And I guess my main disclosure is that I love doing TTOs, but I reread our paper, and I just am not sure when we should be doing them. So we'll dive into that a bit deeper. Here's the spoiler alert, the take-home points, my current indications. So by far and away, this is the main one. Antermedialization to unload cartilage. So that's at the top of the list for me. Distillization for severe patella alta, and we'll talk about that. And then medialization without cartilage for instability is becoming extremely rare in my practice, and I think in others' practices as well. And so it must not be a knee jerk. You like that? TTTG greater than 20 is not equal to TTO, and hopefully you'll see why in a couple of minutes. Of course, we all need to accurately measure, and we know how to measure coronal and axial and sagittal, and we wanna put it all together, but we need to take any threshold values that we have and that we communicate with each other with a grain of salt. How accurate are our measurements? If you go through our recent literature, TTTG clearly varies by age, by gender and size. It varies by the imaging modality we use. It varies in the presence of trochlear dysplasia, where is the actual TG. It varies by flexion angle. And so what does it actually measure? Is it measuring femorotibial rotation, is it measuring some version and torsion, is it measuring that lateralized force vector, is it measuring sometimes a medialized groove, or more realistically, some combination of all the above risk factors. And so if TTOs are hammers, everything a nail, I don't think we should be treating all those different pathologies with just one tool. So we need a lot in our arsenal. We clearly are learning different measurements, such as TT-PCL, which can help us. I think other measurements on our standard imaging, but also 3D CTs and MRs and collaboration will get us these answers. It's really important for us to remember that isolated MPFC reconstruction, whichever you choose, is a workhorse. It gets great outcomes, even in the setting of trochlear dysplasia. And so I think my task here is to identify when we really need to do more, and hopefully to bring it back to the clinics for all of us as we go home. So I asked the question, when does isolated MPFL fail? And I think it's pretty clear that it fails when you have these very large J signs, not the ones we argue about the subtleties, but the ones the med student can see as well, when you have seated examinations from flexion to extension. And that's a summation of typically ALTA dysplasia or other combinations as well. And so ALTA falls into there as well. I think a useful tool is apprehension in deep reflection, not just typical zero to 30. When you have apprehension and or laxity that's asymmetric at 60 and even deeper, you should get your red flags up and you should be thinking about these other abnormalities, typically ALTA dysplasia or other combined rotational or other abnormalities as well. I also think about when a well-done soft tissue stabilization has failed. So not just a patient who had a lateral release or an imbrication with underlying risk factors, but a well-done MPFL reconstruction or MPFC reconstruction. That's when I start thinking about obviously adding a bone procedure to my revision. Younger patients, bilateral lower energy dislocations, and those syndromic patients also, I think are more reasonable to consider bony and soft tissue stabilization. Coming back to my main indication, this is an infographic that Jack Farr and I did to try to simplify a complex topic. But I think the biggest point, if you have cartilage defects and you think they need to be unloaded, you can do an intermedialization, a classic Fulkerson, and then add soft tissue stabilization if needed for instability. If you have panpatella, medial, bipolar disease, you can do the same type of AMZ, but you can also add cartilage restoration to the mix and soft tissue balancing, and I think you can get the result that you want. We just published in Cartilage, looking at a database study, and adding osteotomy to cartilage repair reduces the reoperation rates with similar complications and similar overall costs. So very low threshold to add osteotomy to cartilage repair, very low threshold to unload cartilage defects and isolation in the setting of instability, particularly if you have painful episodes between biologic effusions, mechanical symptoms, et cetera. When to add distalization in patella instability? I think this is still a moving target, it's controversial. Biomechanical studies, if you're looking purely at favorable anisometry or isometry, may suggest a Catan-DeChamp as low as 1.2. However, if you look at clinical practice and some of my colleagues are even taking this further in prospective cohorts, really just doing isolated MPFLs for Catan-DeChamps that are way higher, this threshold may be upwards of, excuse me, upwards of 1.4. I would submit, this is a patient of mine, bilateral patellofemoral instability, severe ALTA and dysplasia. I don't think there's any way I can solve this problem without adding a tibial tubercle osteotomy, and here you can see staged bilateral osteotomy, soft tissue stabilizations, getting that Catan-DeChamp down to 1.1. And I think our literature, while somewhat sparse, does support distalization for these types of extremes of ALTA. There's also growing cohorts supporting combinations of tibial tubercle osteotomy and MPFL for these other combined risk factors. So I think if you identify the red flags and you have to do more and you're doing a tubercle osteotomy, then we do have some backing to support that this works. And my cohort that I presented last year at this meeting, similar, no differences in their baseline scores between the groups, MPFL versus MPFL and TTO, and then significant improvements in their COOS domains and their PROMIS and IKDC, really no differences across the board. So with strict indications when to add TTOs, I think you can get the same outcomes that you might get with isolated MPFLs. In this group, which was a short ERR term follow-up, it took longer, obviously, to get their Tegner scores, their activity scores up to snuff. So it's a bigger operation that has more morbidity and it takes longer to recover from. A couple of other points, don't ignore extremes of femoral antiversion. So if you have outliers, I think you have to respect that and potentially treat it. Here was a major outlier for me. I've asked some in this room about this case, but this one had multiple failures of patella instability surgery, had a antiversion of 50, had severe dome dysplasia, obvious patella tilt, patchless medial soft tissue structures. And I feel like you obviously have to do more in this kind of repeat revision scenario. And so luckily I went to literature. I asked my friend, Lori Hiemstra up in Canada. She sent me a paper and I mustered up the courage to get some other tools. And I did a distal femoral derotation osteotomy. And I also, in this one, corrected that trochlea and deepened the trochlea and then did soft tissue balancing. And he's doing quite well at, right now he's about six months, but he healed everything and he didn't get stiff or have any other catastrophic early complications. You can see the stability intraoperative. As I'll talk about in a minute, Liza's taught me to look at that tibial tubercle sulcus angle, you really want that zero. So you want it right dead down the middle at 90 degrees. That can help you so you don't overcorrect. Just to show you when I may not do a TTO also. So here's a kid, he had recurrent patella dislocations. He had asymmetric valgus, dysplasia, multifocal lesions. So patella and lateral femoral condyle, weight bearing lesions, young kid. And so putting it all together for me, for this one, I corrected his valgus to neutral, soft tissue balance and did my cartilage repair of choice. Where in this one, it was a multifocal Macy. And he's way out now from my time at Mizzou. He was doing quite well at a year and better at two years. But I think hopefully a comprehensive joint preservation approach in this case got the job done. And I'm not sure that the TTO would have been the answer there. And I'm really not sure in the case before if the TTO would have been the answer for the bony procedure. In the last couple of minutes, complications are real, especially when you unhinge the osteotomy, distalization. These are some of my complications. Early and late. And it's obviously humbling. This is some work I presented, just looking at when you did an AMZ versus a osteotomy that included distalization. I think I've learned a lot from that time as far as soft tissue periosteal preservation distally, maybe different ways that we cut distally that I'll show you in a moment. Adding a proximal buttress, going a little slower with the rehab, and a host of other things that I think are important. We obviously don't want to over-distalize and create Baja, so you have to do some simple orthopedic math. And I like to go to 1.1. I think Liza wrote a very nice editorial commentary recently really highlighting the use of the tibial-tubercle sulcus angle intra-op, so you don't want to over-medialize either. And then lastly, I'll just turn your attention to a technique that I've been using for the last three years, and I've had the fortune of working closely with a mentor and friend, Al Merchant, who's as passionate as I think ever. And this is his brainchild that he developed over several years in his career. And you guys can stop me if the video goes too long, but the idea here is basically that you're making cuts within the cortices, so you're really not cutting the classic way where you would come out laterally. You really need minimal lateral soft tissue dissection. And so here you see the completion of what we call the primary wedge. Then we can measure precisely and cut out if you're medializing a secondary wedge, so that's medial to the left. And then as we move along with the osteotomy here, you can see unhinging at the top. That's the standard way we would unhinge in any case. And then we'll see here in a moment that we are unroofing the primary wedge and that secondary wedge from the bed. So you see how it's all within the cortices and really minimal soft tissue dissection. In this case, I'm doing a distalization. I really only have to take off a few millimeters. I preserve the periosteum, I widen the kerf, which means just taking the saw and widening distally. And I can get the eight to 10 millimeters that I need, and I can measure precisely distalization, anterization, medialization, or combinations with this technique. And so I really like it for two to three planes. You do need to bone graft. I've used a headless screw fixation because my reoperation rate for screws was way too high. And you can see that proximal buttress, and then you see the centralized tracking. So hopefully in this brief amount of time, I've shown that TTO can be a powerful tool to correct patellofemoral malalignment in the setting of instability and or chondrosis. Think the indications and techniques are evolving. You notice that I didn't just throw numbers at you. We'll have to be more thoughtful in our analysis of when to include this. But I think that we can work together on patient selection, meticulous technique, appropriate rehab, and we can get excellent outcomes. And I thank you very much for your attention. Thank you. Perfect. Thanks very much, Seth. And don't forget, you can use the app for throwing any questions our direction, but also if you just want to put up your hand and shout out a question, please do. I'll just start by asking, what's your post-operative rehab for a standard distillization, say? Yeah, I think with this system that I'm using now, it's become much more in line with any tibial tubercle osteotomy. So I'm really not differentiating much between medialization, intermedialization, distillization at this point. However, I still go pretty slow with them. I use a hinge brace. I use it locked. I like foot flat, 0% weight bearing. And typically for up to six weeks, although Al Merchant's pushing me to go faster, I take them out of the brace for gravity-assisted range of motion and or CPM immediately. So I have really no significant restrictions on range of motion, but I do restrict weight bearing. I get x-rays at zero and then at six weeks and then transition to unlocked brace and then out of the brace for sure by eight weeks and walking normally, rid of all the stuff by three months, I kind of tell them. Perfect. Any questions from the floor? Nope. Just one quick one. And the distillization, do you wait till the entire anterior cortex is healed distally before you allow them to run radiographically? Yeah, so I think the catastrophes that I showed and were kind of step cuts and I think that the osteotomy was a little distal into the diaphysis, there were healing issues and dreaded black line. With the osteotomy I'm doing now, that's tapered. I mean, I really don't even see any distal line at all at time zero. So I couldn't even tell that. I'd have to look at advanced imaging to do it. That's the best part of that technique is that you can't actually see the radiographic healing. Yeah, I mean, I've had. So you just treat them symptomatically. It's great. But you would know. Perfect. Thanks very much, Seth.

tibial tubercle osteotomies

patellofemoral malalignment

instability

cartilage defects

patella alta