Thanks everybody. So sorry about the delay. We can blame the elbow people, but I think we can get started. This is ICL 221, All Things Patel-Ephemeral. I'm pleased to introduce our faculty, our esteemed faculty, who are here with us. I'll be moderating. I'm Miho Tanaka. We have Bettina Hinkle from Beaumont Health, and we And so I think we're going to start with some talks and we'll have some great discussion at the end. Just as, you know, a little bit of a recap to get us started, as we know, patellar instability is pretty common, most common during adolescence. such as football, basketball, and soccer. And I think, you know, the stability is multifactorial, and this is what makes it a complex joint. There's the soft tissue restraints, the bony restraints, and the alignment, and all of these things can factor into stability and disruption of any combination. But for surgical treatments, the goal is to address the anatomic deficiency, so we have to identify and address the individualized pathoanatomy. We break this down into soft tissue deficiency, bony malalignment, which we typically think of as tuberosity, lateralization, and patellar height as the primary issues, trochlear dysplasia, and cartilage pathology. So I'm going to be talking about medial patella-formal complex reconstruction and how to avoid complications. I have no relevant financial disclosures. So a little bit about the anatomy. But it's all become a little bit of alphabet soup, so I'm going to talk a little bit first about what to reconstruct, how, and why. So the initial description. But over the past 15 years. This is a broad attachment. John Fulkerson has called these fibers the MQTFL. And he described this as a distinct ligament that's proximal to the MPFL. And of course, he described a reconstruction technique to avoid patella fixation. But other studies have shown that this is one ligament. So the MPFL and MQTFL are one ligament with a common origin on the femur, but that they're variable in terms of their attachment. And most patients and most knees have fibers that attach to both the patella and to the quadriceps tendon, divided almost half and half. Although some knees can have only patellar attachments, and other knees have been shown to have only quadriceps tendon attachments. So the question then becomes with this broad and variable attachment, if we're performing a single bundled graft reconstruction, where should we be placing the graft? And looking into this, almost more than half of these attached at this point, but all of them were proximal to this point. So this is a little bit more proximal in terms of fixation than we would normally think of with previous studies on the NPFL. But it's important to remember that this fixation is still distal to the superior pole of the patella. So if we're looking radiographically at what the correlating point, the radiographic point of this midpoint is, it's still distal to the superior pole of the patella. So it's not way up on the quad. And so I think that's important to remember. On the femoral side, this has been talked about a lot on the medial femur. We know that this is distal to the adductor tubercle, always posterior to the medial epicondyle, and generally sits in the saddle between the medial epicondyle and the adductor tubercle. It has an elongated footprint, so generally about 10 millimeters long and about two millimeters wide. So we think of this as a ribbon-shaped ligament. Now, the femoral tunnel position is important because we know that malpositioning of the femoral tunnel can lead to increased patella-femoral contact stresses. And we know that even six millimeters of malpositioning can lead to these types of problems. The most common errors that we see with this are that the tunnels are either too anterior or too proximal. Now, the anatomic point can be difficult to find. So a lot of these patients have dysplasia, their bony landmarks are not as easy to feel. And so oftentimes we rely on radiographs or fluoroscopy during the time of surgery to identify the appropriate femoral tunnel position. The most commonly cited one is Chateau's Point, which I think a lot of people have heard of, which uses the posterior cortical line as a guide. And so it's right along this line and a little bit distal to this. Now, if you are gonna use radiographs, you have to make sure that you have a perfect lateral. So Corey Edgar has shown that if you have some rotation or some abduction in the x-rays at that time, your marks are gonna be off. It's also important. And you have a short amount of the posterior cortex showing that can change the landmarks as well. And then lastly, we just presented yesterday that in So when performing MPFC reconstructions, there are multiple technique options. You can fix this on the femur. I'm sorry, you can fix this on the patella or on the quadriceps tendon. You can use autograft or allograft. You can do single versus double bundle. And really all of these have been shown to have good outcomes. For patellar fixation, if you're performing an MPFL reconstruction, you can use multiple fixation options, including anchors, docking, screws, buttons. Really, there hasn't been shown to be any difference between using a bone tunnel or using cortical fixation with anchors. I think the most important thing to avoid is the risk of patella fracture. So avoiding multiple holes or large holes in the patella. And Iman Dawan showed in his biomechanical study that if you penetrate the anterior cortex, because that's the tension side of the patella, this is what really increases your risk of patella fracture. So I think that's an important thing to avoid. There have also been some recent studies that have shown that distal fixation on the patella can tend to tighten inflection. So we wanna try to avoid that as well. For quadriceps fixation or for MQTFL reconstruction, this is on the quadriceps at the midpoint. So this is a suture fixation and avoids the risk of patella fracture because we're not drilling into the patella. I think the goal here is to avoid fixation that's too proximal. So to remember that this is still at the midpoint at the junction between the quadriceps tendon and the patella. For graft options, autograft and allograft have shown to have similar outcomes and the same redislocation rates. I think some studies have shown a slightly favor allograft, which is what I tend to use. Christian Fink has also described his technique of using the quadriceps tendon as an autograft and leaving it attached to the supramedial quarter of the patella and then swinging that over and attaching it to the femur, which is a really nice anatomic technique as well. And of course, this wouldn't be a sports medicine talk if we didn't talk about something double bundle or another. And so Min Koker's group has described their combined MPFL and MQTFL reconstruction with good outcomes and low redislocation rates with this as well. But I think when we start to think about the sort of double bundle or the different types of bundles in this complex, it's important to remember that, you know, the fibers along the top of this and along the distal portion are fairly different and that they have at least seven millimeters differences in length. So we can't really treat this as one specific ligament or with one femoral attachment. And so in this study, when we looked at the broad attachment on the extensor mechanism and on the femur, what we found was that if we're looking to have isometry, so we want to have graft lengths that don't change throughout range of motion, because if they change throughout motion, then the grafts can loosen over time. What we know is that if you're anatomic, so top to top, bottom to bottom, middle to middle, that these fibers tend to behave similarly and that they tend to be isometric. The ones that are attached to the patella tend to tighten inflection and tend to be influenced by TTTG distance. And then the ones that are proximally attached tend to be influenced by patella alta. For those of you who use the midpoint here, so this is kind of what we think of as Schottel's point or Fugino's point, which is one centimeter distal to the adductor tubercle, then the most favorable attachment point would be this midpoint, which is what we previously described as the junction of the medial border of the quadriceps tendon, where it meets the patella. So my current technique is a single bundle midpoint to midpoint reconstruction. I think with this, you can attach this to either the patella or to the quadriceps tendon. If I'm doing an MPFL reconstruction, I use a modified docking technique, but I've moved this a little bit more proximally in order to be a little bit more anatomic. And of course, if you're gonna move this proximally, you wanna direct your tunnel distally so that you have enough bone for this. This ends up being about a fifth of the way down from the superior pole of the patella. And then this is path, the sutures are passed and tied over a bony bridge laterally. In the same location, if you wanted to do an MQTFL reconstruction, this is a fixation on the quadriceps tendon. So you're looping the graft again through the midpoint and then through about making an incision about maybe between the medial and central thirds of the quadriceps tendon, and then folding it over and sewing it to itself, and then taking that suture and sewing it through the supermedial corner of the patella. Oh, this is just an example of how I perform this. So this incision is kind of at that midpoint that we just discussed. And then there's another incision about a centimeter long between the junction of the medial and middle thirds. And then this is passed in a partial thickness fashion. And the graft really doesn't need to be prepared here. I just make sure that it's under a six. Usually it's about a five, five. And for this, I use a looped suture to sew from a medial towards the patella. And then lastly, you can cut off the needle and take that stitch and really attach that to the supermedial corner of the patella, which is really similar to maybe what people do with a suture anchor right at that same location with cortical fixation. And then at the end, we just close that sort of the proximal aspects of the incision and the quadriceps tendon, just to prevent any sort of proximal propagation. So on the femoral side, when we're placing the femoral tunnel, we want to think about anatomy. So the first thing is you want to make sure you're distal to the adductor tubercle, always posterior to the medial epicondyle, and I'll place a pin there. And then once we confirm that we're anatomically in the right spot, then we'll check this on fluoroscopy. So for me, I like to be posterior to Chateau's point. The way I think about this is if we want to place a tunnel, and so for me, I use an eight millimeter tunnel, and I place the screw behind the graft. So you really want to make sure that this pin is where your graft is going to be, which means you have to cheat this a little bit more posterior. We want to make sure that we have at least four centimeters of the posterior cortex visible. And then finally, once we checked both the anatomy and the fluoroscopic views, we'll make sure that there are minimal length changes between zero and 60 degrees. So we generally accept less than five millimeters, but we try for even less, I would say one to two millimeters tops. Finally, for setting the length or tensioning as people refer to it, Jack Farr refers to this as setting the length because we're not really using the NPFL to pull the patella into position. We're really just bringing the knee into flexion and then removing the slack from the graft. I tend to do this at 60 degrees. Other people have described this at 30 degrees where you allow about half a quadrant of patellar mobility there, but I think that's a little bit harder to feel. At 60 degrees, the patella is really engaged in the patella, and so it can't really go anywhere. And so you can just remove the slack from there, and then I use a femoral fixation with an expanding anchor. This allows me to kind of check it, see if I like it before I deploy the anchor, and it also minimizes rotation and tightening of the graft when you use an interference screw. Over-tightening is a big problem and one of the most important complications that we want to avoid. It's important not to over-tension, and remember that there's only tension when the patella is laterally displaced, and over-tightening can lead to arthrosis and other types of problems including graft failure. So how do we avoid complications? Well, the indications are important. So this is performed in the setting of lateral patellar instability, not for patellofemoral pain, not for medial instability, so important to rule that out. It needs to be anatomic in order to minimize complications, and we have to make sure that we don't over-tighten the graft. The other important thing about soft tissue procedures is that it addresses only soft tissue deficiencies. So if there is malalignment in terms of tuberosity lateralization or patella alta or a large supratrochlear prominence, any of these things would need to be addressed at the same time as well. And the reason for this, we know that with every single anatomic risk factor, the length changes increase between range of motion. And so the goal with this reconstruction is to keep it isometric and to minimize length changes. And so this is why we want to address the additional morphologic risk factors with concurrent procedures. So in summary, soft tissue procedures for isolated soft tissue deficiencies, it's important to remember the anatomy for this and to consider MQTFL reconstruction as well. To avoid complications, the thermal tunnel is critical. So we want to avoid patella fracture, and we want to make sure that we don't over-tighten. And of course, we want to make sure that we address the bony or concurrent procedures for bony malalignment, patella alta, and trochlear dysplasia, which we're going to hear about in our subsequent talks. So I have one short case that we'll kind of go through. This is a case of a failed MPFL. So this is an 18-year-old male who was playing basketball, landed on another player's foot and sustained a patellar dislocation, which reduced spontaneously. He was seen at an outside hospital and treated initially conservatively, and then subsequently underwent MPFL reconstruction with allograft at another hospital. He had some difficulty regaining range of motion after his surgery. And then after returning to basketball, he re-dislocated in his first game back. Since then, he has had a couple more dislocations, the most recent being two weeks prior to presentation. And he feels functionally unstable, even just with non-sporting events and walking on uneven ground. And he reports some limited range of motion as well. So on examination, he had no fusion, well-heeled incisions, a little bit of quadriceps atrophy. Most importantly, he had two quadrants of medial mobility and three laterally with positive apprehension, indicating that he was unstable. He had some limitation in his range of motion as well, in terms of flexion. And the remainder of his examination was normal. So here are his radiographs. Overall, we're not seeing any sort of major malalignment. I'll show his long-leg alignment films in a second. No substantial patella alta. You can see the cortical irregularity along the medial facet of the patella, indicative of prior dislocations. If we take a closer look at the lateral, we can see his femoral tunnel here, which is pretty anterior. Here's his MRI. You can see that he has a little bit of an infusion. His cartilage looks good. The patellar fixation is a little low, but it's not penetrating the anterior cortex. And then on the sagittal, we can see that tunnel, again, looking a little anterior. TTTG distance on CT and full extension was 25 millimeters. And his alignment views looked good. I didn't draw the line here, but they were through the central thirds of both of his knees and symmetric. Lastly, I'll show the dynamic CT. So I make a big deal about this, especially when I'm assessing trochlear dysplasia. Obviously, in his case, he didn't have a lot of dysplasia, and so we're not expecting to see anything too interesting here. But this is one way that we're able to see maltracking. And we're also able to see if there's any sort of supratrochlear prominence or spur that's kind of pushing the patella out of the way. And so I tend to get these on patients prior to surgery. So here is his 3D reconstruction. This is a great way to kind of assess tunnels and assess the anatomy. And you can see, again, this is pretty anterior. We want to be about one centimeter distal to the adductor tubercle. Or if we wanted to use our radiographic markers, we'd kind of aim for where I put this marker here. So a little bit anterior. So when we're looking at failure, I typically kind of look for all of these things. So I'm looking at the surgical technique, I'm looking at the patellar position, looking at the femoral position, looking at what the graft tension was like. That's a little bit harder, because at that point, it's failed. We're also looking at the other risk factors that weren't addressed. So bony malalignment. Do they have an aversion? What's their TTTG distance? Are they in valgus? Do they have patella alta? Do they have a displacing supratubular prominence? So I've highlighted and read the things that I found to be issues in his case. So for his case, he underwent a revision MPFL reconstruction, but I performed an MQTFL reconstruction. This is a nice option, especially in revision cases, because you don't want to be putting too many tunnels into the patella. So this avoids having to put additional tunnels in the patella. But again, this has to be anatomic. I also did a TTO to correct his TTTG distance, and you'll hear more about that in the next talk. And you can see here where his new tunnel is. So the take-home message here, recreating the normal function of the MPFC is critical. You have to be anatomic, and you want to make sure that you address the anatomic risk factors. In the setting of failure, the things to check for are graft placement, graft tightness, the contributing morphologic risk factors, and the need for concurrent surgery. And I think that considering MQTFL for revisions is a great option to avoid patellar stress risers. Thanks very much for your attention. So next up, we have Dr. Hinkle, who's going to be talking about distal realignment and when to perform it. Good afternoon. Thank you for being here that late. All right, so I'm going to talk when and how to do distal realignments. So as Dr. Danakis mentioned, the most important things that we want to know about patellar instability. So we have the static bone structures that are giving stability, the passive, so the soft tissue stabilizers that she also talked about a lot, and the active with the musculature. So in order to have stability, you have to have good contact from the patella, and that's going to be given by the morphology of the patellofemoral joint and also about the alignment. When we're talking about the distal realignment, obviously, we're talking about the alignment, so that's what we're going to focus on here. So alignment, those are the main factors that we want to take a look. So coronal alignment, rotational alignment, the extensor mechanism alignment, and the stellar height. As far as the coronal alignment, we worry about the valgus. We also worry about the varus knees because those are associated with rotational malalignments. And in this study, they show that for each degree of increased valgus, you have a one millimeter increase in the TTTG distance. So that's showing that coronal alignment is influencing the Q angle or the lateral vector of the quad. And when you have external rotation of the tibia, that also increases the TTTG. So that shows that both the coronal alignment valgus knee and those patients with rotational malalignments of the whole leg are going to have increased quadriceps vector. The other thing we want to check is the patellar height. So when you have patella alta, the patella takes longer to engage in the trochlea. That decreases stability, decreases contact. And decreasing contact, you also increase pressure. So, as we saw, those, the coronal alignment, rotational alignment, and extensor mechanism alignment, they have a relationship to one another. The patellar height is a little bit more separate. So, when you're evaluating those three, you always need to look at those in combination. So, how we evaluate those in the physical exam, some of the things that I look at most, patellar tilt, when you have increased patellar tilt, patellar tilt is associated with trochlear dysplasia, and also with increased lateral quadriceps vector and malalignment. So, it's a marker for me for, to really look hard and see where I'm going to find those malalignment issues. So, this marker is for abnormality. On the stability, you want to do an extension, early flexion, and deep inflection. One of the goals of the TTO when you're distalizing is to get the patellar to engage earlier, so you need to know if that's actually going to happen. Some patients have trochlear dysplasia that goes more distal, and if the trochlea is flat or distally, it may never really engage. So, if you're thinking about trying to engage by distalizing, that's not really going to happen. So, you want to know if that is something that is going to be achieving your goal. Subluxation and extension, that shows that the quad is really pulling the patellar proximal and lateral, which shows that there is an increased quadriceps vector. The Q angle, I want to evaluate in extension, and also evaluate the tuberosity, sulcus angle in 90 degrees of flexion. If both of them are increased, then you have more room to medialize when there are lots of changes between the extension and the flexion. That shows that there's some knee rotation, and as the knee goes from extension to flexion, the tibia internally rotates and the tuberosity medializes. So in those patients, those changes can be really large. And if you medialize the tibial tuberosity inflection, you may be over medializing while you're correcting extension, you're causing a deformity inflection, which can be a problem. So as far as the rotational malalignment, those are just some tips on how to recognize that it's there. So if there is a symmetry of the medial and lateral femoral condyle in extension, the wing sign, if you have a superimposition of the medial spine and the lateral femoral condyle, and you have medial rotation, those kind of trigger us to think that there is a significant rotational malalignment. In those patients, you should order a CT of the whole limb to evaluate for those numbers. Those are the numbers that are more significant. This is not the topic of the talk, so I'm gonna assume that those were normal, and let's talk about the tuberosity. So we wanna evaluate the extensor mechanism. The most common measure that we do is the TTTG distance. This is really not good. So in this study, they show that the lateralization of the tibial tuberosity and the sulcus shift was not associated with the TTTG, and they were pretty normal compared to the controls in the patients with patellar instability. And the knee rotation was the main factor that was driven that TTTG to be increased, showing that the rotation is one of the main deformities here. Still, the knee rotation's not something that you can correct, so you wanna know that it's there, see if it's significant, but the only way that we can correct this overall alignment of the TTTG is in the tuberosity. So one of the measures that we can see if there is an actual deformity of the insertion of the tibial tuberosity within the tibia, one of the measures is the TTPCL. This is one of the first studies. There's a very small difference between patients with instability and patients who are controlled patients. And based on their numbers, the mean was 18.8, one standard deviation's four millimeters, so roughly 22.8, 23 millimeters should be an abnormal number. This is one of the angles that we described, so if you wanna have it all evaluated in one measure, you can do the tibial tuberosity angle, and that has been shown to be more associated with instability, and then you do all in one measure. And the other thing is that it's stable in patients with different size, so if you're evaluating a kid, that would be of benefit. Regarding patellar height, those are the main measurements that we use. So the trochlear empty sign, if you see the patella in one level, the trochlear in one level, and it's empty, that is a sign of patella alta. We all know about the coton de champs, the incel salvare. The other measure that I like to use is the tendon length. The main reason why the patella is alta is because the tendon is too long and not that the insertion is more proximal, so there are some things that can cause bias in the patellar height, so if I see a tendon that is long, I tend to believe that that measure that I'm doing is real and that the patella is really alta. So here, just some examples on how the engagement can change and change our evaluation. Those are two patients. You can see that in the patient on the right, the coton de champs is higher, but the patient has a better engagement. So those are some of the things that we want to notice. So in patients who are borderline, especially coton de champs between 1.2 and 1.4, I'm gonna look at that engagement. If the engagement is poor, I'm gonna think more about a TTO. If it's not, then I don't think we need to do it. Like I said, some biases can come, especially for the MRI. A lot of protocols, the knee have to be in flexion in order for them to use the coil and get a good image, so always check the knee flexion, the flexion. It's good to check in the axial views, too. If you see some good engagement in the axial view, then it's probably because the patella may be subluxated and it's not really at the trochlea, so it may be that they are not in contact because they are not in contact in the axial plane and not just the sagittal plane. And like I said, I like to check the tendon length. If it's abnormal, then I'm gonna think that that's a really good measure of the engagement. So just kind of getting all things together, things that I would say we would think more about a pro of doing a TTO would be patients who have a glide J sign, patients who have a reverse dynamic patella apprehension. That test is a test that you do with the, you go from patient inflection to extension while you're pushing the patella laterally. If they have apprehension in deeper flexion, then that is more associated with the bony abnormalities. Patients who have the patella tilt, increased stability with flexion. Like I said, you wanna make sure that there is increased engagement with flexion because you're kind of simulating that patella going down and the distalization. In patients who have valgus knees in which it's less of prejudice medializing the tuberosity because in patients who have various knees, if you increase even further the medial tibial femoral joint pressure, that can be detrimental for them. The imaging, we already talked about those numbers. So if you have an increased TTTG, and that is coming from the proximal tibia deformity and the lateral tuberosity with an increased TTPCL and a decrease in a not high knee rotation, that deformity is on the tibia. So it's preferred for a TTO versus someone who has an increased knee rotation in which you're creating deformity in the tibia in order to correct the overall alignments. Katonda-Shams, the engagement in the patella tendon length that we talked about. So the goal of the tibial tuberosity asthenotomy is to increase stability, increase tracking, and also to optimize the patella femoral reconstruction or the medial patella femoral concept like Dr. Tanaka just talked to us. When in patients who may have chiral adhesions or pain, that it's also very powerful for shifting the load. I like to call, I like to say shifting the load and not unloading because unloading is relative. You're shifting from lateral and distal to proximal and medial. It's just not disappearing. So unloading may be a little misleading in those terms. So why don't we do it in everybody? TTOs have complications, more complications than just an isolated MPFL. Numbers are all over the board. They can go from 5% to 20%. Some of them are gonna be minor. Some of them are gonna be just, I need to remove the screws, which doesn't cause that much problems for the patients, but some can be pretty severe. Fractures in the tibia, fractures of the shingle, non-unions, and things that can decrease the mobility and decrease the function. In terms of why would we do it, some studies have shown that when you have risk factors and you do an MPFL, for example, this one showed a tendency of worse outcomes when the TTTG was over 20. When you have, this other one is showing apprehension in patients who had an increased TTTG distance and this other one showed an improvement in outcomes in patients who had a TTO when they had an increased TTTG distance, showing the power of the TTO. Those two are just kind of testing algorithms. So if you use those thresholds that they use in the study, so cut on the chance between 1.2 and 1.4 and TTTG over 15 or 20, then you can have patients having the same outcomes with an isolated MPFL and no risk factors and if you corrected the risk factors. How to do it, this is a recent Delphi consensus that we did. So those are kind of the factors that we had strong consensus on what to do. So some of the pearls that came from that are all of those. I'm gonna go over some of those. So one of the things is try to preserve the distal hinge. This is one study that showed those in blue are the complication rates of fracture in non-union for those three types of distal cuts of the osteotomy. So if you do a step cut, their complication was 11.8. If you did a little bit of more of a slope was 6.2 and if you preserved the distal portion, it was almost zero. Now, when you're doing the destabilization, obviously you need to disrupt the distal cortex. So you have to choose one way to do it. I would say that instead of doing the step cut, doing an oblique cut would be a better option. The other thing is neurovascular damage. Some patients, a very small percentage of them are gonna have the artery that is gonna be close to the bone instead of being posterior to the popliteal. So I always check in the MRI preoperatively and put it in my note that that's not the case. Haven't seen one that has it. She saw one. So pay attention. And then the other thing is when the screws go from lateral to medial, you're going away from the neurovascular bundle. So if you're doing an EMC and you have an oblique cut, that is gonna be more favorable. How much would you do? So you wanna try to do enough to make stable. You don't wanna do more harm. Pay attention to the coronal alignment, especially the patients who have varied knees and irritation and all those changes from flexion to extension. Avoid over medialization. So what I try to do is I just set it in flexion at 90 degrees to a neutral angle. I don't want it to be medial inflection because that doesn't seem any point in time. In our function, that's what would happen in a normal person. Remember that when you're distalizing, the tibia crest goes medial. So if you're distalizing, if you're medializing just to match that contour. And for how much you're gonna distalize, NPFL scars the knee, open surgery scars the knee. So I try to get more to the 1.1. So at the end of the day, I'm gonna have something that is not gonna be causing patella barra. So for distalization, those would be my first things that I have changed in the last while. So if you're distalizing, most of the times people do a straight cut, like a 90 degrees. But actually, if you're distalizing, you can make that angle as the way you want it. You can still do a 45. You're distalizing. If you're not medializing, you're not worried about changing how much anteriorization, medialization you're doing. So you can still do a 45 degrees cut, which is gonna be better to protect the neurovascular bundle without causing any of those changes. I just continue, based on that study, I just continue oblique instead of doing a step cut. And the things that I like, the thing that I like the most about that is that then I have freedom to distalize how much I want. If you do the step cut, you already bought your distalization before actually seeing the effect that it's gonna have in the papilla, unless you keep trimming or you leave a gap, which none of those are ideal. So if you just continue the cut, you can distalize, look at the x-ray, and mark it as you want it, with the papilla height that you want. And then at the end, I just kind of trim the end off that little tip that goes anteriorly. It seems to me that may heal better a little bit distally. That's just kind of my personal perception. I don't have a real data to prove that for now. And then the other thing that I've been doing is adding a proximal bone substitute that I learned from Chairman, to give that support in the early phases, so there's not too much tension when the patient is doing flexion. So here's some pictures. Some of those pearls from the Delphi study. So I like to put all the pins at first so that when I'm putting in the screws, the tibia doesn't move. When you create the holes, it's gonna move a little bit, so if you have the other pins destabilizing, that's helpful. In the right picture, we have the substitute bone. And then here are some pictures. So this is a patient that I did the left knee first, and I did the step cut, and then in the right knee, I did that oblique cut. So it seems to me that the healing is just better in the distal portion, even though they both healed, and she's happy. Here are some patients a little bit longer. So the one in the left is 10 weeks, so already pretty much healed. And the other one is two years, so you can still see some of that bone substitute, but it looks like a pretty healthy bone in there. So here's one case. So I'm not gonna tell the whole story, but a 14-year-old male, recurrent patellar instability bilateral. So on the physical exam, he had neutral alignment. Patellar tilt was positive. Didn't have any signs of pain or cartilage problems. No swelling, no crepitus. Apprehension was positive. Reverse dynamic patellar apprehension was present in deflection. No end point of the MPFL. Severe lateral laxity. I could actually dislocate his patella. Not that I wanted, but it happened at 30 degrees, and subluxation in extension was positive. So here you can see the J sign. It kind of tells you a lot. It tells you if the patient has ALTA. It tells you if there is, you can see that change in extension and flexion for the Q angle and the tuberosity. Trochlear angle. So you can see that glide. So neutral alignment. Index where you can see some trochlear dysplasia, but didn't seem too bad. In the MRI. So next review, you can see the patella not engaged with the trochlear, a flat trochlear. You can see that the tendon's going over the lateral condyle, which also shows that there is a flat trochlear. There is increased lateral quad vector. Here's trochlear dysplasia. The engagement seemed okay. So this is kind of one example that if you look at the sagittal, you think that the engagement is reasonable. If you look at the axial, you see that clearly it's not. So those were his numbers. So an increased cut on the shunts. Trochlear dysplasia with the crossing sign and a bump, but the bump didn't seem that big. And in the x-rays, the subluxation, the tilt were normal, showing that his trochlear dip in deflection was contained in the patella. Increased TTTG. The TTPCL was borderline. The knee rotation was also borderline. So some of the deformity coming from the tibia, some from the knee rotation. The trochlear dysplasia was shallow, a little bit of bump. Increased subluxation, increased tilt. And then the other thing interesting of this case is he had open thysis. So I kind of felt that I could do it, but I wasn't that confident. I asked help of my pediatric IPSG friends. One thing that I did was I checked the bone age. And even though he was 14, his bone age was 17, which gives me a little bit more confidence. Another friend, Liza Irons, she said, check the slope. One of the concerns of the anterior tuberosity, thysis not being closed, would be that you can change the slope. So if the patient already has some slope, you may not be doing that much detriment if it closes a little earlier. And the other one tip that I got was check the estimated height based on the parent's height. And if that estimated height is not enough, if it's within five to 10 centimeters of the patient's current height, it's probably okay to do the osteotomy if it's almost closing. So for him, the reasons for TTO, he had abnormal tracking. His patella was out, his patellar tendon was long. He had the same tetrachlea, increased quad vector with mostly, with a lot of it coming from the proximal tibia and not for the knee rotation. So again, here, his pre-op. And then here, a more normal tracking in the post-op was just what we wanted to achieve. And that's what I have. Thank you. Next up, we have Dr. Seth Sherman from Stanford. He's gonna be talking about trochleoplasty. All right. Well, thanks for sticking it out with us. It's getting close to six o'clock and happy hours. And I have the controversial talk here, trochleoplasty, do or don't. Controversial here at Anna and probably mainstay across the pond at ESCA the same week, interestingly. My disclosures are available online. The biggest disclosure is that John Fulkerson is always watching. There he is. And John is really in tune with this particular topic. And it'll be interesting to get his thoughts and perspective later in the meeting. None of this is possible without trochlea mentors and also other contributors to both this talk and to my evolution of thought here. And obviously my co-panelists just for their expertise in patellofemoral in general. This is a confusing topic and hopefully I'm starting to simplify it in my own brain. And I can translate some of that to you guys here. The key points for any patellofemoral joint preservation is that this joint is an organ system. We must take care of all of the aspects of it and to be thoughtful and mindful of all of them. Obviously trochlea is a morphologic issue and part of the bony malalignment to the right. But dysplasia is really our elephant in the room. We know for sure that it is the driver or main driver of our risk of recurrent instability. And we also know for sure that it's a major contributor to patellofemoral arthritis. But the real issue is when do we actually get to or have to push that elephant? And the first point is that specific treatment of the trochlea is rare. I went to visit David Dejour. He gets every patient in his entire country coming with doctors who say that they need trochleoplasty. And he only does about 30 trochleoplasties per year. So that's a lot of trochleoplasties. That's two to three per month. But that's David Dejour turning down all of these trochleas and doing all the other things that our panelists are talking about. And before we can really treat rationally, we must recognize and classify. And this is our biggest problem. And I hope this year at IPSG, the patellofemoral meeting in Big Sky, we can really come together and try to continue to refine and work on the classification so we speak apples to apples and not oranges. We know we use x-rays, MRIs, CT scans. We all have seen and wrestled with the Dejour classification. And, you know, I think for me at least, this starts in the clinic with a well-done lateral x-ray. If you can't read laterals, you can't do patellofemoral instability work. And so that's not a perfect lateral. This was, I think, David Deduck's lateral. But he points out the key elements here. So you can see kind of the depth of the groove in the dotted blue. You can see the condylar line in the red. And then we can see that super trochlear spur in the green. And so we must recognize if these things are present or not present. We can also see if there's a double contour line, as you can tell in that picture. One of the main aspects of this is anterior prominence of the trochlea. So on that lateral, on either your central cut of your MRI or your lateral of your x-ray, you can draw a line down the anterior cortex and look at how much bone or how much trochlea is anterior to the anterior cortical line. For those who do PF arthroplasties or regular arthroplasties or just in general, we want a smooth entrance. And if you have so much bone, it's like a ski mogul that's just pushing your patella off to the wrong direction. We also need to be mindful about the length of the trochlea. Basically, shorter trochleas with these crossing signs that are more distal with larger spurs and anterior prominence are the bad actors. We start to do some pattern recognitions. It's getting kind of late here. I might just do raise of hands here. So let's just do this very quickly to get some participation. So let's call these normal, low-grade or high-grade. Let's not go to du jour. So the one on the left, raise your hand if you think that's normal. Okay, raise your hand if you think that that's low-grade dysplasia or high-grade dysplasia. So interestingly, I don't have a pointer, but the one on the left, you can see that it does have a crossing sign, but it's a long trochlea. The anterior cortical line is flush with the crossing sign. So that is dysplasia. It's just a very mild dysplasia. In interest of time, the middle one is completely 100% normal X-ray. And then the one on the right has some of these features, again, repetitive of dysplasia. This has that crossing sign. You can see a supratrochlear spur. And you may argue that you also see that double contour. In looking at these, a couple of them are a little more severe grades of dysplasia. So if you look at the middle one, you see that the crossing sign is pretty close to the anterior cortex. There's definitely a spur. So that's a form of dysplasia. We may call this a B if we're using the du jour. And then the one on the right has that big anterior prominence. It has, again, all the features. It has a crossing sign. It has a supratrochlear spur, et cetera. So we don't all agree on this. And we could spend the whole time doing this. But if we can't agree on that, then we should really be cautious before we start doing a ton of trochleoplasties. And so this is a critical point. It has nothing to do with the merchant view at 45. I mean, this is the same knee. That's a merchant view that's normal. So the dysplasia doesn't run deep in this one. But that is an egg-shaped trochlea. That is a severe, convex trochlea at the proximal entrance where it matters the most. And so it's really more about some of those other features and not just the merchant view. We all know that isolated MPFCs are a great operation, even in the setting of trochlear dysplasia. And so it begs the question, when do we ever consider doing more? And to really summarize, these are a little different J-signs than what Bettina showed, which was gliding. These are the jumping J-signs. And these have combined instability patterns, rotational, and severe amounts of trochlear dysplasia. So if you're seeing these patients, I think everybody in the room will agree not to just do an MPFL. But I think this is when we really start thinking about doing more. The other pearl here, as Bettina did touch on, the apprehension and deep reflection. I mean, this is an operative patient that's dislocating well into flexion. But in the clinic, we can do that moving stress test as well. And those are also the bad actors. There's a lot of do more here. And we're obviously going to focus on the trochlea. All of this has to do with thoughtful pre-surgical planning. And these are all of the things that I think about before acting. And there's a lot of force vectors that we have to consider. There's morphologic features. There's cartilage, subchondral bone, and the patient, and about 15 other things. And so that's the things that we think about every time. These are some of the measurements that at least we get clinically and or with our imaging every single time. And then we make thoughtful plans. And so when do I consider a true deepening trochleoplasty? The right patient for me is one that's a really high risk, failed prior surgery in a lot of cases, that major jumping J sign, apprehension into flexion as well. And so you can see the right imaging here. So that major anterior prominence, that boss height or prominence greater than 7 millimeters in general, and the convex dysplasia, the egg-shaped dysplasia as you see there. And then importantly, that it cannot be effectively unloaded or stabilized in any other appreciable way. And so a lot of Americans never do trochleoplasties and can contain these patellas with AMZs and or distalizations, or as we'll see examples of with OCAs and PFJs in the right cases. So these have dysplasia, but they're just treated with different tools. There are different techniques. This is the technique that I watched David DeJour do. I don't know if we can hear him, but he basically cuts the cartilage. And I'm a cartilage surgeon, and I don't love necessarily cutting right through the cartilage with a blade and recontouring it, but obviously he has probably the biggest experience in the world with this type of surgery. Myself and others in America who are doing this, I think, have caught on more so to the thin flap trochleoplasty, which can be open for me now or arthroscopic. And I was very lucky to have Martin Lind, who's chairing ESCA, with me for a month. Martin has done many, many trochleoplasties, a very experienced surgeon. He watched me try to do one. Then we went to the lab, and then I somehow had another one on during his month there. I don't do that many in a year, but I happen to have complex patients. And so, you know, I kind of learned some of these principles from him. What I just showed was that anterior prominence, or boss height, this one was a centimeter. So there's a centimeter drop-off to get to the anterior cortex. The first thing that I do, and the only thing Martin does, is actually use this curved osteotome. So he does the whole operation just with the curved osteotome. You saw me outline initially and reflect the synovium. We go all the way down on either side to the level of the top of the notch. And so I basically enter deep to the cartilage with a pretty thick flap using those osteotomes. And then I switch to this five millimeter guide. And the goal is to try to make this malleable, as you see here. So we carefully, our malleable, we lift up the trochlea with the bone underneath it. And then I can use a high-speed burr and start to do a little bit of artistry. We want to move the groove center from medial to more central. And we also can actually create an inclination. So we can recreate or restore what is a normal shape of a trochlea, whereas before we had the convexity. I think when I started doing this, I wasn't thinning flaps enough, and I was very happy just taking out bone and going flush to the anterior cortex. And that solves a lot of these shape problems. But as I'm getting more experience, I can make that flap more malleable, and I actually can recreate actually a groove. And I think that contouring of the bone deep is a big part of that journey. Here you can see these are basically just vicral sutures and peak anchors and thumb pressure to go from convex to concave. And then usually we bone graft laterally. So you don't have to bone graft medially in most cases. And we definitely don't want to take down cortex lateral because you're building up that lateral side. So you want to make your inclination better, but not take cortex. And so that's kind of the type of shape that I can get these days. Clinical outcomes, I mean, they're out there. There are not many and not many high quality studies, but they do exist. These are all case series, not kind of comparative series. In general, this 97% mild OA at 15 years is reassuring. Kujala scores up by 30 at four years is reassuring. D-Duck had 81% returning to sport, also reassuring. This is one of Dave's. So you can basically see the difference on the x-ray. So you start to appreciate these shapes and the differences and what we can affect change on. And then you can see his merchant view as well, which did change a little bit in this particular case. And he needed a second look probably for stiffness as he did have some stiffness issues in his early experience. But what he was trying to point out here is that the cartilage surface is quite well maintained. And so what about combining a deepening trochleoplasty with patella cartilage restoration? Well, sounds fine. There's absolutely no data to support this. It needs further study. We're seeing these patients, but when and how do we do them? I think, I don't know if you were on this paper as well, Andreas's paper, looking at Macy's in the setting of trochlear dysplasia, and they did fine. So again, gives us room to pause and reflect. Does trochleoplasty actually unload patella chondrosis? It stands to reason to me that maybe it does. Jason co-looked at this in the lab. He found clearly it helps to stabilize, but maybe at the detriment of patellofemoral contact pressure. So again, another, certainly not a home run in the path of major rapid adoption of trochleoplasty. I have patients like this. So this is a young active patient, convex trochlea and chondrosis. So that one I'm treating with basically a different type of trochleoplasty. I'm putting in an OCA to become a trochlea. And so that's another variant on the same theme. This kind of patient, older, more sedentary, severe dysplasia and arthrosis, gets another kind of trochlea with metal and a plastic patella to boot. And so another emerging concept here that shouldn't be overlooked is this entrance trochleoplasty, the Peterson grooveplasty. So this is a patient that might benefit a supratrochlear spur, a large J sign, that long trochlea with a high crossing sign that's pretty flush to the anterior cortex. So not a huge anterior prominence. And basically we can just lap it off. You see the black there just contouring the bone so that you have a smooth entrance. That takes about two minutes if you're open for other reasons. It's super easy. It's not very morbid. It's basically akin to just grooming a trail. And the challenge is that we don't have a ton of data on this. If we look at grooveplasty versus trochleoplasty, Mario Havisi looked at this in the Mayo series, and they're pretty much equivalent. But I still think the things that I define for my entrances versus deepenings are not widely accepted. That's just how I've come to conceptualize this. I need to back that up with my selections, and we need to probably validate that further. But that's kind of how they did that. I guess in the interest of time, I think I'm gonna close. But my last point here is that I'm trying to evolve and think about trochlear dysplasia and when I need to add it for severe dysplasia and then do soft tissue balancing. And at least in my evolution, I have not been able to ignore the other force vector problem. So I need to keep using TTOs. I need to derotate in those rare, severe cases. Or I'm not balancing patellas. And when I do my range of motion in the OR, my TT sulcus angles are off and the patella is dislocating before it even gets to 30 and 60. So I feel like I'm at the beginning or at the end of the beginning of my trochlear journey. I'm seeing this. I think I can classify it. And I'm trying to still be very careful in who I select this in. And I think that my stance on this will change yearly, probably for the next, well, maybe forever, but at least till I get to a steady state over the next five years. And thank you very much for your attention. Thank you. Thanks. Thanks, Seth. Last but not least, we have Dr. Sabrina Strickland from HSS. She's gonna be talking about how to address cartilage and during the teleformal instability. So truly, thanks for sticking around. And just like the previous talks, I wish I could have a completely simple, clear algorithm. I do have some disclosures that may relate a little bit to this talk. So first of all, cartilage loss is really hard to tell from X-ray. And I would advise, if you see any instability patient, to have a super low threshold to repeat the MRI or of course get an MRI in the first place because you certainly may miss a chronic overload type of chondral loss, which you see on this left image, or cystic changes in the bone where you can certainly lose loose fragments. I would love for this slide to advance. Yeah. Okay, there it goes. And not everybody with pathology needs surgery. So here, this patient has a clear cartilage problem, but she ran the New York City Marathon a couple of months before I saw her. So as patients get older, it's not that I treat every patient with a cartilage problem in the patellofemoral joint. I may treat the instability. You have to look at why there's a cartilage injury. We're talking about instability, but there are patients who have a sheer injury like this MRI, but there's other patients that are overloaders. So you may see medial facet loss or you may see lateral facet loss depending on their alignment and how chronic this is. I also happen to see a lot of cartilage injury from bad previous surgery. So misplaced tunnels, as Miho talked about, potentially an over-medialized TTO with medial chondral loss. The treatment algorithm for cartilage repair is the standard for as with any cartilage repair discussion. There are small lesions, especially inframedial patella or anterior aspect of the lateral femoral condyle that you can treat with just a simple debridement or very small lesions. A repair, especially if it's a fresh shear injury with bone on the back of the fragment, you can treat that with suture and just tie those sutures over the back of the patella. That's super cheap or absorbable nails on the femur. I personally never use microfracture for patellofemoral cartilage lesions. I think even if you get some good fill, it doesn't last very long. Osteochondral autograft, I think it's a rare, rare indication to use that in the patellofemoral joint. Taking cartilage from the trochlea and moving it to the patella just doesn't make sense for me and I end up doing a fair amount of revisions for these cases. What about chondral allograft? There's DeNovo, which is, at least at HSS, just under $5,000 a packet. We have it on the shelf, so I think something like DeNovo or Cardimax is good if you have no other options, but I don't think we have good long-term data and insurance never covers it unless you lie and say it's an allograft and it's not. It's just a cartilage. It's not an osteochondral allograft, which is pretty much every single insurance policy specifically states that they do not cover DeNovo, so I would be careful about billing them for that. MACI, MACI I think is a great option for the patellofemoral joint. It's just expensive and requires some approval in advance because patients are certainly not willing to pay out $55,000 on their own dime. And then osteochondral allograft, a trochlea, costs just under $12,000. I don't expect you to read this slide. I just put it on there because there's just not a ton of studies on specific cartilage treatment for the patella. We're certainly trying to add to this data with our experience at HSS, or at least I work with my husband, so we share our research staff. But we have been looking at things that we sort of alluded to already, like does the shape of the patella matter? And at least we've shown that the Weiberg type doesn't matter. It does matter when you're trying to match a patella because part of the problem with patellofemoral research is that the cadavers tend to not be dysplastic, same thing with the donors. And so it is a more tricky surgery than doing just an osteochondral allograft for a condyle. So debride only, which defects are these? The inferior medial patella, these small lesions. You can see here it's peeling off in the bottom right image. It was just a shear injury. Those do quite well if you just clean them up. Once it starts getting into the weight-bearing zone, I would recommend fixing them. Large pieces with intact cartilage. You can see here with four absorbable nails. This was a smart nail. Pete Fabricant, who's a pediatric sports surgeon at HSS, showed in young patients with an average age of 12 with cartilage-only defects that they were able to secure them with absorbable darts and actually had excellent outcomes. I would advise this is a better treatment for patients with the open growth plates. Mosaicplasty, I love this. I love this slide. I've had the same slide for years because I don't think anyone really does it anymore. At HSS, they had a 71% flush appearance. I always use the analogy if you had your bathroom tiled and the tiler got 71% of the tiles flushed, you wouldn't be very happy with the tile job. So again, I don't think this is a great option. What about this perforated allograft cartilage? This is a product, an Arthrex product. I mean, the potential advantages sounded great. It's malleable, it's off the shelf, it's perforated. My experience is about 50-50. I tend to, and this picture, these images were actually sent to me by one of our former fellows who thought he was gonna be able to repair an acute shear. And then it was fragmented when he got in there. And so the only option he had was something, was at his institution, Cardiform. Juvenile particulated cartilage, there's a number of studies, but as you can see, they all have fairly short-term outcome, 30 months, six months, 26 months. So there's not a ton of data for DeNova. I tend to use this if it's a small lesion or if there's a surprise, or I think there might be a surprise, I can reserve it because it just sits at room temperature on the shelf. It is fairly expensive. As I mentioned, insurance doesn't cover it. And I treat these much more conservatively than an OCA. What about Macy? I think Macy's a great option. It's really easy. I think technically it's the easiest surgery we have for cartilage. Generally, you want a fairly contained defect. If it's not completely contained, like a superior lateral trochlea, you can make small little far lateral drill holes and sew it in on that lateral aspect. One facet, I cross the median ridge all the time. Cartilage-only defects, if there's some small cysts in the bone, I think you can ignore them, especially in the patella. Cost and insurance approval has gotten much easier over the past few years. It was an issue and a fight with UnitedHealthcare. Now they approve it for the patella. It is two surgeries, but I do like the fact that you are forced to do a staging scope because I think we find that lesions tend to be larger than the MRI shows. It is a long recovery. I don't let patients go back to impact sports for nine months. Outcomes, a number of studies. We have 10-year outcome in Australia, as well as Europe. It's only been the United States for six years. But overall, 64% good and excellent. 92% would do it again. Less than 10% failures in Jack Farr's group. And I think maybe the most impressive study was 78% of Army personnel returning to their occupational specialty. So for those of you who have not done MACE, comes on, I tell patients, comes on a little membrane, looks like a paper towel. They came up with these cookie cutters a few years ago, which make the surgery incredibly easy. My PA can cut it on the back table. This patella on this video looks like there wasn't a problem, but there was a significant cartilage flap, I promise. And here, you just have to be really careful not to cause any bony bleeding. You do not want to go through that subchondral bone. You'll get an intralesional osteophyte. And this one actually has good borders, but in many cases in the patella, you could just keep going. So I think you have to accept that you're growing new cartilage. It's not going to be as good as new. So leaving some suboptimal cartilage to allow a good border, I think, is good. Osteochondral allograft, these are technically difficult, as I mentioned, just because of the shape. Here's a bipolar allograft. You can see a large allograft in the patella on the left and a large allograft on the trochlea on the right. I think this patient would have been a fantastic candidate for a PFJ, but she was 27. I think that's a good bailout if it doesn't heal well. I tend to sex match them, which makes it harder to get them, and it's really hard to get female patellas, but I managed to do that. Generally, I don't use a shell graft. I'd much rather use a large plug. Brian Cole has shown at Rush that that is preferable in a study with Jack Barr. And Bill Bugbee's group has incredible outcomes, 27 patients with 89% satisfied or extremely satisfied. We hope to publish something similar pretty soon. So this is a pretty classic case, an 18-year-old male. He plays lacrosse and football, had three patellar dislocations. What's so interesting, and I see this every day in my clinic, is that he had two years of his knee giving out. So I don't really, I'm not a big believer in the subtle instability. I think most patients know when their patella's unstable, but he was diagnosed with a bone bruise, and then he went for a second opinion, and they diagnosed him with a bruising on the underside of his patella. So he got a more specific bone bruise diagnosis. He went for a repeat MRI, and they told him he had a severe bone bruise. Three MRIs and three different diagnoses of bone bruise. And then a local physical therapist, sorry, I'm missing the T, but diagnosed patella alta. So they were a little bit closer to getting on track. Senior year, he had several hyperextension injuries and still nobody had noticed that he actually had patellar instability. Pain with stairs and squats. TTTG was 23, full thickness cartilage defect, patella alta. So I did a Macy biopsy. You can see full thickness fissure, but that was a flap. There was a small loose body. So essentially he was treated with an MPFL. I personally always use an allograft. TTO, and we could talk about TTOs for hours here, but 30 degree shingle, because I actually want to medialize him. I think enterizing him is good at the same time, but if you want to have a significant correction, you need to make a lower degree shingle. I got into his knee by a lateral lengthening approach. A lot of these patients, you even say anything about lateral, they get all nervous because a lot of them have had a lateral release that did not work well. You have to get into the knee somehow. And a 20 by 13 Macy. Here you can see interop images. I did not distalize his tubercle, but I do that quite often. And then here is six month MRI and second look at, I took out his tibial tubercle screws, and you can see this was actually looking really good at six months. A lot of times at six months, it'll look a little bit soft. This was actually quite firm at six months, and you can see good signal on MRI. We make it our standard of care that essentially every cartilage transplant gets an MRI at six months, if at all possible, which has been really nice because you get to see that OCA's still have a fair amount of edema and they're still doing well. Used to be we only imaged the ones that weren't doing well. And then for Macy, you see that the signal improves over time. So you may be bright signal at six months, but if you repeat the imaging for whatever reason at a year and two years, that normalizes. Here, are we out of time? We have a minute? Yeah, I think we're a few minutes over, but we started late. Here is a 25 year old female. She had a history of patella femoral pain. She was skiing in moguls in Park City, felt a pop, buckled and fell. Diagnosed in the clinic as a patellar dislocation with a large hemarthrosis. We aspirated 50 cc's of blood. MRI, you can see that fragment sitting just off the medial facet of her patella, but you can also see this large lateral condyle weight bearing lesion. So what did I do? I actually showed this image before, but I tacked the piece back down. I thought it looked great. You may have to trim these lesions, but then a year later, she presented with clicking. Hollis Potter at HSS said this MRI looks great, but I scoped her because she was feeling increasing clicking and when I did the scope, I essentially could lift off that whole fragment, so I had to stage her for a revision with an OCA. So I would say this is a good operation for a young patient and this is a pretty young patient, but in hindsight, I would have treated this with either a MACE or an OCA primarily. Thank you very much and hopefully we have time for some questions. Thank you. Thank you so much. Unfortunately, we're out of time, so if you do have questions, please feel free to come up to the front to ask any questions. For those of you who are interested in the topic, there is an online course that we've all been faculty for hosted by the Patella Pharma Foundation. This can be found at www.patellafarma.org. And lastly, thank you so much for staying and I apologize for starting so late and one last round of applause for our faculty. Thank you so much. No.

patellar instability

anatomic reconstructions

soft tissue

bony restraints

alignment issues

MPFL reconstruction

MQTFL reconstruction

distal realignment surgeries

coronal alignment

extensor mechanism alignment

patellar height