Thank you. First of all, I'd like to thank Meredith Herzog for getting us set up here tonight and all the great things that she does here for AOSSM. I'd like to thank and welcome everyone who's tuned in for this webinar series today. This is our Patella Femoral Talk, and we are going to present. I'm the moderator, and we welcome Jacqueline Brady, David Dedeck, Beth Schubenstein, and Miho Tanaka for what looks to be a great lineup here to discuss patella-formal instability, something that's near and dear to all of our hearts. This is truly a star-studded cast, and we're welcome to have them here with us tonight. And we will get started. So tonight, remember, questions are what kind of really make this thing go. So if you have interesting questions, there should be a box, the GoToWebinar box, somewhere on your screen, and you can enter questions here. We'll try to address each and every one of those questions, and certainly discussion is really what makes these things special. The talk will be outstanding, but certainly discussion is what is great. So please write down questions and send them to us, and we'll address those questions as they come in. And first up, we have Miho Tanaka, who's going to talk about our first time patella-formal dislocators. Thanks, Latul. Let's see. Okay. Well, thanks so much to Latul for bringing this together, to AOSSM, and obviously to the co-faculty. It's always fun to do this with friends. So I'm going to be talking about first-time patellar dislocations, when to operate, and how to decide. These are my disclosures. So when it comes to first-time patellar dislocation, we know that this constitutes two to three percent of all knee injuries, and the prevalence is 23.2 per 100,000 person-years. It's highest among adolescents ages 14 to 18, slightly more common in females. In the mean age, the first dislocation has been shown to be 21.4 years. Now, it's been shown that up to... Dr. Tanaka, we don't see your slides. Oh, no. Okay. Hold on. Let's see. There we go. Can you see them now? Yes. That's weird. Okay. Is this full screen for you guys? Yes. Okay. Not so. But now we can't see them. Now we can't see them. Okay. All right. So I don't think there's anything to show. I'm going to go back real quick. Title slide, disclosures. Okay, great. Sorry about that, guys. Thanks for letting me know. We still can't see them. We don't see it still, though. So if you went back to that other page, and we're in show screen. Okay. Yes. That we can see. So is this in PowerPoint mode, though, and not in slide mode? Yeah, this is in slide sorter mode, but we can see it. The slide that we see is who needs surgery. So do you want me to just stay on here, then? Because we had it earlier on presentation mode, but I guess we'll just kind of do that, I guess, because I'm afraid I'm going to try one last time. So if I do this, it goes off. Yes. Yeah, it's going off. Yeah. I think you got to stay in this mode and just make it small like you did. Okay. All right. Sorry about that. This is actually we just tested this and went okay. But okay. So just tell me if there's an issue. Going back, so we're talking about first time patellar dislocations. It's been shown that up to 16% of these can undergo acute surgery for an osteochondral injury, and that up to a third of these can undergo surgery for recurrent instability. So what we'll talk about today is how do we know when to operate? In terms of acute operative indications, I think this is pretty well established at this point. Any sort of symptomatic loose body greater than a centimeter or repairable osteochondral fracture should be addressed acutely. This also underscores the importance of obtaining an MRI, especially when these patients have an effusion or rheumatosis in order to not miss this early on. Now, once you've ruled that out, then if they're treated conservatively, what we know from Bob Magnuson's study and from many others is that a third of these end up being normal. Another third end up being stable, but symptomatic. And then a third of them continue to be, frankly, unstable. And I think the important part is trying to figure out which of these patients end up in this unstable category to try to get to them a little bit earlier. Balcarp published the Patellar Instability Severity Score in 2014, looking at 61 lateral patellar dislocations, and 40 of them were found to re-dislocate within two years. They looked at six specific risk factors, age less than 16, bilateral instability, the presence of turgular dysplasia, patella alta, as indicated by an end-cell cell body greater than 1.2, TTTG greater than 16 millimeters and patellar tilt. All of these were measured on MRI. They found in their study that sex and physical activity were not significant. And if you add up the scores as shown in the table here, and their score was greater than four, then the risk of early re-dislocation was five times higher than those with lower scores. Chantal Parikh's group followed up on this with a larger series, specifically in children. So this is age less than 18. And in 250 patients, they found that 60%, sorry, 16% needed acute surgery and 83% were treated non-operatively, of which over a third ended up recurring. Now the majority of these recurrences occurred within three years. And in their multivariate analysis, they found that turgular dysplasia, any du jour for this one, and skeletal immaturity were the greatest risk factors. And if you factor in the presence of bilateral symptoms and patella alta, as indicated by Ketan Deshant, index greater than 1.45. And if you had all four of these risk factors, then your predicted risk of recurrence was 88%. So that's pretty high. This was Liza Arendt's study. This was actually a prospective one, where the last two have been retrospective. This was in all ages looking at 145 knees. Now in this study, 42% recurred within two years. And they had three primary risk factors, skeletal immaturity, again with open feces, a sulcus angle greater than 154, so another measurement of turgular dysplasia, and then patella alta, as indicated by Ansel Salvati, greater than 1.3. And if you had all three of these predictors, the predicted probability of recurrence was 78.5%. The last one I'll talk about is a recent study out of Mayo looking at the long-term risk factors. So these are patients that were followed for over 10 years, and almost half of them ended up having recurrent instability during this time, and over a third of them underwent surgical stabilization. And they similarly came up with a point value system, where if you had a score of four or five, so basically all of these factors, then you had almost an 80% risk of redislocating during that time. With all of these studies, I think they have some similarities. So the factors to consider, you can think of them in terms of patient-based factors, so age, skeletal maturity, the presence of bilateral symptoms, and then radiographic factors. So these include turgular dysplasia, patella alta, and chronomal alignment. Now I will point out that there's a lot of variability in terms of what was measured, so what exactly was used to qualify these findings, the techniques of how they measured them and how they reported them, but these were the general themes that you can see in all of these predictive models. So does this mean that we should be operating more on these first-time dislocators? Well, let's see how they do. Comparing in terms of MPFL repair versus bracing for first-time patellar dislocation, Maria Askenberger's group looked at redislocation rates in this group and found that in the repair group, redislocations were actually lower than in the non-operative group, but still at 22%. And in terms of functional scores, these were fairly comparable with the Kujala score of 90.9 in the repair group versus 95 in the bracing group. They also found, in terms of anatomic risk factors, particularly with turgular dysplasia, that this increased the risk of redislocation. So in summary, this study showed that MPFL repair reduced the risk of redislocation, but it didn't actually improve subjective or objective knee function in these first-time dislocators. Now the question then becomes, is this because it was repair? And we know that in cases of recurrent instability, comparing repair and reconstruction, reconstruction has been favored in terms of outcomes and recurrence rates. And Pedowitz looked in his series of 41 adolescent patients who had an osteochondral fracture that needed acute surgery after patellar dislocation, some of which underwent a concurrent MPFL repair when they could actually see the MPFL tear. And comparing those that had an MPFL repair versus those who didn't at the same time, both were found to have degree dislocation rates of over 60%. In terms, the one thing I would point out though, is that in terms of the operative treatment, this happened on an average of 64 days after the initial injury and up to 450 days. So they weren't necessarily always acute immediately after the surgery. And they did also point out that there was a greater risk if the TTTG distance was greater than 15 millimeters. The only study that I know comparing non-operative treatment with MPFL reconstruction in first-time patellar dislocations is a study out of Brazil, looking at 44 patients, a prospective study, and they did find that the Kujali score was higher in the operative group at 88.9 versus 70, and that those who had surgery were seven and a half times greater likelihood of having good excellent scores. They did also find that the presence of a crossing sign, again, a sign of trochlear dysplasia yielded lower Kujali scores. And there was a 35% recurrence in the non-operative group, which is expected versus zero in the surgical group. So does this mean that we should be operating and doing MPFL reconstructions on everyone? Well, we know that this is not a procedure that has no complications. We saw in Shaw's study from 2012 that the complication rate is about 25%. So we really do have to be selective about who we're going to operate on. The flip side of this, though, is that in terms of cartilage changes, we know that this is also a concern with each patellar dislocation. This study out of Mayo looked at 609 patients with first-time lateral patellar dislocations and compared patients to those who didn't have dislocations and found that the cumulative incidence of patellar femoral osteoarthritis increased with every five years and that the main risk factors were recurrent dislocation, osteochondral injury, and the presence of trochlear dysplasia. And one of Beth's older studies from 2011 looked at the chronicity of patellar instability and found that the more chronic this was, the more likely you were to have cartilage changes, particularly on the trochlea. So I think these are all things that need to be weighed together. So in summary, with the management of first-time patellar dislocations, I think the first thing is to make sure you're not missing an osteochondral lesion that needs to be repaired or a loose body that needs to be addressed. And if you do have to address that, then I think repair or reconstruction at the same time should be done. Now, whether you do one or the other, the jury is still out on that. I would say that the majority of people are probably doing repairs, but the literature is starting to move towards reconstruction. But currently, there's no direct comparison between the two. So I think there'll be more to come on this. If there's no acute finding, then I think it's important to risk stratify. So looking at age and skeletal maturity, bilaterality, and then using that MRI that you get to look at morphological risk factors in terms of trochlear dysplasia, ALTA, and malalignment. And if they're high risk, talk to them potentially about surgery. And if they're low risk, start with conservative management. And if they re-dislocate, then consider surgery at that time. But I think the most important thing in all of this is to talk to the patient, educate them and their parents, and then go with a shared decision-making model. Thank you. Thanks, Miho. That was fantastic. And we're going to transition to our next talk. Steven Stein is going to talk about when NPFL reconstruction is not enough. Okay, guys. Okay, can you guys see my screen? Yes. All right. Sorry about that. I had to go back in. Well, first of all, thank you very much to Meredith and Dr. Ferro and everybody for inviting us and having us here tonight. And again, a topic near and dear to all of our hearts. So excited to do this, and then hopefully get some great questions to answer afterwards and hopefully get some consensus for everybody. So my topic is NPFL. And I always say, oh, the real question is, is NPFL reconstruction enough? And the answer is yes, except when it's not. And I have nothing to disclose. The issue with regard to NPFL is, is it a sufficient surgery for people who are either first-time dislocators in that high-risk group that Dr. Tanaka was just talking about, or if it's a patient who is in a very high-risk group, first-time dislocators in that high-risk group that Dr. Tanaka was just talking about, or if it's a patient who has had a recurrent dislocation, can you just get away with an NPFL? And sometimes with fairly normal anatomy that has some low-grade dysplasia, some low-grade coronal malalignment, some low-grade ALTA, you can definitely get away with it. And I think that's going to be that 30% where they'll do fine. And there's others that are at the other extreme end of the spectrum. They have extreme valgus, sometimes femoral anteversion, extreme ALTA, and extreme trochlear dysplasia. And obviously in that group, an NPFL is not going to be enough. And I always try to reiterate that an NPFL is not a pulling ligament. It's not meant to pull the kneecap back in place. One of the best quotes I've heard is, I think it's Adam Yankee's quote, where he says, you've got to line up the putt. You've got to get that patella back where it's supposed to be, and then use the NPFL to hold it there, but it shouldn't be used to pull it there. But what do we know? Well, what we know is that the NPFC or the NPFL provides 60% of the resistance to lateral translation of the patella. We also know that it is isometric through the early range of knee flexion, but that it then loosens in deep flexion as the bony congruity takes over. And we also know that we're getting better at this. Schneider's article, which was a systematic review, really showed that as we do more of this, as this operation has been around for a longer period of time, we're getting lower and lower dislocation rates, lower complication rates, and higher return to sport rates. And so we're overall doing pretty well when we do an NPFL. As Dr. Tanaka just talked about, we have better evidence now in terms of prediction models for who is this high-risk dislocator and who do we need to worry about. Although we haven't really decided whether we should operate on them after their first time, I think we're getting closer to nailing this down. And I think as Dr. Tanaka said, there's more to come on this, and we will figure out how to risk stratify this group rather than treating all comers the same as we currently do now. Where there are gaps in our literature right now is that there's no clinical studies that tell us what degree of ALTA, TTTG, or trochlear dysplasia predict failure of an isolated NPFL reconstruction in a patient who has recurrent instability. So we know that the first-time dislocator who does not have indications is treated non-operatively. That's the current standard of care. Obviously, we just heard about hopefully being able to risk stratify those. And we know that the current standard of care for a recurrent dislocator, anyone who has a second event, is surgical treatment. But what we don't know in that recurrent group is a soft tissue operation enough. When should we be adding a bony procedure? What predicts failure? So we look to the shoulder instability literature because they're about probably 10 or 15 years ahead of us. And Pasquale Below did a very good study. The ISIS score came out of his study in 2007. He prospectively enrolled 131 patients who had isolated soft tissue Bankart repairs who were dislocators. He followed them up and over the period of approximately four years, sorry 31 months mean, they had 19 re-dislocations. And then what they did is they did a logistic regression analysis on those patients who re-dislocated to come up with the ISIS scale, which is the instability severity index score, to predict who was going to likely fail an isolated Bankart and who would be better served by doing a Laterge ahead of time as their primary operation. We need that in the world of patellar instability. We need to predict which patients have an unacceptably high risk of recurrent instability with an isolated MPFL. And that way we can go right to the other surgeries, a TTO, a DFO, in some cases, although we can debate this, a trochleoplasty. So I started doing a study that was modeled after Below's study in 2014. This is a study that Brandon Erickson published the early findings, the early findings in 2017 in AJSM, looking at isolated MPFLs, regardless of tibial tubercle trochlear group distance and patellar height. And this was our early outcome. This study was really designed to be a multivariable regression, logistic regression analysis to hopefully look at these patients who fail and create this index score that we can use to identify the patients who would also benefit from a concomitant bony procedure. We have exclusion criteria for this study, included four things because of clinical equiposte, significant lateral unloadable chondral defects, got a TTO, not for the instability, but to unload that cartilage, which I was restoring at the same time. Anyone who had failed previous surgery for instability did not get enrolled in this study. And anybody who had pain greater than 50% is their chief complaint because an MPFL does not treat pain, whereas a TTO can unload and treat pain. And then a jumping J sign or a subluxation and extension. So those were the exclusion criteria. We followed them up. Brandon reported on the first two years. This is an example of a jumping J sign. I think most of us who do a lot of this would agree that that's not something you're going to be able to control with just an MPFL, that the forces on that ligament will just be too high. So, and then of course for pain. So we had 90 patients when this study was published. This study was looked at from March of 2014 through August 2017. As of a couple of weeks ago, we now have 175 who've had surgery. So we're going to start, actually Liz Dennis, who's our current fellow, is going to write up the midterm results now. And 152 of those patients have now reached a minimum of one year. At that point, we had 88% follow-up and various kind of typical gender distribution. They had a higher than normal TTTG as would be expected. It's an average and an average CDI of 1.2 as well. So patella alta. One patient at that point, this is now three years ago, it had a dislocation at three and a half years post-op and one patient had sublux, but overall 96% at one year were stable and 99% at two years. And the overall return to sport was high and on par with others. Unfortunately, the study got misinterpreted over the first year or two after publication. And it was not meant in any way to imply that we should be doing isolated MPFLs in everyone. It was really meant to establish a patella isis, which hopefully we'll be able to do over the next few years as we close the study and then follow these patients longitudinally. But the current guidelines right now that we have in general, most people use alta as either 1.3 or 1.4, TTTG as 20, although I've heard some people talk about over 15 if it's on an MRI and trochlea dysplasia. But it's really likely none of these in isolation, as we all know, because this is a multifactorial problem and it's rather going to be a combination that leads to failure. So hopefully we will start to see that over the next few years as we start to publish on this and get better guidelines to help us decide when to add the other surgeries. When we're doing an MPFL, always the question is, well, how do you get it right? I think Dr. Dedeck has helped us a lot with this in terms of figuring out where to put this on the femur. Obviously, Philip Schottel has helped us to figure out that zone that we want to be in. The MPFL is isometric in its early range of flexion. It then loosens after about 50 or 60 degrees of flexion, depending on the height of the patella, of course, and then bony congruity takes over. So it's really only responsible for the check brain in that early transition before it gets captured into the trochlea. For patients who have a fatal combination of trochlea dysplasia and patella alta, obviously the MPFL has a lot more stress for a lot longer into flexion. But either way, the femur is the key. Hopefully, I think Dr. Dedeck is talking about a different topic tonight, but I always remember what he says, which is high and tight and low and loose. That's how you can figure out when you're checking the isometry if you're in the right spot. And when I'm looking to find the right spot, I really go based on anatomy first. I find the sulcus. Then I do check the isometry, remembering those key words. If it's getting tighter inflection, I know that it's too proximal and I have to move it down and the opposite is true as well. And then finally, at the end, I use image just to make sure I'm in the right zone. And even Philip Schottel will say, it's not a point, it's an area. So you have to be respectful of that. I'm going to zoom through this a little bit. There's the anatomy part. I palpate the anatomy. Then I use a guide pin to put it where I think it should be based on anatomy. This is the isometry checking in extension. You want it to be isometric and then starting to flex the knee. And as you start to flex the knee after about 50 or 60, you should see that distance between the pin and the patella get shorter, which means the left tail should get longer. And you see that here. And I do want to see it loosen and deflection because that's what an anatomic or an MPFL should behave like. So how do we avoid complications? Certainly the major risk on the patella side is fracture. I used to do a docking technique, a short blind tunnel. I liked it. It didn't have any fixation in it, no screws or anchors. It was strong fixation, but obviously I got concerned about the risk of fracture. And so I changed it when I started doing these studies. I started to do really an isolated anchors on the medial side, really kind of go right back down to that medial border of the patella. I make a very small arthrotomy just so that I can palpate the surface of the patella because that'll allow me to feel where I want my anchors. And again, you want to aim for that kind of juncture of the proximal third and the distal two thirds. Then I can put my anchors in and again, right against that articular border. I think the major error that I see here is that people want to air away from the cartilage. And the more anterior you are, the higher the risk of fracture. I lasso the tendon. So I use a free hamstring graft. I lasso it against that. So it's a broad healing base for the patella. A little bit. So no sewing the tendon, just really lassoing it very easy. And it's a really strong fixation on that side. Of course, no matter where you do this, and a colleague shared this with me and let me show this, where you put the anchor, if you're too anterior, you do have a risk of fracture, even with a small 2.4 anchor. So you got to be careful. MPFL has complications. As Dr. Tanaka mentioned, malpositioning of the tunnel can cause a fracture. So you want to mention malpositioning of the tunnel can cause loss of motion, increased loads and pain and potential OA. And it also leads to increased anisometry, which will eventually lead to stretching, graft failure and redislocation. So looking at where you want to put this, always try to get it into that right area. Avoid tunnels on the patella. Use anatomic landmarks. Make sure you check your isometry and the OR and make sure it looks good in terms of where you think it, what it should look like. It shouldn't get tighter inflection ever. And then you want to set the length of your graft with your knee inflection. And Dr. Dedeck's group showed us that less flexion is better. So minimal flexion that allows you to engage the patella into the tropia so that you don't over-tighten it or over-tension it. Again, it's an anatomic operation. It is the operation of choice for a current instability. We are seeing decreasing complications, but we do need better studies to determine who needs a bony realignment or some other bony augmentation in addition to an NPSL. Thank you. Thank you, Beth. That was a great talk. Next up, we have David Dedeck, who's going to give a talk on trochlear dysplasia. Take it away, Dave. Thank you. That was a great lead-in. Can you guys see my screen yet? Yeah. You're good. Still see it? Yep. Awesome. So that was a great... I hear my disclosures, but the review of the literature was outstanding. Here's a systematic review that just came out in AJSM that looks at 17 studies and the recurrent dislocation risk and the odds ratio. Trochlear dysplasia tends to bubble up the top of all of these studies. It's clearly important. But interestingly, as Beth just alluded to, when you start to combine these anatomic risk factors, then the recurrence risk really elevates. And I think that's going to be where our understanding really improves in the future, is how these combinations play a role. And I'm going to get into that a bit with this talk about trochlear dysplasia. So there we go. So trochlear dysplasia can be confusing, but we're going to look at a stepwise approach to this. First of all, you've got to diagnose it. And the key is the lateral x-ray. It is not the sunrise view. So you're going to look for a crossing sign. That is going to be this yellow arrow. The blue hash line is the base of the trochlear groove, which is going to be where Blumesatch line exits the notch and then comes anteriorly. When that reaches the same height as the condyles, which is the red dash line, that is a crossing sign. That is at the same height. If it continues further anterior to the cortex, the anterior femoral cortex, then that is a supratrochlear spur. That are the green dots or the blue arrow there. And that is prominent and is going to be convex. So once I see that, I know I need some three-dimensional imaging. This is the same knee. On the left is 45 degrees of flexion, the standard sunrise view, unremarkable trochlear. On the right, full extension, you see that convex supratrochlear spur, and you also see chondrosis. So that's important to understand. It's not about flatness on the sunrise view. You're going to need three-dimensional imaging, such as a CT or an MRI. And if this is what you have, it's like an egg on a table. Which way is it going to go? And it can be profoundly unstable. So next we're going to need to quantify it. It's just not about, is it dysplasia or is it not? But I think what we really need to do is start to quantify this. I'm sorry, it's advancing on its own, but I'm going to use a CT or an MRI, and I'm going to drop a line down the anterior femoral cortex and measure how much bone plus cartilage sits anterior to that, and measure it on the sagittal cut at the notch. There you see the cruciate ligaments, and that should be the lowest point of the trochlear groove, and it should be flush with the anterior femoral cortex. All of this is a bumper supratrochlear spur. And de jure classification really doesn't tell us whether to do surgery. It just puts them into groups, and it's also not prognostic. It's also not quantitative. But the Bs and the Ds have these supratrochlear spurs, and the Ds have the really severe anatomy. So next I'm going to say, well, does this spur actually influence the patella tracking? Here's a jumping J sign on the right, which is profound instability, really symptomatic. And on the left, it's a superior lateral arthroscopic view, looking from above, and this is a jumping J sign with the patient under anesthesia. I externally rotate her foot slightly, look at all the chondrosis, and you see how it tracks laterally on this convex bump that sits anterior to the femur, and then jumps over, and that happens every time this person extends their knee. Very disabling. So what does a J sign mean? The patella completely leaves the restraint of a groove in full extension, and this is either going to be patella alta or dysplasia with a convex spur, or it's both. And that combination, I've found, is especially important because any spur has more influence the higher the patella starts, because it has to navigate over this every time. So I'm going to assess my patella alta. I'm going to use a CD ratio, which you see on the left, and I'm also going to look at a patella trochlear index, which you see on the right, because you can have a short trochlea and have the same effect as a high-riding patella. The patella still has to get into much deeper flexion before it finds any groove. And then I'm going to ask, well, maybe they have dysplasia, but could perhaps I work around the dysplasia? The mere presence of dysplasia doesn't mean you have to do a deepening trochleoplasty, and you could you could distillize the patella with tubercle osteotomy, and then you decrease the spur influence. That you see here, this patient had a moderate spur, but really very high-riding patella with a CD ratio of 1.5, no patella trochlear overlap, a patella trochlear index of 0%, and was very malaligned, excuse me. And so I moved the tubercle down and over quite a bit and brought the patella past that spur, and it was no longer a problem, trochleoplasty not needed. Very powerful operation. So who doesn't need it is a flat trochlea, which you see on the left. Flat on flat can be well balanced, and you do not need a deepening trochleoplasty for that. Also, a patella that sits adequately distal, like you see over here, since you have good overlap, that's going to quickly engage in a groove more distally and be fine. So that's not the indication. So my decision making, I'm always doing an MPFO reconstruction with this this procedure, always, but a deepening trochleoplasty would be done with type Bs or Ds with a convex trochlea, not just flat, and a spur height that's significant, greater than seven millimeters, and a jumping JSON on exam, and especially if I've got significant patella alta, because I know that's going to have even more influence, or I'm going to have a quicker trigger on revision procedures that have already failed a well-done operation. There's a couple of ways to do it, two general types. The thick shell technique is a du jour method that I do. Schottel has popularized a thin flat technique. I can't compare the two. Here's the thick shell technique. I'm gonna start with an osteotome. I'm gonna remove a wedge of bone all the way around the edge and then I'm gonna plan my cuts. And I'm mostly looking at this line down the anterofemoral cortex and where it intersects the cartilage distally. And that's gonna be how far I extend this shell and cavity that I create behind it. I'm gonna start with a high-speed burr to remove some bone. And I'm gonna come in with this commercially available guide with offset guide. I do not have any relationship with this company, but this I have found as a measure of safety to remove bone and create a cavity and get a uniform thickness of that shell. I only use the five millimeter thick offset. If you do the thin flat method, you're gonna then come with a three millimeter offset too and continue to resect bone until you have just three millimeters of bone plus cartilage. I worry a little bit about heat necrosis with that. Once I've got that, it bounces like a diving board. I'm gonna cut it, this isochondral shell with my 20 blade and a bone tamp. And I'm gonna pack some of the bone in the cavities that are left behind to help fill any voids and especially along the edges to provide lift. And I'm gonna fix my shingles with a number two vipral sutures and tap in suture anchors as you see there. So here's a short video. This is that same patient with the jumping J sign and the arthroscopic view. All of that is sitting anterior to the femoral shaft as you see here. That's over a centimeter sitting in front of the femur. Here I've marked my planned cuts. I'll start with an osteotome, aggressively remove this wedge of bone all the way around, save this bone, mince it up for later. And then I'll start with this high speed burr, the TPS burr, because the other, the drill is just not aggressive enough and it takes a long time to get the cavity going. So I'll get the cavity started this way and then switch to this offset guide. Because it's on a drill, it doesn't remove bone very aggressively. So you have to rotate around a pivot point like a windshield wiper, and then it will thin it to a uniform thickness. It bounces like a diving board. Then comes a 20 blade with a bone tamp. I'll often put an osteotome behind there so it doesn't deflect as far. The medial side always bends enough. The lateral side you have to cut just a little bit as you see up here in the corner. And then I'm gonna pack some of these little pieces of bone underneath the edges so it doesn't collapse at that transition. And I'm gonna place some tap in suture anchors of your choice with number two vicral suture, which is well tolerated by the cartilage and bring them up over each shingle. The more bone I can pack underneath these edges, the more lift I can get in depth in the center. With this, the vicral sutures dissolve after about six weeks and this cancellous bone to cancellous bone heals very readily. And my goal is to drop that spur down flush to the femoral cortex. The bigger the spur that I drop down, you can get some splay at the top, but that seems to be tolerated just fine. So the before and after, you can see how it's dropped down. That's my main goal. And then the sunrise view here looks nice. Depth is great, but getting it down flush to the femoral cortex is the main goal. And then here's three different patients. You can see that the vicral is well tolerated by the cartilage. This would have been where one of the 20 blades went, but the cartilage doesn't seem to be bothered by this. Our results just came out in arthroscopy journal last month. You can look it up, but half these people were failures of prior surgery. And in our group that had deepening trochoclastasis, none had recurrent dislocations. And also we did not have a problem with progression of arthritis on x-rays and very good return to sport and patient satisfaction. So rehab is key. I do all these as outpatients. I did one today, but they've got to start range of motion right away or they will get stiff. If they move right away, they're going to be fine. I do brace them and use a partial weight bearing for the first six weeks, but that's a quick review of trochlear dysplasia. And I think it goes well with the two prior talks we heard. Thank you. David, thank you very much. Definitely great compliment to the other presenters talks. And next up we have Jacqueline Brady, who's going to talk about tibiotubercle osteotomy for the recurrent patellofemoral dislocator. Great, can you see me okay, the slides that is? Yep, we are good to go. Perfect, thanks so much for having me, everybody. This has been fantastic. And I'm glad to be the last one to go because I think I've been set up pretty well here. First, I just wanted to say a word about skeletal maturity because this is not a surgery that you want to do in the very young patient. The tibial tubercle ophysis closes at about the same numbers that you've memorized for your OID exams for the distal femur. And the good rule of thumb is try not to violate a growth center that has more than one year remaining. So you'll be dancing with these numbers a little bit because adolescents are a big part of this patient population. So you want to be careful as you go. But assuming we have skeletal maturity sort of dialed in, there are a couple of major indications for tibial tubercle osteotomy. Malalignment and then chondral injury. And we'll talk about both of those. Coronal plane malalignment, you can see from the door sometimes. This is a patient of Beth's that we worked on when I was a fellow. And you can just see that extensor mechanism turn a pretty severe corner as it gets to its insertion on the tibial tubercle. There are a couple of different ways to measure this. We mentioned the tibial tubercle to trochlear groove distance. Some use a cutoff of 15, some use a cutoff of 20. We've published some literature that these risk factors are probably synergistic. And so if they're ALTA, then maybe it's just 15. And if they're dysplastic, they know that the number that you have might be more poorly tolerated. So it's hard to have a hard and fast cutoff. But the insurance companies are looking for those. So 15 and 20 are good rules of thumb. TT-PCL has been popular, especially in the total knee literature. It's a measure of pure lateralization of the tibial tubercle. It does take three cuts to measure it. So be careful if you're trying to quantify this. But the cutoff is usually 24 millimeters before you call it abnormal. We published some literature that TT-TG is more sensitive to patellofemoral instability than TT-PCL because we think there's something about the dynamic internal and external rotation of the knee that you capture when you cross the joint. But people will talk about this, so it comes up. And then a newer measurement is the relationship of the patellar tendon to the lateral trochlea and lateral femoral condyle as it courses toward its insertion. This, I think, is a really useful tool to add to our toolbox because I know all of us have probably encountered these patients who don't meet our sort of numerical cutoffs, but they maybe have a J sign. And you can just see this patellar tendon that's sort of out in the left field. And so it's worth having that as a backup when you're just convinced that there's something off and that can be an additional factor. I'm not sure we're gonna see it replace the others, but it's a good tool to have. And then there's the J sign. So we talked a little bit about that and I can kind of skip through. But this is the one that Dr. Fulkerson really hangs his hat on as his indicator for tibial tubercle osteotomy. So worth thinking about. This is just a sign that soft tissue's not gonna do the job. You need something bony. So sagittal plane malalignment. Let's change our view now. Look at the knee from the side. Adam Yanke kindly shared this video with me because I used to have terrible rudimentary foot part. But the trochlea is gonna be in red here. And you can see that it doesn't take a whole heck of a lot of knee flexion to get the patella safely within its bony confines of the trochlea and normal knee in terms of patellar height. But if you take that patella and you move it north and you make this a patella-alpha knee, you're gonna see that the knee requires more flexion to get the patella safely engaged in its trochlear groove. And that means that this patient has a really vulnerable, fairly large arc of motion. And so if you add some dysplasia, you add some laxity, you add some coronal malalignment, they're gonna have any excuse to come out. And so here's an example, sorry. Here's an example from my clinic of a patient with ALT that's not an incredibly perfect lateral, but you get the gist that there's very little overlap of the patella with the trochlea, and that patella really has to travel a long way to get engaged. So I cheated here, and I'm showing you the patellar height measurements on an MRI when they've been described on x-rays. So grain of salt here. But this shows you the anatomic underlying landmarks well. The insole salivati is popular with the total knee surgeons, but it measures to the tubercle, and we move the tubercle, and so it doesn't change when we do a TTO. It's hard to know what we did. But you saw in Liza Arendt's study that that was the one that bore out as predictive, not Catan de Champs, so maybe there's something to it. Catan de Champs you'll see more commonly in our hands as a measurement tool. Rolly Bender made the good point that the thing that probably matters more than the relationship of the patella to the tibia or the joint line is the relationship of the patella to the trochlea. But as you might imagine, that gets complicated quickly because in his measurement, this patellar trochlear index, you have to have the central slice that has the patella in it with Blumensatt's line. And some of these lateral trackers, they're nowhere in the ballpark of that central slice. So it gets hard to know in three dimensions how to quantify sort of where the trochlea is and where the patella is and how patellar height is measured. Switching gears, chondral injury is another reason to do a TTO. If you have a significant chondral injury that you're worried is going to become symptomatic, if you're doing cartilage respiration and you want to reduce the forces across your restored portion, it's worth thinking about this. Or if they're already symptomatic, obviously it's a good way to unload. So let's talk about surgical technique. Hold that thought on chondral injury for just a minute. So if you think that you just want to medialize, there's no chondral injury, you just want to correct coronal plane malalignment, a nice flat cut, the so-called Elmsley procedure where you're just rotating on that periosteal hinge and fixing it medially is very effective. Here in the States, you'll more often see the Fulkerson technique where you have a bit of a slope to that cut and you therefore move the tibial tubercle anterior medially. And you can customize this. So you can see the cut here, I can make that steeper if they have more chondral injury, I can flatten it out if they have a really high TTTG that I'm trying to correct. And so it gives you some options there. This approach is either lateral or medial to the tubercle. You'd sweep the anterior compartment fascia off a lot like a tibial plateau approach. It's very familiar. And I recommend two points of fixation because the piece always wants to sort of find its way home if you give it any excuse. The Fulkerson osteotomy has been around for a long time, especially in the States. Fedoriano's study showed that the patients with lateral and distal cartilage lesions had the highest rate of satisfaction after this procedure. And then Beck took that to the cadaver lab and showed that we're offloading the lateral patellofemoral joint and loading the medial patellofemoral joint. So something to think about if you have a full thickness medial cartilage lesion, which sometimes you do if they're scuffing that medial side when they're coming out. Distalization, the technique is very similar. You're gonna do whatever you would do for the coronal plane and then take away the distal portion of your shingle. And then you slide it downstream and fix it. You can either feather this to an anterior point, just like you would do in a Fulkerson or an Elmsley and just crack it all the way through, take away that periosteal attachment, or you can do a step cut and move it distally. Either one is very reasonable, but once you're disrupting that periosteal hinge, you are introducing some level of risk with nonunion or fracture. So keep that in mind. Yang et al took cadavers to the lab with distalization and showed that we load the joint with distalization procedures. But keep in mind that cadavers are rarely anatomically abnormal from a patellofemoral standpoint. So you have relative normal cadaveric anatomy. You're certainly loading the joint when you give it Baja. But in a patella alta knee, are they already point loading their distal patella and setting themselves up for arthritis that way? And can we normalize them? I think the jury's still out. In early practice, I really hung my hat on this study and worried about loading cartilage lesions. And I really would hesitate to do that now because I think that if you're ignoring the patella alta that's driving the instability, you're really doing the patient a disservice because I'm not sure that we've proven this to be the case. Don't forget complications. Cosmetic concerns are certainly common, especially in young, thin patients. They're gonna look down at their tibial tubercles and notice a difference. So warn them about that. DVT rate is about 4% and it goes upward from there if they're on oral contraceptive. So think about DVT prophylaxis. Patella baja can arise if you overcorrect. It can arise if they're just hypertrophic scar formers. So early mobilization is helpful. And then fracture, this is an image courtesy of Dr. Fulkerson, and then non-immune are certainly a concern. So these add some risk to add a TTO, but they can be powerful procedures with patella-formal instability. So pearls. You guys are hearing a lot of sort of, every patient is different. There's an art to this. You have to sort of treat the patient individually. I think if you take broad strokes, we really trust the high-level athlete anatomy and mechanics to be pretty solid. And we'll often just do a soft tissue procedure and give them back their check brain. On the other hand, the ligamentously lax patient, the classic Ehlers-Danlos patient, more is more. We often will realign their bony anatomy in order to capture their patella because we don't trust their soft tissues. And especially if they're also, that can be a very powerful correction. And then if you see asymmetry, realize that patella-formal anatomy is most often symmetrical or at least close to it. And so if you see asymmetry and one side is unstable, you can correct that anatomy and usually make a pretty predictably positive change in this patient's life. Thanks very much. Happy to take any questions. Cool. So great job to our panelists. And I'd like to thank you for giving such great high-level talks. We've only had one question come by so far, and I think David sort of addressed it. The question's from Brandon Luzak. Thanks, Dr. Dedick. What is the long-term risk of cartilage after trochleoplasty? And I think you showed the images looking at that. Have you seen any patients, David, who had an increase in their pain following trochleoplasty? I think sometimes in a malaligned joint, I've found that pain can actually be better because they're no longer edge-loading their cartilage. I have not seen somebody that came up with problems with increased pain. With problems with increased pain. As you said, actually, their pain is typically better. Their pain is typically better. I'm not sure why I'm getting an echo here. I'm not sure why I'm getting an echo here. These people, often it can be life-changing for them. They're profoundly unstable. You put the patella in the groove and give them confidence with their knee, and they previously were socially ostracized. They couldn't do any sports. They couldn't do things with their friends. It can be life-changing for them. I think probably everybody on this panel, that's one of the attractions for patella instability surgery, and one of the things that we really enjoy as surgeons. It can be so transformative for some of these teenagers. And I'm just, in general, the group of patella instability surgeries that we do. Excellent. And again, just if you have any questions, go ahead and use the chat panel to send those over. So the question is for Miho or Beth, or anyone who wants to take it. I know with the ISIS score, physical activity is a big component of the scoring system. And I think our scoring systems for patella femoral risk of dislocations, they've been great to see those come out. And I think they've added a lot to our knowledge. How do you weigh activity level in terms of the decision for surgery for the first time dislocator, all other things remaining equal? Yeah, that's a good question. So, I think first of all, these ones where you're trying to risk stratify are adolescents. So like it's different from other conditions where we're looking at how active, are they an active 40 year old or physiologic age and things like that. Because I think in adolescence, everyone has a baseline level of activity that is pretty high and that they shouldn't be cutting back on the things that they do. And so I think that's a good question. So for me, I have not really incorporated that as much. I've kind of gone mostly in terms of, basically those studies that we had talked about in terms of morphologic factors and patient related factors. But I'd be curious to hear what the rest of the group has to say about this. And to that end, I got the back before you reply, you can maybe jump two things. So, I think the first thing is, so, and also sometimes I guess in a lesser active athlete or lesser active person, when you're looking at things to address the anatomy, even if some of the factors may be borderline in terms of, you know, ALTA or dysplasia, does that make you more likely to do just an NPFL because of their activity level may not warrant a bigger procedure like a distalization or patellar tendon shortening or trochleoplasty for that person? Yeah, that's interesting. Not really. So, you know, I think that in terms of instability, at least the way that I see it and the way the patients present these, it's, you know, it's either unstable or it's not, right? So they can either like tolerate it or they can't tolerate it and it's pretty clear and it's not, and most people are not, you know, they can't really define a threshold where they say, oh, if I stop doing this, then it's fine, at least at that age. I would say it's more likely that certain patients who are maybe borderline but active and have a season or certain time that they have to be back where they're really concerned about having the additional osteotomy or the extra rehab time or the additional risks associated with that. So I would say that those are the cases where I'd be more likely to, you know, have that conversation and pull back maybe a little bit on those indications, potentially with those risks being understood. But in terms of actual physical activity and activity level determining that, I haven't factored that in as much, at least from my indications. Yeah, unmute yourself, Beth. I think Beth is muted. Thank you, Meredith. So I think what Miho was saying and also Jackie said it is that when you have somebody who's a high level athlete and they're in season or when they're, you know, they may be at the end of their season trying to decide what to do, that definitely plays a role. I also think that the athlete, as Jackie mentioned, in general, if they are able to be a high level athlete, they by definition don't have a jumping J sign. They wouldn't be an athlete if they did. They by definition don't have severe pathologic anatomy, most of them. And that's not a never, it's not an always, but it's most of the time. I think most of us realize, and Jackie and I were just talking about this the other day with some physical therapists, that there's really two groups of patients. And there are the ACL looking NPFLs, they're the ACL looking patellar instabilities, the lacrosse players who come off, the football player, the, you know, basketball players who are 15 year old girls or boys, whatever. And they look pretty normal and they really do just need a ligament in all likelihood. I mean, the vast majority. And again, this is a broad brushstroke as Jackie put it. But in addition, they recover like an ACL, which is really nice. They don't have that terrible quad atrophy. They don't have the Baten index of nine. Those kinds of things are, that's a whole different instability patient. And I feel like it's a different class. And so, yes, I think if you can at least start to divide like that, it helps to figure out what to do. And also the NCs and athletes obviously need to have counseling in terms of time to getting back, time to return to sport, because it is obviously significantly less with an isolated ligament. Excellent. So we had a couple of questions. I think one from Jordan Greske and Nicholas Stockwell and are kind of one in the same. So from Jordan, we talked a little bit about stratifying NPFL for certain at-risk dislocators. Is it ever appropriate to add a TTO, DFO, et cetera for patients if the anatomy dictates? And same question from Nicholas, essentially looking at rotational malalignment or coronoplane malalignment. That's a big, that's a big, that's a big topic. Is that the question, in the first time dislocator or is it? Yeah, first time dislocator, primary dislocators. Yeah, that's a big question for sure. The question we've talked a lot about, I think, and again, there are patients who you know are going to recur, you see them in your office and you know who they are. And so on some level, if you know they're going to recur and you know they're also usually the ligamentously lax, they have a lower incidence of chondral injury because it's so easy for them to dislocate and then relocate. So I think a lot of us feel comfortable letting them declare themselves and have a second dislocation and then do the whole thing. But it is a very good question because I think the more you do of this, you do get a sense of who those patients are. And I'm not, I would never say never. I think there are patients who after a first time dislocation, if they meet all of those risks and they have an 88% risk of recurrence, I'm not going to just do a ligament. I'm going to use the same criteria I use to judge the rest of the patients in my practice. It'd be interesting to hear what everyone else thinks. I presented a case like this at one of the ANA courses and I served as an appropriately sharp lightning rod over it because it was a first time dislocator that I ended up doing a distalization TTO for. But Bob Magnuson was there and he's done a lot of thoughtful research about this. And he did that study on the first time dislocator and the nonoperative treatment. And are we really doing them any favors if they go on to not return to sport and to not trust their knee? And he said, well, am I going to really just let this patient have one more instability event before I fix the thing that I know is driving the instability? I think that's where we really need to drill down this literature and add to the literature because we don't have a lot of compelling evidence on who gets what. But if you have somebody with a robust family history of instability and they have apprehension on their contralateral knee that hasn't even come out yet and they're young and they're stretchy and there's all these risk factors piling up and you have some very glaring thing that you can safely fix, then I think you have the conversation. The patient that I mentioned was just sort of barely skeletal in nature. It was a real thing to do from a safety standpoint with the FISAS. She had rehabbed for six months and still didn't trust her knee even though she had her quad back and she had her motion back. And she was just knock your socks off, Ulta. And so I just, I really didn't trust the isometry of the MPFL I was going to put in. I didn't trust, I don't know. I just didn't really want to get her any more chondral injury I think was the bottom line. We know that the chondral injury rate is very high and if somebody is really an outlier, I don't think it's unreasonable to think about correcting that risk factor. But I think you'll find the vast majority of us doing MPFL alone. And I think some of my most difficult patients that I've had to deal with were patients who've had recurring dislocation after primary surgery. And so I think if you want to kind of prevent that from happening and I think you address what you need to address, whether it's a trochleoplasty, your TTL, and to be honest, it sounds crazy. I think some of you may agree that the rehab following the trochleoplasty plus an MPFL is not that different than doing just your MPFL alone. The osteotomy adds a little bit of morbidity and pain early on, but it's really not that much more for that patient than just doing the MPFL alone. So I think I've been also a little bit more aggressive at addressing those things when they need to be addressed. David, we're going to let you get in here. So isolated bumpectomy, not a part of my practice. Is that something that you see an indication? Actually explain a little bit about what that entails and do you ever do that? Not part of my practice. And I'm not sure where it would really fall, honestly, because the problem is not a bump and then it drops down to the cartilage. The problem is the entire osteochondral level was sitting anterior to the femoral shaft. Femoral shaft is here and the osteochondral, you know, the trochlea extends up anterior. So I don't know how you take that bump away, not just have a more distal bump. I just don't understand it, I got to say, and I've asked a lot of people who do it. And the only answer I really have heard them give me is that they just take an osteotome or a burr and just remove or taper it back down, but you still have to navigate up and over further down. It just seems like you violate a lot of articular cartilage. So that doesn't have a role for me. My goal is to take that articular cartilage plus bone and drop it down to the level of the anterior femoral cortex. That's number one. And I'm just looking for, you know, how big is that bump? How high does it sit? Does it truly affect the patella? And if I can't work around it, then I'm going to drop it down. And it's, you know, it's effective. Can I ask a question, David? When you- When you're in the presence of dysplasia, it doesn't mean you need to do it. And there may be some people that benefit from it, but don't have to have it. But there's a very small group of people that I really think have to have it and otherwise just keep failing operations. Sorry to interrupt you there. No, no, no. I wanted to ask you a question about that, because one of the things that I have found interesting is, and I think we've seen it in other joints as well, is that dysplasia rarely occurs on one side of the joint. In general, dysplasia is a bipolar problem. And so you showed a good MRI of what the dysplasia looks like on the patella. And oftentimes when you have a flat trochlea, you have a flat or very large lateral facet that kind of mirrors it and works well. And what have you seen as far as the types of dysplasia on the patella that would make you not want to do a trochleaplasty, because you're going to create a V when the patella doesn't match that, where the patella doesn't have a normal configuration? That's a good question. And I've had a lot of people ask me that. And I think the way to understand this is I take the normal, more normal group that occurs distal, that the patella encounters in distal flexion and articulates with congruently, and I take that shape and I extend it proximally. So that patella that fits distally in the groove is going to be just as happy proximally in the groove, because it's a shamed contour that I'm extending proximally. I'm not changing that basic curvature. And I have not found any problems at all with any that I've done, where the patella then doesn't match the trochlea that I've made. The trochlea contour doesn't change a whole lot. It's just extending the curvature up higher, but most importantly, taking this convex bump, which in no way is congruent. If you remember that one slide that had the sunrise view that looked normal, and then the CT scan that looked bizarre with this convex bump, there's nothing congruent about that articulation at all. So I'm taking that away and at least making that flat or with a little bit of a slope, and it's gonna match what's further distal. So it really becomes a non-issue. I hope that helps. Yeah. It helped a lot. So in our last couple of minutes here, could everyone talk about what they do in the isolated NPFL, right? I guess, yeah, in isolated NPFL, first-time dislocator, thoughts about what you do with the lateral side, release, lengthening, leave alone, and what's your decision-making with respect to that? I can start. I only do something to the lateral side if I need to. I try to make it the last thing I do in the case. If it seems abnormally tight, if I can't lift up the lateral facet some, or if I don't have one quadrant of translation, I try hard not to over-tighten my NPFL. I don't think of it as an ACL graft. You really just kind of set it. You don't really pull it. But it's the last thing I do. And when I do anything for it, I do a Z-lengthening. I try really hard not to leave a gap over there in the lateral release. I do a Z-layered lengthening. And with an isolated NPFL, it's pretty rare that I need it. If I'm moving the tubercle, especially if I'm moving it down and way over, then pretty frequent that I need it. I have a thing I usually say, and it's probably not, it's 80-20 and 20-80. In patients who are dislocators, it's probably 20% of them need a lateral lengthening of some sort, 80% don't. And in patients who are overloaders and now aligners, I think it's more 80% that do and 20% that don't. And there's probably some room in there, but that's usually my feeling, is I have to be convinced in a dislocator to do it. I have to convince myself that they fall into that 20%. And I do it, like David said, I maintain the patella in the trochlea. I don't pull it laterally to give slack to the system and then try to evert it. I maintain it in the trochlea and try to evert. And if I can get it to match and be parallel to the floor, then I don't release it. And if I can't, then I do. And again, most of the time we'll do a lengthening and not a release. But sometimes if I'm doing a simple NPFL, rather than open up that side, I'll do it arthroscopically. And beware in the lax patient, you can really do some harm if you do an exuberant lateral release in a ligamentously lax patient. This does not do any good for them and might create iatrogenic medial instability, pretty rare, but it's ridiculous. Good. Excellent. So any closing thoughts? I think we are at our time here. There are no further questions. And so we are at the 9.30 hour. I would like to thank our panelists, Jack and Brady, David Dedek, Beth Schubenstein, and Miho Tanaka. I learn something every time I hear you guys speak. And so thank you for putting these talks together and educating us tonight. And thank you for your thoughtful and lively discussion. For all the fellows still on the line, just remember to tune in second Tuesday of each month for the ALSSM Fellows webinar series. Our next topic will be shoulder instability with bone loss. And so it should be also another great talk on Tuesday, November 10th. And our telehealth webinar series, October 21st, 28th, and November 4th. This is free to fellows. And again, remember to register and all these things can be found on your learning part of your ALSSM website. Log in. So please continue to join us for these educational opportunities. Again, we thank Meredith Herzog for her help on this fellows webinar series and helping to put things together. Things cannot run without her. She's absolutely amazing. And thank you for everyone for attending tonight. Thanks for having us. Thank you.

surgical procedures

patellofemoral instability

first-time patella dislocations

trochlear dysplasia

individualized treatment

scoring systems

trochleoplasty

distalization

research

rehabilitation