Dr. Kristin Livingston presents "Rotational and Angular Limb Differences – Approach to Children with In-toeing/ Out-toeing/ Bowlegs/ Knocked Knees" at the UCSF Pediatric Musculoskeletal and Sports Medicine Conference 2023 in Berkeley, CA.
Without further delay. Uh I'd like to uh introduce our first speaker uh this morning. Um, and that would be uh Doctor Kristen Livingston, uh Doctor Livingston, um, is one of our uh pediatric orthopedic surgeons here at U CS F be Childrens Hospital. She practices mainly at the Mission Bay Campus. Uh She went to U CS F for medical school, um orthopedic surgery, uh residency at Harvard and then pediatric Fellowship at Boston Children's Hospital, um at U CS F. She serves at, as the Director of Education for our uh division of pediatric orthopedics. She also serves as the Director of physician experience for our Department of orthopedics. Um Her clinical interests include uh pediatric orthopedic trauma and limb deformity. And today she'll talk to us about Toral angular development of the lower extremities and Children. Thank you doctor. Thank you so much, Selena. Um It's really great to be here talking with you all today. Uh We're gonna start the morning off with a bang, everybody's favorite topic of in towing and other things as well. Um I have no disclosures. So, um our goal today is really to sort of understand what is normal developmental and what is pathologic in terms of torsional and an angular development of Children. So we're going to review the history and physical exam for rotational and torsional alignment um and show some examples of what's normal and what is deformity. And then um we'll also review the history and physical exam for angular and coronal plane alignment issues and also go through some examples of what's normal and what's not. Um So first to start out with torsion, right. So this refers to twisting, abnormal or twisting in the axial plane. Um So mostly this shows up as either in towing or out towing. And we get lots of consults for in towing especially. So there's quite a journey of torsional development from a fetus in utero to a skeletally mature adolescent. Um in utero, the uh femur will be twisted anteriorly or internally. There is uh the hip joint sits externally rotated, the tibia is internally rotated, internally twisted and then there's variable position of the foot. So over the 1st 10 years of life, a child is going to sort of untwist. This is this magical process of childhood skeletal development that happens on its own. So the tibia will externally rotate by about 15 degrees, the femur will untwist by about 25 degrees. So the first decade is really a moving target. Um but most of the time when there are concerns about this, it's a concern of in towing. And while we see it as a foot issue, it can really come from any level in the lower extremities. So, very commonly from the hip, from femoral antigen or from the tibia, from tibial torsion or from the actual foot, which would be metasis AUC. So we'll go through all of those different, um, uh, different problems. Um, so first when we're talking to the patient, we wanna know obviously how old they are. That's the most important thing in pediatric orthopedics all the time. Um Because the physiologic stage very much drives uh where they, where they are in this untwisting process. Um And then how long the problem has been present? This is often something where parents will say it's been present forever since they started walking. So you want to get a sense of this is getting worse, they're getting better. Um And is it causing functional problems? So keep in mind, tripping is very common for a toddler. We get lots and lots of consults for in towing causing tripping and a two year old. And you're like, that's actually pretty normal. Um So tripping is normal when they're little, but it's not always normal for an eight year old. So those are ones you want to pay more attention to. Um And then symmetry, most of these issues are symmetric asymmetry raises a red flag and um birth history, you know, is their normal growth um normal growth curve and uh and family history because obviously the apple doesn't far fall, fall, far from the tree. Um So when we look at them, you know, just getting a general sense of overall height and weight. Are there any dysmorphism? Is there possibly a skeletal dyslexia here or a syndrome? Um, we want to look, you know, examine their spine, um, look at their limb lengths. Um, and that's usually an exam we do when they're standing and then looking for neutral, lower extremity alignment. When it, this is just an issue of torsion, their legs should be straight. So if you pull, if you have them stand straight up the knees and ankles should be touching. Um, and, uh, uh, torsion doesn't usually carry any coronal plane alignment issues. So, um, we want to watch their gate and please don't judge their gate before they start walking. Um, you know, little kids who don't quite walk yet, it's hard to, um, you know, a lot of people worry that, oh, they put their feet outwards or, or inwards. Um, and it doesn't really become relevant until they're actually walking. So the toddler gate is obviously very different, right? They have a very wide based externally rotated gate, but it becomes more of an established he toe gate by the time they're around three and then really doesn't fully mature until they're about seven. You want to pay attention to the inward or outward foot progression, right? So we look at the angle that the foot makes relative to the line of progression. Um And that's what sort of shows us the internal or external, um, or the in towing or out towing. Um, and then also look at their, the position of their knee and gate. So sometimes the knee follows the foot, sometimes not. Um, and then obviously looking at their overall coordination, but this sort of, um, uh, just demonstrates why you want to look at both the knee and the foot in gate. Um Sometimes you could have the feet pointing inwards, but the knee is pointing straight ahead or you could have the feet pointing straight ahead and the knees pointing outwards or both the knees and the feet going in together. So just keep an eye on the foot progression, but also where that knee is landing in gate. So when we assess their rotational profile, this is really how we figure out where the towing is coming from. Um You begin by assessing their gait, obviously the overall attitude of the way that the limb is going. Um And then you want to assess their prone hip rotation to determine whether whether this is due to femoral torsion. Um You're gonna assess their prone tibial torsion, looking at the thigh foot angle and then also looking at the foot to see whether or not the foot is curved. So the femoral torsion um is assessed by putting a child prone on a table, um, and then bringing the feet out like this, which is internal rotation of the hip, right? And bringing the feet together like this, which is external rotation of the hip and in a child with a lot of internal femoral torsion, those feet are gonna be able to come way apart. Um And uh you're really paying attention to see, is this very unbalanced? Do they have tons and tons of internal rotation and less external rotation or vice versa? So this can show you if, if, if a child has more femoral anti version or retroversion, and then these graphs sort of show you that this is a very changing, this is a changing process over time. So the um the hips will have a lot more internal rotation early on in life and more external rotation later on in life. And then if you, so this is just a nice picture of really what the femoral anti version is. It's the rotational angle at which the neck of the femur attaches to the shaft of the femur, right. So this is a normal femur on the on the left um which shows you that the thermal neck is just a little bit rotated forward, right? Normally about 15 degrees in an adult. But in a in a child, that anti version can be huge, like even sometimes 50 degrees um angled forward. And so that's what this twist of the femur looks like. And then this is why femoral introversion causes in towing, right? Because if you have a normal hip. You see how the femoral head sits nicely in that socket with the knee and foot pointing straight ahead. But if you have a significantly antiverted femur, then that's not a comfortable position for walking, right. When they put their foot down and bear weight, they're gonna want to rotate the whole limb internally to get that hip seated more squarely inside the hip socket. So it's really an issue of turning your leg like this when you put your foot down because that brings the head of the femur more deeply inside the hip socket. Um And then this is just a graph that shows you how the femoral anteversion decreases over the first decade. So it's really this like long, slow process. Um And we often, we often see these in to right around age five and we have to say just be patient, it's gonna get better. Um So this is femoral anti version is usually the cause of in to in school age Children. Um It should be symmetric. Uh Children may trip and fall more than average because their feet are getting in the way of each other. Um And then everybody wonders is w setting a problem and it's really not. There's nothing that's been shown that w sitting prolongs or perpetuates family inter version, it's just the way that they're comfortable. Um And this may be in combination with other causes of towing. Um It often can worsen for the first few years and then typically resolves around age 8 to 10. Um, again, it can be genetic. Um, there's no role for bracing here and really, there's almost never a role for surgery. Uh, technically you can do a femoral osteotomy, um, to, uh, cut and rotate the femur if this is really a terrible, functionally limiting problem. But that almost never happens. I think I've operated on Two and Towers in eight years. Um So it's not something we typically do when we say, well, we can cut your child's femur and rotate it. They're like, ok, bye, bye. Um So just important notes about the referral, we almost never operate on femoral anteversion. Physical therapy is not going to change the rotation. This is a structural issue, bracing and shoe inserts are also not going to change their in towing. Um And then in terms of like when to address this, you will never miss the boat. This is not amenable to guided growth techniques. Um And this is something that we would never operate on until at least age 10. So that's femoral anteversion right now. Just a quick word on tibial torsion. So this on exam, you're gonna examine by the thigh foot angle. So again, you place the child prone, you bend up their knee and you look at the angle that the foot makes relative to the thigh. And that's gonna show you that the tibia is either twisted internally or externally and then again, it's a changing process um through growth, the uh it starts out relatively internally rotated and the tibia will untwist over time and end up relatively externally rotated. Um And internal tibial Turin is typically the cause of in toing and toddlers. Um It's mostly symmetric, it's thought to be due to inter um intrauterine positioning. Um tripping and falling is very common, right? You get your toes tripping over each other. but again, no amount of tripping as a toddler is abnormal, right? Toddlers fall all the time. That's what they do. They're very good at it. Um And uh and so again, this can be in combination with femoral an aversion, for example, but typically the tibial torsion will improve slowly by around age 3 to 4. Um And then in turn, you know, notes about referrals. So we almost never operate on tibial torsion in healthy kids, spina bifida, et cetera, different story. But in healthy kids, we almost never have to manage this. Um Physical therapy is not gonna change the rotation. You know, it said sometimes it can help with clumsiness, but it's not gonna change their alignment, bracing and shoe inserts are also not going to change the rotation. And again, you'll never miss the boat on addressing this. This is not amenable to guided growth, we can fix it any time, but we almost never do. Um And uh families are extremely unlikely to want osteotomies even in severe cases So then the the other thing that can cause in towing of course, is metered. So this is the the curved foot where you have a curved lateral border, you also look at your heel bisector line here. So the hill bisector line normally goes through the 3rd, 2nd between the 2nd and 3rd toes. Um but it's more lateral than that. Me and you have to differentiate this obviously from a club foot, right? But a club foot has all the other deformities as well. The hindfoot, varus the, the aqui um and so in meta, the rest of the foot is normal, it's just curved uh when you look at it from the top down and um and uh the ideology is um probably intrauterine molding. Um and then it often has this trapezoidal shape of the medial form. Um It's pretty common happens about one in 1000 births. Um But more common if a sibling is affected, there's a higher rate in males or twin births or preterm neonates. Um And there is a possible correlation with D DH. So we do recommend screening kids with metasis with a um with a hip ultrasound just to make sure they don't have hip dysplasia. Um and this is the usual cause of in towing in the early days. Um And this can also be caused by a hyperactivity of the abductor lysis muscle, um which just makes that, that big toe sort of really reach over and um and curve inwards. So in terms of um how we treat this, it's really based on the flexibility. Um So in a flexible foot, which corrects beyond neutral, we're just gonna observe that usually gets better if there's a partially flexible foot, meaning that it only corrects just to neutral but not beyond, we usually do some stretching and, and maybe some casting. Um and uh and then if it's rigid, then that's something we're gonna treat earlier with casting or, or some um spring loaded orthotics, but um just sort of busy slide. But the main point of this slide is to say that all the causes of in towing typically end up. Ok. So it's really rare that we need to treat in towers. Um And then I always like to remind parents that, you know, uh these, these are a few in towers being awesome, right? So Andre Agassi and Michael Jordan and John Elway are some examples of, of uh some high level in towers. And some people even think that in towing makes you run a little bit faster. Um external rotation and out towing um is really less common, but this can come either from the hip, external rotation, contracture of birth. Um The from external femoral torsion, um external tibial to or Pez Planovalgus, right? We don't see it as much um when they're, when they're a baby, they, they always have their, their legs are externally rotated, right? The kids put their feet down, um uh widely and externally rotated. And that's because um in utero, they develop this soft tissue contracture. So their hips, even though they're femoral, even though they have femoral antigen, the hips are externally rotated when they're little is the kind of common finding during infancy. Um So this external uh rotation contracture hides the normal increased femoral an aversion if that makes sense, but then it goes away. Um And then uh you can have external femoral torsion. So this is more common in older Children because this is when they walk out towed because their hip is externally rotated in gate. Um This is often hereditary. But keep in mind if this is acute, if this is a new problem or unilateral, we consider things like um like kelly per disease or especially a skiffy in an a in an adolescence. So pay attention to new out towing. Um You can also have out towing from external tibial torsion um where you have external rotation of the feet relative to the thighs. Um In severe cases, this can cause issues with gate efficient git inefficiency and difficulty running. Um And then sometimes you'll see out towing due to flat feet. So this is normal in young Children. Um, most toddlers do not have an arch, um We don't expect them to, they develop it over the first, you know, 678 years of life. Um and then uh flexible, painless flat feet are normal and do not need treatment. Um So that's a whole other topic. Um And then you can have these weird combination deformities of um of different uh axial alignments, right. So this is uh in this person, you can see that the femurs are rotated inwards and the feet are rotated outwards, right. So when the knees, when the feet are together, the knees are pointing in, when the knees are straight out, the feet are facing outwards. This combination deformity of femoral anteversion and external tibial torsion is called miserable mal alignment syndrome, which is kind of a shocking name, but it, but it often does cause some significant knee pain and um difficulties in gait. And so, um uh every once in a while, um this will need to be treated. We sort of this is how we assess the different rotational alignments on um axial imaging. And then in a, this is one that we actually may treat um because it does cause so much uh so many problems. So we would treat this with um acute rotation of the femur and a gradual rotation of the tibia. But that's obviously a big thing for a kid to go through. Um Oh yeah, knee pain. And to be honest, when, when miserable M alignment comes in, the main thing, parents are like they just walk differently, they just look weird, right? And because people can't quite get a handle on what's going on. It's an awkward gate, their knees are, are in, their feet are straight ahead. Um And so it's uh it's often like we can't quite put a finger on it, but they just look like they walk differently and then they also have knee pain because that's something that stresses the patella. Um OK. So that's torsion and then we'll go quickly through um some coronal plane alignment, right? So I wanna make sure everybody is clear that we think about axial issues differently than coronal plane issues, right? So this is when you're looking at somebody in the frontal plane, um and the way that their legs look to you um in that plane as opposed to torsion, which is the ax plane twisting issue, right? So this presents as bow legs and none. Um And again, when we're talking to the patient, you know, age is extremely important because we'll talk about the uh moving goalpost of Coronal plan alignment in childhood. And we want to know if there's progression, if there's change. Is this getting better? Is this getting worse? Is it causing functional problems? Um This is one that might actually cause pain. Um And is it symmetric or most of the time we think of these as symmetric issues? Certainly, we don't wanna think about metabolic and dietary issues because this is something where rickets could come into play, um or other metabolic bone diseases. And then, um, we wanna look at their, their growth curve, um because skeletal dysplasia is often also something that can cause a coronal plane abnormality, um, and family history. So, um, look, looking at their physical exams and most importantly, we look at their limb alignment, right. And that can be standing or so pine, usually both with their knees extended, the knee caps pointing straight up. Um, a neutral alignment would be when the knees and ankles both touch. Um, genu would be, or bow legs is when there's, um, when your ankles are touching, but there's space between your knees and then genu gum or knock knees is when your knees are touching and there's space between your ankles. So my sort of rule of thumb with what's an important amount of virus or vagus when you can put your, your hands straight between their knees or your hands straight between their ankles. Um, that's a clinically important amount. Um, and then angular development just like to, I know we talked about that changes a lot over the first decade. Angular development also changes a lot. Um, as well. So little babies, they are quite bowlegged, right? Little 18 month olds, especially, um, they're when they're born. Ok. And then they sort of cross around age two, they neutralize and then go to Valgus, um, which peaks around age 4 to 5 and then they hit their normal, um, uh, mature alignment by around age six or seven. So, um, you can see this sort of curve again, it's very much a, a changing, um, picture throughout growth. And this is again, just the picture of the little like, you know, 12 to 88, 12 to 18 month old baby with, um, little toddler with both legs. And then usually the two year old is gonna have pretty neutral alignment. The four year old is gonna look very knock. Um, and then the six or seven year old should really look nice and straight. So, um this is the, we, we watch this happen, we expect resolution in most healthy kids. Um And we wouldn't intervene very early for this because again, we expect it to resolve on its own. Um This is how we assess it radiographically. Um So we look at the mechanical axis and the mechanical axis is. So, first of all, we take a, an x-ray from hips to ankles with a child standing with their knees straight and the kneecaps pointed straight ahead. And then we look at the line that we draw between the center of the femoral head, which is the center of the hip joint and the center of the ankle. Um And that line is called the mechanical axis and it should go straight through the center of the knees. So this is how we assess this radiographically if it misses the middle of the knee. Um That's what we call mechanical axis deviation. And we would, you know, actually give like a, you know, two centimeter mechanical axis deviation Um And so, uh, and you know, it's often, sometimes kids can look a little knock or a little bow legged, but, you know, their soft tissues can play tricks with us every once in a while. So this is sort of the real objective data about what their skeletal alignment is. Obviously, those knees are designed to take the force right through the center. And so if you've got the, your mechanical access, the line of force very laterally or immediately deviated, that's not necessarily gonna be healthy for your knees in the long term. So those are the things that can drive like knee arthritis later in life, which is why we care. Um And uh this is another just very busy slide of how we assess these things, but these are all the angles that we draw, um to really determine exactly where the deformity is coming from in the lower extremity. Um So most of the time, uh this is physiologic and um especially in little toddlers. So, physiologic geri is the most common cause of bow legs and toddlers. Um We see it more in early walkers. Um It's very commonly paired with internal tibial torsion as well. So you get these little bow with a twist. Um And this tends to resolve by about two years, but virus over age two is abnormal. Um But I will say we always get the consults at about 18 months old and just wait a little bit longer. Um, because that's gonna be when things resolve on their own. And, um, uh, so this virus again should, um, should resolve by age two. It's abnormal after a child is two. Um, and then this is just called the cover up test. This is sort of how legs can play tricks on you, especially when there's a little bit of internal tibial torsion if you cover the bottom of the leg, um, with, uh with your hand, you can see that that knee is actually a neutral alignment even if it looks bow. Um Yeah, so then um but pathologic is it, it shows up um and it uh it can occur from a variety of problems. So we see disease, right? Um which is a very common um issue and that's something we want to pick up early. Um We can see uh we can see geva in rickets um and things like renal osteodystrophy. Um But loads of things, skeletal dysplasia is like achondroplasia and osteogenesis imperfecta. Um And then certainly other less common issues like um Osteomyelitis can lead to damage or um or trauma can do the same thing and lead to um growth alignment issues, um or even um things like radiation. So, but just a word on disease. So this is a disease of the medial proximal tibi of physis. Um It can happen either as early onset or late onset. Um more common in African American population, obese patients and early walkers tends to be bilateral and infantile cases. They may look normal at birth, but sort of develop these bow legs over the first couple of years. Um And it's a we, we really, we mostly see those bow legs, but it's a combination deformity of various provitamin internal rotation. Um And then the late onset cases are just uh you know, they tend to present more in adolescence. Um and it's more commonly unilateral. we assess this on uh radiographs again by um drawing some angles. This one is the meta dia angle and we look at the alignment of the growth plate relatives to the shaft of the tibia. Um And in this case, we can take this x-ray around age two or three and have a decent sense of whether this is going to be something that resolves on its own or something that progresses to blonds disease. So, a um an MD A of over 16 degrees has a very high rate of progression to blonds disease. Um But this is what it looks like around age 3 to 4 in a case that really, really desperately needs to be treated. Um And in severe cases, uh you know, we classically have done osteotomies around age three um to uh to change this alignment and sort of save this. Um though now, more and more, we're, we're trying to do these with um with guided growth um and avoid the big osteotomies, but these kids can end up having a lot of surgery over their lives, um to, uh, to manage a very complex, um, multiplanar deformity. Um, and this is just another example of, of disease. We classically correct these with, um, with uh gradual correction with a frame. Ok. But in the cases where kids are still growing, um, and we have an open, we have the opportunity to do a guided growth technique and then in terms of the referrals. So, you know, we recommend, um, referring bow legs at when they are over two. Um, because if it really is a bounce disease or something like that, we want to know about this early before that, before that really becomes, um, irreversibly damaged. And, uh, um, so oftentimes, you know, around age two, if there's a significantly impacted kid, we're gonna, um, maybe even do, uh, bracing for them, um, and possibly surgery as early as 3 to 4, um, to avoid a really, um, disease and then, um, uh, Valgum. So that's the, the opposite, the opposite way. The, the none. Um, and this is pretty common and usually normal. Um, this is normal in a child of less than seven. Um, there's no role for bracing here. It's ineffective and unnecessary. We just, um, expect this to get better on its own. Um, and even, you know, again, being able to put your hand through the ankles of a, of a five year old, that's totally normal. Um, but we monitor that distance over time. So we'll actually measure, you know, the number of fingers that you can stick between their ankles and see that those that, that's getting smaller and smaller as they grow. Um But then certainly there are lots of examples of pathologic Jenny Valgum. Um So this uh even just in idiopathic cases, they, they may not resolve by age seven. Um this move is more common in obese kids or um kids with ligamentous laxity. Um Some kids will have hypoplasia, ave lateral femoral con um and uh it can happen in post traumatic cases as well where you have an injury to the. Um So this this again is just normal idiopathic healthy kid that didn't resolve. Um But then this would be an example of traumatic here. This is called a coin's fracture. And while it's typically non displaced early on, we do have to watch this one um because it can lead to a growth um abnormality where the um leg grows into valgus, um usually gets better but still something that bears monitoring. Um and then uh but also a growth arrest from a facial fracture can um lead or from infection as well, can lead to problems with growth and Malign. Um and then of course, metabolic bone disease classically um can cause a severe genu gum. Um And so these would be things like either rickets or renal osteodystrophy. Um And this is an example of an x-ray. Um with the findings of rickets, right? Those growth plates are um widened, abnormal frayed. There's vil fraying and cupping. This is what we see in cases of rickets. Um, and then other causes would be things like, um, you know, neuromuscular disease, um, or dysplasias, right? This is a case of um, multiple pile dysplasia. Uh, and these are, these are tough ones to manage. But, um, but all kinds of things can cause ge vagum. The important thing is that we do, you know, address and treat this. Um, this is not the very benign situation of in towing. Um, it's, this actually can lead to, um, problems later on. Right. We worry about that imbalance of, um, the forces going through the knee and we don't want that to lead to problems later in life. Um, trust, treating the metabolic and reversible causes can actually lead to spontaneous improvement. So, when we have kids who show up with rickets and severe malalignment, once they start getting on, uh, medical management, they can actually, um, straighten out on their own with surgery as a, as a backup option. Um, but orthotics and shoe modifications are not gonna be helpful here. Um, and, uh, and once they do hit that age of around, you know, 10 and there's still, um, knock need, then, uh, we would recommend doing guided growth for a lot of those kids if it's a significant amount, um, guided growth, patients are extremely satisfied. Um, this is like one of the smallest and easiest surgeries that we do and just the most satisfied patients, they love their straight legs, um, at the end. And, uh, but we just put these little, um, these little, uh, plates and screws across the growth plate, let them sort of cook and grow for a little while. And then all of a sudden they have straight legs and we take them out. Um, so that's a satisfying correction to uh to give them a neutral mechanical access. Um So that those knees are healthy for the rest of their lives. And, um, and then, but when they're done growing, we don't have that option of guided growth anymore. And so in that case, we might um turn to a femoral osteotomy to acutely realign the bone and that's easy enough to do. It just is a, is a bit harder on the patient because of the non weight bearing and everything afterwards. Um So, uh in terms of referrals for noc knees, um, healthy kids with mild nock knees should be referred around age 8 to 10, um for discussion of surgical options because if you're still knock need around age 10, it may not go away. Um But then certainly with the kids that are severely affected or, you know, where it looks like a pathologic case, um Then we would want to see those kids early to address any treatable causes and that is all I have. So I'm happy to take questions if there are any. Oh, questions at the end. Never mind. Ok, bye everybody.