So I appreciate the opportunity to talk. We'll kind of get through some of these things to speed up here guys. My disclosures are in the program. So what's the evidence when you're talking about borderline hip dysplasia? The too-long didn't read version is that it's currently inconclusive and you need better definitions of what is really a successful outcome for our surgeries and then it obviously requires further study. So we'll kind of dig into it a little bit. I think that we all know that there's a spectrum of hip morphology ranging from really deep hips to really shallow hips and it's really these ones in the middle where there's some confusion about what to do from a surgical technique. Traditional definitions of borderline dysplasia, I would throw out that we should probably throw out this term borderline dysplasia. We should probably talk more about instability versus stable hips. But traditionally lateral center edge angle between 20 and 25 and anterior center edge angle between 20 and 25 and a tonus angle between 9 to 15 degrees depending on who you're reading and whether or not acetabular retroversion contributes somewhat to this as well. So measurements that we make on x-rays, certainly we look at the lateral center edge angle. Under 20 is pretty clearly dysplastic though some people use 18 as the cutoff for what's considered to be borderline. Your acetabular inclination, I'd encourage you to learn how to do this. This is probably most predictive. Over 10 has been predicted to be about 70% of the time consistent with instability of the hip. So at our institution we use under 9 as normal, 9 to 12 is borderline and over 12 is dysplasia. But you'll see in some of the studies that we'll talk about they use over 15. We tend to use the extrusion index as a measure of posterior coverage. Looking at retroversion, some people have used an anterior and posterior wall index. About 27% of the head is normally uncovered posteriorly. And then the fear index from Martin Beck looking at the angle between the acetabular roof and the femoral growth plate is also something that you should understand how to do when you're dealing with these patients. The other thing that can be interesting to note in these patients is they have the pseudo cam deformity. They have kind of proximal flattening above the physis. So it's not really a cam deformity. It's kind of flat up above where you would normally see kind of more sphericity there and then a lack of offset down lower on the neck. So as we talk about instability versus impingement, they can both exist. And you can see in this patient there's a bony prominence there consistent with cam morphology but also a shallow socket. So this is the crux of what do you do with these patients. One of the things that you need to understand is the contribution of ligamentous instability. It is additive to their bony deficits. So in a patient that's incredibly stiff, that's kind of a muscular pelvis like a butterfly hockey goalie that has some dysplastic morphology of their socket, that may be a different patient than your 15-year-old ballet dancer who has got a Baden score of 9. So understanding how to calculate a Baden score is really important. So hip arthroscopy and dysplasia, why is it important? Because it's increasing in the amount that's done. The anchor group looked at the patients that required a PAO and they found about almost 200% increase scope rate in these patients in their population. And so it's a lot of people are putting the scope into these hips that are kind of borderline or dysplastic. So what does the data tell us? Well, almost every study that's been published in the sports side of the research tells us that you can see increased patient reported outcomes and patients can do well with arthroscopic treatment for borderline dysplasia. And so what seems to be most important? One of the things that people talk about is a capsular plication. That seems to be most consistent in all the studies that are done. There's a lot of different ways to plicate the capsule. At our institution, we tend to use a horizontal mattress configuration. You can see that going in here. So we go through the distal leaflet, retrieve from the proximal leaflet, pull out to get some length, go back through the proximal leaflet, and then retrieve through the distal leaflet again. And this allows you to kind of have a nice plication and you can really dial it in. People have used simple sutures. They've used figure of eights. Ben Dome has talked about kind of a shift, a capsular shift. And all these things seem to be important in improving outcomes. So we'll kind of skip forward. So the big question is, are we doing as well as we think we are? This is a study by Shane who looked at borderline dysplastic athletes and their return to sport. And while he showed that about 75.6 percent were able to get back to sport, really only about 45 percent of those returned at the same level. And only 3 percent returned at above the level that they were at prior to having their issues develop with their hips. So that's about less than 50 percent are getting back to the level that they were at prior. So I think that while one of the things is that their PROs go up. This other study from 2019 showed that their modified Harris hip score improved by almost 20 points. And their NHAS score improved again by about 17 points. But about 40 percent of these patients said they were unsatisfied with the outcomes from their surgery. So we may be falsely deluding ourselves in thinking that they're doing better than they actually are. What are outcomes for, it's about a 13.7 percent reoperation rate in these patients. That's another kind of red flag for us, higher than what you would see in a standard hip arthroscopy. So can we predict failure? Ben's study shows us that patients over the age of 35 had worse outcomes. They are more likely to fail the surgery. Failure was defined as conversion to total hip or not making their pass score. Predictors of failure in most studies in terms of systematic reviews and meta-analyses include excessive femoral antitorsion, ligament of teres tear, older age, severe dysplasia, osteoarthritis. And then the other thing that you can look at is this fear index. So if their fear index is greater than four degrees, that would seem to be a predictor that the hip was more unstable. And they may not do as well with an arthroscopic surgery. What about doing a PAO for these patients that they fail? The anchor group looked at that. They showed that their pre-op scores were worse in the patients that had a previous arthroscopy, and their post-op scores after a PAO were worse. So you may only get one chance to do it well. What about doing a PAO for borderline dysplasia alone? There's been some studies that show that you can get similar outcomes to what you can get with arthroscopic surgery, but there are major complications between nine to twenty percent with the PAO. So it's not really an operation to be used lightly, and that's something to give consideration in these patients. And they saw a 27% risk of needing another surgery in the form of an arthroscopy, and one of the main issues in their studies was if they had a borderline hip. So even a PAO in isolation may not be the right answer for these patients. So final thoughts. I think this may scream for a combined approach of both an arthroscopic and an open procedure. Ligamentous laxity is additive and needs to be considered. Lateral center edge angle is insufficient as the only measurement. So if you only say eye scope anything over 18 degrees, that's probably not a great idea. Is there a place for isolated arthroscopy? Certainly there is, and if you're going to do an isolated arthroscopy, I think using a plication as part of that treatment algorithm is necessary, and more study is needed for these patients. So thank you for your attention.

borderline hip dysplasia

surgical treatments

instability versus stable hips

x-ray measurements

arthroscopic treatment