We're going to go over this, this is sort of didactic, and I'm just going to show different techniques to what to do the tuberosity. But I'd like to be a little philosophical here. When we started teaching these courses about 20 years ago, I'd ask everybody, how many know what the TTTG is? And I would have no hands, they were just blank stares. And then about 10 years ago, these are fellows at our fellows course, and I would say, how many know TTTG? Everybody. How many knows TTPCL? Almost everybody. And then we'd be getting into a discussion. So when do you move the tuberosity? Now we're talking about when do you move it medially? And it would be a shout out, 20 millimeters. And so now we've gone full circle. So we didn't have any data, and then we had data, and then we were making all of our decisions off this data. Now we're back to, okay, we're going to look at the data. We're going to look at where it is. We're going to look at the whole limb. We're going to try to put it together. So the PCL references the tuberosity just to the PCL. So it's not seeing tibial femoral rotation. It's not seeing the influence of where the trochlea is. So if I get agreement between TTTG and TTPCL, boy, I think I probably should move it if it's elevated. If they disagree, then I have to look proximally. Is it rotation? Is it where the trochlear groove is? Why is there discrepancy? And that may influence my decision on whether to move the tuberosity or not. So I think the whole evolution of how we're approaching this is changing for the better because now we have some numbers that we can all talk about, but then we can go back and try to use some logic, common sense. So we're going to talk about rotational alignment. Well, Miho, this is, I've tried entering, no, okay, we'll do that. So I have disclosures. They're on the Academy website and they're up to date. So this is out of a book that Seth Sherman and I did several years ago and we're just looking at concomitant procedures and I'm just going to focus on the one, obviously the tuberosity surgeries. But I just want to make sure that you understand that when we're talking about all of these, some of these patients are going to have excessive femoral hip rotation. So I put everybody in the prone position and I assess their internal and external rotation. If they're past 45 degrees, I start thinking, well, maybe this is contributing. Some people go down to 60 or 70 degrees. They're going to get a rotational study so I can actually see what's going on. And so I have a fairly patellofemoral focused practice and I don't do the deep rotational osteotomy myself, but I send about four a year. So not very many, but when you do it, it's certainly powerful. So this is an example. This patient is certainly, we've seen a lot of these merchant views. The feet are straightforward. The lateral facet of the trochlea is markedly higher than the medial. This one really doesn't give you that flavor, but when we were measuring it, they actually did have excessive femoral anaversion. And so this patient was treated with a deep rotational osteotomy. And I just want to show you how powerful that is. This had no soft, there was nothing done at the knee itself. So it was all rotation. So on this patient, if that had been treated with a tuberosity medialization, I think it would have been a disservice to the patient. So we tried to identify the site of pathology and then treat that site. So valgus, when do I start thinking about it? I mean, a lot of these patients are in two or three degrees of mechanical axis, and I would encourage you to look at the mechanical axis, the short films, or even the longer knee films are inadequate. You really need to see the hip and the ankle. So when they start getting up above five degrees is when I'm starting to think that's probably contributing to their lateral force vectors. And so I'm going to do a standard distal femoral varus osteotomy, and you can see that doesn't exclude, because I went on to do a tuberosity surgery as well, but we want to treat all the different aspects of their instability. And we all like to make kind of a laundry list, and there's usually four or five or even six different factors that are contributing to their instability. So the way I try to approach it is, what's the fewest that I can treat and still get a good result? Because I don't want to just treat them all, oh, well, I've got eight surgeries here I'm doing to this patient. The knees don't like to be operated on, as we know. So trying to do the very least is best. So Adam's going to go through soft tissues, but I just want to show many of these. When you're doing it, you're trying to balance the whole patellofemoral articulation. And so even I'm talking about tuberosity surgery, I still need to do a lateral lengthening, so that when I'm moving the tuberosity, I'm not increasing the lateral forces. So this is the standard exposure. This is much larger than it needs to be. This goes back to tuberosity surgery, greater than 20. Don't stop there. It's just a number. It's not infallible. So don't hang your hat on that. When you see that excessive, go back, look at rotation. Bob Taiji's been harping about rotation for 30 years. Frank Noyes came out with a protocol on MRI, so you can actually do a rotational study with an MRI, which I think is great if you have an 11-year-old. I really don't want to put them in a CT and expose them to that radiation. So this is what I was referring to, comparing the TTTG to PCL. And if we look at them, you can see, if they're both normal, great, I know what to do. If one is high and one is low, then I really have to put my thinking cap on and go back and reassess the whole patient. So a lot of people don't like the TTPCL. I don't think I like or dislike any of these. These are just parts of how I'm trying to address the patient. So when to add the TTO to an NPFL. So it's when it makes the balancing impossible. And both Andrew Amos and Beth Schubenstein have shown, certainly with certain levels of lateralization, it's going to be almost impossible to balance. And Adam Yanke showed that with certain degrees of patellar alta, you can't get your NPFL to balance. It's just not going to be anatomometric. So you need to do the tuberosity surgery. So when you're talking about what's the order of doing these things. So I'm typically doing a lateral surgery to lengthen, but I'm not repairing it. That's just getting it open. I'm doing the tuberosity surgery. And then the last thing I'm doing, I'm repairing the lateral side, and then I'm going back to the NPFL. Because we want to have everything balanced before we go to that. So another one is, you'll see these, like that merchant view that I showed earlier, that was on the basis of femoral anaversion. Some of these are on the basis of where the tuberosity is. The patella is just lateral all the time. In the patellofemoral study group, there's sort of an argument. The South Africans, they really, they just want to fix the NPFL. They don't care where the patella is. Well, I do patellofemoral arthroplasty. So I see these people who I know when they were 18, their patella was lateral, and now I'm seeing them when they're 50 and their lateral side is worn out. So I would like to optimize the forces. So contact area, decreased force. So that's a role that I think with the subluxation, and we want to normalize it before we go on. So this is that example. So this is chronic patellar subluxation. They do have instability, but they're sitting out all the time laterally. Now, this can be on the basis of where the tuberosity is, it can be on the basis of patholaxity of the NPFL scar tissue, overtightness laterally, but I don't like this position for the rest of the patient's life. So we want to normalize that. So this is one of the guides that I helped design. I think most patellofemoral surgeons that have been out for a while, they just do this freehand. I think that's fine. If this is your first one, I think one of the two commercial jigs is going to help you come out where you want to posteriorly. You can see we have a retractor that protects the posterior neurovascular structures as the saw blade exits. And then we have our blyke, you're going, what's the angle? John Fulgerson's fellow several years ago on CT scans did just some measurements and thought that 60 degrees is about the maximum. So that's sort of the workhorse is 60 degrees. Because if you're enterizing 15 millimeters, then the medialization at 60 degrees is going to be about nine millimeters and nine millimeters is kind of going to normalize the vast majority of lateral positioning. So that's the workhorse. Beth Schubenstein more recently showed that we're probably overestimating it. Maybe we're more 50 degrees or 45 degrees. I just look at it afterwards. How much did I enterize? How much did I medialize? Did I set my goal? What's my goal? I don't want to put them back. So what is a normal TTGG? Well, it's between 10 and 13, somewhere in the literature. I don't want to get back to five. Ryosuke Kuroda showed if you do that, you're going to overload the medial side and also the medial tibial firmal compartment. So we don't want to do that. So I'm trying to take somebody who's a 24 and get them down below 15. So it's not an exact science, but we don't want to over medialize. So this is a nice flat cut that you have. So we have a good healing potential with that cancellous bed and most people are fixing these with two screws. Andy likes three fives because he has less screw pain. I typically like using four fives. I think in this case I was using the smaller ones, but you can see I'm measuring. So I got about six millimeters of medialization and about 15. So I was pretty steep on this particular one and you can see now I have normalized. I'd like to point out that you can see some of these merchant views postoperatively. You go, you didn't medialize it enough. Well, they've shown in the literature a couple of times that the contour of the articular cartilage, which is what's really important, does not match the bony contour. So MRI trumps plain radiographs on trying to decide the congruity of the joint. Patella alta, once again, this is a number to look out and then you say, well, what do I want to do? Everybody has a different little subset. Some patients have a very short trochlea. So it's not that the patella is too high, it's the trochlea is too short. Raleigh Biedert has talked about that. What I would like to do, I would like to have the patella begin to engage into the trochlea at around 10 degrees of flexion. So during these procedures, I use the numbers to say, okay, this is where I'm going to start, but then I will move it and I'll even palpate it as most of these are open procedures so I can actually physically see the patella. They're asleep, they're under a block, so I have somebody take a towel clip and I'm pulling the length out. You don't want to have it relax and make it a measurement on that. So we have a 1.4 and that's sort of the consensus that you don't want, just because 1.2 is the upper limit of the Gatton ratio, most of the time, because there's so many problems with the distalization, you just don't want to do it to everybody that has just a little bit of abnormal. So we got to have sort of markedly abnormal, 1.4, 1.5, 1.6, and so our goal is to get it back to normal. I don't want to over-medial it, over-distalize it. This is one of the ways, Filip Nere, this is his technique, basically making a trough so you have a lot of cancellous bone. The most distal aspect, now I'm actually taking the periosteum, before I make the cut, I'm taking a periosteum flap, I think Adam talked to me about this, taking a flap down and then distalizing it. I'm really trying to get this apposition perfect, and then I'm adding debia, and then at the end I'm putting the flap back over. Why? Because this is a killer right here, you get a delayed union, you know, six months later they're going out playing basketball and pop, they've got a tibial fracture, so that's not a very nice thing. So this is the amount, you can see now we've got 28, 28, so, and this is what I'm talking about, this is an older slide, I don't like that. That's kind of scary. Fortunately, most of these patients do go on to heal it robustly, but that one patient that doesn't really makes you feel edgy. Thank you very much.

tuberosity surgery

patellofemoral instability

rotational alignment

valgus

patellar positioning