Hip vs. Knee OA: Unraveling the differences with Dr. Joanne Kemp

In this episode, Dr Joanne Kemp discusses the difference in assessment and management between hip and knee Osteoarthritis. We differentiated between back pain, local pain and red flags as well as how there may need to be consideration for flexibility training in the hip vs the knee. 

Want to learn more about Hip Osteoarthritis? Dr Jo Kemp recently did a brilliant Masterclass with us, called Hip Osteoarthritis: Optimising your Assessment and Treatment where she goes into further depth on this topic. You can watch her whole class now with our 7-day free trial: https://physio.network/masterclass-kemp

Dr Joanne Kemp is a Sports Physiotherapist and Senior Research Fellow at Latrobe Sport and Exercise Medicine Research Centre, Australia. Her research is focused on hip pain including FAI and early onset hip OA in young and middle-aged adults, and its impact on activity, function and quality of life. 

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Transcript

SPEAKER_01 0:00

Music Often the exercises really overlap for hip and knee OA so you do that hip strength and knee strength and trunk strength is really important as well. But the thing I think that really differentiates the hip is you also need to address that limited range of motion and do some flexibility exercises as well as the more muscle strength type exercises. Music

SPEAKER_02 0:25

Are there differences between the treatment of hip and knee OA? Today we have Dr. Joanne Kemp on. Now, Joanne is a sports physiotherapist and senior lecturer at La Trobe. Now, she covered the differences in assessment and treatment for hip and knee OA, including how we differentiate between the back and more locally the hip and other red flags, as well as how the strengthening component is quite similar. However, there's a couple of additions that we might add for the hip. Now, Jo has done a physio network masterclass on this subject where we dive a lot deeper and you can click in the show notes and give that a try on a seven-day trial. Please enjoy this episode. My name is Michael Risk, and this is Physio Explained. Welcome, Jo, and thank you for joining us.

SPEAKER_01 1:11

Thanks, Michael, for having me. It's good to catch up again.

SPEAKER_02 1:13

You've done a masterclass for Physio Network on this subject, so we're going to hone in on a couple of things. But if people want to go deeper, they can check that out in the show notes. Jo, start with The assessment of hip and knee OA and what are you looking for? What's come up for you recently in the research or in your experience?

SPEAKER_01 1:30

Yeah, it's a good question. So the masterclass was focused very much on hip OA rather than hip and knee OA. So it'd be good to hone in, I think, a little bit on that because that's probably something maybe people have a lot more experience and exposure with knee OA than hip OA. So I think we focus on that with the assessment. So I think the important thing when someone comes in with pain in that hip area in your assessment is to do a really good subjective. And I think if you do that, you should have a pretty good idea of what you're dealing with before you even get to the objective assessment. And then the objective assessment is really just helping you confirm your diagnosis and then get a good understanding of what impairments someone has so that you know what you need to treat. An understanding of impairments might not help inform your diagnosis, but it's as important because then you know what you're dealing with in terms of a management plan. But from a subjective point of view, Really trying to tease out whether you are looking at a pain that's coming from the hip joint is important versus other things that can cause pain in that same area. So obviously ruling out pain from the lumbar spine or pelvis is important. And you can get a few clues by just the location of somebody's pain and also the way they walk. If they have a limp, it's a lot more likely it's coming from their hip joint than coming from their lower back or their pelvis. The other thing to think about is the red flags. Not that commonly, hopefully, but that can present in that areas. Things like body stress type injuries. So whether it's stress fractures, osteoporosis, if someone's had older or if they've had exposure to cortisone, avascular necrosis can be a big one. Again, if someone's had exposure to cortisone or if you think that they've had a lot of exposure to alcohol through their life is important. And then the metastases from the common cancers that metastasize to the hip. So bowel cancer, breast cancer, the gynecological cancers and prostate cancer can often metastasize to the hip joint. So asking someone about their history of cancer is really important in that subject because the first thing you want to do is rule out everything else. And once you've done that, then you can start to hone in a little bit more on the hip. Age gives you a lot of clues as well. So if someone's over 45 and you think the pain is coming from the hip joint, then you can be reasonably confident that they have osteoarthritis. And the guidelines for diagnosing HIPAA don't actually require energy to form a diagnosis of OA. One of the key things is that someone's aged over 45. So the age will give you some really good clues. Then also asking them about their history when they were younger, because we know that hip dysplasia, for example, really leads to an increased risk of developing hip OA in later life. So asking them if they had clicky hips or if they were diagnosed with dysplasia as a baby or as a child or an adolescent. But also can things like FAI syndrome also increases your risk of OA? So did they have hip impingement when they were younger? Did they have sports-related groin pain? That can give you some clues as well. People who have done a lot of high-impact sports when they were younger also increases the risk of hip OA. So, asking about their sporting history when they were younger is important. And also asking about their work history, so current and past, because if someone has done a lot of heavy manual work, again, that does put them at increased risk of hip OA. So, gathering all of that information can really help with your diagnosis. And then in your subjective, also asking them about functionally what they can do. So the classic indicators for HIPAA or asterisk signs are pain in sitting is a really, really common one. And then pain getting in and out of the car because you're getting into that flexed and rotated position and also putting on shoes and socks. So Pain and also restricted movement in those things. So if someone says to you, it hurts putting on my shoes and socks, but also if they say, oh, it's just really stiff and I can't reach down to that foot. Again, that's a really classic warning sign for hip OA as well. The other thing that's a little bit of a giveaway that you're dealing with osteoarthritis is that morning stiffness that doesn't last too long. So 30 minutes or less, they get up out of bed and they're just a bit stiff. putting on shoes or whatever. And then once they warm up and have a shower, that stiffness goes away. That short lasting morning stiffness is also a classic sign of osteoarthritis generally, whether it's hip or knee. And then the location of the pain, which I mentioned at the start, gives you a lot of clues. So if the pain's in that anterior hip and groin region, it's usually the hip joint. But the other thing that's really interesting with hip OA is that people might not actually have pain in and around the hip. They might have pain in their knee or even down in their lateral shin, lateral ankle, and even into their foot. So if someone comes and you ask all those questions and their pain's sort of in their knee or down in the lateral shin, foot area, just be really cautious that It might actually be their hip joint. So make sure when you're doing your objective assessment that you do all of those tests for the hip joint that we'll talk about in a minute, because I've had a number of patients who have pain in their knee and who get sent to an orthopedic surgeon for knee OA. Luckily, some of them, the surgeon's catched and know it's actually your hip, not your knee. But I have had a couple of patients over the years where they've actually progressed to have a knee replacement and it was actually their hip all along. So just be really cautious if someone's in that age group and they have some of those risks back just to hip OA, they have restrictions in their hip movement and pain in their knee or down further that you just rule out the hip as well because it could be hip OA.

SPEAKER_02 6:37

Jo, you're a genius and I'm blown away and I've never taken two page of notes just on this objective. That was so super thorough. I have lots of questions on some of those things. Take me deeper into the work history. That really piqued my interest. So you mentioned that if that had high impact work in the past, that was a precursor.

SPEAKER_01 6:57

Yeah.

SPEAKER_02 6:58

Is that on imaging or developing the symptomatic experiences of OA?

SPEAKER_01 7:03

It's a good question. So it's the heavy manual work and the high impact sport. And it depends on the study that you're looking at. So some studies will use imaging as their marker for arthritis and others will use a combination of imaging and symptoms. And the studies that have looked at that often include people who have been referred for hip or knee pain. So it's usually a combination of both imaging and symptoms.

SPEAKER_02 7:25

Yeah. Okay. That's good. The second thing that came up for me while you were speaking to that is, do you have a couple of go-to tests that might distinguish between or rule out the back when it is a hip? What do you look for there?

SPEAKER_01 7:38

So, you can look at your lumbar spine, repeated range of motion tests, and particularly repeated extension and combined extension and rotation. And they actually have a really high sensitivity. So, The studies that look at their sensitivity, we're talking in the high 90s sensitivity. So what that means is that if you do those tests, so if you do lumbar extension, repeated lumbar extension, combined extension rotation, and also straight leg raise, it's a really high sensitivity as well. So if you do those tests and it doesn't reproduce their pain, then you can be pretty confident their pain is not coming from their lumbar spine.

SPEAKER_02 8:14

Yeah. So those tests ruling out the back, plus the history, plus the location of the pain in the hip,

SPEAKER_01 8:20

Exactly.

SPEAKER_02 8:21

You'd be pretty confident. And 45 plus.

SPEAKER_01 8:24

That's right. And then you can also use some of your hip specific tests. So tests like the flexion adduction internal rotation test and also internal rotation at 90 degrees. So with the FADIR or the flexion adduction internal rotation test, that also has a really high sensitivity. So that test does not reproduce their pain. And sometimes you have to work into it a little bit. Like it might just go boom, boom, boom. You've got to perhaps test out different ranges of flexion and adduction as you do it. But if you can't find their pain with that test, it's probably not their hip joint. And with internal rotation, you'll often see a reduction. It might not be painful, but in most cases with hip OA, they will have lost that internal rotation range. So you'll either see it reduced compared to the other side, But sometimes they've lost it on both sides and they might just have terrible internal rotation range. So that's a real giveaway sign as well. And that's why they lose that rotation. They also lose external rotation too. So they're often combined rotations really limited. And that's why things like getting shoes and socks on are really classic because you have to, as well as flexing, you've got to rotate to get your hand down to your foot. So because of that loss of rotation and also getting in and out of the car, that's why they classically are really impaired in limited in their range and sometimes painful as well in someone who has hit by way.

SPEAKER_00 9:34

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SPEAKER_02 10:01

I'm glad you mentioned the Fadir because the last question that came up for me was if we're getting that referred pain down to the shin as the example you gave, how would we know that one? Would we do the Fadir and they're like, oh, it's actually making that worse down there? Or do you see that that hurts locally?

SPEAKER_01 10:16

So it can be both. What can often happen is when you go into those provocative tests for the hip, They go, actually, I'm getting that pain. When you do that, I feel it a bit down in my foot or my knee or whatever, but that's giving me groin pain. I didn't realize that was sore because they often avoid that position because it's painful. But you'd see that limitation in their range, potentially pain up around the hip as well as where they report pain and the limitation in their movement as well at the same time, which can be limited flexion as well as the rotation movements.

SPEAKER_02 10:45

That's good clarity. So take me to treatment. We're pretty confident it's HIPAA. And now what do you see in the evidence and in your experiences?

SPEAKER_01 10:52

So there's some really good evidence that shows that exercise-based treatment works really well in HIPAA. So there's a really nice RCT that was done in Norway, probably about 10 years ago now, where they did a combination of Strength training. So they did classic strength exercises. So like weighted cable or band sort of hip abduction and adduction, hip extension and flexion. And they also strengthened up the thigh. So they did some quad strength and hamstring strength. So leg presses and leg curls as well. and extensions. So they said they did strength. They did some neuromuscular type exercise, neuromotor exercise, so some balance and lunges and those sorts of things. And then they also did some flexibility training. So they incorporated flexibility training into the hip, which I think is where the hip differentiates from the knee. Often the exercises really overlap for hip and knee OA. So you do that hip strength and knee strength. And strength is really important as well. But the thing I think that really differentiates the hip is you also need to address that limited range of motion and do some flexibility exercises as well as the more muscle strength type exercises. And so that can be trying to improve flexion range, improve the rotation range, improve other ranges as well. You might need to address muscle strength. length issues as well. So often they will be tight through hamstrings, quadriceps, hip flexors, glutes, calves, might all be tight. So you may need to do some stretching type exercises to try and improve their mobility. And that seems to be a really key element in hip OA treatment. So it's exercise-based treatment. And then the other thing is giving them the confidence to move and to exercise because often they're frightened to move because they're scared that it will reproduce their pain. But they also have this perception that Movement and exercise is going to wear out the cartilage in your joints and make their arthritis worse. And we know in the knee that a moderate amount of exercise is actually protective for joint health. So some studies have been done that show that sedentary people have a higher risk of knee OA than people who do a moderate amount of running. And so there's that sweet spot in the middle with physical activity where it's actually really good for the joint and protective for the joint. We don't have the evidence really in the hip But I can't see why it would be any different. Like I don't see why keeping the hip still and not moving it would be better for the hip than moving it and loading bone and loading cartilage and strengthening muscles. So the other important element as well as the specific exercise program is to educate people about that and give them the confidence to move and then also give them a physical activity program. So don't just give them the rehabby exercise program. but get them doing physical activity and trying to really meet the WHO physical activity guidelines that say you should be doing 150 minutes of moderate physical activity or 75 of vigorous per week as a minimum, and also doing two strengthening sessions per week as a minimum. So those rehab exercises can fall into that twice a week strength work, but getting them to do that physical activity as well is really important. And then the other thing that's important with the hip, I think that again, differentiates from the knee is is that inflammation is a really big problem in the hip. And I think we see synovitis and inflammation as can be the driver of hip OA. So often someone might have really bad x-rays and be getting away with it. And then something tips them into an inflammatory type state and you need to address the inflammation. And so that's where anti-inflammatories might be important in this patient group, sort of oral anti-inflammatories, whether it's non-steroidal or steroids. And also thinking about If they're in the obese category or if they have a lot of that central adiposity, we know that that drives inflammation. So you might need to look at some dietary intervention or dietary advice to address that as well. So really try to address systemic inflammation as well as the physical things. So we're really good at the physical stuff, I think, as physios, but sometimes we forget that often what we do isn't enough and you may need to add in some medical interventions as well.

SPEAKER_02 14:32

Jo, that's super thorough. We've got about one minute left. I'll put you on the spot a little bit, but how would you have that conversation with a patient approaching that there could be an inflammatory component to this and there's other things we might need to look at? How might you suggest that or broach that?

SPEAKER_01 14:47

I just say that we know that the hip joint's getting inflamed and so we need to do something about this inflammation. And I say that there's different ways you can do it. So if someone doesn't seem to have an issue with their body mass, leave that alone and just send them to their GP. So if I will always get the GP involved if there's any sort of medical management needed and just do a letter to the GP and ask the GP for some sort of anti-inflammatory guidance and assistance. If the dietary thing or the BMI thing It's a little bit of a tricky one to address. And I think patients will often know themselves it's there. And I think you can just broach it around the subject of we know inflammation is a problem. Everyone over the age of 45 has issues with central adiposity, which is where you get that extra adipose tissue around your middle. That's something that we often need to address as well. And most people are open to that conversation as well.

SPEAKER_02 15:37

Jo, thank you so much for your time. Pleasure, Michael. And just a reminder for the listeners that we will have the link to the masterclass that you've done on this topic in the show notes and people can try that for free for the very first time. Thank you again, Jo.

SPEAKER_01 15:51

Pleasure.