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Hi, everyone. Uh, I recognize some names and some faces but others. I don't know. Um, I'm Liz. I'm a lime recon surgeon working at the Royal National orthopedic Hospital in Stanmore. Um, and I was an east of England trainee, um, a little while ago. Um, so I think we have, I'm going to aim to do about an hour or so of telling you a little bit about um F ri and Osteomyelitis. We'll start kind of bigger broad talk about diagnosis and diagnostic criteria. We'll do a bit of pathophysiology and then kind of management principles and what I think I might actually do is come back to doctor Nickerson's cases and just go through those. Um, and look at them a little in a little bit more detail with a kind of a surgical eye on them if that's ok. Um Feel free to, if you've got any questions or want to stop me as I'm going through, please feel free. Uh How much I, so I wanted to start a big picture with this. Um Can you give me a little thumbs up in the chat if you are aware of the global burden of disease study from the lancet. You just a little thumbs up in the chat. Have you heard about the global burden of disease study? Uh, never heard of it. Yeah. So, I haven't got any thumbs out. That either means you're all still having coffee, uh, or nobody's heard of it. Is it really not a single person who's heard of this? Ok. Um, 11 task for you all. Then when you, um, finish today, uh go go Google global burden of disease, it basically tells us what people are sick with across the world. So I know as orthopedic surgeons, we think that the only ailments are orthopedic, but in actual fact, people have all sorts of ailments. Um and it is good to know about those and good to have a kind of an understanding of, of what happens in the world. Um disease wise. So this is basically a study that's been running for quite a few years. Um And it looks, and it looks at disease patterns profiles across 204 countries and territories. Uh Most recent set of kind of data is from around uh 2019, 2020. Uh And what they looked at for this particular bit of analysis was the mortality that's associated with bacteria. So super interesting bit of work and basically most of the infections around the world that kill us in terms of bacteria can be kind of condensed down into 33 bacteria. Um So in the year 2019, there were almost 14 million deaths related to infection. Uh and seven, slightly more than 7 million of those were associated with those 33 bacterial pathogens. And the five leading pathogens in the world were Staph aureus, e coli strep, klebsiella and pseudomonas. And those were responsible about for about half of those deaths. Um And staph aureus is the leading bacterial cause of death in 100 and 35 countries in kids. It's the strep pneumonia that's more problematic. And I put this slide up there because I think quite often, particularly as orthopedic surgeons we talk about and we think about staph aureus, like it's just a bit of a nuisance, but in actual fact, it kills people and it kills a lot of people. Another element of the global burden of disease study uh has looked specifically at musculoskeletal disorders. Uh So there's a big study that looks at like the the major musculoskeletal conditions. So, rheumatoid arthritis, osteoarthritis, back pain, neck pain, and gout. But then they've also looked at this other category called OD, which is other musculoskeletal disorders. Uh And there are about 500 million people living with other musculoskeletal disorders. Um and within the other musculoskeletal disorders is where we find infection. So, osteomyelitis, fracture related infection. PJ I, this is a really, really helpful little infographic just to wrap your head around all the different terminology that we use related to bone and joint infection. It was published only, I think last year or maybe a year and a half ago. And I think just really super helpful to make sure that you're using the right words for the right things. So across the top and blue, we've got bone infection and bone infection and further categorized into Osteomyelitis and fracture related infection. Um In red, we have joint infection and that's either septic arthritis. So native joint septic arthritis or you have the pjs, the periprosthetic joint infection. Um And for the blues and the reds, you've got both acute and chronic. There's a bit of discussion about whether that's really a helpful division into the kind of acute and chronic, but that's where we are with that. And then uh spine has its own section. And for spine you've got implant, associated stuff. So, implant associated vertebral osteomyelitis and then you've got infectious spondylodiscitis. So I think whenever you're thinking about infection, if you can just kind of have this little um infographic in your mind about, am I dealing with bone? Am I dealing with a joint or am I dealing with spine? I think it's quite helpful to make sure that you're talking about the right stuff and you'll find that different categories of orthopedic surgeons deal with different things. You know, if you're doing a general on call, you need to know something about everything. But once you're kind of in your consultant practice, you'll be quite niche as to whether you're dealing with bone or you're dealing with joints or you're dealing with spine. So I'll just talk through them. Um Each, each of those just in terms of nomenclature. And I'm going really back down to basics because in my training, nobody really went through the basics of this with me. So hopefully it's helpful for you. So, osteomyelitis is essentially inflammation of the bone and the bone marrow. Uh as a result of an infection, septic arthritis is an infection of a native joint and then fracture related infection is literally a fracture plus an infection. The fracture could have been at any time point and the infection can also be at any time point. But if you have both together, it's a fracture related infection F ri um and this is a relatively new entity and then a relatively new definition. So this paper looking at a definition is only from 2018. So this has kind of been in in my lifetime that this has arisen as an entity and people study this and look at this separately. So that's F ri and then we also have PJ and PJ I has been around for a lot longer as an entity. And people have talked about prosthetic joint infections for a lot longer and this is the kind of schematic of the diagnosis. I'm not talking about PJ I today that really ends up being in the realm of the arthroplasty surgeons. Most of the time, but just be mindful that there is quite a lot of overlap in how we manage stuff, how we talk about stuff between F RI and PJ I the consensus papers, if somebody mentions that to you, you're now kind of getting into the detail of fracture related infection kind of practice. But the consensus papers are basically a set of papers produced between 2018, 2020 from an international expert consensus group. And they looked at definitions at diagnostics, at management and I've summarized them there for you as a little grouping and it's kind of bringing together best evidence best. Uh you know what, what we know about F ri I can share these with you afterwards, this level of detail in terms of knowing about these consensus papers, you're unlikely to get asked about this in the exam. I would imagine uh if you decide you want to become a limb recon person and a bone infection person, then you need to know about them. I don't know how much Doctor Nickerson covered about the kind of pathophysiology. But this is like bone infection pathophysiology from an orthopedic point of view, which is hopefully helpful. And the way I think about it basically is that the pus wants to get out and whilst the pus is wanting to get out and do its thing, the bone will continually and always be trying to heal. And so the changes that you see in bone are a result of those two things, they are a result of the pus wanting to get out. So build up of pressure, trying to find a gap a way out of the confined space that it's in and then the bone wanting to heal itself. And so what you end up with that, you're able to see either intraoperatively when you're looking at the bone or on x rays. Um most often are features in keeping with that process of pus trying to get out and bone, trying to heal. So what you have in the pus, trying to get out, you might have a subperiosteal abscess and somebody was asking about kind of a collection under the surface of that intramedullary nail of the tibia. So you might have a subperiosteal abscess. And so the periosteum kind of lifts itself off. So you might have the collection of the soft tissues, but you might actually have the pus just under the periosteum. So it's able to lift the periosteum away from the cortex. Uh the result of pus then kind of leaking out through that will be that you get a little clo acre. So the bone, you'll get a defect in the bone and there's basically a hole in the bone and that's called a clo aer the bone that it leaves behind or the bone that is then totally invaded by infection and loss of blood supply will die. And the dead bits of bone are called sequestrum. So they basically get stuck inside, they're dead and they will do nothing except for continue to be an nus of infection. And then the other bit of the process I mentioned was the new bone trying to heal and the new bone trying to heal and wall off what's going on is called the involucrum. So the involucrum is the new bone that forms around the pus, around the bits of infection and around the sequestrum. Somebody could very well ask you about those three words, cloaca, involucrum, and sequestrum. How do bacteria live in soft tissues and in bones? And there's two main ways that we think this happens and this is a lot of kind of original basic science research that is still evolving and still developing. So one way that bacteria live in bones in this and in soft tissues is in a planktonic state. So they're basically swimming around freely, they're mobile, they're small, they're moving around the other way that bacteria may be living in soft tissues and bone are as part of biofilm. So a biofilm is an organized community of lots of bacteria embedded in a kind of a polymer matrix that are usually attached to a surface. And biofilm has been the enemy of orthopedic surgeons since time in memorial because biofilm is what you get on foreign bodies. Biofilm is what you get on plates, on screws, on nails. And it's why we think just treating with intravenous antibiotics is not enough because you can't, those antibiotics won't penetrate into this biofilm. The only way you disrupt this biofilm or get rid of the biofilm is by physically scraping it off or taking out the metalwork, which is probably why leaving an infected nail in situ and just giving lots of antibiotics doesn't work. And part of that we think is because of this biofilm. Um there is however new evidence emerging that maybe the biofilm is not as important as we think it is. And there's a really a kind of keynote lecture last year at the European Bone and Joint Infection Society where somebody presented a talk, the title of which was the death of the biofilm. So it might be that the biofilm we've overstated its importance and probably what's happening is there's a kind of a microenvironment between the bacteria, the metalwork, the bone, the soft tissues. And if you can interfere with or adjust that microenvironment in some way, you then change what the bacteria do. So it it might be that in a few more years, we talk less and less about biofilm and we talk more about the microenvironment. So back to what's actually useful for you to know uh what, what do you need to know about fracture related infection? And how do you arrive at a diagnosis? I think the diagnosis actually can be super simple. So first question to ask yourself, was there a fracture or was there a fracture at some point. If your answer to either of those two is yes, you're kind of 50% of the way there to the diagnosis. Then ask yourself, is there an infection? And if you, if the answer to that question is yes, then you have a fracture related infection. So, is there a fracture now or was there a fracture at some point in the past? And do I now have evidence that there is an infection that's a fracture related infection? And then I would add a third question there. Uh because you need a really, really low threshold for, for diagnosing this a low index of suspicion. Could there be an infection? So there was a fracture in this tibia about five years ago, the patient's now presenting with pain. Could there be an infection if your answer to that question is yes, then it's a fracture related infection. Ah It kind of one of those you have to rule it out rather than it being a rule in diagnosis. So pretty much anything that comes to me I think could be an infection until I've proven otherwise if somebody says to you, yeah, it's probably not always be suspicious of that as an answer. Your algorithm for fact related infection diagnosis is this and this is from one of the consensus papers and I'll just talk through it. But basically you've got your initial clinical history and examination, you've got confirmatory and suggestive criteria. Then you do your surgery and then again, you've got confirmatory and suggestive criteria and Dr Nickerson might have gone through some of this already. So, suspicion of F ri, is it possible that this is an infection? Is it possible that this is an infection related to a fracture? Your confirmatory criteria are, uh there's a fistula, there's a sinus or the wound hasn't healed or the wound is broken down, uh or there's pus. So if you think this might be infected and there is pus, it is a fracture related infection, it's kind of that simple suggestive criteria or other kind of clinical signs. So, is there a bit of redness, is the patient systemically unwell? Uh Do I have imaging um results that would suggest this is an infection? Is there a new joint effusion are inflammatory markers raised? We'll talk about those in a little bit more detail in a minute. Um And is there persistent increasing or new onset wound drainage? Those are suggestive criteria. If you then do surgery, you've again got the same kind of two colons suggestive and confirmatory. On the confirmatory side, you need at least two separate samples uh with the same pathogen uh or histopathology that says that this is an infection. Um and that would be five polymorphonuclear sites on histopathological examination. Uh Suggestive criteria are if you have one deep tissue sample that's positive. So, confirmatory is at least two and suggestive is one. So I hope you can see there that you really don't need very much to diagnose a fracture related infection. And if the thought has crossed your mind, you are kind of duty bound to exclude it. And the other paper around diagnosis is this one and it really just to summarize this stuff into this little table that says, always consider fracture related infection. Think about suggestive and confirmatory signs, inflammatory markers are really not that helpful. If you want to make the diagnosis, the nuclear medicine scans are better than an MRI. And it's useful to use histopathology to help in your diagnosis. Presentation wise, I just divide this into history and exam just like you would for any other orthopedic condition. So in the history, they're going to tell you I broke my tibia, the wound wasn't ever quite right. Some of the stitches had to come out, there was a bit of liquid and now it hasn't healed and I don't know why it hasn't healed. That's probably a fracture related infection. Obviously, history of an open fracture should raise your index of suspicion that this might be a fracture related infection in general, any sort of wound problems. And you often have to ask for it. Specifically, patients tend to think that you know, stitches falling out or a bit of pus and a bit of liquid is kind of normal, it's not normal. There's been a wound problem, you know, be worried, uh pain, often a feature of it. Uh, general kind of if they've got risk factors for having an infection. So poorly controlled diabetes, poorly controlled HIV, use of steroids, that sort of thing. Most fact related infection patients or chronic Osteomyelitis patients are depressed and anxious. Um, all of mine get a psychology review, um, ask them how often they have to change their dressings, uh because it'd be discharged and it often smells really bad and that's often the most concerning feature for patients is the bad smell. Examination wise, I've put pyrexia there, just make sure they're not systemically unwell, make sure they're not septic. Um always have a look at the soft tissues, see whether there is a wound, see what the scars are like. Can you see a sinus? Does it look like there's something that might have been a sinus at some point that is now dried up? Also super common, always check for the range of movement and the joints involved. Um You might see a bit of generalized erythema, a bit of swelling. Um and always check for the neurovascular status because it's just part of any orthopedic examination. But also for your surgical planning. And for the plastic surgeons, you want to know if there's foot pulses, presentation wise, you'll probably see in the literature and people still do talk about this. So they talk about early, delayed and late. So early is within the first two weeks. So early wound healing problems, you know, before all the stitches have been removed. Delayed is that sort of in between period between 3 to 10 weeks and then late is beyond 10 weeks. There was some suggestion possibly that the timing of presentation made a difference to the bugs you might encounter. And there's also a suggestion that the timing in these categories might help guide you towards whether a dare would be appropriate or not. And we can talk about that. So I've just got a few pictures here of various sinuses that I have and these are all chronic fracture related infection patients. So I hope, I hope these are big enough. You'll be able to see um picture here all the way on the left of the screen is a proximal tibia with a discharging sinus here. And it's literally just posing out pus and that's probably been there for about three years. The guy in the middle with the femur, that area of ulceration and that sinus has been there for about 15 years. So in him, I'm a little bit worried about a malignant transformation of that sinus. So for him, I would be sending that away for histology. And then the one all the way on the right hand side has had a vac on this wound for about six months and it hasn't healed. And when I took her to theater, it was because the anterior compartment was all just completely dead. So that kind of cheesy stuff you can see in that little corner there is actually a dead bit of t um, a few more and these are basically where metalwork is exposed. So none of these look overtly infected. There's no pus, it's not particularly erythematous. Um, they have a bit of pain but not massive amount of pain. And all of these patients have been living with this exposed metal work for years actually. So how acutely and actively infected these are, you could argue, but there are definitely bugs there, right? This is definitely colonized with the outside world, with the staph aureus on the skin and it probably goes deep. Um But you can see that patients could live with this for quite a long time and sort of come to a happy relationship between the muscle work, the bugs and the rest of the body. So I've got a question here. Um I just need to go back to that if you want to stick an answer in the, in the chat. For me, the microbiology profile of a fact related infection depends on the time to presentation. You can shout out some answers or put them in the chat. So a couple of truths true. Uh and is, is that based on something you've heard or based on a paper you've read or the or the general vibe from the last Roma meeting you were at vibes. Yeah. The, the ways in which most of us, you know, our information experience Yeah, cool. All right. So, it, it probably doesn't matter quite as much as we think it does. Um, so I have a paper, this is being a bit irritating to show you back and forth. Um, so 22 papers that might be helpful. One is from Cameroon and one is from three European centers. So, paper on the left, the 246 infection cases, um, looked at early, delayed and late uh in terms of timing of presentation and it didn't actually matter whether they presented early, delayed or late what bugs there were. Um And then 433 F ri cases from three centers in Europe. And the study was published about a year and a half ago. Again, no difference between early delayed and late. So there's a kind of a historical idea that the timing matters, right? You think that if something presents early, it's got the easier friendly bugs and if it presents late, then the easy bugs have been spread out and you just end up with resistance. It's probably not as much the case as we think it is so early, delayed, late, probably shouldn't guide which antibiotics you give, it might guide what you do in terms of um surgery depending on how stable your fracture is, but it probably shouldn't guide what you're doing microbiology wise. Uh Other question for you guys. Serial C RP is good for monitoring infection. I've, I've, I've made it a binary one false. No. Y you probably know where I'm going with this. Yes, I mean false. Yeah. Somebody else thinks it is. I've left this deliberately vague in the context of somebody who's really septic on Itu and you haven't got much else to go on. Serial CRP s are probably helpful. So, septic itu, you're wanting to monitor the trend of something, you know, is it going from like 500 to 50 probably helpful in the context of bone and joint infection. Are CRP s helpful. No. Are CRPS useful to do for anything? No, do I do them? No. Do they cost money? Yes. Um So II don't personally get offended by somebody doing them, but they're just a bit of a waste of time and like, why would you do it? So if I have somebody with a hole in their leg that's hosing out pus in, what way does a CRP help me? It makes no difference, right? If it's a high CRP, I'm going to be like, yeah, you've got pus in your leg. If it's a low CRP, I'm still going to do something because they've still got pus in their leg. So serial crp not, not helpful. There are infectious diseases, doctors and microbiology, doctors who still like doing them. Some people like numbers for native bone and joint infection really not that helpful. There's a bit of uh slightly different literature for prosthetic joint infection. So if you have an arthroplasty surgeon who would like serial CRPS to decide when he's going to do a second stage. You probably don't need to argue at this point quite so much. But it, it doesn't really need to be part of your routine practice for um F ri. So there's a, there's a nice paper, a systematic review of inflammatory markers in general in F ri from 2018 and sensitivity and specificity really not helpful to either rule in or rule out F ri the blood tests. I do do so investigations wise for F ri blood tests that are helpful. Vitamin D everybody I see gets a Vitamin D and even if they have normal Vitamin D levels, they get supplements. But I think probably about 75% of my patients have a low Vitamin D So just give everybody Vitamin D um, thyroid function super helpful because hypothyroidism is a risk factor for non union. So all my patients get thyroid function also because they're all depressed. I just want to make sure they're not hypothyroid HBA one C to see how their diabetes is or do they have diabetes? A full blood count? Everybody gets to see what the white cells are and hematinics and a hemoglobin just to see their kind of general physiological state. Uh And then I do a set of blood tests uh to help if people are gonna go onto antibiotics, which many of them are. So, I do some baseline LFT S and baseline renal function and then I do viral serology. So, hepatitis BC and HIV for just the first time. So most of these, the other tests that I've listed there, I think are a good kind of baseline screening panel for anybody presenting with kind of complex nonunion but specifically also fracture related infection, imaging wise. What are helpful scans to do? Why would you do a scan? What kind of scan helps you? So, is there a fracture related infection? There are certain scans that would help. The other thing you might want is to visualize the anatomic details of the disease. So, where's the sequester? Is there a cloaca, where's the sinus tract starting and going to uh and then you also wanna know has the fracture healed uh and how stable is it? So, imaging wise, I've put there number one, number two and number three are always plain x rays. And if you have nothing else available to you, you can get a really long way in terms of making a management plan and treating a patient with just the x rays. So the x rays are going to tell you uh give you a good indication of his own infection. Has the bone healed? Is there a sequester? Uh is there a cloaca MRI scan is good for your surgical approach and also to know what the soft tissues are looking like. So that sinus tract you can see on the outside, where does it track down to into the femur? And the images I put here are all of the same femur. So same case, a CT scan is helpful to look at the sequester and then also to see whether the bone is healed and I hope you can see kind of midshaft of that femur. Um there's a, a gaping hole and then a sequester a dead bit of bone stuck right in the middle of it, nuclear medicine. The details of this I won't go into. But I think what's helpful to know is that a pet CT is probably the investigation, the highest sensitivity and specificity for looking at fracture related infection. It's not if you do a scan of a femur and you really don't know what's going on and you have some high signal, it's not going to tell you it's infection and it's not a tumor. But if you're pretty sure that it's an infection, it's going to tell you where the active bits of infection are. So for this particular case, he had a proximal neck of femur fracture. He had an entire diaphysis of the femur that was just an absolute mess. And then he had an ankylosed knee. You can see the patella is totally stuck to the distal femur. Ah how much of this did I need to excise and debride? What was actually the acute problem? And in actual fact, it was only a very small localized area that was directly at the site of the sinus and where that sequester was. So it meant that I didn't need to go up to proximal femur and I didn't need to ream out the entirety of the medullary canal and have to do bone transport and so on. So, just a, a few more X rays and kind of imaging things. Um I don't know if somebody wants to talk me through what they can see here. Actually, that might be helpful. Somebody wanna talk me through what they can see on that sequence of X rays. Yeah, sure. Um So we've got a series of radiological images at various stages of recovery from below knee amputation. So, on the left side, we've got an immediate POSTOP image x-ray image in the middle, we have uh another X ray image which um taken that at this stage. And on the right side, we've got an at two weighted fat, suppressed MRI scan. Um And what it seems to show is progressive erosion of the tibial stump. I can see the distal, the fibular stump was also there seems to be some, some lysis as well, but most but focusing mainly on the a tibia on the X ray image in the middle. You can see that there's a loss of, well, there's a lot of the, the normal, there's a, there's like I said, erosion of the, of the stump. You can see there's fragmentation of bone distally as well. There seems to be a bit more soft tissue swelling around the stump as well. And then looking at MRI scan, I can see there's lots of high signal within the distal tibia, lots of high signal within the soft tissues, possibly a sinus tract as well. But it's just going again, immediately distal to the stump. I can see there's periosteal, there's lifting of the periosteum on the medial side especially. So which could be and also a low signal lesion within the high signal, which could be evidence of a equestrian and and possibly an opening within the cortex cloaca as well. So, yeah, conclusion, this looks like a postoperative osteomyelitis of a stump of a below knee amputation. Yeah. Yeah. Good. So basically between that first image where you can see the surgical clips and then it might be just worth pointing out. Can you see that there are two little drill holes through the distal tibia? So somebody's probably done a myodes. So they've stitched stitched through tibia. Yeah. Yeah. Um And so basically between that X ray and the middle x-ray, this poor woman spent a year going backwards and forwards to the tissue viability nurses and district nurses with a discharging bit of sinus and little fragments of bone coming out. Um And it took a year before somebody decided to send her elsewhere and that probably, you know, there's a problem, but you can see that you've actually got most of the information from just that X ray. And the reason I did an MRI was just to see how far up the tibia, you know that there was edema or there was likely to be infection, but you can kind of see it pretty much from that X ray. Um, um, and it just shows you that kind of sequence of what the infection will do and what bugs will do in bone is they, they just destroy it, munch it away and you start out with kind of neat, clear lines of cortex and medullary canal and that's just all lost really. I mean, people talk about moth eaten, which it is a little bit, right? It looks like it's been nibbled at and you end up with these tiny little fragments. Um I put this one up because there's not very much to see on this X ray. But in actual fact, this was a young guy who injured his ankle playing rugby and they did this ankle fixation. You can critique the ankle fixation, but it's probably fine. But unfortunately, the lateral wound broke down at about the six week mark. And then they managed it in a fracture clinic for about six months with a big hole on the lateral side of his fibula. And they said it'll get better, it'll get better, it'll get better and it didn't get better because these things don't just go away by themselves. But it meant that by the time you got to see me bone was sufficiently healed that I was able to take out all of this metalwork. And then the plastic surgeons did a kind of propeller type flap to cover over the lateral defect. And his samples were five out of five staph aureus. Uh This again is that femur that I showed before. So you can see this was a chap from Kuwait in a road traffic collision about 15 years ago. So he had a proximal proximal femur fracture that I think they put a DHS type construct in and that had fairly well healed. And then he had, he had a nail in at some point, he had a kind of a monolateral fix on at some point. And then he's had this discharging sinus. Can you see on this lateral aspect of the mid shaft of the femur? Um there's a defect there and that's exactly where his sinus is. Um And then you can see all of this abnormal architecture in the midshaft ah with cloaca but also probably previous pin sites. And then this massive bone in here that you think is that healed? Is that not healed? What's estrum? What's involucre? And then as I pointed out before the patella is totally stuck to the distal femur. Um And then there's this MRI scan which is looking at that sinus tract and how that relates to the rest of the femur and the little sequestrum in the midshaft and then there's the pet CT, I haven't changed all the sequences, but you can see that the high uptake is just there in the midshaft of the femur. And that's exactly where her sinus tract is. Ah, it's worthwhile knowing that this is what a pet CT looks like. And I'm sure that you'll get other sessions on imaging. But I think bone infection is quite a nice sort of way to go through lots of different imaging modalities, particularly around nuclear medicine. A little bit on classification. And then I'll come to some management principles. So I think two classification systems that are useful for you to know about. And in um what's not common in orthopedics is that you actually have a classification system that's useful. But this one is so this is certainly major four stages in terms of anatomy and three different types of host in terms of physiology. So anatomic type is one is medullary. So there's infection just inside the medullary canal. Two is it's superficial only cortex is involved. Three is you have cortex plus medullary canal involved but not circumferentially. And four is diffuse. So you have cortex, medulla and cortex all the way on the other side as well. And this is a really helpful classification system because if you are dealing with stage one, you only really need to get infection rid of infection from the medullary canal. So you can ream out stages two and three, you can usually do a localized excision stage four, you start thinking about having to do a segmental resection and then the physiologic uh kind of status is A B and C. So A is a normal host. B, you either have systemic or local compromise and C the treatment is worse than the disease. So I think as far as classification systems go, it's user friendly, fairly straightforward and helpful to guide management. The other one that's a bit newer, but that maybe gives you a little bit less direction or steer in terms of how you manage. It is the bath classification. So this stands for B for bone involvement, A for your antimicrobial options, C for soft tissue coverage and H for host status. And you basically have three categories in the traffic light system. So green is uncomplicated, orange or amber is complex and red is limited options. And in each of those categories, what's nice about this is that it highlights how important all the different elements are. So bone, uh bugs, soft tissues and the patient and hot off the press literally just published this month is a new classification system specifically for fracture related infection. And it's called F ri. So F for fracture, R for relevant patient factors and I for impairment of soft tissues, they stretched the words a little bit, but that's, that's what it is. And you've got a similar sort of traffic light system. So two shades of green, A yellow and amber and a red 12345 that you can find this open access, encourage you to have a look. Highly unlikely that anybody at this stage is going to ask you about the detail of it. But helpful to know it's there ah two guidelines to or one guideline and one kind of consensus paper to know about. So there is an a boast F ri guideline. There's nothing groundbreaking in it. Nothing revolutionary. But if you get out of this in the exam, you need to be able to say it and the points are, it's patient centered. It's led by the MDT. It's delivered by specialist teams and you need to do a good job of the surgery. The overall kind of consensus group F ri guideline basically says the same thing patient centered led by an MDT delivered by specialist teams and you need to do good surgery. Uh Quick straw poll here, bone infection is a common orthopedic condition and everybody should manage it. A AB or C BC. Yeah, BC. Tom, you're like ABC, the whole the whole gang. Not sure any, any other takers falls. Yeah. False. Yeah. So my, my take on this is everybody should know how to manage a septic patient, right? Like the the point of being a doctor is everybody needs to manage a septic patient. If you don't know how to manage a septic patient, you know, you, you need to be able to manage that. I would strongly recommend that. Yes, bone infection is common but not everyone should manage it. So, bone infection like sarcoma like a complex periprosthetic fracture. Don't just have a go, don't just think, you know, my pride's at stake. I need to do something about this. Most fracture related infection can wait. It can definitely wait until the following morning when you can Google or pick up the phone or find a friend who knows what to do. So, the only scenario in which you need to be gung ho about this or feel like your pride is at stake and do something is middle of the night. You have somebody septic otherwise, phone a friend, find out where your MDT is, make sure it gets done well. This is not just for anybody and everybody to have a go at, ah, quite good evidence emerging for that. It's not just because some of us really love it and we want to get to do all of it. People do do better when they're managed well and it's because you need the multidisciplinary team. Bone infection is not an orthopedic condition. Bone infection is an orthopedic slash plastics slash psychology slash physio slash micro slash ID problem. You really need everybody on board if you're going to manage this well, you cannot deliver good fracture related infection care. If you are a sole orthopod, there's a good paper from a surgeon called Marcus Roop who looked at this and basically, if you were managed in an appropriate MDT process, you were significantly less likely to have an amputation and significantly less likely to have a revision surgery. Also lower rates, less, not statistically significant but lower rates of antibiotic use, lower, less, less debridement, lower rates of recurrence and less treatment failures. Uh So there's no scenario in which I think you can justify managing a bone infection if you're not doing it in an MDT set up the point about specialist centers also 100%. The right way to go is to do this in a center that has experience in managing bone infection. So this was a paper from Oxford from a little while ago. And they basically compared their bone infection unit compared to the rest of England and they compared to the rest of England. But then they also compared to the next, the 10 next busiest centers based on Osteomyelitis treatment. And they used the HS database for that and looked at about 25,000 patients. Basically, if you were managed in a bone infection unit. So MDT, yes, but specialist MDT, there were fewer trips to theater lower mortality and your amputation rate was lower. I think if you were a patient and you had that information available to you, you would really strongly advocate for being managed in a specialist center by an appropriate MDT. So management principles, post optimization. You need good biology. You need good blood supply. You need the patient's head to be in the game and you need to make sure that they don't lose function. And I'm a really strong advocate of the kind of rehabilitation. Make sure patients keep moving. Preop biology. The main thing is make sure the Vitamin D and the thyroid are ok. Blood supply, revascularize them pre op if you need to make sure the plastic surgeons are aggressive with how they manage the soft tissues. Two main ways you can manage fracture related infection. You can either intervene operatively or not non operatively. Pretty much like anything in orthopedics indications for no surgery. Patients coping fine with the symptoms are like doc, I've had this for 15 years. I'm kind of ok. I don't want what you're proposing. Totally fine patients who unwell for surgery. They're 95 they've got an echo feur fracture. They're 95. They have dementia. You know, you do not have to operate on any everybody with a fracture related infection. For some people. The treatment may be worse than the disease for some people. They may need a segment resection leading to, you know, a year or two in a frame with bone transport. And they're just like, I'm not up for that surgical thing is the only thing that's really going to fully eradicate the disease. I say cure the disease because there is an argument that you never all the way, get rid of it. Um But if you really want the bugs gone and there to be no infection, you need to do surgery, but you have to have the patient fully on board and they need to know that no surgery is an option and it needs to be done in the right sort of space. This is a kind of a typical patient pathway just to put it out there that it's helpful for everybody to have a kind of a structure of how you go through and assess people and get them ready for surgery. Antibiotics wise, you can have local antibiotics or systemic antibiotics. I'd really strongly urge you to use the right nomenclature when you're talking about local antibiotics. So the way to do this is to talk about bone cement and then to talk about antibiotic carriers. So antibiotic carriers include things like Samant and Stimulan. I'd avoid using those kind of industry terms and stuff. I think it's much better to just say antibiotic carriers and antibiotic carriers are of different types and will have different antibiotics in them and they are separate and they are different from bone cement. They have different drug elution profiles. Your systemic antibiotics may be oral or intravenous. And I think if you can use this language to talk about how you treat bone infection, it demonstrates that you kind of know what you're talking about. The two really important clinical trials to be aware of here are viva and Adam Brookes was involved in that study. So, you know, worth knowing about an OVI A looked at oral versus intravenous antibiotics and that demonstrated that oral antibiotics were non inferior to intravenous. So the only scenario really in which you need intravenous antibiotics are if patients not tolerating the oral option or you have significant resistance to the oral options available to you. The other study to know about is the salario trial and the solar trial has compared standard regimen of local antibiotics with six weeks of systemic versus just the standard regimen of local antibiotics and a 24 to 48 hour period of systemic antibiotics. And the results of that will be announced more fully at the European Mo Infection Society meeting in two weeks time upshot of the antibiotics is know what your local guidelines are. Work with your infectious diseases and micro team. And once you've decided what you're doing, stay the course for that and do do that treatment. So whatever treatment duration you're doing and whether you're going systemic or local or both surgical management. What are your aims again? From one of the consensus papers, a really kind of nice drop, drop down list and maybe just think about that case that Dr Nickerson presented with the tibial nail and the medial wound defect. What are your aims? What do you want to achieve with surgical management? So you want the fracture to heal, you want the infection to be gone, you want the soft tissues to be healed, you want function to be restored and you want to prevent recurrence. You don't want anything, you don't want that infection to come back. And there's a really nice kind of flow diagram of this. So first patient contact diagnostic workup, suspected or confirmed F ri uh and then host status and host optimization. We've already talked about host optimization, you then work your way through. So then it's got a a section which is on hospitalization. Um And it's all about the MDT approach and then follow up should be for a minimum of 12 months. And I follow all of my patients up uh until the two year mark aims of surgery we've discussed already and then your surgical options. So I like to think of this as a kind of, you know, much the same way that the plastic surgeons have that kind of stepwise approach. The analgesic ladder is all about a stepwise approach. I think for fracture related infection, you can also think about that step wise approach. What do I need to do here? What kind of F ri am I dealing with? What kind of patient am I dealing with? Your kind of basic standard would be to do a wash out patient septic. There's pus hazing out, drop the BP, you need to just reduce the infection burden, you need to get rid of the pus, you can do a washout, not touch any of the metal work, not do anything else. Very aggressive. Next step up from that would be a dare. So dare is appropriate and fracture related infection, particularly if you want to try and get the bone to heal, you do not need to remove all infected me work. There are scenarios in which it's perfectly acceptable to open stuff up sample, assess the stability of your implants, uh put in some local antibiotics, close it all up again and wait for the bone to heal and take out the matter work at a later stage. That is an acceptable course of treatment. You may then want to do the next step up from that which is bone is healed. You wanna get rid of the muscle work, you sample your debride and you put in your local antibiotics. Segmental resection is really for that certainly major type four where you've got whole bone involvement, the whole thing is dead. There's nothing you can do with it. And that's when you're dealing with a segmental resection. But that's really the last resort and really be mindful that if you're looking at a segmental resection, you're looking at committing that patient to bone transport, which is quite a major undertaking. These are the the the really as a broad principle surgical steps. So make your incision usually around the sinus and you want to excise that sinus. If that sinus has been present for more than 12 months, do send it away for histology because you can get malignant transformation, you then focus on sampling. So ignore everything else. Do not think about debridement. Do not think about the fracture. Purely, purely focus on getting five good samples that are not contaminated. You then focus on debridement and go sequentially. I go clockwise and anticlockwise and then clockwise again. Wash it all out. It doesn't matter what you wash it with. There's no evidence that one thing is better than another, but you use lots and lots of it put in your local antibiotic carrier, whatever it is that you're going to use then assess the stability. And my rule of thumb is that I want that patient to be able to walk on that lower limb. Once I finished, if I feel like I've debrided so much that I've left the bone that unstable or that weak that if they put weight on it, it's going to break, then I put on a simple monolateral frame and then you want to close the wound. And the really important thing about wound closure is it's not just about wound closure, but it's about good soft tissue cover and good blood supply. Um It, you want to close the dead space. You want to make sure that you've got all the best blood supply possible. Going to that question on sampling. I'm hoping some, it might be one person, maybe two. Got the right answer here. How, how many samples? Yeah, I haven't got the right answer yet. Oh, yeah, tiny, well done. Uh So the answer is d so any less than any fewer than five, And you will miss something. So fewer than five, you will miss a significant proportion of the infections any more than five. And you're basically costing the NHS money for no additional benefit. So that's why uh C is not a correct answer because sending more than five is it, it's costing the NHS money without any additional benefit. So five is what you want to send. Uh And the evidence for that is this paper, um Big cohort looked at all of their sampling basically. Uh And so if you had two out of five specimens with indistinguishable microorganisms, er, that was 68% sensitive and 87% specific for the diagnosis of F RI I've put those figures in there because it's clearly not an amazing diagnostic test, right? 68% sensitive. You're still missing a lot of cases. Um But that's the kind of sweet spot is the five samples. That's where I've left it at. Um Because I think, well, I've used about an hour but because I thought it might be nice to just go back. I don't think we do. We have Dr Nickerson's slides, Dale Se just to go back to that tibia case. I don't think she sent them across to me. Unfortunately, things you had a question there. Yes. Histology. Yes. Very good. Yes, definitely. Send one or two for histology and on histology. Kind of need to have a pathologist who's on board with it. So, if you send a histology sample from an infection case to just a general blood standard pathologist, they'll be like, why did you send this to me? This is not cancer. That's all I can say. So, you kind of need to have a pathologist who's on board with this and knows what they're looking at. And the specific test that they should really be looking for is the polymorph in nuclear sites and it's five per high powered field. Um So yes, good practice is to send it for Histo as well. And as I said, the sinus never send the sinus for micro. That's a complete and utter waste of time. Bad thing to do. Never send the sinus from micro. But if it's been there for more than 12 months, send the sinus for histo. So is that just, are you, are you send the five micro and then one additional tissue sample for histology or do they? Is it just the five in total? So five micro one histo. Yeah. And the important thing kind of the important thing about the five micro is that there's a particular way that you sample. It's a bit hard to kind of talk this through in a lecture format. I usually run a workshop on it. But the point about the five samples is that each sample is taken with a separate set of instruments that are totally clean and the sample goes from your forceps. So, a clean forceps, it's never been used on anything else before. It hasn't touched the skin. It goes straight into the part. It doesn't go on a swab first. You don't give it to the scrub nurse, it goes straight into your specimen part and the lid gets put on and then for your next sample, you do completely separate set of instruments, separate part. Because as soon as you've got cross contamination, your diagnostic certainty is gone, right? Because then all you've done basically is you've just got the bugs from one that have gone into the other pot because you need two out of five to be positive. Um, blood culture bottles. Good question. Yes, you can do blood culture bottles in my trust. If I just send the normal, they then put it onto an appropriate medium. So they've got their own algorithm for how they do it. So it depends a little bit on what your lab is like where your lab is. The really important thing about the conversation between you sampling and the lab is the time that it takes between you sampling and it arriving in the lab. So the longer a sample takes to leave theaters basically and get to the lab, much less likely you are to get a positive result back. Basically. Bugs love it when it's dark. And it's a bit warm and it's a bit mucky and they've got food to eat. So, basically, like the bench on the side of theater where it's super bright, freezing cold and there's nothing for them to do except for sitting in a pot that's empty. They die. They hate it. And so my samples, the minute I finish taking my samples, the porter comes and they go straight to the lab. So the quick, the quicker you can get them onto the petro dish or on the blood culture bottles, the better Liz. Sorry, I just had a quick question. Thank you very much for that. Um Just wondered about, you know, with des so when I was reading about PJ ISA while back, um then they talk about 3 to 4 weeks being the window before biofilm forms and therefore de being an appropriate management option of your peri implants or your fracture related infections. Is it a very similar concept that you would only really consider a dare up to kind of that four week mark? Or is it not really because clinically I've seen it's very different. So although you read about this 3 to 4 week mark, I've seen bosses doing dares beyond that period of time. So I think doing a dare beyond the 3 to 4 weeks is OK. So there's a good paper from a group in the Netherlands and they looked at their dare cases and they, they went way beyond that because really you want that bone to heal, right? If you take everything out and the bone hasn't healed, then you're like you're in a real pickle. So there's no harm in waiting a bit longer. There is a difference in dares between plate screw fixation and intramedullary nails. So if you do a dare on plate and screws, you can kind of really scrub the lateral aspect of the plate or the plate. You know, the bit of the plate you see, you can swap out screws, you can do a pretty good clean up and you can put in quite a lot of local antibiotic delivery with an intramedullary nail, you cannot do a good debridement in any shape or form with that nail still in, right? Because the entire intramedullary space and nail are covered in bugs. So you do not have the same option for debridement or for intramedullary antibiotic delivery. So dares in intramedullary nails are less successful. And do you ever deliver anything out? A nail is probably a better option than persisting with the same nail. But keeping a distal tibia complex peel on to go in and take every last bit of screw out, you're just going to end up with a mess. You can do a pretty good debridement of that and do some good local antibiotic delivery and keep your stability. Ok, fine. So for nails usually exchange them out, but obviously for your plates, give them a really good scrub change the re and that tends to be ok. And in terms of period of time, so, you know, when you talk about a kind of period, um like of time from the infection, I know that PGI, there's various things that ok, you look at when the operation happened, but then you also look at when their symptoms began, et cetera. Yeah. So with this, because obviously when we talk about fracture related infection, we're talking about fracture. That could be 345 years previously. Yeah. And then now they've got infective symptoms. Yeah. Is it mainly from when the symptomology starts or when the wound looks broken down or when you're talking about the timing? Do you talk about it from that? From the change in picture or do you talk about? Yeah, you took for timing like on the early, delayed, early, delayed, late. It's from when, when the clinical picture changes. Yeah. Fine. Yeah. OK. It's the same thing. All right. That's great. Thank you. Yeah. So just come coming back to that ne coming back to that nail case. So we've got an intramedullary nail. We've got a broken, we've got a a hole basically on the medial side. Doctor Nickerson's case. Yeah. Would you guys having now heard about surgical principles and so on? Would you guys revise how you would manage that? Is there anything you do differently? And is there perhaps language that you might use? That's different? I just, I don't know whether in that case, I would remove the nail, do some sort of rear to do some uh local antibiotic delivery to the tibia and then do an exchange now because stability is obviously important in order to achieve um kind of curative intent with infection and allow for bone healing. Yeah. Um And then obviously, what words can you use there that are a bit more around the principles. Um So debride that we want to do debridement antibiotic. Um So you could, but it's like doing a dare basically. So we'd be doing a debridement antibiotic uh delivery um and implant retention or in this case, exchange um to allow for stability and um local antibiotic delivery. Yeah. So when you're talking about the antibiotics, it's nice to use the phrase I would do local and systemic antibiotics, you know, in, in consultation with my local guidelines and my micro team, there are a few of you who talked about putting an X fix on that tibia. And I just wanted to come back to that. I didn't uh I don't know if she showed an X ray of what the tibia looked like. Was, was there an X ray? Regardless of I'm imagining it sort of dis the junction of middle and distal thirds of a tibia. How, how much stability are you gonna get of a tibia with an X fix? It depends on what kind of X fix you're putting on the legs. If you're doing a standard frame, not tons. But if you put a hex pod on, sorry, a circular frame on, you can get plenty of. But I think if you're mentioning external fixation or most people or ex fix, most people will be thinking you're doing a kind of a trauma type scenario, ex fix. So you probably, and the menc that would be better to use would be to stabilize it and you probably need a circular frame. So anything monolateral on a tibia like that, that hasn't healed anywhere on the shaft. Really, it's going to flop all over the place that's never going to heal, that doesn't provide enough stability. So if you take that nail out, so take the nail out sample to bride, put on an X fix and then they do a free flap, you're still going to get a lot of movement and it's going to struggle to heal. So really be thinking about either exchange nailing it. So putting in a fresh nail with local antibiotics, which is a reasonable thing to do if you're happy with your debridement or think about a circular frame, but an AFI is not going to cut it. An X fix is not going to give you the stability you need for it to heal. Also, if it was a bit sticky and if you had a reasonable callus at the fracture site, by the time you've gone in, reamed it up and debrided. It all of that's gone, right? That stickiness is gone. So it's literally just gonna do this. Um So, so, yeah. Yeah. My, my only concern with doing the exchange nailing was the, the soft tissue defect. So free flap. And I'd really strongly advocate for single stage surgery if you have your MDT set up in such a way that you can do single stage surgery. It's really the best thing. So what you don't want to do in a scenario like this is sample a bride put on an X fix. And then like a week later, the plastic surgeons come and put a free flap on it because in that intervening time, it's been colonized by all new bugs. So in an ideal scenario like that, I would advocate for taking out that nail sample it really well, ream it flush it all through, put in a new nail with lots of antibiotics around it, get the surgeons to do a really nice free flap and then you're done, it'll heal. Uh Unless, unless there's something else major, you know, catastrophic gone gone wrong. Um Oh, somebody mentioned ra personal preference. I think ra is a complete and utter waste of money. It's an absolute faff for the scrub nurses. It's af for the surgeon. You don't, you don't get a feel for what your debridements like. If you just use some flexible reamers, they're great for sampling because you can just use it when you go in next one up on the Reamer, you've got to clean bit of reamer that goes down, you sample from that, you get a feel for what's coming out. So when you're doing an intramedullary debridement, you really need to get a feel for. I've, I've scraped out every last bit of the inner cortex of that medullary canal. I've taken out all the biofilm, slimy stuff and I'm now on the healthy cancellus bone. If you're rear in that, you have no idea what's going on in that intramedullary space. It's just like this massive thing going in that. Um And then what you wanna do is you wanna flush it through. So in this case, flush from the top and see the fluid come out at the bottom and once the fluid at the bottom comes out with no debris in it, then you can satisfy yourself that you've done a decent wash out. So, yeah, I it's a personal preference. There are some people who love the ra thing. I think it's not bad if you want graft. But um yeah, I don't love it. You just have a quick question about you. Whoever wants to, I was just going to go back on that. So that single stage surgery, would you still do that in an acute infective setting? You can do? Yeah, I mean, if the patient is really septic and it looks like they've got liters of pus in their tibia, then be a bit mindful but, you know, that one's a pretty indolent sort of, you know, it's probably a bit of a staph aureus in there. You know, I think it's not unreasonable in that setting to do also. You don't need the infection to be all the way gone. You just need the patient's immune system and the blood supply and the biology to be good enough to get that to heal so that you can then take the nail out completely. Yeah, but just in terms of the plastic, putting a flap on it as well, concerns about the infection, but they're happy experience. Yeah, it really depends on your plastic surgeon, how well you work together. And that's why the MDT process is really important. So, you know, you need to have plastic surgeons who you have confidence, they have confidence in you. You know, they need to be happy that when you say you debrided it and cleared it all out and filled it all up with antibiotics, that it's going to be fine for their free flap. Um And you need to have confidence that if the free flap breaks down, they're not gonna blame you every time when it comes to exchange nailing local antibiotic delivery. Is that just a case of just packing the canal with your um with your antibiotic carrier and then put it in the n after that. Um So what I tend to do for the intramedullary nails, I use cement with either Gentamicin or Vancomycin. And you can basically fill up the canal. It comes, if you go relatively early with it, it's still quite liquid. So you can basically fill up the canal with that and then put your nail in and then you can squirt more through, through the top. You need to be a bit mindful around the tibia. You don't get it in the joint depending on where your entry is. Um But then you've got basically it, then the liquid sort of pulls down by gravity and then as the nail goes in, it spreads all spreads all along the nail and then it'll go, it'll go solid at about 20 minutes or so. Um You can also fill it up with stimulant, but then obviously, it's very hard to get your nail in. So you could put the nail in and then put some stimulant, uh less, less useful. Um There are people who do cement coated nails, but your drug elution profile and a cement coated nail is not as good as the drug elution profile of something like cement. When it comes to locking the nail, is it threshold, is it threshold? Trying to make that threshold would be better? Because then you, you've got more purchase in it, right if you just put the screw. But what you do need to do is over drill all the screw holes. So it's not just about reaming and from au but you need to overdrill all the screw holes. So you take a separate drill and you drill wider diameter than the screw that you took out and over drill into the drill holes. Ok? Um And then what's quite helpful is you can fill those up with salmon. So if you take the short nozzle, you just put your short nozzle and fill up the screw holes with salmon. And those will give you a little bit of extra stability, slightly less likely to break through that in any other questions, guys. Hopefully, some of that's useful for real life. Some of it may come up in the exam. I suspect that more of it will come up in the exam in like 10 years from now, once the examiners catch up with an evolving bit of orthopedics. Um but yeah, useful. Hopefully for a bit of real life and a general orthopedic uncle. That's awesome. Thanks.