all. This discussion is on how the foot and the ankle impacts the hip. My name is Dr. Ben Kivlin, I'm from Duquesne University, the chairperson of the physical therapy department and program director of our PhD studies in rehab science. So I'm honored and privileged to be a part of this virtual lecture series on a topic that frankly I'm quite passionate about and looking forward to a little discussion here and sharing some of the evidence and maybe lack of evidence even that we have linking the foot and the ankle to the hip joint and what that means from evaluation, intervention, and pathogenesis of these conditions. Now as soon as we introduce gravity and ambulation really or the foot hitting the ground and impacting what's going up the entire kinetic chain, that independence that the hip joint may have is now out the window and it's really reliant now on an interaction and an interdependence on all of the other joints and structures in the kinetic chain. And from a rehab standpoint, this is particularly important and where our physical therapists and our rehab specialists become really skilled and adept at looking at really the big picture, how are the other segments and loads of the loading of the other segments specifically affecting the joint of interest or a joint where a patient is complaining of pain or dysfunction. So we can see this little animation here playing on the right of the screen just showing you how foot and ankle mechanics during a squat, for instance, a very functional activity influences how the hip is positioned, how this lumbar spine even is positioned and how the knees positioned as well. So we want to dive into this a little bit more to make this a little bit more clear. And this is where we start to see some divergence here between maybe what a rehab specialist like a physical therapist or athletic trainer might be looking at in comparison to our more traditional medical model. So if you think about how we look at things diagnostically, we have a dysfunction in many cases, it might be someone's pain. And we can use this example of since we're talking about the hip, we use the example of a CAM lesion here. And so the patient may have hip pain that's causing some difficulty and some discomfort when they squat. If we take this from a pathoanatomical approach, then we've got a CAM lesion that's ultimately leading to delamination or labral tear, ultimately joint degeneration, something that has been studied and established for quite some time now in the literature. And the intervention becomes change the anatomy, do a femoroplasty, remove the CAM lesion. And the hope is that that ultimately leads to a resolution of the pain and normalization of the movement pattern, like it's a squat to return to a level that the patient's satisfied with. When we look at things from the perspective of a physical therapist, or someone that's focused on more or less the movement dysfunction associated with this, if we take a pathoanatomical approach, doesn't necessarily lead us to an appropriate intervention. So in other words, we get to a CAM lesion and a physical therapist can say, well, what, what do I do with someone that has a CAM lesion? Well, there's a lot of different options. We have hip mobilizations, lumbar pelvic mobilizations, hip strengthening, core re-education. Where do all of these different interventions lie to be successful? In our evaluation, if all we're doing is trying to get to a pathoanatomical diagnosis, then we're essentially missing what what we need to be able to devise the appropriate intervention. So we can take more so of a pathokinesiologic approach where we may have hip flexion and a posterior pelvic tilt deficit, or we can even change that into, maybe we have an aberrant motion that's involving limited dorsiflexion. So this dorsiflexion might lead to the changes more proximally with, with how the hip is flexed, how the pelvis is unable to posteriorly pelvic, perform a posterior pelvic tilt to get out of the way of that CAM lesion. And so we can maybe even restore some of the sagittal motion imbalance that there might be, maybe avoiding some medial knee deviation that leads to hip adduction that we know can approximate a CAM lesion into the hip joint and create some of that pathology. So this illustrates how we can then look at this, the same condition, maybe from a little bit different of a perspective, and perhaps even get to the same outcome of limiting the pain and normalizing a functional movement pattern. So in order for us to understand how much the foot and the ankles is affecting the hip, we first have to look at what is the healthy relationship between the hip and the foot and the ankle. And there's two major things, we could talk about this all day long, but there's two major functions that we see, especially when we're talking about ambulatory beings here. We have to have adequate dorsiflexion range of motion. This helps us accept the weight bearing loads and ultimately maintain sagittal balance. So you can see the picture here on the right, we have an individual on the left with a little bit more space. You can see the knees coming over the toes, indicating a sharper degree of dorsiflexion. And then we have someone on the right side there, granted the bar is in a little different position as well. But we basically see the knee not being able to come over the toes quite as far. And what that causes the subject to do then is to really lean forward and get more of a trunk lean that's increasing the amount of hip flexion required to perform a squat. So it throws, not only does it change how the patient is loading, but it also throws that balance in the sagittal plane off. And the other component of this then that the ankle needs to be able to do, so we mentioned is in maintaining that sagittal plane balance, it really needs to be our suspension system. So the picture here illustrating that when we're on a particularly unlevel terrain, the foot and the ankle is adapting to that so that we no longer have these major deviations. When you look at somebody that's efficiently ambulating or moving, they're very in control of their trunk. That's a characteristic of good mature motor patterns. So that has to occur with a good suspension system as we are looking at the foot and the ankle as a way to adapt to the environment and specifically adapt to the ground. So you can just see the graphs below there showing how much motion, particularly in stance, which is going to be in the middle section here of these graphs, how the foot and the ankle is adapting to the ground. We also need to rely, the other big function of the of the foot and the ankle is to be the lever that ultimately is creating propulsion and power. So our main motor, specifically to our gate patterns, is going to come from the power generated primarily from our ankle plantar flexors. Now two things need to happen here as well. Number one, we have to have plantar flexion strength and power to be able to develop that. That's what you can see on the top graph there. But the other component is that our stabilizing muscles, if we think back at that picture of the all-terrain vehicle and the crazy suspension system there, we have to have our muscles acting like that suspension system to be able to maintain a lever that's going to be able to generate that propulsion and generate that ultimately that power from that. So our inverters and everters of the ankle become very important to basically keep the ankle and on track and to be able to be a powerful lever. Now what happens when we have an unhealthy relationship? Well again we're simplifying this but one of the major factors that's going to lead to an unhealthy relationship is this lack of dorsiflexion. So that's going to really potentially throw off our sagittal plane balance and it's also going to reduce our ability to really absorb loads. And so we can see this graph here below showing how the lack of dorsiflexion reduces the amount ultimately has an impact at the hip joint with reducing hip extension. And if you think about how important hip extension is to gait also as a means to generate power but also just to create that symmetry. So let me show you this next slide. A limited dorsiflexion is going to decrease speed, obviously limit the hip extension, but then it's going to require the knee to flex more, the hip to flex more, and you're staying more in a continuum of a hip flexion based type of position and never getting the hip into extension. By default then if the body is forcing the hip then into extension then you get into transference of forces up through the lumbosacral spine as well and those interactions there. So we can lead to further conditions and pathologies that continue to go up the kinetic chain. The other thing that you'll see as we mentioned with decreased dorsiflexion but also decreased plantar flexion strength is that speed and ground reaction forces change and the amount of time that someone is spending on that limb is increased. So if you think about from an arthritic standpoint or joint degeneration, generally someone that has an irritated joint is not going to want to spend more time on that. So there's factors involved with specifically ankle strength that can be a problem for that. Now we looked at gait and gait maybe was a difficult one to start with, but let's look at some other functional positions here that can relate these relationships to essentially to our foot and our ankle and connecting that to the hip. So you can see this animation here on the right side of the screen and the compensation that has to occur whenever the tibia can't rock forward into ankle dorsiflexion then the body naturally is going to fall more posteriorly and then that leads to changes in the trunk angle which you can see makes a dramatic increase in the amount of hip flexion. There's also studies suggesting, I'll show you a video here in a second, that it's not just the sagittal plane but it's also in particular the coronal or frontal plane where compensations can then occur with medial knee deviation being one that places the hip joint in more adduction. So we combine a limited dorsiflexion sets the patient up for limited knee, excuse me, increased hip flexion rather and increased adduction both of which can be provocative positions for someone that is experiencing some impingement or some type of arthritic type of change into the joint. So this is actually a good illustration of a 25-year-old female PT student that came in to us with complaints of right hip pain. Imaging suggesting a combo of a cam pincer type of impingement and you can see just by looking at her squat there there's some numbers there indicating the knee flexion and the overall depth of the squat is rather poor and you can see a pretty significant trunk angle leaning forward with her. What this doesn't necessarily help us appreciate is just how vertical her tibias are when she is squatting here. So this is a patient that is having some problem then being able to bring that tibia over the talus and go into really go into adequate dorsiflexion. So an appropriate treatment for her not just including her hip exercises but being more specific to the foot and the ankle and so you're seeing some different applications of this some that can be done at home and some certainly done in the clinic. So we're seeing examples of trying to mobilize the tibia over that talus to get into some dorsiflexion closed chain dorsiflexion. There's some evidence suggesting that particularly during a squat that ankle range of motion and strength is actually more important of a factor in an appropriate function than hip range of motion and strength is. So there is some evidence behind this certainly. So you may be asking okay well then if dorsiflexion can be a problem how much is enough? Well research would suggest that in a closed lunge or a weight-bearing dorsiflexion position as shown on the left upper picture there 45 degrees of weight-bearing dorsiflexion and then from a non-weight-bearing position 22 degrees of non-weight-bearing dorsiflexion. So there's those numbers seem perhaps a little bit higher than what maybe someone would expect to be functional. So we have to ask we talked a lot about ankle dorsiflexion in that sagittal plane. What about what's occurring in some of these other planes here? And so you can see the animation here in an attempt to go deeper in a squat or deeper with a movement or dorsiflexion has been restricted. The compensation pattern may switch to more triplanar and that would include rotation our transverse plane as well as our coronal plane type of corrections here. So the evidence would suggest that there's some moderate correlation between subtalar pronation and internal rotation of the knee and the hip. So that's what we're seeing in particular on this particular animation. So that raises the question as to should our hip strengthening program or I should say hip conservative hip training program include interventions then for the foot and the ankle and the answer certainly is one of those strong maybes and it probably has to at least be examined as a potential option. So we can engage the hip rotators here as we're seeing in this animation as the same time that we're actually trying to engage and encourage the intrinsic muscles of the foot to be able to function to avoid a collapse of the of the medial longitudinal arch and a more pes planus type of position. So short foot training does become something that may have an impact all the way up the kinetic chain. We actually looked at some testing for this comparing dorsiflexion range of motion and foot posture between individuals that both passed and failed a single leg squat test. So we've looked here at Duquesne quite a bit at the single leg squat test and the interesting thing that we found was that there was not significance with different foot postures and dorsiflexion range of motion as it related to the single leg squat. So why am I throwing that in there is that the single leg squat did not seem to factor in as at least as much in our population in this study factor in the foot and the ankle. So even though I think it also brings up a little bit of an error of our use of tests to really evaluate some of our patients and that we because we were looking more primarily at a single leg squat test we didn't necessarily incorporate much functional evaluation of the hip joint or excuse me of the ankle joint related to the hip joint. So this is pretty, you know, it's complicated, it's confusing because some research out there, very recent research, would suggest that increased internal rotation or increased passive stiffness rather leads to increased internal rotation of single leg squat. So it's a very hip centric type of condition where hip strength and foot alignments and things that we have been conditioned to think can change our mechanics really didn't necessarily contribute to the hip internal rotation movement that is sometimes seen. So we don't know still, you know, where things lie and I think part of it is that there's that it's so multifactorial that it's difficult to tease out. Where we may be able to maximize some some of our understanding with these functional tests linking the foot and the ankle to the hip is looking at the step down test and our study previously in addition to a more a more recent study done by Foster showed an association of ankle dorsiflexion to hip and pelvic mechanics for patients with hip related groin pain. So very specifically those with decreased dorsiflexion had an increase in anterior pelvic tilt and a increase in the contralateral hip drop. So what that essentially does is that that associates with greater hip flexion, lack of clearance of any anterior superior type of acetabular coverage and then also it factors in a that there's increased hip adduction both of which we know that are our common mechanisms or at least if not mechanisms aggravators of femoral acetabular impingement. This is taken from another study that just showing the lack of ankle dorsiflexion leading to greater hip adduction. So that you can see here they they use the step down test again and then altered altered the amount of dorsiflexion that was available to the subjects and then looked at how much medial knee deviation or hip adduction was occurring here. So interesting enough that with regards to hip adduction that that the lack of dorsiflexion certainly seemed to impact coronal plane motion here. It did not find the same factor really involved with increasing dorsiflexion did not did not lead to increased hip internal rotation. So some factors there that were probably affecting a little bit more of of more the coronal plane necessarily in comparison to the transverse plane with rotation. So the evidence is still unclear but I think we're getting a little bit more of a picture and some things that we can glean from this presentation hopefully is that there's some evidence that suggests that there's an interaction and an interdependence between the hip and the foot and the ankle complex. And hip pathology as we know is multifactorial and that's why I think it's sometimes hard to show the statistical significance that that may be of interest that that it's so multifactorial that that that it's the distal etiologic and compensatory movement patterns are very subtle but they do exist throughout the entire kinetic chain. There's evidence out there that would suggest that foot and ankle valuation in particular that looks at ankle dorsiflexion range of motion and strength and also strength really of the ankle and all of the planes of motion is certainly supported. The bilateral squat single limb load tests are useful. We saw how the single or excuse me the step down test can provide some greater context to specifically how the foot and ankle are relating to the movement pattern up more more proximally at the at the hip joint and that effective interventions aimed at the foot and the ankle might explain why we're not always very successful in not only reducing pain but sometimes even post-surgically patients still have these abnormal types of movement patterns in their gait and then their squatting. Their pain and function may have improved but not necessarily their mechanics. So that would suggest that maybe there's some other factors involved and that may include the foot and the ankle. I thank you so much for the time and listening to this presentation. Have a good day.

foot

ankle

hip

kinetic chain

dorsiflexion

rehabilitation