CME OnDemand: The ABCs of WBCT - Incorporating It Into Practice and Research-The ABCs of WBCT: Incorporating It Into Practice and Research

The ABCs of WBCT: Incorporating It Into Practice and Research

Video Transcription

Good evening, on behalf of AOFAS, I want to welcome you to tonight's program, ABCs of Weight-Bearing CT, Incorporating it into Practice.  Tonight's webinar will be moderated by Dr. Cesar De Cesar Neto. Joining him is Dr. Nassimi Mansour, Dr. Alessio Bernasconi, Dr. Matthew Conte, and Dr. Francisco Lintz.  You can read their full biographies and disclosures in the program document posted in the chat box and in the on-demand education center.  They're also posted here, and I'll pause for a moment for you to read them.  The 2023 webinars are provided free to AOFAS members and orthopedic residents and fellows with funding from the Orthopedic Foot and Ankle Foundation, supported by grants from  Arthrex and Stryker. With your support, the Orthopedic Foot and Ankle Foundation funds education, research, and humanitarian service trips.  Donate now by texting GIVEAOFAS to 41444, or you can scan the QR code on your screen.  Registered physician attendees may earn one hour of AMA PRA Category 1 credit by completing the evaluation and CME claim form at the end of the webinar.  You can find the link to claim CME in the chat tab, and we'll follow up with an email following the conclusion of the broadcast.  This webinar is being recorded and will be available in the on-demand education center content library in approximately 24 hours.  For technical difficulties, try closing your browser, logging back in the same way you did the first time. We encourage you to ask questions during the presentations.  To send your question to the faculty, click on the Q&A tab on your navigation bar. If we cannot get to your question during the live broadcast, the faculty will reach out  to you following the broadcast to respond. At this point, I'll turn the program over to Dr. Netto to begin. Hello, hello. Good evening, all.  Good morning to the people in Europe, including Alessio, one of our speakers. Thank you all for being here. I'm super excited, of course, for obvious reasons for this webinar.  It's one of my main passions, weight-bearing CT, so we're going to be talking about the ABCs of weight-bearing CT and how to incorporate it into your practice and your research.  Like Alina mentioned, we all, most of us have conflicts with this, and I do have conflicts  with weight-bearing CT, and here are my conflicts, and I highlighted the ones, the most important ones for you guys there. So a lot of people ask me, how did you start?  I mean, where does weight-bearing CT came into your life? And it's actually, there's not going to be time to tell all the story here, but it came from Dr. Sean.  When I started doing research with him back in 2014, he told me, go to my office, look at my whiteboard.  You're going to see all the research that is going on there, and you can pick anything that you see in that whiteboard, and that's yours. You can take the lead.  And then I got to the whiteboard. That was kind of the whiteboard. And then I'm looking into the tons of stuff going on, and a messy whiteboard, I found  that word there, and I said, weight-bearing CT, I didn't even know it existed. I said, what is that? But I loved it.  I loved the fact that a CT scan could be done with weight, and that's the way I jumped into it. And I think some things are meant to be, and I think that happened for a reason.  Then the tough part came, and Dr. Sean told me, if you really want to do this, you're going to go to Hopkins, and Dr. Demare is a radiologist at Hopkins, and he's got the  weight-bearing CT, so you're going to have to bring patients from MedStar Union Memorial Hospital into Hopkins to get the CT scan done through an IRB.  And here I went to get to know this machine, and that was the machine that they had there, a prototype of a weight-bearing CT, and it was definitely love at first sight.  And that's how it started. It was by chance. We started by doing a brief literature review, and we decided we'd use it for flat foot deformity.  We thought it would be an obvious way to start it, because flat foot, you have to put weight to be able to see the deformity.  And this was actually a print screen of the discussion of the first research meeting that  we had with measurements of PTT dysfunction at that point, and we were using the terminology. After that, then Dr. Richter, that was for sure, Martinus Richter, past president of  the European Foot and Ankle Society, he was probably the one that brought us all together.  So he started in this European Foot and Ankle meeting, where he put together a session about weight-bearing CT.  There was a few people in the world doing research, and you will see some familiar names here. Francois Lins, one of our speakers today, Arnie Burson from Belgium, for example, and  that was the picture of the first meeting that we had. We have a session of only weight-bearing CT studies, and you can see Francois there, you  can see Professor Richter, you can see Arnie Burson, and actually Dr. Saltzman was there as well.  And that was the embryo of what ended up becoming, first, the Weight-Bearing CT International  Study Group, that later became the Weight-Bearing CT International Society, that if you guys don't know, I would recommend you guys to check on it and become a member.  This was the first paper that was a review paper published on what was available with the literature, and I want to use this opportunity to remember Alex A. Barg.  If he was still with us, he would definitely be in this webinar, and he was a strong proponent and a great friend that we will miss eternally.  So then we go for all this Weight-Bearing CT stuff brought me together and made me friends for life. So first speaker, Francois Lins.  You can see him when he came to visit me when I was a fellow at HSS in New York City, and then he was wearing a Hawkeye jersey when I brought him in Europe, Francois is in Toulouse,  France. He has tons of publications, a very prolific publisher and researcher, and he's going to be talking about Weight-Bearing CT, what is it, and how did it start.  Second speaker is Alessio Bernasconi from Italy, University of Naples, Federico II. Here's Alessio, also visiting us when I was at HSS, watching the Brooklyn Nets game with  my family, and then also coming to a day of research with me at HSS. So Alessio is also a very prolific researcher, very early in his faculty career, and Alessio  will be talking about Weight-Bearing CT, how far have we come in terms of research. Third one is Matt Conte. Matt is a faculty at HSS.  We have been interacting for a long time, I think since I was a fellow at HSS. Matt just started his practice back at HSS, and here's a picture of him in Iowa visiting  and having some fun in the Capitol. Matt, even though just started his practice, we all know him, very prolific researcher  as well, and he's going to be talking about Weight-Bearing CT, tips to incorporate into your practice and your research.  Last but not least is Nassimi Mansour from Brazil, now in Iowa City. Nassimi was a practicing surgeon in Brazil. He came to do research with me.  It's been three years that he's been here in Iowa. He's actually the first day that we met here in Iowa City.  You can see that he was a thin guy and in shape, and that's why the reason why he's not like that anymore. He jumped into the Iowa sweet corn, and that was not very good for him.  So Nassimi, like I said, already a faculty in Brazil, so he's a very prolific researcher as well, and he's going to be closing saying Weight-Bearing CT, where are we going?  So what does the future has to us?  That's all I have, so we're going to go. Francois Alins is not with us in person, but he recorded his presentation, so Alin is  going to show his presentation, and please send your questions through the chat or the question and answer box.  If it is specifically for the speakers, we ask that you send the questions right after the talk so we can try to address them, and in the end, we're going to have a discussion  of more, I would say, broad topics if we have the questions for it, so please send the questions in the question and answer session.  So Alina, please take the lead, and let's start with Francois' talk.  City Society. So history we've always tried to find our way around and as surgeons in the foot  and ankle our job is to find our way around the foot and ankle. So if you look at let's try and  make a parallel between the history of finding our way around on the globe and finding our way around  in the foot and ankle. So we start by looking at the stars and then we invent some nice maps but  not too detailed and then some detailed maps and then satellite navigation and that's kind of a  chasm. And then the satellite navigation system brings you back information from the users,  it feeds you back, it increases, it improves you as a diagnostician. So if you look at this  arrow from star navigation to ways you can make a sort of parallel with what we do in finding our  way in the foot and ankle. So first we have clinical examination, we basically just look with our eyes  and then we have a tool so we have a roadmap and then we have an x-ray in front of that.  Now look at where the dentists are today, they have satellite navigation in the jaw feeding them information which allows them to do patient specific planning and that looks great.  In orthopedics where we are today is a little bit different, we have 2D x-rays and they're weight-bearing but they're 2D and we have 3D CT but it's not weight-bearing.  And then cone beam comes into the picture and then you have new measurements like three-dimensional  biometrics which help you find your way around better, which are better adapted to the new  environment. So we're looking towards this very near future, this present where we also have  patient specific planning, patient specific implants and we can now be as good as dental  surgeons, oral surgeons, max vac surgeons with our patients because we've got the same technology,  cone beam. So the chasm is really when cone beam comes into the picture because we've got 3D  weight-bearing. Now new technology also rises because there are some needs and we have the  need to evolve from these 2D pictures which are distorted. So here is just a small example but we see this every day, I'm not even talking about super imposition of bones but just  distortion of angles. There is one indication in which we all think maybe that an x-ray is  sufficient, dorsal plantar x-ray, but if you look at this case, we saw this patient in spring  and she had a close to 18 degrees intermetatarsal angle and she comes back four months later  because she didn't want to be operated on before the summer. She's now ready for the surgery and  the angle has come back to 14 degrees, so obviously it hasn't come back but it was the  picture that was distorted in the first place. There are also some pitfalls with MDCT, the radiation  dose is much higher and it's not weight-bearing. So of course you can simulate weight-bearing  but it's not the same thing and your patient still gets an extra dose of x-ray which he doesn't need.  You can also inject a cone beam CT to get an arthrogram. Obviously you don't need it as much  because thanks to the weight-bearing you can see those nice images of impingement here which show  you that you are stage four of arthritis in this tibial-talar joint. William Conrad Grungen in  1895 said I have discovered something interesting but I don't know whether my observations are  correct. So it was somehow correct to say this because there was distortion. Of course I'm just  joking here, this technology revolutionized medicine for over a century but now it's time  to turn the page around and to move to something newer. We need in order to do that to make it  available to everybody and it's the uses that drive the technology in terms of volume and then  the prices go down. It's been like that throughout human history for all kinds of technologies.  So this worked in the years 2000 for flat panel detectors which allowed the price of dental cone  beams to be driven down. Dental cone beam was invented in 1996. It was published by Mozo,  an Italian team I think based in Bologna and here is the very first picture they published of a  human skull and here are those devices which we all know from our dental offices.  So the dentist came from this panoramic to this beautiful 3D image of a patient-specific  implant with surgical planning included. In terms of technology, what is weight-bearing CT? Well  I want you to remember one thing in this talk. Cone beam comes in place of radiographs. It does  not replace CT scan, it replaces radiographs. So that's where it takes all its importance  because technologically it's very much closer to an x-ray. It's a source, a beam source with a conical  beam going through the object and projecting onto a flat panel detector and the whole thing  rotates. So it's a bit like taking an AP and a lateral and taking all the APs and laterals and  stacking them up together. So it's much closer to an x-ray. This is the result. It's called a  sinogram. So you can imagine something rotating around the object and producing this image.  Then you have to do a bit of maths to, from the sinogram, go back to the original image. So  basically just remember Fourier and Radon and these guys tell you for Fourier how to decompose  a signal which has many frequencies into the individual signals of a single frequency. And  Radon allows you to back project the sinogram into the original coordinates of the original  coordinates of the original picture. Hounsfield, Sir Hounsfield of course, British Nobel Prize,  described how to measure the intensity of the voxels which corresponds to bone density. And I think we are only scratching the surface in terms of what we can do with this.  The great advantage is that with weight-bearing CT you can scan your patient and you can turn  the foot around after you've done the x-rays. With x-rays everything's moving around the object  that's being shot and the object is also moving around and it's very difficult if you don't have  the right x-ray. You have to shoot an oblique view and another oblique view and it takes forever and  patient gets x-ray radiation. So reproducibility of the setup is very important. Also the settings  are being checked every couple of months by the industry with phantoms. So they check that the  distances are right, the density is right, and it's like checking intra-test reproducibility  very accurately and very often. The dose corresponds to 1.5 standard 6 view setups. So if you add oblique views or sesamoids it's basically the same thing. Just remember it's  lower than daily background dose in the U.S. and it's equivalent to what you would do in terms of  x-ray. So again it's much closer to x-ray than a CT. It's a 3D x-ray. This is what it looks like  in terms of history. We put it into our office. It's very small, very convenient, and we concentrated  on the marginal gains that we had in terms of acquisition time, freeing up traditional MDCT  slots, consultation slots, and for the patient means less time spent in the radiography department,  less appointments. But now we see that this is not the main thing. The main thing is improvement in  patient workflow. Basically you have your diagnosis now. Weight-bearing CT takes under a minute to  shoot and under five minutes to get the result, instead of weeks and sometimes months to get a CT  to finally get a diagnosis. However we have to learn this new environment. It's a 3D environment.  We're not used to it. We've been trained on x-rays, so we have to learn. And we have to  find the right tools because the angles are not fit in a 3D environment. So we must think a lot  because sometimes we are lost in this new digital environment with our old tools. Publications have  increased exponentially in terms of weight-bearing CT. The focus has mainly been on pest-planovalgus or PCFD, first-ray rotation, first-ray pathology, and the syndesmosis. But it's  like it was the same thing for standard radiography because it's just  where we need weight-bearing and where we are stuck. First-ray rotation is no way to see it than weight-bearing CT and also the syndesmosis, the syndesmotic pathology.  So here are all the publications which you all know by heart. And to finish, I would just  say everything's in 3D now. VR is in 3D. Even shaving is in 3D. Printing is in 3D. So I don't  know why it's not possible that we are going back to two-dimensional x-rays. So we need to turn the page. Thank you very much.  Excellent. So guys, this was a great introduction. So please remember to send your questions  in the question and answer box, and we're going to address them. I don't see any questions to date.  So we're going to go for the second talk. And again, I'm thanking Alessio for being here at three in the morning in Italy. Alessio, please, you can start.  You're muted. You're muted, Alessio.  Hello. Good evening for you. Good morning for me. Can you see my screen?  Yes.  Okay. So hi, everybody. It's a pleasure. Thanks for the opportunity to be here. My small task  is just to summarize how far we've come with this new technology. Let me see if I can go farther.  Yeah. Okay. These are my disclosures. So this could be there. And among the societies, I just underline to be a new board member of the International Weight-Bearing CT Society. So  what I've tried to do is essentially to build up a very short timeline. I'd like to bring you  with me in a sort of traveling time. If you just digit weight-bearing CT in foot and ankle,  it was the beginning of March, you will find approximately 260 results. And as you can see on the left, the graph says that every year there is a progressive increase of the number  of publications. So that's a sort of stairs. 2013, it was not the true beginning. It's just  when the first publications started to appear. On the left, you see probably the first review  on a radiology journal. On the right, someone talking about high-lux values and weight-bearing CT, and it was 2013. Let me just underline something now, and after it will be quicker  to bear this in mind, that if you take, for example, this paper that is often mentioned  in the references of papers like a weight-bearing CT study, and you look into that, it was a very  good study on clinical lateral ankle instability from Canada. You will see the description of the  methods that actually feet were assessed in a normal CT just resting against a foot plate, as you can read here. So it was not really weight-bearing. And that's something that can  happen quite frequently. So just pay attention to this when you read the paper. In 2014,  we started having interesting papers. This one from Professor Richter with a sort of comparison  between weight-bearing CT and radiographs and CT. Of course, I don't have the time to go into detail  of everything. It's just to give you a sort of quick look and probably to stimulate also some  of the audience to look into that. And of course, there were some differences. Soon after, someone  started looking at hind foot and subterior joint. Of course, this was, I mean, worldwide recognized as a difficult area to study on 2D radiographs, because as you know, subterior  joint is quite small and you can't really assess that just on bidimensional imaging.  And again, another study. Here, you can see hind foot alignment and  deep posterior dysfunction. And even here, if you open the study, you see this image. So it was a  normal CT. It was not really weight-bearing. 2015, other interesting studies, even more interesting,  hind foot alignment, so subterior joint and novel measurements described by our friend Arnie Burson. In 2016, there is not that much. I just wanted to bring up this study about  Mueller-Weiss syndrome. It's quite easy to understand how you can assess much better  the navicular bone on a CT rather than radiograph. It's quite intuitive. I don't have to describe  this more than that. In 2017, we have 19 studies. So numbers start to become something even more  important. In these studies, the angles in a cohort of Alux frigidus was a study just to  assess the reliability. That's something that has happened quite frequently in the literature,  even after that. And of course, it was just a way to test probably this new imaging for common  pathologists. And another study by Professor Richter, what he tried to do. Here, you read 2018,  but actually, it was first published in 2017. That's why it's in this light. And this applies  to a few studies in this presentation. Anyway, what he did, he put a customized pedigraphy sensor  into a weight-bearing machine. So it was an attempt to correlate the shape and the function  that is quite important in our field, as you know. A paper from Francois Linz, who was just presented before me, who introduced these new measurements. So apart from testing old  measurements, weight-bearing CT has also allowed us to introduce some new things. And that's the  first thing, is the foot and ankle offset. That's the first time that a volume is considered,  rather than a plane. So that's quite easy. It seems more difficult on images, but actually, it's just the position of the ankle as compared to the classical CAPNG tripod,  that is the foot on the ground with the weight-bearing points on the ground.  And more papers, 2017, always on subtalar joints. And someone also started looking at the ankle  with the rotation of the talus. That, of course, is much more easy to assess. And that's the last  study I'm mentioning about, again, here, weight-bearing computer tomography in the title.  But actually, that's what happened in the paper. And let me explain why. I mean, why I'm not  against this, just that there are essentially at least two reasons why that doesn't work. Probably,  first is the muscle contraction that, of course, is lacking here. And second thing is that you  cannot really control the amount of loading. And that's been amazingly described in that  landmark paper. That's the first important review. Also, Cesar mentioned that. And Francois as well.  So that's not the case. That's a must read. And it really clarifies pros and cons of cone beam CT  in foot and ankle. And it was from our beloved Alexei. In 2018, other reviews on the topic,  let me just underline on the left, something from Brazil on the left, European foot and ankle  orthopedic society. So it's something, it was something spreading around the world. And a lot on syndesmosis, actually syndesmosis is a difficult beast for us to be diagnosed,  to be treated. And mirroring that you see on the right part of the slide was already there. It's just that it was not on weight bearing imaging. So it was not probably so reliable  because the true position of the fibula and the tibia at the incisora did not just correspond to  the true version to the reality if you want. And as mentioned before, flat foot is a huge area of interest for weight bearing CT for a very simple reason. If you have just a small  clinical experience, you have seen a flat foot, you will remember the huge difference between a  foot just sitting and a foot standing because it changes almost everything. And let me just  underline this paper on the JBJS here on the right, where it was quite simple, but very important  study where the differences between standing and not standing were demonstrated. In 2019, other studies, not just syndesmosis, also chronical lateral ankle instability and  total ankle replacement with all the rotation of components, halux valgus with all the stories about pronation of the metatarsal rather than pronation of the first ray, etc. And  capovirus, of course, that's another complex three-dimensional problem. Of course, we need  proofs. It's not just about I like it and it seems better. So that's an important study always from  Professor Richter about cost effectiveness. You can have a look at that. In essence, it just  demonstrates comparing weight-bearing with X-ray and weight-bearing CT with X-ray and CT, that there is what we imagined. So there is a reduction in the radiation dose, an important  massive reduction in the time, and also an increased financial profit for the hospital.  Another new marker, again, JBJS, and that's the middle facet that was not just possible to see  on previous imaging. The incongruency of this facet and subluxation have been proven as markers  of peritoneal subluxation and, of course, flat foot. 2020-2021, I've coupled them just because  of some things in common. For example, these studies on distance mapping. What is distance mapping? It's just a different way to look at  joints. That's it. It's an objective way to assess what we generally do with the Kelgren-Lawrence  scale and radiographs, etc. And it can allow us to give numbers, so to quantify what happens in  the joint, and also to express this with fancy color-coded maps in order to make the message clearer. And again, reviews, of course, and further knowledge on progressive collapsing  foot deformity. Also, there is some space for weight-bearing CT in the consensus for the new nomenclature of the old flat foot that now is PCFD. I mentioned calvarous foot. There  is a number of studies growing in this area. Why? Because, of course, it's three-dimensional, it's multi-planar, there are problems with bones and problems with the joints,  and research is going on in this field as well. And also at the ankle. I mean, the number of  studies about the ankle is growing up from basic osteoarthritis assessment to rotational alignment  of ankle arthroglossity, and even more, assessing the value of weight-bearing CT in PSI that is seen  as the future for many of us. Forefoot is probably the most common thing in our clinics, and of  course, weight-bearing CT has been applied to Alex Valgus. Many questions, some replies are  already there, some others are coming, like the role of metatarsus primus elevatus, or the  importance of DMAA, or the role of the crista in the sesamoid position, etc. And again, still seeing  dysmosis in the same years, and also something on the list, Frank, we talk about ligamentous  injuries that are always very small in terms of anatomical region, and very difficult to assess  in a non-weight-bearing and non-tomographic environment. And also someone is starting to  look a bit upper than that, so that's a study I had the pleasure to take part in, and we used  just radiographs of the lower limb, because at that time there was not available weight-bearing  CT for lower limbs, but now the situation is different, and we just probably created these  groups with different morphologies, Valgus dominance, inverse combination, Valgus dominance.  That's not the topic, the topic is just the possibility of doing that. Most of the measurements  have been done until the last years just by hand. Many of us have done this, spending hours  running measurements, but industries have allowed us also to do that in a quicker way, so there is  this semi-automated and automatic measurements that have come up and are being tested in studies.  They look beautiful, but of course we need studies and that's what's happening, so  there is a massive reduction in time, that's obvious, and there are validating studies in course. And last but not least, 2022. I didn't include 2023 because we are just in April.  Some more studies, let me just underline. This one in the pediatric population, it was the first  one, it was quite obvious to get there. A big role of weight-bearing CT for fracture, starvation, and wrist flank injuries, and of course, regardless of the weight of the child,  there is a significant reduction in radiation dose that's important for every one of us, but especially for children. And that's a very useful graph that I borrowed from this  recent study of skeletal radiology. It just summarizes more or less what I've tried to explain in this presentation as well. There is a big number of studies, of course,  because it started from the foot, but there is a development for other areas as well,  with the knee, with diabetes, with osteomyelitis, and etc. So yeah, we would have, we would need  probably two days more to discuss all these studies, but time is running up, so let me just conclude that's obviously not a systematic review. I apologize if I have missed something  of someone important. Of course, as you have seen, the greater areas of interest are 3D  deformities, but actually all the foot and ankle deformities have some space in the weight-bearing  CT imaging. We have new replies to a question, probably also we have new questions. There is  a number of studies which has assessed the reliability, because it was a sort of preliminary  testing for known measurements, and as I showed you, there is also new measurements coming up that were not just possible before before weight-bearing CT. Probably in the future,  what we will see is a correlation with suprasegmentary axis, because now we can, because now we have the machines to do that, and of course that's what we need, some more  studies on the correlation with clinical outcomes. Thank you very much, and regards from South of  Italy. Excellent, Alessio. Thank you so much for covering that much content in a short period of  time. We appreciate you being here with us. So, Matt, you can, we're gonna have Matt Conti to  talk about. He just started his practice, so how long ago? A couple months, Matt, now? Yeah,  I'm like, I'm four or five months in the practice, but I have ordered a bunch of weight-bearing CT  scans, so I'm excited to talk to everyone about it. Yeah, he's gonna share the magic of how to  incorporate in his practice, so let's do it. All right, well, thanks for having me, and thanks for  thinking of me. Honored to be with such a great group tonight, and my disclosures are similar to  everyone else. I've done a little bit of consulting work for CurveBeam, which creates, which has one  of the weight-bearing CT scanners, so I'm going to talk about the advantages of putting a weight-  bearing CT scanner in your office, and then how I've been using it to evaluate foot and ankle  deformity, and then I have some case examples and examples of clinical indications, and then  briefly, we'll talk about weight-bearing CT scans and research, although we've touched a little bit  about on that already. So in the office, unlike conventional CT scanners, weight-bearing CT  scanners can be incorporated into the outpatient office setting, and so I've seen numerous private  practices who have put weight-bearing CT scanners in their clinic space, so that can help improve  workflow in your clinic. You can avoid sending patients from the clinic to the hospital or radiology. Our weight-bearing CT scanner is just downstairs in our clinic, and they can be  performed standing, but the other thing to consider is that weight-bearing CT scans can be performed  seated too, so if you have a ankle fracture and you want to know whether they have a posterior  malleolar fracture, or you want to better assess maybe the syndesmosis, or you want to look for,  or you want to assess like a pilon fracture, these all don't have to be performed necessarily  weight-bearing. If you have the weight-bearing CT scanner in your office, you can perform them  seated, and so common uses of it are for diagnosis and evaluation of deformity, post-operative  evaluation of arthritis, and if you're looking for a union following in arthritis, the weight-bearing  CT scanner can be a quick and easy way to look at healing across the arthritis site, and then also  evaluate a fracture like I just, like I just talked about, even in a non-weight-bearing way.  And I'm just going to spend most of the time talking about evaluation and diagnosis of deformity. So common indications for deformity evaluation in my practice are progressive  collapsing foot deformity. I think we've talked a lot about it already. I have a case example  on progressive collapsing foot deformity. For me, it is very difficult to truly evaluate the  hind foot alignment, and to evaluate the subtalar joint, and to look for impingement unless I'm  getting weight-bearing CT scan imaging. And so we'll talk a little bit about the advantages of  weight-bearing CT scan even over perhaps an MRI. Subtle Liz Frank injuries are things that plagued  me. When I started, I seemed to have four or five patients that came in with these really  subtle Liz Frank injuries, and I wasn't sure what to do with them. In the first few, I was getting  MRIs on, but then you see that the Liz Frank ligament is injured. But what does that convey  about instability? And so getting a weight-bearing three-dimensional image can really help us  evaluate whether there's instability. In Charcot, it's really, it's very helpful to see where the  instability is, especially in midfoot Charcot. In sinusmodic injuries, we talked about this already,  looking at sinusmodic widening. In ankle arthritis, evaluating deformity of the hind foot.  And in midfoot arthritis, looking at joint space narrowing, and it can often be difficult in the  tarsometatarsal joints to identify exactly where the midfoot arthritis is and where it's most severe. And so getting three-dimensional imaging in a weight-bearing fashion can be  really helpful for that. We talked about already cavovarous deformities, and then even in Hallux  valgus. And so I think about what I'm using three-dimensional imaging for with broad categories,  and three-dimensional imaging can really, three-dimensional weight-bearing imaging can really change our management of disease. So for example, can evaluate bony impingement,  like subfibular, subtalar impingement, and progressive collapsing foot deformity. It can help us better understand instability, whether that's instability at the Liz Frank  interval, whether it's a sinusmodic instability, whether it's midfoot collapse, either midfoot arthritis in Charcot. Three-dimensional imaging can help understand not only  where there are arthritic changes, but also where there's actual instability when people are standing. It can help consistently assess alignment of patients. So  depending on where you are, trying to get a hind foot alignment view can result in patients being positioned differently, which can lead to differences in the tibiotelar calcaneal  axis. And so obtaining a weight-bearing CT scan can really help us consistently evaluate alignment  better, because like we already talked about, the weight-bearing CT scan can be obtained in any  direction, and then you can, or the foot can be placed in any direction, and you can reformat the  images, so you can really consistently assess alignment. Understand rotational changes of bone,  such as first metatarsal excess morning position and hallux valgus, and then also determine arthritic  changes and joint space narrowing. So I just wanted to put together how some of the cases  that I'm seeing and how I'm using these in my practice. So obviously, progressive collapsing  foot deformity is one instance, and I'm very fortunate that here at HSS, I get very consistent  hind foot alignments, but not everywhere was not, and not all of my places actually at HSS am I  getting consistent hind foot alignments. But for the most part, I am. But if you're not, really assessing hind foot alignment can be rotationally dependent of where the foot is.  And then in addition, things that I found hard, I mean, we'll talk about some subfibular impingement, but also just for me, looking at the talonevicular joint, and we, you know,  we're taught, well, if it's over 50% on 40 or 50% uncover, then you need a lateral column lengthening. And as we move maybe away from lateral column lengthenings, are we really  assessing, how are we really assessing abduction at the talonevicular joint? And so I thought this  is one thing you can do with weight-bearing CT scans is you create a three-dimensional model.  And so you can, you can take a look at this foot and you can rotate it around  and you can better assess, I think using the weight-bearing imaging, what, where is the actual  talonevicular joint? What is, how much abduction is actually at the talonevicular joint? And so,  and so using weight-bearing CT scan imaging to really evaluate something that seems that,  that we've been doing on radiograph for the last 50 years is, is really, really helpful in my  practice. And then things that we talk about all the time. So whether there's, whether there's true  sinus tarsi impingement and weight-bearing CT scans make that very clear and whether there's  subfibular impingement and when there's true subfibular impingement, you know, that's changing  the management in my practice. And then also looking at middle facet subluxation and looking at the severity of subluxation at the taloid, at the talocalcaneal joint.  And then here's that subtle Liz Frank injury. And you look at this patient and,  and you think, well, you know, there's, is there really widening on the, on the left side?  And then we look and we see, and we, we can look at the weight-bearing CT scan and now we can  appreciate, well, there's a small fracture at the base of the second metatarsal. There is mild  There is mild widening on the, on the left side here. And, and you can see this is four, this is 4.8. It depends a little bit on where you measure this, but this was, this was one  slice that I thought was, was clearly demonstrated that the left side is more unstable than the, than the right side. And, and then I just took the measurement out here to show,  to show widening. And to me, this is a better way to diagnose instability within joints because,  you know, taking this patient to the operating room and say, well, we're going to abduct and  abduct your forefoot. And we're going to decide if there's, if we need to put a screw across it  before when we get to the OR is a lot different than, than knowing in advance that I'm probably,  that I probably will need to fix this. And this is probably going to be unstable when I get to  the operating room. And then here's a Charcot case that I had and just understanding where  is the talus when this patient is weight-bearing and what happened to the navicular and where is  the real instability within the midfoot. And so we can take weight-bearing CT scans and, and,  you know, and we can better evaluate what's happening with the talus. And we can realize that the navicular was, was up in her ankle joint and there was very little navicular left.  And then also what I realized when going through the weight-bearing CAT scan was that when I,  when I made my medial approach to this patient, I knew that this, the first thing I was going to  be looking out on the medial side was actually, this is actually navicular over here. So when I  made my medial approach and I found the navicular first and I took this out and then I was staring  at the tailor head. But when, when you get into the OR, you're in this case, everything is in the  wrong position, right? So really having a better sense of where things are in three dimensions on a weight-bearing CAT scan is, is incredibly helpful for Charcot.  And then looking at syndesmotic injuries and looking at instability with athletes. And here was a 21-year-old collegiate quarterback who presented with right ankle pain after being  tackled. And for six weeks, he really hadn't gotten better. And so we brought him to the  weight-bearing CT scan scanner and we put them in and we have them stand on the weight-bearing CT  scanner and we internally rotate the tibia, which is the same as externally rotating the foot.  And what we can see here is that when we make our measurements, you know, anteriorly, he's, he has six millimeters of displacement between the fibula and the tibia, whereas on the  asymptomatic side, he has 4.9 and then he has four millimeters more centrally and then 5.6 equally on the back. And so what we can see is that the fibula is externally rotating here  compared to the tibia. And then we can measure the syndesmotic area and take a look and see is  just, is in the weight-bearing position with stress applied, is there a significant difference  between the two areas? And I would say that we still don't know. We don't know what these measurements are, but with weight-bearing CT scan, at least we can get closer to diagnosing  these patients before taking them to the operating room and doing a diagnostic arthroscopy.  And then, and then in this ankle arthritis case that I had, we see erosion of the tailored dome  and very, it's very difficult to understand what's happening at the sub-tailored joint.  So then we can, so then on our weight-bearing CT scan, we can see, you know, I can take a look and  see where is his, where is his calcaneus and what's going on with his sub-tailored joint compared to his tibia or tailored joint in the weight-bearing position. And I, and you know,  and you know, my sense is based on the scan that once I, if I correct his tibia or tailored  valgus, then actually his heel will come around and I probably won't need to, to do a heel slide. But it just gives me, it gives me much more information. I feel much  more confident about what I'm going to do, what I'm going to do for this patient before I get,  before I get to the operating room. And it, you know, in this particular case, actually, I think I've probably planned to do a two-stage procedure because I think we need to address  this sub-tailored joint. And then finally, I just want to touch on weight-bearing CT scans and research and where we are. And we've had, Alessio did an amazing job presenting the  research over the past few years. And so progressive collapsing foot deformity and hallux valgus and syndesmotic injuries are really top of our mind, but cabovirus foot deformities  or any, or Charcot are all opportunities that are right for research. And so for progressive  collapsing foot deformity, Caesar's published extensively on middle facet subluxation or, or deformity correction in understanding flat foot. And I, and I would argue that  weight-bearing CT scan over the last 10 years has really advanced our understanding of flat foot or progressive collapsing foot deformity. And so has really inspired our,  us to change the name and to really reclassify how we, how we look at flat, how we look at progressive collapsing foot deformity. In hallux valgus, we've spent a long  time looking at rotational changes of the first metatarsal. And we know that these, that rotation of the first metatarsal is weight-bearing dependent. And so being able to put these  patients in a weight-bearing way and then look at their rotation is incredibly useful to understanding  hallux valgus. And we've, and we've published on looking at, on recurrence rates and patient  report outcomes following a correction of the pronation deformity. So we know what we're doing  and what we're seeing on weight-bearing CT scans is affecting our outcomes. And it's helping us  better understand diseases and maybe, and for the lab, you know, for a hundred years, people have  talked about hallux valgus in, in typically one plane on an AP radiograph. And then people maybe  looked at the sagittal plane and said, is there instability at the first metatarsal joint? But we now know that hallux valgus is a three-dimensional deformity and we can better  look at it and classify it and understand the disease. And based on that, we can better treat  patients. And so here's a patient that I, that I recently operated on and we, and we can look at  her first metatarsal rotation. And, and in fact, she really didn't have much rotational deformity of her first metatarsal.  She had significant subluxation of the sesamoids, but her rotation was not terrible. So I think that gives me an idea before going into the OR how much pronation correction  I'm planning to do when I get there. So I'm not, I'm not guessing interoperatively. And then finally, syndesmotic injuries, and these are also, these also have advanced our  understanding and potentially have helped us to better diagnose patients before we get to the operating room.  And so multiple groups have looked at differences between normal and abnormal syndesmotic measurements using weight-bearing CT scans.  So I think the future of weight-bearing CT is amazing. And the way I'm using my practice is that patients with multiple diseases are getting  weight-bearing CT scans, because I think we're all in, we're in a environment where I want more information and I want to better understand diseases.  And I think weight-bearing CT scan is really helping us to do that.  So thank you very much.  Outstanding, Matt. Very good. We do have a question from Erdy. Erdy, since we only have your question today, we're going to keep it, we're going to answer it live. Okay.  So if we can, for some reason, answer live, then we're going to type our answers. Each one of us will give you our opinion on it. So hang in there.  We're going to go for the last talk.  So Nassimi will close it by saying, what does the future potentially will bring to us?  Well, good evening, everyone. And thank you so much for the invitation. I'm very happy to be here with this great panel.  And I'm going to talk about where are we going with the weight-bearing CT. I'm sorry. I went a little bit.  And these are my disclosures for tonight, nothing really related to the presentation here.  I'm going to divide my presentation in three pillars, I would say. The first one, I'm going to talk about the advances with segmentation.  I'm going to discuss a little bit of the new tools that we are having with weight-bearing CT. And finally, the advances in the machinery that are coming for the past few years and  also for the future. So segmentation, as already stated by my colleagues here today, is nothing but taking the images  and building bone models. That can be done manually or automatically. They are both very reliable and they produce very good and high-quality images and very  good assessments in terms of measurements. And that can be used to assess relation between structures and also the interaction between these structures.  And that can be done in a simple way as a 2D environment to assess a matrix and also angular relation between these structures, but also can be used in a more advanced way  to produce 3D interaction between the bones or the structure that we are studying and develop what we call distance and coverage maps.  The 2D assessment was previously and was already pretty much established, as Alessio already  demonstrated and Capra, one of our co-workers here, was able to demonstrate that semi-automated  bone segmentation was able to produce measurements and values that were pretty much reliable and capable of distinguishing what was diseased and what was normal.  But for sure, when we try to understand the true, I would say, the true north of wave bearing CT, the 3D relation between bones, and the first paper was published by Deburn  and Caesar, where they took the peritelosubluxation concept and tried to demonstrate a difference  between patients with PCFD, with flat foot and controls, demonstrating how much coverage was changing and also the distance between bones was changing.  We took the same concept and also applied to other joints, such as the shoulder joint and also the ankle joint, and other authors did the same, such as the Utah Group recently  published a comparison between controls, flexible PCFD patients, and also rigid PCFD  patients demonstrated that coverage was increasing also when comparing flexible and rigid patients.  The COVID virus configuration was addressed by Francois and Alessio, Alessio talked a little bit about it, and lately we are seeing a lot of use of the 3D assessment in joints  or in conditions as discussed by Matt, that diagnosis is very difficult and is millimetric or very dependent on mild difference that can be clinically relevant.  So the MGH Group studied that and they used area and volume to distinguish between patients with injuries and with no injuries.  The Utah Group, Aaron, Dr. Saltzman, and Emil did the same in a cadaveric model, assessing  the relation between the fibula and the tibia and seeing how much that changed as the injury or the instability progressed over time.  And we are doing the same to study the difference between patients with symptomatic injuries  and as being very, very aggressive or mild, mild difference or very subtle chronic injury.  One of what we believe is going to be the main impact of the use of this three-dimensional assessment of the three-dimensional coverage and distance map is the fact that we can,  we will be able to apply that to treatment. So Cesar demonstrated that we can improve coverage and we can improve the relation between  bones that can be measured by distance and that can be translated in better clinical and in better patient reported outcomes.  As the software is developed and as the software is fed with clinical data and also research data that can be used in a very near future that can be used to plan our surgeries or  to plan our treatment in that example is a PCFD patient, but that for sure will be used for us to plan a lot of surgeries, can be various surgeries, total ankle replacement,  so on and so forth.  I want to briefly touch on what we are expecting, what we are having in terms of new technology or new tools that are coming from Marie Barron CT.  So Francois already stated the importance or also the use of Hansard units. So Hansard units are nothing but a quantitative way of measuring bone density and that, so  as the x-ray combing is attenuated or absorbed by a tissue that can be translated in a measured Hansard unit.  So air, for example, is minus 1,000 Hansard units, water is zero Hansard units and bone would be plus 1,000 bone units and metal will be plus 3,000 Hansard units.  That can be a surrogate for us to understand or to read bone density and we use this concept to address or to assess joint space.  For example, we should take a line that will read the Hansard units from, for example,  the distal tibia to the proximal talus, we will be having a plateau of Hansard units that will be corresponding to the cancerous bones.  We will have a peak of Hansard units that will correspond to the subchondral bone, then a valley that will be the joint and then another peak in another plateau,  the subchondral and the cancerous bones. So if we take, I'm sorry, if we take a normal ankle, for example, and we trace four different  lines, we'll be seeing the same pattern going on, the same peak and valley. But if we do that for arthritis or for arthritic joint, we will be seeing a loss in this valley  going on to different aspects of the joint. And if we lose completely the joint, the value will be completely lost.  And that will change the way we understand ankle arthritis for sure, not only the way we assess it, but also the way we discuss with patients  and also how much prognosis we can give to a patient in terms of joint space-wide and also how much our joint space or joint sparing procedure is actually improving  joint space-wide and probably improving patient reported outcomes.  We use the same technology to assess bone healing. In that study, we compared two different implants, but the main outcome was to be able to see  the capability of the Hansel and Gretel's algorithm in identifying bone healing to the osteotomy site.  And we were able to find that that was very reliable and corresponded with the bone healing stage.  And that can be used in the future, not only to better assess, but also objectively assess bone healing and also fusions, for example.  The beautiful minds of Alessio and Francois, they use the same concept to study how much  stress and load can modify the bone trabecular disposition. And of course, that can be translated as a Hansfeld unit algorithm.  And that not only be the key to understand how load is propagated to a better alignment or worse alignment, but how much we can change these Hansfeld units and bone density  distribution with our procedures.  And lastly, I'm going to talk briefly about how the equipment or how the development of the new machineries are impacting our lives, our clinical or clinically our patients.  So we are all familiar with the new machines that can assess not only the hip, the knee, and the ankle, they are being able not only to give us a better perspective of what's  going on specifically in that joint, but also as Alessio showed before, is allowing us to see how the relation between the foot and ankle alignment is going on with a more proximal  alignment. The literature is growing in that field. So we are seeing more and more papers about knee and some on hip, basically focused on  knee arthritis and patellofemoral joint contact.  This is growing in the last few years, and these researchers are using some of the concepts  that were introduced in the foot and ankle studies to better address or to better understand the relation between the distal femur and the proximal tibia.  And we received the news from the two companies that are working with weight-bearing CT that  in the future days, in the next few months, we will be having what will be the first full body or at least at the base of the cranial weight-bearing CTs that will definitely impact  completely the orthopedic practice, because it will only impact, as Francoise was saying, the time and cost to obtain these images.  Some of the patients in orthopedic practice, they need to have a full body assessment through  x-rays, and these machines will for sure impact not only time cost, but also the amount of  radiation that our patients are getting, and also allow us to fully integrate the foot and ankle with the proximal joints, not only the lower limbs.  So in conclusion, we are going for a broader acceptance and broader use of segmentation, not only for diagnosis, but also for prognosis and surgical planning.  The use of weight-bearing CT technology, these new tools that we briefly discussed,  are allowing us not only to assess local bone quality, but will for sure change the way we see  ankle arthritis, the way we assess bone healing infusions, and also the way alignment is impacting the bone trabecular and the bone density distribution.  And the new machines, you for sure, as I just said, impact on time, cost, the radiation, exposure to our patients, and also allow us to integrate foot and ankle with the rest of the  body. Thank you very much. I want to acknowledge my colleagues from the lab, especially Cesar and Kepper, good friends, and great co-workers. Thank you.  Outstanding, Nassimi.  Thank you so much. Those were great lectures.  We do have some questions here. So let's do Erty's first. So Erty, thanks for being here with us. Erty is asking, I would like to thank all faculties for the great talks.  What is the most important development in weight-bearing CT that changes your surgical decision making in progressive collapsing foot deformity?  So I'll leave mine for last. Matt, you're the first one. So let's try to keep it brief so we can answer the other questions.  And I do have a question for you guys as well before we finish.  I would say subfibular impingement, for me, is really best assessed on weight-bearing CT scan. And when I start to see pretty significant subfibular impingement, I'm thinking about  fusing this. I'm almost always going to fuse the subtalar joint. So to me, subfibular impingement is really important on weight-bearing CT scans.  Matt, can you explain that a little bit better so people that are not really used to looking to subfibular impingement, why subfibular impingement is a potential recommendation  of subtalar joint fusion for you? Can you expand a little bit?  Yeah, I mean, I think when the calcaneus, so subfibular impingement occurs when the fibula typically contacts the calcaneus.  When the calcaneus is sliding out from underneath your talus, there's pretty significant instability at the subtalar joint. And so to me, that's an indication for subtalar fusion.  Excellent.  Alessio, would you like to comment for you? Yeah, I want to say something about it. Yeah, yeah, exactly. I totally agree with Matt.  And I'm sure I agree with you as well, because you will be thinking the same about the impingement story, because it's the real thing that we could not see before.  But I would couple something to this. I would associate something that is the concept of the joint space, because essentially we  are always split between joint preserving or arthrodesis, okay, when we treat these patients. And there are cases where you see a joint that is not that bad that actually completely  collapses on weight-bearing images. While there are others that probably are not fantastic, but they are sort of a bit more  stable if you want. So I cannot say that's an evidence-based thing, but I think that guides me a bit more towards the decision, do I want to risk an osteotomy?  Can I rebalance this foot and keep the joint? That's something I like to do. I like to do every time. Or do I need to fuse it?  So I think that's, I don't have a clear reply at the moment, but I think that's the areas in which I feel most influenced by the new technology.  Nassimi.  I want to state, we didn't discuss this a lot, but I think it's a very simple but genius way of assessing deformity.  There was, the concept comes from Francois, his foot and ankle offset.  Of course, you need software to measure, but it's a very simple way of measuring. And it's incredible.  And I can tell from experience, because I measure a lot of foot and ankle offsets, it's very reliable and it states a lot what is the, I would say, the overall alignment of  the patient. And it's very related with the way the patient is standing, of recurrence rates, of if you need to do additional procedures in any way.  It can be a total ankle or a flat foot, as we were saying. I think I want to highlight the importance and the use of foot and ankle offsets.  Just a final, I agree with all the comments.  Couldn't agree more with what was said here. For me, Erdi, is one of the things we've been trying to put data on it is answering the  question of like, do I need surgery for flat foot? Is my flat foot going to get worse, right?  And it's, this has been tried, attempt several times in the literature, way past, before like the real weight-bearing CTs were available and people were trying to simulate weight  bearing. But I really think that we're going into, I think Matt mentioned about his, Alessio as well, we're going into the details. We're going into accuracy.  And I dream about having what I call in my lectures, the magic numbers or the threshold numbers that we have for other specialties.  Like when we have HbA1c, for example, more than 6.5, that's diabetes.  If it's smaller than that, less than that, then it's not diabetes, right? Why can't we have these type of numbers to guide us, to offer treatment, right?  So if we could have these magic numbers, and then for example, medial facet subluxation can be one number, it's in the literature. The amount of inclination of your subpolar joint  posterior facet is also in the literature from HSS showing if you have a more inclined, more than 18 degrees of the posterior facet,  it puts you in risk of developing progressive collapse and foot deformity. Another one that I want to highlight, it was mentioned here, but not specifically,  I've been more in love with sinus tarsal impingement. We know the subpolar impingement, like Matt mentioned, is a big deal in terms of disconnection  between the talus and the calcaneus, and at that point you should consider  a subtalar joint fusion, but sinus tarsal impingement in my mind is much more important than we think. I think it's, once you start hitting your sinus tarsal,  and there's no data to support this, but it's my passion, my current passion. Once you start having sinus tarsal impingement,  I think the center of rotation of the subtalar joint that was beautifully demonstrated to be on the middle facet by Andy Goldberg and his group,  once you start hitting on the lateral side, your center of rotation is now on the lateral side, and then as you would expect, anything that is far away from the center of rotation  will suffer a lot of stress, and everything that is medial,  now with the center of rotation on the lateral side, we will start going to a lot of stress, so I think sinus tarsal impingement is a big red flag  for when your soft tissues on the medial side will start degenerating very fast. So trying to find these signs, or these red flags, or these magic numbers to be able to answer  the question for patients, for example, with PCFD, I think that's where we're going, that's where we should be going, okay? So hopefully,  or we gave a little bit of more questions for you. That takes us into the next question here, I think it's an important one. It's an anonymous attendee,  so that's something very secret. We never will know who that person is, but can each of the panelists elaborate on the software to use for the analysis?  So let's start different now. Alessio, do you want to start with that one? Yeah, I generally use BoneLogic, that you will all be knowing very well  for the distance mapping and segmentation, but I also have Automatrix, that is from CurveMe, so I use both of them, and it depends on the moment, it depends on what I need more,  but both of them are very useful to me.  Nassimi? I use CubeView and BoneLogic from Deezer.  Matt?  At the risk of being kind of like a dinosaur, I just use our normal PAC system and look through the imaging, and I find that to be sufficient for treating most of my patients,  and then for research purposes, we use CubeView and BoneLogic by Deezer as well.  We use them for different reasons. Deezer, the BoneLogic software, does a really good job of segmentation, but we have talked a lot about foot and ankle offset tonight,  and that's a specific measurement that you have to do through CubeView, so I know a lot of our disclosures have been through CurveBeam, and so just so everyone knows  that the foot and ankle offset is a specific measurement developed with the TALIS tool in CubeView, which is a software that's put out by CurveBeam.  Excellent, yeah, so people understand, people that don't have experience with WaveRCT, so Matt touched on a very important fact, that is, you can see all those images in PACs,  so you would be able to see your axial view, your coronal view, and your sagittal view. Some of the PACs versions allows you to do 3D reconstructions as well,  so you could use the regular PACs viewer that you have. Then we have the machines that are available in the market,  they usually come with their own software for visualization. We currently have two companies selling hardwares in the United States. With one of them, you can use the CubeView,  that is a specific software for viewing 3D WaveRCT images, and you also have the Deseor as an analysis for the other WaveRCT company.  The Deseor software, and now the CurveBeam as well, they both allow you to do semi-automatic segmentations. So before, you would have to segment all the bones  in the lab, so it would take a long time, it could take up to four hours for segmenting all the foot bones of one single foot,  and these companies were able to come up with algorithms where it could take you two, three minutes for you to segment all the bones in the best scenario  if you have a good computer. So that makes segmentation and bone assessment in terms of axes and distance mappings and coverage maps like we discussed here much quicker,  so you could potentially use in a clinical setting. So that's the important thing is that all these tools needs to be quick and easy,  otherwise we can't really do that other than for research. And then just to finalize, if you really wanna do research, you might need more softwares.  So I would just show, specify some names here,  but there's several options, but you have Slic3r, you have Mimix, you have Geomagic, those are three most commonly used for you to do more fine tuning of the segmentations  and doing more hardcore measurements and shape modeling and all these things that for a clinical scenario, that is a little bit too much because that takes a long time.  So that's more for research, for specific details that you wanna get out of the bones, but those are the names and we're happy to provide for this anonymous source.  We're happy to provide the names,  just reach out to us  and maybe we should all put our emails in the chat box before we're done.  We have a third question here. When looking at high values of foot and ankle set, how do we decide on doing a very big MDCO, more than 10 millimeters or maybe a lateral column  or doing more traditional MDCO of eight millimeters in a slight lateral column? That's Rodrigo.  So that will probably be, like I think the question is how to decide when to do more MDCO, how to decide when to do more lateral column lymphony.  I'll start with Nassimi for that one. Oh, sorry, Alessio has raised his hand. Yeah, yeah, I wanted to go, you know, I'm in love with foot and ankle offset, so that's why.  So I said, that's a very good question, but that's just to share my opinion with all of you. I don't think we have an answer for that because the foot and ankle offset,  it's a very good way to understand  where you are starting from and what you want to get. But at the moment, it doesn't allow you to sub-analyze the hind foot, the mid foot,  because it just allows the overall alignment as Nassimi was saying just before. So I don't think that just based on the numerical value  for the ankle offset, you can make this decision. In my hands, this decision will depend on other factors like the MDCO is a shift of course,  the lateral lymphony will depend a bit more on the talon-avicular hand coverage. You may have a very big hand coverage that is not related to a small or big foot and ankle offset.  So I don't know if it does make sense. And for the cotton or lapicotton, there you are talking about mid foot. So the decision of the mid foot will be entirely different.  I would not say, oh, I'm going to go for a cotton because the foot and ankle offset is 10. Okay, I'm going to say it's 10. I have to do a massive correction  because he is really collapsing a lot, but I do the job. And after I remeasure the foot and ankle offset to understand what I have done.  But in my hands, it's not the numerical value that guides what I do. It's more the shape. It's a morphological decision in my opinion.  We do have to ask Matt because Matt has several publications with x-rays demonstrating you change one thing, you get improvements in patient reported outcomes for flat foot.  So how did weight-bearing CT change your way of deciding that Matt and how are you doing now?  Well, I would just to answer the question, I agree with Alessio that you can't, I wouldn't base my entire reconstructive decision based on one angle, right?  Or one measurement, right? And so foot and ankle offset is one hind foot measurement that looks at where the foot is underneath the ankle. And I mean, that's the exciting and beauty  of progressive collapsing foot deformity  is that there's many decisions, there's many deformities within the foot that we have to correct. And each of them are individualized. So I don't know that foot and ankle,  like for me, I don't measure foot and ankle offset necessarily before I correct a flat foot because I don't know what it means. I know once I get everything right,  I know what it means postoperatively, but I don't know what it means in my decision-making. So I take each individual deformity and I try to correct them individually.  And so whether that's, you know, doing a lateral column lengthening or doing a hind foot slide, it's not based on just one measurement.  Assimi.  I agree. I think you can have like a subjective estimate if the foot and ankle offset is high as Alessio was saying.  We don't have this answer yet. I think we're gonna have in a near future,  not only using foot and ankle offset, but other measurements that can, based on, I would say, AI and based in clinical studies and cadaveric studies and research,  we're gonna have in the near future a better way of planning these osteotomies or these realignment procedures to better correct, not only the overall foot and ankle offset,  but also specific measurements of collapse.  I think if you have, for example,  post-op patient that you did, you think you did a great job and you measure the foot and ankle offset with three months and six months, the patient is still recovering,  but the foot and ankle offset is like seven, eight, nine. I will be worried about this patient having symptoms. Of course, this is very subjective. This is not, this is anecdotal,  but I'll be worried about my correction not lasting or at least not accomplishing good outcomes.  Well, we have to start going to a close. Alina is on, so you know that she's on to speed us up. And it's great Alina is here taking care of us. I just have to mention that  we found the secret. We found the anonymous because he texted me and it's Amgad Halim, so we know who he is.  Thanks for letting us know who the anonymous source was. Amgad, it was a great question.  I just want to say that, remember, it's all 3D. You change one position of the bones, the entire thing will change. So that question won't be answered that easy, Rodrigo.  That needs more studies.  And like I said, Matt did a great job with x-ray and showing you change this. You get improvements in patient-reported outcomes  like for cotton osteotomies, MDCO, so on and so forth. But it's more complicated than that. Matt didn't have the proper tools to do it before.  So he's going to do like an even better job than he already did to show us what we need to do to improve the patient-reported outcomes. Quick questions for us to finish, okay?  We can't take more than 20 seconds to answer that. It's going to be a different question for each one of you guys. I'll ask you, what are the patient  that you don't get a weight-bearing CT? Because I know you would get for pretty much every single patient. Don't come to me saying that you don't have a weight-bearing CT  because that's not going to be acceptable. But which patient you would not get a weight-bearing CT?  Sinobial cyst.  Sinobial cyst.  I was going to tell the truth. No, I'm saying just those patients where I don't need any information about the alignment. That is quite rare, to be honest,  because the alignment is in everything. But if you have like a dorsal cyst of tendons, I don't need a weight-bearing CT because I'm not worried about the alignment.  But apart from that- You might miss the mid-foot arthritis that is starting and created the cyst on that case, but that's fine. I'll forgive you for that one.  Thank you. Matt, Matt, you started your practice five months ago, and I'm sure you're having a lot of fight back from the insurances and peer-to-peers.  And I'm sure there's a lot of people at HSS wanting to cue you because you're ordering too much weight-bearing CTs and someone is having to do the peer-to-peer if it's not yourself.  So how are you dealing with that? Is that a real deal? What are the tricks for having less problems to get the weight-bearing CTs approved  to treat your patients?  Yeah, I haven't had any problems. So maybe it's because I have good people who have been here before me. I thought I might have...  The only patient I thought I might have a problem with is the Hallux Valgus patient. So I have a little smart phrase that just says, I need a weight-bearing CT scan  because it's the only way to evaluate alignment of the first metatarsal bone  and based on our previous data or studies that are out there, alignment leads to decreased recurrence rates and improved outcomes. So to me, I just cited some of the literature.  I know that that's also been helpful for Scott Ellis when for Hallux Valgus. So that's what we've been doing here. But for anything that's a big hind foot deformity,  I haven't, or Liz Frank, I haven't had any, I really haven't had any problems. So it's been, I wonder if it's just becoming more and more accepted.  And I did actually check, I checked to make sure that all of my weight-bearing CT scans were reimbursed and 100% of them have been. And they're being charged as CT scans or x-rays?  Yes. No, CT scans, yeah. Okay. Well, maybe you should share with all of us the smart phrases if they don't have any patient information or nothing like that, maybe it's a good idea.  Whoever wants smart phrases or justification for weight-bearing CTs,  please contact Matt Conti. And he put his email on the chat box here. The same- I only have it for bunions only, but I'm happy to send you mine for bunions  because that's the only one that I haven't had a, I've had a problem getting insurance approval. I'll tell my quick experience here. When I started here in Iowa,  I, all the PAs and all the people that were doing the peer-to-peers for my department, they hated me for a long time because there was a lot of peer-to-peers.  And then by using for standard of care, and the insurances, I believe they have my picture and they say, oh, that's the crazy Cesar from University of Iowa,  just get it approved or something like that. Because we now, or the reality is that it might be like Matt mentioned with more and more data. I think the insurances are understanding  that the indication for weight-bearing CT like Alessio and Francois mentioned are the same indications for x-ray. So the insurances are getting to understand  that better in the number of need for peer-to-peer or denials for weight-bearing CTs went crazy down. So I would say maybe we have one  or two peer-to-peers a month now for weight-bearing CTs. And that of course depends on where you are, depends on the insurance and the local situation that you guys are.  It just says probably Matt is spoiled. Maybe it might not be that way for other people. Nassimi, last question of the webinar. It would be, if you had to choose one thing  that you would carry with you from what you learned with weight-bearing CT for the near future, if you can choose one thing, what would that be?  Coverage mapping.  Coverage mapping for sure. And I think that of course I learned from you, but I think that's gonna change the way we assess, understand and discuss diseases, right?  Because we all know if we improve coverage, we improve interaction between bones, we are probably improving the way patients are walking or patients are moving.  And we're gonna see in the next, Matt is doing that and we are trying to do this. We're gonna see the effect of improving coverage  in patient-reported outcomes and clinical results for sure.  Yeah, you learned from me, I learned from Alessio. I don't know from whom Alessio learned, so we will keep going. Actually, we all learned from Bruce St. Georges, right?  Because Dr. St. Georges published on coverage maps back in 1999 in JBJS. So we all learned from someone else. So that's the beauty of what we do.  Excellent, I don't think we have time for anything else, guys. We have to be respectful of the time. We also, we have Alina here, but we also have Amigad and his suspicious messages  and Amigad is a big boss here as well. So he's here to make sure that we finish on time. So again, thank you so much for being here. Alessio, we can't thank you enough  for being awake at 3.30 or four in the morning and your commitment to be here to answer questions and to participate live. Francois has a very busy OR day tomorrow.  That's why he is not with us. He really wanted to be here.  Matt and Nassimi, always great to be with you guys. So thank you so much for taking the time. Alina, thanks for being here with us and sorry that we went over time.  We always go over time. So there's nothing new there. No problem at all.  Excellent, well, so guys have a great evening and please reach out to us with questions. We put our emails on the chat box and let's do it next time soon.  Have a good night, everyone. Picture.  Excellent, have a great evening guys. Bye, bye everybody.

Video Summary

In the video, a panel discusses the advantages and applications of weight-bearing CT scans in the evaluation of foot and ankle deformities. These scans can be performed in outpatient settings, providing convenience for patients and reducing the need for referrals to hospitals. Weight-bearing CT scans offer a clearer view of hindfoot alignment, subtalar joint impingement, and rotational changes of bone, allowing for better assessment of conditions like collapsing foot deformity, cavovirus deformity, and hallux valgus. They also aid in evaluating instability, arthritic changes, and joint space narrowing. The panelists emphasize the impact of weight-bearing CT scans on surgical decision making and treatment planning, as they provide more accurate imaging and enable precise diagnosis. They discuss the use of software and tools for analysis, and mention potential future developments in weight-bearing CT technology. The panel also addresses audience questions regarding situations when a weight-bearing CT scan might not be necessary and navigating insurance approval processes. Overall, the panel discussion highlights the growing importance and utility of weight-bearing CT scans in orthopedic surgery.

Asset Subtitle

Moderator: Cesar de Cesar Netto, MD, PhD
Faculty: Francois Lintz, MD; Alessio Bernasconi, MD; Matthew S. Conti, MD; Nacime Salomao Barbachan Mansur, MD, PhD

In this webinar, faculty will examine the history, advantages, and disadvantages of Weight Bearing CT (WBCT), and offer tips for utilizing WBCT in your practice and applying the concepts to your patient care. The discussion will also cover future advancements that WBCT has the potential to foster in the treatment of foot and ankle pathologies.

At the conclusion of this webinar, you will be able to:

Define Weight Bearing CT and explain the history behind this imaging technology
Identify the advancements in WBCT imaging for the diagnosis, staging, and treatment of orthopaedic foot and ankle issues
Understand how to incorporate the use of WBCT in your practice and research
Understand the expectations of the technology in the future

Meta Tag

Weight Bearing CT

Content Type Webinar Recording

Year Published 2023

Keywords

weight-bearing CT scans

foot and ankle deformities

outpatient settings

hindfoot alignment

subtalar joint impingement

rotational changes of bone

collapsing foot deformity

cavovirus deformity

hallux valgus

surgical decision making

accurate imaging

orthopedic surgery