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Principles of Deformity Correction for Orthopaedic Exams
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Principles of Deformity Correction for Orthopaedic Exams
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Language: EN.
Segment:0 .
Hello, everyone, and good evening, welcome to this joint session between our UK and orthopedic mentors group in preparation for the FRC exam. I'm honored today. I been joined by expert, lecturer Mr. Alex Trompeter for this principles of limb reconstruction and joint deformity correction.
Both groups are UK and orthopedic mentors group, or FRC as mentors group dedicated to teaching and educating you guys to pass the exam. We've produced many courses, books and seminars dedicated to the session to this target. Please join groups and follow us. There will be more lectures coming under both headings. This lecture itself is recorded and will be put on both websites, our website and the UK website, which you can look at a later time.
In the mentors group, we've got a telegram discussion platform where any questions related to this lecture or any other lecture will be discussed. If you want to join, it is record your interest and we will be adding you to arteriogram group for a later discussion this session. So we'll start with the introduction. Then there will be the lecture itself. If you have any questions about the lecture, just write them in the chat function.
We will keep a note of them and after the lecture, we will answer these questions after that. Mr trumpeter has got some case typical cases and how to answer them, which would be really worth your attention. Then the recording will stop and then we will have some private practice for you guys. If you are interested in the practice again, let us know by raising your hand and adding your name to the, you know, putting your interest in the chat, and we will keep a note of that.
We hope to finish at 930, but sometimes can overrun OK now. But lecturer today is an experienced surgeon. He's been doing limb reconstruction for seven years in London, in some St George's Hospital. Not only that, he is. It has passed the FRC exam, of course, but he has passed it with a.
Gold medal for scoring the highest mark, which is Walter Mason gold medal in 2011. He is as well the local. He is the program director for the Southwest London orthopedic program that makes them well equipped to know about teaching training and about what comes in the exam, so I would pay particular attention to today's lecture.
I'm really honored and without further ado, I've been talking too much. Here's Alex Trompeter. Thank you. I shall just light up my screen. That's the very kind introduction. Thank you to Luke and to the mentors group, to having me along today. It's an honor and a pleasure to be here.
I am going to give you an overview of the basic principles of deformity correction from the standpoint of what I think you would need to know and understand that in order to comfortably pass and Fox five a table, it is not the same as me saying I'm giving you an overview of all of deformity correction in an hour or a half an hour, and it's not the same as giving you a comprehensive course or skill set to go and perform these surgeries.
But it's about being able to understand and answer questions in a topic that can be a little bit daunting. And isn't something that everybody comes across during their training. These are my disclosures. None of them are relevant to this talk, but I have a breadth of involvement in education, so I thought I would break down what I think the ideal objectives for this should be.
And I've suggested that we look at understanding how to analyze a patient's deformity both clinically and geographically, then really look and understand the principles of correction and have a vague idea about how we might go away and go about correcting a deformity. And if there's time and I'm conscious of time, I do have some slides just on the basics of fine wire and hex upon fixation that might just be useful and a complement to the deformity component here.
So let's crack on and think, well, if we're going to assess and analyze a deformity, we've really got to understand the basic principles of actually how we go about that. We also need to understand what we would call normal, what is normal in the deformed limb and then a little bit of a system, if you like. And a methodology and approach for assessing a deformity, especially on an X-ray and then a means of planning a correction because this is absolutely one kind of surgery where planning is key and the planning usually is radiographic and needs to be recorded and documented in the records often saved into packs and so on, especially in this day and age.
With our medical legal culture ever changing, our record of our plan is going to be increasingly important. So what do we mean by a deformity? Well, truly, we're meaning the state of being misshapen and when it comes to the skeleton, what we're really talking about in the limbs. And for this, we're going to focus on the lower limb today, primarily in the femur and tibia.
We're talking about faulty alignment of the bone itself, which therefore has an effect on the limb axis or faulty in alignment and orientation of a joint. For a length issue, all of which are misshapen problems with the bone. And then those deformities can either be congenital or acquired simple or complex, usually meaning by complex. They often have a soft tissue component or maybe part of a syndrome or maybe multiple deformities within a limb.
They may have associated medical conditions. They may just be cosmetic and have no functional limitation at all. No impact on the patients daily life. Male union, which is probably a more common type of deformity that we will see in orthopedics, especially for those of us in a trauma practice and in an adult practice relates to faulty healing of the bone and failure of the bone to unite in such a way that the original normal axis of the bone and therefore the limb is not restored.
And of course, the impact of that may only be radiographic or there may be a clinical and functional component or the potential for a future problem. So a very small, aligned tibia that doesn't cause any symptoms or functional limitation now may lead to premature joint disease in the future. And so there's a consideration there to be had. Like all good things, when we come to assess the patient, we're going to need to consider the history, the examination.
And then the imaging and the history is pretty easy. From a deformity point of view, it's the usual suspects. Is there pain? Is there functional limitation? You've got to go in depth into that from an farke's point of view, if you're in a vyver situation, you may say I'd like to establish the patient's past surgical background, the history of trauma, their past medical history of Allen medications that may have an influence on surgery outcomes like anticoagulants, steroids.
And so forth. Many of those things, just as an aside, are all about having packaged answers in the farke's exam. If you've got here's an answer I give if I'm ever asked what operation I want to do, or here's an answer I give it a never asked how I assess a patient. You have this grouped packaged answer. So for histories, it's what's their past medical background.
Are they a smoker? Do they have any diabetes or other comorbidities that are influencing healing? Are they on any medications? I need to be aware of your show, an understanding of the importance of that in deformity, mainly from what we're talking about tonight, there's going to be a congenital problem, i.e. they've had the problem lifelong or it's an acquired problem, usually after trauma or similar.
And then what the functional impact is and what interventions they've had so far, if they've had a leg length discrepancy and they've not even tried a shoe raise yet, you may consider that before embarking on surgery. Examination really is relatively straightforward. If you get an examination in the clinical, there will be a huge amount to talk about primarily on observation first and foremost and using your descriptive terms.
We must look at the gait for the patient, usually in deformity, you may see things like various thrust in various limbs or a vagus. Obviously vagus gait in a more vagus knee and similar. You may see a short leg gait and therefore an issue with that they may be using walking aids or splints or shoe raises. You'll need to undress the patient to assess the scars and the soft tissue envelope, including in congenital and in acquired conditions.
So trauma there might be previous plastic surgery and so on. But in congenital, they may have some clear signs of the underlying pathology, and we'll come to that in some of the cases later. You'll need to assess them from the front, back and side. You'll need to do your tests for leg length discrepancy. Usually, the galaxy is my preferred test. And you must examine the joints for range of motion and for stability, and that's incredibly important, especially in acquiring congenital deformities.
And we mustn't forget the rotational profile and the neurological and vascular status of the limb. Rotational profile assessment is really key. There are some very good descriptions in the femur, we're going to look at the difference in rotation from one side to the other. The tibia is sometimes a bit harder. We can look at things like the foot progression angle. Actually, I do it with the patient prone and bending the knee up, but this is a similar net result.
This is pretty normal on the patient's left. On the patient's right. Here, you can see the foot is externally rotated to about 50, maybe even 60 degrees. And that clear external tibial torsion there. We're going to come on now to the real meat of the issue. What I've sort of thought probably everybody wants to get from tonight, and that is how are we going to assess and plan deformity correction?
One of the most important things in deformity correction is ensuring that we get proper imaging taken in order to do proper planning from it. You cannot plan osteotomy of the limb about the knee or four focal knee X-ray. You have to have long standing alignment images. You cannot plan off X-rays if the patient is male positioned and the X-rays aren't orthogonal. So there are some golden rules of deformity correction.
And the first two really are long. Leg imaging must be taken with the patella pointing forwards, as you can see here under my cursor, and not with the patella pointing sideways. Because that will be key for showing you partly rotational profile issues, but also the appearance of varus and valgus magnitudes change depending on the degree of rotation in the limb as you hold it in one way or the other.
So it's really important we understand that. And then similarly length issues can cause apparent variation Vargas of limbs if you don't stand the patient on blocks. So again, it's really important that you stand your patients on blocks and level the pelvis when it comes to imaging. If you don't believe me, here's a case I just found in my X-ray bank. From the other day, this lady came to me with a tibial torsion issue on the left of your screen.
You can see it's the right leg. We're looking at this. Here is the patella pointing forwards, and you can clearly see she's got a rotational profile abnormality because we now can't see an AP of the ankle. The foot appears to be pointing sideways when she points her feet forwards. She's got a patella that's now internally rotated. She has an apparent Vargas of the limb, and you get a really different picture of assessing her deformity.
So you've got to be aware of that. If you're lucky, the radiographers will take both sets for you or if you know what you're getting, you can ask for both sets and they will tell you how they positioned the feet. The next thing is then understanding the way and the methodology that we use to assess the limb from a deformity point of view.
And this comes back to understanding the axes of the bones and that's of the bones, not the limb at this point in time. And we'll come to the overall test in a minute. But broadly speaking, we can use the mechanical axis of a bone to measure things or the anatomic axis of a bone to measure things. But what we mustn't do at any point is interchange our choice.
Once you've set your sights on one, stick to PM until that case is finished, because if you muck them up or interchange accidentally halfway through, we'll have trouble. Anatomic referencing refers to what anatomic assessment and planning refers to use of the anatomic axis of a bone, which is defined primarily by the midpoint here of the width of the dialysis, as seen on an X-ray.
It is the width of the cortical bonus in an X-ray. It's not the width of the canal. It's not the width of the bone itself as a whole. On the tube, it's the width of the bone seen on an X-ray. And remember, not all bones are perfectly round and you take two points in the dialysis. And the midpoint of those two lines across the dialysis gives you an extension up and down what usually is the canal or canal light area, and that's the anatomic axis of the bone.
Your mechanical axis is taken from the center of the joint above to the center of the joint below. So they are wildly different. An angle formed with the joint at each end of those axes gives you your, for example, distal femoral angle here lateral distal femoral angle or your medial proximal tibial angle. And they are prefixed by either an A because you use the anatomic lateral distal femoral angle planning method or an m because you use the mechanical lateral distal femoral angle method.
And if you look here specifically for the femur, more than anything, the numbers are very different. The lateral distal femoral angle in anatomic and axis planning is 81 degrees. The mechanical lateral distal femoral angle is 88 degrees, so if you interchange them, you'll suddenly introduce a difference of 8 or 9 degrees in your assessment and you won't know where it's come from. Just as a pictorial representation mechanical axis, central joint above to below an atomic axis mid-point of the width of the apparent bone width on X-ray through two points of the dialysis center.
The tibia, the mechanical, inner and almost overlying. There's actually two to three Mils difference. The femur, as I say, very different indeed. Just just zooming in Allen again a little bit more and you can see in the tibia, they're not quite coincidental, but we can assume that almost one in the same. But the FEMA incredibly different. So once we know how we're going to or which method we want to use anatomic or mechanical, we can now start to go and assess the radiographs fully.
And there are some steps in which we should go about things, because not always is a deformity obvious. Not always is a deformity single, there might be more than one. And if there is an obvious deformity, I clinically it's not always obvious where it is geographically or it's not always where you expect it.
So we go through a series of steps of assessing things in order that we don't miss stuff primarily. And first, we do the alignment test. Then we do the male orientation test. Then we can look at each bone individually and then we can look at all the different planes for that bone. And then finally, we can come to defining where the deformity lives, which we'll talk about in a second.
So the alignment test. Is a test essentially of the weight bearing axis of the limb and in the lower limb, we're talking about the axis from the center of the ankle to the center of the hip, and we're familiar with this generally, if anyone's ever done a knee replacement or a knee job or any of those sort of things, you look at this quite a lot. And this malalignment test overall is a really good quick test of telling you, is there a deformity or not?
We normally see the weight bearing axis of the limb pass just medial to the midpoint of the tibiofemoral joint AM here. So that's a good overall screening test for is there any problem with an alignment in this limb as a whole? Sometimes the length issues don't really demonstrate a Big Mel alignment test. Sometimes complex double level deformities or deformities with translation as well may not show a malalignment test is positive, but it's a good place to start.
Next is the male orientation test, and we come back to that understanding, then of which axes we're using to assess the bone because we need to look and see where our joint angles are and whether therefore the joints are orientated correctly at the end of each bone relative to its axis. Hence, male orientation test. And that means we need to look at the proximal femur, distal femur, proximal tibia, distal tibia, and we'll look at the classic.
And for most folks there, will you be looking, for example, at the medial proximal tibial angle? 87 degrees? And we know that through the access to the joint. So there's a three degrees of inherent virus in the knee and the distal femoral angle, usually either 88 mechanically or 81 laterally and 81 will be familiar again to those of you done knee replacements with interim medullary femoral referencing.
And we'll come back to that in a second. And you just need to broadly that there's about 9 degrees of Vargas from the anatomic axis to the joint line. You can also look at the joint line convergence angle here, and that tells you you've got an intra articular deformity or not if the joint converges on one side or the other. So that's a male orientation test, and it's really important because if one of these angles is wrong, it normally tells you there's a deformity in that bone and towards which end of the bone it lifts.
So you're starting like a detective to unmask where the deformity might be hiding. And you therefore need to know these numbers, or at least have a chart with these numbers to understand what's normal so that when abnormal crops up, you can pick it out. Just say you understand why the media proximal tibial angle is at 87 degrees, OK, because when we single leg stance, which is what we do most of the time when we're walking or anything, we add ductile leg to underneath our midline.
So our weight bearing axis of this limb shifts to be under the central axis of the human form, which means that our joint, which was inherently various, slides around to being neutral and parallel to the ground. And that means you lose that three degrees of varus of the joint single leg stance. And that's why if you've ever wondered why your knee components are also rotated by 3 degrees as well, there comes to accommodate that three degrees of varus in the tibia at the medial proximal tibial angle.
So that's why there's that mystery three degrees of rotation in the knee replacement component placement. And it comes from this. So that when you flex your knee, you go back to 90 degrees in a flexed position in your replaced knee. So we now understand that we might have a mal alignment, we now understand that we may not have a male orientated joint.
We've got to then start to look at the deformity in a little bit more detail. Now, of course, life isn't straightforward and deformities don't ever appear in Just the frontal or sagittal plane. Actually, deformities usually in the oblique plane or deformities, unless they're double level or sort of complex with rotational. But a single plane deformity always sits in one oblique plane now that might be in the coronal plane, but usually there's some way around the clock face where you'll see the deformity only in one plane, and that's oblique.
But of course, we don't get our x-rays taken in that plane. We get our x-rays taken in the two cranial and sagittal planes. Deformities may also annoyingly be located in the joint, or they may even we will come to this. This is where the head scratcher begins not be located inside the bone at all. From a mathematical standpoint, and that is a really crazy thing to understand and is a really important thing to understand when you come to correcting a deformity.
Now, if we look at these X rays, we can start at the top left, these are not x-rays or these schematics. And if we look at this first picture on the top left, we've got a malalignment test here. This dotted line, if you imagine you're looking at X-rays here, but has told me that we've got an issue here with weight bearing being shifted over to the medial side. So I'm thinking, oh, there must be a deformity here.
And then in this example, we look on the medial proximal tibial angle is less than 80 85 degrees. That tells me the deformity is probably located in the medial proximal in the proximal tibia here because the male orientation test has identified an abnormality with this angle. Similarly, same alignment test here, but we've now got an abnormality because our lateral distal femoral angle is increased.
So we've got distal femoral virus leading to the same net result as medial proximal tibial virus. And you could indeed have a combined leading to an even greater deformity. Similar in the distal tibia here, here's a malalignment test now when the joint deformity is over in the proximal femur or the distal tibia, the effect on muscle alignment is less.
Then if the joints around the knee, because your weight, your center of your joint doesn't translate very much compared to with a knee joint deformity, and here you've done a male orientation test the distal tibial angles not right. So the deformity is located in the tibia, probably towards the bottom end. Again, here, similarly in the FEMA malalignment test is pretty, pretty reasonable.
But the male orientation test has shown a big various male male problem in the proximal femur. And then similarly, we can have issues with articular deformity here. So this is really showing you right up in the joint here with a joint convergence problem and then this pattern deformities here. So we've kind of established where we think the deformity might live geographically.
We've taken a history, we take an examination. We've got beautiful standing, long legged views. We think we've identified there is a deformity. We think we know where the bone is that's involved in it. Now we've really got to work on describing the deformity in a mathematical way so that we can treat it with accuracy and provide the patient an outcome that is an appropriate mechanical solution for their mechanical problem.
You can't just sort of look at the bone and go. It looks a bit jaunty. I'm going to hit it with a hammer till it goes wobbly and then nail it straight. It does work occasionally, but it's not very good from a documentation point of view. And if you get more complex deformities, that's a bit of a problem. So that approach only works to so far.
So the corer, the center of rotation of angulation, OK, not the center of rotation and angulation, the center of rotation of angulation and the language is important because this tells you the point about which the deformity is located, such that if you rotated the axes of the bone at each end around that point, the deformity would disappear, i.e. it's the point of angulation about which things have rotated.
Now let's just break that down a little bit further. Whenever we assess a deformity, we need to pick an axis of the segment of bone. Either side of where we think the deformity is living now for ease and so on. Here is a deformity living in the middle of the tibia. OK we can take a predictable axis up and down the tibia because we know from what's normal, what we saw at the beginning, what these magical joint line angles are.
But when you plot the joint against the Axis of the bone, it is a predictable number. So we know that the lateral distal tibial angle. So a line between the axis of the distal tibia and the tonic and the joint surface of the distal tibia forms 89 degrees. And I know that the medial proximal tibial angle align across the joint and a line down the axis of the proximal segment form 87 degrees. Therefore, we can extrapolate these lines down on the axis of each segment of the bone and where they cross is the chora.
OK go through that again, because this is key. Joint line at the top and atomic axis at the top angle between the both normal 87 degrees. Same at the bottom and atomic axis joint line normal 89 degrees. Take those lines up through each segment of the bone till they meet and that there is your chora. And if you look at this with your mind's eye, if you imagine cutting the bone here, sticking a drawing pin in the page and rotating around this point.
And we did this with our bent bone. Everything would line up. What's important to realize is that sometimes where you think the deformity lives, like here in a big blob of callus is not where the deformity lives because mathematically axis of the bone relative to the joint axis of the bone relative to the joint, the core is here, and that's where you would need to rotate your angulation.
In order to get rid of the deformity, if you stuck your drawing pin about here where you think, oh, here's the blob of callus, you wouldn't correct your deformity, you would induce a translation as well. I'll show you that in a minute. So here, just so we go a little bit further malalignment test, right?
Bones not normal. Male orientation test, ok? Distal femur, pretty normal, proximal tibia. Very abnormal. We'll use our joint line, and it usually for purists sake, you might choose to use actually the opposite side of the joint and extend it as opposed to using the proximal tibia. But the same net effect anatomic axis of proximal segment, anatomic axis of distal segment.
And that gives us a chora with a magnitude of 30 degrees, i.e. a deformity of 30 degrees virus, in this case in the distal tibia. Do the same in the digital FEMA or the proximal tibia all around, so mammal alignment test mechanical axis deviation shown. Normal hair in the distal femur, laterally abnormal in the medial proximal tibia. To measure it and look, Lo and behold, the deformity is right up in the proximal tibia, almost in the joint.
And that has a special implication when it comes to correction. So when we look at that again, just say, you know, the deformity can be obvious. It may not be obvious. As we said, it may not be at the same level as a previous fracture. It may live outside the bone or even in a joint. And here are just some examples of where you can get caught out.
This is really important shows the importance of two views. These are all my own cases. Here's a femur left femur malunion sent to me because of medial knee pain, and they were a bit early for a knee replacement. And you look at this and you take a really close look and you can measure the core here. And you can work it all out and then you take a lateral X-ray and they have another deformity, but disappointingly isn't located at the same level on the AP and a lateral.
And this deformity isn't really located where you think it is. This deformity is located about somewhere up here on the lateral. If you think extending your axes of each bone, this deformity on the lateral lives pretty much in the hip. This deformity lives in the middle of the femur. To correct both at once, you need to think, how are you going to overcome that? He has a proximal tibia, male union, and you can see here, this very clearly is going to be living around here and we can do our orientations, and that tells us that the core is indeed pretty much bang smack in the middle of that zone of fracture, which wouldn't be surprising because it's not really healed with much in the way of translation.
It's just healed with angulation. And then here we've got a medial proximal tibia fixation, malalignment test, so this is central joint above to below. These are all done on trauma card tells me that the weight bearing axis has shifted right over medially. Here we can go for our male orientation test, and here we can see that the axis of the distal tibia and then an axis coming down from the proximal tibia.
Tell me that my joint, my deformity is located here at 7 degrees in the joint itself. So the core here is located right in the joint, which then means you've got to think, how can you correct this if you can't stick your drawing pin in the joint to correct your bent bone? And then we've got a planning for correction, where we can show we can get the limb straight. And this is a great way of recording your documentation of how you've correct thumb your correction before you've even done it, from a notes and records point of view, and I'll talk through this in a minute.
OK, so that's part one, how we assess deformity. I better crack on because I'm conscious of time. I'm going to go through how we correct deformity, and then I will probably see how, if the time, if I do anything on the frames. So there's a bit of a language issue here. This bit. Don't get too worried about, but broadly speaking, a corer is actually not a point in space.
It's a cylinder because a hinge can be infinitely long about which if you rotate, you could still get the same result. But broadly speaking? You can put a any, anywhere you like. The core for the deformity is defined, as we said, mathematically here. If you imagine there was a 3D dowel going across the screen, not towards the screen, you could choose to pick anywhere along that if there was a 3D dowel going through the screen here.
All of this would be one corer infinitely in any distance, because if I rotated about my 3D rod in this plane, my deformity would correct. In this one, it's different. The apex of correction of angulation is broadly, in many ways, the location of where you choose to pin your correction about. So where you choose to make your hinge to correct your deformity.
The chora is defined you can't change the core of the core is defined mathematically. You can choose your point of rotation for your correction. That's not the same as the chorus, so you can choose a point of rotation for your correction, but you cannot change the anatomic location of the chora from maths. You can choose where to put your osteotomy. And your point of correction.
Hinge, the point you choose can be or cannot be at the corner and you osteotomy can be and cannot be at the corner. And those two things that you have choice over where you put your hinge and where you put your osteotomy lead to different results, depending on what you do. And these are called the osteotomy rules. Osteotomy, rule one.
Essentially says you choose to perform your correction where the camera is located. And you choose to perform your osteotomy through the chora. This is the ideal for making a bone straight. If you look at this picture and ignore the three dots, just look at the. This is the core of this axis and this axis in this segment of bone. If we choose to cut the bone across here.
Ignore the little wedges for the moment, which is to divide the bone and rotate about this central point or two axes will line up. And our deformity is corrected by virtue of choosing a point of correction at the corner. And an osteotomy through the chora. OK, that is a rule one, you can do it via closing wedge and you can do it via an opening wedge. But broadly speaking, you've chosen to put your osteotomy at the corner And your hinge at the corner.
Everything goes straight afterwards. You could choose if you wanted. Too, is the deformity same picture? Bent leg two axes, just look at the middle dot. We've chosen to still put our hinge here or chosen point of rotation, but we've cut the bone away from where the deformity is located. And we're now going to rotate the cut piece of bone around the hinge, so imagine this bone is still long enough that it lives up here.
There's a virtual piece of bone and this piece is rotating around this point. What on Earth would we do that? Well, this is what you need to do when you're deformity is located in a joint, because clearly, if your proximal tibia is here, I can't cut you through your proximal tibia and swing it. We have to cut you in the tibial metathesis and divide the bone there.
But we can still rotate about the actual location of the deformity. The net result is you get a bump. And depending on the magnitude of your correction and the distance between the point of rotation and your osteotomy, the magnitude of the bump would be decided and sometimes it's not a problem. So we quite often see this, for example, in a fibular osteotomy when we're busy correcting the tibia because the fibula is not at the point of rotation.
So you'll often see a bump or a problem with the fibula afterwards. They often heal or it will smooth off. Or sometimes you might need to go and shave off the bump. You also need to ensure you have enough contact on this side for healing. So that's rule two. You're going to rotate at the corner, but you're going to cut the bone away from the corner.
No prizes for guessing rule three. Here is your deformity. Here is your chorus. Still, this time we're going to choose to rotate away from our chora, so we're going to pick another point in space to make our hinge. Am I going to divide away from our Cobra and look what happens? We induce a translation.
So our axes do not line up afterwards. This is usually unintentional. This is usually not desirable. There are very few occasions where you can use this as a clever way of treating two deformities in one bone. Don't worry about that for now. All you need to know is this rule one. You're correct at the corner.
You divide the bone at the core rule to you. Correct it the corer. You divide the bone away from the corner and rule three. You do not involve the core in either of your choices. It's really that simple. Just one last schematic, so you can see in rule one, the axes stay the same. In rule two, the axis stays the same, and in rule three, the axis translates.
Dame osteotomy, some of you may have come across this hour rule tos, you're going to take your corner, you're going to rotate about your corner, that you're going to divide the bone away from the corner and give yourself just more bone contact. It's just a way of giving you more bone contact and reducing the presence of a bump. That's all, but it's still a rule to correction.
And a note on osteotomy says this is a surgical division of the bone. The aim is to try and recreate and promote fracture healing. Meeting you lots of different ways you can do compression osteotomy, you can do opening wedge, closing wedge, you can do distraction osteotomy, all of them need to preserve biology in one way or the other, in an ideal, especially.
So if you're going to be growing new bone in the gap. Um, I've written a paper this is actually a shameless plug, but we wrote quite a nice review of all of the different ways of dividing a bone. And it's a fairly easy read. I think it's free to download. If not, I can share it with you guys afterwards. But this I hope the guys up in Liverpool and just goes through the different methods of dividing a bone and the pros and cons.
My preference is a drill, an austere team. So here you go. Some drill holes and then we use an austere tone to join the dots, and that gives us a pretty neat osteotomy. Here's a dome osteotomy to be created. So we can use a half pin at the corner and rotate a Rancho cube around. And that gives us a series of curve drilled holes that then gives us a curved osteotome for a dome.
When we come to correcting, we need to choose whether we're going to correct acutely by one or gradually, and that will depend on several things. The soft tissues dictate it. So the classic is a vigorous tibia with a lot of scarring on the medial side of the tibia going to Vegas. You can't acutely correct because the soft tissues won't allow it.
You'd have to do a flap or something at the same time. The other one, a classic, is internal rotation to external rotation of the external to internal rotation of the tibia. So big rotations of the tibia and pulling on the perineal nerve acutely. The patient may not like it. They may get certain pain the size of the deformity. Acute rotations of the tibia over about 30 degrees 20 30 degrees are quite hard to do acutely.
You might have associated lengthening, and therefore you'll need to be guided by you're lengthening rate. You might not have the skills to do acute corrections accurately. You might only be able to do them gradually. Gradual correction, obviously, usually with a frame. And then implant choice, you can do internal works well for acute correction external usually works well for gradual.
You can do acute correction with external, so do it on the table. But you might be worried about the soft tissues or there may be lower infection risks and similar just by using a frame. And then we can use the benefits of external fixator and their accuracy to do a correction, but then replace them there and then or you maintain the reduction with your fixator and then employ internal fixation on the table there.
And then and then take away the fixator at the end. Then they get the best of both worlds. They get a fixator assisted deformity correction. You can use a hacksaw pod that's called chaos surgery, computerized hack support, assisted orthopedic surgery where you do the deformity correction using a fixator. Slide your plate or your nail in. Take the fixator off.
Hey, presto, accuracy and internal fixation all in one go. If we're going to go and do this with a Elisa of frame and we're talking about frames here because I don't need to spend time telling you about how to use a plate. We just need to understand a little bit about how the tools work and how we can use them for what we've been talking about. I'm from a mechanics point of view, just to remind you, plates and multilateral fixtures work on the off axis fixation and/or on the cantilever loading.
So that's just sort of diving boards. Your suspended your cantilever roofs, so they're fixed at one side and cantilevered at the other. They lead to an isotropic loading of the bone in the implant, which causes potential problems with healing and lysis and so on. Implants that are located about the axis of the bone are what we call on axis or beam loaded, so that means they're supported at both sides and nail is being loaded.
It's just very short beam. The frame is clearly being loaded if you're using wires, not half pins, and that gives you a much more even isotropic loaded device. And those of you coming up to the Fox should know those terms. Isotropic anisotropy inside out. In the frame, the beams of the wires, not the rings, so the beams of the wires, not the rings.
And the wires are under tension, just like your. These things, what you need to understand is that something can be inherently very weak, very floppy when it's not loaded under tension. A wicker chair, for example, the wicker chair is made of grass. Grass is not very strong stuff. I can slap the blades of grass in my lawn quite happily. Tennis rackets are strung with cat gut. Historically, that is floppy stuff.
Trampolines, anyone who's put one together, we'll know when they take the mat, out of the box. The mat is floppy and hopeless. I've never built a suspension bridge, but I imagine the cables are quite floppy before you string them up. The unique thing for all of these here is all of those things are put under detention. Your cat gut is strung tightly in your channel racket.
Your trampoline has about 150 Springs around the outside. Your cables on a suspension bridge are pulled taut. Your chair of wicker here is pulled taut, and as soon as those things are pulled taut, they support load. Just like your clothesline, you string your clothesline loosely between two poles in the garden and your clothes will hit the floor, but you pull them tight. And that clothesline, the same clothesline went under tension will support several pairs of wet jeans much, much heavier.
So as an object under tension will resist resist load and decimation. And that is the principle of how the fine wires work. So they are very, very good in terms of supporting the limb with a very small biologic footprint. We also, though, need to understand how we can apply them to a bone for deformity correction purposes. There are several components just to refresh you.
You have wires. Olives are not the olives here. They just add some stability there. Bayonet tipped we have rings usually complete or two half rings join to make a complete ring. We have elements to join the wires to the ring. And those of you that do frames will know you should always build to the wire and not pull the wire to you. So the wire crosses the middle of the hole.
It goes through the middle of the fixation. If it goes to the edge of the hole, it goes to the edge of the fixation. If the wire stands off, we use washers or even drops. Half pins are clearly cantilever structures. There are all sorts of types. Generally now more modern day ones will be coated for deformity frames and just plain for temporizing external fixator.
They may have self-cleaning tips. They may be smooth tip. They may be conical. You need to these sort of things for describing implants, and they have to be able to be captured to the ring one way or another. You need rods to be able to join your rings together. And you can use certain devices to make the rings get further apart or closer, that might be for a lengthy, and we can also use hinges in the frame to allow us to take a bent frame and slowly straighten it, which we might want to do with a deformity correction.
We need a lot of nuts to put it all together. Generally, two rings per segment of bone, two wires per ring near far fixation gives you a stable construct. That's a very simplistic view of a laser oral fixation, but it's a reasonable start for those of you that don't know it and you maybe get past one in the exam, you could say that much and you'll be fine. In order to do a correction, we're going to use that same method of analyzing by applying our frames, so we talked about referencing or the alignment of the axis of the bone relative to the joint at one end and the alignment of the axis of the bone relative to the joints at the other.
Well, if you put your frame on a bone with it aligned to the joint at one end and the line to the joint or the other. If you've got a broken bone and you do that, the bone will straighten at the end of it. And if you've got a bent bone, then you'll be able to bend, frame together and then break it and straighten your frame. You'll have a straight bond.
So if you have your frame reference to the joint above and joint below, you will have a straight bond at the end of things. this is what I mean. This wire here we go referenced to the joint above. This was a reference to the joint below. And then Lo and behold, you put a frame on it like this is an acute fracture, but the leg is straight, not difficult. It's aqueous or K wires and a bit of maths. So anybody that thinks that a Lazaroff surgery has some mystique, it's actually OK.
We can reference and just remember if we're going to do that anatomically or mechanically. So here's our wire. Just remember we're doing that. We've got to understand which reference we're referring to in the femur. If we're going to do our planning with this, we need to understand, as I say, coming back to where our core lives and where we're going to correct through, so let's say we remind ourselves of our osteotomy rules.
Type one so we've got a osteotomy here. We're going to end up with a osteotomy and the hinge at the level of the deformity. Here's an example. Here's our deformity. Here's our hinge. Pretty much on the line of our deformity. We can divide the bone with reference to our frame. Approximately here I'll frame distally here to the joint.
We divide the bone, we straighten the frame and the bone straightens. OK, that is the principles of using an laser frame for deformity correction you can manage. Increasingly, complex deformities within inches are of frame double levels. Here you go. Lots of different bets. You can even rotate by offsetting the rods relative to each other.
The problem with it is the more complex, the deformity, the more complex frame, and at some point, the frame becomes a manageable for both surgeon and patient. Say, wouldn't it be nice if you didn't have to really think about any of that? And you could address all of those things in one go. And that's what a pod does. It's still in Israel frame. It still tackles the issue of fixation to the bone and the biologic aspects and so on.
But it's taken some of that thinking and planning away from us. I think the analogy is a bit like a computer assisted joint replacement. You probably still need to know how to balance a knee replacement properly. And if you're going to use a pod, you probably still no need to know how to do proper deformity correction, but it just means you can tackle a more complex deformity in one go.
It is based on what's called the Stuart golf platform, which is a octahedral area in space divided by 6 adjustable lengths, so six struts to platforms. These are typically seen underneath flight simulators, and if you move any one of these, the whole geometry of all of the triangles created between each set of struts changes. Which is used by Nasa for docking the space shuttle into the International Space station, so we think about how you move to things in space relative to each other.
They have a virtual isopod between them telling them how to change the length of each relative vector to allow the space shuttle to dock. It's super clever. If you're a space geek like me, you'll love this stuff. So a pod is just that the two rings with a laser of stuff at each end, joining to the bone. And this six piston movable beast in the middle that can allow for the movement of the bone in any direction in each segment relative to the other.
So it is the movement of two wings relative to each other in space. Each segment of bone moves with a ring, so you'd have two rings here. A segment above a segment below the six struts usually have a predictable attachment to the rings. And it allows movement in all directions. So you can have axilo translation here, the struts will get longer.
You can have horizontal translation where we see the struts move in certain directions for some struts, so this strut, for example, will get shorter. This strut will get longer as you move things away. You might be able to correct an angular deformity and you can correct rotational problems. And of course, you can combine all of those into one prescription so that all deformities are addressed in one go by the computer.
That's the benefit. For a frame, you need struts, usually six of them, they have to go in the right place and there's non-negotiable. And you can put them the frame on to match a deformity so you can plan in advance and build a frame that matches your deformity so that when it's correct, the frame is neutral. That's quite a nice and elegant technique.
You can acutely correct a frame so you can undo the wreckage struts in the middle. Same on the TSF, same on the tail hex. And for example, in fracture surgery, you reduce your deformity and you can gradually do it. And it's basically an Elisa a-frame with specialist instrumentation in an octahedral six axis support, as I said, with a virtual hinge in it. That's the difference between a pod and an illiberal frame.
Nothing else. It needs a bit of software and in principle, just a couple more minutes before we get into our cases. But in principle for the software, you need to be able to describe the deformity. I tell the computer, what is the deformity you need to describe to the computer, the shape of your frame and the size of your frame, and you describe to the computer how that frame is related to the bone.
You also tell the computer what you'd like at the end. Usually a straight bone, please. And over what time frame? That's all. So define the deformity. You find the frame shape and the relationship between the two. Defining a deformity, we use the software on the computer, right long bone here. Here's a deformity.
This is an acute fracture at about four weeks down the line. They've had the flap now, the joints being fixed. We've got a shaft that's been a bit shortened, so we're going to measure it with the frame on now. There's some translation immediately by a centimeter. There's some translation posted by $0.2. Whatever the numbers, there's a bit of shortening. So we can put this in to the computer telling us that there's a deformity.
Usually they give you a dowel representation of the deformity. So a picture showing you and you can look at that and your x-ray, is that the same? OK, good. I've got my deformity measured, right? So you don't sort of make a mistake. Then you're going to tell the computer what the frame is like.
So in this one, we said, oh, we got 160 rings at each end. We've used a load of long struts. These are the settings on the strut. So the computer now knows the shape of your frame because the six stripes always go in the same place and then you've got to measure the frame and how it's related to the bone. So that's usually where the middle of the frame is relative to the middle of the bone, so it's a bit posterior to offset.
And so on. And then you get a picture of your deformity with the frame on it. And remember, in our picture, going back the bottom ring of the frame is pretty much at the level of the joint. So the bottom ring of the frame here is at the level of where our two dials are meeting because the bottom of the joint is here.
For those of you that are really interested, tell hacks and measure things differently, I'll skip past that. You don't need to know that. And then at the end, you just find your time scale and that's based around the rhythm and rate of correction and any latency period. And then the patient usually gets a prescription that tells them how to adjust each struck each day, such that the correction is undertaken.
And then you finish with a leg now of the look that the tibia is the tolerance is under the tibia in both planes because we've used the computer and it's told us how to address these struts to gradually move the bone back into place. And that is the use of a frame in deformity correction. I suppose there that I think is enough forever. It's not for me for a lifetime, but I'm sure that's probably still some brains up and maybe has generated a question or two.
Thank you very much. That was really, really interesting, and I enjoyed every bit of that. Congratulations on this really interesting talk. Fine so far we haven't got questions. I think everyone was just focusing on concentrating on what you are saying just to give the guys time to add questions. I will use this time to remind people of a couple of important things.
First of all, for your questions, please, please write them for everyone, address everyone in the chat function. If you have any questions, please write them down and we will answer them. The second thing is, we really appreciate your feedback, guys. All our UK will be sending you a feedback form. We really appreciate if you feel that it'll teach us how to improve and it'll, you know, it is your way of saying thank you to all the efforts that has been put into this lecture.
Please keep looking at the UK website and arteriogram group. We will tell you of the upcoming lectures. We've got one next week and are coming to the exam. We've got the five hour session today. It will be a short one because of the time. But if you are interested, please let us know. We've got a frequent online webinars Viva exam sessions. I think the next one is coming in October, around the tenth of October.
There is another one coming after that, so let us know. And these, I'm afraid, because the spaces are limited, they will finish very, very quickly as in the spaces will fill very quickly. So please let us know as soon as the other thing is a couple of, you know, really nice books for the exam. The UK have produced two books one Viva and one multiple choice question. I believe they are very, very important.
I used both of them actually for the exam and we've got our own mentors group concise notes for Orthopedics. Again, I would recommend it to everyone. It is very, very concise, and everyone who has used it found it useful. OK, the first question is. Uh, especially in the lengthening, in respect to mechanical access.
Wouldn't that create a new deformity? So I think, yeah, I had a look, this is a sort of two part question, so explain the lengthening of the female with respect to the mechanical and anatomic axis. And is there any issues with either? Obviously, the FEMA has two axes. And if we go back to the understanding, if you get longer, you need to be getting longer and access.
So if your implant for lengthening is based off a mechanical axis, when you get longer, you may induce a vagus deformity in the femur because you're going to be shifting downwards, not along the anatomic axis of the femur. So generally, if you're going for femoral lengthening, anatomic access is preferable generally nowadays for me. Anything femoral or lengthening? Indeed, most lengthening I do with an interim medullary lengthening male, which means that you remove the issue very much so of inducing unwanted deformity, especially over longer distances, because you're staying on an interim medullary device.
OK, thank you. So another question about what the concept of 3 point fixation in applying the bends. I'm not sure I really understand the question the 3 point fixation for the pins. I think what we're really meaning in terms of fixation with the frame is that any fixator, any frame device would ought to have at least two rings per boned segment and two fixation points per ring.
A wire is fixed at both sides of the ring and then goes through the bone with probably you'd think almost like a 1 broad point of fixation a half pin. We would try and use halves pins to be with as big a crossing angle as possible. 3 point fixation doesn't really apply with pins in the same way in pins. We're really talking about crossing angles to give us stability more than anything.
OK, so another question about if you can explain again, the Mayan alignment test and importance of joint orientation angles, please. So it's really important because obviously not all deformities are located in the dfacs or metaphysics of bones and the alignment test and the male orientation test help us just know if there's a deformity and roughly where it's located, but we then need to go a bit further and a bit deeper.
The joint lines relative to the axes can show us if there's a deformity towards the joint, but there may even be a deformity in the joint, and that may come just from a mathematic location. Like I showed you where it's because there's a translation or it may come from intra articular pathology. So in a very Vargas knee or in a hypoplastic lateral epicondyle or knee arthritis, those all cause deformities in or very close to the joint from pathology there.
So it's really important that we look carefully for where the deformity is located. So that we understand how we're going to overcome it and correct it. And sometimes it might be need to use an arthroplasty, or sometimes we choose an osteotomy like an FTO for a classic knee. Fto is really treating intra articular osteotomy with a or intra articular deformity.
Rather, with a rule to correction, you are taking an osteotomy and the metathesis to treat an intra articular deformity and pathology by shifting their weight. So it's really important we understand how to assess and analyze where the deformity lives so that we know where to offer treatment for it and how to treat it. Very good, thank you.
So a question about what is the biomechanical principles behind this deduction osteogenesis? So that's a whole other lecture. It's a distraction, osteogenesis is the formation of new bone under tension. It depends. It relies on tensile forces leading to bone formation. We know that bone responds to the mechanical environment around it.
We're used to thinking of it in compression, in fracture healing. But actually, most of the original work looking at fracture healing and bone healing and non-union management looked at tension. If you look at Lazaro's work, the original, the order of treatment was the nonunion was for distraction of the nonunion, and it increased tension, which increased stability.
Distraction osteogenesis is the creation of new bone in a surgical bone division. And by applying the correct rate and rhythm of that distraction, you will create new bone in the gap. I think it's a really big topic and probably one for another day or another talk. OK, so just a small question regarding that when you will remove the frame after achieving the required length lengthening.
Mm-hmm So when do you do that? Yeah, that's a really difficult one. So obviously you need to balance taking the frame off early enough so that the patient doesn't dislike you anymore versus keeping it on long enough that the bone is solid. And the typical time frame for a creation of new bone and distraction osteogenesis is generally one to two weeks of latency.
So that's before you move. Yeah, then the period of lengthening, which is usually at 1 millimeter a day and then a period of consolidation, which is usually at least twice as long as that, all again. So it depends on the size of the gap to how long the frame is. There are techniques now, which we can use, like plates off the lengthening or nails off the lengthening where we can do a lengthening and then change out internal fixation before the regenerate is consolidated.
Or we use an interim medullary device so that they don't have the issue of a frame at all. OK, thank you. What do you mean by the rest in frame correction? What do I mean by the rhythm? So the rate is the amount you move the bone in a whole day and the rhythm is the amount you do divide that whole day into. So anybody who's done an hour of frame will know that there are some lovely square nuts with dice numbers all the way around.
One two three four. And a full rotation of a nut is millimeter of travel on a rod. And the reason you have one two three 4 is you can divide that one into four equal increments six hours apart. That's a full day of correction because that allows you for optimum bone formation in the gap. And that's probably down to the cell cycle. If you go all the way back to your pre-clinical sciences at medical school and you'll remember there's a division phase and a resting phase in the cell cycle.
The cell cycles by virtue of giving them a rest and then distracting and giving them a rest and then distracting, you're probably influencing or matching the cell cycle in that process. So that's the rhythm. OK, so I think there's a last question, so is there is any difference in the principles of deformity correction for congenital deformities, degenerative or post-traumatic?
No, is the short answer and not in the principles of correction, the principles of assessing and managing the patient are sometimes a little different. Congenital deformities often have associated problems with joint laxity or other structures not being normal, not just the bone degenerative deformities. You need the difficult question around usually whether the patient has the ability to undergo deformity correction, whether it's in their interest, or would they be better served with joint replacement and then post traumatic.
Usually, as I say, is much of what we've talked about today. OK, so the last question, so now so what is the reverse dynamic technique in the frame? So there's reverse dynamic, so there's the idea of, well, there's two parts to reverse dynamite. So there's the tension and compression components of whether you apply tension or compression. But also then there's some really interesting work from Kenwright many years ago about the idea of being loading early and weight bearing early and then ultimately coming off something later as the fracture gap gets narrower and reducing load to reduce the strain in the gap and for healing.
It's a really complex thing dynamite as a whole. I tend to not do a lot of I dynamos my frames at the very end to see whether I think as a test to see whether the bone is United. I generally prefer to build stiffer, rigid constructs that I have more control over than the looser, dynamic constructs because I think that there's a little bit of more control from my side. But it's again another big topic.
OK, thank you very much. Obviously, people have been listening nicely, which is always good. So first question, what does Cora stand for? Remember, it is the center of rotation of angulation. It's not the center of rotation and angulation. I've just got myself two pens here just to remind ourselves, if we hate about a point, we will create an angulation.
So this is a rotation that's occurring about a point and that creates an angulation. It's not a rotation and an angulation. We've got a center of rotation of the angulation. So just remember that all angles are created by rotating two lines about one point. That is what the chorus stands for. Question two, if the core is selected as the point of correction and the osteotomy is performed away from the core error, wedge osteotomy rule has been followed, so remember.
So osteotomy rules one, two and three. There is no for which I'm pleased about. Someone didn't like any of the osteotomy rules or for people didn't. So we're have to go back over that. And the majority of the people have correctly identified that it's rule two. So rule one was that the corer and the so the point of correction and the osteotomy are located at the Cora rule three was that neither were located at the corner.
Rule two is the one we sometimes use where we've selected the chora to rotate about, but the osteotomy is performed away from it. So that was rule number two. And question three, we've just been through in the Q&A with respect to distraction osteogenesis. They'll rate is 1 millimeter a day and the rhythm that is divided into four. We do see it quite often divided into three, because isopods software allows us to divide one into 3 using our struts.
But the ideal rate for bone formation is 4 times a day. The ideal rate for a patient to get more than six hours uninterrupted rest is to go 3 times a day because that gives you 8 hours sleep as opposed to six hours sleep. So I do think there is a benefit to the iPod from that perspective. So just some cases I'll go through very quickly, a couple of cases.
So just to show you, I'm just looking at my other screen, which case is first? So this first case, I'll just show you, this is just a nice example of what I was talking about before. This is actually my radiographer. She's given permission to share this slides. She had a nasty open Taylor body fracture dislocation, a tibial plateau fracture and a horse riding accident.
It was fixed elsewhere, and she has a malunion of the proximal tibia. And we did our malalignment test. So here's a standing X-rays. We've got a malalignment test just refreshing our memories again, showing the shift of her weight bearing axis of the limb immediately compared to the normal side. So we always ask what is normal? That shows me that the medial proximal tibial angle was abnormal?
Remember that? And that is where we come and assess it on trauma card or other planning software, her or her corer is located in the knee itself. So really high. And I've chosen to do an osteotomy away, so I'm planning a rule two correction here just to show you and we can take out the hardware percutaneous. So this is done minimally invasively.
I use a fixator. And this is a special deformity fixator. It's not just an ex fix its place perpendicular to the axis of each segment of the bone. The choro was right up in the joint, so I'm going to go as high as I can. And this thing gives me a dome osteotomy, a curved osteotome based off the corner. I can distract using my fixator.
I can correct and then I can compress it and then I can percutaneous apply a slap muscular plate. And then we can come back and see that she's now aligned normally and heals, so that's just the technique of fixator assisted deformity correction. It's not an ex fix, it's a proper deformity correction fixator.
Going on, so this might be the sort of thing you could envisage in a Viva, and one of the things about the farke's exam is that there is huge overlaps in all of the tables in the Viva. What can appear in PEDs could also appear in basic science and could also appear in anatomy. What could appear in trauma could appear pretty much anywhere in the Viva.
And if you know your trauma. And if you know your anatomy. And if you know your basic science, I'm pretty confident you could pass the sharks Viva without much knowledge of actually any of the genuine pathologies, because almost all of the survivors rely on basic principles, which come from an understanding of basic science, anatomy and trauma, which can appear in huge amounts across the board.
So if you imagine you got this X right now, this could appear on the table. It could also appear on the our trauma table. You could have a vyver on the management of open injuries focusing primarily around the boat guidance. So you need to know inside out the first aid management of an open fracture doesn't matter if it's an adult or child.
You need to know your boast a nice energy. 37 guidelines for the management of open fractures and that's not the 2009 version, which was open tibia. That's now the updated 2017 version that includes all open fractures. You need to know about the antimicrobial prophylaxis, you need to know about the steps you need to know for anybody under the age of 16 that you have to mention non-accidental injury on the vyver table.
So this child may have been unsupervised, left with the front door open and has run out into the road and been hit by a car. So is there a social services circumstance, that sort of thing? This is a high energy injury because it's an open injury, so you have to have remember when we go back to what I call and I always tell my trainees these packaged answers. If I have a high energy trauma answer, there is always the well, so this is a high energy fracture, I would ensure the patient is managed as per its principles, the resuscitated as a whole.
Assuming there are no other issues or distracting injuries, I would manage the injury specifically. One of the things and the real techniques in vivas from my point is you take control. And that means you show the examiner that you've got confidence, not arrogance. Big difference. And you show the examiner you know what you're talking about by giving them enough information that they don't have to tease it from you, but also not wittering on so that you don't get to the valuable point scoring bits.
So here, if you're talking about managing the patient, assessing it, Yes. Don't sit there and go and assess them as ATMs and I check their airway, check their breathing, I'd feel that your care is central to their circulation. I get a couple of candidates because this is not an Atlas Viva. You can say I would assess and manage the patient as per its protocol and ensure they are adequately resuscitated.
And if the examiner wants in a fatal favor, you say, oh, right, what does the test protocol mean then? And he'll ask you, and that's where the Viva will go. So you've got to move it forward. You mustn't forget to say that stuff because if you don't say it, you can't get the marks for it. But you can say it in a way that intimates your thoroughly understanding of it and you know how to progress the VBA in a safe manner.
Similarly, all open injuries get the most for chat or periodic fractures get the. These are high energy injuries at risk of compartment syndrome, neurovascular assessment, blah blah blah. Anybody that goes to an operating theatre, you have a packaged answer, assuming the patient is adequately marked and starved and consented for surgery. I would place the anesthetized patient at appropriately on my board with an arm table, deploy the image intensifier, conduct the who out prep and rate, and ask if I can begin with you, Mr. Whatever your packaged answer is in 30 seconds that says I've got experience of this problem, I'm in control of it.
I'm going to take it forward with you, Mr examiners, so we can get to the high scoring bits. So here in an open fracture, you can imagine being asked about boastful, you can imagine needing to talk about how are you going to manage a patient, a child in a trauma situation? You might get the discussions around neurovascular assessment or compartment syndrome because it can occur in this.
You might get the discussion around management of this child with an external fixator. And then how are you going to put on an X fix? How or how are you going to definitive measures? Are you going to elastic nail it or what? You need to know those answers. The other thing that can happen in a trauma survivor or any survivor is you think you've finished your question and your case and then the examiner goes very good or whatever he says.
They don't normally say very good, but he goes, OK. End of that, Viva. Remember, you get three questions in your 15 minutes or whatever it is. And then they leave the same X-ray up and you're going, oh, what's going on here? Then something's about to happen. And he goes, so this child was treated with an external fixator, and one year later, he comes back to you because he's got some pain in his ankle.
And this is actually how things happen in my vyver. One of the tables I was asked to. Describe the surgical approach for drainage of a septic arthritis of a hip of a two-year-old. Perfectly reasonable basic science or anatomy question on that table. The congenital and then he said, how would your approach differ for congenital dislocation of the hip?
That was kind of the next few marks. And that was my first bit of the Viva table. And then he said, great. So now you've shown me how you can open up and reduce a hip? Yes now you're going to tell me you want to look at your open reductions and see how well they correlated with your ultrasounds beforehand. Can you tell me a statistical way of assessing that?
So it was the same topic it led on, and my next survival was how do you do 2 by 2 table analysis and stats? The same table, the same examiner, the same topic suddenly to survivors. So you need to be aware and prepared for that. And don't. Don't be afraid or alarmed. If that happens, it can do.
It's a new topic. It's a new area for you to discuss. So this kid, a year ago, high energy open fracture chats discuss them around that those four manage with an ex fix. Same child a year later, comes back with painful ankle. Now what are you going to do? Well, we're going to describe X rays, and when you describe X rays, you say what you can see.
This is an X-ray of a skeleton, the immature child of the distal tibia and foot and foot. I can't see a lateral radiograph. I can see that there's some sort of X or ptosis or bony protuberance in the proximal metathesis on the lateral side of the tibia. There is suspicion of some abnormality or asymmetry in the distal tibial thisis. I can't see any obvious fractures or other abnormalities, such as soft tissue swellings, tumors or similar.
I would like some more information and some further imaging. 30 seconds. I've said everything I can see, I've shown the examiner, I'm mature, I know what I'm talking about. I possibly picked up on something. He'll now tell me. And this, indeed in this case, is a partial physical arrest of the distal tibia.
And you might get another image that might show a CT scan or something with some arrest here, or you might get an MRI that shows a change in signal here. Or we might just say yes, exactly. There's a partial physical arrest there. How might that have happened? Well, it could have been from a pin. Placement doesn't look like the fix was near it. This was probably the pin track here.
It's probably from the injury itself. Hi energy trauma wouldn't be surprised if he'd smashed his face up a bit, and he's now got an angular deformity created because he's got unobstructed growth on the medial side of the tibia. But Fischler rest on the lateral side. The examiner, OK, is there anything you want to do? I take more history.
Exactly what are the symptoms? What are the problems? Has he noticed a deformity? Does he have any pain? I'd examine him for joint range of motion scarring because he's had a high energy, open fractures. You've got a leg full of skin grafts and I performed some more imaging. And here when we look, we can see just where we've gone back to our deformity assessment on this one.
The chora is located in the talus, not even in the tibia, and the angle from the Dome of the tolerance points to his other hip. It doesn't even point up the right leg, so he has a big deformity 11 or 12 degrees of acquired Vargas in the ankle from partial physio to rest. So the examiner may be really good. Let you go down the route of assessing that, or the examiner may present this to you and say yes, he's a partial progress.
It's got quite a big deformity. It's about 11 degrees. What do you think you want to do? And then you can have a mature and sensible discussion and you're into a really high end vyver now. OK, this is not your entry question of here's a partial physical arrest in the child who's yet not yet reached skeletal maturity. What are you going to do?
OK, so it's not your opening question, but you can take it and you can keep it really simple. You say, well. Firstly, I would like to quantify the deformity and the effect on the patient. I probably like to know the amount of growth remaining to see if there's going to be a significant increase in the deformity before he reaches skeletal maturity, or we think he's nearly a maximal deformity anyhow.
And then I'd like to assess the soft tissues, and then I'd like to counsel the patient as to the pros and cons of intervention. And at what time the examiners go very good. So, OK, he's not got a lot of growth remaining. We think he's probably only got about six months left. He's done most of his growth spurt. Mum's not buying any new shoes anymore. And what he'd like to know is, what can you do?
And then you can talk about principles of correction, gradual deformity correction, acute deformity correction and so on. And the Viva will go away. But by that point, you will be up at the 7 point mark. You'll be flying in a visor like that. So just to show you, this was a rule to correction again, another type of dome osteotomy, we've performed a sort of curve.
The curves are often not as big as you think they are. We've done a correction in theater using a hacksaw pod, so we've done an acute deformity correction, but with the benefit of external fixator. And the reason for that is he had a whole leg of skin grafting, so I didn't want to do any internal fixation on him. And he is now fully healed. So you can see now his joint is parallel to the axis of the tibia.
We've rotated, but he's got that bump we talked about from a rule to correction in kids. Obviously, they form a nice bridge of callus on this side and it'll smooth off. But he's got these bumps from rule to corrections or even in the fibula. Herro will three correction because of what we've had to do. Are I'll stop there.
Segment:0 .
Hello, everyone, and good evening, welcome to this joint session between our UK and orthopedic mentors group in preparation for the FRC exam. I'm honored today. I been joined by expert, lecturer Mr. Alex Trompeter for this principles of limb reconstruction and joint deformity correction.
Both groups are UK and orthopedic mentors group, or FRC as mentors group dedicated to teaching and educating you guys to pass the exam. We've produced many courses, books and seminars dedicated to the session to this target. Please join groups and follow us. There will be more lectures coming under both headings. This lecture itself is recorded and will be put on both websites, our website and the UK website, which you can look at a later time.
In the mentors group, we've got a telegram discussion platform where any questions related to this lecture or any other lecture will be discussed. If you want to join, it is record your interest and we will be adding you to arteriogram group for a later discussion this session. So we'll start with the introduction. Then there will be the lecture itself. If you have any questions about the lecture, just write them in the chat function.
We will keep a note of them and after the lecture, we will answer these questions after that. Mr trumpeter has got some case typical cases and how to answer them, which would be really worth your attention. Then the recording will stop and then we will have some private practice for you guys. If you are interested in the practice again, let us know by raising your hand and adding your name to the, you know, putting your interest in the chat, and we will keep a note of that.
We hope to finish at 930, but sometimes can overrun OK now. But lecturer today is an experienced surgeon. He's been doing limb reconstruction for seven years in London, in some St George's Hospital. Not only that, he is. It has passed the FRC exam, of course, but he has passed it with a.
Gold medal for scoring the highest mark, which is Walter Mason gold medal in 2011. He is as well the local. He is the program director for the Southwest London orthopedic program that makes them well equipped to know about teaching training and about what comes in the exam, so I would pay particular attention to today's lecture.
I'm really honored and without further ado, I've been talking too much. Here's Alex Trompeter. Thank you. I shall just light up my screen. That's the very kind introduction. Thank you to Luke and to the mentors group, to having me along today. It's an honor and a pleasure to be here.
I am going to give you an overview of the basic principles of deformity correction from the standpoint of what I think you would need to know and understand that in order to comfortably pass and Fox five a table, it is not the same as me saying I'm giving you an overview of all of deformity correction in an hour or a half an hour, and it's not the same as giving you a comprehensive course or skill set to go and perform these surgeries.
But it's about being able to understand and answer questions in a topic that can be a little bit daunting. And isn't something that everybody comes across during their training. These are my disclosures. None of them are relevant to this talk, but I have a breadth of involvement in education, so I thought I would break down what I think the ideal objectives for this should be.
And I've suggested that we look at understanding how to analyze a patient's deformity both clinically and geographically, then really look and understand the principles of correction and have a vague idea about how we might go away and go about correcting a deformity. And if there's time and I'm conscious of time, I do have some slides just on the basics of fine wire and hex upon fixation that might just be useful and a complement to the deformity component here.
So let's crack on and think, well, if we're going to assess and analyze a deformity, we've really got to understand the basic principles of actually how we go about that. We also need to understand what we would call normal, what is normal in the deformed limb and then a little bit of a system, if you like. And a methodology and approach for assessing a deformity, especially on an X-ray and then a means of planning a correction because this is absolutely one kind of surgery where planning is key and the planning usually is radiographic and needs to be recorded and documented in the records often saved into packs and so on, especially in this day and age.
With our medical legal culture ever changing, our record of our plan is going to be increasingly important. So what do we mean by a deformity? Well, truly, we're meaning the state of being misshapen and when it comes to the skeleton, what we're really talking about in the limbs. And for this, we're going to focus on the lower limb today, primarily in the femur and tibia.
We're talking about faulty alignment of the bone itself, which therefore has an effect on the limb axis or faulty in alignment and orientation of a joint. For a length issue, all of which are misshapen problems with the bone. And then those deformities can either be congenital or acquired simple or complex, usually meaning by complex. They often have a soft tissue component or maybe part of a syndrome or maybe multiple deformities within a limb.
They may have associated medical conditions. They may just be cosmetic and have no functional limitation at all. No impact on the patients daily life. Male union, which is probably a more common type of deformity that we will see in orthopedics, especially for those of us in a trauma practice and in an adult practice relates to faulty healing of the bone and failure of the bone to unite in such a way that the original normal axis of the bone and therefore the limb is not restored.
And of course, the impact of that may only be radiographic or there may be a clinical and functional component or the potential for a future problem. So a very small, aligned tibia that doesn't cause any symptoms or functional limitation now may lead to premature joint disease in the future. And so there's a consideration there to be had. Like all good things, when we come to assess the patient, we're going to need to consider the history, the examination.
And then the imaging and the history is pretty easy. From a deformity point of view, it's the usual suspects. Is there pain? Is there functional limitation? You've got to go in depth into that from an farke's point of view, if you're in a vyver situation, you may say I'd like to establish the patient's past surgical background, the history of trauma, their past medical history of Allen medications that may have an influence on surgery outcomes like anticoagulants, steroids.
And so forth. Many of those things, just as an aside, are all about having packaged answers in the farke's exam. If you've got here's an answer I give if I'm ever asked what operation I want to do, or here's an answer I give it a never asked how I assess a patient. You have this grouped packaged answer. So for histories, it's what's their past medical background.
Are they a smoker? Do they have any diabetes or other comorbidities that are influencing healing? Are they on any medications? I need to be aware of your show, an understanding of the importance of that in deformity, mainly from what we're talking about tonight, there's going to be a congenital problem, i.e. they've had the problem lifelong or it's an acquired problem, usually after trauma or similar.
And then what the functional impact is and what interventions they've had so far, if they've had a leg length discrepancy and they've not even tried a shoe raise yet, you may consider that before embarking on surgery. Examination really is relatively straightforward. If you get an examination in the clinical, there will be a huge amount to talk about primarily on observation first and foremost and using your descriptive terms.
We must look at the gait for the patient, usually in deformity, you may see things like various thrust in various limbs or a vagus. Obviously vagus gait in a more vagus knee and similar. You may see a short leg gait and therefore an issue with that they may be using walking aids or splints or shoe raises. You'll need to undress the patient to assess the scars and the soft tissue envelope, including in congenital and in acquired conditions.
So trauma there might be previous plastic surgery and so on. But in congenital, they may have some clear signs of the underlying pathology, and we'll come to that in some of the cases later. You'll need to assess them from the front, back and side. You'll need to do your tests for leg length discrepancy. Usually, the galaxy is my preferred test. And you must examine the joints for range of motion and for stability, and that's incredibly important, especially in acquiring congenital deformities.
And we mustn't forget the rotational profile and the neurological and vascular status of the limb. Rotational profile assessment is really key. There are some very good descriptions in the femur, we're going to look at the difference in rotation from one side to the other. The tibia is sometimes a bit harder. We can look at things like the foot progression angle. Actually, I do it with the patient prone and bending the knee up, but this is a similar net result.
This is pretty normal on the patient's left. On the patient's right. Here, you can see the foot is externally rotated to about 50, maybe even 60 degrees. And that clear external tibial torsion there. We're going to come on now to the real meat of the issue. What I've sort of thought probably everybody wants to get from tonight, and that is how are we going to assess and plan deformity correction?
One of the most important things in deformity correction is ensuring that we get proper imaging taken in order to do proper planning from it. You cannot plan osteotomy of the limb about the knee or four focal knee X-ray. You have to have long standing alignment images. You cannot plan off X-rays if the patient is male positioned and the X-rays aren't orthogonal. So there are some golden rules of deformity correction.
And the first two really are long. Leg imaging must be taken with the patella pointing forwards, as you can see here under my cursor, and not with the patella pointing sideways. Because that will be key for showing you partly rotational profile issues, but also the appearance of varus and valgus magnitudes change depending on the degree of rotation in the limb as you hold it in one way or the other.
So it's really important we understand that. And then similarly length issues can cause apparent variation Vargas of limbs if you don't stand the patient on blocks. So again, it's really important that you stand your patients on blocks and level the pelvis when it comes to imaging. If you don't believe me, here's a case I just found in my X-ray bank. From the other day, this lady came to me with a tibial torsion issue on the left of your screen.
You can see it's the right leg. We're looking at this. Here is the patella pointing forwards, and you can clearly see she's got a rotational profile abnormality because we now can't see an AP of the ankle. The foot appears to be pointing sideways when she points her feet forwards. She's got a patella that's now internally rotated. She has an apparent Vargas of the limb, and you get a really different picture of assessing her deformity.
So you've got to be aware of that. If you're lucky, the radiographers will take both sets for you or if you know what you're getting, you can ask for both sets and they will tell you how they positioned the feet. The next thing is then understanding the way and the methodology that we use to assess the limb from a deformity point of view.
And this comes back to understanding the axes of the bones and that's of the bones, not the limb at this point in time. And we'll come to the overall test in a minute. But broadly speaking, we can use the mechanical axis of a bone to measure things or the anatomic axis of a bone to measure things. But what we mustn't do at any point is interchange our choice.
Once you've set your sights on one, stick to PM until that case is finished, because if you muck them up or interchange accidentally halfway through, we'll have trouble. Anatomic referencing refers to what anatomic assessment and planning refers to use of the anatomic axis of a bone, which is defined primarily by the midpoint here of the width of the dialysis, as seen on an X-ray.
It is the width of the cortical bonus in an X-ray. It's not the width of the canal. It's not the width of the bone itself as a whole. On the tube, it's the width of the bone seen on an X-ray. And remember, not all bones are perfectly round and you take two points in the dialysis. And the midpoint of those two lines across the dialysis gives you an extension up and down what usually is the canal or canal light area, and that's the anatomic axis of the bone.
Your mechanical axis is taken from the center of the joint above to the center of the joint below. So they are wildly different. An angle formed with the joint at each end of those axes gives you your, for example, distal femoral angle here lateral distal femoral angle or your medial proximal tibial angle. And they are prefixed by either an A because you use the anatomic lateral distal femoral angle planning method or an m because you use the mechanical lateral distal femoral angle method.
And if you look here specifically for the femur, more than anything, the numbers are very different. The lateral distal femoral angle in anatomic and axis planning is 81 degrees. The mechanical lateral distal femoral angle is 88 degrees, so if you interchange them, you'll suddenly introduce a difference of 8 or 9 degrees in your assessment and you won't know where it's come from. Just as a pictorial representation mechanical axis, central joint above to below an atomic axis mid-point of the width of the apparent bone width on X-ray through two points of the dialysis center.
The tibia, the mechanical, inner and almost overlying. There's actually two to three Mils difference. The femur, as I say, very different indeed. Just just zooming in Allen again a little bit more and you can see in the tibia, they're not quite coincidental, but we can assume that almost one in the same. But the FEMA incredibly different. So once we know how we're going to or which method we want to use anatomic or mechanical, we can now start to go and assess the radiographs fully.
And there are some steps in which we should go about things, because not always is a deformity obvious. Not always is a deformity single, there might be more than one. And if there is an obvious deformity, I clinically it's not always obvious where it is geographically or it's not always where you expect it.
So we go through a series of steps of assessing things in order that we don't miss stuff primarily. And first, we do the alignment test. Then we do the male orientation test. Then we can look at each bone individually and then we can look at all the different planes for that bone. And then finally, we can come to defining where the deformity lives, which we'll talk about in a second.
So the alignment test. Is a test essentially of the weight bearing axis of the limb and in the lower limb, we're talking about the axis from the center of the ankle to the center of the hip, and we're familiar with this generally, if anyone's ever done a knee replacement or a knee job or any of those sort of things, you look at this quite a lot. And this malalignment test overall is a really good quick test of telling you, is there a deformity or not?
We normally see the weight bearing axis of the limb pass just medial to the midpoint of the tibiofemoral joint AM here. So that's a good overall screening test for is there any problem with an alignment in this limb as a whole? Sometimes the length issues don't really demonstrate a Big Mel alignment test. Sometimes complex double level deformities or deformities with translation as well may not show a malalignment test is positive, but it's a good place to start.
Next is the male orientation test, and we come back to that understanding, then of which axes we're using to assess the bone because we need to look and see where our joint angles are and whether therefore the joints are orientated correctly at the end of each bone relative to its axis. Hence, male orientation test. And that means we need to look at the proximal femur, distal femur, proximal tibia, distal tibia, and we'll look at the classic.
And for most folks there, will you be looking, for example, at the medial proximal tibial angle? 87 degrees? And we know that through the access to the joint. So there's a three degrees of inherent virus in the knee and the distal femoral angle, usually either 88 mechanically or 81 laterally and 81 will be familiar again to those of you done knee replacements with interim medullary femoral referencing.
And we'll come back to that in a second. And you just need to broadly that there's about 9 degrees of Vargas from the anatomic axis to the joint line. You can also look at the joint line convergence angle here, and that tells you you've got an intra articular deformity or not if the joint converges on one side or the other. So that's a male orientation test, and it's really important because if one of these angles is wrong, it normally tells you there's a deformity in that bone and towards which end of the bone it lifts.
So you're starting like a detective to unmask where the deformity might be hiding. And you therefore need to know these numbers, or at least have a chart with these numbers to understand what's normal so that when abnormal crops up, you can pick it out. Just say you understand why the media proximal tibial angle is at 87 degrees, OK, because when we single leg stance, which is what we do most of the time when we're walking or anything, we add ductile leg to underneath our midline.
So our weight bearing axis of this limb shifts to be under the central axis of the human form, which means that our joint, which was inherently various, slides around to being neutral and parallel to the ground. And that means you lose that three degrees of varus of the joint single leg stance. And that's why if you've ever wondered why your knee components are also rotated by 3 degrees as well, there comes to accommodate that three degrees of varus in the tibia at the medial proximal tibial angle.
So that's why there's that mystery three degrees of rotation in the knee replacement component placement. And it comes from this. So that when you flex your knee, you go back to 90 degrees in a flexed position in your replaced knee. So we now understand that we might have a mal alignment, we now understand that we may not have a male orientated joint.
We've got to then start to look at the deformity in a little bit more detail. Now, of course, life isn't straightforward and deformities don't ever appear in Just the frontal or sagittal plane. Actually, deformities usually in the oblique plane or deformities, unless they're double level or sort of complex with rotational. But a single plane deformity always sits in one oblique plane now that might be in the coronal plane, but usually there's some way around the clock face where you'll see the deformity only in one plane, and that's oblique.
But of course, we don't get our x-rays taken in that plane. We get our x-rays taken in the two cranial and sagittal planes. Deformities may also annoyingly be located in the joint, or they may even we will come to this. This is where the head scratcher begins not be located inside the bone at all. From a mathematical standpoint, and that is a really crazy thing to understand and is a really important thing to understand when you come to correcting a deformity.
Now, if we look at these X rays, we can start at the top left, these are not x-rays or these schematics. And if we look at this first picture on the top left, we've got a malalignment test here. This dotted line, if you imagine you're looking at X-rays here, but has told me that we've got an issue here with weight bearing being shifted over to the medial side. So I'm thinking, oh, there must be a deformity here.
And then in this example, we look on the medial proximal tibial angle is less than 80 85 degrees. That tells me the deformity is probably located in the medial proximal in the proximal tibia here because the male orientation test has identified an abnormality with this angle. Similarly, same alignment test here, but we've now got an abnormality because our lateral distal femoral angle is increased.
So we've got distal femoral virus leading to the same net result as medial proximal tibial virus. And you could indeed have a combined leading to an even greater deformity. Similar in the distal tibia here, here's a malalignment test now when the joint deformity is over in the proximal femur or the distal tibia, the effect on muscle alignment is less.
Then if the joints around the knee, because your weight, your center of your joint doesn't translate very much compared to with a knee joint deformity, and here you've done a male orientation test the distal tibial angles not right. So the deformity is located in the tibia, probably towards the bottom end. Again, here, similarly in the FEMA malalignment test is pretty, pretty reasonable.
But the male orientation test has shown a big various male male problem in the proximal femur. And then similarly, we can have issues with articular deformity here. So this is really showing you right up in the joint here with a joint convergence problem and then this pattern deformities here. So we've kind of established where we think the deformity might live geographically.
We've taken a history, we take an examination. We've got beautiful standing, long legged views. We think we've identified there is a deformity. We think we know where the bone is that's involved in it. Now we've really got to work on describing the deformity in a mathematical way so that we can treat it with accuracy and provide the patient an outcome that is an appropriate mechanical solution for their mechanical problem.
You can't just sort of look at the bone and go. It looks a bit jaunty. I'm going to hit it with a hammer till it goes wobbly and then nail it straight. It does work occasionally, but it's not very good from a documentation point of view. And if you get more complex deformities, that's a bit of a problem. So that approach only works to so far.
So the corer, the center of rotation of angulation, OK, not the center of rotation and angulation, the center of rotation of angulation and the language is important because this tells you the point about which the deformity is located, such that if you rotated the axes of the bone at each end around that point, the deformity would disappear, i.e. it's the point of angulation about which things have rotated.
Now let's just break that down a little bit further. Whenever we assess a deformity, we need to pick an axis of the segment of bone. Either side of where we think the deformity is living now for ease and so on. Here is a deformity living in the middle of the tibia. OK we can take a predictable axis up and down the tibia because we know from what's normal, what we saw at the beginning, what these magical joint line angles are.
But when you plot the joint against the Axis of the bone, it is a predictable number. So we know that the lateral distal tibial angle. So a line between the axis of the distal tibia and the tonic and the joint surface of the distal tibia forms 89 degrees. And I know that the medial proximal tibial angle align across the joint and a line down the axis of the proximal segment form 87 degrees. Therefore, we can extrapolate these lines down on the axis of each segment of the bone and where they cross is the chora.
OK go through that again, because this is key. Joint line at the top and atomic axis at the top angle between the both normal 87 degrees. Same at the bottom and atomic axis joint line normal 89 degrees. Take those lines up through each segment of the bone till they meet and that there is your chora. And if you look at this with your mind's eye, if you imagine cutting the bone here, sticking a drawing pin in the page and rotating around this point.
And we did this with our bent bone. Everything would line up. What's important to realize is that sometimes where you think the deformity lives, like here in a big blob of callus is not where the deformity lives because mathematically axis of the bone relative to the joint axis of the bone relative to the joint, the core is here, and that's where you would need to rotate your angulation.
In order to get rid of the deformity, if you stuck your drawing pin about here where you think, oh, here's the blob of callus, you wouldn't correct your deformity, you would induce a translation as well. I'll show you that in a minute. So here, just so we go a little bit further malalignment test, right?
Bones not normal. Male orientation test, ok? Distal femur, pretty normal, proximal tibia. Very abnormal. We'll use our joint line, and it usually for purists sake, you might choose to use actually the opposite side of the joint and extend it as opposed to using the proximal tibia. But the same net effect anatomic axis of proximal segment, anatomic axis of distal segment.
And that gives us a chora with a magnitude of 30 degrees, i.e. a deformity of 30 degrees virus, in this case in the distal tibia. Do the same in the digital FEMA or the proximal tibia all around, so mammal alignment test mechanical axis deviation shown. Normal hair in the distal femur, laterally abnormal in the medial proximal tibia. To measure it and look, Lo and behold, the deformity is right up in the proximal tibia, almost in the joint.
And that has a special implication when it comes to correction. So when we look at that again, just say, you know, the deformity can be obvious. It may not be obvious. As we said, it may not be at the same level as a previous fracture. It may live outside the bone or even in a joint. And here are just some examples of where you can get caught out.
This is really important shows the importance of two views. These are all my own cases. Here's a femur left femur malunion sent to me because of medial knee pain, and they were a bit early for a knee replacement. And you look at this and you take a really close look and you can measure the core here. And you can work it all out and then you take a lateral X-ray and they have another deformity, but disappointingly isn't located at the same level on the AP and a lateral.
And this deformity isn't really located where you think it is. This deformity is located about somewhere up here on the lateral. If you think extending your axes of each bone, this deformity on the lateral lives pretty much in the hip. This deformity lives in the middle of the femur. To correct both at once, you need to think, how are you going to overcome that? He has a proximal tibia, male union, and you can see here, this very clearly is going to be living around here and we can do our orientations, and that tells us that the core is indeed pretty much bang smack in the middle of that zone of fracture, which wouldn't be surprising because it's not really healed with much in the way of translation.
It's just healed with angulation. And then here we've got a medial proximal tibia fixation, malalignment test, so this is central joint above to below. These are all done on trauma card tells me that the weight bearing axis has shifted right over medially. Here we can go for our male orientation test, and here we can see that the axis of the distal tibia and then an axis coming down from the proximal tibia.
Tell me that my joint, my deformity is located here at 7 degrees in the joint itself. So the core here is located right in the joint, which then means you've got to think, how can you correct this if you can't stick your drawing pin in the joint to correct your bent bone? And then we've got a planning for correction, where we can show we can get the limb straight. And this is a great way of recording your documentation of how you've correct thumb your correction before you've even done it, from a notes and records point of view, and I'll talk through this in a minute.
OK, so that's part one, how we assess deformity. I better crack on because I'm conscious of time. I'm going to go through how we correct deformity, and then I will probably see how, if the time, if I do anything on the frames. So there's a bit of a language issue here. This bit. Don't get too worried about, but broadly speaking, a corer is actually not a point in space.
It's a cylinder because a hinge can be infinitely long about which if you rotate, you could still get the same result. But broadly speaking? You can put a any, anywhere you like. The core for the deformity is defined, as we said, mathematically here. If you imagine there was a 3D dowel going across the screen, not towards the screen, you could choose to pick anywhere along that if there was a 3D dowel going through the screen here.
All of this would be one corer infinitely in any distance, because if I rotated about my 3D rod in this plane, my deformity would correct. In this one, it's different. The apex of correction of angulation is broadly, in many ways, the location of where you choose to pin your correction about. So where you choose to make your hinge to correct your deformity.
The chora is defined you can't change the core of the core is defined mathematically. You can choose your point of rotation for your correction. That's not the same as the chorus, so you can choose a point of rotation for your correction, but you cannot change the anatomic location of the chora from maths. You can choose where to put your osteotomy. And your point of correction.
Hinge, the point you choose can be or cannot be at the corner and you osteotomy can be and cannot be at the corner. And those two things that you have choice over where you put your hinge and where you put your osteotomy lead to different results, depending on what you do. And these are called the osteotomy rules. Osteotomy, rule one.
Essentially says you choose to perform your correction where the camera is located. And you choose to perform your osteotomy through the chora. This is the ideal for making a bone straight. If you look at this picture and ignore the three dots, just look at the. This is the core of this axis and this axis in this segment of bone. If we choose to cut the bone across here.
Ignore the little wedges for the moment, which is to divide the bone and rotate about this central point or two axes will line up. And our deformity is corrected by virtue of choosing a point of correction at the corner. And an osteotomy through the chora. OK, that is a rule one, you can do it via closing wedge and you can do it via an opening wedge. But broadly speaking, you've chosen to put your osteotomy at the corner And your hinge at the corner.
Everything goes straight afterwards. You could choose if you wanted. Too, is the deformity same picture? Bent leg two axes, just look at the middle dot. We've chosen to still put our hinge here or chosen point of rotation, but we've cut the bone away from where the deformity is located. And we're now going to rotate the cut piece of bone around the hinge, so imagine this bone is still long enough that it lives up here.
There's a virtual piece of bone and this piece is rotating around this point. What on Earth would we do that? Well, this is what you need to do when you're deformity is located in a joint, because clearly, if your proximal tibia is here, I can't cut you through your proximal tibia and swing it. We have to cut you in the tibial metathesis and divide the bone there.
But we can still rotate about the actual location of the deformity. The net result is you get a bump. And depending on the magnitude of your correction and the distance between the point of rotation and your osteotomy, the magnitude of the bump would be decided and sometimes it's not a problem. So we quite often see this, for example, in a fibular osteotomy when we're busy correcting the tibia because the fibula is not at the point of rotation.
So you'll often see a bump or a problem with the fibula afterwards. They often heal or it will smooth off. Or sometimes you might need to go and shave off the bump. You also need to ensure you have enough contact on this side for healing. So that's rule two. You're going to rotate at the corner, but you're going to cut the bone away from the corner.
No prizes for guessing rule three. Here is your deformity. Here is your chorus. Still, this time we're going to choose to rotate away from our chora, so we're going to pick another point in space to make our hinge. Am I going to divide away from our Cobra and look what happens? We induce a translation.
So our axes do not line up afterwards. This is usually unintentional. This is usually not desirable. There are very few occasions where you can use this as a clever way of treating two deformities in one bone. Don't worry about that for now. All you need to know is this rule one. You're correct at the corner.
You divide the bone at the core rule to you. Correct it the corer. You divide the bone away from the corner and rule three. You do not involve the core in either of your choices. It's really that simple. Just one last schematic, so you can see in rule one, the axes stay the same. In rule two, the axis stays the same, and in rule three, the axis translates.
Dame osteotomy, some of you may have come across this hour rule tos, you're going to take your corner, you're going to rotate about your corner, that you're going to divide the bone away from the corner and give yourself just more bone contact. It's just a way of giving you more bone contact and reducing the presence of a bump. That's all, but it's still a rule to correction.
And a note on osteotomy says this is a surgical division of the bone. The aim is to try and recreate and promote fracture healing. Meeting you lots of different ways you can do compression osteotomy, you can do opening wedge, closing wedge, you can do distraction osteotomy, all of them need to preserve biology in one way or the other, in an ideal, especially.
So if you're going to be growing new bone in the gap. Um, I've written a paper this is actually a shameless plug, but we wrote quite a nice review of all of the different ways of dividing a bone. And it's a fairly easy read. I think it's free to download. If not, I can share it with you guys afterwards. But this I hope the guys up in Liverpool and just goes through the different methods of dividing a bone and the pros and cons.
My preference is a drill, an austere team. So here you go. Some drill holes and then we use an austere tone to join the dots, and that gives us a pretty neat osteotomy. Here's a dome osteotomy to be created. So we can use a half pin at the corner and rotate a Rancho cube around. And that gives us a series of curve drilled holes that then gives us a curved osteotome for a dome.
When we come to correcting, we need to choose whether we're going to correct acutely by one or gradually, and that will depend on several things. The soft tissues dictate it. So the classic is a vigorous tibia with a lot of scarring on the medial side of the tibia going to Vegas. You can't acutely correct because the soft tissues won't allow it.
You'd have to do a flap or something at the same time. The other one, a classic, is internal rotation to external rotation of the external to internal rotation of the tibia. So big rotations of the tibia and pulling on the perineal nerve acutely. The patient may not like it. They may get certain pain the size of the deformity. Acute rotations of the tibia over about 30 degrees 20 30 degrees are quite hard to do acutely.
You might have associated lengthening, and therefore you'll need to be guided by you're lengthening rate. You might not have the skills to do acute corrections accurately. You might only be able to do them gradually. Gradual correction, obviously, usually with a frame. And then implant choice, you can do internal works well for acute correction external usually works well for gradual.
You can do acute correction with external, so do it on the table. But you might be worried about the soft tissues or there may be lower infection risks and similar just by using a frame. And then we can use the benefits of external fixator and their accuracy to do a correction, but then replace them there and then or you maintain the reduction with your fixator and then employ internal fixation on the table there.
And then and then take away the fixator at the end. Then they get the best of both worlds. They get a fixator assisted deformity correction. You can use a hacksaw pod that's called chaos surgery, computerized hack support, assisted orthopedic surgery where you do the deformity correction using a fixator. Slide your plate or your nail in. Take the fixator off.
Hey, presto, accuracy and internal fixation all in one go. If we're going to go and do this with a Elisa of frame and we're talking about frames here because I don't need to spend time telling you about how to use a plate. We just need to understand a little bit about how the tools work and how we can use them for what we've been talking about. I'm from a mechanics point of view, just to remind you, plates and multilateral fixtures work on the off axis fixation and/or on the cantilever loading.
So that's just sort of diving boards. Your suspended your cantilever roofs, so they're fixed at one side and cantilevered at the other. They lead to an isotropic loading of the bone in the implant, which causes potential problems with healing and lysis and so on. Implants that are located about the axis of the bone are what we call on axis or beam loaded, so that means they're supported at both sides and nail is being loaded.
It's just very short beam. The frame is clearly being loaded if you're using wires, not half pins, and that gives you a much more even isotropic loaded device. And those of you coming up to the Fox should know those terms. Isotropic anisotropy inside out. In the frame, the beams of the wires, not the rings, so the beams of the wires, not the rings.
And the wires are under tension, just like your. These things, what you need to understand is that something can be inherently very weak, very floppy when it's not loaded under tension. A wicker chair, for example, the wicker chair is made of grass. Grass is not very strong stuff. I can slap the blades of grass in my lawn quite happily. Tennis rackets are strung with cat gut. Historically, that is floppy stuff.
Trampolines, anyone who's put one together, we'll know when they take the mat, out of the box. The mat is floppy and hopeless. I've never built a suspension bridge, but I imagine the cables are quite floppy before you string them up. The unique thing for all of these here is all of those things are put under detention. Your cat gut is strung tightly in your channel racket.
Your trampoline has about 150 Springs around the outside. Your cables on a suspension bridge are pulled taut. Your chair of wicker here is pulled taut, and as soon as those things are pulled taut, they support load. Just like your clothesline, you string your clothesline loosely between two poles in the garden and your clothes will hit the floor, but you pull them tight. And that clothesline, the same clothesline went under tension will support several pairs of wet jeans much, much heavier.
So as an object under tension will resist resist load and decimation. And that is the principle of how the fine wires work. So they are very, very good in terms of supporting the limb with a very small biologic footprint. We also, though, need to understand how we can apply them to a bone for deformity correction purposes. There are several components just to refresh you.
You have wires. Olives are not the olives here. They just add some stability there. Bayonet tipped we have rings usually complete or two half rings join to make a complete ring. We have elements to join the wires to the ring. And those of you that do frames will know you should always build to the wire and not pull the wire to you. So the wire crosses the middle of the hole.
It goes through the middle of the fixation. If it goes to the edge of the hole, it goes to the edge of the fixation. If the wire stands off, we use washers or even drops. Half pins are clearly cantilever structures. There are all sorts of types. Generally now more modern day ones will be coated for deformity frames and just plain for temporizing external fixator.
They may have self-cleaning tips. They may be smooth tip. They may be conical. You need to these sort of things for describing implants, and they have to be able to be captured to the ring one way or another. You need rods to be able to join your rings together. And you can use certain devices to make the rings get further apart or closer, that might be for a lengthy, and we can also use hinges in the frame to allow us to take a bent frame and slowly straighten it, which we might want to do with a deformity correction.
We need a lot of nuts to put it all together. Generally, two rings per segment of bone, two wires per ring near far fixation gives you a stable construct. That's a very simplistic view of a laser oral fixation, but it's a reasonable start for those of you that don't know it and you maybe get past one in the exam, you could say that much and you'll be fine. In order to do a correction, we're going to use that same method of analyzing by applying our frames, so we talked about referencing or the alignment of the axis of the bone relative to the joint at one end and the alignment of the axis of the bone relative to the joints at the other.
Well, if you put your frame on a bone with it aligned to the joint at one end and the line to the joint or the other. If you've got a broken bone and you do that, the bone will straighten at the end of it. And if you've got a bent bone, then you'll be able to bend, frame together and then break it and straighten your frame. You'll have a straight bond.
So if you have your frame reference to the joint above and joint below, you will have a straight bond at the end of things. this is what I mean. This wire here we go referenced to the joint above. This was a reference to the joint below. And then Lo and behold, you put a frame on it like this is an acute fracture, but the leg is straight, not difficult. It's aqueous or K wires and a bit of maths. So anybody that thinks that a Lazaroff surgery has some mystique, it's actually OK.
We can reference and just remember if we're going to do that anatomically or mechanically. So here's our wire. Just remember we're doing that. We've got to understand which reference we're referring to in the femur. If we're going to do our planning with this, we need to understand, as I say, coming back to where our core lives and where we're going to correct through, so let's say we remind ourselves of our osteotomy rules.
Type one so we've got a osteotomy here. We're going to end up with a osteotomy and the hinge at the level of the deformity. Here's an example. Here's our deformity. Here's our hinge. Pretty much on the line of our deformity. We can divide the bone with reference to our frame. Approximately here I'll frame distally here to the joint.
We divide the bone, we straighten the frame and the bone straightens. OK, that is the principles of using an laser frame for deformity correction you can manage. Increasingly, complex deformities within inches are of frame double levels. Here you go. Lots of different bets. You can even rotate by offsetting the rods relative to each other.
The problem with it is the more complex, the deformity, the more complex frame, and at some point, the frame becomes a manageable for both surgeon and patient. Say, wouldn't it be nice if you didn't have to really think about any of that? And you could address all of those things in one go. And that's what a pod does. It's still in Israel frame. It still tackles the issue of fixation to the bone and the biologic aspects and so on.
But it's taken some of that thinking and planning away from us. I think the analogy is a bit like a computer assisted joint replacement. You probably still need to know how to balance a knee replacement properly. And if you're going to use a pod, you probably still no need to know how to do proper deformity correction, but it just means you can tackle a more complex deformity in one go.
It is based on what's called the Stuart golf platform, which is a octahedral area in space divided by 6 adjustable lengths, so six struts to platforms. These are typically seen underneath flight simulators, and if you move any one of these, the whole geometry of all of the triangles created between each set of struts changes. Which is used by Nasa for docking the space shuttle into the International Space station, so we think about how you move to things in space relative to each other.
They have a virtual isopod between them telling them how to change the length of each relative vector to allow the space shuttle to dock. It's super clever. If you're a space geek like me, you'll love this stuff. So a pod is just that the two rings with a laser of stuff at each end, joining to the bone. And this six piston movable beast in the middle that can allow for the movement of the bone in any direction in each segment relative to the other.
So it is the movement of two wings relative to each other in space. Each segment of bone moves with a ring, so you'd have two rings here. A segment above a segment below the six struts usually have a predictable attachment to the rings. And it allows movement in all directions. So you can have axilo translation here, the struts will get longer.
You can have horizontal translation where we see the struts move in certain directions for some struts, so this strut, for example, will get shorter. This strut will get longer as you move things away. You might be able to correct an angular deformity and you can correct rotational problems. And of course, you can combine all of those into one prescription so that all deformities are addressed in one go by the computer.
That's the benefit. For a frame, you need struts, usually six of them, they have to go in the right place and there's non-negotiable. And you can put them the frame on to match a deformity so you can plan in advance and build a frame that matches your deformity so that when it's correct, the frame is neutral. That's quite a nice and elegant technique.
You can acutely correct a frame so you can undo the wreckage struts in the middle. Same on the TSF, same on the tail hex. And for example, in fracture surgery, you reduce your deformity and you can gradually do it. And it's basically an Elisa a-frame with specialist instrumentation in an octahedral six axis support, as I said, with a virtual hinge in it. That's the difference between a pod and an illiberal frame.
Nothing else. It needs a bit of software and in principle, just a couple more minutes before we get into our cases. But in principle for the software, you need to be able to describe the deformity. I tell the computer, what is the deformity you need to describe to the computer, the shape of your frame and the size of your frame, and you describe to the computer how that frame is related to the bone.
You also tell the computer what you'd like at the end. Usually a straight bone, please. And over what time frame? That's all. So define the deformity. You find the frame shape and the relationship between the two. Defining a deformity, we use the software on the computer, right long bone here. Here's a deformity.
This is an acute fracture at about four weeks down the line. They've had the flap now, the joints being fixed. We've got a shaft that's been a bit shortened, so we're going to measure it with the frame on now. There's some translation immediately by a centimeter. There's some translation posted by $0.2. Whatever the numbers, there's a bit of shortening. So we can put this in to the computer telling us that there's a deformity.
Usually they give you a dowel representation of the deformity. So a picture showing you and you can look at that and your x-ray, is that the same? OK, good. I've got my deformity measured, right? So you don't sort of make a mistake. Then you're going to tell the computer what the frame is like.
So in this one, we said, oh, we got 160 rings at each end. We've used a load of long struts. These are the settings on the strut. So the computer now knows the shape of your frame because the six stripes always go in the same place and then you've got to measure the frame and how it's related to the bone. So that's usually where the middle of the frame is relative to the middle of the bone, so it's a bit posterior to offset.
And so on. And then you get a picture of your deformity with the frame on it. And remember, in our picture, going back the bottom ring of the frame is pretty much at the level of the joint. So the bottom ring of the frame here is at the level of where our two dials are meeting because the bottom of the joint is here.
For those of you that are really interested, tell hacks and measure things differently, I'll skip past that. You don't need to know that. And then at the end, you just find your time scale and that's based around the rhythm and rate of correction and any latency period. And then the patient usually gets a prescription that tells them how to adjust each struck each day, such that the correction is undertaken.
And then you finish with a leg now of the look that the tibia is the tolerance is under the tibia in both planes because we've used the computer and it's told us how to address these struts to gradually move the bone back into place. And that is the use of a frame in deformity correction. I suppose there that I think is enough forever. It's not for me for a lifetime, but I'm sure that's probably still some brains up and maybe has generated a question or two.
Thank you very much. That was really, really interesting, and I enjoyed every bit of that. Congratulations on this really interesting talk. Fine so far we haven't got questions. I think everyone was just focusing on concentrating on what you are saying just to give the guys time to add questions. I will use this time to remind people of a couple of important things.
First of all, for your questions, please, please write them for everyone, address everyone in the chat function. If you have any questions, please write them down and we will answer them. The second thing is, we really appreciate your feedback, guys. All our UK will be sending you a feedback form. We really appreciate if you feel that it'll teach us how to improve and it'll, you know, it is your way of saying thank you to all the efforts that has been put into this lecture.
Please keep looking at the UK website and arteriogram group. We will tell you of the upcoming lectures. We've got one next week and are coming to the exam. We've got the five hour session today. It will be a short one because of the time. But if you are interested, please let us know. We've got a frequent online webinars Viva exam sessions. I think the next one is coming in October, around the tenth of October.
There is another one coming after that, so let us know. And these, I'm afraid, because the spaces are limited, they will finish very, very quickly as in the spaces will fill very quickly. So please let us know as soon as the other thing is a couple of, you know, really nice books for the exam. The UK have produced two books one Viva and one multiple choice question. I believe they are very, very important.
I used both of them actually for the exam and we've got our own mentors group concise notes for Orthopedics. Again, I would recommend it to everyone. It is very, very concise, and everyone who has used it found it useful. OK, the first question is. Uh, especially in the lengthening, in respect to mechanical access.
Wouldn't that create a new deformity? So I think, yeah, I had a look, this is a sort of two part question, so explain the lengthening of the female with respect to the mechanical and anatomic axis. And is there any issues with either? Obviously, the FEMA has two axes. And if we go back to the understanding, if you get longer, you need to be getting longer and access.
So if your implant for lengthening is based off a mechanical axis, when you get longer, you may induce a vagus deformity in the femur because you're going to be shifting downwards, not along the anatomic axis of the femur. So generally, if you're going for femoral lengthening, anatomic access is preferable generally nowadays for me. Anything femoral or lengthening? Indeed, most lengthening I do with an interim medullary lengthening male, which means that you remove the issue very much so of inducing unwanted deformity, especially over longer distances, because you're staying on an interim medullary device.
OK, thank you. So another question about what the concept of 3 point fixation in applying the bends. I'm not sure I really understand the question the 3 point fixation for the pins. I think what we're really meaning in terms of fixation with the frame is that any fixator, any frame device would ought to have at least two rings per boned segment and two fixation points per ring.
A wire is fixed at both sides of the ring and then goes through the bone with probably you'd think almost like a 1 broad point of fixation a half pin. We would try and use halves pins to be with as big a crossing angle as possible. 3 point fixation doesn't really apply with pins in the same way in pins. We're really talking about crossing angles to give us stability more than anything.
OK, so another question about if you can explain again, the Mayan alignment test and importance of joint orientation angles, please. So it's really important because obviously not all deformities are located in the dfacs or metaphysics of bones and the alignment test and the male orientation test help us just know if there's a deformity and roughly where it's located, but we then need to go a bit further and a bit deeper.
The joint lines relative to the axes can show us if there's a deformity towards the joint, but there may even be a deformity in the joint, and that may come just from a mathematic location. Like I showed you where it's because there's a translation or it may come from intra articular pathology. So in a very Vargas knee or in a hypoplastic lateral epicondyle or knee arthritis, those all cause deformities in or very close to the joint from pathology there.
So it's really important that we look carefully for where the deformity is located. So that we understand how we're going to overcome it and correct it. And sometimes it might be need to use an arthroplasty, or sometimes we choose an osteotomy like an FTO for a classic knee. Fto is really treating intra articular osteotomy with a or intra articular deformity.
Rather, with a rule to correction, you are taking an osteotomy and the metathesis to treat an intra articular deformity and pathology by shifting their weight. So it's really important we understand how to assess and analyze where the deformity lives so that we know where to offer treatment for it and how to treat it. Very good, thank you.
So a question about what is the biomechanical principles behind this deduction osteogenesis? So that's a whole other lecture. It's a distraction, osteogenesis is the formation of new bone under tension. It depends. It relies on tensile forces leading to bone formation. We know that bone responds to the mechanical environment around it.
We're used to thinking of it in compression, in fracture healing. But actually, most of the original work looking at fracture healing and bone healing and non-union management looked at tension. If you look at Lazaro's work, the original, the order of treatment was the nonunion was for distraction of the nonunion, and it increased tension, which increased stability.
Distraction osteogenesis is the creation of new bone in a surgical bone division. And by applying the correct rate and rhythm of that distraction, you will create new bone in the gap. I think it's a really big topic and probably one for another day or another talk. OK, so just a small question regarding that when you will remove the frame after achieving the required length lengthening.
Mm-hmm So when do you do that? Yeah, that's a really difficult one. So obviously you need to balance taking the frame off early enough so that the patient doesn't dislike you anymore versus keeping it on long enough that the bone is solid. And the typical time frame for a creation of new bone and distraction osteogenesis is generally one to two weeks of latency.
So that's before you move. Yeah, then the period of lengthening, which is usually at 1 millimeter a day and then a period of consolidation, which is usually at least twice as long as that, all again. So it depends on the size of the gap to how long the frame is. There are techniques now, which we can use, like plates off the lengthening or nails off the lengthening where we can do a lengthening and then change out internal fixation before the regenerate is consolidated.
Or we use an interim medullary device so that they don't have the issue of a frame at all. OK, thank you. What do you mean by the rest in frame correction? What do I mean by the rhythm? So the rate is the amount you move the bone in a whole day and the rhythm is the amount you do divide that whole day into. So anybody who's done an hour of frame will know that there are some lovely square nuts with dice numbers all the way around.
One two three four. And a full rotation of a nut is millimeter of travel on a rod. And the reason you have one two three 4 is you can divide that one into four equal increments six hours apart. That's a full day of correction because that allows you for optimum bone formation in the gap. And that's probably down to the cell cycle. If you go all the way back to your pre-clinical sciences at medical school and you'll remember there's a division phase and a resting phase in the cell cycle.
The cell cycles by virtue of giving them a rest and then distracting and giving them a rest and then distracting, you're probably influencing or matching the cell cycle in that process. So that's the rhythm. OK, so I think there's a last question, so is there is any difference in the principles of deformity correction for congenital deformities, degenerative or post-traumatic?
No, is the short answer and not in the principles of correction, the principles of assessing and managing the patient are sometimes a little different. Congenital deformities often have associated problems with joint laxity or other structures not being normal, not just the bone degenerative deformities. You need the difficult question around usually whether the patient has the ability to undergo deformity correction, whether it's in their interest, or would they be better served with joint replacement and then post traumatic.
Usually, as I say, is much of what we've talked about today. OK, so the last question, so now so what is the reverse dynamic technique in the frame? So there's reverse dynamic, so there's the idea of, well, there's two parts to reverse dynamite. So there's the tension and compression components of whether you apply tension or compression. But also then there's some really interesting work from Kenwright many years ago about the idea of being loading early and weight bearing early and then ultimately coming off something later as the fracture gap gets narrower and reducing load to reduce the strain in the gap and for healing.
It's a really complex thing dynamite as a whole. I tend to not do a lot of I dynamos my frames at the very end to see whether I think as a test to see whether the bone is United. I generally prefer to build stiffer, rigid constructs that I have more control over than the looser, dynamic constructs because I think that there's a little bit of more control from my side. But it's again another big topic.
OK, thank you very much. Obviously, people have been listening nicely, which is always good. So first question, what does Cora stand for? Remember, it is the center of rotation of angulation. It's not the center of rotation and angulation. I've just got myself two pens here just to remind ourselves, if we hate about a point, we will create an angulation.
So this is a rotation that's occurring about a point and that creates an angulation. It's not a rotation and an angulation. We've got a center of rotation of the angulation. So just remember that all angles are created by rotating two lines about one point. That is what the chorus stands for. Question two, if the core is selected as the point of correction and the osteotomy is performed away from the core error, wedge osteotomy rule has been followed, so remember.
So osteotomy rules one, two and three. There is no for which I'm pleased about. Someone didn't like any of the osteotomy rules or for people didn't. So we're have to go back over that. And the majority of the people have correctly identified that it's rule two. So rule one was that the corer and the so the point of correction and the osteotomy are located at the Cora rule three was that neither were located at the corner.
Rule two is the one we sometimes use where we've selected the chora to rotate about, but the osteotomy is performed away from it. So that was rule number two. And question three, we've just been through in the Q&A with respect to distraction osteogenesis. They'll rate is 1 millimeter a day and the rhythm that is divided into four. We do see it quite often divided into three, because isopods software allows us to divide one into 3 using our struts.
But the ideal rate for bone formation is 4 times a day. The ideal rate for a patient to get more than six hours uninterrupted rest is to go 3 times a day because that gives you 8 hours sleep as opposed to six hours sleep. So I do think there is a benefit to the iPod from that perspective. So just some cases I'll go through very quickly, a couple of cases.
So just to show you, I'm just looking at my other screen, which case is first? So this first case, I'll just show you, this is just a nice example of what I was talking about before. This is actually my radiographer. She's given permission to share this slides. She had a nasty open Taylor body fracture dislocation, a tibial plateau fracture and a horse riding accident.
It was fixed elsewhere, and she has a malunion of the proximal tibia. And we did our malalignment test. So here's a standing X-rays. We've got a malalignment test just refreshing our memories again, showing the shift of her weight bearing axis of the limb immediately compared to the normal side. So we always ask what is normal? That shows me that the medial proximal tibial angle was abnormal?
Remember that? And that is where we come and assess it on trauma card or other planning software, her or her corer is located in the knee itself. So really high. And I've chosen to do an osteotomy away, so I'm planning a rule two correction here just to show you and we can take out the hardware percutaneous. So this is done minimally invasively.
I use a fixator. And this is a special deformity fixator. It's not just an ex fix its place perpendicular to the axis of each segment of the bone. The choro was right up in the joint, so I'm going to go as high as I can. And this thing gives me a dome osteotomy, a curved osteotome based off the corner. I can distract using my fixator.
I can correct and then I can compress it and then I can percutaneous apply a slap muscular plate. And then we can come back and see that she's now aligned normally and heals, so that's just the technique of fixator assisted deformity correction. It's not an ex fix, it's a proper deformity correction fixator.
Going on, so this might be the sort of thing you could envisage in a Viva, and one of the things about the farke's exam is that there is huge overlaps in all of the tables in the Viva. What can appear in PEDs could also appear in basic science and could also appear in anatomy. What could appear in trauma could appear pretty much anywhere in the Viva.
And if you know your trauma. And if you know your anatomy. And if you know your basic science, I'm pretty confident you could pass the sharks Viva without much knowledge of actually any of the genuine pathologies, because almost all of the survivors rely on basic principles, which come from an understanding of basic science, anatomy and trauma, which can appear in huge amounts across the board.
So if you imagine you got this X right now, this could appear on the table. It could also appear on the our trauma table. You could have a vyver on the management of open injuries focusing primarily around the boat guidance. So you need to know inside out the first aid management of an open fracture doesn't matter if it's an adult or child.
You need to know your boast a nice energy. 37 guidelines for the management of open fractures and that's not the 2009 version, which was open tibia. That's now the updated 2017 version that includes all open fractures. You need to know about the antimicrobial prophylaxis, you need to know about the steps you need to know for anybody under the age of 16 that you have to mention non-accidental injury on the vyver table.
So this child may have been unsupervised, left with the front door open and has run out into the road and been hit by a car. So is there a social services circumstance, that sort of thing? This is a high energy injury because it's an open injury, so you have to have remember when we go back to what I call and I always tell my trainees these packaged answers. If I have a high energy trauma answer, there is always the well, so this is a high energy fracture, I would ensure the patient is managed as per its principles, the resuscitated as a whole.
Assuming there are no other issues or distracting injuries, I would manage the injury specifically. One of the things and the real techniques in vivas from my point is you take control. And that means you show the examiner that you've got confidence, not arrogance. Big difference. And you show the examiner you know what you're talking about by giving them enough information that they don't have to tease it from you, but also not wittering on so that you don't get to the valuable point scoring bits.
So here, if you're talking about managing the patient, assessing it, Yes. Don't sit there and go and assess them as ATMs and I check their airway, check their breathing, I'd feel that your care is central to their circulation. I get a couple of candidates because this is not an Atlas Viva. You can say I would assess and manage the patient as per its protocol and ensure they are adequately resuscitated.
And if the examiner wants in a fatal favor, you say, oh, right, what does the test protocol mean then? And he'll ask you, and that's where the Viva will go. So you've got to move it forward. You mustn't forget to say that stuff because if you don't say it, you can't get the marks for it. But you can say it in a way that intimates your thoroughly understanding of it and you know how to progress the VBA in a safe manner.
Similarly, all open injuries get the most for chat or periodic fractures get the. These are high energy injuries at risk of compartment syndrome, neurovascular assessment, blah blah blah. Anybody that goes to an operating theatre, you have a packaged answer, assuming the patient is adequately marked and starved and consented for surgery. I would place the anesthetized patient at appropriately on my board with an arm table, deploy the image intensifier, conduct the who out prep and rate, and ask if I can begin with you, Mr. Whatever your packaged answer is in 30 seconds that says I've got experience of this problem, I'm in control of it.
I'm going to take it forward with you, Mr examiners, so we can get to the high scoring bits. So here in an open fracture, you can imagine being asked about boastful, you can imagine needing to talk about how are you going to manage a patient, a child in a trauma situation? You might get the discussions around neurovascular assessment or compartment syndrome because it can occur in this.
You might get the discussion around management of this child with an external fixator. And then how are you going to put on an X fix? How or how are you going to definitive measures? Are you going to elastic nail it or what? You need to know those answers. The other thing that can happen in a trauma survivor or any survivor is you think you've finished your question and your case and then the examiner goes very good or whatever he says.
They don't normally say very good, but he goes, OK. End of that, Viva. Remember, you get three questions in your 15 minutes or whatever it is. And then they leave the same X-ray up and you're going, oh, what's going on here? Then something's about to happen. And he goes, so this child was treated with an external fixator, and one year later, he comes back to you because he's got some pain in his ankle.
And this is actually how things happen in my vyver. One of the tables I was asked to. Describe the surgical approach for drainage of a septic arthritis of a hip of a two-year-old. Perfectly reasonable basic science or anatomy question on that table. The congenital and then he said, how would your approach differ for congenital dislocation of the hip?
That was kind of the next few marks. And that was my first bit of the Viva table. And then he said, great. So now you've shown me how you can open up and reduce a hip? Yes now you're going to tell me you want to look at your open reductions and see how well they correlated with your ultrasounds beforehand. Can you tell me a statistical way of assessing that?
So it was the same topic it led on, and my next survival was how do you do 2 by 2 table analysis and stats? The same table, the same examiner, the same topic suddenly to survivors. So you need to be aware and prepared for that. And don't. Don't be afraid or alarmed. If that happens, it can do.
It's a new topic. It's a new area for you to discuss. So this kid, a year ago, high energy open fracture chats discuss them around that those four manage with an ex fix. Same child a year later, comes back with painful ankle. Now what are you going to do? Well, we're going to describe X rays, and when you describe X rays, you say what you can see.
This is an X-ray of a skeleton, the immature child of the distal tibia and foot and foot. I can't see a lateral radiograph. I can see that there's some sort of X or ptosis or bony protuberance in the proximal metathesis on the lateral side of the tibia. There is suspicion of some abnormality or asymmetry in the distal tibial thisis. I can't see any obvious fractures or other abnormalities, such as soft tissue swellings, tumors or similar.
I would like some more information and some further imaging. 30 seconds. I've said everything I can see, I've shown the examiner, I'm mature, I know what I'm talking about. I possibly picked up on something. He'll now tell me. And this, indeed in this case, is a partial physical arrest of the distal tibia.
And you might get another image that might show a CT scan or something with some arrest here, or you might get an MRI that shows a change in signal here. Or we might just say yes, exactly. There's a partial physical arrest there. How might that have happened? Well, it could have been from a pin. Placement doesn't look like the fix was near it. This was probably the pin track here.
It's probably from the injury itself. Hi energy trauma wouldn't be surprised if he'd smashed his face up a bit, and he's now got an angular deformity created because he's got unobstructed growth on the medial side of the tibia. But Fischler rest on the lateral side. The examiner, OK, is there anything you want to do? I take more history.
Exactly what are the symptoms? What are the problems? Has he noticed a deformity? Does he have any pain? I'd examine him for joint range of motion scarring because he's had a high energy, open fractures. You've got a leg full of skin grafts and I performed some more imaging. And here when we look, we can see just where we've gone back to our deformity assessment on this one.
The chora is located in the talus, not even in the tibia, and the angle from the Dome of the tolerance points to his other hip. It doesn't even point up the right leg, so he has a big deformity 11 or 12 degrees of acquired Vargas in the ankle from partial physio to rest. So the examiner may be really good. Let you go down the route of assessing that, or the examiner may present this to you and say yes, he's a partial progress.
It's got quite a big deformity. It's about 11 degrees. What do you think you want to do? And then you can have a mature and sensible discussion and you're into a really high end vyver now. OK, this is not your entry question of here's a partial physical arrest in the child who's yet not yet reached skeletal maturity. What are you going to do?
OK, so it's not your opening question, but you can take it and you can keep it really simple. You say, well. Firstly, I would like to quantify the deformity and the effect on the patient. I probably like to know the amount of growth remaining to see if there's going to be a significant increase in the deformity before he reaches skeletal maturity, or we think he's nearly a maximal deformity anyhow.
And then I'd like to assess the soft tissues, and then I'd like to counsel the patient as to the pros and cons of intervention. And at what time the examiners go very good. So, OK, he's not got a lot of growth remaining. We think he's probably only got about six months left. He's done most of his growth spurt. Mum's not buying any new shoes anymore. And what he'd like to know is, what can you do?
And then you can talk about principles of correction, gradual deformity correction, acute deformity correction and so on. And the Viva will go away. But by that point, you will be up at the 7 point mark. You'll be flying in a visor like that. So just to show you, this was a rule to correction again, another type of dome osteotomy, we've performed a sort of curve.
The curves are often not as big as you think they are. We've done a correction in theater using a hacksaw pod, so we've done an acute deformity correction, but with the benefit of external fixator. And the reason for that is he had a whole leg of skin grafting, so I didn't want to do any internal fixation on him. And he is now fully healed. So you can see now his joint is parallel to the axis of the tibia.
We've rotated, but he's got that bump we talked about from a rule to correction in kids. Obviously, they form a nice bridge of callus on this side and it'll smooth off. But he's got these bumps from rule to corrections or even in the fibula. Herro will three correction because of what we've had to do. Are I'll stop there.
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