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The Management of anterior knee pain in the skeletally immature patient



Join Mr. Mitchell, a renowned pediatric orthopedic surgeon at Urgh City Hospital, as he enlightens medical professionals about diagnosing anterior knee pain in adolescents. In this informative session, he will detail his insights into the biomechanics of knee pain, differential diagnosis, imaging, and the value of operations. Attendees can expect to delve deep into common causes, such as growth pain, torsional malalignment, Osgood-Schlatter disease, and patella maltracking. Moreover, he will demystify medical myths and equip you with practical instructions on patient assessments and treatments. Don't miss it!
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Soft tissue Injuries

Learning objectives

1. Understand how to diagnose anterior knee pain in adolescents and consider common causes. 2. Understand how to analyze and assess differentials on the basis of factors such as patient's age, sex, biomechanics, and physical activities. 3. Review and discuss pediatric orthopedic cases related to anterior knee pain and be able to recommend appropriate treatment plans. 4. Understand the importance of imaging in diagnosing knee pain and be aware when its use is most beneficial. 5. Understand torsional malalignment and biomechanics in the context of anterior knee pain and learn how to assess these situations properly.
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The following transcript was generated automatically from the content and has not been checked or corrected manually.

The next thing I don't know what to do is how to make that full screen. So it won't go full screen unless you press view full screen. Uh but it's, it's helpful in the sense that you can see the chat, you can see faces and, but yeah, and then you've got the top left right button to go, uh press left and right. So do you see it full screen? Yeah. Well, if you want to do full screen, you can press your full screen. But um we can see we can see your slide clearly. Ok? It's, it's just a matter of whether they're big enough to, to see what's going on. But if, if this is what you expect and this looks fine, then I will leave it as how you recommend. Great. So it's a pleasure to welcome Mr Mitchell who is a pediatric orthopedic surgeon at Urgh City Hospital. He's also the best of uh uh research uh chair and he would enlighten us on anterior knee pain in this immature patient. So long as I can work out how to progress my slides. So you what Nikki, there's an arrow if you hover over the slides, there's an arrow that you can take. Gotcha. Wonderful. Thank you. So, um, love to chat with you all this afternoon. Um, the aims of this talk are to help you with how to diagnose anterior knee pain in adolescents. Um, because there's a whole heap of stuff that goes on at the front of the knee. And when I was a orthopedic registrar, the adult knee surgeons would sort of have a quick look, rely heavily on an MRI almost MRI everybody. And then if the MRI was normal, you might get a scope just to have a look or they might not. And if they didn't know what was going on, they'd refer to physiotherapy. But hopefully, by the end of this talk, you'll realize that we could do a little bit better than that. And whether you want to do kids or whether you want to do adult knees or anything else. It's really useful to actually know how to assess someone, how to examine them. Think about the differential diagnosis to know whether imaging is a good idea, to know whether operations are a good idea. So hopefully, um the myths will all be revealed shortly. Unfortunately, it, it took me a decade or two before I worked it all out. So the factors that are really helpful in coming to a differential diagnosis uh in adolescence are firstly the age because uh you know, in, in kids, different conditions happen at different ages. Secondly, the sex is really important because we find that um certain conditions are much more common in one sex than the other. The biomechanics are important for helping you to understand why pain may happen. Even if the examination may otherwise be normal, you may get, you know, no effusion in the knee, you may have a normal range of movement. You may have a normal MRI and it's actually pain from the biomechanics rather than the knee itself being a problem and how certain physical activities are very good at triggering off knee pain, especially anterior knee pain. So taking a sensible history and finding out what sports people do really does help you narrow down what's likely to be the problem. So the common causes of anterior knee pain in Children, uh very common one is growth pain. We've got torsional malalignment. So twist in the femur and the tibia odds Slatter disease and Sylar and, and Johansen disease, which are both sports induced tendon inflammation syndromes that we see in teenagers. There's patella maltracking and then a more extreme version of that where you get patella instability and osteochondral injury that may follow from patella instability or may be due to direct blow to the knee or other trauma and medial plica impingement, which was the most popular diagnosis I came across when I did adult knee jobs during my registrar training and they were whipping these out like anything especially privately. So hopefully by the end of this, you'll know when it's a real condition that needs treatment and when it's something that should be left well alone because it is a normal bit of anatomy. So let's think about gross pain first of all. Um although we grow at the fastest rate as a teenager, uh as a percentage of our body, it's between the age of one and eight that we're growing the fastest. And so that's when kids tend to present with growth pain. So it's quite common between about one and five, but it can go on to about the age of eight, it can be unilateral, but in a lot of cases, most cases, it's going to be bilateral because you grow in both your legs at the same time and they tend to present with pain in the knee and in the shins. And uh the kid will rub on the front of their knees and in the upper part of the shins when you point to where does it hurt? You? Question. Um It can happen with pain at night that could wake them or it can be a first thing in the morning thing cos they've been growing at night and then when they stand up and walk around, then it starts aching and a few kids will have their main problem at night, but may get aches in the day as well, especially when they do physical activities. So the reason is the bones grow and then the soft tissues normally stretch to cope with that. But in this portion of kids, it seems to hurt when those soft tissues stretch out. And that's what seems to be the growth spur pain cause. So you want to make sure that they don't have Vitamin D deficiency. And then if you're pretty sure there is growth pain based on the history and the examination, basically a normal examination, then you can treat this by getting the parents to stretch out the soft tissues in the knees and the hips and the ankles. If a child waits in the middle of the night, at the age of two or three, they can do some stretching, they can do some massages, they can try and distract the child with a story or playing some music. There's not much point giving paracetamol and Ibuprofen because it takes half an hour to work. And by then the kids always fallen asleep. So if you can avoid medications that that's better and reassure them that it's likely to get better uh with time. So whether you want to do blood tests to check their Vitamin D or whether you want to just recommend that they are on some multivitamins that contain Vitamin D different consultants will have a different preference that way. So now we're going to talk about torsional malalignment and biomechanics and how that can cause anterior knee pain. So, um those of you that came along to the pediatric er session when I was talking about torsional malalignment will know all about this. But I appreciate some of you may have been away or on leave or generally just couldn't be bothered to listen to my talk. So the important things about anterior knee pain is you need to walk with your knees pointing forwards. And if you don't, if they put medially or laterally, that's commonly cause it's anterior knee pain. And so a common cause of your knees not pointing forwards is if you've got abnormal twists in your femurs and in your tibias. So we normally refer to twists in the tibia as a tibial torsion. And a lot of people refer to twist in the femur as as femoral version, but some people also call it femoral torsion. So, in an adult, you expect a sort of average of, of femoral neck to point forwards by about 15 degrees. But of course, there's a big range in Children and there's a big range in humans in general. Sure. So, torsional malalignment, it is a complex thing to examine and to identify and most torsional malalignment in the femur doesn't cause hip pain because your hip rotates easily because it's a ball and socket joint. So you can sometimes get groin pain or buttock pain or pain going down the thigh from a big twist. But a lot of the time people compensate, um but they can't compensate in their knee and their ankle because they wear hinge joints and consequently, you're much more likely to get pain in your knee or your ankle than you are in your hip if you've got these twists. Um, and one classic phrase that you'll hear being used is, um, the miserable malalignment syndrome, which is where you have twists in the tibia and in the femur, we'll talk a little bit about that in a minute. So how do you assess tibial and femoral torsion to work things out? Well, firstly, you want to see the child walk and look at the direction their feet point and look at the direction their knees point and you may see their knees pointing uh medially and their feet pointing forwards. And that gives you a red flag that, that, that, you know, there's some twist going on. If you actually want to work out the to twist in a bit more detail. If you lie, the child on their front, bend their knees up at 90 degrees, then you can look at where the feet point there to assess the tibial torsion. Um And you can see from the pictures on the right, whether you've got external tibial torsion or internal tibial torsion, then you can rotate at the hips and put the legs out to the side. And if you rotate the ankles out to the side and they go flat on the bed, then you know, they've got femoral anti torsion or femoral anteversion because if they don't go out very far but come together a long way. So you can cross the legs over immediately, then, you know, they've got retroverted femoral necks. So these are the normal ranges for torsion. It's called the Staheli rotational profile. And you can see on the top left, 1 ft progression angle. So basically, your foot progression angle is from about 10 degrees of internal uh foot progression angle to about 15 degrees of external foot progression angle. So you've got about 25 degrees of normal range. And if you want to look at the tibial torsion, you want to look at the picture on the top, right? And you can see how there's a, a quite a big uh change between younger childhood to older childhood. But by the time you get over the age of 10, when most of the twists don't happen anymore, the body's changed. Um You know, it, it, it, it's fixed the twist that you have in your tibia and your femur and your torsion is gonna be what it's gonna be as a grown up. You can see that torsional torsion in the tibia varies from about 10 degrees of internal tibial torsion to about 30 degrees of external tibial torsion. So if that's the normal range, that's quite big, isn't it? So you only really want to be doing torsional malalignment corrections if you're well outside that range. So if you've got say 45 degrees of external tibial torsion then you can be fairly confident that you're correcting abnormal to normal. But remember by looking at this slide that you don't want to do tibial det osteotomies to correct these things uh when they're too young. Because if you correct someone that's got funny shaped legs at the age of five, you may find that by the age of 10 they carry it on changing and then you need to uncorrected what you did at the age of five. So if you can wait until the age of 10, before you do tibial derotation, osteotomy, or femoral derotation, osteotomies, you're much more likely to find that you've got a long standing good correction and not one that then changes, right. So if I'm doing, if I've got knee pain due to femoral torsion, then I always get uh CT scans cos it's quite hard to assess the twist in a femur because it's a ball and socket joint, it's much easier to assess the twist in the tibia clinically. So if you lie someone on their back in the CT scanner and scan their hips and then scan their, the femoral condyles distally. Uh and you make sure they don't move their legs. In the meantime, you just get actual cuts. This allows you to then template and look at the twist. So if you draw a line between the post part of the pelvis, uh and then you do a line up the femoral neck, you can see that you've got about five degrees positive. So five degrees of anteversion in the femoral neck on this side. But on the same leg on the knee, you've got 27 degrees of internal twist here. So if you've got minus 27 here plus five there, overall, your femoral torsion is going to be 33. And if you do the same for tibia, which I don't normally do because, um, once I've started doing this in the first five or six, I found that the scans showed me the same as my clinical examination. So I don't bother doing scans for tibias anymore. Um If you, if you look at the back of the tibial condyles, you can see a minus 10 degrees as in a little bit of internal torsion. And then if you draw a line between the middle part of the fibula and the medial malleolus and you measure that between the horizontal do that you make on the back of a a can, you've got 45 degrees plus there minus 10 there. So altogether you've got 55 degrees of external tibial torsion. So this is a child that's got a big twist that's well outside the normal range. And if they've got anterior knee pain and maltracking pain, then correcting their tibial torsion is likely to be helpful for them. So how do you treat torsion or malalignment that's causing knee pain? Well, um what I tend to find is I may if I have got 20 Children that I do derotation, osteotomies on, I'm likely to do about 19 of them will be tibial and only one will be femoral because of, as I mentioned, the hip coping much better and the knee and the ankle not coping. Um, miserable malalignment syndrome is where you have femoral anteversion and um external tibial torsion so that you uh point your feet forwards and your knees point medially. Um So things that you want to do, the simple things you can do for anterior knee pain due to torsion are firstly to make the child walk with their knees pointing forwards and then tell them what direction their feature point. So some may point medially, some will point an external foot progression angle. Then physiotherapy can be helpful to improve the patella tracking. And then if that doesn't get things better, then that's when you want to do derotation osteo to correct the alignment. So the ankles and the knees and the hips all point in the same direction. So how do you do a tibial derotation osteotomy? Well as in orthopedics, there's always several ways to do something. Well, the technique I use is with a distal tibial derotation osteotomy because if you do things proximally and you internally rotate proximately, then you can cause common perineal nerve um injury as it goes around the femoral neck. Cos you don't want to tighten it with your osteotomy. Secondly, um I use an anteromedial approach to the distal tibia just superior to the er, syndesmosis. Um You want to put retractors around the back of the tibia so you don't damage in your vasal structures back there. Uh I'd never use a sore across the distal tibia cos if you come out the back, you can whip through everything. Whereas if you make a row of drill holes and then use an osteo tone to join them up, then you can then correct the alignment um and then stabilize it. And I would use two K Ys and some people use a locking plate which is absolutely fine, but you then have to have a second operation to remove it and you have a much bigger scar. Whereas if you use a couple of K wires and a small approach like this, it's only five or six centimeter incision, cosmetically, it's very good. You take the K wires out in clinic in the plaster room and with some Entonox and then they don't have any metal left and they don't need a second operation to remove things. They do need an above knee cast. But if you're a child and you've got parents to look after you, it's not a problem being in an above knee cast for six weeks. So the next thing I want to talk about are the sports induced tendon inflammation syndromes. Um So Oscar Slater's disease, um this is uh a condition where it's the tibial tuberosity that hurts. So, um, with any, er, assessment of a child's knee, you want them to point with one finger to where it hurts. And that's really useful to help identify the differential, uh, cause and they point specifically at the tibial tuberosity. It's in, you know, in a teenager it's very likely to be os good slater's disease. So, it tends to happen in those aged 10 or older and it's sports induced, particularly in football. It's really common for football to be one of their popular sports. They often do sports every day of the week. They don't have rest days and this can trigger the inflammation that they have. Now, the X ray on the right shows the classic signs that we're looking for. So you can see widening of the growth plate underneath the tibial tuberosity compared with the proximal tibial growth plate. You can see the inflammation is actually triggering new bone forming in the patella tendon. So sometimes these things will be reported by radiology as fragmentation of the tibial hypophysis. It's not fragmentation at all. What it is is inflammation triggering extra bone being laid down in the tendon. And you often see a more prominent bump at the front because the inflammation triggers uh extra bone to be formed. And clinically, they often have more prominent tibial tube, rosti. It may be tender to examine on the tibial tuberosity as well and find it sore to kneel down. So the key thing you want to do, you want to check the Vitamin D levels because obviously, if you've got low Vitamin D that increases your chance of getting bone pain and correct that. But if the Vitamin D is normal, then the mainstay of treatment for Children with Oscar Slater's disease is to rest from sport for about three months. And the significant majority of Children will settle down and then you can reintroduce sport maybe one day a week and then do that for a few weeks and then maybe twice a week, making sure you've got rest days and then gradually introduce. However, um, some Children never settle down or if they do settle down, they then return to pain when they restart their sports and that's when surgery can be helpful. And, uh, Miss Latter and I are doing a, um, a prospective study of a surgical treatment that we have for Oscars latter disease, which you will all be doing in a decade's time. But we do have to follow the kids up until they, um, um, finish their growth, um, to be absolutely sure that it's a nice safe procedure, but it is a procedure that seems to work very well. But, uh, you won't need it for your exams cos no one else knows about it. So, from the point of view, exams, uh, there is no really effective surgical treatment other than some people, you know, try and take out these articles and things like that. But it's uh there's no proper randomized trial to, to show that those surgical treatments are any more helpful than hocus pos. So I wouldn't go poking around on Children with Oscar Stat's disease. But you're very welcome to refer your patients to us uh and send them to me at Peter and I can sort them out if you want or send them to me at the. Yeah. So uh another common uh sports induced tendon inflammation syndrome in teenagers that gives you anterior knee pain is sending glass and Johansen disease. Again, we generally in those aged 10 or older sports induced. And you can see from the MRI here, uh you get inflammation at the lower pole of the patella and the attachment of the patella tendon onto there. So you can differentiate this from other conditions because when you get them to point with one finger, they specifically point at the lower pole of the patella. Sometimes it may be associated with inflammation in the fat pan underneath, as you can see with this particular MRI. Um But again, the mainstay of treatment is to check any, you know, check for Vitamin D deficiency and treat that and then rest from sport for some months. Um If you send Children with sending Lase Johansen or Oscar flatters disease to physiotherapy, they will see them and they will start some exercises. But there's really no good evidence to say that physio is of any benefit. Um And the key thing is this is a sports induced tendon inflammation syndrome. So it seems crazy to me to then go and get their knee doing loads of exercises because the whole point is it's triggered by too much exercise. And so I recommend rest and I don't go down the physiotherapy route. Um, but uh, you will get different opinions from different people as to whether physiotherapy may be helpful. But there's no good studies to show that it is now a common cause of anterior knee pain. And probably the most common I see in teenage girls in my elective clinic is patella maltracking. It's much more common in girls than in boys because girls do have stretcher connective tissue than boys do. And that's why they can do crazy things in gymnastics that I cannot. Um It tends to be in the over tens. Uh So you don't get patella mal tracking in five year olds even though they're grown quickly, uh They tend to present with painful locking and clicking. So it's interesting a lot of things in the knee that lock like a loose body or an ACL rupture that's flopping around. It should be painless but painful locking in a teenage girl is basically patella maltracking until proved otherwise. And the finger test is really helpful because if you ask them to point with one finger to where it hurts, they point down the medial border of the patella along the inferior side and up the lateral border of the patella in au shape. And this is really classic for patellofemoral joint pain symptoms. And it's due to an uneven quadriceps, muscle pull as they go through their growth spurt. So you tend to get uh vastus lateralis, pulling on the patella more than vastus medialis. Some kids will be predisposed to it by having a flat notch. So, trochlear dysplasia, although uh uh it's uh most kids will have a normal notch who do have a patella maltracking problems. And this, you want to correct any biomechanics that you see. So if you've got crazy tibial torsion, or if you've got crazy valgus knees, then or if you've got a laterally placed tibial tuberosity, then no, that group may need surgery, but most who have normal biomechanics will get better with physiotherapy with Vastus medialis, obliquus strengthening exercises. And I normally recommend about 15 minutes of exercises every morning and every evening, about three months. And then when the symptoms settle down, I recommend they carry them for on for at least a year afterwards. Otherwise they'll come and see you a year later saying my symptoms are back. And I say, when did you last do your exercises? And they'll say when the pain went and I'll say, well, that's your own fault, isn't it? So, if you have that conversation in advance, then they know to do it for longer. So I don't normally take people to the theater straight away unless they have crazy legs. Normally they go to see the physios see if we can get them better by altering their gait and their uh foot progression angle. So their knees point forward by the physio VMO exercises and then I'd only take them on for surgical derotation and so on if the physio doesn't help them to get their symptoms better. Now, the extreme consequence of patella maltracking is when your patella doesn't track at all over the front of your knee and keeps dislocating so many er, girls that have this injury because it's much more common in girls than boys. It's from a particular catastrophic injury when they're playing netball or something like that. Um, and um, again, it tends to be in the age of 10 and above. Uh, there's no need to put them in casts when they come to A&E, they obviously need some crutches to help them walk. They will have a big he arthrosis. Sometimes they come in a cricket bad splint that they can use for a few days to help them weight, bear hinge, knee brace would also be fine. Um, what you want to do is once the patella is back on the front of the knee, you do physiotherapy for vma strengthening exercises, stop them doing sports and things for, for a couple of months and then once they can run comfortably and their exercises are going well, then most kids will settle down and then they don't have any further dislocations. However, if you have recurrent dislocations, say 34 or more, uh, then this is a group when, uh, we'd normally intervene with surgery and you need to assess their biomechanics and find out what the cause is. You know, and if they've got bad tibial torsion or if they got a laterally placed tibial tuberosity or if they got a valgus knee, then you want to correct those. So valgus knee, you'd correct with medial eight plates until the legs straightened out and tibial torsion, you do a tibial derotation, osteotomy. Um If uh if all the biomechanics is OK, then a medial patella femoral ligament reconstruction would be a sensible thing and I use a hamstring graft and use a V shape, er um er formation. So two attachments on the medial side of the patella and one attachment on the center of rotation on the medial side of the femur. Um And um if you've got a really flat notch, uh so that the patella is always going to be dislocating, then that's when the trochlear plasty can be helpful. So, uh uh that's not something every hospital will do or should do. And it's best done by people that, that, that specialize in it, but you can actually recreate the v of the distal femur on the front of the, of the femoral notch to hopefully make the patella more stable, but we do have to be careful about it because they don't do anything to recreate the shape of the patella to make it match the notch. So giving a nice v is great. But if you've got a funny shaped patella that's been used to being on a dome and then you suddenly create the trochlea at the front of the knee. You do get an incongruent patella, femoral joint. And because you only do this surgery, once people have closed their growth plates, otherwise you damage the distal femoral growth plate. You do have this problem where you may get anterior knee pain because the patella doesn't fit the new notch you've made. So that can be a potential concern. So now we're going to talk about osteochondral injury. This is a cause of anterior knee pain. It can follow patella dislocation. So the patella bangs on the lateral femoral condyle as it dislocates. And that can take off a chunk of the, of the cartilage under the patella or it might be a direct blow from the front. In fact, on Monday this week, uh I opened up a 13 year old's knee and put the um cartilage back on the front of her distal femur, which she knocked off when she dislocated her patella playing netball. Um So sometimes you get a chunk of cartilage and bone which is an osteochondral injury. Sometimes you just get a chunk of cartilage. This girl, it was just cartilage. Um in adults, these things don't repair very well, but if you're still growing, you can put on a, you know, three by one centimeter piece of cartilage with no bone on it. So long as you refresh the, the the surface underneath, so you get nice healthy cancellous bone, you can fix that back on and uh the majority of times it, it will heal back on and you can rescue a joint in a way that you can't do in a, in an adult. It's really useful when you've had uh any kind of anterior knee pain after an injury, whether you had a dislocation to always get a skyline radiograph. Um and you obviously get the equivalent of a skyline view when you do an MRI, but that helps you to spot osteochondral injuries and also spot the shape of the notch as well. If you have an osteochondral injury on your MRI, um that shows the cartilage is intact, but the bone underneath is thick and the bone has died, then you can drill through the bone without damaging the cartilage. And you can do that under X ray guidance and that will stimulate the bone marrow cells to infiltrate the dead bit of bone under the joint surface and stimulate healing in the child. Um If you've got a cartilage flap, er you can heal that back on with smart nails. But if you've got a completely loose one, then you have to open it up, reattach everything, scrape the surface underneath and then you can reattach that with smart nails. So this is a osteochondral injury that you can see on the lateral femoral condyle. The MRI showed the cartilage was intact over it. And so uh the way to treat that is to take them to theater under X ray guidance. To put past a 2.5 millimeter drill, you can pass through the epiphysis. So you don't damage the growth plate and you can poke up and down and mush up the bone that it forms a sort of sclerotic layer at the base of the dead bone. And that encourages is um nice marrow cells to come in here, heal over that area and then put them on in a knee brace and some crutches. And then that will generally heal over over the next few months. If you've got a loss of a piece of cartilage with or without bone on the underside of the patella, then that's really difficult to do arthroscopically. And what you have to do is open up the medial side of the knee, flip the patella over, then you freshen up the bed underneath, you replace the area of cartilage. Uh You may need to trim it to be the right side if it's been out of place for a while because the cartilage fragments grow in the knee, if they've been out for a few months and then you have to trim it to be the right size again. Then you can hold it with these smart nails that you can see down here, these are bioresorbable. So you find that after a year or two they're completely gone. And so that's much better than, than using metal screws. And we're gonna finish up by talking about medial plica impingement. So it's a fold of synovium that can, that, that sits on the medial side of the patellofemoral joint and it can sometimes be pinched if you have a very long one like this, but it's normal to have a plica. So you shouldn't just see it and think, oh, that's the cause of your pain. So the important thing is finger test, ask them to point where it hurts. And if they point specifically to the medial side of the patellofemoral joint and say most of the time my knee is fine, but sometimes I get a really sharp pain just here, then that would fit with a medial plica. Secondly, if you see edema on the stir sequences of your MRI in the plica, then you know, it's getting pinched and you know, surgery is going to be a good idea. But if you see a plica, that's not that big. If it's not got any edema in it and their symptoms are more vague, they point in that U shape under the patellofemoral joint, don't take them to the theater to divide the plica. It's a waste of your time. It's a waste of their time. It's a waste of theater time, it's not gonna be the cause of their symptoms. Um It keeps a lot of people in private practice money, but it's not ethical. Ok. So hopefully now you guys are all really good at understanding anterior knee pathology. You know how to use the finger test to differentiate, sending Laa New Hansen Osgood Slaters, patella, maltracking er fat pad pain on either side of the patella because people can point specifically with their finger and tell you what the cause is. So you don't need MRI scans if they've already told you the cause. So I often find, you know, if I think I've got an osteochondral injury and I'm taking them to theater, you know, you obviously want to get an MRI but for making a diagnosis in the adolescent knee, you can often do it just by them talking to you about their symptoms and their history and pointing to where the pain is. Um I, when I don't do MRI scans and the registrar sees them next time and gets a scan just to check in the last decade, I've never been wrong. So in other words, the scans always shown what I thought the problem was based on the examination. So if you use the finger test and listen to the patient, it's a pretty reliable part of the body for getting the diagnosis right, without needing scans. And compared with adults, we need far fewer scopes in the adolescent knee, far more MRI F FF sorry, far fewer scopes, far fewer MRI S but a lot more physiotherapy and a lot more of correction of biomechanics with osteotomies than you often find in the adult knee practice because the teenage years are when Children tend to present with pain from having crazy legs. And that's the best time to realign their biomechanics so that you can get their symptoms better. So I hope you've got some questions. Um, and I hope the pictures and images were helpful for you. Thank you, Miss Mitchell. Any questions on the chat? Uh None so far. Um I guess I'll start off with asking about the, the surgical treatment for a bladder if you, is that something that you'd be able to enlighten us or we would have to kill you? Yes, we stabilize the tibial tuberosity. But what I don't want to do is tell everyone about the operation and find that other people then go and give it a go and they might find it worked or might find it doesn't work because they don't know the way we do it. They don't know how the technique that we use that optimizes the chances that it will be successful and minimize the chances of complications or side effects from the screw because there are different ways you can stabilize the tibial tuberosity. Well, and what you don't want is a proud screw that sticks out and you don't want to cause any extra symptoms. And so once we've got our full follow up of all the patients that we need with skeletal maturity, then we'll know whether it causes any alteration to grow. And we'll know in what proportion it improves their symptoms and in what proportion it cures their symptoms and so on, then we're in a better position to present it to everybody. Um, so don't go out and do it yourselves just from hearing it from me because you won't know how we do it. So it's, it's um but that, that's the thing. If you stabilize the tibial tuberosity, it stops the patella tendon, pulling on the tuberosity, helps the inflammation to settle down. And then that's how it works. And so far it's been really effective and we've done over 40 now. We, well, I've got 20 at my end. So I'm not sure how many you've got at your end, some other. Yeah, great. Thank you very much. Um So far, no questions, but we've got some visor towards the end. So if um if you're staying on with us, then there there is a vi session at 440. Otherwise, thank you very much, Mister Mitchell, right? Mister Lo um guide me through um screen share.