So I'd like to introduce Dr. Seth Sherman from Stanford. He'll be talking about coronal and rotational malalignment. Good morning, everybody. Miho, thanks for the invite. The four of us are very passionate about patel femoral. And judging from you guys being here bright and early, it seems like you are as well. So hopefully, this will be an engaging session. My task is to talk about coronal rotational malalignment and to figure out how and when to incorporate medialization or intermedialization type tubercle osteotomy into our thoughts and algorithms. My disclosures are online. My personal disclosure here is that this was a challenging talk to make, Miho. It's led to some great confusion and challenged some of my dogma. And I'm hopeful for all of us that I can share that journey with you and that it might lead on the precipice of some clarity. So that's kind of my hope here. The deal is that these patients are seeing us. And we're going to talk about red flags like apprehension, inflection. We're going to talk about J signs. But a subset of them also have these other things like coronal malalignment and valgus. And if you turn them prone, you can see they might have increased internal rotation or thigh foot progression angles. So are we really catching these patients? And are we treating them appropriately? We know we can't use the NPFL to pull the patella anywhere. We must understand and correct bony malalignments and then add soft tissue stabilization as a check brain. So that point's clear. And we know that isolated treatment of the NPFC, the complex, is our workhorse, even in the setting of some of these isolated pathologies, such as trochlear dysplasia. So then it comes down to when to do more. And that's the theme today. And so when do isolated NPFLs fail? Again, jumping J signs. We'll talk about what that means. Apprehension, not just at 0 and 30, but at 45, 60, and beyond. And we have to also recognize and think about the effects of femoral rotation inversion with these high J signs and the risk of soft tissue failure. But what does do more mean? You can see here there's a lot of targets. We can rotate, derotate. We can reshape. But which one do we choose, and in what combination, and when? And there are many anatomic considerations. And when you look at this list, we look at version. We look at torsion. We look at ALTA. We look at dysplasia. We look at things that influence the lateralizing force vector of the patella. But notably, on this particular schematic, where is lateralization of the tubercle? I mean, it's not in the algorithm, per se, here. And why is that? So we obviously have to ask some of the greats. This is Bob Taichi's thoughts and work. And so when you think about this, we have the restraints. We have the NPFL, the lateral side, and the trochlea, and then things that influence our lateral force vector of the quad. And so for him, that's valgus, torsion of the femur, and rotation of the tibia. And so that's the way that his mind's really geared to think about this, not necessarily that the tibial tubercle is lateral in the majority of cases. And so our good friend and colleague, Vicente Sanchez Alfonso, similarly thinks about the clinical red flag. So you can see them on the top, the apprehension, the J sign. And then goes to the trochlea and rotation. Clearly have to treat the soft tissue. But when to do more for him is really, again, not just about the tubercle. And so I think this is just eye-opening as I move through my journey. Here you can see what happens when you move the tubercle. Lateral, yes, the force vector does increase. But it increases much more with valgus. And it increases much more with version. And it increases way more with combined problems of those. And so they're really likely, behind the scenes, driving the bus, even in a subcritical way, in a majority of our patients. So I guess the key point, we think about limb alignment and not patella alignment. You can see the patellas are straight up and down in that view. And the femur and tibia can rotate around it. And I think that can lead to significant pathology and maltracking. So let's go back to AMZ and patella instability. You can see that little box all the way down on the bottom. And we have to remember that when John Fulkerson popularized and brought AMZ to the forefront in American culture, it was really a pain surgery. It's for painful malalignment and chondrosis. And so where along this American journey did this really come to become our knee jerk, TTTG20 equals TTO for instability. And so I think this paper and others will challenge that. So I was just with David de Jure. Fortunately, he got to spend time in his OR and at the ESCA meeting and went to the ESCA patella femoral consensus. And again, crickets about medialization and anteriorization. So we're talking about two different things on two different continents here. It's just fascinating. But I think we all can agree on this, that different from dysplasia and ALTA, TTTG is a risk factor, but it does not individually lead to patella dislocations. And then again, on his laundry list, and you can read it in the program, again, it's really not focusing on that lateralization of the tubercle. And why is that? I think we just can't trust TTTG in and of itself. It varies by age, by gender, by size, by measuring technique, CT, or MRI. It varies in the presence of trochlear dysplasia. It varies by knee flexion angle. What is it actually measuring? In this paper, it's really measuring femorotibial rotation in the majority of patients. So what about that lateralized tubercle? It could be a medialized groove. It's likely some combination of all the above. So I think we need to be thoughtful about why we're using measures and how. TT-PCL, a good thought or concept to try to tease out whether it's coming from the tubercle or not. There's other evolving measures that we should keep our pulse on and the eye on to try to really see where the deformity is and maybe correct there. This is a slide that Liza had given me previously, just basically taking patients with a TTTG above 20, and almost half of them did not have a lateralized tubercle. And so rotation clearly is there and driving the bus in a lot of deformity. So if TTOs are hammer, is everything a nail? I'm not sure. When to do a TTO? I reread my paper that we wrote years ago. We have to rewrite it, and it's just the bottom line. And we will, because it's complicated. But to cut to the chase here, I use TTO and instability for intermedialization to unload cartilage. So that's my main indication for instability. Andy's going to talk about distalization for ALTA, which is a workhorse. And I think he'll cover that outstanding in a moment. Isolated medialization, for me, is an almost never event. And I hate saying never on a podium, but it's true at this point. And we can talk about why. So here's our infographic for cartilage. Just very briefly, this is not a cartilage talk. But if you have distal lateral defects along with instability, you can do an intermedialization. You don't need to treat the cartilage. You align the bones. You can stabilize the soft tissues. And I think we can replicate John's good or excellent outcomes in upwards of 90% of patients, as you see from the cartilage mapping here. Similarly, if you have medial, central, or panpatella defects, that's where they did not do so well with isolated intermedializations and where you might want to add cartilage restoration to the mix. And obviously, if they're unstable, we want to stabilize the joint. And I think you can get 70% to 80% good results with a strategy like that. So that's really, for instability, where my TTOs lie. So where do we go from here? Hopefully, moving towards that clarity, mentor from HSS, Chit Ranawat, says that the eyes see what the mind knows. And I think it's a very true statement. If we start looking for internal rotation, flipping patients prone, looking at these other angles for tibial torsion, we'll start seeing them and understanding them better. We can scrutinize these strange-looking X-rays for rotation and just think that there's more going on here and that we should dive deeper, perhaps get axial imaging CTs under MRIs. We obviously need to accurately measure in all planes. But I'd implore us all to take these threshold values with a grain of salt. This is a paper that recently came out just looking at normal for rotation. So you can see the numbers here for version and torsion. Female hips were more verted than males. Caucasians, less verted than Asians. More externally rotated tibias. And age and BMI really didn't correlate. So at least this gets us in the ballpark for what normal might be. Thoughtful pre-surgical planning. So I work a lot with our radiology team and any interested students to develop protocols. They include rotational profile spot imaging of the femur and the tibia for the MRIs. And they do 3D reconstructions when they get CTs in those challenging and rare cases. So these are tough, and more information is better. The question's always, do I need to do more than the MPFL? So Miho really hit it on the head. And then what does more mean? And so these are the measurements that I get from those imaging. And then I go through the mental exercise. Whether the TTTG is elevated, is it coming from the femur? Is it coming from the tibia? Is it coming from the tubercle? Is it a combination? And what's the valgus angles? And then putting it all together to try to do the least amount for the maximum gain for that patient. And I think that's the challenge. There's so many other factors, obviously. So I think machine learning is ripe for this. We've luckily been partnering with the Jupiter group to get data, to get imaging, and to start crunching these numbers. So that's a fun and important future direction. Just a few case examples to close here. I don't, at this point, ignore extreme version. So this is a patient of mine who had version numbers well above 40, lateralization of the tubercle, severe trochlear dysplasia with a large supertrochlear spur. And for me, this was a rare case where I asked colleagues and friends. They sent me a paper that was describing my patient. And then I went and I executed. And so here, you can see the derotational osteotomy that I did at the distal femur. And then that actually gave me great exposure for managing the trochlea. I do trochleoplasty rarely. And in this case, I did, deepening trochleoplasty, as you can see here. And I can get that entrance flush to the anterior cortex. And you can see I have two quadrant translation, medial, two quadrant lateral. When we get to 30 and we get to 60, it's nice and stable in the groove. And when you go to 90, you can see that the tubercle's right down the middle. Eliza likes to look at the tibial tubercle sulcus angle. So I think that's a really helpful tool, whether you're doing TTOs or other rotational osteotomies, that you've lined up the putt. And here's the kid. I think he's six months or more now, but he had a jumping J sign. He has no J sign. He's quite happy with his relatively early result with a stable knee. So that's kind of a case that might become more part of my regimen over time. Here's one, don't ignore, asymmetric valgus, an 18-year-old, multiple patella dislocations. You can see the asymmetry of valgus. He had dysplasia as a risk factor I didn't treat. He has multifocal defects, patella and lateral femoral condyle. Another reason to offload the lateral compartment as my choice. So I did an unloading osteotomy on the distal femur, soft tissue stabilization and cartilage restoration. You can see the radiographic imaging here and his followup. I think if we're doing challenging cases, we should at least get VAS and SANE scores. Put them in your notes. If not, collect PROs so we can compare apples to apples over time. And so he's probably about four or five years out now. These are some other things in the literature. So biplane osteotomies to correct valgus and torsion. Sounds intriguing, sounds challenging, but there's good outcomes in a small series. Supratuberosity torsional osteotomy. Sounds intriguing, can correct multiple problems. Sounds very challenging. And so for me, if I'm going to dive in those, I'm going to look at patient-specific instrumentation in osteotomies. I think we can make precise cutting guides and help us kind of do the baby steps to get there. I've started dabbling in single and biplane corrections for ACL revisions, for example. Here's a biplane I modeled for valgus for a young patient that was able to execute. I had not really used an anterior flange in my practice before, and I think it gives better stability. And so I don't know if you guys will like this analogy, but I think it makes sense. TTO for PF instability is like a toilet plunger. It's a familiar tool, and it solves the problem immediately, but it may not be getting to the exact root cause when we really think about it. Here's one that I did maybe five years ago that I might treat differently now or I might not. 15-year-old non-contact recurrent dislocation starting at a very young age, prior failed soft tissue, surgery at age 13, apprehension to 45, some lateral tilt, elevated TTTG, borderline TTPCL, normal patella height, low-grade dysplasia, subcritical values when you do a rotational profile. So a little bit of this, a little bit of that. And I needed to do more than a MPFL. And so for that one, I did a medialization or an intermedialization, even though they didn't have cartilage loss. And frankly, I got soft tissue balanced and it looks great on the right, and she did well. And the other side, she came back for. So I think that's just something to consider. And this is in our literature in America, right? Combined risk factors, TTL plus MPFL is a great operation. So we shouldn't throw it out. And then this case is crazy, just to get criticized. This is a total joint patient sent by my chairman who did not, and the patient did not want a revision. So he's loving his right side as a bilateral, hates his left side from the start, jumping J sign, as you can see there, and significant instability. We did all the studies. The tibial tray was a little bit internally rotated. And so the options were to revise the whole thing at a pretty young age, I think he's 55 or 60, or to try to kind of do some sort of stabilization realignment. And frankly, that's what he opted for. And that's what I did. And you can see his outstanding stability and central tracking, and we'll see. And so I can solve problems and instability in strange cases as well. So that's my journey. I'm still confused, but I'm getting towards clarity. Thank God for these guys for lifelong learning. And I encourage you to look at our Patel-Farmer Foundation online course that just launched, get involved with us, and look forward to some discussion. Thank you.

coronal and rotational malalignment

patellofemoral instability

tubercle osteotomy

bony malalignments

femoral rotation