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Back to Basics: Orthopaedics 101 - Session 1: Introduction to Fractures and Biology of Bone Healing



This on-demand teaching session introduces medical professionals to fractures, including the causes, how to describe a fracture, different configurations of fractures, and how to comprehend fractures in pediatric patients. Get informed on this essential topic to be able to better diagnose and treat those with bone injuries, by attending this insightful session.
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Series of Orthopaedic lectures and interactive teaching sessions directed at tier 1 level. Delivered by a mix of consultants and registrars, this series of teaching aims to cover the basics of Orthopaedics, including spinal and paediatric cases. Excellent for those who are orthopaedically minded, those studying for the MRCS or have an upcoming Orthopaedic job!

1st session of the Back to Basics: Orthopaedics 101 series. We will discuss the various fracture patterns, and how to accurately describe a fracture. Moreover, we will cover the biology of bone healing which provides the foundation of surgical management planning and implant choice.

The first half on Introduction to Fractures will be given by Mr Kareem Edres (ST4, East of England Rotation) and the second half will be on 'Biology on Bone Healing and Non Unions' by Mr Sebastian Ho (ST4, East of England Rotation)

This session will be recorded, it is interactive, by joining this session you are agreeing that your name, your voice and your image can be included in the recording.

Learning objectives

Learning Objectives 1. Identify the main types of fractures: direct violence, indirect violence, fatigue, and pathological fractures 2. Describe the properties of a transverse, oblique, and spiral fractures 3. Elaborate on the benefits of the periosteum in terms of providing nutrition and protection for pediatric patients 4. Explain how to accurately describe the configuration and location of a fracture using medical terminology 5. Recognize the signs of a greenstick and buccal fracture on an X-ray
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Computer generated transcript

The following transcript was generated automatically from the content and has not been checked or corrected manually.

This is going to be introduction to fractures. I've already introduced myself. So what is a fracture? Ok. A fracture is defined as any loss of continuity in the substance of a bone. So if the bone is, if there is just a hairline fracture, microscopic fracture, something you can only see on an MRI or whether the bone is 1000 pieces, multi fragmentary fractures, it's still broken. Ok. Some patients will ask you, is it broken or is it fractured? There's no difference, it's broken, it's fractured, it's post, it's all the same thing. It's just a loss of continuity in the substance of a bone, any bone. Ok. So what are the causes of fractures? Causes of fractures vary and the amount of energy required to cause a fracture varies as well. So causes of a fracture can be due to direct violence. So this type of direct violence with a stick, uh for example, straight to the arm is usually uh one of the main causes of ulnar fractures. It's called a night stick fracture because police officers carrying their night sticks, attacking, you know, a civilian or you know, a criminal depending on uh where in the world, the police is can uh uh cause ulna fractures. Mainly these are called nightstick fractures. Now you can get indirect violence. So you can get a little old lady who has a fall to the ground from standing, right and sustains a hip fracture. Or you can get somebody who's young and fit skiing or skateboarding, for example, twist their ankle, the twisting injuries, indirect violence, but it causes a fracture. Nonetheless, in some cases, you can get fatigue fractures fractures where you have, for example, uh like in the previous slide, you can have a marching soldier. Um So soldiers do a lot of marching and that continuous stress on the bones of the foot can result in these hairline fractures that are very subtle, very difficult to appreciate on an x-ray but usually present much later with pain. And you can see the surrounding callus as you can see in this picture here. So I don't know if you can see my cursor, but it's that area that bulge is sort of bone growth around the second metatarsal there that's cause a stress fracture. Other people who might get this fracture other than soldiers, you can see in lot in, in runners, you can see in uh dancers as well. The lead dancers are quite known for getting stress fractures too. You can get pathological fractures and patho pathological fractures are not necessarily due to cancer. So you can get pathological fracture because of hypoparathyroidism or because of bisphosphonates. Uh but most commonly due to uh cancerous lesions. So, there are specific types of cancer that are well known to uh metastasize in bone. And these are the brain, the thyroid, the breast, the uh uh renal glands and the prostate as well. And these are well known to metastasize uh sorry, the, the kidney, not the renal glands, the kidneys and the prostate are well known to metastasize in bone and cause pathological fractures. OK. Pathological fractures can be it can, it can be like this one. You see here where there's a lit lesion. Li th lesion means there's loss of bone substance or they can be the sclerosis and sclerosis is uh where you have more bone growth but the bone becomes very brittle and can break like a dry twig. OK. So how to describe a fracture? OK. And the reason I have this picture here is not for diversity. This picture is here because uh you're going to be sending messages to your senior, to your consultant and you're going to be letting them know why uh that about a certain fracture. Sometimes you won't be able to send the x-rays that you know whatsapp makes that life a lot easier and you can send just patient x-rays. But having the skill of describing a fracture over the phone to your consultant in a registrar is a very valuable one. OK. So there are certain terms that you're going to have to use. And there are certain things that you're going to have to appreciate looking at x-rays in order to be able to describe a fracture correctly. Ok. So first off, you need to describe the configuration of the fracture, of course, after mentioning which bone is broken. OK. So you say this is a fracture, for example of the tibia, in this case, this is a transverse fracture. It's pretty self-explanatory, it's just a flat fracture. And the problem with these is that there's very limited surface area for the bones to heal. So if you can imagine breaking a pen exactly flat like that, putting the be toge the pen together will be difficult because you will not be able to appreciate where every piece fits. But for example, if you look at more of a an oblique fracture like this one, just because you have those spikes and that angulation, you'll be able to better appreciate the angle of the fracture and how to correctly reduce it or put it back together. Ok. The other problem with transverse fractures is that they are less likely to heal or heal well. And that's because you have less of a surface area for the bones to bond and to heal again. While an oblique fracture or in a spiral fracture, you have a lot more of an area for the bones to bond together and heal again. Spiral fractures are again very, the names are very self-explanatory, but it's a fracture that spirals around the bone, usually due to a twisting injury. And it's important that if you see a spiral fracture, that you assess the joint above or below, depending on the direction of the fracture. If there's an extension of this fracture further down and whether it's extending into the joint. In this case, for example, for those of you with more orthopedic experience, it's a femur fracture, nailing this fracture might be a little bit difficult if there's a, if, if there is an extension of the fracture into the joint, so it's always good when you're getting x-rays to assess the joint above and the joint below in the imaging. And also to keep in mind that a spiral fracture could cause an extension into the joint. There are avulsion fractures. An avulsion fracture is a fracture where a structure like a tendon or a ligament is attached to a bit of bone. So when somebody, for example, in this case, bends their knees quite severely or twist their knee quite severely, they will have an instance of something. Something basically we have to give, it will either be the ligament or the tendon or it's going to be the bone. It will really depend on which one is stronger. In this case, the ligament here, the medial collateral ligament was stronger than the bone. And so this chunk of bone came off of the medial aspect of the distal femur and then there are wedge fractures, wedge fractures are compression fractures. Basically. Imagine if you're, if you have a can and you squish it, that's exactly what it looks like. It's a compression fracture. You will have the surface a side of it that's be more compressed than the other side. This is what they look like. They're spinal fractures, mainly. Now in pediatric patients, there's a little bit of a variation and the reason for that is pediatric patients have incredible healing potential. They are growing. And so because they're growing, they have all the cells they need and all the nutrition they need for them to heal. And that all comes from the periosteum. The periosteum is the uh layer uh of tissue that is directly surrounding the bone, supplying it with blood vessel, uh with vascularity with the progenitor cells of osteoblasts and osteoclasts that are required for bone formation. And so even though some of you will know that the physis of the bone is where the bone grows longitudinally. The periosteum is what lays bone for circumferential growth. Ok. And so the periosteum is very important from that point of view, from the growth and nutrition, but also it acts as a sheath and a shield for bone when it's uh when it's under stress because pediatric bone is quite fragile and it's quite bendy. The periosteum surrounds it acts as a a protective sheath. And so you will see these sort of sorry, you can see these images where you have an incomplete fracture and you have a kink in the bone. OK. The image on the left, the lateral view of the forearm there, this is a fracture of the right, sorry again, this is a fracture of the radius and this is called a greenstick fracture. Like the green, like the greens sticks you have at parties. For example, this is basically the same concept. You have something that's within an outer rough layer, that uh tough layer that keeps it in shape. But the inner layer can be broken within with the shape more or less maintained. This is what it is. So uh the reason the snicker bars photo is there is that you can easily replicate that fracture with a snickers bar, you break one side and you can still maintain the opposite side or the opposite cortex of bone in position or un unbroken because it has that malleability to it in uh the image on the right that what we can see is this protrusion of bone either side of the broken radius and to a lesser extent here in the broken ulna. And this is called the buccal fracture. A buccal fracture is where you have longitudinal compression along the bone and basically the bone buckles into itself compresses into itself without completely fracturing. And again, that's because of the malleability of the bone in pediatric patients. The beauty of it is even if you leave these fractures as they are, they will heal. So, buccal fractures in uh in our hospital are treated conservatively sometimes with a splint, sometimes with just a little bit of a bulky bandage on the image on the left side, the greenstick fracture. Recent studies show that these fractures would remodel well, depending on the age of the pediatric patient, of course, but up to a certain age, if you leave a fracture with this angulation, it will heal and it will remodel into the normal shape of the bone over time. And so pediatric patients and pediatric fractures are a lot more forgiving. Now, the next thing is to describe the location of the fracture. So you've described the, you said which bone, you've described the configuration of the fracture, whether transverse oblique spiral wedge, avulsion, greenstick buccal. And then you're going to describe the location of the fracture. So these images are of a tibial plateau and a tibial plateau is the joint, ok. The joint surface of the tibia, proximal tibia which articulates with the distal femur. And in this joint, you can uh so fractures in the joint are called intraarticular fractures, fractures within the joint. OK? Or they can be fractures outside of the joint. So you can describe the fracture as a proximal fracture. It can be a junction, proximal third, middle third fracture. It can be a mid-shaft fracture, can be a junction, middle third, distal third fracture or it can be distal fracture. It's all very simple. It's all very self-explanatory, but it's basically the jargon or the lingo that you need to learn in order to be able to communicate with orthopedic surgeons. The other ways to describe the same thing is a proximal fracture or proximal epiphysis. Ok. So that's the area proximal to the EIS. It can be the metastasis, which is the transitional zone between the joint area and between the main shaft of the bone. It can be the diaphysis, which is the main shaft of the bone. So when somebody says metaphyseal fracture, you know, it's in that transitional area. When somebody says it's a diaphyseal fracture, you know, it's the shaft of the bone is what they mean and distally, it will be medaphis again because you have another transitional area where you extend into the distal if or the joint surface of the bone. Next thing you need to describe after you describe configuration and location is the overlying soft tissue. So you can get these gory fractures where you have basically all of the tibia coming out of the of the skin sometimes unbroken. So in this case, I don't think she's, I don't think this fracture is even uh um sorry, I don't think the tibia is even broken. Uh Everything seems to be intact, it just seems to be broken skin, but this will be an open fracture, dislocation of the ankle or you can have threatened skin where you have basically the bone edges. You can see there on the right hand side, almost puncturing through the skin. And this is an indication for quick intervention in order to protect the skin and avoid the injury, uh progressing into an open fracture from a closed fracture. Ok? And then you have the simple closed fractures where you don't have any threatened skin. You don't have any wounds overlying the fracture. And the difficult part is describing the displacement. OK. Displacement is basically any malalignment of the bone. If you can see a fracture on the x-ray, it means it's displaced. So you can't strictly speaking, observe a fracture on x-ray and say that this is a nondisplaced fracture. It can be a minimally displaced fracture. But if it hasn't moved at all, you would not be able to see it on an x-ray. You can spot it on an MRI scan, for example, with the surrounding edema as well where you would not be able to spot an undisplaced fracture. Strictly speaking on x-ray. OK. So in this uh in these x-rays, even though the A P can be misleading to the untrained eye, you can say that, oh, this is mostly undisplaced. But if you look on the lateral view, you can see that it's a very displaced fracture and very displaced to the point where we call it offended, the bone ends are not in contact with each other. This is an offended fracture, offended fractures are an indication for quick intervention mainly a manipulation in the emergency department to try to get the alignment back. A, to protect the neurovascular structures surrounding the fractured area. B to protect the skin and the soft tissues surrounding the fracture and C to prevent any contracture in the muscles that will be inadvertently caused. If you leave the fracture as it is because you will need that length and you will need the relaxation in the muscles and the ligaments in order to be able to reduce the fracture later on, when you take the patient to theater, when you're doing your definitive fixation. So how do you describe the deformity or how do you describe the displacement? OK. Now, there are three parameters to describe the deformity. It's one of the first one is translation. So translation means has the fracture moved medially or laterally. Now, the best way to judge it and the way it's commonly judged, the way we communicate is by describing how the distal fragment has gone. So your focus is mainly on the distal fragment of the fracture rather than the proximal fragment. And that way we all have the same sort of point of reference to discuss. So when you're looking at the at this image, you're going to describe the translation of the distal tibia and the foot. OK. Relative to the proximal fragment of the tibia because we cannot see a fibular fracture, everything seems to have translated laterally. OK. Thera the distal fragment of the tibia is moving towards the fibula which is in by definition, lateral to the tibia. OK. And it's all moving in this direction. So this is translation, it's the lateral or medial movement of the distal fragment. Next, you have angulation. OK. An angulation can be described in different ways. And that's this is why it's always very tricky because the point of reference is different, people can be different. And that's why the best way to describe it is to give the point of reference up front by saying the word apex. OK. So the apex of the fracture is basically the point of angulation. This here is the apex of the fracture where it forms this open sort of. Uh and the way I was started basically is the crocodile mouth is the when it was open, that's the apex. OK. So the apex of the fracture here is angulating right laterally. OK. So this is a laterally angulated fracture of the femur apex lateral. Next, you have rotation. So when you look at a fracture, you have to also describe whether it's rotated medially, whether it's rotated laterally relative to the bone. So translation is one plane angulation is the other plane rotation is the third plane of describing a deformity. OK. So this is an externally rotated foot relative to the to the ankle, relative to the rest of the leg. That's it. I'm happy to answer any questions guys or clarify anything. So please let me know your questions in the chat. I don't know if, uh, there's one question at the moment from Doctor Addy he's asking in the absence of reported trauma, would alkaline phosphatase among those with risk factors? Of course, you'd investigate for pathological fractures, especially in those with neuropathies. Um, good question. The answer to that question is, I don't really know. I'm not going to lie. I don't routinely look at alkaline phosphatase in uh in, in uh in patients, if the patient has no trauma and suspected a fracture, regardless of the alkaline phosphatase, I would have a lower threshold for investigating for pathological fractures. So say, for example, recently, we've had a case of a patient who without any trauma, had a, a subtrochanteric fracture of the femur, which is a very common zone of fractures around the femur. In the case of pathology. In this case, you'd start investigating straight away, you'd get the, the tests that are required including the alkaline phosphatase. But also you'd get an MRI scan of the femur to see if there's any sort of pathology there. If that's there, then you investigate them further with the chest, chest uh with a CT chest abdo pelvis and further tests to try to find the primary or identify whether this is the cause other investigations you can do intraoperatively. For example, is is biopsies of the lesion itself. But there's always clever people from our point of view that can help us that can help guide us from a laboratory perspective regarding these, uh, investigations. Yeah. I mean, I'd probably agree with that. An ALP by itself is not gonna tell you it's pathological or not. You have to look at the patient as a, as a whole really. Um, and you've got to look at the different factors. So, your history, your examination are all going to play important roles and then you're going to look at the rest of the patient. Is it just that area um that has this a lesion or is there somewhere else that they have got um you know, more widespread diffuse pathology going on? So you can't take it as just an isolated test. It's definitely gonna prompt you towards one way or the other. Um And remember in your history, you're also going to consider whether, you know, if they're having, if they've got an unusual fracture pattern. Have they been having pain in that for a prolonged period of time first? Because that might point you towards something pathological and it's been, you know, waving on that border of snapping any second until this most recent injury and then they had an a traumatic injury leading to the pathological fracture. So, er um yeah, I mean, even with, yeah. And then, so um next question is um was that translation example, lateral or medial translation? It looks like lateral translation? And er also can, can you explain rotation again, please Absolutely. Let me just put the slides back on and we can go through it again. Yeah. Right. So let's start with the rotation regulation. Uh Yeah, fine start the rotation cause that's the first slide I have. So that's just in front of everything else. So, so this is I think might be a better image to explain rotation. So rotate basically, if you think of a bone, a bone is not a two D structure, it's a 3d structure, right? It has uh length and height and width and you cannot really appreciate that very well on an x-ray. But I if if you haven't done orthopedic surgery yet, if you haven't taking a bone out, basically of a wound to, to wash it out or debride the bone ends, then you get the full appreciation of it. Or if you've had saw bones in your hand and you know, you'll, you'll, you'll have a better idea of how the bone might deform. So for example, if you look at this image, you can see the proximal femur there in the acetabulum. OK. So the head of the femur is in the acetabulum and you can see the pelvis and that's all pointing at you forwards as you'd expect from an A P pelvis or an A P of the hip. So this is all, this is all seems, this all seems very standard and you can see this front on as if you're looking at towards the patient from the, from just directly in front of you. But if you look further down, the distal femur looks like it's pointing laterally. So all of the distal femur has rotated along with the knee uh positively and the foot, everything will be pointing towards the outside of the body of the patient laterally, everything will be rotated laterally here. And the way I can judge that is just by looking at this distal femur where the patella is sitting. So this was front on. If this was not rotated, you will see the normal shape of the condyles of the femur as you see them here in the A P image labeled a of the distal femur. But rather what you're looking at is an A P of the hip and a lateral of the knee. OK, a lateral of the distal femur. And that means that this fracture is not well aligned and it's not well aligned in a plane of rot in in in rotation because everything's rotated later. Also, you can look at translation here. So the distal fragment is slightly laterally translated. Compared to the proximal fragment. The fracture is also shortened because the spike here, the tip of this fracture of the distal fragment is shortened. It's overlapping with the proximal fragment of the, of the bone, which really, it shouldn't if the bone did not, was not malaligned. So just to sum up if you're looking at an A P of the hip and a lateral of the knee in the same image. That means this fracture is rotated. OK. You will see this very commonly this rotation in neck of femur fracture patients. You will see a patient who is lying down looking at you. Normally one point is one ft one ft is pointing towards the healing and the other one is pointing towards the wall. OK. Right. Uh Any other questions, guys, guys and girls now is the time to ask. This is all very uh this, this is the basic session. So it's good to ask things now. Yeah, absolutely. And Eddie, no, no reason to apologize. I'm sorry, I'm uh I don't have a better background of oncology to answer your questions appropriately. Um Fine. I mean, I'll start my session now and I um if you guys have questions for either myself or Kareem, then uh please feel free to drop it in the chat as we go along. Uh So let me try and share my slide somehow if this works. Ah, here we go. All right. Can you see that? Yeah, awesome. So, um yeah, so we're gonna be talking about a bit of this is gonna be some basic sciences, which is, you know, obviously everyone's favorite. Um So orthopedics is not about just treating the bone anymore, not just treating the fracture, you got to treat the entire bone because otherwise it's not gonna work. So the objective of this session is describing different types of bone healing that occurs. Um understanding the significance of the different types of bone healing. Um and then learning how to use the different types of bone healing to decide your different methods of management because that's what you need to achieve by the end. Um And then lastly, we're going to touch a bit on nonunion and the general approach to how to manage nonunion, although nonunion in themselves are a massive topic. So I'm not going to go into too much, too much depth. So, can anyone uh give me a, just a, a brief uh single sentence to describe what bone is and cream. Let me know if uh if anyone posts what they say, just have a swing at it guys, we have a swing. Every registrar gets this wrong until you get drilled into you when you're studying your basic sciences. So just have a, just have a go anything. No, nothing yet. No worries. Then fine, let's crack on. Um So bone I always lead with, it's a highly specialized form of connective tissue is essentially what it is. Um You can divide your bone into your cellular components, which only makes up about 10% of it. And your extracellular matrix will the other 90% with your cellular components. You got your osteocyte, your osteoblasts, osteoclasts, your bone lining cells, uh The extracellular matrix you've got primarily is 90% that collagen type one. And then you've got your other proteins, your proteoglycan glyco, glycan c, osteocalcin osteon nein. You've also got a lot of inorganic material, which is your calcium phosphate and your calcium hydroxyapatite. Um When you think about what the different cells do, uh you've got your osteoblasts which come from your mesenchymal stem cells that become osteo progenitor cells and subsequently differentiate osteoblasts. Uh These are essentially uh there to produce new bone, essentially. So, um they will uh produce a type one collagen. Um And they will form new bone and regulate osteoclastic activity. Your osteoclasts, on the other hand, do almost the opposite. So they're from your hemopoietic stem cells, they are activated by the um osteoblasts and they reabsorb bone by degrading uh mineralized bone matrix using hydrochloric acids and carbonic anhydrase, um your osteocyte. Now, some people get a bit confused what these are, they make up 90% of your uh cellular components. But what they actually are is when your osteoblasts produce your matrix around it, they get trapped and then in turn, they become the new matrix and that's why. And that's what the osteocyte are making up the uh a bulk of your cellular components. Um And then your bone lining cells are sort of just there as well. They sort of line the surface of bone. And um uh essentially, they are inactive osteoblasts that can be reactivated when, when new bone is being formed. Now, in terms of the blood supply to the bone it does receive about 5 to 10% of your cardiac output. And with your long bones, it gets um blood supply via the nutri arteries from the me uh meta and epiphyseal system and from the periosteum itself. Now, that's really important because you've got to remember when you're actually fixing fractures, you know, everyone whips out your periosteal elevator, but you got to, can't forget that. Obviously, a lot of blood supply also comes from the periosteum itself. So your different types of bone, you know, people get confused. You've got your me, your lamella bone, your woven bone, but then you've also got canis and you've got trabecular bone, your um and your canis bone. So what's what? Um so the way you think about it is you've got your lamellar bone and your woven bone. But among the lamella bone that can be in turn divided into cortical and canis. So that's how you divide it up. Your lamella bone is your standard normal adult bone. Um It's got collagen fibers arranged in uh parallel layers. Um And essentially with your, they are stress orientated and highly organized. So they're formed into osteon, which are sort of these um er layers of cylindrical um uh well, the of um lam of lamella um and essentially they communicate with each other via your uh Volkman canals going uh laterally. And you've got your herat canals in the middle, which have your blood vessels in the middle of them. Uh Your cortical bone is back up about 80%. They are very dense and they have a very slow turnover. And your canis bone, as you can see in this diagram here is a, a lot less uh tightly packed and compact. Um but it has a higher turnover and it's sort of got this trabecular pattern to it, which is why it's sometimes called trabecular bone. Your woven bone is sort of your bone that's either remodeling or it's pathological because of turnover essentially. Um And what you'll find is that your collagen fibers are not orientated in nice parallel layers, but instead all over the place, which is why they're not stress orientated and are essentially weaker. Now, in terms of your bony anatomy. So you've got your standard um diaphyseal bone here. You've got an outer layer of your cortical bone cortex with periosteum lying on top of it. You've got your osteon forming these rings uh to make up the entire bone with your uh Volkman canals in the middle and you can s er Volkman canals going across, you can see and the va canals going down the middle. Um You've got, and on the other hand, you've got your cancellous bone, which is a lot more trabecular, as I said, more highly vascularized, less dense and has your bone marrow and your blood vessels running through them. So you can see the two different pictures of what they look like. Now, types of bone healing, primary and secondary. And honestly, this is probably the most important thing to sort of get your head around. Uh, when you're thinking about being an orthopedic surgeon because, um, if you do not understand how you're gonna, you're gonna heal the bone, you do not understand how you're gonna fix the bone. And in turn, you will eventually fix things that are gonna fail. And that's something that you will see. um in some people you work with, who do not understand why they're fixing a bone or how they're fixing it. And eventually it fails because they didn't understand the biology or the mechanics. Now, the bone healing and nonunion theory is a, is a paper that was published by al you can see on there as well, some very big names um in, in orthopedics. And they talked about um this overlying theory of how a bone sort of heals together. So you've got tissue in and around a fracture that forms something a spec a specific functional unit called a bone healing unit. And this responds to sort of biological mechanical environments around a fracture in order to allow the bone to heal and essentially either remains active until the bone healing has been achieved or it fails leading to a nonunion and it responds to strain to mechanical forces. So, Wolf's law and variations in the mechanical environment. So you have to talk about parents strain theory and which we're going to talk about and wolf's law. Now, in terms of um strain. Now this is the other concept that you really need to get your head around. So strain, a lot of people talk about strain but don't quite, can't describe it. Strain um is essentially calculated by the length of a bit of bone. I'll just show you the diagram here over um the chain, it's the change in the length over the overall length. So if you imagine something moving around like that, er you take the change at its maximum over what it is at its standard length and that's how you calculate strain and it's given as a sort of a percentage. Now, your stability in turn is to uh is determined by this strain. So you have to sort of understand the strain in order to determine the stability of your overall fixation or how you're gonna manage a fracture. Now, in terms of uh what you need to know about it is it's how the bone deforms. So when you apply force through a bone that what it moves it, that's what the strain, that's what you're talking about when you talk about strain. Now, in terms with this strain, you, the more you reduce the fracture gap, you can also any small movements but cause map bigger de deformation. So you get higher strain, cause it in granulation tissue. Now, you also think about something called strain tolerance and essentially that is the maximum strain, a tissue can tolerate um while still having normal physiological function. And if it goes beyond that uh strain tolerance, then the tissue fails and a fracture can't heal essentially. Now, the way uh this guy on an ot a um no, a trauma talk talked about strain is if you imagine you're trying to build a house, er but you're building on an earthquake belt. If you try keep trying to build your foundation and keep shaking all over the place, you cannot establish a good foundation and establish um a structure that you can build your building on. Um So if the area has high strain because the fractures moving all over the place and it's got a massive change in length all the time. You can't establish fracture and all and essentially uh your different types of tissue can differentiate depending on how much that strain is. So, if you've got a lot of strains, you're talking, you know, strains of 10% 100% you cannot form bone, you cannot form a callus and essentially you're gonna end up with just granulation tissue or complete nonunion. So, fibrous uh nonunion. So you get something there but the fracture still moves, it's not holding anything. Now, let's say you managed to get that fracture all the way together, you hold it and that reduced the strain. Now it can't move so much. But let's say you haven't got an absolute compression, you're not compressing the fracture together. So you're still gonna get a bit of movement. 52 to 5% or some people say 10% you're talking about secondary bone healing. So you start getting callus formation um which we're gonna talk about in a second. Now, instead your last option is you compress that fracture, you really squeeze it together so that there's almost no movement at all. So you're getting less than 2% strain and that leads to no callus formation, but instead primary bone healing. So therefore, we need to understand what primary and secondary bone healing is. So before we get to that stability and absolute stability, so you understand strain next, you need to understand stability. In order to get there, you describe as either absolute stability or relative stability or well or no stability essentially. Now, absolute stability, you can only can achieve by compressing a fra together. If you're not surgically compressing a fracture, then you are not achieving absolute stability and you're ending up ending up with relative stability or uh no stability essentially. So you compress a fracture to achieve that less than 2% strain. And that allows for primary bone healing. So it's described as virtually no displacement, you can never get absolutely zero displacement, but you can get that less than 2%. And the way you can do it is you either compression screw with a neutralization plate. So if you guys see a fibular fracture, when we do um you know, you got your um oblique fracture, you you webb a be you put a lag screw through and then you neutralize it with a neutralization plate. And that will be a different topic of different plating modalities. But just plating again is a compression mode and tension band wiring is also compression. So all of those will allow you to compress a fracture, get that less than 2% strain and get absolute stability for primary bone healing. Instead, relative stability is that 2 to 5%. So there's a bit of strain but not so little that you get absolute stability but not so much that you end up with too much movement and fibrous nonunion, you get secondary bone healing and that small bit of motion under applied loads. When a patient moves, weight bears, then you get callus formation and that you can achieve with cast immobilization plate, fixation, bridge plating or intramedullary nailing is also gonna give you intramedullary um is gonna give you uh relative stability, external fixation as well. So this is just to give you an idea of um what er different types of achieving absolute stability. So you can see on the left, you've got this er sort of um you've got er compression plating. So you can see how you, if you go on your ao course, you'll see how you be a plate. And as you do those er concentric EENT screws, you get compression across the fracture site you've got on the right at the top a tibial plateau that's being compression screwed using partially threaded screws for a lagging by design technique. And then at the bottom left, you've got tension band wiring and then lastly on the bottom, right, you've got er buttress, plating. So, buttressing and then putting a further um partially threaded through screw through the top relative stability cast I mobilization. So that is, that is a type of relative stability. Um A achieved by that, you've got your intramedullary nailing again, you've got a bit of movement at the fracture site, but less than that 2 to 5% allowing for callus formation, external fixation. You can see with this Lazaro frame and lastly in these really smashed comun distal reds, sometimes you just can't put all the bits together. And instead what you're aiming for is some relative stability and you're bridge plating it. So you're spanning that area and just allowing it to form a callus and knit itself back together again. So primary bone healing, like I said, absolute stability less than 2% strain and also er either compressing that fracture together or just getting less than 0.5 mils of distance in that fracture site. So, so much that you don't have to, nothing needs to jump that gap in order to fill in which would otherwise require callus formation. It allows for uh normal bone homeostasis and osteon remodeling. And this is the same mechanism um that normal intact bone undergoes. So your bone is always undergoing this osteon remodeling and what you're doing by compressing this together. You're tricking the bone into thinking it's intact and just doing its normal remodeling. There's no callus and there's no resorption of fracture ends. So that you can see in this picture here is a compressed um clavicle fracture and you can see that there's no callus forming there. Um So what it looks like is you've got uh compression, bring these scratch sites together and this is what's happening in your normal bone. So your bone all the time is, your gaps are just being filled with new blood vessels and either lamellar or woven bone uh filling the gap. So either you've got contact here where the bone is absolutely pressed together or tiny gap healing where there's a few where there's mesenchymal cells becoming osteoblasts and just uh creating these cutting cones. That's the main phrase, you need to remember cutting cones with osteoclasts at the tip which uh go which break down um the current bone and you've got osteoblasts falling behind it, which is remodeling the bone behind it. And these are laying down your new osteon to form new lamellar bone to bridge any fracture gap. So that's what your primary bone healing is. And this is just a bigger picture of er another er blown up version from Rama Chadron of what a cutting cone looks like. Now, instead, you've got your secondary bone healing. So this is probably what a lot of people remember from their med school textbooks about bony healing and this is essentially callous healing. So your relative stability is 2 to 5% strain with a bit of movement at the fracture site. Now, if you don't have that movement, there won't be a callus formation. But at the same time, if it's not squeezed together, then you don't get primary bone healing. So that's something you got to remember. Later on. There's a bit about intramembranous ossification, endochondral ossification. There's not uh this is something more for the FCS level you need to remember. So I won't go into that too much detail. This is what you generally have to sort of know when you talk to patients in fracture clinic about what their fractures can sort of heal like. So what happens at the start? You break a bone, you bleed into the air, you get localized hematoma, you get fibrin clot, angiogenesis, cell recruitment, the necrotic ends get broken down by the osteoclasts and macrophages. And that's what that's what happens in sort of the first, well, first week, first few days, really. Now, during that time, you're gonna start getting callus forming and uh that starts sort of a few days after the fracture and you're gonna get vascularization of that fracture site and you're gonna get mesenchymal cells becoming chondrocytes to, in order to form a cartilaginous callus. Um and that's gonna allow you to have initial mechanical stability. So the fracture initially moves and then as this callus forms, it moves a bit less and a bit less. And then your part three, your hard callus. So over the four weeks plus, um that's when your cart, um your cartilaginous uh callus is gonna start becoming mineralized. So the cartilage starts getting broken down, but the bone starts getting lon laying down as sort of woven bone. And then finally, it starts remodeling from sort of four months to years. You're gonna get remodeling as per normal primary bone healing as per wolf's law, you're gonna get remodeling to lamellar bone and that's how you get your secondary bone healing completed. And this is what it looks like in the diagram. So I won't go into that again. Uh This is just um this is from up in leeds, talk about sort of the requirements for bone healing. So you need your osteogenic cells. You need an osteo conductive cal uh scaffold to build on in order to bridge that gap and hold your fracture together. You need your growth factors, your bone um bone um er BMPs um and your other uh growth factors and you need a mechanical environment. So you need to stabilize that fracture in order to allow for the fracture to heal. So, delayed union and nonunion. Um What's, how do you define them? It's hard to say. Actually, there's been a bit of a disagreement about what er nonunion is in particular. So the way it used to be described is delayed union was a fracture that's taking it's still healing, but taking longer than expected, usually beyond six months. And the traditional way of describing nonunion was a fracture that's greater than nine months old with no progression of signs of healing for three consecutive months. Um where limb recon surgeons may instead describe it more as fractures which lack the potential to heal without intervention. So, surgical intervention or intervention in other forms in order to facilitate the bone healing. Now, it can be done either clinically. So the absence of uh you may have no tenderness, you may have abnormal motion or you may have pain on axial loading on weight bearing with an injury. And also you can look radiologically, you can look for the absence of a callus or there's no continuity on the cortices. So this is um the way a lot of people will be ask you, oh, tell me about nonunion, tell me how you do categorize or er classify nonunion. And the way it used is often still described is whether it's hypertrophic or atrophic. So you divide it into a fracture that doesn't have enough stability, but it's trying to heal, it is vascularized enough, it wants to heal, but it's not quite getting there. So you just see this sort of elephant foot type, um this callus with a still with a fracture gap and you can see too much callus because it's still trying to make bone, but it just cannot bridge it because the strains too high. And the traditional thinking is you just need to fix it, you need to fix it suitably such that you can bridge the gap allow for a strain environment um that facilitates bone healing. And uh the other is atrophic nonunion. So people talk about uh it having in inadequate vascularity. So, fractures that um they might be stable enough, but the bone has been uh stripped, the periosteum is gone. The uh intramembrane uh intramedullary blood supply is gone and it's just an avascular lumbar bone that's not gonna heal. So you'll see sclerotic bone in. So it's, it's given up the battle's over and you need to do something about it. And typically the management would be er revising bone grafting, trimming the ends and trying again now in. So the ways you can look at it clinically, you can look at pain, um pain at the fracture site or sometimes no pain, poor function and movement at the fracture site. Um Radiologically, you can look at two orthogonal views on x-ray. You can um there's for tibias, you can use the rust score. So your scoring on both views um whether there's presence of callus, whether there's fracture lines still visible and you score it um out of four oh out of 12, I think um low scores means it's nonunion. High scores mean it's, it's, it's uh healing well, if you're not sure a CT can be helpful for more uh more sensitive. Look at the nonunion. So you can actually see that fracture line still visible with your 3d cuts. Uh And sometimes an MRI is help if you're worried about infection. So you're looking at collections, anything else like that? Um The problem with CT and MRI is both of them can be obscured by artifact. Now, you do have your um metallic artifact reduction um uh uh cuts or I can't remember um sequences. Uh However, even then you might still get artifact. So sometimes x-rays are your best friend in terms of looking at nonunion. So the question you need to ask with non union is why did it happen? Um You need to know why the fracture has, hasn't healed and what you need to make it heal. Uh the factors you need to look at is you need to treat the patient as a whole. It's not just about the bone. Sometimes it's the patient factor as well. So if they were a smoker, major impact on osteoblastic activity, nicotine, major impact on, on small arterial um vas constriction which in turn prevents blood flow, which prevents you bringing all those chondrocytes, osteoblasts, et cetera to allow the fracture to heal poorly controlled diabetes. Again, a raised hyperglycemia prolonged can cause a hyper inflammatory state that's going to cause problems with your bony healing nutrition. So low album, uh sorry, albumin is not a good measure of nutrition, but looking at the patient's nutrition, their age, any drugs they're taking bisphosphonates, steroids, nonsteroidals. Absolutely. I hate giving non, I do not give nonsteroidals to any patients with fractures, hormonal endocrine disorders. People, a lot of people forget about these. But when you've got a patient with an unclear reason for why they're having nonunion, you need to think about referring them to an endocrinologist to see if there's a hormonal endocrine problem causing their issues, peripheral vascular disease, obviously, poor blood supply leading to, again, poor bony healing. And then you look at the bone itself. Was there bone loss? Was there a poor immobilization? Was it open? Is it infected? Um And what was the soft tissue, uh soft tissue trauma? It's not just about the bony trauma, it's about the soft tissue overlying it. So you sometimes need to get your plastic surgical colleagues involved and get something like a flap or a graft in order to facilitate bony healing. So it's all a balance. You've got to factor all these things in. And I um look at it as you need to firstly, always make sure the patient stop smoking. If they stop smoking. Four weeks down the line, they're already massively improving their chance of bony healing. And if they stop for months, then they're coming back to a normal patient's uh chance of healing. Gluco is co uh glucose control, stop the steroids, stop the nsaids, stop this bisphosphonates. That's one people forget. And if you're worried about infection, well, if you're worried about a noun, you have to check for infection. Look at your CRP, your white cells, your sr and then look at all these other hormonal tests as well. But I'd start with the infection markers first. Hb A one C, particularly if they're diabetic. So, what are you going to do after that? So you've optimized the patient's factors and then you need to decide why did it fail? Was it mechanically unstable? So, like I was saying that a lot of the limb recon uh surgeons start thinking uh you know, maybe there's no such thing as atrophic uh nonunion. So, um the other paper about the bone healing units talked about how uh some of the models they've looked at, don't show that even the fragments they thought were devascularize, still get revascularized as long as you've stabilized the fracture sufficiently. So you're gonna debride the fracture ends, you're gonna compress the fracture and you're gonna try and recreate that bone healing unit. Now, the other thing is if you make it too stiff. So remember why you got to remember what type of bone healing you're trying to achieve. If you're trying to achieve callus formation, like in a long diace fracture, you cannot make it too rigid and stop that and make that strain less than 2% because if you do, there's no callus gonna form, you're gonna get attempt bony healing. But if you've got gaps because it's, um, because you've got a comminuted fracture or there's bone loss or you just haven't reduced it enough, it will not heal. So you'll go on to a, um, a failed nonunion and then it, the metal work will fail me, uh, will fatigue and fail if you've nailed a fracture. Um, and it's gone on to a nonunion things you can think about. You can think about Dyna. So you can take out a bolt and allow the patient to weight, bear so that the fracture compresses under physiological load or you can try exchange nailing. So you're trying to increase the um the stability, you're trying to reduce the strain by putting a larger diameter nail in. And then you can think about putting um sort of other things, biological adjuncts to help the fracture heal. So, bone grafts B MP S, et cetera infection on you. And I won't go into this too much. Cos this is a big topic, but essentially it's associated with either inadequate debridement in open fractures, which is why some trauma centers bang on so hard about open fractures, knee and orthotics opinion and a lot of smaller units go oh, we can manage all these small gust tolo ones. But how do you know it's gust one until you've gone in there? Um You don't because sometimes there's massive subcutaneous uh soft tissue stripping, periosteal stripping and you do not know that until you get in there bacterial contamination at the time of fixation. So poor uh a uh sterile conditions and sometimes failure of primary wound healing. So, diabetics, poor skin conditions, et cetera, optimizing host factors, aggressive debridement of bone sending cultures excising uh sinus tracts, lots of antibiotics with micro guidance and stabilize that bone. If you have to cut a section of bone out, stabilize it and think about what else you can do. A bone graft, bone transport, et cetera. Scala is a technique used in some uh in patients who sometimes have infection on unit, you hack the section out a bone, you put a cement spacer in and you close it up again and you just leave it alone. Come back 6 to 8 weeks later, it's formed this induced membrane around it, which is biologically active. You come back, you carefully open it up, remove the cement spacer, you stuff it full of bone graft, not under tension, close it again and it forms a new bone and that's your masquerade technique, it's very cool. Um And instead you can try er the Lazarov technique. So this is instead way Lazarov is a Russian surgeon from way back, but he sort of talked about this technique called distraction osteogenesis. So you distract um it's distracting forces, you're increasing literally just one mil a day. And what you're doing is you're CRE you're creating first, you're stimulating bony growth, but then every time you, the fracture tries the heel, you're moving the fre you're moving a bit of bone away. So you're transporting bone and it causes the bone and all the soft, all the soft tissue to follow in its wake. So you're stimulating the formation of new skin, muscle, nerves, vascular, connective tissue and bone. Um So well, so all of it together is distraction. His um and essentially it allows you to create a new section of bone. Um And it's done by a few different phases. If you're interested in recon, it's so fascinating. So you just need to read up on it a bit more. Um So we got a case er, very quickly, 37 year old, er, male, I took this case from one of the er ot A talks, I think um cos I didn't have any of my own but this guy involved in a car crash, he's otherwise fit and well, it was a closed neovascular intact injury. Now, does anyone have a suggestion for how you'd manage this patient? Er, in terms of er, fixing it uh cream, let me know if there's any um suggestions there. Just shout, just say type anything. What plate nail, leave it alone. X fix. What do you think anything? Mark cut is saying? Intramedullary nail fixation? Yeah, that's definitely an option. Um I'd say it's probably a bit um it's quite a bit low and it's a bit common, but absolutely in intramedullary nail will definitely be an option. Screws. Ok. Yeah, plain screws would be an idea as well. That definitely, it's quite common. You can manage it and s agreeing as well as we. Yeah. Ok. Absolutely. Now, I think both of those, I think you could easily, easily debate nail or, or, or if either of those are very valid options. Um, the team here did a, er, they, because it was a major trauma, the patient had to be stabilized. First, he went on to have XVI, but then they subsequently converted to a plate fixation. They did me technique. So for those who don't know MPO is sort of minimally invasive, er, plate osteo, er osteosynthesis. So you're trying to do minimally invasive surgery to avoid sort of uh metal, uh soft tissue, er, periosteal and soft tissue damage. Uh and they fixed it like this. Um But what do you think happened next? Any guesses? I guess it failed, it did fail. Well, this is a nonunion to. So, yeah, it did fail shockingly enough. So it, um this is what happened over the next few months. So you can see that uh es essentially it continued to progressively collapse. And at eight months, you can see if you look on that, if you just trace the line of that metal work, you can see that the plates uh it's failed, it's um it's basically gone onto fatigue, failed and if we just go back a slide, what you can see is if you go to, um, if you, uh can you go see my mouse? Yes. Yeah, cool. So you see this gap here? Um What's happened is this is a locking plate and what they've done is they've locked above and below. So they've quite, you know, they've held it quite rigidly, but there's still quite a big fractured line. Uh There's still quite a big fracture gap there. So, um what's happened is uh it's, it's too, the strain is too low to allow for sufficient callus formation. It's too big a gap for primary healing to jump across. So that fracture really needs to be compressed down. If you imagine bec whenever you fix a fracture, it's always a race between the bone healing versus the metalwork failing. Um And what's happened is the fracture is trying to come together. You can see that callus trying to form, but it just can't get enough stability and it's collapsed and eventually the bone hasn't healed. So the plate's given up and then it, it failed and that's what's happened. So what did they do next? They went back in and they compressed the fracture. So you can see this is a, this is a lag screw. So they've used that screw to compress the fracture together. So they would have used a lagging by technique. Um So actually, if you look here, you can even see a bit more um space around this screw on this side compared to that side. So you can see they drill over drill with a 3.5 and they do a 2.5 drill on the other side. And that means that when you tighten this, it compresses across the fracture site and then they've replanted it and what's happened now, you can't see the fracture line. It's all come back together again. So it's not. Oh, and they did a CT that proved that there's non union there. So that's helpful. So Markman is asking, would they have aimed to compress the fracture? But it didn't quite work out or should they not have used the locking plate in the first place? I think this is a very good question mark because in this instance, it seems that there is a mixture of principles that have been used. Yeah, I, I think that's definitely, it's a very interesting point because, you know, it's easy for us to look at these cases and go, oh, obviously that wasn't gonna heal. But um it's difficult because firstly, you've got a um you've got a uh a me. So a me you ha you can't um stuff it full of screws because firstly, you've only opened yet a few small spaces. This patient would have had three small cuts. Um So it's difficult at that time to compress across it. But yeah, I think a plate would have been fine but yeah, that fraction needed to be reduced some more, it needed to be compressed together, whether by literally just pushing it together while fixing it or whether by doing compression screw in the first instance or um, as, er, I can't remember who mentioned it, an intra intramedullary nail would have allowed for compression over it. Now, I don't know whether the mechanism trauma meant they couldn't do an intramedullary nail. But um I basically, it needed to be compressed together because it's too far apart for primary bone healing and it's not stable enough for um for relative stability to fully, to fully um heal that fracture as a with a callus. Um So yeah, uh any other questions about that, that all making sense guys? So, in very basic terms, if you have anatomical reduction and you have compression at the fracture site, then you really shouldn't be seeing callus because what you're getting is primary bone heathing where you have the cutter cones coming across. There's no, there's no hematoma at the fracture site. And that's why you do an open reduction, internal fixation in order to achieve anatomical reduction and then compress the fracture as much as you can and de bride the hematoma usually. But if you're seeing hematoma, then you've got relative stability, that means you're getting secondary bone healing when and in this case, that, that, that uh Mister was describing just now, you should not be using an implant. That's this rigid because it will not successfully unite uh quickly enough for the, for the bone to carry the stress rather than the plate that for this fatigue been failed. Yeah. Cool. So Jamal is asking, is there a window period for a successful union? Um So it's, it's a very difficult question and actually you can always debate these nonunion cases for sort of how long you're gonna leave it before you decide? Oh, it's a nonunion. I need to intervene. Um And it varies between patients. So some patients who obviously have a lot of medical comorbidities, they're smokers. You might want to think about leaving it a bit longer where younger patients who are very active and they should have no problems with bone healing and you see no progression on serial xrays. Those are ones where you start thinking sooner that, yeah, this is not going to heal. It's, it's all about weighing risks benefits. And are they going to go on to Nonunion or are they not? It's never an easy decision. It's something you have to sort of look at um all the different patient factors. What their likely healing potential is like, how good was your fixation. Um But often you do it by, if you see, you know, serial x-rays over a few months and there's no progression, you can be pretty confident that's not gonna change. And then you need to start thinking about revising it pretty much soon after. There's no point in leaving it longer than that, but some people you wanna leave longer. There's no hard fast rule about how you do it. And, uh, so he was asking, would, would it have helped to have ac arm during the surgery? Iiii I imagine they did because, uh, you, you can't really me her without it because otherwise you're literally just sliding a plate blind. Um, but sometimes the not use the arm if they, if they are doing open surgery and they can see the bone for the bone in mo mostly in its entirety. For example, some people who are doing femoral fixations and per prosthetic fractures, they will do, they will pla out the femur and sometimes x-ray will be just a flash again or if you're doing a clavicle fracture, it's usually a flash again to make sure that your screw length is normal. But if you're doing a me bo fixation, it would be very, very brave to do that without any x-ray to basically show you where you're going the position of your plate and where your screws are in terms of the fracture. 100%. I mean, if you imagine it's like, you know, you're trying to imagine you're blindfolded and you're trying to put screws in something, you know, you can't see anything without in an image intensifier. So, um and I think, you know, a lot of people are, you know, oh, I only need one flash at the end uh, it, sometimes they're a bit bold. I've seen, you know, fibular plates that are sticking out the end. I have seen clavicle plates that are too long where they're sitting off the bone because people think they're very confident with where the, where the plate is and they're not, I, I am quite er, judicious with my image in tens by usage. I don't know how you are Kareem. But, um, I, I like to be sure rather than not. Yeah, I, I feel the same me junior, the, the end of the day, we don't have, you know, years of experience and so having that extra bit of support always helps make better decisions. Uh although might take it long term on eyes and thyroid glands and testicles and so on. Uh I it's also your evidence. If it's also if, if something goes wrong, you know, you've got your proof that look, I had this position was perfect. You know, it was like this, I did this and your, your e image intensify shots are your story of, of how the case went. And um I, I think it's helpful but obviously as you, you know, you take fewer shots, the more senior you get, the more experience you get. Um but I think it's always good to use it to at least check your plates um perfectly sighted before you start fitting screws in because once you've committed to screws, you're in trouble. If it's in the wrong place. Uh, I was asking another one about, uh, if there's any evidence for using the special ultrasound probe thing? Is it called exo for non unions or is it just expensive sorcery? I, um, I must say I have no experience with it. I know it's talked about, it's mentioned in Ramchandra and it's mentioned in a few, er, of the main textbooks. I don't know, I've heard it does but I've not looked into the evidence. I can't, I can't tell you. Unfortunately, I've, I've heard of it as well, so I haven't looked at the evidence of it either but, and I've, I've heard from some ss surgeons experience. It can be useful, but I don't know if there's, it's used in a standard manner. It's certainly not used at, uh, nor, nor in any standard way. It's usually done in like private physiotherapy clinics and private clinics as well. Um, sorry, you know, I, I just think the best people to ask would be just ask any of the limb recon surgeons. Do they use ultra? And I'm betting the answer is no. Uh, finally, Jama is asking, are all of these plates standardized or do you use patients specific plates? So, uh, there are anatomical plates that are shaped to, uh, to bones, specific shape of, of, of a specific bone, not really for a specific patient. So they're not patient specific, but they are location or bone specific. So, for example, you have the uh distal uh femoral plates, you have the proximal tibia plates. Uh There's the lateral malleus anatomical plates. So, these are all called anatomical plates. These are standardized but anatomical to the shape of the bone in the average human being, you'll see that in a lot of cases, they don't exactly fit the patient and sometimes a little bit more of con contouring is required. Uh But yeah. Have you ever used the patient specifically, sir? Uh No, I mean that that would be uh I can't think of a good reason to use them, to be honest because for the most people, you can, as long as you've reduced a fracture, well enough, your um anatomical plates usually will fit the bill. And um you know, sometimes you don't even need the anatomical plates. If you do try to do like buttressing, you can use a, a completely non contoured plate and then obviously you're using the plate to you do the compression. So, uh I don't know, I've, I've not seen any used. Um But I'm sure there's any reason to use those very, very expensive devices. I've seen 3D, I've seen 3D uh uh shaped, not plates per se, but devices that can be used for osteotomies specifically to a surgeon patient in specific cases. So there are very patient specific implants out there. I know there are certainly uh total knee replacements and hip replacements that are 3D printed based on CT scans uh for patients that are done in advance, but in terms of plates, it's trauma. So usually you'd have to go by something that's standard. You wouldn't want to delay surgery for the patient to get a CT scan and prepare a plate and uh and then use it specifically on this patient. And like I said, mentioned, it's not really any added value in most cases, a, a lot of it just comes down to having a good technique and knowing what, knowing how and why you're trying to fix the fracture a certain way. All these fancy things essentially at the end of day, compress your fracture, reduce it well and hold it in that place and things will go fine as long as you've and protect and don't strip the periosteum. Um I'll just go into the summary just quickly because I think some of this is covered there. But essentially in summary, uh you know, you need to determine the method of method of fixation, which is determined by what type of bone healing you're trying to achieve. Uh the different types of bone healing are desirable in different circumstances. Obviously, you don't want any callus in a joint. Um But for long diace or fractures doesn't really matter. Um A number of factors affect bone healing and these need to be all of these need to be considered when um trying to get a satisfactory fracture healing. Some takeaway messages you need to treat the whole patient. Um It's not just about getting the fracture right. It's, but it's also about um treating, stopping them smoking, stopping them, taking their nonsteroidals, making sure, you know, you've looked into the hyperglycemia looking, you know, anything you can optimize the patient, you need to do it in order to maximize the chance that they heal. Reducing the fracture is probably the most important part of any fixation because that is what gives you the most ability. If anyone ever asked you what conveys the most stability you start doing about, oh, near, near far, far. Oh, I'm gonna use more screws. I'm gonna use this, uh, locking plate. No, the answer is you reduce your fracture plan. What you're trying to achieve with your operation? I mean, I think I've said this a few times but, er, too many people go into surgery not understanding what they're trying to achieve with the plate fixation either you're going to put, you know, you see people using bridging plates where they shouldn't, you're using, you know, you're trying to compress when you've got a commun fracture. It's insane. It's never going to work. And you know, someone's, someone said I can't remember who it was. A hole is an opportunity, not an obligation. You got these thick locking plates, you stuff them full of screws. We had a case, er, a few weeks ago. Um, it was a, a distal femoral fracture and it was used a lock, a nice thick locking plate, but there were so many screws in it, it was a rigid solid construct with a fracture gap and it, of course, it did not heal. Then it went on to fatigue, the plate went onto fatigue fail and the whole thing collapsed. And now it's a, a big revision, er, complex trauma case. So, just because there's screw holes there don't fill it up. If you know you're gonna try and bridge, then you don't need to fill it for the screws. You want it to have a bit of movement for relative stability. And that's why you've got to know what you're trying to achieve before you enter the case plan your cases and that's it. Right. Uh How I stop sharing my screen. Uh OK. Thank you very much seb that was uh that was a, a little bit less uh less basic than uh than my, for sure. I got caught up in it a bit. Sorry, I'm sure I'm sure it's very, I learned uh I learned a lot on this one as well guys. So, uh do you have any questions for myself or seb before we sign up while you guys uh have a quick think if you have any sort of feedback or any suggestions, uh please direct them to mag Goodun, he's one of the core trainees as well in uh east of England and he's the Cogan for these uh for this uh series of lectures. So uh just direct me feedback and questions about uh the format or uh the plan going forward to him. And uh yeah, would be very useful uh after the session, hopefully, you guys should have some feedback forms pop up. Please fill those out to get your certificates for the session and let me know if you have any further feedback. Um Next week, it will be uh proximal tibia fractures, ankle fractures. I'll have a quick chat about uh midshaft tibia fractures as well and hopefully, uh if everything goes as planned, we'll be joined by Mister Ben Kwanza consultant, uh knee surgeon. No, March. Um That'll be a really good talk. He's a, he's a con. Yeah, lovely stuff. Ok? Thank you very much, Seth. Appreciate the, the time. Thank you very much for joining us and see you next week.