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Hi, it is Tom here from Running Physio. Today I want to talk to you a little bit about hip dysplasia, which is actually one of those conditions which is surprisingly difficult to spot and as you'll see in a little while, can take quite a while to diagnose, but will be there in quite a few patients that we see in clinic.

Now, I recognise for me, this is an area I wanted to learn more. So I've dived into the research and I'm going to summarise some of the findings from that in this video to help you to spot hip dysplasia in patients that you see in clinic. I'm going to also add some of the key research papers that I've identified so you can explore in more detail.

We've also got our free running injury videos, including videos on shin pain assessment and treatment. Lots of gems in there for you to use in clinic with your patients.

So let's start with some surprising information that I found out from some of the literature that I was reading. So we think that hip dysplasia is prevalent in approximately a third of patients with hip pain that are presenting in primary care. And yet in one study it found an average of around five years to diagnose. So it may actually be quite common but missed. It's not something we necessarily always suspect, and yet it can lead to significant limitations for patients, pain with activity, pain with walking and limping in some cases as well. So it can have quite a big impact on people's lives. Let's have a look at some of the common presenting features to help you to spot it. Hip dysplasia is typically going to be seen in a young female patient with an insidious onset. They're frequently going to describe groin pain, maybe with some lateral hip pain as well. Now we can think of a number of different pathologies that might present in this way. But these would be some of the key signs. It's often aggravated by walking, running and impact. It may also be aggravating by pivoting movements and prolonged positions like sitting in some patients. And probably one of the most useful tests that we have would be FADIR test, which is likely to be positive in most patients with hip dysplasia.

So depending on the research you look at, Nunley et al found 97 percent of patients had pain with the flexion-adduction-internal rotation test or a larger review more recently found about 58% do. Now, of course, this doesn't tell you that it's definitely dysplasia. You can also get pain from other areas. You can get femoroacetabular impingement will also be a positive with FADIRs. But it may add to your suspicion. Approximately 80% of patients with hip dysplasia are going to have mechanical symptoms of catching, clicking, locking, or popping. They may describe that the hip feels unstable. So again, that should lean you towards considering this as a diagnosis, and it seems that the left hip is more commonly affected than the right.

When we think about what hip dysplasia is, it's a lack of coverage of the femoral head from the acetabulum. Actually, that may lead to increased range of movement at the hip rather than decreased range. So that might be a key differential between hip dysplasia and a more acetabular impingement, where we often see reduction in internal rotation or flexion. And it may be associated with hypermobility. So looking at our more broad tests of hypermobility can be useful as well, because if you've got that combination perhaps of some dysplasia and some general hypermobility, that's going to affect the stability at the hip. There may also be a family history of hip pain or dysplasia as well. So important to gather that family history.

Now, there are some tests that have been looked at by Reiman et al in 2019, looking at tests of instability and dysplasia. So they may have positive tests with a prone instability test or the hyperextension external rotation test or abduction–hyperextension–external rotation test. And I'd look at Michael Reiman's work for a little bit more information on that.

So if you have a, young female patient that's presenting to you in clinic with groin pain, maybe a bit of lateral hip pain as well, if it's brought on by walking, running an impact, if they've got a positive FADIRs test, but they don't seem to have a limit in range, in fact, they seem to be perhaps a bit hypermobile. Those things should be, waving a flag and leaning you towards dysplasia as a possible diagnosis, particularly if they have previous family history. It can impact on activities like walking. Sometimes it can lead people to reduce their hip extension in walking and running because that's a position that often feels unstable for them. So you might see that if you're analysing their movement patterns potentially.

One thing that we often see in runners, which is obviously my specialist area, is a lot of them are diagnosed with hip flexor tendon pain. We know this can be a bit of a red herring for things like femoral neck stress fractures. But it's also a bit of a red herring for dysplasia too.

A recent research from Jacobsen et al looked at the prevalence of muscle or tendon-related pain in people with dysplasia, they found approximately half the patients with hip dysplasia may have iliopsos-related pain, so it's likely to be secondary to the dysplasia.

So we have this phrase that Dr. James Noake made popular "It's never the hip flexor". And this is another example of where in runners in particular, we know it's rarely the hip flexor in isolation. There can be other underlying pathologies. So if you've got someone presenting with hip flexor related pain, again, that fits some of those characteristics we've talked about. There may be some underlying dysplasia of the hip that's leading to some irritation.

Also, hip abductor related pain was also quite common in these patients too. So, we do see this around the hip, that one pathology often then presents with others or pain in the surrounding area, and that can make diagnosis a little bit more tricky.

So we've got some of the key features there for you to identify. Let's compare it to some other causes of pain around the hip region just so we can, help with a differential diagnosis. So if we're comparing hip dysplasia versus gluteal tendinopathy, gluteal tendinopathy can present with pain in the lateral hip, although hip pain may be less common in the groin. So if we compare the two with a hip dysplasia, it's typically younger female patients. So I believe Nunley et al the average age was about 24. With gluteal tendinopathy, it's more common in women over 50. I believe it's been found to affect about one in four women over the age of 50, so slightly different patient demographics.

With hip dysplasia, it's going to be predominantly groin pain, possibly with lateral hip pain too, whereas gluteal tendinopathy is predominantly lateral hip pain, although there are studies showing that you can have spread of symptoms into different areas. Unfortunately, of course, with diagnosis, it's never as clear cut as you think.

With hip dysplasia, we would expect a positive FADIRs. Sometimes positive in gluteal tendinopathy because we're combining flexion and adduction, but we'd be more expecting positive FADERs. So, flexion-adduction-external rotation test or doing things like your sustained single leg balance or palpation of the gluteal tendon, more likely to be positive in a pure gluteal tendinopathy. With hip dysplasia, we might have these mechanical signs and symptoms like feelings of instability, clicking or locking, et cetera. But just to muddy the waters, you can have this coexisting tendon pain that's quite common. So probably that one of the key things there will be the age, demographic.

We do see tendon pathology in younger patients with hip pain, but it is probably more likely to be the older demographic there. What about femoral neck stress structure then? We talked a little bit about this, and when I was putting this together, I was actually surprised how much overlap in symptoms there are. So if we look at hip dysplasia and femoral neck stress fracture side by side, in both, they're more common in females. In Nunley et al's paper, 72% of the patients with hip dysplasia were female in that study. And we know generally stress fractures are more common in female.

And male runners both can present with groin pain but you can have spread of symptoms in both, perhaps lateral hip pain with a dysplasia, but also potentially thigh pain with a femoral neck stress fracture. And both actually can have a positive FADIRs test, a positive flexion adduction internal rotation test.

I think perhaps in mechanical symptoms like the locking and instability we've talked about are going to be more common in dysplasia due to the nature of the pathology. But both can have coexisting muscle and tendon pain. Again, hip flexor tendon pain is quite common in people with a femoral neck stress fracture. So really, if that's presenting in a runner, you need to be considering what's driving it, what's underneath that. Both can be aggravated by walking impact and running. It's load-bearing stuff that tends to irritate femoral neck stress fractures and also seems to be painful in dysplasia.

Both can have night pain. Nunley et al reported about 59% of patients in their study of dysplasia had night pain, which we know can be a feature of stress as well.

Now, one difference that you might be able to find on examination in hip dysplasia, you may have apprehension or instability in end range extension positions that you wouldn't necessarily expect in a femoral neck stress fracture. Things like the prone instability test may be positive. There may be symptoms in extension, perhaps with walking and running as we've touched upon. And with the femoral neck stress fractures, you probably would expect the impact tests, so jogging on the spot, jumping in place, or the hop test to be immediately fairly provocative, particularly in the more severe cases.

So this might help you a little bit with your differential diagnosis between the two, but certainly there's quite a lot of overlap in terms of the patient. If in doubt, particularly with femoral neck stress fractures, we recommend urgent investigation. An X-ray can help to identify dysplasia or femoral neck stress fracture, although it's not particularly good at picking up stress fractures. But an MRI would be the gold standard for assessment of bone stress injury. So if in doubt, get these checked out.

For differentiation, maybe have a think about the kind of causative factors. So training load in femoral neck stress fractures. You're not likely to pick up a stress fracture without a reasonable training load there. And do they have bone stress injury risk factors? Do they have low BMI or low energy availability? Have they had a previous bone stress injury? If so, that would certainly raise my suspicion of a new stress fracture. And then with the hip dysplasia, if they're generally hypermobile, if they have a family history of dysplasia or hip pain if they have those positive instability tests we've been talking about, that again, should lean us a little bit more towards dysplasia. And I think if you suspect dysplasia it, it I think, appropriate to, to go on, to look at the next steps in terms of investigation, possibly with X-ray or MRI to learn a little bit more about the condition to help confirm the diagnosis. Hopefully that's been useful, given you some of the key features of dysplasia.

Speedy recap of what we've said. If you have a patient coming to clinic, particularly a younger female patient with anterior groin pain may be lateral hip pain as well. If they don't seem to have limited range, perhaps they seem to have excessive range in the hip. Perhaps previous history of hypermobility, these things should be making you consider dysplasia, particularly if they've got mechanical symptoms like instability, clicking, locking. Any of those features should lead you to suspect dysplasia is a potential option.

Thank you very much for listening. If you've got any questions about this, any comments, any cases you've seen, please let us know in the replies.

And as I said, I put a link to our other running injury content. Do check that out. I'm sure you'll find it really helpful. Okay, thanks again for listening. Bye for now.