Pediatric Orthopedic Exams: The Hip

Wudbhav Sankar, MD, orthopedic surgeon at The Children's Hospital of Philadelphia, demonstrates how to properly perform a hip exam on a pediatric patient, including assessment for Legg-Calve-Perthes disease, slipped capital femoral epiphysis (SCFE), femoroacetabular impingement (FAI), femoral anteversion, developmental dysplasia of the hip (DDH), snapping hip syndrome or other psoas tendon problems, hip flexion contractures, iliotibial band tendonitis, greater trochanteric bursitis, and more.

Transcript

Pediatric Orthopedic Exams: The Hip

Woody Sankar, MD: Hi, I'm Woody Sankar. I'm an attending surgeon here at The Children's Hospital of Philadelphia. I'm also the Director of the Hip Program here at CHOP, as well as the Director for the Center for Young Adult Hip Preservation. 

Today, we're going to be going through a hip exam for pediatrics and adolescents. All right. So I think a really important part of the hip exam is watching a child walk. It's really an important dynamic assessment to try and understand exactly what the cause of the pathology is and what can be contributing. 

So I'll first start by having the child stand here on the floor, and if you could just walk for me over to the door. And as the child's walking, I'm looking at a couple of things. So I'm just going to have you walk back and forth a couple of times. So the first thing I'm looking at is their balance and their coordination. The next thing I'm looking at is what we call the “foot progression angle,” which is how the feet are pointed. Are they in-toeing; are they out-toeing? And the reason is, is that some pathologies at the hip can cause that. For example, slipped epiphysis can cause the child to out-toe. Keep going back and forth, if you don't mind. 

The next thing I'm looking at is the knee. So I'm looking at … Are the knees going in? We call that the “knee progression angle.” If the knees are going in, that means that there's some femoral anteversion in the hips, and that may be a contributor to the pathology that's going on. Similarly, if there's out-pointing of the knees that can be indicative of femoral retroversion. 

All right. So after we're done with the walking assessment, I usually have the child stand on one side at a time, and that's really to bring out abductor strength or abductor weakness looking for the so-called “Trendelenburg's sign.” So the first thing we do is have the child just stand on the left side and bring the right knee up like they're marching, having them hold the position. If the child is weak, they'll start to dip their pelvis and start to lose their balance. And so now I'll have the child stand on the right side, and bring it up. Perfect. And hold that position for a few seconds. Perfect. 

Now, if you get a completely normal exam, but you still are concerned that there may be some abductor weakness, it's helpful to kind of raise the bar a little bit and have the child do a single-leg squat. So let's do this. Go ahead. Yep, go ahead and squat down on one leg. Perfect. And come up. OK. And now try the right side. And again, if a child is collapsing — and he's doing a little bit of that — if a child is collapsing a little bit, then that can be concerning there's some abductor weakness which can be a sign of underlying hip pathology. 

So after we do the walking assessment and the standing assessment, the next important part of the exam is the range of motion assessment, which we do up on the table. So you can climb up on the table for me. All right. And usually I have the child lie on their back to start, with the affected hip to the outside, toward the examiner. So in this case I would be having him in this position if I was concentrating on the left hip. If you have a child that has bilateral hips problems, just take a second, have the kid spin around so that you could do both hips sequentially. 

All right. So the first thing we do, I usually start by just gently log-rolling the leg. And I'm seeing if there's any sensitivity or pain with that. This is a very mild maneuver, but if the child is very, very irritable, even this will cause pain, and that will give me a sense that I'm probably going to have to be a little bit more — a little more easy with the rest of the exam to not cause too much discomfort. 

If that goes OK, then I grab the leg. I ask the child to just completely relax. I bring the leg up into the flex position. The flex position for me is 90 degrees. OK. We'll asses how much the child can flex additionally beyond that, but we first start in a 90-degree position. I usually assess internal rotation in this position by moving the hip as such. And then I just measure by an angle between the body and an angle between the tibia, which in this case is roughly about 45 degrees. I then externally rotate in the same position, and you can see usually children have a little more external rotation that internal rotation. And this setting, it's about 60 degrees.

I then check flexion. So we stopped at 90 last time, but now I go a little bit more, and I try to get a sense of where the end point is, and it's sometimes a relatively subtle end point. You don't want a child that's kind of picking their butt off the table as you're jamming the hip up, but you will feel if you take your time and tell that there is a natural end point to the hip, which is somewhere around here. 

I think the internal rotation and external rotation in this position are very, very important exams, particularly the internal rotation. I find that's perhaps the best screening test for intra-articular hip problems. If a child loses internal rotation of the hip or has significant discomfort, it almost always means there's something going on inside the joint. Something like Perthes, or a slipped epiphysis, or a hip infection. External rotation tends to cause — or tends to come from — different problems such as psoas tendon issues or muscle pathology. So I find that internal rotation or loss of internal rotation of the hip is the best sensitive kind of screening test for an intra-articular hip problem. Then bring the hip into extension, and then check the same thing. So internal rotation now in the extended position. And in this sense, it's probably about 30 degrees. And then external rotation a little bit less, at about 20 degrees. 

The reason why I do the range of motion both in the flex position and the extended position is that you're looking for different things. In the flex position, the hip comes up next to the hip socket, and you're testing things like femoral acetabular impingement or irritability of the joint. In the extension you're really measuring rotational differences in the bone, so things like femoral eversion. 

So after we've looked at it in extension, we then abduct the leg, and it's really important to really put your hand on the pelvis and get a sense that the pelvis is not moving with you. So you can continue to abduct the leg and keep going, but really what you're doing is you're bringing the pelvis out. So you need to keep your hand here so that the pelvis stays still, and as soon as you see the pelvis start to move, that's when you stop, and that's when you know that he's hit the end of his range of motion. So, I do that on the affected hip. but I think it's also important to do that on the unaffected hip as well, and that's because it's really nice to have a control to compare your results to. And if the right side has no pain whatsoever and no symptoms, then that gives me a nice baseline of what presumably is what his left hip was before he had the issue. So, I then go over, I do the same thing on the right side. Again, bring it up into the flex position, check internal rotation in this position, check external rotation in this position, check flexion, check extension, and then internal rotation in the extended position, external rotation in the extended position, and then abduction again.

The next thing I do with the child still in the supine position is I check to make sure that there's no hip flexion contractures which would really only be present if there's a pretty significant hip problem. So if I was checking the left hip, I'd have the child hold onto their right leg. So go ahead and grab your thigh here. Perfect. And I put my hand here to make sure that the lumbar spine is nice and level, and then with the child holding their thigh up, I go ahead and take this leg and make sure that it comes all the way down to the exam table and it doesn't pop up in the air. If it stays popped up in the air, that means that there's a hip flexion contracture on the left hip here. OK. All right. 

So after we've checked for hip flexion contractures, we can then do a special test or two in this position to check some very specific problems. So the first would be to look for problems with psoas tendon, which is the major hip flexor. So to test the psoas tendon, I usually bring the hip into the flex position and externally rotate, abduct, and then internally rotate at the end. And what you may elicit is a popping sensation on behalf of the patient right in the groin, which is a sign that the tendon is actually popping over a bony prominence, and this is a very typical problem that we see in adolescent teenage girls, particularly dancers. So that would test psoas pathology. And if you were to elicit the pop, or the snap, or the pain, then that would clue me in that that's probably the source of the problem.

You can also do what's called an apprehension sign, which — with the leg in the extended position — you could externally rotate. If a child has subtle ligamentous laxity, they may feel some pain in the anterior capsule as they feel that their hip is trying to come out the front of the joint. So once we've done most of the things in the supine position, I have the child turn on their side. So turn on your side and face the wall. OK. And it's really important to keep them directly on their side and get them squared up on the bed. OK. At this point I usually palpate the greater trochanter. If the child has iliotibial band tendonitis or greater trochanteric bursitis, then the kids are usually very tender right in this spot. And really that's the only possible source of the pathology if the child is tender directly over the greater trochanter. Next thing we do is have the child lift their leg up in the air. I'm going to let go. OK? 

Stewart, patient: Uh-huh.

Dr. Sankar: I want you hold your leg up in the air, and go ahead and push against my hand. And I'm testing abductor strength here, similar to the way I tested it when the child was walking, but of course this a little bit more of a focus test. After that you can look for tightness in the iliotibial band. This is an over test. The iliotibial band runs from the pelvis all the way down to the knee. And if I take the leg and just gently let the knee drop, and if there's a lot of tightness and resistance, it means the iliotibial band might be very tight. If it drops quite easily down to the contralateral knee, it means that there actually is a pretty good flexibility in that tendon. 

And that's our general hip exam that we perform here at CHOP which gives you, I think, a nice screening test to look for intra-articular and extra-articular hip pathologies.

Topics Covered: Developmental Dysplasia of the Hip (DDH)

Related Centers and Programs: Division of Orthopaedics, Hip Disorders Program, Young Adult Hip Preservation Program