What to know about hip dysplasia in children
Hip dysplasia is the most common cause of hip arthritis in women younger than 50 years of age, and most are born with it. In fact, 1 in 10 infants in the U.S. is born with hip instability. Pediatric orthopedic surgeon David Lazarus, MD, explains what parents need to know.
Dr. Rania Habib (Host): When we think of hip problems, our minds automatically drift to older Americans who need hip replacements. Hip dysplasia is the most common cause of hip arthritis in women younger than 50 years of age, but did you know that one in 10 infants in the U.S. is born with hip instability? This is Flourish. A podcast brought to you by Prisma Health.
I’m your host, Dr. Rania Habib. Today’s episode discusses hip dysplasia in infants and children and features, Dr. David Lazarus, a pediatric orthopedic surgeon for Prisma Health. Welcome, and thank you so much for joining us today to discuss this interesting topic.
David Lazarus, MD: Absolutely. Thank you for having me.
Host: When most people think of hip problems, osteoarthritis in older adults is usually what comes to mind. What is hip dysplasia and how common is it?
David Lazarus, MD: Yeah, so it’s a great point. So, hip dysplasia is something that we see a fair bit of in newborns and it’s a referral that we see quite often from our pediatricians. So, as you said, hip dysplasia is a common cause of adult hip problems in adults under 50, and so hip dysplasia is something that kids are born with and we call it developmental dysplasia of the hip.
The way to say that is DDH. But, dysplasia itself means abnormal growth or development, and so this is something that babies are born with and it’s a disorder of the hip joint.
David Lazarus, MD: And if you think about our hips, the hip is a ball and socket and the socket should cover the ball nicely and it should be very stable. So, during development, if once kids are born, if that hip is unstable and it covers a pretty wide spectrum of disease, but that is what DDH is. And so, on the more mild side, dysplasia can just be a hip that’s not well covered or a hip socket that’s not deep and the ball does not have a good position in the hip, but it can also be on the more severe side where that ball is just completely dislocated from the socket, and that’s a bigger problem. But fortunately we have a lot of good options on how we can treat babies as long as we can get them diagnosed appropriately, and sent to the appropriate doctors.
Host: That’s fantastic. That’s really good news for those children. What factors put a child at risk for hip dysplasia?
David Lazarus, MD: Yes, as you said, the incidence is not uncommon. We see it in about anywhere from one out of a hundred to a thousand live births. And so if you think who’s really at risk for this, the most common ones are either firstborn females, family with a positive family history. So somebody else in the family that has had hip dysplasia and breech babies is one of the big ones.
And so if you think about first time moms and when they’re pregnant, their uterus at that point is smaller than if they’re having their second or third child. And so the baby has less room and so there’s less room in the uterus for those hips to move. And with less room, that could be a problem. This is also where babies are frank breech, where the head is up and those hips are flexed almost completely against their body; that puts them at risk. And the other reason why females unfortunately are more at risk for hip dysplasia is that the hormones for mom are also circulating through the baby’s bloodstream as well, along with extra hormones produced by the baby as well. And so that creates some looseness in the ligaments around the hip joint.
And that unfortunately, can cause some laxity to those hips. And we talk about laxity. It’s just that hip being able to move a little bit. And in the future, if you have laxity as a teenager, or when you’re an adult, that can cause pain.
Host: It’s fascinating that females are at higher risk than males. Do you know what the difference in that number actually is?
David Lazarus, MD: Some of the evidence shows that it’s probably about one male for every six females.
Host: Oh wow.
David Lazarus, MD: So definitely, more problematic for our female population.
Host: What are some signs and symptoms a child or infant might exhibit that suggests hip dysplasia?
David Lazarus, MD: Yeah. So a good and bad thing. And so the good thing is that hip dysplasia for a baby or a young child, is very often asymptomatic. It is not painful at that time of a kid’s life. There’s not going to be any obvious thing, especially for a baby that you’re going to say, Hey, my kid has hip dysplasia.
And so it’s really important to, for one, to know of the risk factors. And, two, if the pediatrician or OB/GYN or even the family knows that getting the appropriate referral to a pediatric orthopedic surgeon. Some signs that we get a lot of referrals for which are not always super suggestive of hip dysplasia is a hip click or some clicking on the hip when you’re moving the hip around. We oftentimes we’ll get a referral for asymmetric thigh creases, so the creases on a baby’s chubby thighs are asymmetric. that’s not always totally suggestive of a problem. The other thing that may be more commonly seen in a little bit kids that are older, and I mean one, two or three years old, is that the leg lengths may be unequal.
So that can suggest that a hip may be out and be dysplastic, if you will. And always warrants a referral to either us or at least evaluated by the pediatrician to see if something needs to be done.
Host: What factors put a child at risk for hip dysplasia?
David Lazarus, MD: The risks that we talked about as far as being breech or family history, or firstborn females. It’s not something that the kids are going to develop after they were born. If they’re growing and they have normal hips at the beginning of their life, it’s, they’re usually going to continue to have normal hips.
There’s a different type of dysplasia that we do see in kids with neuromuscular disease who may be born with normal hips, but because of the abnormal problems they may have from their neuromuscular disease, they can develop dysplasia. But that is a little bit of a different beast than DDH itself.
Host: Okay, so when you see a child that you’re worried about hip dysplasia, how do you actually make that diagnosis? Are x-rays needed and is it safe for babies and children to actually get x-rays?
David Lazarus, MD: Yeah, absolutely. So if you look at all babies, if you look, examine every baby when they’re first born, that first or second week of life; babies usually still have some hormones from mom circulating in their blood, and that’s going to cause a little bit of laxity in their hips. There’s a lot of false positives if you were to go based off of the physical exam at one week of age for every baby.
So, when we examine them at three or four weeks. If there’s any concern on the exam, we actually first get an ultrasound in the first three to four months of life. The ultrasound is a very quick, painless and can be very accurately done by a skilled ultrasound technician or a physician.
And the reason we use ultrasound is one, we avoid radiation, but hips or the ball of the femur is actually still cartilage at that age, and so you can’t see it on an x-ray. So ultrasound gives us a live evaluation of that hip to see if one, is it in or out, and two, is it unstable? And three, just the size of the socket to tells us, does it need any treatment. And as far as an x-ray, we do use x-rays starting in about five or six months because that’s when the ball starts to actually ossify or turn to bone. It is safe. We don’t do many of them. It is a pretty small dose of radiation and it’s usually done about one to two times a year if we need to.
And it’s definitely worth doing as the alternative of untreated hip dysplasia can be a bigger problem in the future.
Host: It’s good to see that you guys are using ultrasound to avoid that radiation in children. Once you diagnose hip dysplasia, is surgery needed or how is it treated?
David Lazarus, MD: Yeah, so the big benefit of catching it early is that we have a lot of good treatment options and so, when we catch it early and a child is diagnosed as having hip dysplasia, we do treat them as long as it’s in the first six months, we treat them in a brace called a Pavlik harness. And although the pictures of a baby in a Pavlik harness look like it would be very uncomfortable; kids usually are very comfortable and the success rate of the harness is very high.
It’s usually worn for about two to three months. For the first 4-6 weeks, it’s pretty much full-time, almost, 23 and a half hours a day except for a quick bath. And we check during that time with ultrasound to make sure we are doing the right thing and that the hips are improving. That’s the benefit of being so young, is that the hip is still moldable and plastic, if you will, and that the speed at which that hip improves is pretty amazing. So, from a surgical standpoint if that brace fails, we go to a more rigid brace. And if that fails, we do proceed with something done in the operating room.
And that first step is not necessarily true surgery, but we’ll manually try to get that hip back in place. And this is, if the hip is dislocated. And so first step would be a closed reduction where we physically put that hip in, if it will go in, then they’re in a big cast for six to 12 weeks.
If that doesn’t work, we do proceed with surgery where we physically put the ball back in the socket, removing any obstacles that may be in the way. But the good thing is that as our medical community is much better at examining babies and diagnosing babies, our numbers of surgical intervention for DDH has definitely gone down over the years.
Host: Oh, that is so great to hear. Now, I know that some of these infants have really mild cases of hip dysplasia and may often go undetected until maybe they’re in that adolescent age. How does treatment differ for those kids in that adolescent age?
David Lazarus, MD: Yeah, so that a great point. It’s something that we are actually better at looking at diagnosing now currently than we were 20 years ago. It’s not going to become symptomatic until people that are older, and as you said, it is one of the most common causes of early joint replacement in young adults. But there is a chance that undiagnosed mild dysplasia can become painful. And so when teenagers, they may present to a physician and have hip pain, or they may have pain in their muscles around that hip, and sometimes they’ll do okay with physical therapy. But what happens is that hip isn’t sitting nicely in the socket. Or there may be some micro motion that causes symptoms and at that point there’s not great nonsurgical options. And if it’s diagnosed appropriately, we do have great surgical options that do have very good outcomes, to treat it. But you’re right, there is definitely mild dysplasia that still can go undiagnosed.
Host: Now what happens in, let’s say the infant or the younger child, if the dysplasia goes untreated?
David Lazarus, MD: Yeah, so if it totally goes untreated, it really depends on the severity of the initial dysplasia. So if it is dislocated that can be a big problem. Now, joint replacement is always an option, but it is something that you want to wait till as late as possible to undergo. And so if it goes untreated, in the US it’s not commonly seen where we get kids presenting with dislocations late.
Most of those are diagnosed early and we can still not always necessarily treat them with a harness, but we can treat them with surgery and get the hip in. But occasionally, if it goes untreated long enough, that hip may not be able to be put back in and be done safely for that kid. And so, you know, it definitely can open up another can of worms for that hip.
Host: Well, I’m glad that you guys are catching it early, and at least in the US we’re really seeing that lower rate of kids not being diagnosed early, which is fantastic.
David Lazarus, MD: Right.
Host: Can hip dysplasia be prevented?
David Lazarus, MD: It can’t be prevented. But with good pediatric care and appropriate baby well check visits, it can be diagnosed and knowing the risk factors, there’s always going to be kids that don’t have necessarily a positive exam, but don’t have risk factors. So there’s always going to be the babies that slip through.
But as long as we can catch all of the higher risk babies that get a good physical exam and get appropriately referred and get the appropriate imaging, we can hopefully catch most of them that that can be a problem to decrease the amount of kids that are going to need any further intervention more than the harness, et cetera.
Host: That’s fantastic. Well, we really thank you so much for your expertise, Dr. Lazarus. Are there any key take home points that you would like to leave with our listeners today?
David Lazarus, MD: Just, always know your risk factors and make sure we’re paying attention to the hips. Make sure you’re seeing your pediatricians appropriately. And one thing that we do encourage our pediatric doctors is that all breech babies should have an ultrasound even with the benign exam, because they are such high risk. And fortunately in 2023, we’re very good at treating hip dysplasia. So the more kids that we can prevent needing any surgical intervention, the better for everybody.
Host: Ah, I love that take home point. Prevention is definitely key. For more information and to listen to additional episodes of Flourish, please visit PrismaHealth.org/Flourish. This has been Flourish, a podcast brought to you by Prisma Health. I’m your host, Dr. Rania Habib. Stay well.
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