I want to thank all of the speakers for giving great talks and really a lot of information and staying on time so we have some time for questions. Yeah, this is for Jeff actually. You didn't talk about it until the very end about the site of your bowel distraction, the femoral proximal tibia. So us old guys were always taught that the reason why you want to fever is because of the obliquity of the joint. So that's why we stayed away from doing tibial ideology, especially lateral opening with tibial ideology. And so many of these patients, like your case in New York, showed that's beautiful. There's also a little bit of lateral promocondylar hypoplasia, as you showed in one of your slides. So would you comment? Because when you mentioned, you can see that it was the size of the crick that drove what you did on the tibia or the femur. What about the obliquity of the joint on your weight-bearing film? So the obliquity after you do the correction? No, three hours. Yeah. There's a couple that you showed with an oblique joint. In advance. Yeah, and I think that with a lot of valgus of the knee is secondary to hypoplastic lateral femoral condyle. And so I think that if that is the ultimate source of the valgus, then I think correcting it on the femoral side where the deformity is would be a good choice. So I think that would be an indication for a femoral-sided correction. For on tibial corrections, it is one of the limitations, though, on why we don't want to do it for large corrections, and why there probably is a limit, because you may instill that joint line obliquity. And in the past, those patients have been shown to have worse outcomes. I think that's a great question, and Jeff, that's a great answer. I was trained to do osteotomy looking at a mechanical axis method, and most of the time it was, well, yeah, if it's valgus, you're going to treat it in the distal femur, varus, and the proximal tibia. And certainly the Europeans are really pushing this idea of doing deformity planning and measuring out your articular angles, both in the distal femur, proximal tibia, understanding rotation, and then planning your correction based on where the deformity is. And so, yes, maybe 85%, 90% of the time in a valgus knee it's going to be a distal femoral correction, but a lot of the time it's not. Very occasionally it's going to be a bilateral deformity. And where we're seeing more and more in the varus knee is distal femoral vera as well as proximal tibia vera and doing double-level osteotomies to maintain your joint line obliquity. So I think the long and short of it is do your deformity planning and correct where the deformity is. Al, can I make a comment? Sure. So I think for myself and for our fellows, it's been quite useful to use some of the newer tools, some of the patient-specific systems, which are CT-based, and we can actually look at all the angles Al just described and look at the joint obliquity and model out pre and post and choose femur versus tibia. I think what I've found on that early adventure is that I am starting to do some smaller corrections, particularly for athletic patients who are flexion loaders who have posterior lateral defects and or meniscus deficiency from prior ACLs. And so it's just a new tool in my relative toolbox, and I'm wondering if, Al, you do that, I think, for some as well. Yeah, we do. I mean, we do do proximal tibial corrections. A lot of times the proximal tibial corrections for valgus is because it's an interarticular deformity. You're treating the meniscus articular cartilage loss, and they're often collapsing in valgus, and that's why we published that paper of lateral opening wedge proximal tibial osteotomy. And interestingly, historically, the old Coventry paper, which looked at the distal femoral osteotomies, it was kind of a throwaway comment of if you had to correct more than 12 degrees, then you should probably go to the distal femur rather than the proximal tibia. It's not really based on really good, solid clinical evidence, but certainly deformity planning and correcting where the deformity lies is the way to go. Question here. For sure, Robbie, do you want to take that? So lateral laxity, maybe go in with it. Yeah, so I think when you're doing your templating, make sure your x-rays are good. I've seen Dr. Critch's x-ray where he has this huge 20-degree varus knee, and he got him to stand straight, and it's neutral. So make sure your x-rays are good. And what I do, if it's an asymmetric gap on the lateral compartment, I subtract one millimeter or one degree for every millimeter of asymmetry on that x-ray. So I will reduce it, and I always check, in cases like this especially, I always check in the OR with the alignment rod. I know they're not perfect, but I want to make sure I'm not overcooking it. Or if it is a ligamentous problem, are you needing to add a post-lateral corner or isolated LCL reconstruction in addition? Look, and the other thing you need to take into account is you have to look at your patient. You see the long cassette, and here's the patient, and it doesn't add up. You have to repeat the image, or better, get three-dimensional imaging. You've got to get CT scan. There are so many cases that we can show you. You have a 2-degree vargus on one long cassette and a 13-degree on the other cassette. So you can't really do your planning off that. So like Seth said, you've got to get CT scan in that case. Follow-up to that, we are living in the digital age, and there are proprietary deformity correction tools out there where you can measure joint line congruence angle. You can assess those. You can do the osteotomies on that system and work out just how much correction you need to address the soft tissue deformity. So it's all there for you. I don't. Anybody? I wanted to make a comment about overcorrecting on the femur because we talk about joint line obliquity, which is, of course, important, but regardless of where you're going, you can't, you know, we tend to like to put a varus knee maybe into a little bit of valgus, but you don't want to put a valgus femur into a varus femur because if you have a varus femur, you're going to have to abduct your hip in order to get your foot pointing forward. So if you have to overcorrect it to the point that you create a varus femur, then you have to do a two-level osteotomy, femur and tibia. I've got a couple of questions here in the app. Very quickly to Volker, are you taking into consideration lateral extra-articular reconstruction in your decision-making when looking at slope? You said quick question. Well, certainly, right? So like I said in the talk, you have to look at all the different factors. If you're asking me, am I doing a lateral tenodesis with a revision ACL and an osteotomy and a meniscus transplant? No, it's either or. I haven't done that. I have combined meniscus transplant with osteotomy, but I haven't combined lateral tenodesis with meniscus transplant or osteotomy. Why? You know, it's the lateral procedure. If you think about it, you're not tensioning anything over there just to reduce your stress fluoro. That's not what's happening, right? It's a little bit like a check grain, like an MPFL. And we showed this in a study that was recently published in AJSM. In the first six months, that lateral tenodesis was really tight. It produced a more posterior translation on the tibia, four millimeters. That's enormous. I was shocked when I saw this data. After 12 months, it's all evened out, whether this thing stretched out or the patient just got more active, whatever it was. Over time, you're not going to over-reduce something with that lateral procedure. You just add this if nothing else is available to you. That's my two cents. Go for it. In what direction is your osteotomy going to start? How much are you going to stretch? So double level, vulgar? So a vulgar, that's nine degrees. Your goal would be to go neutral. I would not go and varisate. You shall not varis. But for a varis knee, it depends on arthritis or ligaments. For a varis knee, it depends. If it is primary bilateral ten-degree varis, and the patient is fully aware, and you just told them, we're going to do a bilateral surgery. Once you like one side, we go to the other side, you should probably over-correct a little bit. In Europe, they go to 62%, and in Asia, too. I've had not very happy patients when I over-correct them. I just have not. If you're doing an osteotomy with an ACL, do not over-correct. Just don't, because they don't even know they have a varis. You know it. They don't really know it. So you just go to neutral. Unload that compactness. I just want to make a comment on the previous question. I use tibial slope in primary ACLs in some revisions kind of as a modifiable risk factor, meaning if it's there, I might add something extra to my ACL, and that might be an LET if I don't have obvious meniscus problems or bad tunnel position or poor graft choice. So I think I use trochlear dysplasia in the same way as a modifiable risk factor, meaning I'm not attacking the dysplasia often, but if it's there, and it often is, then I'm potentially thinking about whether to add more to my MPFL. So those two things in the back of my mind, I think about and measure every time, and I use in my decision-making of soft tissue versus bone. Any more questions? Yeah, over here. I'll make one comment, and the most important thing that I can tell you is if you see someone with open growth plates or all sports medicine physicians, many of us don't do guided growth, but please think about guided growth, and that is missed so often. You're trying to follow a valgus knee. We're not sending them to the right people because it's not in most of our toolbox. So genu-valgum, I have a pretty quick referral to a pediatric orthopedic surgeon and let them figure it out, but the answer we don't know, and Al and I were kind of looking at it, but I would say that most people, if you have a lateral compartment at risk, yes, of course. Lateral meniscus tear, maybe an OCD, early cartilage wear. That is not so hard. Everything else being equal, most people feel when the weight-bearing line passes through the 50%, you know, more than half of the lateral compartment, then you might start to do corrective osteotomy. Based on the osteotomy of the tibiofemoral joint, maybe not so much tibiofemoral. I'm sorry, maybe not so much for patella instability. However, it does appear in our early studies that are becoming quite large, that far more patella-femoral instability exists in valgus knees than varus knees. In our population of over 200, we had four varus knees. The highest varus was four degrees of varus on weight-bearing lines. Everybody else was valgus, and if you looked at greater than four degrees of valgus, there was approximately 60 people were valgus knees. So there's something to it. We just don't quite know when to correct it. It's one more modifiable risk factor, and you can't correct everybody based on x-rays back to what you think is the perfect anatomy. Don't forget about rotational malalignment. So I think hopefully you're getting the message here is that you've got to assess the patient, you've got to do deformity planning, work out where all the deformities are. The tough thing right now is working out when to address some of the minor deformities. I'll just add the athlete I showed you was asymmetric valgus. I tend to put a lot more stock into asymmetry and also had that lateral treatable defect, so it pushed me in that direction. I think there are other kids who are skeletally mature who have tremendous deformities and valgus rotation and a very lateralized tubercle, and I think there's no way I'm going to be able to do my soft tissue releases and get that patella balanced without considering a tubercle osteotomy in that kind of patient. So I think it varies, but they're different players in my mind. Seth, would you consider tubercle osteotomy when they go back to Stanford football? Well, we had one that I didn't do last year, and he went back to play, but rarely, I guess, would be my short answer, although of all the osteotomies, people are doing TTOs in these high school kids, and they're healing, and they're getting back to the highest level of sports. So I think just because we're not doing it doesn't mean that's right. It just means it's not common, and it's not always popular. I think we could spend another half an hour, 40 minutes, talking about return to sport after osteotomy. We're a little bit over time, so I want to let everyone get to the exhibition hall and support our sponsors. I'd just like to thank you all for attending. Thank Issacost for co-sponsoring this particular event. Thank you very much to the panelists, and don't forget about the Issacost meeting in November this year, so Cape Town, South Africa, November, December 27th to the 1st. So thank you very much for your attention, and enjoy the rest of your meeting. Thank you. Liza? Thank you all. Let's get a picture, guys.

osteotomy

knee deformity correction

deformity planning

patient-specific systems

CT scans