Good evening. On behalf of AOFAS, I'd like to welcome you to tonight's broadcast, 3D Printing and Foot and Ankle Surgery. Tonight's moderator is Dr. Kent Ellington, who's joined by Dr. Christopher Gross, Dr. John Kwan, and Dr. John Lewis. You can read their full biographies posted in the CME Program and Agenda document posted in the course online and will also be posted in this chat. Tonight AOFAS is proud to offer an AI-powered translation service in over 50 languages. To use the wordly AI translation services, use the QR code on the screen in front of you to use your mobile device or visit the URL on the screen. This link will also be provided in the chat at the conclusion of these remarks. The URL is also available in your confirmation email from Zoom. The 2024 webinars are provided free to AOFAS members and orthopedic residents, fellows, and medical students with funding from the Orthopedic Foot and Ankle Foundation, supported in part by a grant from Stryker. 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If we cannot get to your question during the live broadcast, faculty will reach out to you following the broadcast to respond. Finally, please visit the AOFAS website to register for upcoming events, including the AOFAS Winter Meeting taking place in January 2025 in beautiful Lake Louise, Canada. At this point, I will turn the program over to Dr. Ellington to begin. Thanks so much, Alina. I appreciate all your organization and work on this. I've worked with you for years and you do an incredible job for AOFAS and I can promise you this, that the majority of things would not happen at the Society without you and your team. So, just a big applause and kudos to you. Enough things can't go out to what you do for us. You make our job easier for doing these kinds of things and there's a lot of back-end work that gets done to make this happen and nobody sees it. And so, I just want to publicly thank you for what you do for us, so thank you so much. And then, there's a little bit of a seamless plug here regarding the AOFAS Foundation. I just had the honor of finishing a three-year term on the Foundation, on the board. It was an amazing life experience and a rejuvenation of what I learned about what the AOFAS Foundation does and what it supports in its mission. And so, with the recent leadership of Pete Mangone and the rest of the board members, including the president of the Society, the AOFAS Foundation does an incredible humanitarian and education mission and having sit there for three years, it's just inspiring what they do. And so, I donate yearly and I would challenge you to do so as well. So, let's see here. I'm going to give a quick little kind of quick introduction and then I'm going to turn it over to John Kwan to go first, then out of Boston, and then John Lewis out of Louisville. It's not Louisville for everybody, it's Louisville. And then, Chris Gross out of Charleston. So I'm based here in Charlotte. And so, unfortunately, Dr. Gross is not going to be with us live. He's going to be pre-recorded the lecture for us tonight and then we're going to show it tonight. He'll go last, but we definitely appreciate his contribution to tonight's education seminar. And so, you know, when we're thinking about 3D printing, we want to have something that maximizes surface area, porosity, end growth, own growth, and high strength and fatigue resistance. So, there's a lot of things. And so, what I love to show these slides and, you know, we are foot and ankle surgeons, we do foot and ankle surgery, we do, you know, relatively, we do some complicated, hard things, but there are some obviously some big orthopedic problems that are out there that require some big orthopedic solutions. You know, 3D printing has the technology to be able to meet the surgeon where the clinical need is and where five, 10 years ago, we had no solution to some of these patients that resulted in, you know, really devastating amputations, whether it's trauma, cancer, et cetera. We now have the ability to do some really amazing things. So here are some cases that I like to show. These are not my cases. These are trauma guys and cancer docs cases that demonstrate what the power of 3D printing can do. And I like showing it because I kind of joke like, hey, if we can replace half a femur, we probably can like, you know, fix a midfoot problem, right? Or a high foot problem or ankle problem. So these are the kind of things they can do. And I kind of joke that if your brain can think of it, they can do it. And there's a lot of companies that can do this. They all have different technologies and different IPs and different approaches. And I'd encourage you to research each one and how they may benefit your patient. But they could do some really, really big stuff. So here's another distal femur from a trauma. Here's a, you know, a custom glenoid and proximal humerus. Here's a custom acetabulum with a custom total femur approximately. Here's a fourth metacarpal hemipelvectomy with a total hip and another distal femur, another hemipelvectomy and total hip. Here's a distal tibia with a total ankle under it. Here's a patient of mine that had a previous total ankle that failed, that we had to do a custom total ankle. Another patient had a previous total ankle that failed, that we did a custom ankle fusion cage to deal with the problem. Here's a patient of mine as well that had Freiburg's and did a custom second MP replacement. And again, I'm just showing this real quickly to kind of make you start thinking about what Dr. Kwon and Lewis and Gross are going to talk about, how 3D printing can kind of start solving some problems that we used to think we didn't have solutions to. And so there's old school technology. If anybody knows me, they know I'm a pilot as well. And this is what I used to fly. And this is a Cessna 172. And that's a great plane and everything. I learned how to fly on that. But I've been flying for 11 years and I've kind of progressed over the years and I went from old school to new school. And so in orthopedic surgery, the same thing. We're not doing things we used to do surgery. There were times of surgery we used to do 10 years ago. And this is the old school plane. This is the avionics package from 1971. It's got a six pack and it flies planes, but it's pretty difficult to use. The steam gauges has a lot of problems and no redundancy, a lot of failures. And if one or two of these things goes down, you're in big trouble. But now this is my avionics package and this is the type of plane I fly now. Similarly, I don't use technology from 10 to 15 years ago. When I do surgery on patients, I try to use what's the latest and the greatest. And this is me flying over the earth and over the Bahamas. And so the point of that is, is that you got to keep training. You got to keep learning. And this is me doing high altitude loss of pressurization training at 28000 feet in the new plane where you only have seconds before you have to figure out what's going on or you're going to die or your passengers. Right. And so I just you know, we as orthopedic surgeons, our goal is to keep learning, keep you know, keep training, keep getting better. And the cool thing about 3D printing is it really is, you know, the new hot topic of what we do in orthopedics. And it allows us to really do some really cool things. But it has its limits. Right. So this is a patient I saw last Friday that came in and they wanted surgery. And I'm like, you know, OK, you know, as crazy as I am and as more, as much as I'm willing to push the limits, 3D printing could do some really cool things, but it can't do everything. So just to kind of create some options. And then quickly, in the hallux rigidus world, which a million people suffer from in our country, including me and my right foot, which bugs me off and on. And recently, the last couple of months, worse than normal. You know, what do you do for these patients? You know, we all know what the solutions are, but maybe we can look at it differently and start thinking about how we can use 3D printing to do hemi resurfacing of the big toe. These are a couple of patients showing, you know, thinking outside the box. And historically, orthopedic surgeons, we don't like this procedure because it fails. Well, the reason it fails is because the implants don't work and they don't grow to the bone. Well, if you have good 3D printing, you can start thinking about how maybe hallux rigidus could be treated differently and not just do a colectomy or not just do a fusion. And there's all kinds of ways to think about that. And but, you know, it's just again, I'm trying to get the juices thinking. So here's a patient of mine who had bilateral partial hallux NP replacements. And you can see she's wearing her four inch stilettos and she's loving it. And then, you know, if you do have a patient that shows up with a bad previous surgery with a failed implant, you know, maybe you can't do a partial replacement, but you got to do a distraction arthrodesis. And this is a patient of mine that had a custom 3D printed cage to regain the length of the of the first ray and also create a fusion. And this patient's over a year out with a successful outcome. No pain. CTs confirm fusion. So that's my quick little introduction. And we'll turn it over to Dr. Kwan to talk about total talus and things around that topic. All right. Thanks, Ken. Let me go ahead and share my screen here. All right. You guys can see my screen. All right. Yes. And thanks. So, well, I want to thank Kent for giving me the opportunity to talk. I'm going to talk a little bit about total talus. These are my let me see, hold on, try to advance my slides here. These are my conflicts of interest. Obviously, some of these companies are in the 3D printing sphere, but this is not really a talk about any specific company or implant. So this talk is really kind of my thoughts on total talus that I've kind of formulated over the past 10 years. And I have come down to, I think, four very important things to think about, especially if you're just starting to think about getting into utilizing 3D printing and total talus as a technology. This talk is not a comprehensive literature review. There are several papers out there. Sam Adams wrote a really good review paper a couple of years ago. And you can check that out. This is not an endorsement of any particular company. And truth be told, this isn't an endorsement for this treatment for the large majority of patients. OK. And so I think the first thing to really think about is indications and your indications for who you are doing this on. OK. You know, we we really many cases and many of these patients have some type of avascular necrosis. I have a couple of cases that had Taylor fracture, non-unions or even acute severe trauma. We'll talk about that. Tumor is pretty uncommon. But, you know, I think that if you are, you know, seeing a lot of patients that you're thinking about doing a lot of total talion, you know, your practice is probably very different from mine. Or, you know, you have to think maybe a little bit about indications. And, you know, I the way I think about this is does a patient have an end stage problem, but they have reasonable articular cartilage? And is there a time tested alternative surgical treatment that I can use instead of using a total talus? And then ultimately, when I'm thinking about each individual patient, I'm thinking, am I and is the patient ready to go down this path? And then what happens in X number of years if and or when this fails? And so this is a patient here. This is a 17 year old who was sent to me. She had an open extruded talus and she was washed out and put in an X fix and and had this spacer put in. And, you know, we all know that, you know, the options are limited for a young person like this. You certainly could do a bologna amputation. You know, my partner, Dr. Helene, would probably do a tibial calcaneal fusion and bone transport. On top of that, you could do a hind foot fusion. But, you know, I think this is a really good indication for a total talus. And so this patient is about seven years out and is doing pretty well with this. But, you know, not every patient should have a total talus. This is a Taylor neck fracture and you can see it went on to avascular necrosis. But this patient is 70, right? So a little bit different considerations and concerns. And so we did a fresh Taylor allograft and he had a hind foot fusion. And this probably was a better solution for him than considering a total talus. Now, you know, I have a handful of patients who have had bad Taylor neck fractures and they've had multiple surgeries. And in certain ways, you know, having a very educated patient is helpful, but but also one that really is, frankly, refusing certain treatment options. And so this is a 65 year old healthy attorney. She had several surgeries for her nonunion. And, you know, we talked about the different options and she went ahead and had a total talus and did fine. Now, this is a case that I did about 10 years ago. And again, another talus fracture. Right. But this is really pretty communicative. This is a really tough injury. And this was a 24 year old. So, you know, I did something a little bit unconventional. And I did a or F and a subtalar fusion at the same time. And the patient did well. But, you know, what is certainly trending is considering total tali as a primary treatment for bad Taylor neck and body fractures. And so, you know, the the history of total tali, I mean, the Japanese have really led the way for decades. And this was a paper that came out of Japan about four years ago that totally blew my mind. And they were doing total talus as the primary treatment for bad Taylor neck and body fractures. And, you know, at first, it seemed like a total wild idea. But, you know, we all know that these patients have a lot of complications, right, nonunion, malunion, avascular necrosis, subtalar ankle arthritis. So this is something that is trending and more and more in the literature. You can see some case reports where this, you know, the second thing I think about is what's the status of the articular cartilage? And, you know, there are short term, midterm papers looking at the longevity. But there are limitations of the literature. And I think the main limitation is, is I don't think we completely know who does well and who does a little bit more poorly with total talus. And, you know, I think if we can extrapolate from hemiorthoplasties and other joints, probably the status of the articular cartilage is very important. Right. Do they have arthritis or do they just have a bad talus and reasonable cartilage? And so, you know, I've gone to not only just CT scan for preoperative planning, but weight bearing CT and MRI and even arthroscopy, because I really want to get a good idea of what the articular cartilage looks like. So this is a patient. You can see that, you know, Taylor AVN ankle joint looks OK. The subtalar joint just looks kind of toasted. And this is what it looks like on the CT scan. Gives you a little bit more information. But, you know, an MRI gives you a lot of information, I think. And so aside from getting the CT scan, I know it's a lot of imaging. I'll start to get MRIs as well. And this patient had a total talus and did fine. Sometimes the MRI isn't going to be particularly helpful. This is a 24 year old who underwent this or AF and has a little bit of a bad anterior joint. You can see the CT scan is a little bit worse. But, you know, you can always take them for arthroscopy, which gives you the best look of the joint that you can get and do a debridement. And unfortunately, this is, you know, one of the unsolved problems in orthopedics. You can see the delamination of the cartilage, but her plafond actually looked pretty good. The third thing is, you know, planning. And, you know, I tell my residents and fellows, this is a pretty straightforward surgery, but it's not necessarily easy. Right. And there's ways you can make this easy. And I think that entails not only planning your implant, but planning your surgery as well. You know, if you have something a bit complicated, the planning with the engineers and work with the company is a lot of fun. Right. And there's a lot of different things that you can do with 3D printing, as Kent showed you. You know, this was a paper that talked about, you know, adding different features that you could do a lateral ligament repair on. We know that there's a lot of ligaments that attach to the talus, but no tendons. And but I found that in most cases that it's relatively stable. But this was actually an interesting paper that came out of my group and Japan that looked at the stability of total tailor prosthesis. And one of the key findings was as you downsize the implant, there was much more anterior posterior instability. And so I'm going to touch on this point again. But but of course, you know, the planning of the implant is a lot of fun. This is a and if you're doing more than a total tailors, if you're pairing it to a total ankle, this is one of Kent's cases, it really does entail a lot more planning in terms of what you may be doing with your subtalar fusion, your joint line and things like that. You know, one of the things that I like to do is I think that most of the handles on the trials are at a bad angle. So I don't know if other people have experience is kind of hard sometimes to get these trials in. What I learned is that if you drop the handle down, it's much easier to insert and I actually designed a handle that you can take off so you can take that ankle through a range of motion. One of the things I think to keep in mind is that these trials are nylon composite, right? So that the friction is different than your actual implant. And so what you very well may find is that you know, you put a 95% volume trial in and it feels pretty good and then you put the actual 95% implant in and it just feels loose. And that's probably not because there's a size mismatch, but just a coefficient of friction. So I do try to get the biggest implant in that I can and taking the handle off allows me to perform some range of motion. You know, the other thing too is you can do anything with 3D printing. So I would advise you to design a handle that makes it so that there's really no risk of dropping it on the floor. You know, the other thing too is if you have to get this out in the operating room, it's really hard if you don't have something that you can extract it with. And so, you know, just design a handle and that takes a lot of stress out of that part of the case. In the OR, I get full paralysis. I actually always have a femoral distractor in the room. I've had to use it once. You know, what's sometimes a little bit simpler is just putting a transcalcaneal pin in if you need a little bit more distraction on the calcaneus. You know, I'll do my TAL early and I think that, you know, you can plan your telectomy so it's successful, it's efficient, and you're not damaging any of the surrounding cartilage. And of course, don't drop the implant. You know, my last point is I think you have to be prepared for the next surgery. And when you have a total talus that you've done and the patient is having pain, you have to figure out why. Is it impingement? Is it where their cartilage? Of course, ruling in or out infection really changes your algorithm moving forward. And then, you know, at that point, does my patient want a surgery that continues to preserve motion? Do they want arthrodesis or something different? And, you know, one of the things that we're always challenged with is a patient who has a total talus and then their tibial plafont cartilage wears out and you might want to convert them to an ankle. But then you have a mismatch of your talar dome to your polyethylene. And so, you know, modular implants are actually really pretty interesting. This is my last case. And this just kind of speaks for, you know, with 3D printing, whatever your mind can think of. This is a 30-year-old who had a talar neck fracture, nonunion, multiple surgeries, and didn't want an amputation. And so, you know, we went ahead and did a total talus. And he did fine for a little bit, but he ended up having a wound dehiscence. And ultimately, he got his implant infected. And so the question is, you have a 30-year-old who doesn't want to BK, you know, what do you do at this point? And, you know, we basically went to the company and said, well, why don't you make us a 3D mold, a negative, so to speak, of our implant? And they went ahead and made this for us. And we put an antibiotic cement spacer in. And he did well. He got a radiofluorum flap, and then he's about three years out and doing fine. So, you know, we can maybe salvage more limbs if we do kind of more anatomic cement spacers. But again, with 3D printing, you know, whatever you can think of, you can do to the benefit of your patients. And so, you know, I think, you know, indications is probably the most important thing. Don't open a door you can't close. Think about the articular cartilage and maybe more advanced ways to assess how that is. Plan the implant and your surgery. And, you know, when you do this, you're burning the boats, right? So there's, you have to think about what your bailout and your next surgery is going to be to hopefully preserve the limb. So thank you guys. Appreciate it. Man, that was amazing, John. Thank you, John Kwan. Thank you so much. Really cool cases. And like I said, if you can think of it, they can do it. And you did several things I hadn't thought of before. So it's quite interesting. I look forward to John Lewis's talk next from Louisville. Thanks, Chad. John, can you see the screen? Yes. Yep. Yeah, thanks, Kwan. That was amazing. Really cool stuff and really tough cases. And I really liked your points about having tight indications. I think you showed some really nice things and really good decision making. So with my talk here, I was going to try to depart a little bit from the total talus. I think John covered that really nicely. Just kind of a more broader application of how custom implants and 3D implants can really help us out in foot and ankle surgery. These are my relevant disclosures. And so I think Kent showed some really nice cases in early on, where I think where the explosion of these 3D printed custom implants really occurred is in these massive segmental defects where you have significant bone or articular loss. And there's really no other option, either a very high amputation or a non-flail extremity. So it really started in tumor and then with trauma, segmental loss of bone. And so I think that's what people may have seen the most early on. And so I'll start with one of those cases when really nothing else will work. So this case, I inherited this case, came to see me. She had a history of multiple ankle replacements. She had her index procedure a couple of states away. It got infected. It got washed out, cement spacer, treated appropriately, treated with IV antibiotics, and then re-implanted. Unfortunately, that got infected. And then this is how she showed up to see me in Louisville. And she had already had an aspirate showing she was infected. And these were her radiographs. So she obviously has a stemmed intramedullary tibial implant, but the tailor component's having problems. It's either fairly significant posterior slope or just erosion of that posterior tailor body. It looks like that tailor component's probably in the subtailor joint and potentially articulating with the superior aspect of the calcaneus. So the first step, in my opinion, is not a hard decision making. This all needs to come out. We've got to get a hold of her infection. It was unclear to me at this point whether she had an initial infection that was never totally cleared or if she developed a new infection. And if we look at her implant, so that stem is well ingrown. Those are fairly beefy segments in that implant. And this was a fairly small lady. And the superior medial aspect of that implant was completely spot welded to the whole distal tibia. So it was kind of a nightmare to get out. I did this before some of the newer extraction sets were around with the circular trefines. So this was just kind of a bear to get out. Ended up getting it all out. Ended up fracturing the distal medial tibia because it was spot welded to that area of the bone. She didn't have any residual tail or body left. And half of her tail or neck was gone. That implant was sitting on the calcaneus. So I treated her with antibiotics. Antibiotic spacer. Treated her with six weeks of IV antibiotics. Gave her an antibiotic holiday. Her wound healed great. And so she's coming to me like, what's the next step? And also she was developing not only significant varus radiographically, but clinically you could just see her in a fair amount of varus there. So it's a tough problem. Elderly lady, two infected total ankles. She now has a chronic distal tibia, non-union, moderate varus deformity, and really no residual tail or body. So I think, you know, x-rays tell you one thing, but you really have to look at the whole story. I think, you know, without the history of infection, you could maybe think about trying to do an arthroplasty reconstruction with potentially a tailors replacement component as Dr. Kwon had shown. But in my opinion, this lady had kind of had her run at the ankle arthroplasty. This was my first go around with her and I didn't think she was a candidate for re-implantation for arthroplasty. Obviously any kind of revision with an arthrodesis doesn't completely eliminate the infection risk, but I thought her infection risk would be lower with a conversion to an arthrodesis rather than another arthroplasty. But she's got fairly significant bone loss. And this is where John touched on, really the meeting with the engineers can be fascinating. They have a lot of experience in this area. And again, there's multiple companies that can do this for you. And they'll do literally whatever you want. You know, you kind of tell them your basic goals and ideas and they'll kind of go through it and model it for you real time with CAD drawings. And you can kind of figure out what's going to work. So for this particular patient, I wanted to basically remove that whole non-united bone, get rid of any of that posterior tibial bone that was still there, freshen up the distal tibia, try to get rid of any nidus of infection, the residual bone and the distal metadiaphysis. And so this is kind of what we came up with. And you know, most of these companies, they exist to make your life easier. So they create custom tools, custom guides that can just make these surgeries so much easier than they may potentially look before you get started. So, you know, we just decided where we wanted to have our tibial resection and they printed a custom guide to make that tibial resection. And this was the custom implant that we had come up with. And, you know, it doesn't, you can kind of design it however you want based on what you need, what the patient has and other characteristics. So for this, the reason this looks like this is obviously the height was set on the amount of tibial and tibial bone expected to be resected. Her tailor head was alive and viable. So rather than eliminating that and then having a hemiorthroplasty type articulation of the tail vicular joint, we created custom holes for fixation to attach this to the residual tailor head, which was still alive. For my surgical planning for this, I elected to keep the fibula because I felt when I removed all of that tibia, I didn't want the legs just to completely lax and floppy with the neurovaginal bundle everywhere. So I elected to leave the fibula. So the lateral aspect of that implant is smooth. And the medial aspect is smooth as well to allow, you know, that, you know, this is essentially a tumor case at this point. So that neurovaginal bundle and those tendons are coming poster immediately, you don't necessarily want them on an ingrowth surface. And then we put an ingrowth surface wherever we wanted bony ingrowths. And so this is intraoperatively. And again, you know, these cases are often not quite as hard as you expect based on all the tools they give you. So it was fairly straightforward to resect the tibia with the custom cutting guide with guide matching, just like PSI for any total ankle arthroplasty. The trickiest part was shelling out all that posterior tibial bone that was left without cutting everything in the back of the ankle. This is the one time foot and ankle surgeons get to use a tab reamer, which is always fun. So this is the smallest tab reamer. Sometimes I'll happen to have to open the juvenile set just to quickly prepare the top of the calcaneus. And again, there was no talus, so I was just reaming the top of the calcaneus. These are the nominal trials, you know, for this big of a defect that handles pretty easy to use. I think Dr. Kwan's points are pretty well taken with a total talus. And, you know, they usually give you the size that you think you're going to use, one bigger and one smaller, and you can kind of decide what fits. This is how I pack the implant. So I packed every engrossed surface with allograft. Those kind of white paper-looking things, that's actually infused, which is technically an off-label useless indication. But in these cases, you know, the next step, if this doesn't heal, is an amputation. And so we've had very good results in salvage procedures with that product. And so that's why I elected to use it here. And this is implanted. So you can see it's hard to see a lot of the cage because I packed it with so much graft, just trying to get something to heal. And you can see where I have that custom holes in the front to connect the cage with the residual tailor head. And so that's what it looks like on radiographs, you know. So I was pleased with how we were able to correct all the varus, kept her out to length, had pretty good cortical contact above and below, and was fairly pleased intraoperatively. Hind foot was well aligned. And she did really well. So, you know, she's now about two, two and a half years out. She's walking in normal shoes. She's not as happy as she would have been if her index total ankle had worked. But she's a lot happier than she was before we started down this path. Her wounds healed, no sign of residual or recurrent infection. And this is a CT about a year and a half out, which is kind of nice, just showing, you know, nobody knows how much we expect this bone to grow into these cages. It's probably not ever going to completely grow all the way through the cage, but, you know, a centimeter of ingrowth seems great for stability. And so the CT shows that that bone is really, you know, that residual tailor head was a little bit worried about the viability. You know, I made sure it was bleeding and it healed pretty well to that, to the front of the implant. And you've got a lot of bone that's crept down into those ingrow surfaces, approximately at the, at the tibial cortex. And so this was just a case, just kind of showing where there's really no other options. So it's pretty, pretty obvious in these situations, if you're not going to do an amputation or, you know, something like a bone transport, like John said, you know, these are really the best options. These are also quicker recoveries than something like a bone transport. It's kind of a one stage procedure. But now I just want to kind of touch on where customs, I think this is talked about less, where customs can make more routine cases just easier. They provide options for you as a surgeon that you may not have access to with off the shelf implants. And when you just kind of get used to using these implants and the power of creating literally whatever you want, you can make some particularly daunting or arduous cases a little bit easier and maximize patient outcomes. So here's one, this is a 44 year old female came to me. She four years out from a bone block, subtalar arthrodesis. There was a reported history of a plantar talus fracture. I'm not sure what the indication was for a subtalar bone block fusion, but that's what she had. And that surgeon used an off the shelf, off the shelf Evans allograft wedge. And she showed up and saw me four years later. Her main complaints were pain and she had a fairly fixed forefoot supination. She had trouble getting her medial column of that tripod on the ground. And that bothered her as much as the pain in the hind foot. These were radiographs and the CT shows she obviously has a non-union. It's really a corticated non-union. You can see some of that incarcerated graft material from assuming that's just dead allograft bone from the prior wedge. And then if you look at that axial cut of the forefoot, now this was not a weight bearing CT, unfortunately, but this was a pretty accurate assessment of her foot like when you were looking at her, she had that significant supination and that bothered her as much as anything. So this patient corticated subtalar non-union, incarcerated allograft wedge that had failed, fixed forefoot supination. What are our options here? Oh, also she's a physician's wife. So super nice guy, but he's worried about his wife and he's looking at you like, how are you going to fix this? How are you going to make this better than what she had before? Which was done by a really good surgeon. So what are the off the shelf options? So in the past, you could think, I mean, some people may do this now, but in the past I've seen contoured tricortical allografts. That's technically difficult in my opinion. You're trying to hold onto the wedge while you're trying to cut it with a saw and you're hoping it doesn't spit off the table or cut your fingers. And then you're also just using dead bone again. Iliac crest autograft. So for something like this, you'd have to take a structural graft from the Iliac crest. I almost never, and by almost never meaning never do that anymore just because the donor site morbidity is not worth it. If this was my foot, I would not want somebody to take a big wedge of my Iliac crest to fix my hind foot. So what else? But of course that's a good option. That probably has the best healing option. You have viable bone from the host. Or you could try another off the shelf wedge. It already didn't work. Maybe try again. Or sometimes in the past we've taken cones from the tibial augments, stole them from our knee colleagues and stick those in there and hope they work. But obviously that's not what they were designed for. And so you're going to have some problems with that as well. So this is one where I felt like a 3D implant was really going to help me. I could really plan the deformity, correct the deformity. If I'm going to put an inert substance in there, you know, dead bone versus metal, I'd rather have the structure of stability of metal. And she'd already failed an allograft. So this is her preoperative anatomy. And interestingly, she didn't have like a bad cavus or a bad varus deformity of her nonunion. It was more of a translational deformity. So I still wasn't entirely sure where her forefoot subunation was coming from. But with this type of templating, it's very easy to plan your correction. And so my plan was to resect the joint and all that incarcerated graft material. I thought it was all dead, corticated bone. I didn't think it had any propensity to heal. And so you can come up with the engineers with these wedges that are every dimension you want. So you'd note the wedge is, it's not uniform in any dimension because we wanted it planned for the resection to match the correction. So the heels are neutral without that translational deformity, which this is so hard to do, contouring an allograft or even an autograft by yourself just on the back table. And so this was intra-op. And so the trick was, so I had signed her up for this procedure, but also I felt like I was gonna have to do a cotton or something, her hind foot deformity. I wasn't sure if I corrected that deformity, it would really fix her forefoot supination. And so then I was stuck with a positioning problem. I often do these cases from prone. It's kind of easier to go in there, take out that posterior joint, slip the wedge in, but it is very hard, if not impossible, to do a cotton prone. I don't know, Dr. Kwon could probably do it, but I didn't think I could do it. So I actually did this sloppy lateral, which was the hardest because it made both procedures more difficult. But positioning's a big thing too. You gotta think about everything you may have to do. And so I sacrificed a little bit on both procedures for this and did a sloppy lateral. And so I didn't show them, but obviously they create cutting guides that you pin there and you can cut them out. Honestly, I freehand these a lot of times if I have a good sense of where I'm going. It's just a little quicker and easier if you have a good, after looking at the plans, you have in your mind's eye where you need to make the cuts and then corrected her deformity. You can see on the axial heel view, there's no more translation issue there. Appears to be in physiologic valgus, but she still had this forefoot supination on simulated weight bearing. I couldn't leave her like that. So from the lateral position, ended up doing a cotton wedge. And this is a 3D printed implant as well. It's not custom. I didn't think she needed anything custom here. She just needed a pretty good cotton wedge. And she ended up doing better than expected. She was set up for failure and she ended up doing really well. She's about five months out. She has no pain. She's told me that her foot feels better than it has in 10 years. Her husband's happy. And so all is good. And I'll tell you the surgery, I think would have been much more difficult without the tools that not only just the implant gives you, but all the tools that 3D printing and customs can give you to make a difficult procedure more palatable in the OR. And you can see even at five months, she's really forming bone. You know, it's hard to see bone going through the wedge without a CT scan, but she's consolidating a ton of bone posterior to the wedge. So I think that's a good sign. Another case shifting gears a little bit. So this is a 57 year old female who came in to see me, sent from, you know, she lives a couple hours away in the country. She runs a food truck. She's very nice. She's extremely small. She said she was five one. I can't imagine she was over five feet. And these were x-rays, you know, sent to me because her ankle hurts. And so there's obviously a lot to unpack here. You know, she's got fairly significant posterior tibial tendon dysfunction with a lot of hind foot deformity, a lot of mid foot abduction. And, you know, we can debate for hours about how much valgus is acceptable without doing a deltoid allograft reconstruction. But for me, this tipped at scales that I would treat something like this with a stage procedure. So initially treated with a stage procedure for the realignment, double hind foot arthrodesis, formal deltoid allograft reconstruction with cementarthroplasty of the ankle to correct her alignment, reset her tension, and really set the stage for an ankle replacement, which is what she wanted. So, you know, as long as you do this, this stage correctly, the total ankle when you come back is pretty much a walk in the park. Now, this patient I learned early on was gonna torture me. She was horribly non-compliant, showed up without her splint, walked on it from day one. And for some reason, she healed everything. She did great. You know, I felt for sure she was gonna have a non-union. Was pretty happy with her deformity correction. Her ankle was very stable. You know, slight residual valgus, but overall pretty well corrected. And she healed everything. And this patient, I really didn't, wasn't super excited about operating on again, but I'd put cement in her ankle. So I was kind of in it for the long haul. I had to, I couldn't leave her like that. So now for somebody like this, why a custom implant? So you look at her ankle, all the deformity has been corrected. It's theoretically stable. This is a chip shot total ankle. But there are a couple of things about this that drove me to a custom. One, the patient was extremely small. So we did some standard templating with preoperative planning and the smallest available size off the shelf was too big. The tibia overhung a lot, both the anteriorly and posteriorly. And that was a big concern for me. And that drove me to think about more of a custom implant given the size constraints of the distal tibia. Finally, since I had been pushed to use a custom, now I kind of had free reign to do what I want. So I wanted to achieve some increased tibial fixation without violating that allograft that I'd put in just four months ago. So again, the total ankle was not that difficult. She's already lined up. You can couple the cuts pretty easily. And this implant, so at the time of this case, this is a custom size zero. So this is the smallest implant the company's ever made. And you can still see it's a little bit long in the back, but this implant is smaller than anything on the shelf. And at the time this was implanted, this was a custom implant. That increased tibial stem is now actually commercially available off the shelf, but at the time of this case, it was not. And so I was able to harness the power of the engineers being able to do whatever I wanted to get a little increased fixation. Again, she continued to torture me. She showed up after that, even after reading the riot act, she fell, splint was off, here are x-rays. And so she had suffered, I often will protect that medial mal with a screw when I do a total ankle. I didn't wanna violate that deltoid allograft and I paid for it. And she broke right through that deltoid allograft reaming. I also had to do a brostrom at the time of surgery. Often I've found these patients have some degree of global instability. You go back to do the ankle replacement and you're like, oh man, I hope it's stable. I hope that deltoid is stable, but they often need a brostrom as well. She tore a brostrom. So it took, and you can see on the CT scan that fracture went right through that reaming where that deltoid allograft was. So took her back one more time, told her this is it. If you don't follow directions, I'm not gonna have much left to offer you. I'm gonna have to send you to Charlotte or something. And this is, again, she was so small, no distal medial tibia plates fits. This is actually the smallest posterior fibula plate I could find. So I get a cluster distally, repaired that medial mal, redid her brostrom, and she finally listened to me and finally did well. She's done extremely well. So she runs her food truck, brings me food all the time, and she's very happy. But this is one where the case itself isn't difficult, but there's just certain things where 3D implants can give you an advantage over what's available. You could make it work, but that's not necessarily, in my opinion, the best thing for the patient when we have some of these options available. Last one, real quick, again, 74-year-old female, see these x-rays all the time, prior tibial malunion, a little bit of deformity. Again, this is a chip shot, total ankle replacement, in my opinion, but the problem was documented cobalt chrome allergy. She'd had both of her knees revised to auxinium. And she was, you know, she's one of those very believable patients. She didn't have a hundred allergies. This was the only thing she was allergic to. And she was like, listen, doctor, if this is all you have, I will do it. I'm just worried about it. And I think in the past, you know, we've probably all done some total ankles in patients that said they had a cobalt chrome allergy and they've done fairly well. But for this patient, because of what we have available, I did an implant that was just all titanium. So there's nothing special about the implant or the case other that the implant's totally titanium to help avoid any issue with metal allergy. And she did phenomenally well, you know, realigned her, you know, PSI. You can navigate that tibial malunion pretty easily and she's done very well. So 3D printed implants, you know, I think in my practice, they serve a lot of purposes. One, they provide solutions in catastrophic situations where no other solutions really exist, massive bone defects, but they can also just make very difficult procedures technically easier with more predictable correction and outcome, particularly for deformity cases, revision cases. The pre-op planning is immensely helpful and in the OR it can help you a lot and just help you provide that correction so you're not trying to use an off-the-shelf implant that isn't even indicated for that procedure or just routine cases where the cases themselves aren't difficult, but there's a wrinkle, they have an allergy or just something's wrong. And so it's been very helpful in my practice in certain situations. So appreciate the time guys. Well, ladies and gentlemen, we'll hand it back to Dr. Ellington. Thanks so much, Lewis. Holy smokes. I tell you, there's just some tough, tough cases that you and Quan showed and not trying to promote a specific company or technology, but I just am strongly opinionated that this type of technology gives us so many viable options that we used to didn't have. Some of the old people in AFS, I've had some conversations with them and they're like, just cut the leg off. And I don't know, I think that's always an option. And if these don't work, then sure, but the vast majority of these custom cases and these challenging cases actually do work. And I'll tell you, those cases you showed, Lewis, were not so, definitely don't send that lady to Charlotte, but kudos to you and those successful surgeries. So then, okay, Gross is next. It's a prerecorded video and we're gonna switch gears here. So we just showed you different metal cases from a variety of companies and this is gonna be a different material. It's gonna be talking about PEC. Hi there, my name is Christopher Gross coming to you from the Medical University of South Carolina. I'm a professor of orthopedic surgery there. I'd like to thank Ken Ellington for inviting me to be on this panel today and the talks have been incredible. Today, we're gonna be talking about PEC, not peak, but PEC, which is a new kid on the block in terms of 3D printing applications for foot and ankle surgery. Okay, so I'm gonna try to make a case against metal. And again, as orthopedic surgeons, we absolutely love metal. I use metal every day I operate. However, there is something to be said about what we leave in patients can influence their health. So we know from joint literature that there are adverse reactions to metal debris. There are local cytotoxic events, which creates an inflammatory response. And sometimes that inflammatory response gets so bad that there's systemic toxicity and metal hypersensitivity. And here's an illustration on the right, which demonstrates the coating and metal particulate matter can be micronized and cause harm in the local soft tissues. There's a 2019 FDA report focusing on metal and alloys that demonstrate that there can be long-term effects from metal in the body. So we know that all metal corrodes in the body over time. And as that happens, products move throughout the body. It can cause osteolysis around implants, infection, loosening, and pseudotumors. So these adverse global effects can be toxic and it could include pro-inflammatory and immunogenic reactions. And we know that cobalt chromium in some stainless steel and titanium can cause local and systemic effects. So what kind of metalware are we seeing in ink replacements just as an example of current literature state? So we have pitting and scratching, just regular metal debris, abrasions, delaminations, striations, and surface deformation. And we're seeing that in a lot of the ink replacements that are on the market currently. Obviously, we're talking about 3D printing today. And we do this because sometimes we're left with large defects or in cases of short-core arthropathy, poor bone quality. The great thing is these are patient-specific custom sizes that cannot collapse. They have stronger mechanical properties than the biology, the local native biology. And there's going to be certain coatings for bone growth, osseous integration, and hopefully an antimicrobial effect. And Sam Adams has pioneered a lot of this early literature. Looking at 3D spherical implants versus femoral head allografts, looking at the rate of graft resorption is significantly lower, which is basically zero, than the femoral head allograft groups. And the good thing is there's no difference in complications. What's interesting is that the total fuse articulations is significantly higher in the 3D printed group than in the femoral head allograft group. But what are my 3D printed options in terms of what can we 3D print and then put into the body, at least in foot and ankle? Titanium, we know and we love. It's highly resistant to corrosion. Modulus of elasticity is close to bone. It's a high strength to weight ratio. And when this titanium oxide layer forms, it allows osseous integration. However, we know that tantalum is highly osseointegrative, but it's very expensive and hard to 3D manufacture. So additive manufacturing is very hard. Cobalt chromium alloys, again, ideal for load-bearing implants, but significantly heavier than bone and can cause some stress shielding to bone locally. And some other biodegradable metals like magnesium and zinc have also been 3D printed. And now we'll get to PEC, which is... So what is PEC? PEC is polyether ketone ketone, and it's not PEEC. It's very important. Similar, but very different. It's biomechanical, antimicrobial, and it's the first bioplastic that we can print on a massive scale that allows for osseointegration. The elastic module is more favorable than titanium. You can 3D print these implants in like three days. So it's significantly quicker from production. I'm sorry, from conception of production of putting it into a patient. And it has a lot of decreased wear debris relative to metal. So here's some unique product features. Again, just more in a cartoon environment of PEC devices. When looking at the biomechanical properties of 3D printed PEC, it's superior to titanium and PEEC. It's more similarly related to bone in its density, modulus of elasticity, and yield strength. Now, obviously titanium is stronger, but you want something that is going to be mimicking bone for bone to scaffold onto and create more bone and eventually fuse. So when it's 3D printed, again, the performance characteristics are most similar to bone. And when it's extruded or molded, the PEC actually has superior mechanical performances to PEEC, most notably in compression. So in terms of osseointegration, when we're looking at titanium coated versus PEEC versus the PEC implant, we noticed that the PEC implant has residual bone attachments to the sample after a pushout test. So there is, in an ovine bone defect model, more osseointegration. Another osseointegration study in an in vivo analysis, looking at the PEC versus machine PEEC. So you see that there is, in the PEC, strong evidence of bone on-growth into 3D printed PEC versus no evidence of bone on-growth with PEEC. Again, looking at PEC versus PEEC, on-growth and fixation, you're gonna see a significantly greater tissue response after 12 weeks in PEC versus PEEC. Again, you're going to see bone grow into the PEC and it will not grow into PEEC. And here is in a rabbit jaw model, basically looking that 3D printed PEC as a scaffold can have bone grow into it. And it just demonstrates that PEC can be a scaffold for bone. It also has some very unique antimicrobial properties. So with PEC services, it provides an inherent antimicrobial environment. And basically, when you compare it to other materials, it has a 40 to 50% higher antimicrobial effect. It has greater absorption of proteins such as casein, mucin, and lubricin. And then it does not grow bacteria on it. So when you try to grow viruses and bacteria on it, it just simply cannot attach. When you're looking at this 2021 study findings, basically there's significantly decreased colonization of antibiotic-resistant bacteria on PEC relative to PEEC, titanium, and then polyethylene. Again, one of the great things about not using metal is that you don't have any metal particles. There is no corrosion, no matter the lamination, no metallosis, you're not seeing these huge responses in the body when you're removing this or exploring around the implant. And it is radiolucent. Again, that can be important for monitoring such as in this instance, what the joint is looking like at the tibiotailor joint versus that subtailor joint, or if there's going to be any osseointegration, you'll actually see the bone grow into the implant itself. And here you can see a video of the fact that this fusion sphere made of PEC can actually wick fluid against gravity. And so this is important when we want this implant to be seeded with proteins or stem cells that are going to be required for healing. Thank you. There already is an existing cranio maxillofacial process and just an example here. So you upload the DICOM data, you have a planning meeting, then the engineers get to work, they create everything, you print the implant and then you put it into the patient. This has happened at least I think 3,000 times in cranio maxillofacial patients. All right, so I'm gonna present a couple of case examples to just demonstrate to you the power of this technology. So this is a 50 year old gentleman, diabetic smoker with an A1c of 12.5. He is an alcoholic as well and did not know that he was neuropathic and to be fair he didn't know that he was diabetic either. So he presented with these initial injury radiographs here and you see that he has a pretty bad pilon. Okay, now knowing that he was a diabetic and a smoker and a neuropath, I elected to perform an ankle fusion in him. Now granted I could have been smarter in my decision of performing an ankle fusion, should have done a TTC fusion, but regardless. Here are his intraoperative fluoro images. I think we did a pretty good job of you know putting the joint or at least you know getting a construct able to allow him to fuse. Unfortunately the patient showed up at a six-week post-op without pain. Obviously he had been walking on it and he was ready to get back to work as a line cook. Then I told him, hey hold on let's go get some x-rays before we get too excited and this is the disaster that I saw. You can see that the fracture propagated above the plate and obviously the hardware is doing nothing. Intraoperatively we determined that there was also a risk for infection so we had to perform a debridement and irrigation. We had to put in an antibiotic spacer into the patient and basically keep him out to length with a frame while we treated him with IV antibiotics. This is the patient roughly six weeks after we performed our debridement irrigation and I knew we had to do something. He did not want to lose his limb so we had to come up with a better reconstructive option for him. So here is a CT scan of this patient as well and here are the intraoperative fluoroscans of basically what it looks like in vivo and I'll show you a more specific example later. But it looked pretty good. Here is at four weeks post-op you can actually see the bone starting to grow posteriorly and medially using the cage as a scaffold. Three months post-operatively he's having zero pain. The implant is looking nice. Again you can see the outline of the implant encased in bone. Four months out here we are and again no pain. He's walking on this without difficulty. And then we have CT scans demonstrating that the patient has osseointegration and it's quite phenomenal. We can actually see the bone growing onto the implant through the implant. All right and here's just you know a cartoon representation of this case. So at eight months follow-up we have our final x-rays there. Here's another patient who's sent to me by my partners. 65 year old female with a pilon. She got infected and they had to remove her hardware and she has a significant amount of arthritis in the tibial-talar joint but more significantly a large dead space and dead bone. Here are her initial post-operative images. They did a nice job you know with a smashed distal tibia. Unfortunately she started to have pain, swelling and then they had to take out her hardware and wash her out or put her on six weeks of IV antibiotics. So that is after the hardware was removed and this is what we're left with. Shows she has significant pain. There's not enough bone to do a ankle fusion or TTC fusion and you know there is just a big hole there left by you know the dead bone that they had to remove after the hardware removal. So this is what happens when you send the CT scan to the company that provides the 3d printed pack. Basically these are some the design PDF. So this is the preoperative anatomy of the patient. Here's the proposed anatomy resection. So we're going to be removing a significant amount of the tibia simply because it's it's it's rather non-existent but also it's quite dead. And then again I wanted to preserve as much talus as humanly possible so I elected to perform a flat cut on the talus as opposed to removing it in its totality. You know again the more bone that we can spare despite the fact that we're doing quite a number on our tibia more bones we can spare the better. It preserves blood supply and allows for better and long-lasting healing. And here's what a nominal trial looks like shown in the native anatomy after you remove the implant. I'm sorry after you remove the tibia. And this is what the implant looks like. So you see this honeycomb like structure on the outside. We're finding that when we're 3d printing this that's where the bone is going to be used as this is going to be using the hexagonal structure as an scaffold to grow along. Inside there is a solid core to provide increased strength and stability. And you know you can put whatever you want through this hole. We elect for 15 millimeters so it gives you some wiggle room one direction or another. And this is what it's going to look like in the in the patient. Now what's really cool is that you know the next few slides we're going to show you theory into practice. All right so here's the patient after we get rid of her tibia. Again the distal tibia is extremely sclerotic. I'm using the nominal implant to mark out where I'm going to be placing my saw and my saw cuts. Here's me performing said saw cut. And this is as we were going to remove the distal tibia. Okay so now that we removed the distal tibia I'm going to match the defect with the trial implant. And here's what the trial implant looks like when it's in the patient. All right here are just some intraoperative photos of ensuring that the nail is going to go in the right position. And then here is us loading every single biologic that we can think of onto the implant and into the bed itself. Again there's crushed cancellus, there's autograft, there is BMP, there is stem cells. And the important part is packing the posterior aspect of the joint with a large amount of bone graft. And after that I'll put like a little blanket of BMP on it. And here's the implant in the patient. What the positioning is going to look like from the top down and what you're looking at. And these are the final x-rays of the patient. And again we just did this case on 11-14-24. So this is fresh off the press. Here's another patient that was unfortunately we did a an external circular external fixator on her after a Charcot reconstruction because she was going to walk on it. She developed severe osteonecrosis and infection in her distal tibia between the rings of her circular external fixator. So I took out that dead bone. I placed an antibiotic coated nail in an antibiotic cement and then immediately post-op you know these were her images here. And now we actually have four month post-operative pictures would demonstrate complete healing. We are getting a CT scan on this presently. But all this shows you is that the technology is moving along. We are always exploring different materials that the body can work with and heal. Thank you very much for allowing me to present this to you tonight. If you have any questions please feel free to reach me seagross144 at gmail.com. Thank you. Okie dokie. So that was a great cases by gross appreciate that and a nice way to look at things in different ways. Same kind of problems same kind of approach just using a different material and thought process. So very cool to see that. And so we ran over a little bit. It's just now 1008. I'm sorry I sound like a train wreck. Sick. We have had some questions. If anybody has some other questions please feel free to ask. And one question we did have was about approval process. Obviously every every situation every institution is different. These are challenging cases. Oftentimes the price of the implant or custom implant can be similar to or even sometimes a little more expensive or even sometimes even cheaper than some of the allograft options that we have on the shelf. So something to take a take into consideration to your value committee. And then obviously below an amputation that cost extrapolated over decades of someone's life is pale in comparison to what an expensive custom implant would cost. So prosthetic legs and arms are 10 to 100 times X more expensive than these custom implants over a lifetime. OK. Elena thank you so much. Dr. Lewis Kwan and gross. Thank you for your expertise insight experience and thoughtful presentation. You make all of us better. So thank you so much. Thank you. Thanks Ken. Thanks John.

3D printing

foot and ankle surgery

custom implants

total talus replacement

avascular necrosis

articular cartilage

PEC material

biomechanical properties

limb salvage

orthopedic surgery