I would. I would either coach myself or the fellow. I say, hit that. No, no, hit that. No, no, hit that. And so with that, there was very little bone left ingrown on the inbound. And I was able to get the prosthesis out through a very small window, maybe about 15 millimeters, whereas the total height of the in bone would be 40 or 50 millimeters. So do not. Do not take out a full window to take out the end bone. Use the reciprocating saw, get it loosened up, and then use that technique of putting the wrench on and then hitting the wrench distally, and they all came out.
- [20:28]
A
That's. That's brilliant. Thank you. I can just follow with a few quick questions at the end here that I think is really important. What patients are not candidates for revision? Total ankle arthroplasty, in your opinion?
- [20:44]
B
Right. So the obvious one is when you're suspicious for infection or you know, there's an infection, then I, I do not believe in single stage revision. Rather, we took the prosthesis out routinely, got deep cultures, and then put in an antibiotic spacer. And that was very successful. So I would not do a standard revision for an infected ankle. The other case where you have to be careful is looking for avnot. Now, when we started doing the inbound, and some people sent me their cases when they started doing the inbound, we got AVN of the talus. That hole coming through the subtalar joint isn't so much an arthritic producer as it is a devascularizing technique for the talus. Now, it doesn't happen often, and in some people it virtually never happens, but I had it happen to me. And then I would see people go back and try to do a subtalar arthrodesis to salvage the, the ankle, but that's not going to work. And so if you have avn, we were stuck. And then when I say stuck, I meant that I didn't think doing a revision was appropriate. Now, if there's just a small amount of avn, then I really employed that envision, which covered more of the anterior superior length of the talus than any other prosthesis. And so that was a good prosthesis to use if it got to be significant avn, we got smart and followed the, the advice of some of our colleagues overseas and started doing total tailline. And so when you do a total talus in combination with a total ankle, that's called a combined total ankle, as most people know. And so those have worked very well. The literature now supports doing that, and the success rate is in some cases above 95%. So you don't want to do a standard Taylor prosthesis. If you have AV into the talus, then there are some strange cases where you have significant loss of bone. But even in those cases, I didn't feel like it was absolutely necessary to get a 100% flat cut on the distal tibia. If I had a 75% cut and a little defect, no problem, then I would just bone graft that and be able to do that and not worry about so much of the loss of the bone distally. If you don't have enough talus, then similarly you have to think about doing a combined total ankle that is a custom total talus. And those can be made to match the existing end bone. So you only have to revise one side unless the tibial component is loose, which is very rare in the, inbone.
- [23:43]
A
How do you think your large experience in this report of that should impact our listeners?
- [23:49]
B
Well, there's a good article talking about a revision total ankles. And in this article, they did revisions. They did ankle arthrodesis and they did TTCs. And the TTCs came out very well in terms of pain relief, but not as good in function as the total ankles that were revised. So I think when I. When I look at an ankle that's not doing well and the patient's having pain at a level four or higher, I'm thinking the need for revision, bone grafting of the cyst, and I always trying to get more function. It's the same reason that I didn't stop doing ankle fusions. But I did ankle replacements. And people as young as 22 because they said things like, I would rather have an amputation than an ankle fusion, which is not realistic. But anyway, that was their psyche at the time. And so I always try to preserve that motion, even a little bit of motion. I always want to do a study, Charlie, and here's a challenge for you. I want to do a study where I take a cadaver specimen to the lab and I do an ankle fusion and then I do a procedure where I only have 5 degrees range of motion, and then another procedure where I only have 10 degrees range of motion and I want to measure the stress across the subtalar joint. So my hypothesis is that if we can get 5 to 10 degrees only the ankle, then we will reduce the stress on the subtalar joint by 90%. So that's my challenge to you and the audience to complete my goal with that experiment.
- [25:42]
A
Okay, I'll jump right on that one. Anything else you'd like to add?
- [25:49]
B
I would tell people that you need experience with the primary end bone. So if you want to do revision in bones, then I would certainly do at least 10 in bones. Before you embark on that, get familiar with the various components of the invision, which was just, just, just brilliant by those guys that worked for Right Medical and now Stryker. So a lot of engineering went into it, a lot of thought. It's an ideal prosthesis for revisions. Now, we do revise some ankles with single component problems. So I've revised the Vantage with a device that I thought of, which is a thimble attached to the prosthesis to make its stem longer and give it more support. So that's been a unique way to do that. And with the new prosthesis of the vantage with the stem on it, we're going to be able to do that. So I think the days of having to do an ankle arthrodesis, which is very difficult when you have a total ankle on a big void, and you're trying to put in a big chunk of femoral head or some large piece of metal to just do the fusion, that you might as well do the total ankle. So I would encourage everybody to think about that first and fusion or TTC later.
- [27:12]
A
Thank you, Dr. Diorio, for our most interesting podcast. Really appreciate it. I am Charlie Saltzman, editor of Foot and Ankle International Today. I've had the distinct pleasure of talking with Dr. Jim Diorio from Duke University, who's the senior author of this month's lead paper entitled Revision Total arthroplasty using the Inbone 2 system. Thank you for being on the program with us.