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Dr. Heather Kong discusses leg length discrepancies in children, symptoms to look out for, and medical care provided at Shriners Children's Portland.

Leg Length Discrepancies in Children

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Melanie Cole, MS (Host): Welcome to Healing Heroes PDX, the podcast series from the specialists at Shriners Hospitals for Children in Portland. I'm Melanie Cole. Today we’re discussing leg length discrepancies in children. Joining me is Dr. Heather Kong. She’s a pediatric orthopedic surgeon at Shriners Hospital for Children in Portland. Dr. Kong, it’s a pleasure to have you join us today. So tell us what types of leg length discrepancies can occur and how common is this?

Heather Kong, M.D. (Guest): So leg length discrepancies can occur for a lot of different reasons. Sometimes they are true differences in the lengths of the bones in the legs. This can sometimes be something kids are born with without any real underlying reason or cause for it. Sometimes it can be related to another condition like a skeletal dysplasia or a genetic syndrome. Sometimes it can occur after an injury or an infection that damages the growth plates in the legs. There are also a few conditions that can look like a leg length discrepancy. For example, a hip dislocation in an infant or tightness in a joint that doesn’t allow it to fully extend. So even though the lengths of the bones are not different, it can look like a leg length difference. Sometimes a leg length difference is noticeable as a newborn or a young child or depending on the cause sometimes it doesn’t show up until the child is older. Leg length discrepancies are very common. There are plenty of people who don’t even know they have one. Studies have shown that anywhere between 30 and 75% of the population may have a leg length difference up to about half an inch with no symptoms at all. Once a leg length difference is more than about one inch or two centimeters, that’s where studies have shown that it may effect the way you walk or how you compensate for it. There are also potential concerns for leg length differences causing hip problems or back pain in the future, but the data on this is not as clear. So in general we as orthopedic surgeons tend to recommend treatment for a leg length difference when it’s over one inch or two centimeters.

Host: So do you prominently see younger children for these conditions, or does it vary? Are there any symptoms that you’d like parents to look out for if it’s not something that they were born with?

Dr. Kong: The age at which it becomes apparent does vary quite a bit. Sometimes we see them in toddlers or younger kids. Sometimes it’s not until teenage years. What parents might notice sometimes is that their child looks like they're limping a little bit. So maybe their pelvis is tilted a bit when they walk, maybe their trunk leans a little bit to one side. Sometimes parents will say they walk funny, and they just want to make sure that it’s not something to worry about. If the leg length is a bit bigger and a bit more noticeable, sometimes kids may walk up on their toes on the one side to try and keep their legs even. Sometimes they keep their knee bent on one side to try and keep their legs even. So those are things that parents can look out for. Another quick test might be when the kid is lying down with their legs out straight. Parents can get a quick idea of whether or not their legs look like they're equal in length, but that’s not always a super reliable method. The most accurate way to measure a leg length difference would be to get an x-ray. The x-ray would tell us the length of each bone and where the difference might be coming from, plus it gives us some clues as to what might be causing a leg length difference. For example if there's a problem with any of the joints or any of the growth plates.

Host: Well then are there other side effects that kids could experience as they grow? Why is it so important to catch these conditions early?

Dr. Kong: For a mild difference there probably is not a lot of other complications or side effects either in childhood or adulthood. For larger differences, there can be things that we would want the kids to do as they're growing in order to prevent more problems. So for example, if a child is always walking up on his toes that could lead to heel cord or Achilles tendon tightness. So we would want to try to avoid that. Similarly if a child is always walking around with one knee bent, that knee might start to get tight in that position. So it would be important to maintain good stretching and range of motion of all of their joints. Some kids need a brace or a cast to help with that. We do provide shoe lifts a lot of times for kids that have a bigger difference.

Host: Then tell us about some of the types of care. You just mentioned a few. Tell us some of the others. Expand on this a little. Some non-invasive treatment options, and then what type of surgical interventions might a family expect?

Dr. Kong: So the main decision point is deciding whether or not the discrepancy is going to be large enough that we should equalize the leg lengths. This isn’t something you can always tell when the kids are very young. Sometimes we have to track for a while how quickly the difference is changing and get an estimate of what we think it’s going to be when they're at skeletal maturity or when they're done growing. So if a very young child has only a one centimeter discrepancy—less than half an inch—we don’t always know right away if this difference is going to increase over time or if it’s always just going to stay at one centimeter. So we tend to get an x-ray every few years or so maybe just to see how things are tracking. The more data points we have, the more accurate we can be with our predictions. I think sometimes families need to know that this treatment process can be more of a marathon rather than a sprint. The goal is to make sure, again, that when the child reaches maturity they have equal leg lengths. So there might be longer periods of watching and waiting in between. Once we decide that surgery is the right decision, there are several different options for treatment depending on how big the difference is and how old the patient is. If the child still has several years of growth remaining—for example if they're maybe 10 years old or less—that gives us the most options for the different types of surgeries that we can potentially do. Once kids are closer to being done growing—maybe within one year or two years of being done—there are still some options but perhaps not as many.

In general terms, the surgery options involve either shortening the longer leg or lengthening the short leg. The shortening procedures tend to have a faster recovery time and fewer complications, but they do take away from the overall height potential of the child. On the other hand, lengthening surgeries tend to be a bit more complicated, a bit more unpredictable, and the recovery process takes longer often times six months even up to a year. However, that technology is continuing to evolve and improve over time. For example, we now have growing rods that we can implant into the bone and then lengthen with an external magnet to slowly equalize the leg length.

Host: Isn’t that amazing the technology today? Dr. Kong so what advice do you have for parents who have children with this condition? Tell us a little bit about some of the psychosocial and emotional side effects that can go along with this type of discrepancy.

Dr. Kong: So I think that for parents who just hear maybe from their pediatrician or from a physical therapist or something that their kid has a leg length difference I think that the first thing to know would be not to be alarmed because that can mean a lot of things and a lot of different scenarios. I think at that point the most important thing would be to get more information. So if they were to have an appointment with us here at Shriners, they'd be seen by one of our orthopedic surgeons who will take a throughout history and exam, get some x-rays, and get some more information that way. We are a specialized pediatric orthopedic center. We probably see more of these kids with this issue than any other in the region. We also have, at Shriners, a special x-ray machine called an EOS machine, and that allows us to take full length leg x-rays with much lower doses of radiation than regular x-rays. That’s a huge advantage for our patients, especially if they're needing multiple x-rays throughout their childhood. So once we kind of know what we’re dealing with, the next step would be that they're in good hands with whatever that treatment process is going to be. Especially for the kids that are going through the lengthening surgeries—which, again, are the most complicated of all the treatment options—it can be pretty overwhelming because it’s a lot of doctor’s visits, a lot of physical therapy, a long recovery time. We do have a pediatric psychologist on our staff which helps our patients cope with either the surgery itself, the recovery time afterwards, or any other needs whether it’s related to surgery or not. Same with our child life specialists, our social workers, and our therapy staff.

Host: Well thank you for telling us about the multidisciplinary team that provides care to these patients. How is the patient experience different at the Portland Shriners hospital?

Dr. Kong: As I said before, sometimes the information that we have at that first appointment is more of a jumping off point. It might be the type of situation where we really need to see how it develops over time. As I said, if the child needs any physical therapy to help with development milestones, with certain activities that they're having difficulty with, our physical and occupational therapists are right there in the same building with us. We can connect you to them right away. We also have our orthotics and prosthetics department in the same building. If a child needs a special brace, a special shoe lift, our orthotist are some of the most experienced in the area in dealing with those sorts of things as well as our psychology and child life department. In addition I’d like parents to know that we have really experienced and really dedicated staff in all departments including rehab, x-ray, nursing. Whether it’s related to a surgery or not, we care for patients with this condition often. We know how to guide them through it pretty well.

Host: Thank you so much Dr. Kong. What an interesting episode. Thank you for coming on and sharing your expertise with us today. For more information, you can call 503-221-3422 or you can always visit us online at for more information and to get connected with one of our providers. That wraps up this episode of Healing Heroes PDX with Shriners Hospitals for Children in Portland. Please remember to subscribe, rate, and review this podcast and all the other Shriners Hospitals for Children Portland podcasts. I'm Melanie Cole.

About The Speakers

Heather Kong, M.D.

Heather Kong, M.D., joined our medical staff following her pediatric orthopedic fellowship at St. Louis Children’s Hospital and Shriners Children's St. Louis. Dr. Kong received her undergraduate degree from the University of California, Berkeley. She then earned her medical degree from Washington University in St. Louis, followed by an orthopedic surgery residency at Rutgers University in Newark, New Jersey. She completed fellowship training in pediatric orthopedics at St. Louis Children’s Hospital and Shriners Children's St. Louis. During her training, she received awards in research and teaching. Dr. Kong’s publications have focused on pediatric orthopedic trauma and lower extremity deformity.

Learn more about Dr. Kong

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