Just gonna shut down my webinar chat. So thank you for, for joining this session on, on managing complex fractures, and, the plan is for the next sort of 50 minutes or so, we'll start by going a little bit back to basics. We'll consider the biological and mechanical aspects of fracture healing.
And we'll think a little bit about the concept of strain in the fracture gap and how that affects the development of of tissues in the in the sort of sequential steps of fracture healing. And then we'll move on to the sort of bigger picture approach. We'll think about the the the techniques that we can use, how we decide which is the most appropriate one.
And I think, I hope it will become apparent that even many complex factors can be dealt with really quite simply, if we understand and apply the, the appropriate principles, so. I will see if I can get this. Oh no, we might have fallen at the first hurdle of advancing my slides.
Oh, there we go. There we go. Biological and mechanical dams.
Well, it's very, very simple. The, the, the biological demands are to have a good enough blood supply. The mechanical demands, the, the, the idea of stability is a little bit more complex, and as I say, we'll talk a bit more detail about that as as we go through and I think it's important to stress that fractures will not heal if they're not stable enough.
And so when we're talking about degrees of instability, we're talking about sort of micro motion or excessive micro motion, gross instability and no fractures is going to heal. So that that's kind of common sense. So think about the, the biological aspects first of all.
And healing is says there is a complex and sequential set of of of events and as we understand more about fracture healing, we understand the importance of cytokines, bone morphogenic proteins, particularly stem cells, how important they are to the repair. And I think trying to sort of keep this this talk a bit practical, recognising that the major sources of a lot of these cells are the endostium, the periosteum, we've got to be very, very good about how we handle our soft tissues and as we approach our, our, our fracture repairs. The the old saying is that a fracture is really a soft tissue injury with bone involvement, and I think that's that's really important.
So if we consider our our biological environment, that's heavily influenced by the sort of fracture. How the fracture was caused. So if you look at the two images there, and you know, we have a relatively simple fracture in a young dog.
It's not complete. We've got healthy soft tissue. We've got an intact ulna, you know, this is, this is a fracture that's destined to heal.
If you look at the fracture below, this is a, a high energy fracture caused by a a pellet injury, and this, this poor cat's leg has exploded apart, and I think you can all appreciate the state of those soft tissues. You can see the opacity, you can see how much soft tissue swelling there is there. So that, that fracture is, is going to be really, really problematic no matter what we do.
So we've got the the history of the fracture, but then we have our surgeon influence and and this is where if you like, we often talk about surgeons being carpenters or or gardeners. So the carpentry approach is basically going in there and and being determined that you're going to get every single piece of that fracture back together. So you can have lovely post-operative X-rays and feel very good about yourself.
At the other end of the the the sort of spectrum we've got the so-called gardening approach where our priority is really, really need to look after those soft tissues, the blood supply, the periosteum, and to try and, and create the best environment for fracture healing and and do less with the bone, if you like, to to to put the bone ends in approximation to hold the main fragments together, but, but really to pay attention to those soft tissues and. And there's a whole spectrum along that or there's a whole lot of options along that spectrum if you like. So, we we gonna talk about this as as we go through.
So, I'm not gonna dwell more on the, on the biology. I think that we all recognise the importance of preserving our soft tissues, and I think that that the stability is the is the aspect that that takes a little bit more, more thought, and we all know that fractures have to be stable to heal. But why is why is stability important?
You know, it's something that students often ask me, and you have to, you have to really think about it. So we know that stability is important so that the the sequence of tissues can develop in the fracture gap. But it's also important because it's painful, and we need these animals using their legs as quickly as they can.
And we want them weight bearing well within a within a few days of our fracture repair because loading of the bone is very important for fracture healing. So stabilising a fracture is the best analgesic. And so there's a lot of reasons that we want to get that fracture appropriately stabilise.
So stability inherently linked to strain and I apologise on a Saturday night for getting a bit technical, but strain is the the change in length or the original length, and we tend to express that as a percentage. So what does that mean? It means if we have a fracture gap like this.
Something like a 2 milli gap for, for example. If a 2 millimetre fracture gap increases by 2 millimetres, we've got a 100% strain, which is very high strain, OK, and we don't like high strain environments in our fracture healing. If we start off with a slightly bigger fracture gap.
Here's your first question. If we had a bigger 4 millimetre fracture grab and it increased by 2 millimetres, what would the strain be? So if you think about it in the context of the fracture healing, we're saying we've got a certain gap and we've got a little bit of movement.
So I'm gonna, I'm gonna leave you to, to answer that question. So we're just letting people answer at the moment. It's a bit mean, isn't it, on a Saturday night is very mean, but I think good because it just keeps us all awake.
We're, it's, we're coming to the end of, we started this, Sandra at midnight. Obviously not all of us have been around all the time, but, it's been quite a long day. Of course we have some of the Aussies and Kiwis and Americans coming in, so it kind of spread it out around the time zones.
But anyway, people are voting. We've had about half the people voting, so I know we're. It's a, it's a maths question, which is a tiny bit mean, but let's have a crack at it.
Nobody will know if you got the answer right or wrong. So I'll give another 5 seconds, 10 seconds, make a quick decision, go for it. So, I think, yeah, people are sticking with that.
So we've got 73% think it's it's 50%. Now, we've got the other one down as 100% in ours, but we meant 200%. So obviously, just The top one is 50%, 73% have said 50%.
I think there's a clue in the mistake in the question really is there? Yeah, yeah, yeah, and 20 27% have said 100%. I 200%, so apologies, we've probably put that down wrong.
No, no problem at all. So the, the answer there, if I can, it's interesting, if your pole is open, I can't change my slides. Right, let me just I'm gonna do it that way.
So the answer is 50%. So it's the change in length divide which is 2 millimetres divided by the original length. And the the point of that is that.
If you have a little bit bigger gap, it is a little bit more forgiving if you want to think about that, of the of the same amount of movement. So if we've got a little bit of instability, but we start with a bigger fracture gap, it keeps our strain lower, and this is important when we when we talk about the different methods of fixation and why it's really important not to have tiny gaps with any movement, for instance, when we put plates on, but we'll come back to that. So strain is important because it determines the type of tissues that can exist in the fracture gap.
OK, so if we think about that, hopefully everyone will remember from from school or veterinary school, fracture and gap healing is is a progression of, of a series of tissues from granulation tissue to fibrous connective tissue. Then we get to fibre cartilage and then eventually we start developing woven lamelar bone that that remodels over a number of months and The point about the strain is that if we, if we think about the very early components in our frature gap, we've got granulation tissue, which is really very stretchy if you want to think about it like that. So granulation tissue can elongate to almost double its length before it starts to rupture.
So if you have a bit of movement in your fracture gap, you can still develop granulation tissue. As your fracture gap, elongation starts to reduce, so we're we're dropping down to about 20% strain, then you can progress on to the next stage of fibrous connective tissue. And as it drops down further, we can start to lay down fibrocartilage, but only when the strain gets very low to about 2%, can we start to really lay down bone in that fracture gap.
And the important thing is, if you're strained, so if your stability, if your strain never drops below about 10%, you're going to have problems with your healing. So you're going to start getting delayed unions, you're going to start getting non-unions. And that hopefully that sort of segues nicely into the, the, the idea of direct and indirect bone healing.
So if you remember again, back to veterinary school, and there are really two types of bone healing. You can have direct or primary bone healing, and the requirements for that is very, very low inter fragmentary strain and a very small gap. For indirect secondary bone healing, which is the natural type of bone healing, we can, we can do that if we have a little bit higher strain in, in our fracture gaps.
So again, remember we're talking about small amounts of movement. We're talking not about gross instability, and the image there is to to give you a sort of illustration of that in action. I'm not sure if you can see my mouse there, but we've got a multiple metacarpal fractures there.
The main weight bearing ones have been stabilised using bone plates. And if we look on our medial lateralies there, we really don't have a lot of callus forming. So I think we've managed to achieve good stability with our plates and we managed to get good reduction there.
However, with our metacarpal here, we're allowing that to heal by indirect bone healing. You can hopefully see there's quite a bit of callus forming there. So it's, it's a nice illustration of if we manage the strain in the fracture gap, we'll get one of the two types of healing, the direct healing or the, the indirect or secondary bone healing.
And if you remember back, really it's the, the indirect bone healing that's the is the natural type of of healing. And it goes through these three phases. We've got our early inflammatory phase, we've got our reparative phase, and then we've got the more prolonged remodelling phase.
So initial fracture, we get rupture of our blood vessels, we get hematoma formation. Then we start to go into development of granulation tissue, connective tissue, fibro cartilage, all of the time where we're dropping the strain in our fracture gap. And then if we get to the stage of having a low enough strain and stability in that fracture gap, we're going to get woven bone, lamellar bone.
And I think it's really important at this stage to recognise that one type of healing is not better than another. The, the benefits of primary bone healing is that we have conditions of absolute stability, which means the animals are much more likely to be comfortable and using their leg early on. And the other advantage is that you born is sharing a lot of the load.
It's not completely reliant on your implants because you can think of fracture healing as a race, between the fracture healing and your implants failing in many circumstances and the and the more we can protect those implants. With conditions of of absolute stability and good bone load sharing, and then that's one of the advantages of a primary bone healing. But ultimately, primary and secondary bone healing, the eventual outcome, is just as good.
OK, so we're talking back about this sort of concept of, of the fracture gap and strain within the fracture gap and the body helps us in in dealing with this. So the body reduces strain in the fracture gap, first of all, by absorbing the fragment ends. Radiograph or fracture and radiograph it a week later.
Sometimes your fracture gap will look a little bit bigger, and by sing the fracture ends, the fragment ends rather, and that's dropping the strain because it's making that fracture gap a little bit bigger. And afraid that the beg your pardon, the body also acts to reduce the strain in the fracture gap by forming callus because if you think callus is starting to stabilise your fractures, so you're reducing the movement. How we influence strain in the fracture gap is through our our choice of fixation.
So the type of fixation we choose, the size of fixation, and how, how we apply it. So if you look at these two, images of, of fracture stabilisation, this is something that that my students always struggle with. If you look at the, the plate on the left there, the dog has lost a little bit of the ulna, but the reduction of the radius is really not too bad.
There's a very small gap there. However, if you look at the, on the right, we've got our external fixator with a tied in iron pin, got quite a big fracture gap there. So why is having a big fracture gap there?
Not important. Now have you, have a little minute to have a think about the the concept of strain and and mobility. Have a think about which of those two repairs, which fracture gap is at risk of having the very highest strain.
OK, it's gonna be the one on the left here. So we have a very small gap. We should have very rigid fixation.
But if our fixation is not as rigid as we think. We're going to create a real high strain in that fracture gap. And this is why we will often see plates fail when we have a transcortex that's not really very, very well reduced.
OK, with our external fixator tied in iron pin here. We know this type of fixation is far less rigid, so we're likely to have a little bit more of a flexible fixation. So we're gonna have a greater change in length of our fracture gap, relatively greater change in length, but our fracture gap is starting off much bigger anyway.
So we're gonna still have a lower strain environment. So that's why we have to be very careful if we're using very, very rigid fixation that we don't create tiny little gaps of high strain there. OK, so I hope that makes, makes sense.
So having having had a quick sort of tour of the the the the biomechanics, let's think about how do we approach factors, how do we make our plans, and I think if you can anticipate challenges, I, I think you can get yourself into to far less trouble. So when I, when I start to approach a fracture repair, I always start with 4 basic questions. First of all, can I anatomically reconstruct the fracture?
Because if you can't, it's going to take you down one route of a number of different fracture fixation options. If you can anatomically reconstruct it, then you have to think about whether that's the most appropriate thing to do in that particular fracture scenario. Then I asked myself what condition are the soft tissues in, so I might have decided that a fracture is reconstructable.
I might have had a mind to put a nice big compression plate on, but if that soft tissue is associated with that fracture, if that's an open fracture, if those soft tissues have been badly damaged, then I'm going to reconsider that, OK? Putting a bone plate in with the associated surgical approach, surgical time. Perhaps that's going to compromise my soft tissues too far.
The next thing I consider is how long do I think the fracture is gonna take to to heal and is it going to be subjected to very large forces. So I may treat an identical fracture, let's say of the radius in a two year old cat. I may treat that very differently.
To a similar fracture of the radius in a 10 year old obese Labrador, because the latter I know is going to be problematic. It's going to take longer to heal. It's going to be subject to larger forces.
So even for the same fracture, you're taking a step back, you're considering the bigger picture. My last question is, will that really suit the animal and the owner? So for example, there, there really is no point in putting an external skeletal fixator on a very aggressive German shepherd and owned by an old lady.
So I always start with deciding whether I whether that that technique will be appropriate for that particular owner. And then I think about whether I've got the skill and the equipment to do it, but we'll come, we'll come back to that. OK, so if I if I decide I can reconstruct it, then I'm going to consider an open reduction internal fixation or or if approach as shown on the, the right of the screen there.
So. What this involves is precise anatomical reduction of the fragments, and as we mentioned briefly to start with, if you can get the bone to take some of the load, then that's going to decrease the stress on your implants, making it less likely your implants are going to fail, and certainly less likely they're going to fail before your fracture has healed. And as we've said as well, if you can stop a fracture moving, it's a tremendous analgesic, and the animal is going to then start loading that fracture which is going to further stimulate your bone healing.
OK, the downside, much more extensive surgical approach, a lot of soft tissue disruption and often an increased risk of infection. So it's a good example of where we're thinking mechanics versus biology. If you're going to do this kind of repair that's shown here, and I think we've probably, we've probably over stabilised this fracture, but if you're going to go for a for an anatomic reduction and fixation, you have to be sure that The compromise you're making to the biology, on balance, that it was necessary to do that.
So you're always weighing up mechanics versus biology. And this is a this is a nice example of overfixation. So I'm sure that you, you all are aware that, distal radius and on the fractures in, in small terrier type dogs, very problematic healing.
There's a, there's a reduced blood supply to the distal radius in these little toy breeds. So we aren't gonna want to fixate them strongly. We're going to make them very stable.
It's a, it's a disaster if you try to get away with casting these or or maybe putting a little fix on. So you do need good rigid fixation to start with. But I think that that that's fairly excessive on the left and and this is really just to make the point that you can start to get stress absorption, so get stress protection and bone absorption.
If you remember, Wolf's law that the bone and remodels based on the loads that are applied to it. So if we're really overprotecting our bone, we're actually going to get bone resorption. So we're looking for a nice stable fixation, we we really don't want to be over fixating things or we end up with the scenarios we have here, which is a bit of a disaster.
These are the only bone plates that I will take out routinely are plates that I put into dis distal radiuses for that very reason, and you would never start off with that number of screws, a very nice fixation, but far too much metal work. If I was faced with taking that plate off, I would probably take every other screw out, try and load the bone a little bit more before I would take that plate off because as you can see here, a lot of weakening, you're going to get pathological fractures. OK, yeah, if it's not possible to anatomically reconstruct it, I might take a biological or bridging approach.
Now, it's a bit silly, I think, to call it biological because all fracture healing is biological. So we'll go with it, we'll go with the bridging terminology. And you can do this in in one of two ways.
If you have the sort of fracture that can be close reduced, then then you you don't have to obviously open into your fracture site at all, much, much better for the soft tissues you're protecting that fracture envelope if you like. But in some cases, we might make a little approach just to line up our fracture ends, but we're not going to to do anything terribly invasive there, so we, we call that the sort of open but do not touch. And the important thing about this sort of technique as as illustrated on the the image there is the idea is that you are aligning with two main fragments to restore length.
But you're leaving the intermediate fragments alone, OK, that's a really, really important, important rule. Because what you're doing is you're preserving that envelope, if you like the soft tissue envelope, the blood supply around the fracture site, and therefore it's biological healing potential. If you start to interfere with the intermediate fragments, then you lose all of the advantages you you gained by this, this bridging approach.
So take your two main fragments, line them up, make sure that you've restored the length of the bone, make sure there there there's no angulation or translation, but leave the the intermediate fragments alone. So the disadvantages of this, and we Basically, we don't have any, in most cases, we don't have any load sharing with the bone. Our implants are taking all of the load so there's a risk of failure.
So we need to to know that these fractures are gonna heal quite quickly. We don't want to be putting these on our older be Labrador if we can help it. We've got adequate, and it comes back to this idea, it's not rigidly stable, but it's it's adequate for fracture healing, but we're going to get indirect fracture healing.
We're going to get healing by callous, which is, is not a problem if we have a fracture in the middle of the diaphysis, but clearly we don't want to be doing this if we have fractures close to joints or certainly not with intraarticular fractures. We don't want a lot of callous formation. And obviously there is the, the, the more frequent rechecks and the, the, the second procedure often to remove our external fixator.
So more and more often people are are trying to to meet in the middle if you like to to to go away from the sort of carpentry, anatomic reduction, open everything up, line it up perfectly. And the other extreme of the sort of gardening, well, let's just sort of put the two main fragments in alignment that nature do its courses. It's sort of newer bridging techniques, people minimally invasive plate osteosynthesis.
It's trying to take the advantages of both. With the disadvantages of either if that makes sense. So what we do with this is we, we will take a pre-contoured plate, and we'll often make a little portal through the soft tissues at the top, and we'll slide the plate down along the edge of the bone.
And then we will make small approaches to put our screws in at either end. The other example here, we've got an iron pin in the middle and we'll come back to to why we will sometimes combine these implants. So we've got.
Good rigid fixation. But because we haven't opened it up, we haven't put screws in every hole. We've preserved a lot more of the biological environment and of that fracture site.
So it's a nice compromise, where appropriate, between the two extremes, if you like, the two opposite ends of the spectrum. But it's still got to be strong enough because it is a very technically demanding technique. And as you can see this is a What you might describe as an epic fail here unfortunately, a very common fracture of a cat's femur, certainly not one that's reconstructable.
It has had an iron pin put in and then a plate that has, turned out to be too weak. So this, this plate has, not provided sufficient stability. The iron pin has backed out.
And the whole fracture has collapsed. So I think it's really important with fracture repair that you learn all the rules before you start recognising which ones, if any, you can, you can break. So although me is very popular at the moment, you can't go too far down the scale and end up with a fixation that isn't strong enough for for the job there.
OK, so, you need to then take a step back and look at the bigger picture. So we've talked a lot about looking at the fracture, deciding whether it's reconstructable or not, and deciding whether you should reconstruct it, thinking about the soft tissues. And this global, picture, this fractured patient assessment score ties this all up with, is it suitable for this particular animal and this particular owner.
Now, there There are scores that you have that you can actually add up and come up with a number which sort of pushes you towards one type of fixation or another. But I think most people recognise that that's not really the best use of these scores. And, and they're they're really better just a way of making sure you've considered all of the important factors in, in, in your particular patient.
So we're not looking to come up with a number at the end. We just want to make sure we, we consider the, really these three main sort of groups of factors. So biological fractures, which are gonna affect the time to heal.
So we've already talked about this. What's your fracture like? Is it a simple fracture?
Is it an open fracture? Is a comminuted fracture? The other aspect of this time to heal is your patient, you know, have you got a young healthy dog?
Have you got a very old, old cat? Have you, have you got an animal with other disease that might compromise healing? Have you got multi-joint disease?
With our mechanical factors, we've talked about strain, we've talked about how we can modify strain with our fracture reduction and our our fixation techniques. We've got the forces, the weight bearings, the muscular contraction, you know, we we got have we got very active animals, have we got sensible owners that are going to confine them after their fracture repair. And we've talked about whether or not the fracture is reconstructable and able to load share so that the bone can take some of the load off of the implants that we're we're going to use.
So we talked about that. And then we think about the the clinical factors. So, have you got a a lovely healthy cat, such as my cat there?
Have you got a dog like Mighty Mike, who was a 65 kilogramme Labrador? Didn't have a fracture, but had bilateral cruciate disease, but as you can imagine, he was a difficult patient to treat. Or have you got what we lovingly refer to as a little land shark, a little dog that you would rather really put a plate on and not see till it was having its six week radiographs, rather than come back every week for external fixator checks.
So I'm being a little bit facetious there, but we have to be able to manage the patient appropriately afterwards. So there's there's no point in putting a very clever, fixation, external fixator on an animal that you subsequently can't really take care of. So we think about the appropriate matter based on the type of fracture we have.
Let me take a step back and we review all the other factors in deciding whether that's the one we're going to choose. So, we're going to spend the next little while, trying to apply some of those, those principles. I'm going to, to get you guys to do a little bit of thinking now.
So my first case here, we'll have a look at that and I'll give you a little bit of time to decide whether or not this fracture is anatomically reconstructable. I think Anthony might just be having a little trouble at the moment with his sound, Sandra. Say that again.
I think Anthony might just be having a little problem with his sound at the moment. Oh, can you hear me now? I think I must have just pushed on the mute.
Oh yeah, he's back now. Thanks, Richard. It's sorry, Sandra, it's 79% saying it's anatomically reconstructable and 21% saying it isn't.
So the majority think that they can reconstruct it. Oh gosh, you're brave people out there. I'm, I'm gonna say no, based on the, a little bit of comminution there and that's what you've got to be a bit careful about about rather is the the whole idea if we're thinking about.
How we're going to repair this. If we are, as we're often going to do, put a bone plate on this, we need to remember that that we can't have any little gaps, particularly in our trans cortex. And I'll I'll show you the repair in a minute what I should have done, or you guys, if you could have asked, might have asked me what kind of patient is it?
Because again, very, very important, is it a young, healthy animal with great healing potential is an older dog. And if I remember rightly, I think this was a six year old Labrador, and the choice in this case was to double plate it. OK, so let me have a little look at that repair for a minute and see what you think.
There is something I would be a little bit concerned about with that. Anyone worried about this little bit here? It's very odd asking myself questions that no one can answer.
So for me, it's it's a nicely placed plate and there is a bit of a gap there and it's under a screw hole, which I'm sure you'll all recognise, makes that a very weak spot. And I think that's why the surgeon would have put this extra little plate on because If we've got this little gap, we're going to create a high strain environment. We're going to potentially cyclically fatigue our plate and put it at risk of failing through here, especially as we have an empty screw hole.
We're going to prevent that with a little plate on the ulna there because that's going to almost act like an intact transcortex. OK, so have a look at this. This was 6 weeks later, and, and see what you think.
What, what type of bone healing have we got there and what does that tell us about our repair? OK, so hopefully you you're all noticing that we've got some callus forming. OK.
So the fact that we've got some callus form and it's quite obvious tells us that we haven't got the ridges stability we'd associate with a bone plate normally, so we're getting some indirect bone healing. So I think in this instance, if we hadn't put that plate on the ulna, this, this plate would have failed here. So when you look at your post-ops, we'll talk in a minute about the different things you, you assess, but the first thing to say is, have we got evidence of healing?
We definitely have. We've got quite a lot of callous, so we might be a little bit worried and we'll restrict this dog a little bit more carefully until we, until we get complete thought and union. But there's no sign of it.
The implant problems, there's no sign of that plate starting to fail. There's no sign of those screws pulling out that the more observant of you, I think we recognise that these are are locked in. Some of these screws are locked in, making that a more rigid construct than a normal dynamic compression plate.
But it shows you that it's not as stable as we thought and we're starting to get healing, but it's by indirect or secondary bone healing, which means we didn't get that absolute rigidity. OK, so have a look at this one. And just think about whether you think that's reconstructable or not.
That's your first question. It's not a poll question, but think about whether you think you could reconstruct it. And the question is, what would be the most appropriate way to stabilise this fracture?
OK, I'm going to tell you that it's a 3 year old German Shepherd dog. So I'm just letting people vote at the moment. Sandra, so we've got .
A few people being brave, a few people not being so brave as to vote, so if you want to vote, give it another 10 seconds just to make your mind up, . Remember, we don't know who you are. Yes, exactly.
It's a, it's a nasty fracture though, isn't it? I think that's gonna keep you busy for a while, isn't it? Well, is it though?
Oh, you're giving away something, are you good? Let me, yeah, I think we'll, we'll stop the. The poll there.
So we've got 7% saying they would just plate it at 25% plate and rod, ESF 25%. ESF with tied in IM pin, 45%. So lowest just for using a plate, there's then 28 and 24% for plates, rod and ESF.
Nearly 50%, 47% saying they do ESF with tied in into medullary pin. OK, so I'm gonna close that down. And so my answer is one of two.
So you could really use a plate rod or you could use an ESF with a tied in iron pin. So if we think, hopefully you'll recognise that that wouldn't be reconstructable. It's quite a nasty fracture, but it's a, it's a young, healthy animal.
With a plate, you would have to have a bridging plate. OK, and that bridging plate would have to be really very strong because you, you have no bone on bone contact over quite a length of that femur. So your plate's gonna take a lot of the strain or a lot of the stress on those implants for quite a long time.
And if you remember, plates are not very good at bending. And so it's going to be quite a lot of bending forces on that fracture while it's healing. It's a big dog.
The way we get around that, the way we counteract those bending forces by putting an IM pin in, OK? An external skeletal fixator on its own is, is definitely not going to work because of where it is. So if you think you've got a femur, you can only use a type one external skeletal fixator.
So it's, it's basically unilateral and that's not going to be strong enough on the femur. You've got the body wall in the way, which isn't going to let you put a bilateral frame on. But we can strengthen our ESF tying it in with an eye in, OK?
So if you, when you start to combine fixations, you've got to use fixations that that make up for each other's weaknesses, if that makes sense. So in both of these instances, we're using IM pins because neither the plate nor the ESFF are very good against bending if there's big areas of comminution. But an iron pin is super strong against bending because it's put in a sort of protected area.
It's down the middle of the bone, which is what we call the neutral axis. So it's in a relatively protected area. It's very strong against bending, and it counteracts the the slight weakness in the plate and the ESF against bending.
And if you all remember what iron pins are not good against this, they're not very good against rotation at all, which is what your plate counteracts and your ESF counteracts. So basically, by combining either type of fixation with an iron pin, you're making it a very strong fixation. OK, so I hope that makes sense, but we can chat about that at the end if if anyone is confused.
And that's what we did with the cakes there. So we've got a nice plate on there and we've got an IM pin. We've left those, those fragments, the centre fragments alone.
We haven't gone in there and disrupted that too much. We like to always put IM pins in a normal grade direction, so you're introducing them just on the medial aspect of the the greater toant there. And a nice plate that's spanning most of the length of the bone.
Remember, you're going to downsize your iron pin compared to your normal iron pin so you can squeeze the screws around at either end. I think if the observant people of you will notice we've managed to snap one of the screws there. OK?
So that makes that a very strong strong fixing, fix fixation. Uneventfully. OK, case 3.
I don't think we've got this as a, as a pole case, but this is, think about whether that's constructible. This is a young cat. I think this cat was about 13 months old.
We should know it's a cat because it's got a super straight femur. It's fantastic for plaiting. It's got quite a long pointy little patella as well, so.
Do we think it's reconstructable? How would we like to, how would we like to fix this? This one was reconstructable, and so we put a plate on there, and it was a straightforward standard neutralisation plate, because we didn't have a transcortical gap.
We weren't worried about that plate fatiguing, and there are one or two things to notice though about that. So hopefully the more observant of you if we go back, notice that this. Little cat had also knocked its capital y seal off, so it had a sort of Harris and fracture separation of the capital yus there.
And the owner's choice was to do a femoral head and neck excision based on on financial limitations. So rather than repair that as well, and that was a a a a one stage procedure. Now, critiquing that, we'll talk more about that in a minute.
Fracture reduction is fine. We don't worry about these little fragments. I'm often asked, should we remove these and you really shouldn't just consider them bone graft, especially if you've still got muscular attachments.
No reason to take them out at all. Critiquing it, the plate could certainly have been longer and it's quite high. You've only just got away with that screw there.
So really that should have a little bit further down, but this was a very young, healthy cat healed very uneventfully. OK, this is a pole question. Have a look at this fracture.
Nice spiral fracture of a tibia. This was a young, healthy, I think this dog was another German shepherd, actually, and it was just about 2 years old. So this is a classic spiral fracture of the tibia.
And Your choices are, would you like to fix this with a compression plate, a neutralisation plate, a bridging plate or an ESF? So I'm gonna give you a minute to think about that. I think carefully, because it is a bit of a trick question.
Just giving people a chance. So we've got, the majority of people have said an ESF 60%, compression plates, 20%, neutralisation plate, about 15%, and then bridging plates about 4%. So the majority are going for ESF.
Excellent. Good. Well done.
I'm very impressed. So if we, if we think about, so we wouldn't use a compression plate because we've got a a a long spiral fracture, and if we try to compress that, that's gonna collapse. OK?
We don't need to use a bridging plate because we we have a column of bone there, and one of the limitations for both a bridging plate and a neutralisation plate is just how far down this fracture line is going. OK, so we've got a fracture down down there and we may have a little element of fissuring that's not so obvious. So if you think about the rule for plating, we always want to have 6 cortices, ideally in either main fragments.
So we we we'll easily get our 6 cortices up here, but we would really struggle to get 6 cortices down here. OK? We're gonna definitely take compression plating off the table because it's sheer.
If this Line had stopped here and we had a nice segmental fracture. That would have been a lovely one to put a neutralisation plate on with a couple of la screws, that would have been a beautiful repair. But because we've got this fracture line.
And possible fissure line way down here. We're going to use an ESF and we're gonna place it transarticularly, OK? So it's still a bit of a worry and in fact in placing this, we've slightly displaced our fracture, but we've got more than enough bones stuck up here to get our pins in.
We've bridged the joint temporarily. We have one pin here, which is a potentially risky strategy because this bone fragment here might rotate a little bit around that pin. But we've got enough good bone stock to hold down in these meta metatarsal regions.
So this is really to introduce the idea of external fixators and how versatile they can be, because quite often we can use them to bridge joints temporarily, both for fracture repairs where we are quite short of bone stock down here. But also if we are protecting ligament repairs or tendon repairs, very, very effective way of stabilising joints where perhaps bandages and casts might be problematic to, to manage. OK OK, so I'm a big fan of external skeletal fixation.
We've got a very comminuted fracture down here in a little cat femur. You have just enough room to squeeze a couple of pins on. And this is going to heal very quickly.
What we don't want to do is we don't want to go in there, open up that soft tissue envelope, start trying to do anything with these little fragments. We're basically holding our very proximal and our very distal fragment, and we're letting nature do do the rest. So I hope what might be coming across is the idea that although some of the the the fractures appear very complex and very problematic, if you apply Principles and logically think it through.
Sometimes you can, you can use very simple fixation to get these, these complex fractures to heal. OK, so now we're gonna, we're gonna change tack a little bit and I'm going to show you some postoperative fractures for you, you to, to critique. So I'm not sure if you, you've all heard of this sort of, it's the 4 A's.
So if you think about what the four A's might be in assessing your fracture repairs, the first is alignment. How do our line or how do our joints line up? So we really want our joints.
Levels to be sort of parallel with each other and parallel with the ground. OK. It's a very general generalisation, but so look at your joint angles, look at your alignment.
Then we want to look at a position, how, how are the fracturings, are they opposed well? Have we got a huge gap? Are they very man aligned?
Then we'll look at our apparatus. Are we happy with where we put things? Have we put things too close to joints or too close to fracture lines?
And then We look for activity and obviously this is going to be in our follow up radiographs rather than our immediate postops. So consider alignment, opposition, apparatus and activity. I'll give you a little minute to to look at that fracture repair.
So it's it's been a common to fracture in a cat's femur, and we've gone with a with a plate rod. So my question to you is, would you be happy with that? Or would you do what we call the walk of shame?
The walk of shame is taking it out of X-ray and taking it back into theatre. I should have done the walk of shame. OK.
So if you look at this here, It's a nice theory. It just wasn't well applied. So our plate far too short.
OK. We've got a lot of room up here to get our screws. We've got a lot of room down here to put our screws.
Really the only bone on which we're going to put plates that are quite short is that is the carpus really with these femurs, and we want to bridge the length of the of the bone. So this hasn't provided enough stability to protect our iron pin, which is backed out. As soon as our iron pin has backed out, our fractures collapsed and, and obviously our, our proximal fragment has, has, has, collapsed inwards there.
So that's a, that's a disappointing repair. OK, have a look at this one. Ask yourself the questions.
Is it reconstructable? Are you going to try and reconstruct it? OK, so hopefully, hopefully you'd recognise that that that would be a challenge to reconstruct there.
And this was the, the postoperative repair. So first of all, ask yourself, have, have they tried to reconstruct that? Or had they used breaching fixation.
I think it would hopefully be obvious to all that it's a bridging type fixation. But critique the repair. OK?
Using your raising your 4 A's. So alignment. OK, the alignment's not great, is it?
So on a medial lateral view, your joints aren't quite parallel, but this is actually quite forgiving. So if you have a fracture repair where you have somehow rotated your distal fragment in this view, the animals are still usually quite good about using their name. But on a craniocaudal view, if you've created a valgus to that degree, hopefully you can all see those joints are are really quite maligned.
That animal is really not going to use its leg well at all. Is, for some reason they're not keen if their paw is a little bit tilted, they're not really good at putting their paw down. So we've got quite a a a malalignment there.
Apposition. OK, our opposition really isn't great. Got quite a big fracture gap there.
And we've got a lot of empty screw holes there, so that's really not ideal. And a plate isn't terribly well contoured, but hopefully you may be familiar with locking plates and the fact that you don't really need to contour them terribly well to the bone. That's probably irritating the soft tissues quite a lot.
So not terribly happy with that repair, and sure enough it it failed, and I'm afraid really that's destined to fail. We just had too many rules broken there. We have too big a gap.
We've got quite a span of of weakness. Our screw arguably are a little bit too close to that fracture, and we've got quite bad malalignment and poor position there. So that that plate has fatigued and I think if you're if you're still awake and being very observant, still got our staples in and that's filled very, very quickly.
OK. So that was, that was not a good fracture repair. OK, so have a look at this one.
This is our, our last one of this this sort of quiz. Would you be happy with that? I say.
I can hear the, I can hear the whispering. I would be very happy with that. I, I think that's, that looks like a really nice fracture repair to me.
We've got a plate that's spanning, spanning the entire length of the bone. It's obviously a bridging plate. We don't, we've got some.
Empty screw holes here. It's a locking plate, so it should be quite strong. Hopefully you all know with locking plates that the whole system has to fail for it to fail.
It's not like a normal non-locking plate where you know, one screw can fail and then another and another with the locking implants, it's, it's almost like an internal fixator, so the whole thing has to fail. So I would have been quite happy with that, but surprisingly that also failed and It's really, really hard to see why that is, but there must have been just too high a strain in that environment that's allowed cyclic loading. You can see there's been some instability, so we've got some callus formation.
But we've cyclic fatigued that plate, so I think that the point of putting that up is that, you know, even when you think you've done a really good fracture repair. Sometimes you, you come in for a nasty shock and it's all to do with what's happening with your, your straining your fracture gap there, unfortunately. OK, so we're on the last few slides just to briefly sort of go through complications and not spend a long time on this, but the important thing is to understand and recognise that most fracture failures are the fault of the surgeon, I'm afraid.
So acceptance that it's probably your fault and trying to learn from it is a, is a really, really important part of it. Know the limitations of your implants. We've talked a bit about that as we've gone through, but more importantly, know the limitations of your own ability.
I think that's really critical. OK, non-unions, if we don't get our fracture gap strain, excuse me, low enough, if we don't have enough stability, if we've chosen the wrong implants, we, we'll get a delayed union, and then eventually, if we're getting new activity for 34 months, we're going to end up with a non-union and I put these quite . Ridiculous examples really as an exaggeration, so we, we shouldn't be putting small pins in the radius and no rotational stability at all right into the carpus that was destined to fail, unfortunately.
This was less obviously destined to fail, but this was was a very small toy breed dog that didn't have a strong enough fixation to start, had a number of implant problems, and then went on to develop an atrophic non-union. And this is a fracture that wasn't fixed and it shows you what an effort nature makes to try and heal. We've got resorption of our fracture gap to try and basically to try and reduce the strain of the fracture gap.
We've got a lot of callus starting to form, but we've just not got to a low enough strain to allow that tissue to start to ossify or mineralize rather, and we've got a non pardon. A pseudo arthrosis there. So, of all of these, this is the most problematic one.
So the atrophic nonunion is the kind of end result of all other non-union. So when you start to get bone resorption like that, and you really are in trouble to get that to to heal. OK, so if we're gonna treat non-unions really for ways in which we're going to approach it.
If we think there's any possibility that it's unstable, we're going to really head to improve that stability. That's the first and most important thing. Then we're gonna debride any infected or necrotic tissue.
We're gonna try and kickstart activity at the fracture site, and then we're gonna be careful with our post-op. Management. So I think number 4 is very easy.
We we need to really make sure owners are managing the animals, restricting their exercise, and we need to be very proactive in checking these animals. You know, we might get them back weekly or we might radiograph them every 2 to 3 weeks to make sure that we've actually got progression of healing. OK, so if we think about the first one, improve stability.
Again, makes me very sad to see a single little lonely circle wire never going to do any good on its own. So this, this was a really good idea. This would have been a lovely repair if the fracture gap had been a little bit less.
And if someone hadn't gone in to try and make perhaps themselves feel better by putting a circle wire because Obviously you would strip off a lot of the soft tissue to get that little bit of wire in there and circle wires on their own just act as a fulcrum. If you're going to put circle wires in, you need to put in more than one, so, very close to being a very good repair, just let down by a bit too big of a fracture gap and a little cirlge wire in there, so. We're gonna go in there.
We're gonna put a big bone plate on. If we can compress our fracture at all, and we couldn't in this instance, it's better to try and compress it. So sometimes if it's a suitable fracture, what we'll see, people will do is say, well, basically cut the ends of the fracture so they can actually compress it.
So first and most important thing is, if you think there's any instability, go back in there, make your fracture as rigid as you possibly can. OK, this is an example of a case of mine actually that failed. We had a little gap there.
Far too high strain tried to heal, but fractured through it was a dog that had bilateral forelimb fractures. Luckily, one side healer uneventfully, but this side just wasn't good enough. We had to go back in and cut the bone short, put a plate down the medial aspect and compress that, and that went on to heal uneventfully.
So you have to be quite brave. You think it's unstable, go back in there and stabilise it properly. So this is your last question.
You've got to remove any infected or necrotic tissue. So if you have a look at A, B, and C, tell me which of those, or in which of those would you be concerned about osteomyelitis? So we're just letting people vote there, Sandra, .
Just let them go on a little bit longer. OK, we've got 15% of said A. 60, I think they can take a couple of answers on this if they want to, by the looks of things.
So 68% of said B. And 61% have said C. OK.
So I'm just gonna close your pole down and, and the answer is A and B. OK. So this is, this is a nice example that some sometimes it's very hard to tell the difference between callous and infection.
So what we've got here is you've got a really big callus because if you think about the fixation, we've got an iron pin trying to stabilise a femoral fracture, and there's no way. That's going to stabilise the femoral fracture unless you had a very unusual interlocking sort of fracture, because this has no rotational stability at all. But the but the leg is trying very, very hard to stabilise itself by forming a lot of callus.
In contrast, here and here, what we've got is is an irregular periosteal reaction, particularly here spreading well away from the fracture site. So the the way in most cases you can tell the difference is an osteomyelitis tends to look more irregular. It tends to spread.
Long away from the fracture site, whereas a callous tends to be sort of concentrated around the fracture site. So it's not always possible to tell, but that's that's the kind of main sort of clue to to to tell you that this is really just a callous trying to form, whereas this is infection there. And sometimes if we're very unlucky, we'll see something like this.
So hopefully you can all see we've got a very sort of central and lucent area and they're in a very opaque bit of bone here. So your squetrum is B, which is your dead piece of bone in the middle. And A is your invollucrum, which is really thickened periosteal reaction, increased bone deposition trying to wall this dead piece of bone off.
So if you have a sort of chronic osteomyelitis and you're seeing this, you need to go in and do ride that out and pack it with bone graft. But that's quite unusual for it to get to that extent. And then we want to stimulate activity at the fracture site.
So we're gonna go in, I think the message I'm trying to get across is, if you think you've got a non-union, you have to be brave. You need to go in there, you need to to bride out all your sort of fibrous tissue. You need to drill the ends of your, your .
Bones so that you can open up the medullary canal and then you're gonna put bone graft in them if you're using autogenous Cus graft, we're gonna get all of these apart from structural support. Obviously, the structural support comes from cortical grafts, but these don't have many of these other benefits. So most of the time if possible with non-union, you want to go in there and can a bone graft easily available.
Can cause a bit of discomfort in the collection, but it's the best thing to really get your non-union going. Obviously there are a number of commercial bone morphogenic proteins, for instance, you can put in as well. But really, if you can getogenous conus graft, get that in there, pack that in and then compress your your bone ends if you can.
And I think the most important thing, sort of to to leave the complications with is the message that stability is key. So again, a lot of people worry if you have an infected fracture, should you go in and take all the metal work out? And the answer is not if it's stable, because if you, if you go in and take the metal workout, you end up with an unstable infected fracture.
If you leave your metalwork in. The fracture will heal. You put it on antibiotics, you put the dog cat on antibiotics.
If you can get samples for cultures, it can be very specific. You keep the animal on antibiotics till the fracture is healed, and then once the fracture is healed, you can go in and take your metalwork out. So really, fractures will heal in the face of infection as long as they're stable, so don't rush in and take your metal work out unless you absolutely have to.
OK, so summary, ask yourself if a fractures reconstructable, then ask yourself whether you should try to reconstruct it to balance up the biological benefits against the mechanical benefits. Always think about the soft tissues. Then think about your patient and your owner.
Plan and prepare well. I always go into theatre with a plan B and a plan C, just in case I find, I don't know, a fissure line or something unexpected. I always, always, always have a backup plan.
Never ever go in and think, well, we'll open up and have a look, because that's a recipe for disaster. And be very critical and assess your peers and learn from your mistakes. I think that that that we all make mistakes and I think you learn most from being very, very critical and going back in next time and doing a better job.
OK, so thank you very much for your attention, to this, this time on a Saturday night and I'm very happy to to take any questions if anyone has any. We've got a couple of questions here if that's OK. In case it refers to a slide.
Yeah, that's . Can you hear me OK, Sandra? Great, so Andrew said.
Have you had cases of cats dying hours after good recovery following open reduction due to possible thrombbi? If yes, do you apply any preventative measure, e.g.
Heparin. You know, I, I haven't, is the honest answer. I think the the only incidences of that I've I've seen reported really have been related to joint replacements.
So there are a number of of reports when you're doing a joint replacement, you're opening up the medullary canal, you're reaming it out. And you, you basically seed off a, a, a lot of thrombi, and it's quite scary to look at echocardiograms of what's going on when that's happening. People have done that in studies, but it is, it is very unusual even in those circumstances to to have that.
Result in a fatality. So I, I actually haven't has the has the person who asked that question is that, is that something they've experienced? It sounds like they might have done.
So let, let me just see, Andrew, have you had that problem yourself? Cause that would be, you can see the kind of. Sense of it, I suppose again, perhaps an older cat, so wait, let's wait and see if Andrew answers that.
Yes, he has. And was that an older cat, Andrew, or what was, what was the, what was the age? While Andrew's doing that, Hillary said, is it better to leave a gap between fractured bones rather than try and oppose them too much?
How much is too much? Do you know that's, that's that's a really good question and it's, and it's always a very difficult question. I, I think, I think the rule is, if you are going for.
Absolute stability. Let me put it, let me put it the other way. If you have a, a, a slightly more flexible fixation, such as an external fixator, and having a gap is not too much of an issue.
OK? The, the problem we have with gaps is when they are create a very high strain environment. That's, that's the issue.
And I think it's, it's always very confusing when you talk about that. So to know, you really want, you really want to have your fragment fracture ends as close together as you can. Yeah.
OK, but be careful. I think the the the simplest and the most common problem we have is when you leave a little transcortical gap. And so I suppose what's the best way of putting it?
If you're going to go in and try and reconstruct things, then you really need to do that as well as you can. If you're not trying to reconstruct them, then having a little bit of a gap is very forgiving, but don't have such a gap that you can't, you know, your bone ends can't heal. You, you really don't want to have gaps bigger than the sort of bone diameter, for instance, they're never going to, to heal.
So that would be a very low strain environment, and it's still, it's, it's, it's too far for that bone to, to, to bridge. Hillary said, is it worth using a part cast with a plate on some of those distal radius fractures? No, no, you, if you put if you put on, you really shouldn't need to put a cast on.
And the, the problem with with cast is, as I'm sure everybody knows, you start to have all sorts of problems with pressure sores and so on. And with these little distal radio fractures in toy breeds, . If I was in general practise, I would probably refer them if that was an option because they're always problematic.
The the best way you can get these to heal is to put good internal fixation in, ideally with compression. And then monitor the animal for 6, 12 weeks with radiographs. And if you start to see stress absorption, think about removing those implants a few months down the line.
And these are these will never heal in in casts, and I know that wasn't really the question, but if you put a good bone plate on, you, you really shouldn't need to put a cast on the, on the outside. OK, that's great. Andrew just said the cat was 3 year old, so quite a young cat.
I, I think that's an extremely unlucky and unusual incident. I, I also been maybe a road traffic accident. Something going on that.
I would not imagine that to to be it's it's a very interesting case report, but it it wouldn't be a very common thing and we wouldn't routinely and preemptively treat animals for that possibility. Great. Sandra, that is fantastic.
Thank you so much. I think it's been a really good orthopaedic session. We're gonna have a little break now and then you should have a link for our final webinar of the day, our final seminar, which is on behaviour with Sarah Heath and Karen Overall, who's quite famous, very famous behaviourist from America as well.
So a really good one. Obviously, it is recorded. It is rather late, so if you want to go to to bed, it will be upper's recordings in the middle of the week.
So again, Sandra, thank you so much. Karen and John have obviously gone, but thanks to them as well. And .
That's been absolutely fantastic. It's been really, really interesting. So thank you so much everyone for participating.
I'm, I'm I'm delighted that people bother to try to answer. So good job. Thank you so much.
Take care and we'll see you, maybe on the next webinar but hopefully at some point anyway. Thanks, Sandra, bye.