So the next session is patellofemoral with moderators Corey Edgar and Jocelyn Wittstein. So we'll go ahead and bring all the panelists up here if we can as well and get that started. Thank you. Thank you for your attention. We'll try to just touch some topics on risk factors and my preoperative thoughts. I have no conflicts with this to declare I'm a consultant and others are listed in the program. As likely everybody here knows, we do have a seminal anatomic study done by the Leonaese group that looked at anatomic risk factors associated with recurrent patella dislocations. And they were trochlea dysplasia, patella alta, abnormal lateral tilt, and excessive lateralization of the tibial tubercle as evidenced by TTTG. And the Leonaese group coined the term amenuella cart where each one of these factors was surgically corrected. And they had a very large series and very good results with 216 patients and 1% recurrence. The question really that we face today is that this was without an MPFL. And so everybody is questioning the menu. And do we have to have the same thresholds? And are all of them important to correct? We do know that the MPFL, the queen of the patellofemoral joint, is the major lateral stabilizer of the patella against lateral translation, major medial stabilizer against lateral translation. And indeed, its reconstruction is a cornerstone of nearly all patella stabilizing procedures. So the problem becomes is we know what people look like if they have a primary or recurrent patella dislocation. The problem is we don't know when these factors have to be corrected. Do they all have to be corrected? And probably most important for today's thought process is at what surgical threshold for best results. Now the conundrum is that we have insufficient powered literature. Part of this is because we're pretty good at it and we do not have a lot of failures. But we do have evolving data on fringe risk variables such as axial and coronal plane alignment. Many of the variables are continuous, not dichotomous. And so it's really hard when you have this continuous spectrum. And the number of variables in each person is often more than one. And so this makes all of our problems difficult. And truly, we need individualized treatment. That may be true for everything we've heard today, but I certainly think this is true in the patella femoral joint. So some of the important preoperative checklists, certainly not meant to be comprehensive, is to rehabilitate body movement patterns and understand, analyze, and document patella instability factors. This has to be part of your clinical note. Best surgery to accomplish best patella stabilization. I want you all to remember that we do have faulty body movement patterns. This is certainly very common, this functional valgus knee in the ACL population. It's also endemic in the patella femoral population. But I also want to turn your attention to sagittal plane malalignment, where they really don't engage their hip musculature. These are really poor squat mechanics, that patella is going anterior over the toes, and this hurts. If you tried to do this, you would be saying, ow. Your patella femoral joint would be saying, ow. So this is just a really quick case. This was a 13-year-old boy, BMI 28. He had a recurrent patella dislocation, a unilateral J sign, patella mobility consistent with patella instability. And on imaging, he had genuvalgum, he had patella alta, and he had a high TTTG. But in addition to this, we did a dynamic movement screen, and he had everything all over the place. Hyperextension of the knee in stance phase, dropped his pelvis, had adduction of the femur, et cetera. So how do you approach a person like this? So what we did is that we consulted with Peds and decided on guided growth, and during that time, we had physical therapy for improvement of body movement patterns, fitness plan and dietary considerations, and he was able to do some select sports with a brace. The point about this is that you need to individualize the treatment, and don't forget about trying to participate in all these other factors to get the best surgical outcome. So what about coronal plane malalignment? It almost always is a valgus issue. We do not…it's rarer to treat valgus in an adult for patella instability unless you have lateral tibial femoral joint at risk for a variety of reasons. But for kids, I think we need to consider guided growth more often, and if they have greater than two years of growth left, that is a preferred method. And we do not have any kind of threshold for this valgus alignment in an adult, and this is still more to come. What about other risk factors? I just want to say a few things about TTTG and patella height, two of the more common ones that we look at. TTTG, what makes up that measurement? Number one, lateralization of the tibial tubercle on the tibia. We do have a number. We can look for this. Two, rotation between the femur and tibia. We've known about this in the literature. These are two studies that had this. It wasn't specifically reporting on it, but this was in their results. And we do know that this is a new kid on the block, and that patella femoral people have more rotation between the tibia and femur. And then lastly, with high-grade dysplasia, we know that that central trochlear goes up, the sulcus is moved medial, and so you may have a high TTTG, but it's really because of the medialization of the sulcus. The point of this is that we have to reconsider what that TTTG number is, and maybe not be so quick to correct it when you see it just as a single number. We have to dissect it out. What about patella height? We all know that the sagittal plane, tibial-based heights, nice numbers, nice measurements, but what happens when you have something with abnormal anatomy here? You've got a long nose. You've got a reasonable incel-salvati ratio and not a very good canton-de-champs ratio. So we can't use this algorithmic one-size-treats-all when you're going to a femoral-based measurement such as patella trochlear index, which Jackie will talk about more. That does help, but oftentimes the patella's not in front of the femur. So just a clinical example about how my thought process might go. So here we have somebody that has a high normal canton-de-champs, patella alta with incel-salvati, on axial view at 20 degrees, has a shallow sulcus. According to the MR, they have nearly zero patella trochlear index, nearly no overlap. And I like to look at the axial view for a qualitative measurement. I call it the empty sulcus sign. You're looking up where the sulcus is there. You don't see a patella. You just see the patella tendon. But then in the operating room, I try to mimic the quads by grabbing onto the patella and looking to see what kind of engagement. So all of these criterias help me to say this person needs a distalization. So I just wanted to say that it's not so easy to just hang your hat on one number. What about torsion? It's definitely the new kid on the block, when to derotate and at what numerical threshold. I will say that we are recognizing that femoral derotation, that high anaversion has a role to play in J signs and probably external tibial torsion more of a role to play in pain. So in summary, imaging is an essential preoperative and interoperative tool. The surgical algorithm is fluid. Specifically, we need to pay attention to anatomic imaging factors and individual patient factors. The menu has morphed as we continue to learn. Thank you for your attention. We're still trying to seek the holy grail. Thank you. Our next speaker is Dr. Meho Tanaka. Thanks very much, especially to the program chairs, Mary and Brian, for the opportunity to give this talk and for assigning me this cute title and also for squeezing my one-hour talk into six minutes. So I'll be talking about soft tissue in the patellofemoral joint. So I think we all know about the MPFL and how this has been described as the primary static restraint to lateral patellar translation. We also know now that anatomic reconstruction is critical in avoiding complications. The anatomy as we know it has been changing. We've gone from the MPFL to the MQTFL and now the medial patellofemoral complex. So let's talk a little bit about what to reconstruct and why. The anterior attachment of the MPFL used to be thought of as on the proximal half or proximal two-thirds of the patella. But more recent studies over the past 10 years have shown consistently that there are fibers that attach to the quadriceps tendon as well, as can be seen in this photo, which is an interarticular photo looking at the extensor mechanism. John Fulkerson described these fibers as the MQTFL, as an attachment of distinct fibers proximal to the MPFL, and of course he described a reconstruction technique that avoids patellar fixation and essentially eliminates the risk of patella fracture. Subsequent studies have looked at where the exact attachment is, and we now know that the attachment is variable. So they have a common origin on the femur, so it's one ligament, but that some have attachments just to the patella, and others have attachments just to the quadriceps tendon, and the majority have an attachment to both. This is an example of an attachment that's just to the quadriceps tendon, as can be seen here. So then the question becomes, with this broad and variable attachment, where do we place our graphs if we're using a single bundle reconstruction? And so this is when we introduced the concept of medial patellofemoral complex to allow for the variability in attachment sites for a single ligament. And what we found was that the midpoint of this was consistently at the junction of the medial quadriceps tendon, where it meets the patella. So this means that for reconstruction, you can actually place the graft on either structure. On the femoral side, this has been talked about a lot. We know that the attachment on the femur is longer than it is wide. It's always posterior to the medial epicondyle, distal to the adductor tubercle, and there's usually a sulcus that you can feel in between the two structures where this originates. Now, this is important because we know that even six millimeters of malpositioning can lead to increased patellofemoral contact stresses, and the most common errors that we see are that the tunnel is too anterior and or too proximal. Now this can be difficult to find using anatomic landmarks. A lot of these patients have some sort of dysplasia or hypoplasia, and so using fluoroscopy at the time of surgery can be helpful. Shottle has described the point as being along the posterior cortical line and distal to the posterior condylar line. Corey Edgar, who is sitting next to me, has shown that you need a perfect lateral in order to be able to rely on this mark. But I think the consensus now is that it's not just one point that we're looking for. It's more likely a cloud, and I think it's also important to note that with this broad attachment, there is some difference between the most proximal and distal fibers. So I think in addition to that, checking the isometry of the graft at the time of reconstruction is critical. When it comes to reconstruction techniques, if you decide to fix this on the patella, there are multiple options. You can use anchors. You can dock this. You can use suture fixation. And the systematic review out of Mayo actually compared cortical fixation, so meaning suture or suture anchors, with bony sockets and found that there was no difference in terms of re-dislocation rates or patient outcomes, although there were greater complication rates in the cases that used bone tunnels. Patella fracture after an MPFL reconstruction is one of the most catastrophic complications that we can see. Ways to avoid this, drilling transversely all the way across the patella, avoiding double or large tunnels, and Amanda Wan's biomechanical study showed that it's really a violation of the anterior cortex on the tension side of the patella, which puts the patella at risk for fracture. If you're doing an MQTFL reconstruction, then this is a suture fixation, so you make a slot on the patellar quadriceps tendon and then secure the graft to this. The one thing I want to point out with this is that it's, again, at the junction of the quad tendon and the patella. It's not way up, so it's not above the patella, but it's really at that site. And this is nice because it avoids patellar fixation. Now, when it comes to graft options, you can use hamstring autograft. You can use allograft. Really no difference between the two in terms of recurrent instability or patient outcomes. You can even use the quadriceps tendon. Christian Fink described leaving this attached on the superior medial patella, swinging it over and securing it on the femur, which is a nice technique as well. And finally, a combined technique using MPFL and MQTFL. This is Min Kokur's group describing this technique showing return to sports of 77% at a mean of just under six months. Lots of options with this. All have good reported outcomes. No direct comparative studies clinically that I know of yet. Mechanically, Adam Yankee's work has shown that the MQTFL has maybe a little more function and extension. Vicente Sanchi-Salvanzo's study has shown that maybe dynamic fixation, so fixation on soft tissue, might be a little more physiologic than bony fixation, but really further studies are needed to determine the functional and clinical significance of these techniques. Regardless of which technique you use, I think avoiding over-tensioning is critical. So the MPFC develops tension when the patella is laterally displaced, so we're not tensioning or moving the patella with this, and Jack Farr describes this as setting the length of the MPFC, and we know that over-tightening can lead to arthrosis. My last few slides on lateral retinaculum, just to remember that the lateral retinaculum does have a posturizing vector on the patella, so it does add to stability. So currently there are no indications for isolated lateral release in the treatment of patellar instability, and there are some indications in conjunction with other procedures, but the trade-off is stability versus offloading. The indications in my practice are an over-tight lateral retinaculum, meaning you can't reduce the patella to the joint. If you do perform this, you should avoid proximal extension into the vastus, distal extensions to the lateral patella tibial ligament, which can lead to instability, and you can consider lengthening to serve as a restraint. So in summary, the understanding of MPFC anatomy and reconstruction techniques continues to evolve, and there are multiple techniques, all with good outcomes. Regardless of the technique, avoiding complications involves having the appropriate indications. So this is for instability and not pain, having an anatomically correct reconstruction, having the appropriate graft tension or length, and then adding the concurrent procedures that are needed, which is what our subsequent talks are going to be talking about, and also to respect the role of the lateral retinaculum in patellar instability. Thanks very much. Thank you, and next we have Dr. Jackie Brady speaking on when and how to add a TTO. Great. Thank you so much, and kudos to the course chairs for your very excellent titles. I think I got the best one. So I'm here to talk about when and how to add a tubercle osteotomy. Let's talk first about the when. So malalignment in the setting of instability and overload in the setting of pain, and sometimes you have both, and you have an opportunity to provide dual benefit. So malalignment in the coronal plane is basically the concept of, does your extensor mechanism have to turn a corner to get to its attachment? And in the sagittal plane, if your patella is so high-riding that you need an incredible arc of flexion to get into the bony confines of the trochlea, then your MPFL or your MQTFL or your soft tissue reconstruction procedure is going to be at risk. Basically, if you want or hope or plan to have your soft tissue work pull the patella back into the groove, then we worry that it's doomed to fail, and that's when we think about moving the tubercle. There's the ulta there. So TTDG is one way to measure coronal plane malalignment, and Dr. Arndt gave us a great heads up on that, that it's not pure, it's not a cutoff. It's been described as a cutoff of 15 millimeters, 20 millimeters. I spent a lot of time looking at MRIs and shown that it's more sensitive than TTPCL, which I'll show you in a minute, to differentiate dislocators from non-dislocators, but we really think that these anatomical factors are additive or synergistic. TTPCL is a pure lateralization of the tubercle on the tibia. So TTDG crosses the knee joint, and we think that matters because of the dynamic rotation of the tibia under the femur. Neppl showed us that that's increased in patella femoral dislocators, and we think that's maybe why TTPCL isn't quite as much of a differentiator. But the new kid on the block is this PTLTR, so the axial width of the patellar tendon that is lateral to the lateral trochlear ridge. And this has been shown to be more specific than the TTTG in differentiating dislocators, so a good one to have in your armamentarium. The A patient on the left there is not a dislocator, and you can see that patellar tendon is nicely centralized. And then on the right there is a patellar dislocator, and you can see that overhang over that lateral trochlear ridge there. So patella alta can be measured in a few ways, and we've had hints of that as well. Katanda shamp is our favorite one. It does not measure to the tubercle, so we can tell what we did if we move the tubercle. That's the important difference between that and the insole cell body. The modified insole cell body allows you to ignore any long patellar nose that the patient might have. And as much as we would like to ignore it because it does measure to the tubercle, it keeps turning up as predictive in our studies, and so it can't be ignored. And then that patellar trochlear index is an MRI-based measurement. It's very favorable in terms of the overlap of the patella to the trochlea. We think that's the relationship that matters, right, the patella versus the femur. But the problem is if you have a laterally tracking patella and you're getting the central slice on the MRI, you're not going to get the overlap as a pure variable. So let's talk for a moment about overload. Chondral injury is an obvious one. If you have lateral patellofemoral cartilage injury, especially if you're going to try to do some sort of reconstruction procedure. If you have joint space narrowing on your X-ray, and then if you have pain in the absence of any other findings, some people use CT with spectroscopy to better delineate this and sort of show the overload. So once you've determined that you want to do a TTO, how do you do it? There's some systems out there with some planning and some sort of kits to guide your cuts, but really I prefer to do this freehand. You can just use two pins as a guide or whatever your preference is to just come across that tubercle. If you keep it flat, that's an Elmslie-Trelod, it's the medialization. You keep the periosteal connection distally so that you minimize the risk of nonunion, give it a little added stability, and then rotate it on a hinge. This is for pure instability work. And then if you need to unload the joint as well, you can treat both things by making that cut oblique as Dr. Fulkerson taught us. So you can see that cut there. And then you can customize that if you want to make it more anteriorized for each amount of medialization, you can make that a very steep cut and that allows you some flexibility there. Again, keeping that periosteal hinge distally. And then we've known for a while that that is best for your lateral lesions, your distal lesions, for lateral patellofemoral overload. Those patients did best in Dr. Fulkerson's early study and in the lab that sort of bore out that we unload the lateral side, but we do load those medial chondrocytes you want to think about where your cartilage injury is. So if you want to distalize, there are two ways to do it. You could either just finish off your anterior medialization Fulkerson osteotomy and take away that distal bone. Or if you want to stay out of cortical bone, you can stay pretty deep as shown in this x-ray and make a step cut. There are sort of pros and cons to both, but both are very viable. In either case, though, you worry a little bit more about nonunion because you violated that periosteal hinge. We worry about that dense cortical bone healing. Keep in mind here, I've created a dreaded black line, right? So if you have athletes trying to get back to run, that's the last thing to heal. That's what keeps me up at night. So you want to make sure that heals well. And so in the lab, these were shown to increase pressures in early flexion. But the problem with these studies is that these cadavers don't have patella alta. And so there are those of us who do a lot of these who really believe that patella alta is an edge loading phenomenon. If you distalize that very carefully, very accurately, then you're going to spread out those joint forces. And so we hope that this does not bear out in someone who's anatomically abnormal. But stay tuned for more on that. So in summary, you want to add your TTO for malalignment. You want to add it for overload. And in general, as you're thinking about who should get what, in the high level athlete, we trust their mechanics. We trust their soft tissues. You're going to see us doing more soft tissue only procedures. But in my population up in the Pacific Northwest, we have a lot of Ehlers-Danlos for one reason or another. And so I find myself not trusting those soft tissues, not trusting that alignment, having a lower threshold to move the bone. So that patient on the bottom there, you can see the cartilage wear on the lateral side. She's a dislocator. She has Ehlers-Danlos. Her TTD is only 11. And so you can see this dogma doesn't quite exist where we want it. And I'm definitely moving that tubercle. Thank you so much. I'll turn it over to Dave. Good morning. Thank you to Anna and the committee for the invitation. I'm Dave Dedock of the University of Virginia. And my talk is Congruity and Containment, which I think is also a very good title and prompted me to think about this in some new ways in terms of teaching and the role of trochleoplasty. My disclosures. So a recent meta-analysis that was published looking at 17 studies showed that trochlear dysplasia was the most important anatomic risk factor for recurrent instability. That doesn't tell us when we need to change it. It just tells us it's important. I think much more important from this study was how when you combine anatomic risk factors, your risk of recurrent dislocation goes way up. With three anatomic risk factors, you're approaching 80%. So you really ought to stop and think about changing the anatomy, not just putting an MPFL graft in there. So first we need to recognize trochlear dysplasia. And I do this on the lateral x-ray to know when I need three-dimensional imaging, such as an MRI or in some cases a CT. The blue dashed line is the base of the trochlear groove coming out of Blumensat's line in the notch. When that crosses the red dashed line, which is a lateral trochlear ridge, they're at the same level. It's flat. That's called a crossing sign. If you continue further anteriorly as you move proximally, that is a supratrochlear spur that sits in front of the femoral shaft. Then I know I need three-dimensional imaging. This slide is very important. This is the same knee. On the left, a merchant view 45 degrees of flexion has got a great trochlear groove anatomy. That's containment. The trochlea contains the patella as you go into flexion, not an extension. There's no containment in full extension. However, this knee in full extension has a convex trochlea and no congruity whatsoever. So trochleoplasty can improve congruity, but it's not going to improve containment because the convex shape like this is going to result in dramatic instability. Now flat is not a problem. Flat on flat can be balanced, especially if you have good patella-trochlear cartilage overlap as you see here with the patella-trochlear index is very favorable. But in this type of a situation with a convex shape and extension, which way is that patella going to go? It's going to be highly unstable. There's no way a soft tissue procedure alone solves this problem. That's doomed to fail. DeJure has given us a classification system which really just describes shapes. It doesn't guide treatment. The Bs and the Ds have the supratrochlear spur that sits anterior to the femoral shaft and an opportunity then to drop it down and correct it to flush with the femoral shaft, and really the type Ds are the target patients with this cliff sign and a dramatic spur that coexists. But the next one, I really quantify that spur, not just merely the presence of it or the shape. And a lot of papers that look at trochlear dysplasia just group them into categories by shape, but that doesn't guide treatment decisions. So I'm gonna drop a line down the anterior femoral cortex on the sagittal cut at the notch. That should be the deepest part of the trochlear groove. All of the bone plus cartilage that sits anterior to that is essentially abnormal, and that's gonna be the size of the supratrochlear spur. And seven millimeters of size of spur anterior to the femoral shaft plus a convex shape is my threshold to start to think about a trochleoplasty. Now next, does that spur actually influence the patella? The key exam finding is a J sign on active knee extension. Now this patient's under general anesthesia, but you can see the abnormal tracking as the knee goes into extension. This is a super patella view through the scope, and that's what's happening with the J sign. And here in this same patient, intraoperatively, you see this huge spur sitting anterior to the femoral shaft. The concept of doing a mini trochleoplasty to just remove the bump doesn't really seem to apply when you have situations like this, where all of that sits in front of the femoral shaft. I don't know how you just remove a bump without encroaching on a major part of your articular cartilage. So when you see the J sign, understand what's going on. That patella's completely leaving the strength of the groove in full extension. So that is either patella alta, which is significant, or dysplasia, or quite often both. And the interplay is very important, because the higher that patella starts, it has to come across all of the dysplastic trochlea every time the knee flexes. There's also a lateral vector acting on the patella of some sort, and I really think about patella instability in terms of vectors, and try to make it as simple as possible when I'm conceptualizing this. Here's a good example. The bottom right picture shows an extreme PTLTR, patella tendon lateral trochlear ridge. That tendon is draped way over the side of the lateral trochlear ridge. There's no way you can just pull the patella over and centralize that and get that to work. This person also has severe patella alta. Patella alta will often give you a very high PTLTR, even when the TTTG is not very high. So it all goes together. But in this case, because the patient started so high, I could move them down and move them over and engage the trochlea in a more normal groove, and a trochleoplasty is not necessary. So the times it's really gonna be something to consider is when you have that convex surface. So my decision making is I'm always doing an MPFL reconstruction with these patients because a trochleoplasty does not give me containment, and I'm thinking about this with type Bs or Ds with a convex surface and a bigger spur, and especially if it's in the setting of alta or a revision procedure. So here's a brief video. Intraoperatively, that spur's about 12 millimeters, and I'm gonna mark the distal extent of where I'm gonna make the cavity. The native trochlea groove is typically going in a medial direction. It's dysplastic and medial, which makes it even harder for the patella to get that far over. My new groove is gonna go straight up the femoral shaft, which is the solid line, and the inflection points on either side is where the distal extent will be. That blue line was a line extrapolated from the anterofemoral cortex all the way down to where it intersects the cartilage. That's the distal extent. I'll start with an osteotome to remove a wedge of bone around the edge. I'm gonna mince that up and save it for later. It's gonna become helpful. So I'll start the cavity with the osteotome and the ranger, then I come in with a high-speed burr, three millimeter egg burr, and I'm just gonna begin this creation of a cavity behind the cartilage and the bone. I'm striving for a five millimeter thick osteochondral shell so my offset guide, this is commercially available, is five millimeters in depth. I only use the five millimeter size because I'm looking for a shell that I'm gonna osteotomize. It doesn't work side to side. We all wanna use it that way as a surgeon, but you really have to windshield wiper it like this for it to be efficient because it's on a drill rather than a burr, so it's at a lower speed, but it does add a measure of safety and reproducibility for me to do this procedure. Then next I'm gonna use a 20 blade and a bone tamp to crack the osteochondral shell up the middle where I want it to crease, and then on the far lateral side, don't let those cuts connect, and the medial side's always malleable enough that you can just bend it down, and then I'm gonna fix these shingles in place with number two varicose sutures. I use two of them, and absorbable anchors, typically a tap-in anchor. You could use a screw-in anchor, but you definitely need to tap that if you do, and two sets of sutures, bring it over the top, and you can kind of selectively place your proximal anchors so that you can optimally bend the shingles in the shape you want, and this is really dropped down to flush with the anterior femoral cortex. Packing the bone around the edges will give you a little bit of lift, but you're not gonna really get containment with this operation. So we're dropping it down flush with the anterior femoral cortex, removing that convex spur. It's now flat on top, moving into a more congruous surface as you move distally, and the before and after looks like this, and the cartilage tolerates the sutures very well. Now, what a trichotofascial can't fix is this lateral vector. So if you see the patella sitting over the side, you have this kind of a vector pulling it sideways, you've gotta do some kind of an osteotomy to change that vector, and you need to be thinking about rotation, alignment, genu-valgum, et cetera, and here's a patient a couple years out, two and a half years out, beautiful correction, love the cartilage on my MRI, but look, the PTLTR is still sitting over the side. That vector's no good, and so eventually, this happens in extension. They're gonna go back to this, even though they're not dislocating, they're gonna still have this problem. So to kind of make it simple, if you've got patella alta and dysplasia, you need to be thinking about doing something more than just an MPFL. If you've got a jumping J sign, you need to be thinking about doing something more than an MPFL. You typically have alta and dysplasia and an extreme lateral vector. A flat, prominent sperm may benefit from a trochleoplasty. That's a little bit theoretical, but a convex trochlea is that one, and it's a very small subset that needs this trochleoplasty. Thank you. Outstanding lectures and updates on everything, and so we're actually on time, so we'd like to invite people from the audience to ask any questions of the panels. For the distalizing tibial tubercle osteotomies, any particular pearls as far as technique, as far as bone grafting, or putting something over top of that distal osteotomy site to prevent non-unions? That's something that I'm seeing a decent amount of, or where someone even has a post-operative tibial fracture, things like that. Any things you guys are doing in the operating room to try and help prevent that? The one thing that I've started doing is trying to peel back the periosteum, and then hold it, bring the tibial tubercle down, and then re-sew the periosteum. Most of the time, these are sort of late teenagers. They have pretty thick, and I think it helps me. Three screws. If I'm moving more than a centimeter, which is a big distalization, I'll take the block of bone and move it proximal to fill the gap, but if less than that, I'll do an overlap, and that seems to work, but three screws and bone grafting the cavity on the lateral side after it's moved over. And the last thing I'll add is, if you do stay inside of cortical bone, and you don't see bleeding, if you finish off your Fulkerson, and you don't see a lot of bleeding, it's easy to take a K-wire and just fenestrate that bone, and generate some aperture for that healing to happen. Thanks guys, great talks. Alex from New York. Regarding the trochleoplasty, can you speak as to why you use a thick flap versus thin flap technique? So there's two methods described. Phillip Schottel has popularized the thin flap, and that narrows it down to a three millimeter osteochondral shell that's inflexible, peeled up, lifted up like the hood of a car, and then you reshape the bone beneath it, put it back down, and hold it with vicral sutures. Honestly, I have no experience with that, so I wouldn't be so bold as to say one's better than the other. My concern is making it too thin, and then I worry about cartilage perforation, I worry about heat necrosis. I know he's gotten great results, I know a lot of people have gotten great results. The principles are the same, I think it's what you're comfortable with. I just would like to add one thing. I was brought up on the thick shell, but I think that you do have some flexible cartilage, and I used to think it was more in kids, and then sometimes you just have such incredibly thick bone underneath that lateral condyle, so for me, or that lateral trochlea. So I think that sometimes you can get away with a thin flap without making the osteotomy, even with five millimeters of bone. I just think you have to be prepared to do both, or have it both in your toolbox. Excellent, so we'll move forward to the case discussions, which I'm sure we'll elaborate on more questions, and Dr. Ferrer will take us through that charge. Cool, thanks a lot. I'd like to thank Anna for always pushing innovation within orthopedic sports medicine, and once again, pushing innovation with the very great lineup, as well as idea for combining with Ruth Jackson Orthopedic Society. Thanks, Brian and Mary, for allowing me to be here. So these are our panelists. So these are my disclosures. It can be found on the website. So first case, 11-year-old, subluxation since she was seven. Three recent frank dislocations. She's premenarchal. Parents are very tall. She's got a lot of growth yet remaining. Has a very mild J sign. Her CDI is 1.2. Crossover sign, and then she has a TTTG at around 15 millimeters, and what I call mildish dysplasia. Takes a lot for me to get scared with bumps and whatnot, and so I didn't think this was very significant. So 11-year-old athlete, anyone need any additional information? Jacqueline, or you got enough to make a decision here? I think it's never a bad idea to get standing alignment views, to get bone age information, either from your MRI or from a hand X-ray, but I think we have the information here that there's a lot of growth left. Excellent. Certainly, slight valgus alignment, but nothing that I was too concerned about from a rotational standpoint or a coronal plane alignment standpoint. Liza, you got this athlete in your office with her parents. What are you thinking, plan-wise? We all worry about a J sign, and we all feel that when you have a jumping J sign, however we want to signify it, it probably needs something bony, so when you see somebody with open growth plates, that's difficult, but the mild J sign, to me, is something that relocates very early inflection. You don't have any crepitus, which means that the cartilage is still probably fine, and the most important thing to me is is it present on the other side where they may not be reporting instability, so I also would try a McConnell tape technique in these athletes to see if I can get by with just a medial stabilizing procedure, which would be the preferred thing with someone with open growth plates, so for me, what does the contralateral side look like if they're not bilaterally unstable, and does it respond positively to a McConnell lateral to medial tape technique? Cool, and then, Mihael, any, in your clinic, in this patient, is there any role for non-operative treatment at this point? Multiple dislocators, she's 11. Volleyball athlete, can you just hold it down? Sorry, well, she's been having recurrent dislocation since the age of eight. I think it's a little tough to make that argument. I mean, certainly, I always do go through making sure that they actually have had some sort of conservative management and that it's real conservative management. Do they actually go to physical therapy? Do they actually work on core, hip, quad, things like that? But I think in this case, it sounds pretty much like she's failed those options, so I would say no. And Dave touched on that article from Huntington. You look at this as a young patient, she's got only immature, she's got some dysplasia, no ulcer, but she's at a high risk of a continued dislocation, and she has a prior history, so that we talk about with the parents. So this is, we did a NPFL on her. Technique-wise, in the skeletally immature person, wide open growth plates. David, what's your decision for fixation in this patient? More or less the same as an adult. I'm still gonna use a femoral tunnel, I'm still gonna attach it to the patella, be it suture anchors or tunnels, I think it's dealer's choice. But the point of attachment's gonna be just distal deficits, so I'm gonna really use the flora and the OR and get it right, maybe use a smaller tunnel on the femur. But I think one of the important takeaways from this case is to treat this patient. I mean, they're 11, not to say, well, we'll just try to get you through till you finish growth. I mean, it's been dislocating for years, it's just a matter of time before they have a catastrophic chondral lesion. And to treat this patient is probably the most important take-home for this. Cool, and it is our technique. I use bone tunnels also, so on the lateral, if you use Shadow's point, it should look like the tunnel is on the growth plate, and that's because of the anatomy of the growth plate. We know that the NPFL attachment is a few millimeters, about six millimeters distal to the growth plate, but on the lateral, you're seeing the undulating portion of the physis, but on the lateral, it should be well beneath the physis and aimed distal and anterior to kind of stay out of the growth plate. That was our plan for her NPFL reconstruction. She has some tilt, so we did do a lot of retinacular lengthening. So, hypothetically speaking, David, if she has a large spur, she's convex at 11 years old, what are your options at that point? For the dysplasia, nothing. So you just kind of treat it? Not my hand, yep, I think just treat this, and I think to not treat it and wait for them to finish growth is probably a mistake, and I've certainly seen that. I've seen some people with really weird anatomy, and literally in the time waiting until surgery, I saw one person get a catastrophic chondral lesion. So I think the better answer, even though you know it may not be the final thing they need, is to do something to improve their situation, their instability, when they're this unstable, they start dislocating at age seven, the writing's on the wall. So convex trochlea in this person, that's one of your contraindications to trochleoplasty? Because they're skeletally immature, with this much growth left. As they approach maturity, it's kind of like an ACL patient within that last year or so of growth, then I can go ahead, but not this young. Okay, and then to that same question, Jacqueline, if she's ALTA and she's malaligned, TTTG's high, what are your options in that patient? Because I assume you're not going through the growth plate. Correct. Jack Andrush, I believe, has described a way to shorten the patellar tendon that I don't have a lot of personal experience with, and that's on the table. It really depends on how high it is, though, because Pete Fabrikamp showed us that even soft tissue reconstruction alone can improve some of your numbers. So, if it's, I think in my practice, in an 11-year-old, I would hold, I would do soft tissue reconstruction alone. I would hang a little bit of crepe on whether she's gonna have preserved apprehension sign post-operatively and whether we think that's gonna evade us in the post-operative setting and maybe stage it for when she's skeletally more mature. But, I mean, there are a couple of papers that say that soft tissue reconstruction alone should be effective even in patellar ALTA. Yeah, and I will use patellar tendon shortening in this population if needed. So, excellent. So, this is her. She's done great with this. She actually, she's five years post, and she actually, as a high school volleyball player, dislocated her other patellar recently. We're treating that one non-op. That's a first-time dislocation for her, and that's what they chose to do. So, again, we sort of talk about what we're doing in terms of treatment. So, mild J sign, kind of NPFL plus maybe, and then she's a de jure, in my opinion, and the CDI was 1.2. So, she's a little high, but it certainly has been pointed out. You look at all the parameters, and she has a lot of, enough chondro overlap where we did not think we need to do anything with her mild to moderate ALTA. Liza, certainly, this is a hard question, I guess, but of all the factors when you see these patients, what is the one factor that scares you more than anything else? They said, I have to add more than just soft tissue reconstructions, if you can answer that. I think a J sign, but if the problem is we can't really, we don't know how to describe it. Right now, it's more qualitatively, although Miho and Andy are trying to work hard on that. But I think that Dave was saying a catastrophic injury, but I know that you've seen recurrent J signs create bipolar lesions on the superior lateral trochlea and on the medial side of the patella. Medial side of patella cartilage lesions are very hard to treat, as the cartilage guys will tell us as well. So for me, it's a J sign. I also think patella ALTA is more difficult to use. You can have the dysplastic trochlea and maybe get by with what some people are calling a staging MPFL, when the open growth plates are there. So I do think that if it's really high and you have no trochlear engagement, I would go the Jack Anderson, the Cleveland Clinic route, like you do, Lutel, and think about patella tendon shortening. I think it works better in women than men, if you wanna know the truth, because I think men have really rapid growth spurts where they might grow seven to 12 inches in a year. And I think that I see the patella tendon sometimes stretch out more in guys that are premenarchal or what we would call premenarchal in the boys that still have a lot of growth left. For me, it's a J sign. Yeah, that's 1000% accurate. I like, I've noticed that too. Miho, you agree with that? Sorry, sorry, sorry. Yeah, I agree with that. I would say the other thing that makes me kind of think a little bit harder is when the patella is lateralized and kind of stuck over there. Even, that's kind of like one of my few indications to actually touch the lateral side. But I also think that it is a sign that there's more going on in terms of alignment that might not be as apparent. And so whenever I see that, I kind of look a little harder for other things. Cool, thank you. So you beat that horse. All right, so next case, this is a case that Liza sent to me, so appreciate that. Primary lateral patella dislocation, 15-year-old gymnast. She had a non-contact injury, doing a tumbling routine, and she's one year status post the first start of her menses, so she's probably hit her maximum growth velocity. So thin, normal alignment, normal gait, kind of mild kissing kneecap, so she's a little, some femoral anteversion. There's her hip range of motion there. She's got positive apprehension, no J sign. A fair amount of lateral translation. Elevated Biden score, includes knee hyperextension. And then this is her alignment series, so some valgus, bilaterally, but more on the right side. And that was her merchant views, or her coronal views towards full extension, or towards extension. So her CVI is 1.28, insolid cell body is 1.35. She's got closing FIC so she looks pretty close to skeletal maturity, and then a low-grade trochlear dysplasia. So this is her patella tilt at 22 degrees. Her TTTG is not elevated, 14 millimeters, and she's got some mild chondro-wear, consistent with her instability, so a kind of inferior median ridge of the patella. And then this first slice of her MRI, we sort of see some dysplasia of the trochlea, as well as some lateral displacement of her patellar tendon, or quadriceps tendon, or patellar tendon, sorry. And she's got some ulta, but her patellar trochlear index is 0.23 on her sagittal MRI. So these were the things that Liza was sort of thinking about, so isolated NPFL, and so ulta's kind of borderline here, high-level gymnastics for many years, and then the idea of distalizing her TTO and the concern with a return to play with adding the TTO in. Jacqueline, Jackie, what do you think about TTO and your athletic population, our young athletic population? I have certainly undertaken TTO in athletes in the past. I think that hyperextension at the knee can certainly create a pseudo patella ulta that's hard to catch on your lateral X-ray with your conventional measures. So if the patient is very lax, which it sounds like she's flirting with that, and she's got knee hyperextension, the only issue that I have with the patellar trochlear index here is you can see that that's a laterally tracking patella, and so I don't think that's a true number, and I'm not that impressed with the Catan de Champs. So I think I would hesitate, and I'd get a good exam and see what ... Did you mention J-sign? No J-sign. No J-sign. Okay. I think I would hold. I think I would go NPFL alone and an athlete with that data. And Liza, if you are distalizing, how much distalization do you get afraid that you may have to do something to the quad tendon? So what's your cutoff for amount of distalization? I can tell you exactly. I got accepted in my paper with 69 patients. The largest I do is 15 millimeters, and that's a lot, and that doesn't always correct it for very high ALTA, but the majority of them are between 10 and 12. Okay. Thank you. All right, so, and this, again, sort of look at all your parameters, and we hang our hat on a lot of these numbers, but certainly they're not dogma, and you look at sort of this, which is an incredible amount of hyperextension in this patient, so all those numbers for like ALTA and stuff just kind of go out the window because this patient is fully, fully out of the containment of her trochlea. So does this degree of hyperextension change your algorithm? David. Well, just thinking about the kinematics of the NPFL graft, that's gonna be, I mean, you just think about where it has to move, that's gonna be hard, I mean, just to maintain the integrity of your graft. So I think this goes back to that meta-analysis that the combined anatomic risk factors really elevate your risk of recurrence. So this is, you know, maybe all those numbers together are just borderline, but she's got them all, plus she's hyperlaxed, plus she hyperextends. I mean, I just, that tells me I gotta think about a bony procedure. I'm gonna increase the chance of success with a bony procedure, bring this patella down. If you go back two slides, if that's possible, this was an example of somebody who, this isn't the PTLTR quite, but you're starting to see that tendon wants to go lateral, and it's because the combination of valve, a little bit of valgus, and a high-riding patella. So it'll tend to create a bad vector to pull it laterally. So all these things start to add up, and I think you're gonna solve a lot of them by moving it distal. Yeah, so we're, I would just wrap this up here real quick. So she did well initially, left side, then dislocated, but then she re-dislocated her right side, and underwent, reconstruct, sorry, so re-dislocated the left side, sorry. Right side was doing well, she's a senior in high school, talked to her about conservative management for that, and they decided on conservative management, but I thought that was a pretty good illustrative case about certainly things that certainly may change your thinking with respect to our parameters. Yeah, I'll just say that this is the person that made me think about hyperextension. As you can see, the re-dislocation was 215, so this was 214, and I do tend to lower my threshold for surgical management with hyperextension. And you're right, David, but what we'd like to do is keep them out of hyperextension. So maybe in day-to-day activities you can, but when they fall or they come down from a jump, that's hard. So PT has to try to emphasize awareness of hyperextension and avoid when possible. So we changed a lot of her gymnastics routine when we came back after the first one. Yeah, thank you very much, everyone.

risk factors

patellofemoral instability

surgical correction

recurrence rate

MPFL

individualized treatment

axial plane alignment

surgical outcomes