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BOFAS Journal Club - Weight-bearing CT: A light shining in the darkness?

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Summary

Join us for an engaging session of the FS Virtual Journal Club, as we discuss the potential of Weight Bearing CT technology in medical practice. Two pivotal papers will be presented offering insights into how this innovation could revolutionize patient care. Among the topics covered will include its use in assessing acute ankle sprains and foot trauma such as Liss Frank injuries, as well as the strengths and weaknesses of the technology. Learn about the varying roles that Weight Bearing CT can play in both acute trauma and chronic instability and understand the impact of its introduction into daily practice. Get ready to participate in a lively Q&A session, and remember - no question is too foolish!
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Description

BOFAS Journal Club

Topic:

Weightbearing CT in the Foot & Ankle

Date:

Tuesday, 13th February 2024, 20:00 to 21:00 UTC

Papers:

Lintz F, Bernasconi A, Ferkel EI. Can Weight-Bearing Computed Tomography Be a Game-Changer in the Assessment of Ankle Sprain and Ankle Instability? Foot Ankle Clin. 2023 Jun;28(2):283-295. doi: 10.1016/j.fcl.2023.01.003.

Najefi AA, Alsafi MK, Malhotra K, Patel S, Cullen N, Welck M. Repeatability of Weightbearing Computed Tomography Measurement of First Metatarsal Alignment and Rotation Foot Ankle Int. 2022 Feb;43(2):260-266.doi: 10.1177/10711007211035387.

Invited Speakers:

François Lintz, Toulouse, France

Ali Najefi, London, UK

Moderator:

Mr James Ritchie, Tunbridge Wells, UK

Learning objectives

1. By the end of this teaching session, the audience will be able to understand the benefits of weight-bearing CT in diagnosing and assessing conditions related to ankle sprains and ankle instability. 2. Participants will be able to evaluate the potential advantages weight-bearing CT holds compared to traditional 2D radiology methods in various types of foot trauma including Liss Frank injuries. 3. The audience will gain knowledge on how weight-bearing CT potentially allows for better visualization of syndesmotic injuries and the changes which occur with weight-bearing. 4. Attendees will be informed about the potential role of weight-bearing CT in the management of chronic ankle instability and its potential use in dynamic imaging, despite current limitations. 5. The session will allow the participants to understand the practical feasibility and concerns of implementing weight-bearing CT as a primary mode of investigation for common foot and ankle conditions in the emergency department and fracture clinics.
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The following transcript was generated automatically from the content and has not been checked or corrected manually.

Good evening, friends, colleagues, non colleagues, enemies and people. I don't like very much. Welcome all to this, the final climactic installment of the be FS Virtual Journal Club for the current calendar year which as we know runs March to March because that's when Be FSS is uh tonight's topic is entitled a Lighter Shining in the Darkness Weight Bearing CT. And we're therefore going to discuss the impact of this new technology on our practices. The evening will follow the traditional format. There are two papers for presentation. Each will be presented by a fellow and then we will have a reflection by the senior author of the paper and then an open floor discussion of questions and answers. So please do feel free to submit any questions you like. If you put them in the messages column, we can then as moderators move them across into the Q and A and have a discussion on that basis. Please feel free to ask absolutely anything you like. There is no question too foolish at all. Please be advised. I do not know the successful lottery numbers for tomorrow at this time. Um In terms of uh speakers, therefore, in a moment. We'll move on to the, um, the 1st, 1st talk. The first paper is entitled, Can Weight Bearing CT be a game changer in the assessment of ankle sprain and ankle stability of which the senior author is Francois. Lyz Francois needs very little introduction. He is truly a luminary, um, not an irradiated luminary, a genuine academic luminary in the world of weight bearing CT. And it's, he's a great friend of BOFA. It's a delight to have him back again. He's currently the head of for surgery at the Clinic De Lion in Toulouse where he fills the shoes of Colombia amongst others. Um He has not however resided all the time in the exotic land of the Rio S. He has spent time in England, um being educated as a fellow where uh he's then obviously been forced to sample fish and chips and other great culinary delights. So bizarrely enough, he went back to France to make his career there. So which is a great privilege as always to have francois with us. Um Without further ado, let's move on. And I'd like to invite our fellow Mr Shah to present of Queens Medical Center, Nottingham to present the first paper. Uh Good evening. And uh thanks to both of us for giving me the opportunity to present at the virtual journal club. This February, my name's Kish. I currently work as a senior trauma fellow at Queens Medical Center in Nottingham Uh Prior to that, I completed a S er for an ankle fellowship er in Bristol. This evening, I'm going to be discussing the paper. Can weight bearing ct be a game changer in the assessment of ankle sprain and ankle instability. A weight bearing CT is presented as an innovative imaging modality that has gained popularity due to reduced radiation exposure, operating time and examination time leading to a decreased time interval between injury and diagnosis. The authors encourage researchers to investigate the applications of weight bearing CT and suggest clinicians use it as a primary mode of investigation for common foot and ankle conditions, particularly ankle sprain and chronic uh lateral ankle instability. So this evening, we're going to be discussing uh weight bearing CT in the assessment of acute ankle sprains, foot trauma, li particularly li frank injuries, high ankle sprains and symptomatic injuries, strengths and weaknesses of the paper and a little bit about weight bearing CT and chronic ankle instability. With regards to weight bearing CT and ankle sprains. Some sources quote that 20 to 30% of all lower limb trauma uh comprises ankle sprains and it comprises somewhere between 60 to 70% of all foot and ankle trauma. Traditional two D radiology er methods may lead to misdiagnoses uh and may often result in unnecessary immobilizations. It's important to note at this point that weight bearing CT uh is does not always mean that the modality has been weight bearing more often the weight bearing CT scanner can be used uh as a cone beam ct scanner to obtain 3D cross sectional imaging without the patient necessarily having to wait bear. Um That being said uh the machine provides three dimensional imaging with spatial resolution comparable to conventional radiography. A uh sorry con conventional CT scanning uh offering potential benefits for diagnosing associated lesions such as fractures and osteochondral lesions, which may be overlooked with uh two D uh two dimensional X ray. Uh This is an excerpt taken from the paper and without reading out the whole paragraph, er it again highlights the potential to miss subtle lesions on plain x rays. The authors support the use of weight bearing ct in emergency departments provided that it is used as the primary means of investigation in all ankle sprains. No, with looking at some of the other injuries such as foot trauma and foot trauma and Liss Frank injuries. There was a 2004 paper reporting up to 24% of Liss Frank injuries were missed on plain film imaging. The 2012 review found that as high as one third of injuries were missed on plain films. And since 2017, there are seven papers all of which have underlined the risk of missing lisfranc injuries on plain x rays alone in a Dutch study. Uh in a level one trauma center, 26,000 patients uh attending the ED department all retrospectively had their x-rays reviewed the outcome was that 1% of fractures were missed, of which 9% went on to require er, further surgery. Another consideration is the radiation dose. Uh A 2021 RCT comparing plain film X ray with a, followed by conventional CT, found that there was a 35% reduction in the radiation dose and a 15% reduction in the turnover of time of patients presenting to the er, in patients who had presented to the ED Department with regards to weight bearing CT uh and syndesmotic injuries. There's a clear benefit in obtaining cross sectional imaging as it will allow to an assessment is that the uh positioned the fibula in the in 20 and weight bearing CT seems to confirm that roughly three degrees of external rotation uh exists and it seems to be stuck as a normal value. In addition, it shows that roughly 1.5 millimeters of posterior translation occurs at the tib fib joint or weight bearing with excellent inter observer variability on weight bearing. There appears to be an increase in the medial clear space er compared to standard CT scanning. Another study seems seems to also show that there's a lateral and posterior translation and external rotation in the fibula in relation to the in 20. Um conversely, another group er have also found that AP translation seems to be better visualized on conventional CT scanning and therefore advocate against the use of weight bearing scans and this perhaps supports the use of the, the use of a cone beam CT rather than a weight bearing ct per se. Another potential application er in the investigation of syndesmotic injuries is the ability to calculate the weight bearing area uh on the cross sectional imaging. And it's been shown that the weight bearing area increases, oh sorry, the er weight bearing over the symptosis increases on weight bearing. Uh and this could potentially lead to a more three dimensional parameter to measure uh as opposed to the er linear measurement. We are used to assessing uh on plain x rays. Uh mainly the tip tip, clear space on ap and morts X rays. Now it would be great if we could get cone beam CT and weight bearing CT on all ankle sprains for foot and ankle trauma presenting to ed departments. But I fear at present trying to implement that would simply break uh the system, considering the strengths and weaknesses. There's clear evidence that injuries can be missed on plain x rays with concern with the imaging of ankle sprains. But the incidence of other mist fractures and lesions is uh is unclear in the literature or sparse at best. A large body of evidence definitely exists um concerning less frank injuries and it is a very appealing investigation in m in the investigation of syndesmotic injuries. But it's not clear whether there is a clear benefit from obtaining a weight bearing CT or simply cross sectional imaging in the form of a cone beam ct or conventional CT. It's also unclear how uh weight bearing CT or cone beam CT could feasibly be implemented in the acute setting. And who would review the images uh would that be radiology, ed orthopedics on call? And given that the standard of fracture care in the UK is to be seen within 72 hours of injury, a more appropriate place uh could uh potentially be the implementation of this investigation in dedicated foot and ankle fracture clinics. With the regards to the radiation dose comparative to one x-ray weight bearing CT still comes out higher. Some sources claim that a less a cumulative dose is applied when all plain x-ray projections are taken into consideration and some sources quote equivalence. Uh for this reason, uh it may be difficult to justify uh investigating, investigating every patient with a query ankle sprain presenting to the ed department with a weight bearing CT. Um Well, what about chronic ankle instability? Well, the paper raises some interesting points. There's lots of discussion about exactly quantifying heel virus and its relationship with uh chronic uh ankle instability which present is not of any diagnostic value or does not aid in the management. Another area that potentially has some applications is dynamic imaging. Um Whilst initially, this appears appealing some of the there are quite some limitations um when trying to obtain dynamic imaging in a weight bearing CT two of those issues are reproducibility um and motion artifact. And indeed, the authors advocate that we may require specific jigs to overcome some of these problems. But at present, it simply just gives an image without being able to add anything further to assessment or patient management. One area may have a slightly clearer role is in identifying and predicting uh which patients may go on to develop osteoarthritis of the ankle. Uh And uh indeed with regards to er the management of ankle instability, uh and uh arthritis, there's a clear benefit because weight bearing CT would allow for the weight bearing alignment, uh in real terms to be quantified. And this may allow for the planning of corrective osteotomies or development of patient specific jigs with greater accuracy uh in total ankle arthroplasty. So, in conclusion, weight bearing CT has a clear role er in acute trauma. Uh And this is evidence based how and where to implement it unfortunately, is less uh evidence based. It's also unclear how feasible it would be to uh go from two dx rays to weight bearing CT as the primary mode of investigation for ankle sprains. It probably has a better defined role er in fracture clinic um for the investigation of Liss Frank and Syders mo injuries. Um, and particularly with Lisfranc injuries. It may be of uh invaluable use as it may allow earlier detection of subtle ligamentous injuries or even subtle malalignments of the list ligament articulation, which may not be immediately apparent on plain film x rays. I think the cumulative radiation dose comparative, 1 to 1 plain X ray or a foot series rather definitely needs to be better quantified, er, if it is to become a primary mode er, of er investigation. Thank you for your time. Uh And I welcome your questions. Thank you uh very much, er, kit um, managing to broadcast through the broadband in the depths of Sherwood Forest. Um, thank you that excellent presentation and the time you've taken with it, uh, we'll move on in a moment to hear Francois's reflect on his paper. I would just remind everyone listening. Please feel free to submit, um, any questions on this topic or perhaps slightly more generally weight bearing ct in for surgery. So, er, Francois, if you wouldn't mind now, er, taking the stage and showing whether it's a reflection on this paper in the first instance. Um, and then we can move on to the wider questions thereafter. Francois. Ok. It looks like my mom. So, thank you, James. Thank you. May thank you everyone for your kind invitation. Um, so it's, it's difficult to, to kind of sum up the whole paper like this in a, in a few minutes, especially, I thought we would have some kind of interaction, but it seems like James is completely off now. I can't see him anymore. So I, uh, so anyway, I will try and just focus on the main point point is that we got weight bearing CT wrong from the beginning because it was named weight bearing CT, but it should have been named cone beam. And what cone beam is, is really a three dx ray. That's why in my view and in the view of lots of people who have been using this technology for years now, uh the discussion about things like radiation dose or uh in practice implementation uh is not due anymore and there's a vast body of proof in the literature uh on radiation dose, on practicality, even on costs and everything. Uh The the the point is that if you consider it as a kind of cool added feature to CT being the weight bearing, then of course, you're gonna narrow your mind uh and your and your vision to very precise uh and specific aspects of our uh foot and ankle specialty. Uh Whereas if you consider it as a 3d x-ray, oh James it back on. Hi James. Um So if you consider it as a um uh a, a 3d x-ray, then there's no other way than implementing it uh as a primary mode of investigation. And uh Kish was talking about system overload. But I think that on the contrary, the system is overloaded. Like when you consider that you miss 10 to 40% of uh small um fractures, major instabilities, uh uh major fractures. I mean, there was one paper in which they, they described up to 40% of mixed missed talus fractures. I mean, it's, it's patients in the end. And if these patients had had cone beam ct in the first place rather than X ray, they, they, I mean, their lives would be different now. Um II II think that's the, this um II was invited to participate in this issue of foot and ankle clinics. And it was a great opportunity to focus on something more of the day to day trauma that we face as foot and ankle surgeons and to show the real benefit of cone beam CT as opposed to weight bearing CT. Uh And this is the question I have brought up with my colleagues all over the world many times. And I propose that we change the name weight bearing CT to cone beam CT or something like a, a broader term that would encompass all of orthopedics because basically everything that is bone cone beam is excellent at showing us. And we, we should use it primarily instead of x rays. That's what I mean. So II advocated for changing the term from weight bearing CT to orthopedic cone beam. Uh and that would be subdivided into um weight bearing CT for the lower limbs and then something else for the the upper limbs because devices exist also to image the upper limb. So II think that we really have to, if that's what I wanted to uh um to say in this paper that we have to remember that where this technology is the most efficient is as a primary modality of investigation in orthopedics for everything. OK. And there is more than enough proof out there in the literature. Uh 11 thing that uh I found quite funny is that uh can you also uh pointed out this uh phrase about Hamer's um uh paper where they found that uh I'm, I'm, I'm reading the paper now, uh anterior posterior translation translation of the fibula is better seen on MD CT. So they advocate that weight bearing is not necessary and could even be counterproductive in I in identifying sic lesions compared with M DCT. OK. And, and I wrote this is a fundamental misunderstanding of weight bearing CT. It's not because the technology was coined weight bearing CT that the examination had to take place with a weight bearing patient. And, and, and there's more to it than that because now we know that uh in external rotation, you get better sensitivity and better um at detecting uh subtle uh syndesmotic lesions. And more than that, it's, that's where new technology comes in. Like distance mapping coverage, mapping, volumetric measurements where you get even more sensitive at identifying those uh subtle syn syndesmotic lesions. So, saying that we should not do a weight bearing CT on a patient who has uh uh a possible syndesmotic lesion and that we should switch to MD CT is just wrong because you'll never get the new tools that you can have with COMBI M CT and the patient is gonna get 1020 50 times the radiation dose that he would get with Comb CT. OK. And this is something that we get wrong most of the time like we to compare weight bearing CT to M DCT. But that's, we should do that. That's wrong. OK. Can, if you, if you can hear me, don't do that, please. Uh And all of you are there don't do that. We should compare it to x-ray. It's a 3d x-ray and it's technologically exactly that. It's a cone beam. And if you do, if you're doing an x-ray, you're, you're, you're flashing a cone beam uh at a film. OK? And there's just one film, one incidence, then you have to move the whole set up around and move the patient around to do another incidence. And we were talking about comparing uh radiation doses but like one single x-ray who does a single x-ray to, to, to their patients, I mean, who does no one? We need at least 234 incidences. And then when you're in, in the, in the trauma department, you always add oblique views because you, you, you can never see that, that fracture that you're looking for and, and you don't need to do that with BM CT colon. BM CT is about 2.5 x rays and there's plenty of literature out there I'll point you to Martin Switcher's paper uh on uh over uh 11,000 scans that he did the five first years of uh of uh utilization. He's the one who says uh the three next indications for with brain CT are the three next patients because it's better than X ray. That's what we should remember. It's not better than MD CT, not for everything. M DCT is still useful for soft tissues. So that would be infections, tumors, soft tissue tumors, bone tumors, maybe so. So MDC still has indications but for everything that is bone, OK, fractures, anything uh arthritis, then Con Beam City is better than MD City and weight bearing city is much better than that. So we should always think that when we're talking about Con City, we're talking about replacing not X rays or CT scans. But this the whole sequence and we've all been through this. We have 100s of patients that have been through this sequence that I sprained my ankle. I go to the E RI get an X ray. They say it's a sprain. I go back home, I'm still painful. I go to see my GPS two weeks after he sends me out for an MD CT scan and the CT scan F finds an unseen. So I've been off work all this time. I didn't get the right treatment in the first place. I mean, that's what we're talking about with this paper. This, this paper is clearly a call for using CT as a primary mode of investigation. That's I could have said the same thing. I'm sorry, I will say this again. But uh a few years ago taxi drivers saw the satellite navigation system arrive and most of them, you know, discarded, disregarded it saying, uh I don't need this. I can read a road map. I know the map of London in my head. II know it. Uh by heart, I don't need this system, but now everyone uses it. Uh OK. It's just better. So and there's uh there's a lot of proof out there in the literature. So I talked about um yeah, system overload, primary modality turnover time. I mean, there's no question about that. Uh And of course, so regarding chronic lateral ankle instability, of course, it's a little bit trickier, but it's also tricky to define OK. It's easy to define an acute ankle sprain. It's easy to define secondary osteoarthritis, but chronic lateral ankle instability is a little bit more difficult to define. So of course, obviously, the, the the the role that this new tag has to play in chronic lateral ankle instability is a little bit difficult to define as well. But uh to give you some insight into the future, we'll probably be able to diagnose uh uh ligament failure before uh osteoarthritis uh arrives before its onset. And also we, we will be able to characterize and, and quantify osteoarthritis. Uh a lot better than used to through distance mapping. For example, distance mapping is, is a 3d volumetric map of the joint space. So not only can you classify osteoarthritis into four stages, for example, but you can pinpoint out exactly how the forces are distributing through this ankle joint and how maybe uh osteotomy procedures that we are very, uh tepid about right now because it's like a large procedure, uh, with an, uh, uh, an on, uh let's say, an un reproducible uh effect. Uh Maybe we'll be able to plan this uh a lot better. So I agree that uh in, in chronic lateral ankle stability, it's a little bit less clear, but it's also a pathology that is uh less clear to uh to um characterize. So I hope I haven't um talk too much and I hope that's enlightened you a little bit. Uh Yeah, I think it gets back to you, James. Well, thank you very much for, for sharing those thoughts. I think we, we can do a little bit of discussion. Um And by the way, uh I must apologize for in my ignorance using the term a weight bearing ct inappropriately as well as the way that everyone else has. Uh At least we are educated on that front and I have to say, uh your, your, your, your passion is extremely persuasive uh on, on this topic. Um There are a couple of questions I think that that one might reasonably ask Um Firstly, uh the uh the availability question you've been in the UK, you are aware of are cash strapped and relatively struggling um system in many ways. Um II, don't think anyone doubts that uh the cone beam CT is potentially a whole new technology with a, a vast variety of applications. Um It is, II suppose the question would be how, how realistic is it really to, to try and have one of these in every, every um A&E department or even in, in every fracture clinic. Um The cost would be considerable. What is your practice in your own department? Do you, do you have a bean ct in the emergency department or are you still taking some plain x rays? II, never take plain x rays anymore. Um And I think that II, th this is my whole point like this. We're thinking it the wrong way round. I mean, if you think about weight bearing CT, you'll, you'll, you'll think about those small indications where you might need it and might be better than uh the traditional sequence x-ray plus M DCT. And so you think I'll never be able to, you know, to, to, to afford it because I'm just simply not using it enough. Uh It's not gonna come come in handy enough. Um The cost is related to how often you use it so we, we can call it weight bearing CTI mean, when II brought up this question of changing the name. Uh You know, all my friends told me now it's too late. It's been coined in literature and, and you know, it's just WB ct now, nothing you can do about that. But then you see it, it results in, in some people that, that go through the reviewing process and publish papers in which they write that it's, it's actually not useful in smo lesions which is utterly, you know, AAA misunderstanding. So, I mean, realistic is it? Yeah. Yeah. II got your question. Sorry, I was just drift, drifting off. Um So it is totally unrealistic not to do it because the, the, the magnitude of the cost savings is just huge. Uh you know, people go through wherever, you know, er, fracture clinic, specialized, foot, neck orthopedic uh uh consultation and they get this, the, the X rays and the CT and it's weight bearing and they get it now and, and it's actually the time savings are huge because in order to shoot ap natural et cetera, you need about 15 minutes whereas the CT is about two minutes. So Martinus Switcher showed in his paper that the time savings are 75% but that's if you use it instead of X rays, not instead of CT. So it's, it's, and I think we, we're not going to compare the French system and how, you know how catastrophically indebted it is. And compared to the NHS, I've been, I've worked in both systems and I, you know, I, I'm not going to criticize my own system uh because you just don't do that. But II never criticized the N HSI. I find it pretty pragmatic. You know, there's a lot of administration uh but it's just these guys don't realize what we're talking about here. This is transform, transformative, but it is, if you implement it, you don't realize how good it is. If you don't implement it. And in my own practice, I've been using it for six years. Never going to go back. And I'm never asking for a, for a standard X ray anymore or a. Thank you. Thank. Thank you. That, that, that's very helpful. You've told us try to how to try to sell it to our administrators, um which, which is, is quite helpful. Um II think there's er clear little doubt as to its benefit for things like picking up, you know, Mr these Frank injuries and so forth. Um I'm going to, we're going to have to move on in a moment, but I think one final question from the floor from Mr Sandeep Kapoor, uh who I think is perhaps plagued devil's advocate a little bit. He, he asked the question that um uh again, he's, he's talked about weight bearing, but I suppose one could put the same question for, for, for, for a um a cone beam CT, which is if you can, if a patient can take a weight bearing X ray are the additional fractures you're picking up with the cone beam ct, be it weight bearing or not ones that necessarily require intervention or ones which might perhaps be no great loss if they're not necessarily picked up. I think we, I think he's talking about the ankle injuries rather than things like Mr Leron and so forth. So I'm not sure I got the question very well, but I think I, well, the way I understood it, I'm sorry if that's not the question as it was meant. But is it really a problem missing all these small fractures? I think that's the way I understand it. I think it is because it results either in delayed immobilization if even if you're not going to the, or it results in delayed immobilizations and worst functional results for some patients or it results for ex excessive immobilization because we, we see both in our clinics. I mean, people who have had a simple benign ankle sprain and you see them at three weeks and they're still walking with crutches and, and, and a plastic cast and you know how devastating an effect this has on their function and how it's going to be difficult for them to rehab out of this. And we see the opposite. We see a liss prank fracture uh that has been walking since the beginning because he's not too painful and that doesn't seem to be a problem, but now it's displaced and you're gonna have to go to the or so. Uh I don't, this is obviously very difficult to demonstrate but uh I think it's too good a reason to stick to the old way of doing things to give it any credit. I think the technology you said, like I gave you good arguments to kind of sell it to your administrators. And you said my passion is great. II, II think that's great. I love to hear that. I, you know, I'm like everybody. I just II like the praise. But the thing is that the technology is so good. I don't need to say anything. Uh um It's just II just wish that we had coined it differently, not weight bears city but cone beam like and, and really think everyone, the dentists have been using cone beam for 20 years and they're very happy. They never went back to X ray. OK. Um So, so I mean, why can't we do it? It's just something's locked up in our brains and those of our administrators, we, we, we, we, we, we need to stop focusing on very high end specialized foot and ankle stuff, but we need to consider the immediate benefits for every single patient francois. Thank you very much that, that's great. It's a joy as always to have you on. And uh I think we now appreciate much better the value of this wonderful technology. So um it's time now to move on francois. Do please feel free to, to stay for the rest of the discussion. Um But I'm grateful for you disrupting your family holiday. So I entirely understand if you have more pressing calls. Um I'll hand over now to my colleague Nigel Veer Kti who's going to chair the second half session and the second paper. Thank you. I'll stay on. Ok, thank you, James and thank you Fran. Um We'll move on to the next paper uh which is a paper on a very niche application of the weight bearing um element of cone beam CT. There is a paper from Ali Nafi and the team at uh Stanmore uh repeatable to your weight bearing CT for first metarsal alignment and rotation. So this is being presented by Far Salbi who is a fellow at East Lancashire. And after he is presented, we'll have uh Ali joining us uh to give his thoughts and reflections on the paper. Ali is a consultant uh for surgeon at the North Park Hospital. And after uh his uh CC at the Stanmore rotation, he completed fellowships at uh Oxford Kings and Stanmore. And uh he's published a lot over 30 papers. And uh his latest series of papers have been on uh first metatarsal pronation and one of them has won him the bofa's Prize. So I'll hand you over to FRA who will uh present lie paper for us. Thank you. Hi. My name is Vira Elvera. I'm a foot and ankle fellow. At East Lancashire Hos Trust. Today, I'm going to present a paper for the virtual journal club for the Bovis for this BOS meeting. The paper is about the repeatability of weight bearing ct scan measurement um of first met alignment and rotation. The paper was published in October 2021. Just a quick background. Before we dive into the paper, the 4 ft measurements um such as hallux valgus angle and intimate tarsal ankle have traditionally been um uh traditionally been assisted using weight bearing bridge gras of the foot. The accuracy and drug reducibility of measurements are highly dependent on standardization of the position. The assessment of the rotation of the first met grade geograph is operator dependent and unreliable. CT scan is increasingly used to assist the alignment and rotation of the first metatarsal. The reliability of the measurement of of measuring the first metatarsal alignment and rotation on sequential weightbearing CT scans performed on the same patient has not been assessed before. The first metalation was found abnormal in one third of the patients with heparus. And this is according to a study done um by um the same group uh before another study um done by the same group before, has shown that scarp ostectomy doesn't correct. The first metatarsal coronal rotation and worse outcomes are linked to a greater postoperative metatarsal rotation. So the rotation of the of the first metatarsal needs to be measured and considered when planning heu valgus surgery. The Radiological assessment of the co um of corona rotation of the first metatarsal is mainly done by using two angles, the alpha angle as you can see in image not a uh image A and metatarsal coronation angle in image B. For those two type of images we take um reference from the floor. So the aim of this paper was to establish the repeatability um test three test of measurements of first met alignment and rotation in pa in patients without 4 ft pathology, we bear CT scan. It's a retrospective study, a single center and it uses a sequential weightbearing CT scan of studies uh with less than 12 months apart. And eventually, it has included 42 patients, uh sorry, 42 feeds and 26 patients. It has analyzed a list of all the weight bearing CT scans between 2013 and 2020. Um and then uh identify uh the um group have identified all the duplicate scans and then they have assist the patient notes and the list has gone through the inclusion and exclusion criteria. There was no identification of the pathology for which the patient was scanned and the patient foot position in the scanner also not standardized. And then the inclusion criteria was patients who are eight, more than 16 years old, who had two weight bearing CT scans within one year of each other and had not had any surgery for the foot um or ankle between scans exclusion criteria was patients with surgery between scans previous both for surgery and heu rigidus. So initially 52 ft, 26 patients has been identified, 10 ft has been excluded because of he's rigidness and 42 ft included, of those 42 ft included 26. Um There was no indication there was just because they were scanned for the opposite side and 4 ft, there was scanned for postoperative assessment of union mainly following alpha DC surgery for the hind foot. 2 ft has been scanned after PC and P planus reconstruction and two forte lesions like A V and and CD lesions. So identifying the scans and patients for assessment was done by 2 ft and ankle trained orthopedic surgeons and all scans were checked by both surgeons. The radiological measurements, uh The data sets were obtained using a pit cat unit from the outpatient department. Um The data sets were anonymized. All measurements were performed by 2 ft and ankle trained orthopedic surgeons, the Hero valgus intermetatarsal angle and later Mars angle were measured using previously published methods to better define the study population. And the uh metatarsal pronation angle and alpha angle were measured as well to determine intraobserver reliability. 20 random feet were selected for measurements and repeated one week apart by the same observer to determine the interobserver reliability. 20 random feet were selected for measurements and repeated by two different observers. As we can see in this um table. The Halo Valgus angle uh measurement between T one and T two. almost the same. So this one was 1 to 15 and T two was 0 to 15. Um interatarial angle. Again, the measurement was almost the same 4 to 10 and 4 to 10 and two tests. The mears pronation um was very close readings between the two tests minus 12 to 13 and minus 10 to 14. Um On the positive side means that there is pronation on the negative sides means there is no um and the alpha angle was 10 to 15 on T one and 10 minus 10 to 17 on T two. The test re test reliability was good for um was excellent for angle and uh for ation angle and was good for inter and angle and that was using the interclass correlation coefficients. Mhm So, um as a result, the Halo valgus ranged from 1 to 15 degree and the in metal angle ranged from 4 to 10 degrees. The inter observer agreement was good for meals pro angle and alpha angle measurements and excellent for Hero Valgus and intermetatarsal measurements. Um In Interobserver agreement was excellent for he valgus, metatarsal uh formation angle and alpha angle and good for intermetatarsal measurements. The measurements for first metatarsal alignment and rotation using metatarsal pronation angle and alpha angle are reliable between cells and repeatable between sequential weight bearing CT scans in patients without for pathology. This diagram shows that the for the vast majority of the number of patients. The difference between T one and T two measurements between uh for the metalation angle and an angle um was very minimum. So, small changes in the foot position have not been shown to affect the re reliability and agreements between scans or me for the measurements. The the test retest reliability for hallux valgus intermeal angle and metatarsal pronation angle and alpha angle were between excellent and good. These small differences may also be attributable to changes in the foot position in the scanner going to the strength of the study. Um First of all reliability of measurements. So it demonstrated high inter observer and inter observer agreement for key measurements uh like MPA and it provides confidence in the accuracy and consistency of the data test retest reliability. It established a strong test retest reliability for the various measure parameters like hero valgus angle angle MP A&E angle. It indicates the stability and reproducibility of measures over time. The last point um it has utilized the weight bearing CT scan um allowing for detailed examination without the limitation of traditional um radiographs and offers comprehensive assessment of the first metal alignment and rotation. Regarding the limitations of the study, there has been um heterogeneous indications for scanning um with different hind foot. Um and hind foot pathologies mainly um the retrospective design and small sample size. Um so limited by retrospective nature of the study and small sample size may affect the generalizability of the findings and statistical power regarding the foot po position. Um there were lack of standardized foot positioning during the scanning. Um There was some in inclusion of some patients with a painful ankle conditions. Um um or possibly painful conditions like patients who still haven't had um healed arthrodesis need for further research, call for larger pros prospective studies with the standardized protocols and we need to explore the clinical significance and application of findings in different patient populations. Thank you. Thank you very much for us. Thanks for a very compact uh concise presentation of that paper. I'll hand you over to the senior author, Mister Ali Najafi um to give us his thoughts and reflections on this particular study. Thank you. Thank you for Rose for the er presentation and thank you Nigel and James and be fast for the invitation. Um I also thank you to my colleagues at Stanmore for, for the work that we've done on this, which is a series of papers looking at first metatarsal pronation and um using cone bean weight bearing CT to basically try and establish a pattern in normal and abnormal patients. But this paper in particular was it was something that we did to sort of try and lay some of the foundations in terms of how we measure it. Um uh So we reviewed our, our literature to start with, to look at what the best measures were. And actually, as, as we heard earlier, we use metatarsal pronation angle and alpha angle. Um But I think it was very important that if we were going to go ahead and look at normal patients, abnormal patients, look at pre and POSTOP measurements that we look at the repeatability and reliability of a test, uh assessing these measurements because otherwise we don't really know if we're putting two or measuring twice and actually getting different results and whether that's significant or not. So I felt that this was an important step to try and establish that and establish what, what was, what was normal and what was abnormal. So the purpose of the study really, in terms of the reliability aspect was to look at the inter and intra observer reliability, which we, we showed was good and excellent for the majority of, of measurements that we took using weight bearing CT. Um But the, the key message was really the repeatability aspect of this. So the repeatability was was when we had patients who had two sequential weight bearing CT scans. And when we look at the statistics in a bit more detail, the standard error of measurement was just looking at the, the sort of the, the error rate or the based on the standard deviation of the interclass correlation coefficients. And then the MDC 95 which is a minimally detectable change. It's basically a 95% confidence interval that gives you an idea that within 95% you you're 95% confident that if a, if a measure falls within this number that, that it's, it's reasonably accurate. So if I give you an example, if we measure a metatarsal pronation angle in a patient and it's 10 degrees on the scan today and, and we don't, and we do the same scan on the same patient in a year and it's 12 degrees or 13 degrees. We know that all of that is probably measurement error and, and their pronation hasn't changed, you know, they haven't suddenly developed more pronation or less pronation. It's just that, that probably all comes into measurement error if you measure it today and it's 10 degrees and the next time in a year's time you measure it and it's 16 degrees. And actually, that is probably that their me pronation has changed. Um And actually, that's, that's how we now know the difference between what is error or measurement error in what is um actual pathological changes in a, in a patient's bone morphology. So I feel that that's an important step before we sort of go on and and publish more, more information on on this topic which um is, is expanding and certainly is, is growing in in, in uh in the discussions regarding helix valgus regarding issues around recurrence, um issues around um pain or first metatarsal, medial metatarsal sesamoid arthritis. Um and actually whether this pronated metatarsal is a contributing factor to that. And, and certainly some of our work has gone towards looking at that. And, and one of the, one of the papers that we, we used this sort of repeatability measure really was in a sense, was looking at our scarf patients and, and it was a reasonably small series, but actually, we showed that patients who have a pronated metatarsal before they have a scarf osteotomy have the same pronation after a scarf osteotomy as, as we know, a scarf isn't really a rotatory osteotomy. It's just sort of as a more shifting um than rotation in the, in the coronal plane and they do badly. So those who have a, a sort of malrotated metatarsal to begin with, have a malrotated metatarsal to end with, but they're the ones who have the worst outcome score. So there is certainly something to mm pronation of the metatarsal. Um We've shown that 30% of patients with Hali valgus have pronation which is abnormal compared to our, our normal series. So there is something to that. I think there's a lot of work being done at the moment, looking at patients who've had lapidis for derotation in er, of their metatarsal patients who are having um proximal osteotomies and also with mis. Um I think that's another area where there's rotation, rotation that is built into the oblique osteotomy that's done doing mis Hali vs correction. So that is also something that I think a lot of the teams are looking at. Um So that's, that's somewhere where there's a lot of room for discussion. And, um, and what happens next. And I think that sort of builds into the, when we talk about the repeatability of our paper, we looked at, you know, the statistical differences. So minimally detectable change and errors of measurement. But actually, we couldn't establish the minimally clinically important difference, which is what is significant, you know, is there a, does five degrees matter or does 10 degrees matter? We don't really know um when it comes to pronation or, or not, but I guess that's a question that hopefully will be answered in the near future. Thank you, lie. Um So just I'm just going to um look at the weight bearing city concept in a wider perspective. Obviously, you have gone into a very niche area. Now, Franco has talked about the nonweight bearing use of a cone beam CT in trauma. Now, on the other hand, you have the weight bearing application for electro foot surgery. So for example, uh looking at hind foot pathology, hind foot alignment or, uh you know, when you manage, uh when you plan your treatment for someone with a flat foot, so who gets a fusion or, or who gets a corrective osteotomy and reconstructive procedure. So, in your experience, what has been the application weight bearing CT for such conditions, you know, elective orthopedic conditions? Well, I II think it's um it's a very useful modality just to establish the position of the foot before you're doing corrections, especially when it comes to PS Planus pes cavus. You know, we use it routinely at Stanmore for those conditions. Um And certainly more so now with midfoot problems and certainly those with, with forefoot problems as well. And, and the reason for that is there is a number of studies that show that positioning of foot bones change on weight bearing. So the, you know, when we, when we're, you know, when we're assessing a patient with a flat foot, obviously, you know, the, the, the the key to teach R Fr CS or, you know, orthopedic residents and registrars is, is, you know, get them standing, you know, have a look at their foot standing, have a look at the deformity, standing hind foot alignment. But then we take our measurements off a non weight bearing MRI or a non weight bearing CT. Um And, you know, intraoperatively, you can't re whilst we obviously can simulate, uh you know, you can sort of see the heel position and you can see what you've corrected. It's not the same as a weight bearing scan as such. So I think it gives a lot more information and, and weight bearing CT is, you know, we looked at the um hindfoot alignment with relation to 4 ft metatarsal pronation. So we could really map that out. So I think with flat foot positioning, you can also see the whole arch. So you can see where the collapse and the deformity is, you know, where the pronation deformity is happening where there is collapse or is it the tail and navicular joint, the sagging more, you know, what is the first TMT unstable? Is that something that we need to address as opposed to a cotton osteotomy? All of these things can be answered through that. And certainly the abduction abduction part of a flat foot, how much correction we need to achieve is something we can measure more reliably using a, a scan. And, you know, we've shown that, you know, this is repeatable and reliable, but it can probably be repeatable and reliable across all conditions. And, and it gives us an idea of how we do that and going forward like Franco I mentioned earlier, you know, we can, I think there's, you know, scope for things like mapping bones and, and assessing bones in greater detail to, to assess that. And I know that the team at ST have been using weight bearing CT in combination with uh specifically looking at our cavus deformities and the Chakra Marie tooth deformities um so that we can evaluate those in more detail and basically plan our corrective osteotomies accordingly u using that. So I think there's, there's a lot of scope for that specifically in the deformity correction er world. Yeah. Yeah. Yeah. Again, um yeah, coming back to comparing both your views, um obviously, Francois is quite passionate about using this acutely for trauma and just, you know, replacing or, you know, plain x rays. Uh We can't see that happening in the UK in the foreseeable future. But I think there's a great scope for use in complex deformity correction. So, although we haven't had many questions from the floor, I can see, I can, I can imagine a lot of our colleagues listening to this thinking, OK, sitting in a average KD GH and managing standard, you know, pesca, pesca and uh adult flat foot. Where do I, where, where do, where does weight bearing city come in? So is there a scope for sending such complex cases to our regional tertiary unit? Um say in, in your area stan for example, and uh you know, getting a weight bearing CT and liaising with you in our MDT help use the weight bearing C results to plan treatment. Is that something that can be practically uh you know, used? Well? Well, I think, I think it's um I mean, on a practical level, I think the um I mean, there's a few ways of doing it. I know that the the weight bearing CT team are sort of offering, you know, you can, you can almost buy a bundle, you know, like, like, you know, you can get 10 scans for example and, and you, you should use them sort of as you need them, for example, for those specific cases, I know certainly in where I work. It wouldn't be something that I'd be doing routinely. It's just at the moment not feasible. Even though I completely agree that there is a really strong argument with those acute trauma patients and other patients that we should be doing it more. Um, it's just, er, so for me it's very selective, um, on the patients that I feel that I can't fully establish what I need to. But I guess it's, it's very different between regions. But II think it's, it's just, I think it's worth bearing in mind. There are, there are those patients that maybe come back, they've had an operation, they need revision, sort of something else. You know, they're not quite something doesn't look right. They don't, they've got a slightly odd deformity and, and I feel that it just adds to the picture and it just means that we can provide, you know, ultimately the best patient care. And, you know, we come back to GT, which is very much our, our, our thing, you know, getting it right. First time. If, if we have the information that we need, then then we can get it right. So it comes back to that. Really? Thank you very much, Ellie. Thank you very much for your insights and for the wonderful paper and thank you for us for your presentation. Um I think James Camera come on, which is a subtle signal for me. Uh So you back hand the chair back to James or, or need a not so subtle signal. Um Thank you Nigel. Uh As always uh for your, for your great contribution. I think we need to wind up. But just before we go, I think Francois uh is, is desperately keen to share uh a brief insight with us Francois. Hey, uh I just want to thank you guys and uh ay, thank you for that paper. It's great. I think you showed the intrinsic reliability of the technology, the ability to repeat measurements and always get the same measurements on the same patient unless something has changed. The only thing I II can't agree about is that some of these changes can come from positioning of the foot inside the machine. That's, that's not true. The machine is, is, is a fixed setting and it doesn't change relative to the foot. So if your measurements change, it has to be because of intrinsic changes within the foot. And that's what you're trying to point out. And nil you, you said we can't see that happening in the UK in the foreseeable future, but you need to change that mindset. Your administrations. They will only listen to you if you're convinced. OK. So if you don't see it happening in the view, who will, I mean, it's the patients don't, they, they, they're not aware. So, so you need to change this mindset and I can show you the French NHS is not richer than the bridge, the British NHS. But we have this thing is that the reimbursement is for x rays. So it allows us to replace x rays by uh uh CT S. So, so because we do a lot of them, it pays for the devices and, and the patients are the ones that get all the benefits. So we, we need a change of uh mindset here and, and just to finish in, in the chat, I was looking at the chat but our, our, our colleague who asked the question, he said, I think limitation of weight bears to in trauma is that the patient cannot bear weight. That's exactly the thing I was explaining before. You don't have to have him bear weight. You can sit him in the device so you can lie him down and, and put his uh his foot through the donut. You don't have to bear weight. So we shouldn't call it weight, bear ct anymore. Three DX ray for every patient. Thank you. Thank you f I hope your passion is contagious. It's not my passion. It's just the technology is just great. You go for it, forget everything else. Thank you very much. So, so there, there you go, Nigel. That, that's all you need. Free your mind and the ass will follow. Um So we have to do is, is, is dream and convince everyone that this is the way forward because the technology sells itself. Um I think we are over time. Uh ladies and gentlemen. So um a couple of housekeeping announcements before we go, uh firstly for all participants to obtain your certificates, please click on the feedback um button which is on the top right hand corner um of your screen that will take you to the feedback. Once you fill that out, you'll be automatically sent your certificate. So there's no QR code to scan this time around. Um This is the final um uh presentation in this series of webinars. The um next one will start in will be in May and uh we'll be discussing at Belfast where we take the subject matter. If anyone has any suggestions, please feel free to come and butt and hold me or nil or anyone else over a coffee or whatever is topical in Belfast. Um And we'll take it on from there. So I think it remains only for me to thank our presenters uh Kalish Shah and Farez Albida. Uh also um our senior authors Alena Je and Francois Linz, my long suffering coa Nigel Vasi so well done Nigel for keeping going and behind the scenes. If you forbid, forgive me for mixing my metaphors. Um paddling hard to keep the show on the road are colleagues in the media committee, it committee May Abidi and Tom Ankers and as ever lurking even more behind behind the scenes, the shadowy figure of Mr Robert Clayton. Uh Thank you all folks very much. And uh I wish you all a very good evening. Bye. Brilliant, well done.

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