[Physio Explained] Clinical pearls for assessing hip dysplasia with Andrew Wallis

In this episode, we explore the assessment of hip dysplasia, focusing on the condition's definition, the differences between extension and flexion-based movements, and both subjective and objective assessment techniques. We discuss the importance of observing gait, head of femur translation, single leg stance, and various special tests, including apprehension testing, to diagnose and understand hip dysplasia. 

Andrew is an APA Sports and Manipulative Physiotherapist who is currently employed at St. Kilda Football Club (since 2007) and works privately at Melbourne Orthopaedic Group Sports Medicine. Over the last 20 years, Andrew has worked in both a clinical setting and within the elite sporting environment at Melbourne Victory, Adelaide Thunderbirds, SACA Redbacks, V8 Supercars, triathlon and athletics.

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Our host is @sarah.yule from Physio Network

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Transcript

SPEAKER_01 0:00

A normal hip is like having a tennis ball resting in a bowl where if you swilled it around the tennis ball would stay in the bowl because it's contained by those porcelain margins whereas dysplasia is more like having a tennis ball resting on a saucer as in a cup of tea and saucer. So not as much porcelain around the margin of the saucer and therefore a propensity for that ball to move. Now I think the problem then with that ball moving is it bangs into the margins, it hits the labrum, it shears the chondral surface, it irritates anything around that area.

SPEAKER_02 0:38

How is hip dysplasia defined? Who does it affect and how does it present subjectively and objectively in our assessments? Today we are lucky to have Andrew Wallace joining us for part one on hip dysplasia focusing on assessment. Andrew Wallace runs the Hip and Groin Clinic in Melbourne and over the last 20 years he has worked both in a clinical setting and within the elite sporting environment at the St Kilda Football Club, Melbourne Victory, Adelaide Thunderbirds, SACA Redbacks and V8 Supercars. You're going to love today's episode with plenty of clinical pearls. I'm Sarah Yule and this is Physio Explained. Well, Andrew, welcome to the podcast.

SPEAKER_01 1:24

Thanks, Sarah. Great to be here.

SPEAKER_02 1:26

And tell me, how's the week been?

SPEAKER_01 1:29

Pretty good, yeah, yeah. And I've had a busy clinical week seeing a majority of hip and groin patients, but I've actually got a confession. I'm sitting next to the fire having a red wine as we speak because it's pretty chilly outside.

SPEAKER_02 1:42

What better a location than to launch straight into assessment of hip dysplasia?

SPEAKER_01 1:48

Very true.

SPEAKER_02 1:49

Let's get into it. I'm curious. In terms of the definition of hip dysplasia, how would you describe or define it?

SPEAKER_01 1:57

Yeah, good question. I guess any dysplasia is a variation from whatever normal is. I think when we talk about hip dysplasia, though, we're really predominantly talking about the acetabulum and the fact that some portion of it is shallow. That could be anterior, it could be lateral, it could be posterior, it could be global, it could be the whole thing. But I think as we move through our knowledge of hip dysplasia, we're including the femur a lot more now. So things like femoral anteversion, which is intimately involved with dysplasia, and we can talk about it if we get time. But I think both of those sort of come under that definition. It's interesting, I say to my patients, because I think it's nice to have a really easy take-home message, I say that a normal hip is like having a tennis ball resting in a bowl, where if you swilled it around, the tennis ball would stay in the bowl because it's contained by those porcelain margins, whereas dysplasia is more like having a tennis ball resting on a saucer, as in a cup of tea and saucer. So not as much porcelain around the margin of the saucer and therefore a propensity for that ball to move. Now, I think the problem then with that ball moving is it bangs into the margins, it hits the labrum, it shears the chondral surface, it irritates anything around that area. And that's where we get most of our pain from, I think, is either the labrum or the synovium or the capsule, those structures around the peripherum and then potentially even from the surrounding tendons, so laterally into the colluteus minimus and medius and anteriorly potentially into psoas and we shouldn't forget recfem because I think that can be a bit of a pain generator as well.

SPEAKER_02 3:36

And so you spoke about before the structures of the hip that dysplastic hip will typically have or be impacted upon. How do they typically present subjectively? What will they describe?

SPEAKER_01 3:51

It's a good question. Look, I think Our biggest issue at the moment is probably differentiating between FAI or femoroacetabular impingement and dysplasia. And I think that many of those who present with dysplasia have often been told, whether that be incorrectly or correctly, that they do have FAI. And so many of them present with what they think is anteromedial pain or which is sort of reinforced by the treating clinician. And they describe things that pinch, so squatting, lifting the knee into flexion, going into positions of flexion, adduction, internal rotation. But the reality of that is that I think it is more an extension bias pain. So the pain that we think we see in dysplasia is really definitive. We think we see anterior and anterolateral pain in those that have dysplasia. And we think we see more anterior and anteromedial pain, so groin pain, if you like, in FAI. The thing to remember about dysplasia is it is directionally dependent, the presentation of symptoms. So what we see is a situation where if someone has an anterior insufficiency, they will often have anterior pain. If they have more lateral undercoverage, it'll be lateral. And those that are one in six of them that have posterior insufficiency will see the pain more posteriorly. So I think that that's something to be really recognizing and something that's really, really important. Then it comes down to what do these people do that's going to bring it on? So I think most of the time they present most with an insidious onset of pain. I don't think it's normally sharp. It's more a dull ache. As we said, the symptoms are primarily directionally dependent. And I think most people will volunteer symptoms that are flexion-based. So walking upstairs, walking on an incline, gym-based activities that require you to squat or lunge or whatever. But I think it's really, really important that the treating clinician is aware that it is likely more an extension-based cause. So what I say to people then is, we need to push the envelope and ask about those symptoms because they're often not volunteered. So when you push it, People say, yeah, it is. It's when I stand for a prolonged period. It's when I lunge. Oh, so on the front leg. No, no, no, no. On the trail leg, like the leg that's being stretched. When I walk or I run, it comes on. So again, we have to ask the question, was it on the front or the back leg? Because most of the time it is on the trail leg. And so we see people who go to parties and potentially wear, say, high heels and stand for a prolonged period and fall into a sway back posture. And they tend to get those anterior symptoms because I think the hip is going into an extended position. We know we've only got sort of 10 degrees of hip extension. And I think a lot of them use up that isolated hip extension when they stand in sway and they're pushing on the front of the capsule, the synovium, the labrum, whatever it might be. And likewise, when they're walking or running, they tend to take a long stride, but it tends to be on that trail leg that they're getting the symptoms. And then I think other things they potentially present with is they'll describe mechanical symptoms. We're just not exactly sure what they are. So I'm talking here about catching, clicking, popping, locking, that sort of thing. But as we know, with any noise, it can be intra-articular, like it could be truly a labral tear or ligamentaries or something like that, or a loose body intra-articular. But probably in these typical patients, I think it is more likely that what we're seeing is that The tendons, recfam or psoas are flicking over the head of the femur or over the iliopectinal eminence as we go towards extension and particularly if it's brought on with some rotation. And then I think they often describe a feeling of instability. And I think that's through weakness more than anything. I don't think it is an instability issue. I think they get pain inhibition.

SPEAKER_00 7:50

This podcast is sponsored by Cliniko.

SPEAKER_02 8:21

It really does highlight that relevance and the importance of the follow-on questions and asking those specific questions because those are often where the hidden gems are. So it sounds like you will specifically ask about stairs, running, those sorts of things. Are there any other questions you typically find reveals a lot?

SPEAKER_01 8:43

No, other than asking some questions regarding a subject about what their rehab has been in the past. because I'm sure we'll talk about this when we get to rehab, but there's a few things that instability really doesn't like as far as rehab goes. One of them is extension. So being forced into extension during, say, a hip flexor stretch when someone's told, oh, you know, you're really tight in there and they haven't recognized that that tightness is hypertonicity and they try and force through it. So I think this is actually a really good question by you because I think it highlights the things maybe we shouldn't do. So I wouldn't force extension. I'd use myofascial techniques and things like that to reduce tone. As long as we are re-strengthening that person and retraining movement patterns, that's okay. The other thing they really don't like is clams. I think there's two reasons for that. One is we know once you bend past 45 degrees that the abductors become internal rotators. So I think often what happens is you get a reduction in the external rotator capacity of the hip. And because they become abductors, the abductors become internal rotators. And what takes over is iliacus. And iliacus is a strong external rotator. It's the only one that can work in that position. And it frictions across the front of whatever's already irritated, the labrum or the rim. And most people you speak to won't like that. The other thing is that clams effectively take you into a faber position, flexion, abduction, external rotation. And we know that anyone who has femoral anteversion can't do that because they get a bony block at the back, a contact between the posterior acetabulum and the posterior aspect of the neck of the femur, and then levers out the front. So we're a little bit cautious about faber maneuvers, clams, that sort of thing. And I think that's why stretching into that alleged short adductor position of splaying your legs like a butterfly, frog leg positions, they don't like that either.

SPEAKER_02 10:41

Which I suppose will lean right into the objective assessment. Flowing on from your subjective, what do you typically see in your physical assessment?

SPEAKER_01 10:51

Oh, look, I'm a big fan of identifying things as soon as people come in. And I think often their gait is a bit of a giveaway. I think they either have a Trendelenburg gait or don't forget the old Gluteus Medius gait so that Trendelenburg is when we drop down. Aglutius medius is when we sort of hitch up to prevent dropping down because they know they're a bit weak and they're going to drop down. I'll talk about that a little bit in a minute. I don't think as therapists or clinicians, we're particularly good at examining extension. And unfortunately, we need to be pretty good at it to diagnose dysplasia. And we'll get there, but it's the new frontier. So I think identifying a swayback posture is really key. And look, you can go online and see that, but The definition of a swayed back really is that the pelvis sits in front of your shoulder and your foot line or your ankle line. And so effectively, they're standing in extension. But I think the thing that often goes with that is posterior pelvic tilt. And we'll talk about correction of that later. But basically, I think about that someone resting at the very end of range. You imagine if you took your shoulder into position. flexion, abduction, external rotation, and held it there for a prolonged period, the front of your shoulder would be screaming. And I think that's what happens a little bit in this. So just identifying their standing posture is absolutely critical. I don't think we're particularly good at identifying head of femur translation. And so two things we tend to do are ask them when you're looking at their lumbar spine, ask them to bend into extension and palpate the back of the great trochanter, which is about as close as we can get to feeling the head of the femur. I'm not foolish enough to believe we can feel that, but I think you can note someone translating forward with that. So we identify that when someone bends into lumbar extension, they should have symmetrical and minimal anterior translation of the head of the femur. We shouldn't have asymmetrical movement and we certainly shouldn't have excessive movement. And then To follow that up, we then ask someone to stand on one leg with our thumbs still behind the agrotricantra and identify whether they translate significantly forward there. And I think that's another key element of the assessment. And then all the stuff I think that everyone knows. So making sure that we look at single leg stance and identify whether they have a loss of lateral pelvic stability or femoral rotational control. And then doing the isolated testing. We use a Hogan handheld dynamometer to look at abduction. adduction, IR and ER, and we pretty much follow Christian Thorberg's work of sitting or lying in supine and doing that in a neutral position and then turning into prone and doing the testing. Part of the reason we don't test in 90 degrees, so in seated for IR, ER is what we discussed before, that your function around the hip, and Newman's work showed this, but your abductors become internal rotators and your external rotators become abductors. So I think we've got to be a bit careful about what position we test in. And we've got some figures that we use around that. Obviously, it depends what you're using, but if you're using newtons, we'd like people to have coronal plane strength of abductors and adductors around 150 and 135 for the rotators, internal and external rotators. And that obviously is variable depending on your bias to whatever your sex is or your size and all those sort of things that we account for. And just to point on that, I think people can be incredibly strong when they are isolated tested, but not so good when they do dynamic things. So you look at these people, they blow it up, the machine, but their single leg control is terrible or vice versa. We see people with amazing control and we see them when they do an isolated test, they're not so good. So I think we've got to do both. Other special tests for dysplasia, I think the positive apprehension or relocation test. So we tend to do it in a modified Thomas test position. I think it's a much safer position to do it in. I think you can see the patient's face as you Take them into extension and you can relocate it with your hand. It's very similar to the shoulder apprehension test. There are some very wise people who always said to me, do your apprehension and relocation test in a standing position where a patient could get away from that fear and move the body to get away from an apprehensive position as opposed to lying in supine. I think the same thing here. I feel like a patient could get out of it. Because there are some people who teach you to do it in prone and lift into extension. I think that's a, if you see a lot of dysplastic patients, it's a very fearful position for people because they just have nowhere to go. I say a positive in inverted commas, impingement test, end inverted commas, because they will be sore into flexion, adduction, internal rotation. But as we know, that's not an impingement test. It was originally designed as a labral test. And I do think it identifies some labral irritation, but the likely scenario is that these people have gone into hip extension. They have sheared the head of the femur forward and irritated the labrum from an inside-out lesion. The labrum is now irritated. And of course, when you take it into a flexion adduction internal rotation position, it is sore to do that. It doesn't mean they've got impingement. And then probably the final thing is just to be a bit more aware, again, the new frontier. I think we're a lot more aware now of connective tissue disorders and the accompanying of that. Obviously, we're talking about dysplasia and that's an architectural, morphological, bony type lesion. We get that. But I think we are becoming a bit more aware of the whole package. So maybe doing the tests that we all know, the Baten's test, nine score, which is objective. It has been suggested that we should probably do the Hockham-Graham test as well because that's subjective. And I think that's a really good point. And that's a retrospective test that potentially, let's look at the scenario here where we have an 18-year-old female come in. She's going to present with hypermobility on the Baten score. But a 53-year-old female who is potentially a bit stiffer because we recognize connective tissue stiffness occurs as we get older. We might miss something there because we look at her and she passes the bait and test. She probably has one or two out of those nine that are positive. But if you ask her retrospectively, did you have any party tricks? She says, yeah, I used to be able to hyperextend my elbows and my knees and I used to bump hip out to the side and make that clunking. And so that might be something that we ask retrospectively that gives us a bit more of a complete picture. Because as we know, none of these tests should be taken in isolation. They're all... Exactly

SPEAKER_02 17:16

right. And they flow in from your subjective. I think that's an excellent summary. Can you, and I know you and I have discussed this before in the way of apprehension tests, you've obviously got patients that are apprehensive and they're in pain. There's a whole battery of tests often, and it sounds like you typically more lean towards, it's more a clearance process rather than going through a whole range of tests to confirm multiple times that there is apprehension or that there might be instability.

SPEAKER_01 17:50

Yeah, we teach the courses and we teach all of those tests. And there's three tests, as you know, the ab here and that prone rotation test, all those sort of things. But I keep coming back to what I use clinically and that is the apprehension test in a modified Thomas test position because I think it gives you the answer as many clinicians will say that see a lot of one thing. Once you've got the answer, you don't need to keep looking for it. And

SPEAKER_02 18:15

hopefully you've got a slightly happier hip not having done a multitude of tests.

SPEAKER_01 18:20

Yeah, we've all made that mistake though, haven't we? First year out of uni or we go and do a course and Monday morning the poor first patient gets about 2,000 tests and limps out of there. Yeah, yeah. I'm not the only one who's done that, I'm

SPEAKER_02 18:34

sure. Double check and triple check.

SPEAKER_01 18:36

Yeah.

SPEAKER_02 18:37

Well, Andrew, that was absolutely fantastic. There are so many clinical gems in all of that and I'm looking forward to talking about the treatment side of things as well very soon. So thank you so much for your time.

SPEAKER_01 18:50

Pleasure, Sarah. Thank you.