bit of the easier assignment compared to Mike, who's going to talk about hip instability in this population. So I'll take it. This is a common condition that all of us are learning more and more about in terms of FAI and the contact athlete. Again, I want my disclosure simply to thank all the colleagues, many of whom are in this room with all the various teams that are in the area of hip preservation that have contributed to this work and led to really good protocols at the combine, et cetera, in terms of getting imaging in the setting of lost internal rotation, symptomatic groin pain. That is really something new in the past five or ten years. The clinical problem of hip impingement is really evolved, again, lots of credit to the colleagues really across in Europe, Reinhold Gans, Michael Lunig, and others that first described hip impingement. It's now clearly in the literature been identified as the number one cause of osteoarthritis in the nondisplastic hip and reflects this regional loading and repetitive microtrauma that happens between proximal femoral dysmorphology, or the so-called CAM lesion, and either acetabular, focal, or global overcoverage. And quite simply, we've used these overly simplistic terms to describe them, the so-called CAM lesion or pincer lesion, or more commonly, both. But the concept here is that it's this mechanical deformity that then, of course, precipitates chondrolabral injury, which results in cartilage damage and arthritis, but also pain. And accordingly, I think probably one of the most important take-home points is while this often comes referred to us in this athletic population or otherwise as a labral tear, the labral tear is in many ways the smoke, and the underlying fire is this untreated deformity. And the literature has suggested that the number one indication for revision surgery is an inadequate treatment of this deformity, which would make sense. This is, I think, what's important to recognize, though, where some of the principles in the broad population don't necessarily apply directly to the elite athletic population, whether it be high-level Division I or elite football athletes in the NFL. These are some of the literature that's been published on the incidence and the prevalence of these deformities. You know, if you look at the study in JBJS by HAC, 14 to 53 percent incidence of a CAM deformity. Agricola abroad said 11 percent of HIPs, so relatively low numbers by comparison to what we see in this population. Frank and others in 2015 reported these numbers, an incidence of 37 percent of a CAM lesion, 67 percent of a pincer lesion in asymptomatic individuals pulled through a large systematic review. But then when you dig into the literature that is pertinent to our work in the athletic population, you see numbers like this. Chris Larson published, at least 90 percent of NFL athletes had one radiographic sign of FAI. Jeff Nepple and his group at Wash U in St. Louis said 94 percent had some level in symptomatic football athletes. And then some studies we've done in hockey report a similar incidence of CAM morphology. So clearly, this population self-selects for more of this challenge, likely reflecting some impact on the growing and developing proximal femoral physis at a young age. Now, this is also what's critical, is in general, most of the literature in FAI will focus on the quote, unquote, nonathlete. And of course, the focus there is joint preservation, right? If we treat this issue in the setting of pain, we'll maybe help to prevent the future hip replacement. But in the athletic population, there's a short-term consideration, just as Brian mentioned with hernia repair, is the idea of function and performance, just getting back to sport. So we have to balance their short-term goals with long-term goals in this population. Starting first with long-term goals, what is really the impetus behind treating these patients for symptomatic relief, but also long-term benefit? This is great work done by John Cloese at WashU, where he looked at patients who had a young total hip replacement, under the age of 50, which would suggest why. Why did they have this at a young age? And when they divided it out, there were some good reasons, like a group of them had avascular necrosis. A number of them had post-traumatic arthritis or inflammatory conditions like rheumatoid arthritis or lupus. But then there was these kind of, quote-unquote, unclassified categories, namely, quote-unquote, OA, and then this smaller group of unknowns. And when you start digging into those radiographically, as John did, you find that the vast majority of these, in fact, come down to FAI or some variant of FAI-type deformity, like a slipped epiphysis. And so then when you put the numerator of either dysplasia or impingement over that denominator of, quote-unquote, idiopathic OA, you would argue that 90% of those hips weren't idiopathic at all. They either had dysplasia or impingement, and that was the reason for the premature arthritis. So, of course, for those of us that are in this field, the exciting concept is that if we treat these patients early, maybe this is something that we can use to prevent the future hip replacement. In the near term, though, we don't have that data to rely on that, in fact, our surgery changes natural history. So instead, we need to think about the athlete in the near term. So what's that look like? If a patient has FAI, they have decreased range of motion, restricted internal rotation. That leads to functional range of motion limitation in sport. If it's a cutting and pivoting sport or a contact sport like football, that can lead to chondrolabral injury. That leads to pain and decreased performance, and then that's finally where it presents to us with pain or inability to play. And so that's your near-term conversation of what's the immediate benefit with unknown long-term benefit. What's our data suggest? In this group, we have more data here, which is improved kinematics have been shown, significant improvement in patient-reported outcomes, like the modified Harris Hip Score or Hip Outcome Instrument, and somewhere between 73% to 96% return to play in general. Now again, the devil is in the details, and there's more and more literature trying to look into who does better and what may do better than others. And probably all the culprits, you may think, are factors here. The age of the patient, sometimes a surrogate for occult arthritis, the nature of the deformity both in terms of size and morphology, and then of course the sport and the years of play in the position, and then the additional questions about our surgical intervention. Did we close the capsule or not? Did we repair the labrum? Did we address cartilage pathology? So just a little bit shared there about the literature here to come. I'm not going to go over this slide too much because Mike will cover this nicely in the next talk, but this hip impingement category tends to fall more in this dynamic side of this equation. The cam and pincer are dynamic conflicts at end ranges of motion, but remember, it's a continuum. And so hip instability sits on that more static side where there's undercoverage and associated anaversion or valgus, and that can lead to associated issues. So what is the literature that we have here in this sport-specific analysis? This is good work done from Daniel Nawabi, a colleague at Special Surgery, where he looked at, with Brian Kelly, over 600 athletes that had been treated for FAI in Brian's practice, and they divided these into high-level and recreational athletes. And when you look across the board, they functionally found six categories. There was the so-called rotational endurance or running sports, the flexible sports, contact sports, asymmetric overhead sports, and endurance sports. And in general, we found slightly different morphologies and presenting symptoms in these different populations. When you divide it out, what things can you find here? Across the board, general tendency for FAI more common in male than female, interestingly a little more common in the right hip than the left hip, and an interesting predisposition more common in males than females to have this bilaterally. But I'll draw your attention to the fact that for the conference that we're here for today, football, it's a very high prevalence. It's the number three sport across the board, second only to soccer and hockey, and in male athletes, it's the number one presenting sport. So it is something that you will see more commonly on radiographs than not in the football population. So the conclusion from Danielle's study, very common in these sports, more common at end range of motion, endurance athletes were significantly younger than athletes in impingement sports, may be reflecting the fact that it presents to us in these impinging sports only after there's some chondrolabral injury that induces pain. Well, what are the outcomes? What do we know about treating this arthroscopically? Again, Mark Philippon, one of the pioneers, initially reported this across a number of professional athletes, not just football, in fact, just 11% in this series, but reported fairly good outcomes of 93% return to play in reasonable, well-preserved hips. In hockey, also a fairly good track record. This series from Mark Philippon reported a delta in the modified Harris hip of 25 points, and the mean time of return to play a little earlier in hockey, closer to four months. When you look at a mixed group, again, this is Shane Noh's series out of Chicago, similar delta in improvement across anything from high school to professional sports for mixed-type FAI, 73% were still doing reasonably well at two years follow-up. Again, Thomas Bird and Kay Jones have reported on longer-term follow-up in their patients, over 200 athletes, similar deltas of improvement and fairly similar rates of return to play, which are favorable, 85% to 95% after hip arthroscopy. But I'd like to take a little bit of a deeper dive here in focusing on football. This is a paper I had the pleasure of doing with Brian, focusing on 40 professional NFL players in 48 hips. The mean age of these athletes was 25. At the time, the vast majority of these were in the New York football giants during my time in fellowship. 94% of them, I was presenting complaint, no surprise, was with deep terminal flexion. They complained of pain with sitting and with squatting. Interestingly, pertinent to Brian's presentation just a few minutes ago, 20% of them had already had previous, quote-unquote, sports hernia surgery. When we looked at their mechanisms, 31 of them were non-traumatic, 17 of them were acute but non-traumatic, and seven indicated a recent traumatic episode of FAI-induced instability. When we looked at position, interestingly, relative to the line of scrimmage, this is actually what we found. The predominance of FAI presented in two categories, offensive linemen and actually defensive skill players. 75% in particular were in these populations. The reason for that's not entirely clear, but there's some theories perhaps about some of the stance requirements of all linemen that may contribute to that. We found, interestingly, that the restricted internal rotation was the most sensitive exam finding, and IRF, or internal rotation inflection of less than 15 degrees, was a good marker for occult impingement. And that has led to changes in protocols to get x-rays when IRF is less than 15 degrees. For morphology, CAM lesions, again, most typically at a one o'clock type of location with a mean alpha angle of 70 degrees, and again, relatively normal version across the population. When we looked at chondrolabral injury for those that were treated, fairly concordant with what we see in male contact athletes, anterosupir labral pathology, chondrolabral peel and CAM delamination, somewhere between the 1230 to 130 location where you would expect it. And again, these typical findings where we check fluoroscopic corrections to make sure that we've gotten those corrections in all planes in those athletes. So again, summary here, in this population specific to football, we had a 93% return to play at six months. Again, in terms of performance, we noted no significant decline in their first post-surgical season, so they seem to perform relatively well compared to other athletes. Finally, I'll finish up on what literature and research that we hope to do in the future of why this predisposition to O-linemen and defensive skill players. No one quite knows, but I think all of us would agree that at least in the O-line population, this is a significant requirement for their stance and position. We did some preliminary work actually with Ronnie and Lee and the group with the Giants at the time. You can see, you can do some general measurements to look at differences in these athletes with those who have FAI and those who don't, and you can see some restricted hip flexion in that population across the board. So this is something we need to understand better. Does this develop at a young age in these elite athletes who of course have started playing at a young age, and can we use a loss of hip flexion or pain with squatting as a screening tool to identify a prognostic risk for future FAI and surgery? So in summary, high rate of return to play in the NFL after FAI corrective surgery. It has a high prevalence and incidence in this population. O-linemen are uniquely affected, but further studies are needed to understand why in that population. Thank you.

hip instability

athletic populations

femoroacetabular impingement

arthroscopic hip surgery

NFL athletes