- Welcome back team to the Building Lifelong Athletes podcast. Thanks so much for stopping by, I really appreciate it. For those who don't know me yet, my name is Jordan Wrennke and I'm in dual board certified position in family and sports medicine. And the goal of this podcast is to keep you active and healthy for life through actionable evidence for education. Thanks so much for stopping by, I really appreciate it. Today we're gonna talk all about something called femoral acetabular impingement, a common cause of hip pain in athletes. So let's get started. First, let's start off with a little bit of anatomy. We don't wanna go crazy on anatomy 'cause I understand most people's eyes glaze over but it is important to understand just the basics so that we can build off of that. So first of all, what is the hip? The hip is a ball and socket joint, right? So the femoral head is articulating with the acetabulum of the pelvis. So the femur is meeting the pelvis and it is a ball and socket joint which means there's lots of range of motion there. But when there's lots of range of motion, sometimes that compromises stability. So we do have to worry about, you know, how do we maintain stability of that joint? Well, typically we have a couple of main things. First is a fibrous capsule. So we have the capsule around the joint and then we also have ligaments to provide stability. In terms of blood supply, it's coming from the medial lateral circumflex arteries and then innervation from a nerve perspective is our branch to the femoral, sciatic and obturator nerve. So a lot of stuff going on there. Another big component I wanna talk about is the labrum. So the labrum, it's a ring of cartilage that deepens the socket, kind of also helps enhance joint stability and helps constrain hip movement overall. And then on top of that, we also have the articular cartilage, right? So this actually lines the acetabulum, providing a smooth surface for the femoral hetaclotigans. And so overall 10,000 foot view is that we have a ball and socket joint, you have lots of mobility, you have multiple soft tissue structures to kind of help provide more stability. So what is FAI? Well, femoral acetabular impingement, or sometimes just called hip impingement simply, it's a clinical hip disorder involving premature contact between the proximal femur and the acetabulum. So we think about once again, the femur is abutting against the acetabulum prematurely or causing symptoms earlier than we'd want it to have. And this is a motion related disorder, typically seamless specific movements, which we'll talk more about. And there's kind of a classic triad. So it's usually symptoms, clinical signs, and image findings. So meaning symptoms, exam findings, and imaging. We all three of those kind of make the diagnosis, but overall we think about the femur and the acetabulum, we're kind of having this quote unquote pinching sensation. That's what we think about with FAI. And how common is this? Well, it's pretty darn common. One study that I was looking at found that FAI was present in about 40% of all hip joint pathologies. Now that's not to say it was necessarily all symptomatic, but 40% of all hip joint pathologies. However, it's very difficult to know real numbers because one study looked at, showed that 37% of adolescent hips showed FAI and deformities, but they didn't have any symptoms. So that's another part we're gonna talk about here is that we see this on x-rays, right? We'll talk about imaging in a second. We can see it potentially, but not everybody is necessarily pathologic or having symptoms. And so that's why one, is it just the shape of the hip? We'll talk more about that. But two, how many people are out there with this that don't have symptoms? We don't know. It's really hard to guess the total prevalence, but long story short, this is not a rare thing. This is not something like, "Oh, I'll never see this." No, if you're seeing patients in clinic, like you're going to see FAI, period. Kind of hinting here that we're talking about imaging and finding things on x-ray, what are the different types of this acetabular impingement? So there's kind of two main ones, then we have a mix as well, which I'll talk about, but the first one is a CAM or C-A-M. So CAM impingement occurs due to an abnormal shape of the proximal femur. Essentially, a CAM impingement is a aspherical femoral head that results from excess bone formation at the head and neck junction of the femur. And specifically there, we will see a widening. So if you look on your screen, you can kind of see here. The CAM lesion, you can see how wide this is. This is just super wide. This is what we call that CAM lesion. So really wide, thick kind of femoral head neck junction, much wider than normal. That's going to be our typical CAM one. And a lot of times the most common movements that are restricted in CAM lesions include flexion, internal rotation, and adduction of the hip. On the other side, we have the pincer abnormality. So pincer impingement results from excess bone formation of the acid tablet rim, and this extra bone can lead to impingement of the labrum potentially as well. And as you can see on the pictures here, the acid tablet here, we kind of have a little more overarching here and leading to some clipping as well, and kind of see some bone spurs and whatnot, but this is essentially pincer. What you can see here, pincer, you see how this is not nearly as wide. When you compare the CAM, you can just see why that's wider, whereas here, kind of normal one, but it goes much deeper here. You can see this head right here, we have much more overlap here. We have much more bone exposed here, whereas here, just got a little bit left over there, meaning we have overlap of that acid tablet, and that's the pincer. You know, you kind of think about pincers like a lobster, that's what we think about there. So you can have CAM or pincer, and you can also have mixed. So where you have a pincer and CAM, and those people just got bad luck, 'cause that's a really, really challenging one. And so what are the symptoms of all this? Well, usually the first thing's first is this insidious onset, right? This is a non-traumatic injury. If someone comes in and says, hey, I have sudden onset hip pain, it's probably not an FAI. But pain is the most common symptom in an FAI, which typically presents in the anterior hip or the groin, but may also radiate to the lateral hip, buttock, thigh, lower back, or potentially knee. So kind of all over the place, but typically, if you have to pick, it's gonna be that anterior groin or hip. The pain is also described as intermittent and aggravated by activities such as prolonged exercise, maybe running, pivoting, moving side to side, shifting, sitting for extended periods, or things involving hip flexion like squatting and lunges. People say that all the time. Deep squats really bother them. Other symptoms they may have is either clicking, catching, locking stiffness, and potentially limited range of motion, specifically in internal range of motion. And how do we actually diagnose this? Well, diagnosis actually needs a couple components. So you need to have symptoms like we just talked about. We will have some exam findings, which we'll talk about, and then imaging. So this is not just a clinical diagnosis of, oh, hey, listen to their history. It's we're gonna listen to their history, get imaging, do a physical exam, kind of all three of those together can make the diagnosis. And so now let's move on to imaging. I mentioned it. We are gonna always start with x-rays, right? X-rays are kind of our first line. They're cheap and they're very reliable. We use these very frequently for FAI. A lot of times when you get these, the big main views you're gonna get are the AP view, so anterior posterior, and then the done 45 degree view. The AP of the pelvis and of the hip is used to kind of assess the hip joint space, right? Specifically looking for any sort of loss of hip space. The reason we're looking for that is 'cause if you have an articular space of two millimeters or less, that's indicating some potential arthritis, and that has been correlated with advanced OA and poor clinical results with hip arthroscopy, which kind of we're jumping the gun here. But if you're thinking about doing a hip surgery in CAM, it's really important to know, is there underlying osteoarthritis? 'Cause that may change your treatment algorithm. But that's what we're looking for specifically that AP view. Then we have something called the done view. So the done view is the preferred view for identifying CAM morphology. And in here, it's kind of an abnormal setup. Like, you know, what you're gonna do specifically is, you know, in your extra order, say, "Hey, worried about hip impingement?" We're like a CAM view. That's what you'll say. But what they're doing that is the patients can be in line supine with their pelvis in neutral rotation. Then they're gonna have their hip flexed to 90, and then they're gonna AB duct 20 degrees while the pelvis remains in neutral position. So it's kind of provides this little offset, gives us a really good view of that femoral head and neck, and kind of looking for any sort of CAM morphology. And so the next thing I wanna talk about is I mentioned these done views. Like, well, what's the big thing about done view? Well, done views give us a good view, but also we can help calculate the alpha angle from this. And CAM impingement is actually defined by measuring the alpha angle on X-ray. It has to be either in this done view or on MRI. And experts suggest that an alpha angle greater than 60 degrees should be used as a criterion for diagnosing a CAM lesion. So about 60 degrees is kind of where you go. And how do you calculate this? Well, there's kind of a whole thing here. So let's walk you through what it looks like. Specifically, first you draw a circle around the borders of the femoral head. So this is, you know, a perfect circle would be ideal, but if you go over here and look at the femoral head, you draw this circle, that is your circle. So first thing you do, get a circle there. Next, you draw a line from the center of the circle distally through the middle of the femoral neck. And this line represents the axis of the femoral neck. So we have this here, that is what this line right here, this straight down the center of the femoral neck, that is what we're looking at. Then you draw a second line from the center of the circle to the location where the femoral head exits the circle anteriorly. And this is the point where the femoral head loses its spherical shape. And so what we're looking at here is, you can see this is the circle we drew. This is the first line. Now the second line is going through right to the area here where we kind of starts to leave anterior and kind of lose its spherical approach and appearance. And that is where we're gonna be, that's gonna be our second angle. And then the angle between the two lines is the alpha angle. As you can see here, it's nicely labeled alpha. We're not gonna worry about beta too much here. We're just gonna do alpha, but you can see going down the femoral neck here to this other angle, this is our alpha. So in A here, this is a normal one on this side. The first one start normal. And then we talked about greater than 60, right? That means if we're gonna have a bigger angle, if you can move down here, this alpha is a bigger one. So a wider one, as you can see, the angle is much greater. And you can kind of see how just the femoral neck is shaped differently. That's what's happening from the cam. The cam is kind of leading to that offset being found earlier up here. So that's making the angle bigger and that's generally what's going on. So the wider board and the femoral head, it's gonna result in greater angle. And then from there, we can kind of make the diagnosis potentially. So that's one thing we're looking at in x-rays. And so that is looking for cam specifically, but there is some x-ray findings we can use to look for our pincer. And that is specifically the lateral center edge angle or the LCEA. And the LCEA greater than 40 degrees is a diagnostic criteria used to classify pincer diagnosis. And this is done on the AAP radiographs. And so how do we do it? Well, first we draw a vertical line that extends upward from the center of the femoral head. And this line represents the central axis of femoral head. So once again, we're kind of walking through here. Femoral head here, go straight up. That's what we're looking for right there. We got straight one. And then same thing here on this other left side. You go straight up through that femoral head. That's our first line. So vertical line extends right through the center of the femoral head. Then draw another line from the center of the femoral head to the bordering acetabular rim that's covering the femoral head. And this line extends to the lateral edge of the acetabulum. And you can see this here, we kind of have the other one not going to the lateral edge of the acetabulum, same thing there. And the angle between these two is the LCEA. And as we mentioned, LCEA greater than 40 degrees is diagnostic. So looking on these ones here, neither of them are necessarily diagnostic, but this is the angle that you look for. That is what you would do. And so that is why X-rays are crucial to start for diagnosis of FAI, 'cause it kind of sees the pincer and the cam, and those are kind of the specific things we're looking for when we're ordering imaging. Now let's move on to the physical exam. And as I mentioned before, this is only a part of the exam. It must be used with history and imaging as well to make the formal diagnosis. Specifically, when you start with range of motion testing, which is a part of everyone's tests for physical exam on anything that's just skeletal, you might see some decreased internal range of motion. Specifically, that hip internal range of motion is probably we're gonna see that. A lot of times you're gonna flex them in the hips at 90 degrees, and then evaluate the amount of internal external range of motion. And a common finding in FAI is decreased internal range of motion. Another test you can do that is very good is the FADIR, F-A-D-I-R. And when I mean very good, I mean it's highly sensitive. So it's a great screening tool. Meaning if it's positive, good chance that there's something intra-articular going on. But if it's negative, we're essentially ruling out intra-articular pathology. So this doesn't necessarily say, "Hey, if you have a positive failure that you automate the FAI." That's saying, "No, you probably have something intra-articular." Then you use other things like signs of symptoms and imaging to kind of figure out. But there's other stuff that could be positive as well. Another test that's commonly used is the FABER, F-A-B-E-R. It's debated its usefulness here. There's no definitive definition of actually what a positive FABER test is. Sometimes people say, "Oh, like pain, recreating their pain is a positive." And other people say, "It has to be a specific amount of lift up off of the table." And it's kind of nebulous, but it may be something where it recreates symptoms so we can use it as well. And then another test we can do is called the internal rotation overpressure test. This is where you're supine with your hip flex and you're applying internal rotation of the hip while maintaining axial compression of the hip. And pain inside this, once again, it's very nonspecific to FAI, but maybe more intra-articular. So you could have FAI, you could have maybe labral pathology as well. And another test we can use is the SCOWER test where the patient is supine with the hip flex, applying axial compression of the hip while abducting and adducting the hip, starting with the leg. And once again, all we're looking at here is these are all intra-articular tests, right? So we're just saying, "Hey, intra-articular, this does not necessarily help you differentiate. Is this labrum? Is this FAI?" You're saying, "Hey, is this inside there?" And then we use our other clinical context to kind of put it all together. And then another simple test. So I say those things, you know, those are all fancy and those are perfect, but like for primary care, realistically, if you do like the FADIR and then you can have them try to squat. Obviously, if this is like a 78 year old patient who's never squatting in life, please don't squat them. Like that's not it. But this is not the person we're looking for, right? In 78, it's gonna be a younger person. Specifically, that's usually what we're seeing in the history. But if they can squat, like have them squat, see if they can recreate that pain. A lot of times they have a squat and a painful squat in the anterior part of the groin. You think about, "Hey, could we be having some hip impingement going on there as well?" And so overall, there are a couple of tests, multiple tests. If I had to break it down into the easiest and best things to do, check that range of motion, see if that's decreased, do a FADIR. That's a really good interarticular test. And then you can also have them squat. And right there, we have a really good clinical context of what's going on. Now moving on to the treatment. The treatment at FAI can be very challenging. This is not a very straightforward one where it's like, "Hey, this is gonna work for everybody." And it can be very challenging. Usually we always start conservative first. That's really it, right? Physical therapy is our first line. Usually it really needs to be a custom approach, but activity modification is really the cornerstone of this. Things that people will focus on as well in physical therapy, maybe hip and core strengthening, maybe manual therapy, but lifestyle education, once again, is a big thing we talk about too. And when I mean lifestyle changes, a lot of times what people say is, "Hey, when I squat, when I do these X, Y, and Z things, when I, whatever happens, it really hurts a lot. I wanna get back to that." It might be one of those things where we may never get back to fully the amount of depth we can get on a squat or something like that. Maybe have to limit deep squats or positions like deep flexion or sitting in low chairs. All those things may continue to aggravate it. And so we may have to adapt things. And this is a really, really challenging conversation I have with patients all the time, is that, hey, how do we reframe things? 'Cause some people are like, "Hey, this is how I work out. This is what I'm gonna do." And if they want to, there are options that we can maybe get them back there and try. And sometimes PT is effective to get you back there all the way, but other times it may just take tweaking exercises you choose to do or range of motion or lots of things. So there's lots of things we can try, but always start with PT. And I really, for this one, I usually say get in person. I think that's really helpful to work with a physical therapist 'cause one case of FAI is gonna be one case of FAI and people may have different things that work for them. And so I kind of work with the patients and say, "Hey, this one I want you to see in person rather than necessarily rehabbing at home." Just 'cause getting any professional opinion is usually helpful for that. Moving on to injections. Injections, there's no real great long-term data that it does anything lasting. We have multiple injectates we can use. Usually though, where the role for injections is is that we're using it to determine if a patient is a good candidate for surgery. So we usually will do these injections and if they get good improvement from that, we say, "Hey, you may actually benefit from a surgery," and that kind of takes us into surgery. And we're typically doing arthroscopy, right? So they're going in there with a hip scope and it corrects these bony abnormalities. Maybe they'll go in there and repair the labrum as well. And it seems to be pretty efficacious. One meta-analysis I looked at found that 87.7% of people return to sport. Another show that 91% return to the sport, but only 74% go back to their pre-injury level of participation. So that's something to talk about there. We know getting 85 to 90% of people back to sport, that's great, but only about three quarters of them back to their pre-participation or pre-injury level. So that's what I talk about when you have to think about considering altering your movements, right? We may not be able to get back to the exact things we could do and it shows in the data as well. Although those are pretty good numbers, right? And overall surgery may actually have improved outcomes at 12 months compared to conservative treatment as well. And so this is when we think about surgery potentially, you know, it's an option. Obviously surgery is a surgery and there's always risks to that, but it's what we think about it. Another reason we think about surgery potentially for this is that FAI does seem to be a risk factor for osteoarthritis later in life. And the only problem is, you know, theoretically, maybe if we change the anatomy that if we have some surgery to correct that anatomy, it may, or, you know, hopefully decrease the prevalence of OA later in life. We don't really know that yet. You know, we don't know if having surgery, you know, does prevent developing OA, so we don't just know that yet, but that's the theoretical idea behind it. And when we do have patients that we're thinking about for surgery, who are those patients, right? Who are the people that may benefit from this? Well, first of all, if someone has preexisting osteoarthritis, that's a strong predictor of a poor outcome and eventually probably just gonna need a total hip and the hip arthroscopy may not be the best. Obviously if they're a young athlete, you know, say they're in the military or something, they have a lot of life left, they gotta use that hip for and can't get a replacement, then maybe a short-term hip, you know, scope might be beneficial, but once again, it's gonna be very patient dependent. But if they do have lots of weight, it's usually a bad end in care that we're not gonna have great outcomes with just the hip scope. Other factors that, you know, lead to unfavorable outcomes include things like obesity, hip dysplasia, prolonged symptom duration, meaning it's gone on for a long time, and mental health concerns, meaning people are worried that, you know, their fear, a fear of re-injury, they have lots of stress and just lots of health stressors and mental health stressors going on, they might not be awesome candidates for this. All right, so now we're kind of laying in the plane here, just an overview of FAI. First of all, we are gonna diagnose this with symptoms, imaging, and a physical exam, kind of using all three to put together. The question is, hey, is this actually pathologic, the findings on X-ray? Well, we're not quite sure, right? We know we have X-rays of people who have this morphology, but don't have symptoms, and so it's much more than just, hey, on X-ray, that's why we use all three of those things. And from a imaging perspective, we wanna make sure that if we're ordering those, we wanna get that done view, so we can kind of get a good look to look for the CAM type lesion, and remembering that we do have CAM and Pinsir as the main ones. But really what I want you to take away here is that if a younger person comes in your clinic with anterior hip pain, right, pain with squatting or anything like that, always be thinking about this. Obviously, there's lots of other things I've talked about in other hip lectures, but things like we can't miss like stress fractures, but this is a different story. Usually this is, hey, I, you know, front of my hip pinches when I'm squatting, and I don't like it. That's what we think about. We think about that, get the imaging, kind of confirm it, and then treatment-wise, it's gonna be starting conservative, and then some candidates may do better with surgery. And this is a discussion with the patient and your orthopedic team and all that stuff. But when this comes in your clinic, I don't want you to say like, hey, this is nothing. You know, really work this up, get the X-ray, 'cause sometimes if we get an earlier approach to therapy or surgery, it leads to better outcomes. And so it's not an urgent, can't miss anything like that, but it's something that you will see. And if you're looking for it in clinic, if you haven't seen it yet, I guarantee you will because it's out there. And this includes the podcast. Thanks so much for stopping by, I really appreciate it. I hope you found today's episode helpful. And if you did, it'd mean the world to me if you left a five-star review on your podcast, platform, or choice, or if you share with a friend who you think may enjoy this. And if you never wanna miss a piece of content, consider signing up for my mailing list, which is linked in the description below. I'll just send out the content I release occasionally on the week, and I promise never spam you 'cause I hate spam just as much as you do. But that's it for today. So get off your phone, go be active, have a great rest of the day. We'll see you next time. Disclaimer, this podcast is for entertainment, education, and informational purposes only. The topics discussed should not solely be used to diagnose, treat, or prevent any condition. The information presented here was created with an evidence-based approach, but please keep in mind that science is always changing, and at the time of listing this, there may be some new data that makes this information incomplete or inaccurate. Always seek the advice of your personal physician or qualified healthcare provider for questions regarding any medical condition.
