We'll spend the next, you know, 10 minutes or so talking about getting it right and avoiding complications in HTO. My disclosures are online. I think for us, you know, we've known for years that osteotomy has been an international solution and I think it's been our task and everyone in this room and at this meeting to really broaden the scope of osteotomy and make it also a very powerful American solution. We talk a lot about knee joint preservation. We talk about the joint as an organ system. Clearly there's many different parts of that organ system and I would argue that the main pillar that we all need to conquer before we think about biology, cartilage, meniscus, et cetera, will be and is the alignment. And I think we do have to, you know, look at our outcomes and challenge some maybe misconceptions or previous thought processes that we might have had about what we can achieve and what are the outcomes. And, you know, frankly I think even in very highly active populations when we're talking about returning to higher level duty, for example, in that military study, talking about work, talking about sport, osteotomy is as good or better than any of our other joint preservation techniques in the arsenal. And so you can kind of see here in this study return to work 80 percent, return to play 82 percent. You saw the military study was 72 percent success. So, you know, these are challenging situations and we can certainly get good outcomes. This is a database study that we looked at, greater than 1,000 patients, cartilage restoration plus minus osteotomy. And the bottom line is when you fix alignment along with joint preservation and cartilage, we actually reduce our risk of reoperation, similar rate of complications, and over the long term similar overall costs. And so I think, you know, that gives me some assurances that we're sticking to principles and getting this right. I looked at my own learning curve. Some of you may be starting practice or in your early practices but, you know, this wasn't something that I jumped into right out of fellowship. I did a couple and then I went to courses and then I went to the lab and then I, you know, kind of trickled. And you can see in my, you know, I think year three or so I started, you know, being comfortable with my bread and butter sports medicine practice enough to really start taking on and getting referrals and getting complex. Then like anything you probably do a little more and then it balances out over time. So, you know, I think just because you don't want to take on your craziest and hardest cases right at the beginning. You want to make sure you know how to do ACLs and rotator cuffs or whatever else you do first and you want to treat these people, you know, non-operatively and have them come back and fail. And you want to make sure that, you know, their percentage of normal is low, their pain levels are high, that you have those marginal gains before you kind of go forward. So just some things I think about. So, you know, malalignment selection, really malalignment in the physiologically young active patient. So this is one population for HTL, obviously, the symptomatic mild to moderate unicompartment arthritic that's either medial or lateral. Typically patel femoral would be asymptomatic in those cases. Usually the malalignment for these types of cases is greater than five degrees. I like this chart from our friend Bobby Doerr. Basically just looks at some of the variables that you might have to decide with your patients. When you're thinking about HTL versus uni, I do both in my practice just like I do PFJs and TTOs so that I can have this balanced conversation. I have tools in the toolbox and they're different based on patient age, a little younger maybe for the biomechanical solution, a little bit more arthritis maybe for the uni compartment. If you have more deformity, you'd probably lean toward deformity correction. If you're more active, likely leaning towards osteotomy. If your patient has a higher pain tolerance and wants to climb mountains and be rigorous, then you're probably going to lean again in the osteotomy direction versus uni. And like anything, there's a gray area. So I think this is just a good way to kind of help frame your thought processes going forward. And then the other group that we treat a lot are these patients with those symptomatic focal cartilage defects and or meniscus deficiency. The ones that might be or are candidates for cartilage restoration, meniscus transplantations. And in those patients, I'm accepting less malalignment. And so really anything greater than or equal to three degrees. The other subset that we see is these refractory, not sure why the timings are on, sorry guys, refractory or recurrent ligamentous instabilities. So varus with a chronic posterolateral and valgus chronic medial or posterior medial instabilities. And obviously, we can start thinking about slope for both ACLs and PCLs in the chronic or revision settings. And how we might play around with two-plane corrections to help with our ligamentous instabilities. Contraindications are pretty standard. Flexion contractures, I think one, I wouldn't call it necessarily at this point. Contraindication, but when you have extreme amounts of malalignment, particularly when the wapering line is not going through the bones, that's when you might start thinking about some of the more complex things that will be presented by, I think, Al and by Armando. Patients like this probably wouldn't be perfect candidates for the run-of-the-mill standard high tibial osteotomy. And then we could talk to the panelists about nicotine smoking, BMI as contraindications, and whether they offer to their patients or whether we're considering closing wedge type osteotomies over opening wedge for some of those more challenging type patients. We always have to think about what is normal anyways. There's obviously a bell curve to normal. And I think this leads into, of course, our workup. We're doing all of our standard weight-bearing, APPA flexion, lateral. I do some sort of axial patellofemoral shot. For most, if not all, patients in my clinics, it's kind of a tertiary referral, so I'm getting mechanical axis views. And then we might talk about, for sagittal plane, selective long-leg tibial X-rays as well. I want to look at symmetry versus asymmetry. In general, I'm more apt to act on something when it's asymmetric, when it's a changing dynamic process, versus physiologic. And I think looking and being aware that these deformities are not necessarily just in one place. They can be on the femur, tibia, combined, coronal plane, sagittal plane, rotational. And so it's an evolving and dynamic process. We do need to at least understand what the measurements are, what the threshold values are. And I think when we're all starting out in this, and some who don't have access to some of the newer technologies, you're basically drawing lines, either on paper, on computers, checking angles. And I think the ones that are obviously most important for our coronal decision-making are our Milkowitz line, our lateral distal femoral angles, our medial proximal tibial angles. But also looking at that overall mechanical axis deviation and looking at what's called that joint line convergence angle. Basically, you want that to be as close to zero or lined up perpendicular to the floor as possible. And then we can measure also in the sagittal plane. This is an interesting image from Aaron Critch, just making us aware that it's not just about the bones. The ligaments can also play a role in this and can lead you to template an over or under correct in certain scenarios. So just be aware of this, particularly in those complex chronic or multiligamentous knees where you're doing osteotomy. And maybe there'll be some of those examples from our panelists. Certainly we've learned also that more is not always better when it comes to corrections. As you see here, survivorship of osteochondral allograft in the patients who are put to neutral versus put into too much varus or too much valgus. And so the amount of correction is really patient specific. You can see for cartilage restoration or meniscus transplants, typically going down the middle between the spines. Whereas when we're talking about osteoarthritis, if it's a varus knee, we'll probably correct them over to that 62%. Whereas in a valgus knee, typically I'm still putting them closer to neutral. I'm not tipping them more to the medial spine into varus. And we can see if anyone disagrees about that in discussion. Again, the exercise of learning how to create and template your osteotomy is a useful one. But at this point, there are many different proprietary ways that you can play around with this in different softwares. And so I don't think we're etching this out on paper anymore. But you do need to be aware of what the derivation of our current automated templating comes from so you can stay out of trouble. And I think a good place to learn that, for example, we'll probably be going through that in that AOSSM Issacas Osteotomy course coming up and other forums like that. I think when you're starting, you want to be honest about your surgical times. If you're doing multiple stack procedures, obviously think about foleys, think about padding the opposite limb, think about padding the arms. These can be longer cases, especially when you have to do multiple things. I've gone back and forth with tourniquet. It'll be interesting to hear from the group their thoughts and preferences. On the positive side, using a tourniquet makes me more efficient. So I can do big and multiple cases faster. But then you think about the bone and you think about, you know, you really don't want to heat up the bone when we're going for bony healing in the longer term. And so that would go against using tourniquet for the osteotomy. I think many of us have been using TXA, similar to the joint replacement doctors. And then I think you want to have a plan for worst case scenario. At least know where vascular is, know where the blood bank is. Just plan for the worst and then try really hard to avoid it. Drains, I typically keep a lot of these patients 23 hours. I have a low threshold just to put a drain in and take it out in the morning, regardless of what it puts out. Most of these patients will be getting just some form of femoral or adductor block, either a catheter or single shot, typically not doing IPAC or any kind of posterior chain blocks. And as I said, they stay overnight. We'll just go through briefly kind of the principles of the different options for the tibia. So we'll start just with concepts about a lateral tibia closing wedge osteotomy. Anytime we do these closing wedges, it's good healing. You can weight bear it on it essentially right away. However, it's less familiar. It's a bit harder. There needs extensive surgical dissection. We need to think about the tib-fib joint. There's the peroneal nerve on that side. You can shorten the limb. And so, you know, I think these types of issues, especially before we had some of the patient-specific instrumentations, you know, really led us away from a closing wedge, both on the femur and tibia, at least from my early experiences in fellowship and in early practice. But nonetheless, you can see where there might be advantages for patients with larger BMIs. Smokers, I don't typically take care of, but if I had to, I'd want to do a closing wedge. And then you can get a lot of bone graft if you need it for something else. So those are all kind of considerations for lateral tibia. But the bottom line, I think that the workhorse is the medial opening wedge for the vast majority of these patients with these uniplanar coronal deformities. And it's a familiar approach. There's less surgical dissection. We don't have to go around the tib-fib joint. We can titrate that correction after the osteotomy, which I think is a huge benefit of opening wedge, where it's harder to dial in with closing wedge. The medial side is a bit prominent, so hardware removal can be an issue. And it does have to heal, so with larger corrections, delayed weight-bearing status, thinking of bone grafting. Probably in America, we bone graft more than we should, but greater than 10 degrees, I think, if you're going by the evidence, you should bone graft. And we have to think about fractures and non-unions. One thing that does come up is there's peak implants out there. And when you look at the limited amount of data, peak versus plate, the corrections were similar. The removal of hardware rates with the peak were less. I'll tell you that of those of us, I think, who did these are no longer doing many or any. I had a few that were infected. I should have put them in my talk, Neil, next year. Sorry, buddy. But... But... It's actually a complication. But infection, obviously, of a peak implant can be a disaster, and loss of correction can also be a challenge. And so, I don't use that anymore, but it's certainly out there in the literature. Avoiding complications, really, we're talking about dreaded ones like this, hinge fractures, and there is a large risk to that. And we see here, Al and I wrote this paper with one of my fellows, just looking at the safe zone for osteotomy, so that we can protect that hinge at all costs. There are different proprietary ways to protect the hinge. There's these golden pins, golden screws. There's other mechanisms or techniques that you can see to protect that hinge. I think one of the key points is just to know that it can be an issue, particularly with larger corrections. Look for it intraoperatively, and have a plan beforehand so that you don't get worried about it if and when it does happen. And so, the good news is that with the types of fixation that we have these days, I think the majority can be treated with just the standard plate technologies. If it's a relatively stable fracture, obviously you can put a staple, or you can put a screw in on the lateral side as well. If you have a fracture that extends up to the joint, again, I think you can definitely bridge that fracture and fix it with good compression. And so, you need all these tools available so that it's just an easy pivot if and when that does happen to you, and it likely can and will happen to you over time. You want to protect the soft tissues, patella tendon. Management of the medial soft tissue sleeve is also very important. We can talk about how we might do that. I think we're getting to some concordance on how we manage the medial sleeve, particularly those of us who are using patient-specific instrumentation. Neurovascular issues are rare but catastrophic. It's probably what keeps most people out of this room because they don't want to think about sawing in and around and near an artery. Luckily, it's only a very, very low percentage in high tibial osteotomy. One thing that you should think about and look for every time is the aparent anterior tibial artery. It's likely seen you, and have you seen it? The issue is that it can live close to the bone. It can live deep to the popliteus, and it can be at very much risk with your high tibial osteotomy. You can look and should look, and I do look with my fellows every time we're doing our plannings. That's part of my preoperative plan. Changing slope, don't change it unless you want to. You should have that two-to-one relationship from back to front, but you can manipulate the slope for ACL or PCL and use that to your advantage. I think the biggest issue with HTOs previously has been increasing that tibial slope, which can be a real problem, particularly if you're combining that with an ACL kind of reconstruction. Patellofemoral complications, particularly patella baja, can be an issue with medial opening much more than lateral closing, and degenerative changes of the patellofemoral joint over time. Again, bigger concerns for this will be with large corrections, particularly if you're starting in some baja, you might make more baja, and then also, as they may talk about, with slope corrections, particularly large slope corrections, you can create some patella alta, and so just things to think about. There are ways to get around this, either adding TTOs, which obviously stack some morbidity and risk and technical considerations, or keeping the tibial tubercle pedicle with your proximal fragment, and then your patella height does not change. The rates of other common things that we think about, infections, DVTs, PEs, delayed unions, non-unions, are listed here, and the typical and classic risk factors, diabetics, smokers, et cetera, increase those types of risks. Converting to totals, it's technically demanding. Our joint colleagues don't love this, but when we look at outcomes, at least it depends on who you ask. From us, there's similar 10-year survivals, radiographic results, but it is longer OR time, higher infection risks, and there is concerns with stiffness for those patients, and so just to go through very briefly, other considerations, lateral opening wedge, HTO, these can be used for minimal amounts of valgus, five degrees or less. These do affect change. Whenever you do something on the tibia, you affect change in extension and flexion, so if you have young, active patients with posterior lateral compartment wear who are loading this inflection, this might be a good option for you, and there is evidence to support it. Similarly, medial closing wedge HTO, something I've been using and dabbling with for some of these small corrections because it's a more familiar approach. Obviously, we do medial opening wedge HTOs a lot, but there are concerns about joint line obliquities, but this series with almost 10-year follow-up, patients were doing quite well, and then I think in the interest of time, I'll have these guys talk more detail about PSI. I'll just say that I am using actively my practice, and it has allowed me to get much more thoughtful, creative, innovative, combine osteotomy with ligament, combine it with root, do biplane cuts, do multi-level surgery, so I really didn't have this in my toolbox even as much as two to five years ago, and I think I'm still in a steep part of my learning curve with that. So hopefully, this kind of set the stage for the others. Alignment's obviously critical. Osteotomy is a powerful tool. The techniques vary based on patient factors, concomitant issues, the amounts and location of the deformity. We obviously are all here to strive to avoid complications. We can at least mitigate them with thoughtful pre-op planning, meticulous technique. This is from Bernie Bach, who, one of my mentors, really reminding us to like our patients, but love your complications, and if you're gonna do this work and do it often, you're not gonna be perfect, and so you really need to give those patients the most access, care, love, attention, cell phones, whatever it takes. Just be there for those patients. Don't run away, and then obviously keep pulse on the field. Keep learning from the innovators, and I think we're in a very exciting time for osteotomy in America, and I'm excited for the next decade and beyond. So thanks, guys. Great. So thanks, Seth. That was great. Any questions from the audience while we just get the slides up? I do have one question. Yeah, go for it. With the biplanar HTO, I've seen it like going north, proximal to the joint, and then you have the one slide that was showing cutting it south, like distally, so that's so you don't change the patella height. Yeah. I think, you know, so terminology-wise, and these guys might get into it, there's biplane corrections and biplane cuts, so I think you're talking about a biplane cut behind the tibial tubercle. The most standard and typical cut is when you have that cut attached to the distal fragment, which is different than what I showed there, right? So that's if you want your osteotomy to be lower, if you need more real estate for, let's say, ACL or otherwise. Al, are you doing biplane cuts routinely for your standard HTO, for stability? Is that your name? For stability, increased surface area, load of benefits. Yep, so I think- And your cut's lower. Yeah, so when we learned, we never did that. We just did the one biplane cut, usually at the level of the tubercle or above, but now that I've been using PSI in my model and it gives me the angles that Al learned in his sleep as a young kid doing osteotomies. But certainly on the femoral side too, it's not a femoral cut, but that biplane cut that is similar for you, it prevents some of that sagittal plane deformity, it gives you broader surface area and more stability. So I'm using that routinely on the femoral side, and then I'll play around with whether, for me, I'm much more apt to add if I have cases of extreme patella height issues, I'm gonna take the tubercle off and just do something to the tubercle instead of do that cut where I leave the tubercle pedicle on the proximal fragment. But you certainly can do either way. Cool, thank you. Yeah, I mean, I think the biggest point is that the word biplane is commonly confused in the literature and in conferences. Are you talking as an osteotomy or are you talking about correction? Because when we say biplane, is that a coronal correction and a slope correction? It's kind of a confusing term. But the traditional AO technique is to cut the tubercle and then you have the distal cut, which you showed, which is to not create Baja, which is a more unstable osteotomy, and then you need A to P fixation that you showed. And Bob actually has a paper recently. And so there are a lot of papers about that. I don't know, I mean, Al, do you think it matters if you go distal when you preserve patella height? Do you think outcomes change or, because there's been, it makes the x-ray look prettier. It's a harder osteotomy. Do you think it matters? Yeah, so Paul Giffen did a study with Dave Long and others, and they showed the corrections over 12 millimeters if you did the distal biplane, then it had less issues with patella height. Terms of actually long-term when it comes, that's just not really there in terms of actually reducing the pain or whatever. I think it makes sense. Yeah, I mean, it definitely makes the x-ray look better. There's another paper out of Careers saying they had no difference in outcomes, but it goes back to the fact if you're doing bigger than 10, 11, 12 degree corrections, you probably have to think about double level. You probably have to start thinking about going in for below the, otherwise you're gonna go back to Seth's point of the hinge fracture kind of stuff. So thanks, Seth. That was awesome.

high tibial osteotomy

complications

alignment

joint preservation

reoperation risk

patient-specific instrumentation