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Right. Ok. Who anyone know who this chap is? Mhm Anyone know where this person worked? Jeff me and then, then Fair Points, Tessa, he said to me because I remember seeing his um picture in the corridor. Is that Joe? Yeah. Yeah. Okay. Yeah. He worked at the Norfolk and Norwich. Yeah. Yeah. He wrote the book on the left and uh he's called Tommy Britain. Uh He was a consultant at the N and N. What's he famous for Joe? Having his picture on the, having his picture on the Maquis corridor? Absolutely. Pass the book on the left. Has a small clue. Anyone. Yeah. Okay. So, uh this guy designed a hip fusion which was based on the flying buttresses of the Norwich Cathedral. Okay. Uh And this is the picture from this book which you can actually pick up relatively cheaply if you're interested in old books of the internet. Um And so this is the copy of it that I've got. So uh this book shows you about the very basic principles of arthrodesis, but also has got some beautiful pictures and drawings in it, of lots of different joints uh and how they can be fused. So is quite interesting. He was working in Norwich at the same time, uh or similar time as Mickey who is Mickey. Uh Not Andy that works in uh in Peterborough. So we have another Mickey in east of England. Anyone know what Mickey was famous for in knowledge and the country slash internationally. Anyone seen the Mickey uh marble bust as they enter North Hospital? No. Uh Yeah, absolutely. Do you don't think about it? My core as one of the early hip replacements. It was. So he was working at the same time as Charlie. Uh and they actually did some work together and actually the Maquis Far. A hip replacement has its own place in the Charlie Hip Museum in writing tongue. So they're working at a similar time and they did share some ideas that they both had very different ideas about how best a hip replacement would work. And there is a British Ship Society uh podcast Legacy series that has been done. You might have seen it on Twitter, but Norwich have participated in that and spoken about the Mickey Far, uh and the hip replacements that have come from there. So there is a lot of hip history and knowledge that uh clearly we're not very good at keeping alive, which we need to work on. But, um, yeah, so we've got very rich history uh in arthrodesis and in replacement now, unfortunately, mckee Far uh implants didn't really do particularly Well, um they were a metal metal bearing surface and actually it came from a very early hip replacement that was actually a cloverleaf that was screwed into the acetabulum. So there are some beautiful pictures which at some point I will get around to scanning and uploading on to the East of England website. But um definitely a beautiful history to go into given the fact that it's from the region you're training. Okay. So Britain used bone to be able to fuse joints in this situation, which is how we're going to move into bone crafts, long, long winded introduction there. So his initial fusion looked like this and it's fusing the ileum to the fema. So this is an iliofemoral extra articular fusion. Didn't actually do anything to the joint itself. Uh Why was he fusing joints at this time to reckon on cases he looked like in the war? Yeah, he did. So um it could have been for trauma, what it was probably not the main reason for why they were fusing at that time. What disease was more prevalent around that time that we don't see a lot of now, there's a lot of TB that affected uh the joints in particular the hip. And so people would have uh onset of arthritis early and they would have fusion. Uh So uh this is predominantly done for TB of the hip at that time. So, really imagine the kind of what was going on in that department where you have what you've got to orthopedic surgeons working in one department. And you've got one surgeon that believes infusing the joint and another one that's desperately trying to, trying to create and invent a hip replacement. And this race that is going on between knowledge, exeter and writing tongue and trying to get a hip replacement that worked quite an interesting time. Interestingly, the two of them didn't get on particularly well. And there's a couple of nice stories that Keith Tucker told in the podcast. If you want to listen to it on your commute about the interactions between mckee and Britain. Britain then started to develop different fusion techniques at the same time that the hip replacements were being designed. So he moved on from what was an iliofemoral fusion two, then X rays that looked like this. Okay. So he's put a struck graft in, but he's also started supplementing it with um metal work. So it still has its iliofemoral uh point, but it has an issue. Ephemeral fusion as well. Any ideas on what he called this? What shape is it? A delta place? A is a V fusion, right? So the V of the metal and then the uh graft. So that was a whistle stop tour really of an intro into uh bone grafts. So, a bone graft is any material that has got a potential osteo conductive inductive or osteogenic properties. Now, it might have one or it might have all three of those properties. It might be something that is bone or belongs to bone or something that is completely synthetic. Okay. So if you asked what bone graft is, I would keep it very simple and just focus on the properties of a material. Okay. You can use bone graft to fill a defect, which I think is probably the most common reason why we would use it. So if you've got someone with a protrusion oh hip and you've got a lot of bone loss medially and you want to fill that up with graft, you might want to use it structurally, which is what they've used it for infusion setting. But actually in a lot of tumor surge, particularly Children, you might use bone grafts from its structural properties, but actually might also use it for a bone formation and say management of non unions. Okay. So you can then start talking introducing how you use bone graft into your definition. Uh We've mentioned some of the properties of bone graft already. So osteo conductive is purely a scaffolding or a framework that bone can grow into. Okay. If it has osteo inductive properties, it's got factors around that can stimulate bone to form. And if it's osteogenic, it contains the cells that can make bone okay. Which sales are they osteoblast? Uh mhm Good. So contain Austria lists and osteo sites, okay, as well as means and kind of stem cells. Okay. So that makes up your osteogenic types of graft. And obviously the different graphs are available, have a combination of these properties. So we know we have autograph which is bone that is taken from ourselves and used within our bodies that might be taking some iliac crest and grafting that into a non union. It might be taking part of my fibula and grafting that on to the end of my radius. If it's that, I've got a tumor in the distal radius. Okay, an allograft would be that I borrow bone from somebody else. So it might be that my patient's got a protrusion oh hip. And I want to graph the floor of their acetabulum and I use bone graft from another person by means of a frozen femoral head. Okay. Then we've got the synthetic options which are materials that have different properties that will go through and the properties we've been through, but they don't all have the same properties and obviously don't forget the xenograft that would be borrowing from something else. It's not very often that we do that with bone, but obviously, I'm sure many of you are aware of it for different tissues like bovine pericardium or Saks, etcetera. So, within autograph bone grafts, you then have the different types. So you can use cortical based bone, which is good for structural support, cancellous bone, which is a bit better for filling voids and then vascularized free fibula, which is something that we use a lot in tumor's uh to be able to reconstruct. For example, the end of the distal radius, your allographs can be fresh. Although we don't really typically use those fresh frozen and freeze dried. So these will be your dry croutons that you get your fresh frozen would be when you defrost a whole femoral head from the bone bank, for example, and then your synthetics are your calcium sulfate, your phosphates and your hydroxy appetite's which have different resort option rate. So it depends on how long you want that graph to be around for as to which one of those you you decide to use. Okay. Just to bring specific attention in the allograph section, we were using freeze dried croutons. They are literally just a scaffolding. There's nothing else there other than a scaffolding for the bone to grow into. And so the fresh frozen femoral heads, for example, have got that additional benefit of being conductive and inductive. Hopefully everyone's happy that that's relatively straightforward. But again, this is the structure that I would use. If I was asked to speak about bone grafts in the exam, there are risks obviously associated with the use of bone graph, which I think sometimes we forget that might be particularly important to patient's and we can't just assume that we think it's low enough and not mention them. So I always put bone graft on my revision consent forms, for example. So plus minus bone grafting. Um And I will mention the specific risks of bone grafting to them in the clinic letter, but as well on my consent form. So for HIV, it's actually about one in 1.5 million risk of getting HIV from an allograft bone graph that's been used about one in 60,000 for HEP C, about one in 100,000 for HEP B. The reason I've put particular attention to putting this in is is that I got this question in my MCQ for my part one. OK. Um And it was asking to match up the relative risks which I think would be different for you now because you don't have extended matching questions, but it just as easily lends itself to a single best answer. Okay. How are you going to council this person to the risk of Hepatitis B on having an allograft used for their petruchio hip? Okay. And then don't forget that these uh samples that are taken. So if you have a hip replacement and you donate your femoral head, yes, you're tested for HIV HEP B and HEP C. But there's never any histological sample taken from that hip to prove that there's not any early cancer in there that you're not aware of. So if you are known to have cancer, you can't be a donor. There's nothing saying that you haven't got it and don't realize it's about 8% of femoral heads are donated. Have some form of pathological bone within them. Now, some of those are benign like an osteoid osteoma and some of them might be a met or a primary bone chima. So again, they don't, they're not zero risk. The graphs incorporate in different ways. So you do need to have a read around this chapter in Ramachandran personally. It took me a couple of reads to get my head around this. I've tried to simplify it, but you do need to be able to talk about how the different graphs integrating. Generally speaking, it's the difference between can sellers and cortical bones are the ones that they're wanting you to talk about in the exam. Okay. So graft inc itself is the process of invasion of the graft by host bones. The host bone has got to grow into the graft. And generally speaking, there's an inflammatory phase, it becomes revascularized, there's osteo induction and then remodeling if we speak about cancellous bone, but this will be slightly different. Um And we'll, we'll talk about that as we go through. So cancellous bone, if you're only going to remember one buzzword about cancellous inc is creeping substitution. Okay. And that is where there is a very rapid revascularization of the area that's grafted and osteoblasts will lay down new bone at the same time as the osteo class resorting the graft. And there is this remodeling process that occurs, okay. It's relatively quick and in the process, um the X ray becomes X ray changes will be more dense and there is actually an increase in strength around the time that the graft is integrating. In comparison to cortical bone, which will come to in a minute where actually becomes weaker before it gets its strength back. Okay. And all of this happens because of local changes, the surface osteophytes, osteocyte survive because of the rapid revascularization. And the osteo bars are able to lay that bone down because the graft has got factors that can induce it. Okay. So, ephemeral head, you take that cancellous bone out of it, you graft it in and this is how an allograft of cancellous bone would incorporate. So creeping substitution, the new bone is formed at the same time as osteo class resorting the graft. And so it's this constant remodeling that is occurring. If you compare that to cortical inc it's much slower for revascularization. And in my mind, I remember that as the cortex, cortical bone is obviously very hard and you can imagine that it was very difficult for vessels to get into it mentally. That helps me remember this and this is all then subsequently done using cutting cones which again you imagine is going to be a little bit slower. Um And the osteoblasts are forming bone at the same time. Okay. And so there is no remodeling phase here because the cutting cones are simultaneously doing it. The initial uh initial changes of the graft host interface are of enchondral ossification. And you then later, once all of the graft has been resolved, then get apposition all bone formation. So you will see that the bone can get wider. And actually in some of the pictures in Britain's book, you see that the graph that he's used in the fusions actually gets wider and they make a point of talking about it. And this is this difference of how cortical bone incorporates. The most important thing here for the MCQ is that cortical bone uses cutting cones and there's no remodeling phase. So that is the simplest way I can get cancellous and cortical integration down. Um It does need some reading in Ramachandran to kind of supplement this. But also I think one of the common questions that you can, well, I say common, it occasionally comes up is how to set up a bone bank. And if you get that in your part too, and you've never thought about what's needed to set up a bone bank. I think it would throw you quite significantly. But there is a couple of pages in Ramachandran that talks about how to do it. So they're worth reading. Okay. Um As I mentioned already, when cortical bone integrates, it gets weaker before its strength comes back. And again, that's a significant difference between your counselors integration and your cortical integration. And that again lends itself to an M C Q question. Um Oh I was gonna ask you guys. Can you draw a cutting cone? Have you got any paper with you? You can take five minutes. Enjoyed cutting cone. Okay. Everyone quickly. Google. Is it? Mm Maria. Are you signed in? Do you want to talk through a cutting cone? Who else has got their exam soon? Fish G channel high. Go ahead. Hi. Hi, I'll give it a go uh cut, cut a cone. Uh I can try it by describing is hard. It's, it's responsible for primary bone healing and atomic lee cheap like a cone with osteoclasts at the front which uh is responsible for the cutting part. It uh dissolves bone um through uh well, it's a complex process but mainly uh acidic. Uh what's it called? Um um I can't run the name now but at the back of the uh Kohn is the osteoblasts which lay down new bone. Um And the cones move forward. Um uh With the osteoclasts classed, removing uh old bone, both organic and inorganic uh components and then uh osteoblasts and lay down new bone as, as the cone is progressing forward. Um I think that is uh the best I can describe it. Yeah, that's fine. Thanks. G Shan's good. So, yeah. So at the front of your cone, you have your Austria class and this is the area that's resolving a bone and behind it, you'll have your osteoblasts and they're centered around um uh this black area here, which is part of the cutting cone and is actually a vascularized area. And if you take a cross section of this once through an area that's complete, okay here, that is actually part of your heart version system. Okay. And so you could very easily be asked to draw a cutting cone and they might ask you for a cross section, for example, through the osteoblasts. Does anyone know what it is called when an osteoblast gets trapped by its own matrix? What they then become known as osteo sites? Yeah, osteocyte, well done step. So you can start talking about these being Austria sites back here. Okay, when they're trapped in their own matrix good. Um I haven't really done anything more on uh bone grafts because I actually think it the question style when it comes up is more centered around a clinical case and you'll be asked to talk about what type of bone graft do you think you would use in that situation? Um And then they will ask you to talk about the risks, the benefits and then how it integrates the things that they might push you on our, talking about what factors affect how some, how a bone graft in, in um uh integrates the word I'm looking for. Um And so you can talk about the medical factors, the graft factors um and how you've used it. Okay, fine. We'll finish up with just a few cases. So um I'm happy to either do this as if junior registrars would like to comment first and then we'll go to the guys doing the exam or if the exam guys would like to go straight for it. So, is there anyone would like to have a go at doing a basic science fiber? I mean, don't all Russia once we'll stop the recording now, actually.