All right, Ben, first question to you then. All the papers that you showed, single center, single surgeon, five-year data, does that concern you, that these patients in the longer term, in 10 years' time, are actually going to have an arthroplasty and you may have made the wrong decision? Well, so first of all, to the contrary about evidence, I think it is very hard to extrapolate evidence from one institution to another institution, given that none of us really do things the exact same way as anybody else. So I think we can run into a big pitfall when we look at evidence from another institution and try to apply it to our own, and the best way to prognosticate our own patients is based on our own data in each of our centers. So I do rely heavily on data that we collect at our center. In terms of am I concerned that the patient will have an arthroplasty in 10 years' time, Absolutely, that's the core of the question. Shared decision-making is a concept that has grown in recognition over the last five or ten years, and I think this is a really perfect case for shared decision-making to take the front seat. We want to explain to the patient what we know and what we don't know and what our evidence is and really allow them to be part of the decision-making, because it is a tweener. Let me turn to you, does economics play a role here? Your system is obviously similar to ours. In the UK they look at interventions, if they're not going to survive for 10 years they are probably bad interventions. Is Canada the same, and does that play a role in your decision-making? If you're not able to take that hypotheroscopy on for 10 years as a positive outcome, then are you therefore considering an arthroplasty, and does that actually play a role in your decision-making? Yeah, it does actually. We did a study years ago. I think those numbers are good, but in every society it's very, very different. So we had a time trade-off method looking at preference for an operation and duration of it. So we say at six months if you had a scope, would you accept it for hyperarthritis, and most people would say no, I would not take a scope. Then at 10 years, most said yes. Then went to 9.6 years, or 9.5 years, yes, and then a year, yes, then 1.5, and then 8.5. So we started looking at one number, when you start taking six-month chunks out of time from that patient, would they say yes to the procedure? And in Canada the number was 4.6 years. So if you can get 4.6 years of survivorship or improved quality of life, patients were absolutely accepting of conversion to arthroplasty. But then in the United States and Europe it would be a different number. So generally, if we tell the patients in that discussion, if we can get you five years, would you accept this? And they say yes, we'd consider it. And then, Ben, to you, does gender make a difference in your decision-making? And secondly, what radiographic predictors are you looking at, and in which patients you definitely won't offer them an arthroscopy and consider an arthroplasty? I think there are – the short answer is gender by itself probably does not make a decision for us. However, there are certain things that are more common in men and certain things that are more common in women. And so, for example, big CAM-type impingement, more common in men, instability more common in females, although each gender can have the opposite. So in this case, this is a very, let's say, masculine hip. It's a stiff CAM-type impingement type of hip. The factors we're looking at from a prognostic standpoint, we've created a model based on 34 different variables, so I won't name them all, but without doing a mathematical model, in this case, looking at age, joint space, clearly we talked about the subchondral changes, which are there on the MRI. We see edema, we see cystic change, but that edema and cystic change was right at the periphery of the acetabulum. So in my mind, if we're doing a femoroplasty, we're unloading that to a degree, and it probably does need a microfracture if there's full thickness cartilage damage there, but it's got a shot, a real shot, because we've changed the mechanics in a favorable way. So if there were joint space narrowing, if there were central cartilage loss, if there were bipolar cartilage loss, if there were bigger subchondral cysts, any of those things, or if the patient were older, any of those things would push me toward arthroplasty. Okay. Last question to you, Femi, before we go on to Chris for any questions, and then the voting. The registry data that we have from the UK, and we've recently published over 5,500 of these patients, only two-thirds are actually achieving their MCID, and that's the real-world data, and then you see centers like from Ben and results from Ben, and you get fantastic results. What are your thoughts on that? I'm obviously not getting Ben to answer that. No, I mean, part of the problem, or sorry, I would say the problem, the challenge with orthopedics in the way of hip arthroscopy is a significant expertise bias, which is the world's best surgeons, including Ben Dome, Mark Philippon, Brian Kelly, are producing their results because they are the best in the business. And then when you broaden that category to have a registry where you have a variety of expertise involved, then you can expect results not to match those of the experts. So I think explaining that and looking at why you have a disparity in data is look at the authors and the authorship group and where the data is coming from, and if it's from Ben's center, well, you can't expect somebody who's in first-year practice may not have a fellowship to equate with his numbers, right? So really look at that expertise bias, and I think that explains a lot of it. Cool. Chris, any questions from you? Yeah, I think the only thing I would bring up is I think occasionally we'll have a plain radiograph that shows a well-maintained joint space, and then we'll get the MRI, and things start to look ugly. So if you guys could just comment on is there something on the MRI with an x-ray that has a well-maintained joint space that you would see and you would say, I'm not going there. What should we look out for? When should we put on the brakes? Yeah, that's the heart of the question, and in this case I really would see it as a tweener and I really would have had a shared decision-making type of conversation with this patient because I think you could make an argument in either direction, but so in other words, I didn't see anything in this case that is to me an absolute contraindication to arthroscopy, but things that would be, again, bipolar, chondral loss, big subchondral cysts, especially cysts or edema in the weight-bearing central areas, those would be things that would steer me away on MRI. Brilliant. So let's bring the voting up and let's see whether the audience is definitely aiming for an A star and whether they believe in evidence-based medicine, or are they going with Ben's results? Tell us what. Okay, so Ben it is then, right? I just want to point out something. So at our institution at UCSF, Kevin Bozic, our past president of the academy, published a paper which many people have never read, but it's a really good paper, and the paper was on the cost-benefit ratio in the United States of hip arthroscopy versus just letting people wait for their hip replacement, and he's an arthroplasty surgeon, by the way, and he and Frank Valone, who was one of our ex-residents, came up with statistics which Femi would understand and I would never understand, but it's 16 years. So in the United States, if you can get 16 years out of a hip arthroscopy for any reason, the cost-benefit ratio is favoring hip arthroscopy. So anecdotally, we've all had, I mean, I've had a lot of experience with doing degenerative hips, and I think we've saved a lot of hips, but that's only anecdotal. It's not based on evidence, but I just want to compliment all the speakers. Thank you very much. Words of wisdom. Thank you. Okay, so well done, Ben.

hip arthroscopy

hip arthroplasty

evidence-based decision-making

patient involvement

cost-benefit analysis