Paediatric Basic Science: Bone Growth and Rotational Profiles



This on-demand teaching session will discuss the growth of bones and rotational profiles in pediatric orthopedic care, covering topics such as growth plates, remodeling of bones, types of fractures, and interstitial cartilage growth. Attendees will understand the diverse rates at which bones grow in puberty, the importance of understanding the structure of growth plates, bone types and growth rates, and how to equalize leg length in standard age groups.
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Bone growth

Rotational profiles

Guided growth & knee deformities

Muscular Dystrophy


Learning objectives

Learning objectives: 1. Describe how bones grow in terms of speed, length, width, and shape. 2. Contrast the growth of long bones Vs. flat bones. 3. Calculate growth rates for different parts of the femur, tibia, humerus, radius, and ulna. 4. Examine the consequences of growth plate fractures and how to limit them. 5. Differentiate between boys Vs. girls in terms of speed of bone growth and optimal timing for guided growth and epiphysiodesis surgeries.
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The following transcript was generated automatically from the content and has not been checked or corrected manually.

Oh, everything's gone. Very quiet and I don't know if you can. You now here. Perfect. All right. Okay. All right. Let's go, pediatric consultants. So, uh he's going to talk to us first this afternoon. Yeah, good afternoon, everyone and stand. Helen's hopefully going to come and join us later. But I've been asked to kick off the children's orthopedic after afternoon by talking about bone growth and rotational profiles and guided growth and knee deformities. Um So the aims of the talk, so that at the end of it, you'll be much more comfortable understanding how bones grow, what rotational profiles mean and why they're important, how he can use guided growth to try and correct deformities in Children while they're still growing. Um And you'll also be a bit more comfortable understanding the knee deformities that we think about in childhood that can be challenging. So if you think of bone growth, most of us think of the most significant bit of growth as being during the teenage growth. But, but it's not actually the case at all. The fastest age at which we grow during our lives is between the age of zero and five years then we get moderate growth between five and when puberty starts and then we get a slight pubertal growth bert, which is only about 10% faster than the five to puberty area. So most of the things where it goes wrong rapidly is going to be in the first five years of growth. So how does bone actually grow? Well, this is the boring bit that you might need to draw a picture in the exams or you might need to talk about it. Now, the image on the left shows you a kind of zoomed in version of what a growth plate looks like. So if you think at the very top is where your epiphany sis is, then the bluey bits down the middle are the cartilage and then the bottom is the metaphysics of the bone where you start getting bone and blood vessels. So you can see that much of the growth plate doesn't have any blood vessels in it. But the reserve zone where things all start does have blood supply. So the important thing to take away from this particular slide is that growth in the growth plate starts on the epiphany this side and slowly make stuff until it ends up on the meta facist side. And the reserve zone and the proliferative zone are the important bits because that's where new cells divide and start multiplying and making new bone. And then the hypertrophic zone which is further down the picture and closer to the metaphysis. That's where those cells mature, develop their structure and then turn into the mata fossas. And this is really important because it helps you to understand why some kinds of growth plate fractures are important. And other ones we don't bother much about. So if you think of your soul to Harris classification for growth plate fractures, um the most common one we see is a soldier Harris to and that's where you get a fracture through the growth plate that then comes out through the metaphor sis and because that fractures through the stuff that's already made and then comes out through the metaphysis, which is already made, it rarely causes damage to how you make new bone. And consequently, the chance of a growth arrest is much less in assault Harris to then in the other types. However, if you have a salt Harris three, which fractures through the metaphysis, it through the growth plate and then up into the epithets iss that's going to go through the reserve zone and the proliferative zone. So you're more likely to get a bony bar that causes permanent damage and shortening to that boat. Similarly, if you have a type four um salt fracture that goes through the metaphysis through the growth plate into the joint surface, then again, that crosses the reserve zone and the proliferative zone, that's how it's helpful to know the way in which this cartilage isn't just uniform. All the way across the epiphysis, uh quickly the fetal growth plate but actually has uh a structure to it with a particular order. Now, if we want to think about how bones grow a remodel, we can divide them up into long bones and flat bones. And you can see how if you say think of this as a femoral head and neck um got around blob at the top, which is your joint surface, your femoral head and bones not only grow by getting longer, using the technique use or on the left hand side by the epiphany, this making new stuff uh to the faisal growth plate, but we also have the bone getting wider. So as your um femoral neck and head grows, firstly, we see subperiosteal addition of bone on the outer side of the cortex of the shaft. And we have endosteal resort option of bone on the inner side. And that's what makes the shaft of the bone grow wider. The length as we noticed is due to growth in the growth plate. But also our femoral head needs to get bigger. So to do that, we get interstitial cartilage growth and epimysial endocardial growth. And then we've got to reform the shape. Otherwise we have a bone that's the same width as the femoral head all the way down. So we need to have finalization. That's when you get metaphysical resorbs shin of the bone so that it changes shape as well as getting longer and wider. And when you have funny shaped bones like the scapula, you get much of the blade making new bone from Subperiosteal edition. But you will also have the growth plates along the margins and along the bits that stick out like uh the, the acromion and so on where they'll have their own uh growth plate, their, their own Fyssas that allows the spine of the scapula to grow and so on. So, one of the important things about children's orthopedics is knowing how bones grow, what rate they grow, how much growth they've got left before you reach adulthood and what are the consequences of bad things that might happen to a growth plate? So if you think about growth in the legs, the femur at birth, it's about nine centimeters long. But by the time you're an adult, it's 45 centimeters long. So it increases its own length many times, the tibia and fibula are always smaller than the femur. They're about 80% of its length, right throughout childhood. And the proportion stays roughly the same. Now, the picture you got on the right is a useful way of helping you to remember how growth is not uniform in these bones, but it's more likely to happen at certain growth plates than others. So if you look at this area here under the limb segment section, we can see how in the femur, 30% of femoral growth comes from the proximal femur and 70% comes from the distal femur. So that's why if we're going to do ephemeral epic physio DCIS to try and stop growth and shorten that leg, it makes a lot more sense to do it at the femur femur distal end than at the proximal end. And it's also anatomically a lot easier to do it down here. Tibia is a little bit different. Growth is more even at the two ends, it's about 60% proximal end, 40% of the distal end. So again, if we want to do episode Asus to make the tibia shorter, we'd normally do it at the proximal end up here. Now, these figures here show roughly how much growth you get per year in a child, obviously does vary a bit depending on which age you are. So the one in brackets or when you're going through your pubertal growth spurt and this is in growth. So you can see how in a typical year the proximal female grow about six millimeters. Distal femur grows about 12 millimeters. A proximal tibia is about nine millimeters. Distal tibia is about seven and it's one or two more during the growth spurt. And so that's why Children orthopedic surgeons normally target the knee, the distal femur, the proximal tibia when we want to drill out a growth plate to try and stop growth. And it often gives you about two millimeters per year of correction a little bit more if it's during the growth, but it's about 2.5 centimeters per year and about two centimeters in younger Children. Now, the arms is a bit different. So you'd think the arms will work the same way as the legs do because they're just another limb. But unfortunately, it doesn't work that way. So, in the lower limb, most of the growth happens at the knee, but here only a bit happens at the elbow and most of the growth in the humerus happens proximately and in the forearm happens distally. So you get about 75 to 80% of growth in the forearm happening at the distal radius and ulna. And with the humorous, about 80% of growth happens at the proximal humerus. So that's why we don't normally drill out growth plates around here because it doesn't make any difference. Uh But because limb length discrepancy in the upper limb is much less of a problem than in the lower limb. If we are going to be worried about growth plates, it's more about making sure radius and ulna grow the same amount and one isn't getting longer than the other. Um And so that's why we often have to tinker with the distal radio on the joint if one bone stops growing compared with the other. Yeah. Now there's a important differences in growth by age. So we all know that uh at different times of your childhood, you're going to be growing different amounts but there's a difference between boys and girls on when that growth stops and that's because of when puberty happens. So this graph tells you how much growth is happening in the distal femur and how much growth is growing in the proximal tibia. And you can see that in most girls by the age of 14, their growth plates have closed. So that means there's no point trying to do guided growth or epic is EOD Asus to equalize leg length in a girl at the age of 14, unless they've got some reason why they're continuing to grow longer than we would expect. So if you need to do these things, you really need to do them at the age of 12 or at the latest 13, otherwise you run out of time. However, in boys, they keep growing on for longer. So most boys close their growth plates at the age of 15 and some will grow a little bit at the age of 16. So that's about 1, 1.5 years, occasionally, two years later than girls. So you don't have to do your um epic is EOD Asus to equalize out leg length as young in a boy than you do in a girl because boys will have 1 to 2 years, more growth in their legs than, than girls will. So that helps you to choose the timing of your surgery when you need it. So to summarize for your exam, the speed of growth at the different growth plates. Proximal femur is about six millimeters a year. Distal femur is about 12 millimeters a year. Proximal tibia is about nine, distal tibia is about seven and in puberty, it's one or two millimeters faster than that each year. And those are some basic numbers that you might be asked about in the exam. If you have someone who's got 33 centimeters of leg length discrepancy and somebody says, what age do you think might be a good idea to correct that with an Epic Ezio DCIS, I draw going out a growth plate and what growth plate or growth plates would you choose? Which is a perfectly reasonable exam question for them to ask? And if you know those kind of, it's it's a perfectly reasonable exam question for you to get 100% on and feel confident and move on to the next part. So why do all these growth plates and things matter? Well, if you've got leg length discrepancy, you want to know when to do a drilling F F is owed Asus. So knowing about the age of the growth plates closing is important and how much they're going to grow at each growth plate. It's also helpful to know when growth is going to stop at growth plate because it helps to reduce the risk of recurrence of certain kinds of, of deformity. So if you've got a deformity and a child, which is triggered by them growing and then you do a bony correction. Um, and then they carry on growing and part of the, the benefit from that surgery has been lost, then you feel a bit frustrated. So if you wait until that bit of the body stop growing, then you can then do your surgery and there's less likelihood that that deformity will recur. So knowing, um that okay, this is a girl, I can do this operation at 14 because their growth plates will be closing. Then means I can then and plan at what age I'm going to do certain things. It also helps you to avoid surgery that won't work because there's no point doing guided growth. Uh if growth isn't going to happen anymore, so you're not going to get enough correction, you're going to have to have been that idea and just go for a corrective osteotomy. And then we need to think about the consequences of growth plate damage. So if you've got a nasty fracture or if you've got uh Osteomyelitis where an infection has damaged the growth plate, um you can calculate what the likely consequences are going to be depending upon the amount of growth that you've got left. So on the right here, you can see a bony bar crossing the distal radial growth plate, um and that's going to cause tethering. So the bone uh is going to continue to grow on the radial styloid side, but not on the distal radio on the joint side. So it's going to cause tilt and it might find it causes shortening of the whole bone as well. So if you then know what age are they going to stop growing at this growth plate, how quickly are they growing? How many millimeters per year at this growth plate? Then you can think, okay. This child's eight, I really need to do something about this because the risk is going to go badly wrong. Or this Charles 13, there's not much growth left at all. I don't really mind. It's all going to disappear quickly. And so I can leave it well alone now. Not all parts of the body stop growing at the same time. And one important thing is about compared with the lower limbs, the feet stop growing earlier. So in general, girls stop growing in their feet at the age of 12 and boys stop growing in their feet at the age of 14. So that's about 1 to 2 years before you find the case in the lower limbs where girls normally stop by 14 in the legs and boys normally stop by 15 or occasionally 16 in the legs. And that has implications for surgery you might want to do on the foot without recurrence happening because it means that you can crack on in a 12 or 13 year old girl knowing that if you make a good correction to a problem that they have it's hopefully going to stay so long as they don't have ongoing neuro muscular disorder. Okay. So now we talked a little bit about growth before we go onto rotational profiles. Does anyone have any questions that they want to ask me? And can I actually hear any of you asking questions or do I have to stop share ing to get any questions out of you? You can still, you can get questions even though you're, you can't see anybody piers. I think you should be able to hear us, but I don't know whether anyone there's nothing in the chat so. Okay. Okay, thank you. Which is wonderful. Uh Let me ask a question. That's okay. Yes, of course. Uh When a child has a fracture saying the femur, how much extra growth do you expect them to have? How do you calculate that? Now, that's a different question. I very carefully didn't cover that in the talk because you're making a big guess. So uh if you get shortening from a femur fracture, uh people always say, oh yeah, it'll grow out a bit with time because of the increased blood supply as a result of the healing and that has some merit. Um I haven't specifically seen if there are any papers to look at how many, how much regrowth you get. It often does happen, but it's not meant to be a very predictable thing. It depends how much injury there is. It depends where the fracture is. It depends how old the child is. So, yes, you do get some regrowth. But no, I can't tell you how much you're gonna get. Sorry, I don't know if Helen has an answer. Have you ever read a paper telling you how much you're going to get after a femur fracture? Uh No, I haven't. I'm saying is you actually, I think your answer is very good peers. It's, you know, a bit excellent. Yeah. Right. Any other questions or shall I move on to rotation? Perfect. Okay. If you do think of something, I'm very happy to answer it later. If you're just grappling with how to get your microphone to work, right? When we think about rotational profiles in the lower limb, most of what we're looking at is in the femur and in the tibia. But you do have to remember you can get rotational deformities within the foot and things like that too. I'm just going to concentrate on femurs and tibias to get the concepts across. So clinically, how do we assess tibial torsion and femoral Torsten? Well, um as you can see from the handsome lad on the left here, the best way is to slap your baby down on the couch or your older child lie them on their front and then you bend their knees up at 90 degrees and you put the knees together and then you see what direction the feet point and that um tells you that how twisty your tibias are. So, in other words, the tibial torsion now for that to work, you have to have normal knees and normal ankles. Um, and then you have to look at where the foot points. But if you have a funny shaped foot disregard the forefoot and just look at where the hindfoot points. But if you have a normal shape foot, then the whole direction of the foot will help. But some Children do have quite flexible mid foot, hind foot and ankles and you can wiggle the direction of the 4 ft around. So what you really want to do is make sure the hind foot is in neutral at 90 degrees at the ankle and look at where the hindfoot points and that will tell you the tibial torsion. If you then want to look at the femoral tajin, what you have to do is rotate at the hips by keeping the knees flat on the bed and then moving your hands out towards the side, rotating at the hips. And if you've got femoral ante torsion, sometimes called femoral ante version, then you'll find that the legs go flat on the bed and the feet point straight out sideways. And then when you try and go the other way and cross your hands so that you bring the legs together, you find the legs don't cross very much. So that's a sign that they've got anti torsion or anti version in the femurs. However, if you've got the opposite, so you've got femoral neck retro version. So your femoral next point backwards, then you find that the legs don't go out to the side very much at all, but they cross loads and they will go all the way on top of each other. So you can swing them across. And that's how you tell clinically whether someone's got anti version or anti torsion in their femurs or retro version. Now, these, this is probably one of the most helpful slides you will have for understanding gate. And that's to think about the Staheli rotational profile because there's a lot of rubbish that is said about this to parents. And if you know what these grabs are and how things change over time, then we can make sure that we're actually telling parents what's going to happen to their Children. So if you look at the top left hand graph, this tells you where your feet point when you walk and that's called the foot progression angle. And the foot progression angle, you can see from the horizontal line down the middle, the average foot progression angle where people walk is about five degrees of external foot progression angle. So instead of their feet putting forward, they find a little bit out to the site. And if you notice that does not change with age, so from the age of one to the age of 15, that's the average thing of where your feet point and the normal range is from about 15 degrees of external foot progression angle. So your feet pointing outwards to about 10 degrees of internal foot progression angle with your feet pointing inwards. So a lot of toddlers do have in toeing and do trip over their feet. But the first thing is not to tell the parents that the in toeing will disappear as they get older. Because as you can see from this graph at the age of one or two, you've got what you're going to get as a grown up. So that misnomer that these things will wear out and disappear and come back and see us if they haven't gone by the age of six or something, it's all codswallop and that's why you get so many worried parents coming back to see you at the age of six and you say I'm still not going to do anything about it. It's normal. So if you remember that you've got a 25 degrees range of variation in your foot progression angle, that's completely normal and it's completely normal to walk within towing, then you can reassure a lot of people. The important thing is that little kids who innto trip over their feet because they brain doesn't know where their feet are. They don't have spatial awareness of their feet. Whereas as they get older and their brain develops, you find that you do develop spatial awareness of your feet And so the tripping disappears even though the in toeing does not. So that's the important conversation you need to have with parents who are worried about tripping and in toeing how you can explain it's normal how the tripping will go away. But the actual foot progression angle does not go away. Then if you look sorry, I've just got a question, sorry to interrupt. Can can the kind of progression angle move within that graph or does it stay stable? Well, Staheli didn't specifically talk about that to my knowledge. Um And there are later grass where you see a line wiggling up and down that shows that you can get variation, but this is just the normal range. So, um, no, you may get variation within the normal range and it may be that some people move from being more innto to out toad or out toed to in towed as they get older. But if something is in the normal range, I still regarded as normal and I'd be fairly chilled about it. Okay. Thank you. Okay. So, although the foot progression angle doesn't change and the normal range doesn't change their twists in your tibia is in the fema's, they do change. But what you find is that one twist in the opposite direction of the other, so that over time they council each other out and that's why you end up with normal foot progression angle being the same even though you can see curves in the graph on the top, right and the bottom left and so twists do change, but the actual foot progression angle doesn't. So the 5 ft angle that you see top, right, that's your tibial torsion. And what you can see is that up to the age of five, you get some change there. But after the age of five, it tends to flatten out a fair bit and certainly by the age of 10, nothing much changes after that. And the same happens with your external hip rotation bottomless. So what you're looking at is the way the femur is twisting, that it changes a fair bit in the first 5 to 10 years. And then it seems to slow down after the age of 10. So this is quite important for those of us doing femoral or tibial D rotation osteotomies because if you do it under the age of 10, you might find you've done a good job and then they carry on twisting and by the time they stop growing, they've either under corrected or over corrected. The deformity that you thought you'd fix. So that's why it's best to try and delay tibia. And femoral D rotation osteotomy is to at least the age of 10. So that you're likely to keep the same rotation by the time a child is an adult, right? So hopefully looking at these graphs and understanding what the normal ranges are, helps you to get a better idea of when to follow up a child and when not to bother to and when to reassure the parents that they're well within the normal range, it's fine. You can go home now. Thank you very much because about half of the referrals that we get to children's orthopedics are from GPS or health visitors or physios not knowing these graphs. Right. So how does talk shin cause pain? Because it's very rare for me to operate on torsion if it's not causing pain, unless it's something about affecting their physical ability to walk, such as in Children with cerebral palsy where you might have such abnormal biomechanics that the exercise, uh tolerance of that child is affected by having crazy to wash in and they don't just have the strength to cope. But most of the time I'm going to correct caution, I'm going to do it for pain. So the important things are that the hip is a ball and socket joint so that rotates easily. So if you have a lot of femoral tor shin, you can rotate at the hip and compensate for it. Although by the end of the day, some Children find that their hip muscles can no longer keep that hip in a compensated position. So they often find that a child may tip may into more at the end of the day than they do in the early part of the day because their hip muscles are just too tired to bother to compensate. However, the knee and the ankle joints are hinge joints and they cannot compensate by rotating like the hip can and consequently twists are much more likely to cause pain. It twists in your tibia than they are in the femur. So what we find is that the location of the symptoms often depends on the way the child walks. So if you had external tibial torsion, for example, so if your knee and your foot say 0.45 degree different angles, if you walk with your knee pointing forwards and the foot pointing out to the side, you may well have foot pain, you may have tibialis, posterior tendon attachment pain. You may have ankle pain, you may have shin pain, but you don't get any pain. However, if your parents talk to say you've got to walk with your feet pointing forwards, you look silly with them pointing out to the side, then your foot is in a biomechanically normal alignment. And so is your ankle, but your knees pointing immediately. So it's much more common to get patellofemoral joint pain because your knee is not pointing in the direction it needs to. And that's sometimes called miserable malalignment where you have a hip and the knee pointing in the right direction. So hip and a foot point in the right direction but the knee pointing immediately. So how do we treat torsion or malalignment? Well, you treat the pain and not the parents so you don't have to be average to have a normal child. So you don't have to have a five degrees of external foot progression angle. You can have 10 degrees of intoeing or 15 degrees of out toing and still be normal. And so if a child's happy with the way they walk and they're not in any pain, it really doesn't matter that the parents badger you saying there's something wrong with my child's legs, as I mentioned earlier, the in toeing, that means that you trip over your own feet as a toddler goes away as a child gets older. So that by the time they're a teenager, they will walk with the same foot progression angle, but they're not tripping anymore because your feet just know how to miss each other when you walk. If I'm going to do a femoral D rotation, osteotomy, which generally is if a child has groin pain or thigh pain or buttock pain from abnormal Federal Torsten, then I would get a CT scan to help me understand the true torsion alignment. So some people can eyeball it know based on their clinical assessment or based on rotating the hip and feeling when the greater trochanter is most prominent. But I find that I'm not very accurate at doing that and I might be 10 or 20 degrees out. And so I get a CT to have a look, I find tibial D rotation is much easier to do clinically because unlike the hip where you got the ball and socket joint that can rotate, you can fix the knee and you can fix the ankle and look at it and work out the rotation that way. So I don't bother doing CTS for tibial D rotation, although some people do. But for the reason I said earlier about how certain uh joints, how hinges and certain joints of ball and socket, I find that I need to do far more tibia D rotations than femoral D rotations. And so I probably do 20 children's tibias before I do a femur. Just because family D rotation seems to be less necessary. It's less likely to cause pain because you can cope better with it. So how are we going to look at the CT scans? So when you book your CT, you need to tell in your request exactly what you want. So you say you're doing it to calculate the torsion um al alignment in the femurs, say in your request, I'm going to look at it and calculate it. The radiologist doesn't have to do it. And what you want to do is say I want to have some cuts of the proximal femur and then I want you to keep the legs in exactly the same position using a gutter or some foam wedges. And then I want them to have some cuts of the distal femoral condyles. And then I'm going to calculate it. And if they do that. Then you don't get someone that's got, you know, three D reconstructions and horrendously over radiated pelvis is by having, you know, imaging that they didn't need, you don't need to see t all down the thighs and see the shaft. You just need the femoral necks and the distal femur. So you get less radiation. Um, and then how do you do it? Well, you need to compensate for them, you know, make sure that they're nice and flat and so on. Now I do uh these arrows on here using my computer because I couldn't get the ones from packs to give me the picture. But if you draw a line from one side of the pelvis to the other, that gives you your, your baseline to show you where is flat just in case the child's a little bit tilted, then you draw a line up the femoral neck towards that where the head is. And then an angle between that and that is how much anti torsion or anti version we appear to have at this point. And that would be plus five degrees because it's pointing forwards. Minus it was, if it was pointing backwards, then you go down to your slices at the knees and you draw a line at the back of the femoral condyles and do that compared with the horizontal. And here you can see how, although that's pointing forward a little bit, these are very much pointing internally rotated to this side is minus 27 degrees. So if you look at plus five to minus 27 you can see there's a total of 33 degrees of twist in this particular femur. And if you do the same for a tibia, which I don't normally do. I do it clinically. Um Now these lines, it would only let me do it at five degree increments. So that's not quite on that back cortex. I'm not trying to cheat or anything, but it just wouldn't let me go any more accurate. But that one at the tibia along the back of the condyles, you got about 10 degrees of internal tilt. So that's minus 10 degrees. And if you draw a line across between the middle of the two parts of the medial malleolus and lateral malleolus, it doesn't matter what the taylors is doing. You need to draw the line between the middle of that bit, middle of that bit. So that's 45 degrees of external orientation. So minus 10 plus 45 you've got 55 degrees of external tibial torsion. So in this child, I would do a tibial d rotation on this leg, but I would probably leave the femurs because 30 degrees isn't that horrendous. Um But if the only problem was their hips and if they genuinely had groin pain, then you, some people might do a tibial D rotation osteotomy. If you think the average femoral ante torsion is about 15 degrees, then 30 degrees and 33 degrees is only about 18, you know, 18 degrees more than that. So I would regard the tibia as the main cause of, of uh problems in a this set of imaging. So how do you then do a D rotation osteotomy? So, if you're going to do the tibia, uh I would always do it distantly and not proximately if you do a proximal tibial D rotation osteotomy, and you go from external to internal that cause uh traction across the common perennial nerve as it goes through the femoral uh around the fibula neck. So I would always do a distal tibial D rotation osteotomy if you can. Um There are different ways of doing it. Some people put plates on. Uh I use a technique where they're left with no metal and I can do it through about five centimeter incision. So it's nice cosmetically, simple thing to do. So I do an answer. Remedial dis uh incision where all you've got there is a saphenous vein and saphenous nerve. So you're not gonna prang any tendons or anything like that. Um I use X ray to identify the growth plate and then I aim to do my osteotomy just at the top of the syndesmosis. Um And I split through the periosteum and keep that as a nice sleeve. I repair at the end. Um I under X ray guidance, I um put, brought home and retractors to go around the back of the bone, but inside the periosteum. So I don't want anything cutting the bone to whiz out the back and damage stuff, neurovascular injury. And I'll drill for your four holes a parallel across the distal tibia and then I'll join them up with an osteotome. Um, and the advantage of an osteotome over a sore is firstly, it doesn't cause heat. So, unlike a sore that might kill the osteoblasts at the end, you know, by your, your um osteotomy. Secondly, um if you come out the back with an osteotome, it will push your nerve and artery away. If you come out the back with a vibrating sore, it will sever your artery and nerve. So I always use an osteotome because it feels safer to me. And I try and protect everything in the back with border tractors and also drilling a row of holes means that you end up with a sort of jaggedy edge of like M or W shape. And when you d rotate, you can then get more stability because you move the m from one side into the next slot along effectively. Um And then I passed a couple of K wires up the medial malleolus. Um but don't cross the osteotomy site, I then d rotate. So the foot is in the right direction relative to the knee. Um and then feed my K wires up across into the metaphysis. So it comes out through the proximal cortex and then check, I've got my alignment right, check the osteotomy is in a good alignment and then I know it's nice and safe and then I'll put in uh them in above knee cast for six weeks and I can take the K wires out under entin oxidation in the plaster room. And then they left with no metal work and they've only had a five centimeter incision, but you can do it with a plate. And that has the advantage. If you use a locking plate, you can get the person weight bearing on there. Um And they don't have an above knee cast. So it's a bit easier for, for looking after yourself and getting dressed and all those other things. But you do then have a big plate that you either take out a second operation or if they're 15 and you don't think they're going to need it removing. Um You still have a plate which some people find when it gets knocked under their scar, playing sports and things. Some people find a plate a bit uncomfortable. And of course, Kyi's are a lot cheaper than a plate. So there are many reasons why uh if you can avoid a big plate, why not? If you're going to do a proximal femoral osteotomy, then I tend to do that just around the level of the lesser trochanter. And I would use a proximal femoral locking plate. But you can also use ephemeral nail. Both of those allow you to weight, bear afterwards with some crutches to steady yourself. I certainly find a, a proximal femoral locking plate is a lot easier to remove because ephemeral nail, sometimes the head can get covered over with bone. And obviously, femoral nails sometimes affects the uh ability of the abductors on the greater trochanter to, to work well. And some Children might have a bit of a limp. And so using a proximal femoral locking plate leaves all your hip muscles intact. So I, I personally find that an advantage. Okay. Does anyone have any questions about uh rotational profiles and how we would treat those? Investigate those and correct those? Um Mr Mitral. Just a quick question on your correct a rotational deformity on femurs. Do you ever use um sort of guide wires on the side to determine your angles when you're on your rotation or? Absolutely. So I would calculate the amount of D rotation I want to do based on my CT. Then I would uh open up my osteotomy site and then I'd fire in a choir uh across the femur. And then I would use a sterile protractor and I calculate the angle that I want to de rotate by, by using uh that sterile protractor. And then I fire in the second wire and then I make my osteotomy and then I D rotate the leg until the wires are now parallel. And then I put on my plate with it held in that position. Um The other way of doing it is with the femoral nail, but of course, can't put the wire all the way through the medulla, then you can only put it through the outer cortex. So it's a little bit less clearly held. But if you're using a locking plate, then you can put in those, those wires through both cortices and they're more likely to uh remain accurate and not, not get dislodged or become loose. Uh I had a question about femoral um Sesame's as well. Do you, would you ever do it for um patellar instability? So it all depends where your abnormality is. But uh if you had an outrageous femoral alignment, then yes, it could be helpful. But most of the time I find patellar instability is related more to whether you have valgus at the knee, whether you have a laterally located tibial tuberosity, whether you have a flat dysplastic femoral notch or a deep notch and whether you have external tibial torsion. Um But if you found all those other things were normal and if they did have a crazy femoral torture, then yes, you may need to do that. Um But uh I think especially because your correcting it proximately rather than distally um uh quite a bit of femoral instability in the femur is related to how the quadriceps pull on your patellar. So you could argue that you really need to do a distal femoral d rotation osteotomy to correct for uh torsion or malalignment in the femur because of the way the quadriceps are going to be pulling on the patella. If you correct it, approximately two where a big chunk of the quadriceps have already attached, you know, like your assets intermedius and things, then you have this issue that you might d rotate the femur, but you'd still have an abnormal pull of your quadriceps onto the patella and you might find that it wasn't quite as good an outcome as you hoped it would. Mhm. Okay. Thank you. Uh Mr Metro had one other question about your distal tibial uh irritation. That's okay. Do you, do you have a limit of how far you can rotate it? Do you have to routinely do a fibula osteotomy alongside it or is there you can rotate before you have to, before you can leave it alone or before you have to do a fabulous year. So when I started, I was doing fibula osteotomy and I put a K wire up there and then I went to a conference where someone says, no, you don't actually have to do the fibula. It's in the books, but I've never found you needed it. So, about 12, 13 years ago, I stopped doing fibula osteotomy is and just rotated the tibia and they're absolutely right. It works fine. So I, I don't ever rotate the fibula or, you know, or osteotomized the fibula anymore. I just do the tibia, as you remember from those previous rotational profile graphs, it's normal to have external tibial torsion of up to 30 degrees. But so the patient's I operated on your, your generally looking at about 45 50 degrees of external tibial torsion and then you can swing them back to a, to a more normal figure. And I have no problems rotating the foot by 45 degrees, swinging it back to pointing forwards and it always seems to work fine. Just buy d rotating on the tibia and not cutting the fibula at all. That's great. Thanks a lot. I also had some question if that's okay for the, this to uh tibia Austell to me and the K wires you might, I might have missed if you said the size of the wires, if you go by cortical, if it affects, if you know, do you do that for all age groups? And how long do you keep the wires in? So I always use the biggest K wires we got. So I used, used to millimeter K wires. I used to use one of them. Uh And over time, I've got progressively more into just using too because some kids are fine with one and some kids ache a bit. Um So I always put in two wires up the medial malleolus. When I first started, I tried to give more stability by putting an anterior wife. You but I haven't bothered doing that for ages. I don't think you need it just as long as you've got to sort of divergent wires up the medial malleolus that uh no, don't, don't they sort of spread out across the meta facist to give a bit more stability um coupled with the fact that in Children you close the periostem e you know, it's a lovely sleeve that's three or four millimeters thick. You make a longitudinal incision through it. Do your operation and stitch that up, that gives you an extra level of stability at the osteotomy that you don't get when you're operating on adults. I tend to take the wires out about six weeks after surgery. Um, occasionally they can just start walking, but most kids would need a walking boot for a few weeks after that just to give them a bit of support while they get used to walking. But once the wires are out on the cast off, I start physiotherapy and get them doing exercises at that stage. Thank you very much. Any other questions? Okay. Wonderful. So let's think about angulations, deformities. So that's where if you look in one plane and you see it's not as straight as it should be. And the common ones that we see here are Valgus knees or knock knees, you see on the left or various deformity at the knees or bow legs as you see on the right. So, Valgus where your knees touch and your ankles don't. And various is where your ankles touch and your knees don't. But you need to remember that you can be fooled into thinking someone has valgus deformity at the knees when they actually have obesity. So if you have a lot of soft tissue on the inner side of the thighs, the actual bones maybe in a straight alignment, but the ankles won't touch because there's a lot of fat between the thighs. And that can give the appearance of valgus, knee. So sometimes you do need long legs, standing x rays to tell the difference. So this again is one of those really useful graphs that helps you to remember how Children should grow normally and when you can relax and when you need to be worried and it's the kind of thing you might potentially be asked to draw in your exams. So the uh uh access along the bottom shows how age changes over time and on the other access, we have various and valgus, you can see how up to the age of about one year babies, how bow legged they have various deformity in their legs. And then they swing into valgus between about 18 months and the age of seven or eight and then passed the age of eight. Then you may get a bit of movement, bit of various bit of valgus. But most people are roughly looking at a straight pair of legs. And this is really important for understanding when not to panic because all babies have bow legs. So you shouldn't think. Oh, I've got a one year old with bow legs. Maybe they got rickets or something. It's normal to have bow legs at that age. And then you get these panicky people saying the legs used to look all right. But now they've got knocked knees and my child's three. And again, you can just reply to the GP referral on Raz saying, you know, that's completely normal. You know, talk to me again at the age of eight if they've still got bowlegs, but it's normal to have it at the age of 345, don't worry about it. And that's because growth at the distal femur growth plate isn't even, it grows more on the medial side and more on the lateral side depending on the age that you are. And that's why it swings from various to valgus like this. So this is a very important thing for also remembering um why Children get deformities of certain kinds. Um So for example, if you have rickets, you're going to talk a little bit about later. So you've got vitamin D deficiency, for example, um if you develop that vitamin D deficiency at six months of age, and then if the child starts walking at 9, 10, 11 months, then that's when they will be in various naturally and their bow legs will get worse and worse because of their rickets However, if they only develop their Ricketts at the age of three, when they've already got into valgus, then the Ricketts does not cause bowlegs. The Ricketts cause worsening. Valgus deformity at their knees. So that's why we find with metabolic bone disease is where you get abnormality in the way the bones grow because the bones are too soft and not mineral izing properly. The age of onset of that disease affects whether a child may present to you with markedly bowlegs or markedly knock knees because it all depends at what age the child was at what they're normal physiological alignment was before they then start going crazy with their malalignment due to their bows, not mineral izing properly. So this is what bow legs looks like. So you can see a little toddler on the left with bow legs. And the way I used to identify bony alignment is to do a long leg standing x rays, draw a line between the femoral heads and the talus and then see where it goes. And in a typical adult, it should normally go through the middle third of your knee. Um, as I mentioned, at different ages, it may go to the medial part of the knee or the lateral part of the knee, but it should never be flapping around in midair unless you've got a pathological problem like you see with the x rays in the middle. Um And then if it's a physiological problem and you're just patient and you wait, you end up with a child like they are on the right. So how do you tell the difference between physiological bow legs and pathological bowlegs? Well, in physiological bowlegs that Boeing is shared between the femur and the tibia, the x rays all look normal. So you don't have pathological flaring of the meta faces like you're getting Ricketts and things like that and you don't get medial be king of the proximal tibia like you get implants. Um But if you have all the deformity happening in one place, for example, the femur looks normal, but it's all at the proximal tibia. Then that's when you know it's not pathologic, it's not a physiological bowlegs. You know, there's a pathology at the proximal tibia such as with blanks. So what are the most common causes of pathological bow legs? So you can see those x rays on the right. Those are crazy legs. If you draw a line between the femoral head and the taylors there in midair, that's not a physiological thing. If you look at the actual shaft of the tibia and the femurs, they are very curvy. So this is not just physiological, this is clearly a pathological set of legs. Um When I was at your stage, people used to say, oh, vitamin D deficiency is really rare, but it's on the list. But you know, it's much more likely to have these congenital genetic problems such as excellent hyperphosphatemia and so on as a cause of Ricketts. However, now we're testing vitamin D much more commonly. Um, what we're finding is that quite a lot of kids come to clinic who have bone pain and you test them and they might have vitamin D levels of 10 or 20 in animals, pill ito and 15 animals per liter and above it is normal. Uh, and some of these will have abnormal phosphate and calcium and some may not. Uh but I think by the time you're at 10 or 15 or sometimes so low, the machine can't tell you what it is. And I think that's when you're going to start getting abnormal bones and not just aches and pains in your bones. But there are genetic causes such as excellent hyperphosphatemia and renal tubular abnormalities where you can have adequate levels of vitamin D, but you get bow legs because your bones can't use it properly or other parts of the vitamin D production pathway. Um So these are genetic and, and congenital problems. Uh That mean that your body can't handle, it's vitamin D and it's calcium properly. Another common cause of bowlegs. Other skeletal dysplasia is um most of us in the region have a bunch of families where all their kids have similar problems. Um It can be quite challenging when, if someone who has a skeletal dysplasia tends to marry someone else with a skeletal dysplasia because they then find they're the same height and they have the same approach to life and you don't have that discrimination problem of having a 6 ft husband and the 3 ft wife and things like that, they might meet at a conference or something along those lines. Then you can get a complex mixture of skeletal dysplasia is where the kids may have genes of two different skeletal dysplasia from their parents. And that can make it even more complicated as a children's orthopedic surgeon. Um but uh dysplasias such as metaphyseal, oh, chondrodysplasia will eat a very beau legs where you have curvy, femurs, curvy tibias and uh the line between your Taylor's and your femoral head is definitely in the air and not anywhere near the joint. Then another condition to think about is Blount's and Blount's disease is where the proximal tibia has the disorder and the femur is fine. And what you find is the proximal medial part of the growth plate stops growing and the lateral part keeps growing. So you get a progressive angulations at the proximal tibia leading to bow legs. I'm going to tell you a little bit more about that in a minute. So, remember that Ricketts is an inadequate mineralization of growing bone and it can uh either be due to vitamin D deficiency or it can be due to genetic disorders that mean you cannot process your vitamin D properly or utilize your vitamin D properly. So, how are we going to correct uh bowlegs. Um if it's not physiological, but it's pathological. Well, um if someone's already closed their growth plates, then you have to use an osteotomy. So, this girl on the left, I had to do an opening where the osteotomy their femur uh and that was because they had Ella's Danlos syndrome and they had valgus knees, they were dislocating there. Patella multiple times a day and they only came to see me at the age of 50. And I did say, why didn't you come to see me when you were younger? I could have treated this with eight plates, but they didn't. Now, the good thing about Children is that you can do an opening wedge osteotomy and they do fill in the gap with bone, whereas in an adult, it may not heal. So you often have do a closing wedge osteotomy and remove a bit of bone and that leaves them with a shorter leg. Um However, the simpler way of doing it is to tether growth on one side of a growth plate. As you can see with the right hand X ray using an A plate or a staple. Uh There are some parts of the body where some Children orthopedic surgeon just pass a screw across the growth plate on one side and not on the other. And that tethers growth and then that leads to growth on the opposite side, but not on the side. That is being tethered by your piece of metal. And the advantage of that is firstly, there's minimal blood loss. Unlike an osteotomy, you only need a small incision. You don't need a big plate. They can go home the same day. It's a day case procedure. They can just walk out if it's just 18 plate like this. They normally don't need crutches, they can just get going. Um And you end up with a four or five centimeter incision at most. It's implied under X ray guidance to make sure that you uh straddle the growth plate nicely and that your screws are in the right place or a sensible length. Um And then that stays on the surface and over the next 69, 12 months, you gradually get growth until you get the correction you want. Um So you have to see them every three months. It's really important. They don't get lost to follow up otherwise they will overcorrect and end up with a banana leg the wrong way. So I make a little list of Children that have eight plates and I stick them on my desk in my office and I make sure that I am seeing them and that they haven't been canceled because there's been a strike or something else. And then it becomes a six month follow up rather than three months and then it might all go wrong. Guided growth only works for single plane deformities. It can't correct rotation. So that's why D rotation, osteotomy is needed, but they're very good for single plane deformities that you can use them across the front of the knee, but you obviously can't go under your patella. So you have to put them aunt er immediately and anterolaterally on either side of the patella, femoral joint. So that, that way you can correct and enter a poster, a plane tilt. But they're more commonly used for medial or lateral plane and you can put them on the female. You can put them on the tibia. I have read about them used on the proximal tibia at the femoral. So a proximal femur at the femoral necks and I have tried them a couple of times in skeletal dysplasia is with kids with various femoral necks, however, they didn't work. So I had to take them off and do valgus osteotomy because some Children with skeletal dysplasia will have very various femoral necks and that's not good for your femoral heads or your growth plates. Um But it may be that other people are more talented at this or it may just be that the individual skeletal dysplasia I used it with just don't really work very well for uh a guided growth up at the femoral neck. But this is the difference between osteotomies and using guided growth. And then once the leg is straight and you've clinically got the correction you want, I would get long legs standing x rays to biomechanically confirm radiologically that it is. Right. And then I plan to take the plates out, uh, and not leave them for a long time on the waiting list. They need to be done within the next few weeks because you don't want an over correction. Uh No, if you've got tens, tens nails after a forearm fracture, that can wait a few months without too much problem. But you don't want to leave this on your waiting list. Otherwise they will overcorrect while you are waiting to do their operation. So, Blount's disease, as I mentioned is where you get a problem at the proximal tibia on the medial part of the growth plate and sometimes it's unilateral, sometimes it's bilateral. Um and there are two main types, infantile blount's and adolescent onset, blount's infertile, blount's tends to happen in kids that work that walk earlier than average. So if you remember that, um if you, if you start walking at the age of 9, 10, 11 months, you're probably going to still be in various because that's when you should be embarrassed and then the weight will go through the medial side of the knee more than the lateral side of the knee. And sometimes that crushes the medial growth plate stops, it growing. The lateral side keeps growing and you get a progressive Boeing. However, this is also more likely to happen if a child has obesity because the forces going through our just hire was if a child only starts walking at 18 months, then they'll probably be in neutral or valgus by then. And consequently, uh they're much less likely to get compression on the medial side of the knee. It's going to be through the center or the lateral side of the knee. And so later walkers don't get blount's. It tends to be the earlier walkers, especially the overweight ones are going to get infantile onset blount's then adolescent onset blount's again, more likely in, in people with obesity. Um and it's where the growth plate on the medial side gets crushed and gets sick. Now, the X ray you can see on the right here, you have to remember that in one and two year olds, much of the knee is made of cartilage and not of bone. So this isn't all empty. What we're looking at is a growth plate across here, an epiphany sis across here and the actual cartilage you'll see running around there like that and the proximal tibial cartilage will go across to there and down like that. So if you MRI them, you'll see the growth plate goes across this way and then seems to fold down um because it's just not growing high enough and that's why you get this tilt. But there is epiphany sis here made a cartilage. Um And so how are we going to treat Blount's? Well, the treatment's going to be different in infantile than adolescent. So if you get your child under the age of three, they have very malleable knees. They have lots of plasticity. So in the way we can treat little babies with club foot using weekly cars. We put Children with infantile blount's into Valgus knee braces. So they'll have a hinged knee and then they'll have little sandal AFO type things that go around their feet and then bit that go around the thigh and it's basically tries to force the knee into valgus. So it's no longer into various and they see the orthopedist on a regular basis and they adjust it a little bit to give more valgus till more valgus tilt. And then by offloading the medial side of the knee and putting more weight through the lateral side of the knee, normally, the growth plate of the proximal tibia on the medial side, wakes up, starts growing again. And after a year or so you end up with a reasonably straight pair of legs. However, sometimes it doesn't work, especially in the obese kids. So I had one recently, he was so overweight, he that she would break the brace metal, uh and she would have tantrums and would not wear her brace. So in those kind of cases, sometimes you're still going to need to do surgery in this age group. However, in teenagers, you can't put them in braces like this, they've got too much bone, they're growing more slowly and uh the braces aren't going to work very well because a lot of them are overweight. So one way is you can put eight plates on the lateral side of the proximal tibia leaving the medial side free. Now, that has the advantage of a slow and gentle correction. But if we've got a problem where there's no growth on the medial side because it's all crushed and then you make them no growth on the lateral side with your eight plate. Sometimes nothing changes. Or if it does change, it could take a very long time to change. Um So another option if you aren't getting that is to do an acute correction with a proximal tibial osteotomy, just distal to where the patella tendon attaches. So you don't damage that growth plate. And then you can put some cross K wires across the proximal tibia. And that way you can then put them in cast and then you get an acute correction rearrange the biomechanics. It's not an enormous incision. And that can be another way to fix Children that uh eight plates don't work or if you think there's too much deformity. So eight plates you think aren't going to be able to do the job because the medial side of the growth plate is already not working. So we were asked to cover knee deformities. So another thing would be sensible for you to have heard of is congenital dislocation of the knee. So this is happens in about one in 1000 individuals like so one in 100,000 individuals. So you think a lot of things that go wrong in kids like club foot dislocated hip stuff like that is about one in 1000. This is one in 100,000. So it's much rarer. It seems to be sporadic. It's not one of those things that runs in families where everyone says, yeah, I was born with that. Um And you can grade it in into three versions where you either get A was where you have hyper extended knees and they just don't bend properly. B is where you start to give subluxation of the distal femur on the tibia and C is where it, the distal femur is completely dislocated off the back of the tibia. Um The treatment for this depends on how stiff it is and what type you've got. So type A and B we can often do cereal casting where you put them in above knee cast and bend the knee a little bit more each week and that will flex out the knee. However, type, see, you probably have to take them to theater, do an arthrogram. Try and reduce the femoral head back onto the, onto the a proximal tibia, put them in cast. And then once you've got them into a better flex position, then you can manage these babies in a Pavlik harness where it keeps the knees, hips, knees and hips flex, but allows movement there. So you start to get uh restoration of the length of your ACL and the meniscus shape and all those things that you want that are clearly not going to be right in a type. See there the, the internal soft tissues of your knee or going to be deranged. So if you can have them in for a few months in a public harness, that can be a good way of making the knee more stable. However, sometimes the type see you just can't reduce and you need to take them to theater, open it up. Um and do do an operation to, to reduce that and then try and place them in a, in a safe position of flexion but not something that most of you will see very often. I've only seen one. Okay. So hopefully, now you're all much more confident about bone growth. We've talked about how bones grow in length and how they grow in width and how they remodel and how groans grow differently if you're a long bone compared with, if you're a flat bone, we've talked about how Children of different ages will grow at different rates. We've seen how growth plates within the same bone will grow different amounts. And we've explained the differences between the lower limb and the upper limb. For example, most growth in the lower limb is at the knee was most growth at the upper limit's at the shoulder and at the wrist. And you've seen how we can apply this to epic physio DCIS surgery to correct leg length discrepancy and how we can apply this to when we would do surgery such as guided growth. We've then gone on to look at rotational profiles. So hopefully, you understand what normal ranges now for Children and what abnormal ranges for femurs and tibias and also for the overall foot progression angle that results from femurs and tibias. Hopefully you understand about miserable malalignment and how you can get symptoms in different places on the leg depending upon how a child chooses to walk. Even if they may have the same abnormal twist as another child who just chooses to walk differently. You've seen how we can correct rotational profiles with tibial osteotomy is and femoral osteotomies and the option we have for how we might fix those. And this is obviously something you can do regardless of whether someone has growth plates or not, however guided growth where we correct single plane deformities such as various or valgus at the knee. That is something that we need to still have open growth plates for because it relies on tethering growth on one side of a growth plate while leaving continuing growth on the other. So the diet both clearly has many advantages over using an osteotomy. Um But there are certain times when it doesn't work very well. For example, in bad cases of blount's where there's just not much growth going on anyway. And you've got to follow them up like a hawk and make sure they don't overcorrect and don't get lost to the system because, uh, some Children are more, have more reliable families than others. And sometimes the system does mess up your, your clinic ability to see people regularly. And if you don't take responsibility for checking on these Children, if they have a deformity as a result of that, it does end up being your fault even though it was just whoever canceled your clinics fault. So you have to take that extra responsibility yourself. Then we've talked about need deformities that you might come across in the exam or in clinic. So hopefully you'll know about differentiating uh physiological bowlegs from pathological bowlegs. And you see the kind of imaging that we use, especially standing long leg A P X rays. So you can use scan a gram CTS to look at leg alignment. I find that much less use than standing long leg x rays because A CT you're lying down. And so you don't have the weight going through the legs at the same time. Whereas standing X rays you can allow for rotational torsion, you can tell the radiographer I want the feet pointing forwards or I want them pointing 45 degrees out to the side. And that way you can allow for Torsten make sure your knees are pointing forwards. And that way you end up with, with, with meaningful um imaging. Um We talked about different conditions be they related to Ricketts, be they related to the skeletal dysplasia is and I haven't gone into too much detail on the different types because I know that's being covered in a later talk in this series and we've introduced Blount's to you explained how that condition happens and how you can get it at a young age or a teenage age. And the different treatment options that seem to work quite well and what their limitations are and when we might need to do surgery because the bracing hasn't done the job? Okay. Now, does anyone have any questions about this part of the talk? Um I have a quick question. Uh Luke and one of the registrars. I don't know when I was in Cambridge on call, I went, I got called to go and see a neonate that had knee hyperextension and I seem to remember it's about 20 degrees of hyperextension and annoyingly, I can't really remember what I did after that. But um the pictures that you had of the knee hyperextension is that, are you making that call on clinical examination? Ultrasound? MRI uh how are you deciding whether there's a tibial subluxation anteriorly or dislocation anteriorly versus just, yeah, being in joint and hyperextending. So, the tricky thing is that the age when babies are born, they don't have very much bone in their knee. So you might have a specific Luke Lius or you might not. So it's really based on how the knee feels. So you can put your hands on the front of the joint and the back of the joint gently feel around the tibia and the femur gently flex and extend and see how they seem to be orientated. So, one good thing about a newborn is they're not generally enormously fat yet. And so you can feel the bones fairly well. Um, but yes, you could get an MRI or you could get an ultrasound, but it does depend on your hospital and a lot of hospitals would say I would have no idea what to do with the ultrasound. Um, and you could go with the ultrastenographer and say you scan the side of the knee and I'll have a look at the pictures and that way, that's one way around it. And uh MRI obviously will tell you if it's a A B or C, but you may well find that, you know, it looks like an A in neutral and if you lift up the heels, it looks more like a B because you're hyper extending and it then looks worse. Um And to MRI, someone of that age, obviously, you're gonna, you might find you can feed them unwrap and just let them fall asleep or you might find they need a general anesthetic if they're not in the mood. So another way of doing it, it was just to take them to theater and do an arthrogram. So if you inject them napalm or omnipaque die uh ending under general anesthetic. Then that will show the true surface contour of the femur and the tibia. Uh and that will then allow you to work out what's going on. You can then try and reduce the knee with more control because you're not accidentally going to snap off the end of the femoral cartilage or something. Um And then you can get a better idea of a good position of stability without subluxation when you put your cast on. So I would say type A is you're not going to need to go to deter, you can just gently flex it a little bit more each week and it's going to be fine. But if you're looking at a type C or a type B that might stumble up off the back, then you might want to take that theater. Do the arthrogram have a bit more confidence on what's actually going on? Thank you. Probably need to see one again, Mr Mitchell. Do you mind if I ask with your opening opening where just opening osteotomy? Do you have a limit of how much deformity, angular deformity you can correct you ever have to do in stages or um it very much depends on the age of the child. Um And whether there are neuro vascular structures that are intimately associated with the bit you're doing. So, um the last complex opening where the osteotomy as I did were actually in that two year old with Blount's who had a congenital obesity. So they weighed the same as my 12 year old son. Uh and no one could work out why. And the braces weren't working and the legs were just crazy bent. So I thought there's no way I'm going to be able to fix this with eight plates. So I did proximal tibial osteotomy ease. And I uh I rotated the distal fragment about 45 degrees relative of the proximal fragment and held those with K wires and uh no neurovascular problems because you split the periosteum and you protect the structures around the back with the periosteum and then realign your legs so that there then straight. Uh and that worked fine, but you wouldn't be able to get that much correction in a 13 year old because the soft tissues wouldn't allow you to. Um So yes, it's very much a matter of the age of the child. And also if they have a, you know, the Ehlers Danlos Children will be bendy A and will allow more correction than someone who doesn't have a connective tissue disorder. Uh and therefore will have more soft tissue tethering to limit what you can do. But also more in terms of the because they're obviously with an opening, you'll have a bit of a bony defect there. I mean, even in this diagram, obviously, it's only probably about 2020 years degree osteo opening osteotomy does is there a limit. Could you do say 30 40 degrees opening? Where draw is that, would that be too much? So, if, uh if they got open growth plates, you can certainly do more than if they've closed. Um But uh your options are to put some bone graft in there. You can, you know, take it out from the metaphysis of the femur. Um Or you can borrow a bit of the pelvis, uh put it in there or you can obviously use a synthetic bone graft if you like. Um And you've got to remember that teenagers do heal hugely better than grownups do so I can get away with osteotomy is in this age group that know adult surgeon would think about would be a good idea. Um And you know, so far they have all healed. So it does seem to be something that works. All right. So I think the main thing you have to be concerned about is, is the angulations of your osteotomy going to cause neuro vascular damage more than is the angulation of the osteotomy not going to heal. Uh But certainly you can poke some bone in the whole to help things to heal. That's great. And you need to use the appropriate metal work for the age and weight of your child. So in a two year old, you bung in some K wires in a 15 year old if you're doing an opening where the osteotomy. Yeah, you're going to need a locking plate. But, you know, in six months that was all solid bone and it had healed up very nicely. Awesome. Thank you very much. Hi, Mr Mitchell Iggy here. Um Hello, can I ask about? So when, when I worked with you, we use a lot of the um 369 mils. Um So we, we, we judge it by age and then 14 and 16 in puberty. I think that's what most commonly, what people do. So mostly charts and paley methods, do we, is there a role with them or? And is it expected for us to use those uh charts? Um Yeah, someone saying 3 69 mils about how much growth you get in growth plates. Yeah, rather than using mostly charts or any kind of other fancy ways of calculating. So the amount that you get in growth plates. Yeah, you're right is often quoted as 369 mils, but that's just to help you remember it, it's not actually right. So this is the data from sort of children's orthopedic text that, that seem to be a bit more evidence based and obviously it varies with your age, but it's rather know there's more growth at the distal tibia when you look into it than I learned as a 369 mill thing. Um But it's right in its order of how much growth there is, but there's actually more at the proximal femur and distal tibia than was tour in the 369 thing. But also don't, don't forget um Iggy that um when you know, when people are talking about the middle s rule of thumb, when you're then talking about congenital limb deformity, where you're trying to predict how much the limb length discrepancy is going to be. So for example, charges born with amphibians, hemimelia or some reason why one limb is shorter, you cannot use the minimalist rule of thumb to gauge what the limb length discrepancy is going to be. And people make that mistake over and over again when you quiz them on it. So just being very aware if you're going, you know, um the majority of us I think probably use Paleo. Don't uh the other chart that don't piss. Do you use the Paley App? Um You, I've given up. Yeah, I find that Children are sufficiently different that using a mean such as that is lulls me into a full sense of security if I think that the normal range of variation of leg length discrepancies about one centimeter anyway. And if we don't bother trying to correct anything that's less than two centimeters because people don't really notice it. Yeah, and that gives you a certain amount of flexibility on what you're going to do. And then you've got graphs like this that give you sort of prediction's as to how long people are going to grow for. But obviously there's a bell shaped curve and, and, and different people are different and you can pfaff about with hand x rays and putting them on a growth chart and you still find that you're at least a year of variability out with all these so called clever techniques. And if you just think if you, you know, if you're going to be a centimeter too long or a centimeter, too short, it doesn't matter because they're not going to tell the difference and they're gonna be functionally fine. I find that removes a lot of stress and unnecessary calculations. Um And uh if you start looking at, you know, obviously, if you've got five centimeter difference or something, that's slightly different. But if you've got a child with two or three centimeter difference, you can start looking at these charts, say okay, you're a girl. If it's 12, I've got three centimeters to short out sort out. If we, I'm seeing you now and you're 12, you're probably going to get 2.5 if I just do your femur, which is going to be about right. So let's just do that. But if they only turn up when you're 13, you think, oh, I got to do your tibia and your femur and it'll probably be about right. But as a result, all those things about getting hand x rays and trying to use apps and plot them on growth charts and see how tall their parents are and all that other kind of stuff I haven't found is made me any more accurate about these kids because you've got that degree of play where if it's one centimeter shorter than the other side or one centimeter longer than the other side, it's still within the one centimeter normal range. So does it matter about all of that? And you could argue it probably only matters for the exams and it's not as important for clinical practice because you've got that, that flexibility in the actual outcome where the child is completely oblivious to whether they're half a centimeter short or half centimeter long because they feel fine, they walk with a normal gait and they're doing all right. And the only way you can tell the difference is if you, you know, start imaging them and then you think, well, what's most important with medicine is a child who's pain free and has function and clinically, you know, is doing well, doesn't have to have any auth Asus or any treatment. And that's all, you know, so that, that, that, that's made me less interventional over the last 15 years of trying to get all those tests and things done. And now I'm less fussy about it because I don't think it makes as much difference as some people might tell us. Yeah. And there certainly is every few months as a paper, isn't there in a pediatric journal trying to tell you another predictive method for, um, when you can determine limb length of when they're going to finish growing or how you can, how you can um how you can plan for when, when they're going to complete. So, you know, your crystal ball um and a lot of methods are much from muchness, I suppose, from an exam point of view, which I think a lot of our, our audience are thinking of it from is, is just making sure you have an understanding of what the theory is behind. So how you're going to create your prediction. But as I said, I'm only saying this because I quit a lot of people on the same question and got people got in the real tangle when they were trying to talk about predicting what a big limb length discrepancy was going to be by starting trying to talk about what normal growth is, which of course, isn't going to be helpful when you're, when you're looking at a congenital deformity. Absolutely. I can't see any other questions in the chat. Do grill Mr Mitchell? Because there was a brilliant talk on uh everything you need to know about, about growth and uh abnormalities. And he's absolutely right. We uh clinics are overrun by rotational abnormalities and uh and worried parents getting GPS and A hps to send their, the uh the patient's in to, to us to get reassurance. So knowing um the normal variance is really, really important. May I ask you one more question of course. Sorry. May I ask one more question? Yes, I, I just was wondering with the type three dislocations of the knee, you said that often you cannot reduce it closed. And I was wondering if, are there like with a hip mechanical blocks to reduction? And do you need, when you take them to see if there's, do you need to release anything or is it just general contractors and just doing it in a more controlled fashion? So it does depend how complex your child is. And if this is their only problem or if they actually have other stuff like arthrogryposis or something, which is going to give you stiff unhappy joints right across your body. Um But if it's just the knees, uh then normally with a bit of traction, you know, if you pull down on the tibia and pull up on the femur, then most people can get the femur back on the end of the tibia. The problem of course is you may flip the meniscus or the meniscus may not be in the right place or it may not even be there and there are other complex things that can happen. Um And if you can't reduce it, you know, then it's an anterior incision where you can put a mcdonald's or something down through the front here, slide down there onto the back a bit like a shoe horn to get a tight pair of shoes on and then you can slide the femur upwards on your mcdonald Retractor and that will help it to slide on to the front. But this is not common and it's not going to be passed, fail in your exam. And although it's an interesting thing, you know, many of you will never see one, so I wouldn't get too stressed about, you know, it's not something that you're going to have to deal with on call on a Sunday as an encore consultant. Uh It's something that many people would just refer on to a specialist unit and say these, you know, I got a type c send it off to Great Ormond Street or Sheffield Children's or something. I can't reduce it myself. Can you sort it out, please? And then that's absolutely fine. I remember the first time a dental knee dislocation. I saw her as a registrar and I was asked to come to the neonatal unit and it looked like the leg has been put on the wrong way around. And it was terrifying because it really, you can't recognize it as a knee and it looks, it literally looks the wrong way around. And so go where the foot was the wrong way around on this knee. It was all quite sort of terrifying. Thank you. No problem. Excellent. I think. Is there any, any other questions? Fantastic. Thank you so much. That was, that was brilliant. My pleasure. Lovely to talk with you all