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Spring 2020 Fellows Webinars
Trochleoplasty and Patella Instability 2020
Trochleoplasty and Patella Instability 2020
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Welcome, everybody, to the Multi-Institutional Sports Medicine Fellows Conference. First thing I'm going to ask is for everybody to keep their microphones muted so that Dr. Dita can speak and everybody can hear what he's saying and to help prevent some of that reverberation. This is being recorded. It'll be transferred to the AOSSM Learning Management System and be available. The talks this week will be available next week. The talks from last week are available now. If you have any questions, please submit them on the chat. And we'll try to get them all to Dr. Dedeck. And we'll also have some of our faculty contributions, Dr. Sherman, and I believe Dr. Latul, Farrow, and Dr. Fithian. And I don't see Adam Yanke yet, but Adam, if he comes on as well. And again, if there's any other faculty want to speak up as well, please just let me know. And I'll try to unmute everybody. So without any further ado, we're very fortunate to have Dave Dedeck, who's the Chief of Sports Medicine and Head Team Physician at the University of Virginia, the Defending National Champions in lacrosse, and I guess in basketball too, right? Yeah, I guess so. I guess. That's kind of weak, but you didn't win it this year, but then nobody else did. But he's a professor. Still reigning champs. Yeah, I guess. Exactly. And he's involved as well, for the record. And so David is one of the few people in this country that is doing a fair number of trochlearplasties and for the management of trochlear dysplasia and patellar instability. So we ask him to give his perspective on trochlearplasty and patellar instability. So without further ado, Dave, thanks for doing this and being on board and having your program involved. Thank you. Thank you, Mark. Appreciate it. Thanks for coordinating and initiating this series. I hope it's beneficial, especially to the fellows who are trying their best to expand their skill set despite the limitations on operative ability right now. But this talk, I think, follows Lutul's talk very well yesterday and dovetails into Seth Sherman's tomorrow. Excited to hear him as well. It's going to be a fairly focused talk after I first start with a little bit of perspective on kind of when I think I consider bony procedures in conjunction with the NPFL, Reconstructions for Instability. So these are my disclosures. There are really no disclosures relevant to what I'm going to present. I will talk about a specific tool that's used that Arthrex makes. And they're the only one that makes it, but I have no relationship with Arthrex. I do, however, have a heavy bias in basketball with our national championship team. So patella dislocations. When these occur, it's helpful to think about this. The NPFL, for practical purposes, tears every time. It's also helpful to understand that a knee with normal anatomy, unless something's unusual with the mechanism, it does not dislocate the patella. So some of these re-dislocate, not all of them. And some are really unstable, and others not so. So what should be our threshold to correct the underlying anatomy? And that's where there's not a whole lot of agreement, even among people who do a lot of patella thermal instability surgery. I think it's helpful as you approach each patient to look carefully for malalignment in the coronal plane, genu-valgum, patella alta, and especially atrochlear dysplasia. Now, whether to do something with that information is another matter, but you should analyze each patient for this. So just briefly, because Saskia and I know cover this well tomorrow, malalignment's been defined now by the TTTG distance. That's really replaced the Q angle as a clinical measure. It's important to understand that you want to measure at the center of the tendon attachment on the tubercle, not the high point. You're really looking at a vector. So the center of that tendon attachment's gonna be the point that you're gonna measure this. Another very useful measure was in a paper in AJSM in 2018. It's the patella tendon lateral trochlear ridge distance. This really just gets at the vector. And you look at a tendon draped over the edge like this, you know that that vector is terrible. So the thought of just bringing the patella back with an NPFL reconstruction doesn't correct this, and this is a patient that's probably doomed to fail. And this measure takes the apex of this lateral ridge, and you measure in this direction to the lateral edge of the patella tendon at the first cut of the tendon below the patella. I find I'm using this more and more, and this paper actually found this more sensitive and specific for recurrent instability than the TTTG. So time will tell, but I find this just very useful, plus the gestalt of looking at this image and where is that tendon sitting? And it really tells you a lot about vectors. And patellofemoral instability is all about vectors. Fulcrus gnosteotomy, or AMZ, certainly can be done. Don't be glued to this number alone. You're looking also for clinical indications with lateral tracking and tilt, and especially in combination with other anatomic risk factors. What about genuvalgum? We're gonna look at where the mechanical axis for the extremity lies. Here it's outside the center of the knee in the lateral compartment. You're gonna measure the mechanical axis from the center of the femoral head to the center of the knee and down to the center of the talus. And what is the excess valgus in that knee here? If it's greater than six degrees of valgus or excessive valgus, and that may be a trigger to consider doing a distal femoral osteotomy after you confirm that the deformity is in the femur with a lateral discriminal angle being less than 83 degrees. Almost always it is in the femur, and you can correct this with an opening wedge osteotomy. Understand that when you do the opening wedge osteotomy, because you're swinging the whole leg over, including the tibial tubercle, you're also gonna improve your TTTG by seven to 10 millimeters, depending on how far or how big a correction you're gonna do. If the person has more than 12 months of growth, you can do guided growth and accomplish the same goals with a FICL tether. So patella alta is another really important anatomic risk factor. Historically, we use the Insol-Slavati ratio to describe this. This included the patella nose. The patella nose has nothing to do with the articulation in the trochlea. It is completely non-articular, and so probably not a useful measure. So most people have moved to the Caton-Deschamps index or the CD ratio, and this looks at the articular length of the patella relative to the distance down to the top of the plateau. So it's different from the Insol-Slavati ratio that measure the tendon attachment point. The numbers though are the same. Abnormal or outside of two standard deviations is still greater than 1.2. What's a trigger to change this is another matter. I think a lot of people that do patellofemoral surgery are using 1.4 as a trigger to do something about patellar instability. For me, that's what I use, but I'm thinking about it if it's anything greater than 1.2 with a CD ratio. I'm usually measuring this on MRI. Here, it's gonna be this distance, H, over P, the articular length of patella. But another very important measure to consider is the patellotrochlear index. So this looks at the length of trochlear cartilage that overlaps the patella cartilage length when the knee is in extension. So you need an MRI for this, and that ratio should be greater than 33%. For me, a trigger that I need to think about doing something to destabilize that patella if it's less than 20%. So you could have a high-riding patella, or you could have a short trochlea. Both are gonna have the same effect of requiring greater degrees of knee flexion for that patella to be engaged in a bony manner in the trochlea. And when you're talking about dysplasia, all of this is interconnected. It's very important. Patella alta in particular is tightly connected with trochlear dysplasia in terms of how the dysplasia affects the patella tracking. We're gonna say a lot more about that. But I'm always looking at these two measures, measuring on every patella instability patient. CD ratio and the patellotrochlear index, understanding a short trochlea is just as important as a high-riding patella. Oops. So here's patella alta and the knee in extension. Articular cartilage on the patella, nothing on the femur. Lutul showed a slide like this yesterday. And this is how patella alta manifests. And you can see if you have any additional malalignment or genuvalgum, that's gonna really compound this effect in terms of the way that patella's gonna track. So I'm gonna consider distalizing the patella for these patients. If I have a large amount of distalization to do, then I'll calculate this. It's a simple calculation to get a goal of a CD ratio of 1.1 post-op. And here you can see a fluoro shot. So if it's a big correction, like a centimeter or more, then I will take a wedge of bone out of the desired amount, slide the osteotomized tubercle down to the docks and transpose that piece of bone up to fill the gap, tamp it in place. And of note, I almost always use three screws now to fix my tubercle. This cut down here takes forever to heal. Easily six months to heal. It is a stress riser. Don't go too deep with this cut. I know Seth will talk about this tomorrow too. It's also possible, and my preferred method, if it's a less pronounced distalization, like seven, eight millimeters or so, is to just feather this cut and overlap it. And again, I'm going to three screws almost always. And just as an aside, I don't wanna steal Seth's thunder, but I have seen this shingle split like a block of wood, and sometimes you don't notice it till later. So I'll put the third screw off axis so that doesn't become an issue. So trochlear dysplasia, if you look at the papers that look at anatomic risk factors and recurrence for patella stability, dysplasia is bubbling up as the key risk factors among the various ones you can measure. In the dislocation group, this is a very good paper by Liza and found that 74% of the people in the dislocation group had dysplasia, only 4% in the control group. High TTTG was almost never seen as a solitary risk factor, and patella alta was also a common risk factor seen in the control group. So, and other papers like this have shown that dysplasia is probably the key thing to appreciate. So first thing is you gotta be able to recognize it. The lateral x-ray is the key to identify trochlear dysplasia. And let's first go through these lines so everybody understands this. So my, all right, I'm gonna try this here. Annotate, and so this is Blumensat's line. As Blumensat's line or the notch comes out to the articular margin, that is where your, where'd the mouse go? That is where the base of the trochlear groove is. The mouse disappeared, sorry. That's weird. All right, that's different. Well, I'm gonna pick it up here. So this is at the exit of the notch, this is gonna be the base of your trochlear groove. And as you come proximal, that's the blue dashed line, I don't think I wanna do annotation anymore, but that blue dashed line where it crosses your red line, which is your, the height of your medial and lateral trochlea, where it crosses, where it meets that is gonna be flat. And if it continues to extend anteriorly, that is gonna be the spur sitting in front of the femoral shaft. So let me go back to the mouse, there we go. So if you think about this coming down the anterior femoral cortex, anything that sits in front of it is a supratrochlear spur. So the lateral just clues you into the presence of a spur, but this is gonna be the base of the trochlear groove, at this point it's flat, and now it continues anteriorly and potentially is convex. So you no longer have a concave surface, up here you're gonna have a convex surface. This is, so it's not about the sunrise view. Let me get rid of that. Okay. This is the same knee, okay? 45 degrees of flexion, a merchant view, and this looks like a reasonable trochlear groove, and I would agree that it is. This is the same knee in extension on a CT arthrogram, and look at this crazy convex trochlea that you have there, and this is like an egg on a table, which way is it gonna go? So this is not the view that you use to assess patella femoral dysplasia, it's gonna be your lateral view to show you the presence of a spur, and then your axial view on three-dimensional imaging that's gonna really help you understand the shape of this spur. People also ask me about, well, gee, you're gonna be changing the trochlear groove, what about patella congruency? Is that not gonna fit anymore? Well, this is again, is the same knee. See, the patella is shaped to fit in the trochlear groove where it makes more contact and deeper flexion, where the contact pressures are greater. Out here in extension where the contact pressures are less great, the patella doesn't articulate at all in a way with much pressure on that surface. In fact, you can see the beginnings of chondromalacia, or loss of cartilage thickness here at the apex of the patella, and incongruity even there at the patella, where it articulates on this bump. So what I'm trying to do with a deepening trochleoplasty is extend this shape approximately to here. And so it will naturally dovetail with the patella shape. And it really becomes a non-issue. I've never seen a problem with the patella not articulating with the deepening trochleoplasty groove that we achieve. But this, I think, is very helpful to understand. This view is not how you're gonna be assessing the presence of patella trochlear dysplasia. Next, we wanna quantify this spur. This is something that's not talked about much, but how large is this? Not just a de jure classification, but we're gonna drop a line down the anterofemoral cortex and then measure how tall this spur is, because all of this should be flush with the anterofemoral cortex. A normal trochlear groove comes up at a Blumensatz line, curves anteriorly, and is flush with the femoral cortex. That's the normal anatomy. All of this is sitting proud, and you do it at the cut on the CT or the MRI where you have the cruciate ligament. So that should be the center of the notch. So here, I've seen it on x-ray, drop a line down. I see it extends anterior to the femoral shaft. Then this is a spur that's a super trochlear spur, the crossing sign where they meet, and then I'm gonna go to the MRI, and I'm gonna measure how tall this spur is, and it's gonna be bone plus cartilage, and that's the spur that the patella has to navigate. The MRI criteria for dysplasia in the literature is gonna be a spur height greater than five millimeters and a sulcus angle flatter than 145 degrees. The other measures are gonna be looking at trochlear depth. So you're gonna take the average of your lateral and medial trochlear heights and subtract from it your trochlear height in the center of the groove, and if it's less than three millimeters or flatter than three millimeters, that qualifies as trochlear dysplasia. When I'm doing a deepening trochleoplasty, these are generally gonna be convex surfaces, so it'd be a negative number. The other feature is a very short, a hypoplastic medial facet in almost all of these, a much more pronounced lateral facet, really hypoplastic medial facet, less than 40% of the length of the lateral facet. The de jure classification is qualitative, but not quantitative, and it really doesn't tell us who needs a deepening trochleoplasty. It is very helpful for just getting your mind around the different shapes that we have. So type A is basically flat, I'm sorry. Type A is basically flat. There may be a minimal bump, but it's just a relatively flat trochlea, and that is not a worrisome problem and does not need a deepening trochleoplasty. Type B has this crossing sign and a spur that extends anterior to the femoral shaft, and that bump can be big or small. So type B is categorized as one of the severe trochlear dysplasias, but it doesn't really quantify it. Measuring the spur helps us quantify it and get at who needs a deepening trochleoplasty. Type C is a very strange shape where you have this tall lateral side and extremely hypoplastic medial side, but technically there's no spur or bump that sits anterior to the femoral shaft, so a deepening trochleoplasty doesn't really make any sense. So even though this can be very dysplastic, there's not a bump that we can drop down, level to the anterior femoral cortex. If the normal anatomy is for this trochlear groove to come up flush with the anterior cortex, that's really as deep as we can drop it. So if it's already starting there, I can't drop it any lower. Now type D puts the C and the B together. It's got this convex shape up here, a very hypoplastic medial side, but it does have a spur that sits anterior to the femoral shaft. The type Ds are really the ones that you need to consider deepening trochleoplasty, and also the type Bs that have a tall supertrochlear spur. So the next question I think is the really important one. So you've kind of identified some dysplasia, and now you gotta say, well, does that spur influence the patella? Do I need to do something about it? So this is a very pronounced J sign on the right, and the arthroscopic view from the superior portal, superior lateral portal on the left, and watch what happens when I just externally rotate the foot just slightly and flex the knee. Of course, no quad tone, watch this thing jump over. And that's what happens with a J sign, And you can see the chondrosis, and this is a petite 19-year-old female. Look at what they're already doing to their cartilage. And you notice that this is a very convex, this is looking from above, very convex shape and a big spur that sits in front of the femoral shaft. None of that should be there. That should be flush with the anterior femoral cortex. So this spur really profoundly affects the patella, and you can see it on the exam with what people are now starting to call a jumping J sign. When you see this, it's unmistakable in the office. Some people have a more softer J sign, which is very important to note, but a jumping J sign is extremely important. So what does that mean? What's J sign? Well, that means the patella leaves the bony restraint of the groove in full extension completely, and is coming out sideways. It'll do more or less of that depending on other factors like how much genu-valgus that they have. So this either means significant patella alta or trochlear dysplasia or both. And this combination is especially important because this spur is gonna have much more influence. So without the deepening trochleoplasty, back to our image here, which way is the egg on the table? Which way is the patella gonna go? And these people are gonna have profound instability. So the next question, I say, okay, this spur really affects patella tracking and deepening trochleoplasty is not a procedure that many people have experience with, so, and there may be more risk than perhaps doing an extroarticular procedure, I would definitely say that's the case. So, now I ask the very basic question, well, can I work around it? Can I somehow overcome this problem of dysplasia without doing a deepening trochleoplasty? And here's a great example of a case like that. This person had a big jumping J sign and has a six millimeter spur, so not real large, but definitely a spur and abnormal anatomy, but the patella trochlear index is almost zero. So, even a moderate size spur has a lot of influence to the patella because it's got to navigate the front of that spur every time the knee bends. But there may be another way to get around this. So, this, those would be categorized as type B, six millimeter spur, CD ratio was very high, 1.5, zero for patella trochlear index. They also had coronal malalignment, elevated TTTG, look at where the patella sits in extension, look at this lousy vector where the tendon's pulling it. So, I can get around the spur by distalizing and medializing my patella tendon attachment. And now, that patella does not have to navigate that super trochlear spur every time the knee flexes. So, I moved this, I think I moved it down 12 or 13 millimeters and over, over about the same, and there you can see the three screws, and I tried to fix one out of phase, and then the trochleoplasty was not needed. So, very helpful to, another way to think about doing this. So, who doesn't need it? Okay. Just the mere presence of dysplasia, here's a dysplastic trochlea with a bit of a spur, but a great patella trochlear index. So, very little flexion in this knee is going to find the groove. All of these patients have a groove down here in deeper flexion, except for the very, very unusual patient who has flexion instability. I think that's really beyond this talk. But flat on flat is not a problem. So many patients get sent to me because they get this view and say, I've got a flat trochlea, you may need a trochleoplasty. That doesn't bother me at all. Flat on flat can be well balanced, especially if the coronal alignment is good and the vectors are good. You can probably do an isolated NPFL for this patient and do just fine. Flat on flat is not a problem, but when that patella is sitting high and it's got to navigate that bump every time, that's a different matter. So, my decision making is I'm always doing an NPFL reconstruction with this operation. I'm going to consider a deepening trochleoplasty when I've got a type B or a D with a convex trochlea, not just a flat trochlea, and a significant spur height. And I've gone to where now 7 millimeters or greater, and often I'm talking about 9, 10 millimeters of a bump there. And then it's very helpful for me to see a J sign on exam. That tells me that spur has a tremendous influence on the patella tracking. And if there's some patella alta or short trochlea, you've got these borderline cases of patella trochlea index and CD ratio, that's the person I'm going to be doing a deepening trochleoplasty on. The other thing to consider is also in revision procedures where they have dysplasia. If it's failed once, that knee is telling you that that dysplasia is important, and you probably ought to consider addressing it the next time. So there's a couple of ways to do this. There are more ways to do this, but two popular ways to do this now. The first I'll describe is what I do is the fixed shell technique, which I learned from David Dujour. And it utilizes a 3 to 5 millimeter osteochondral shell that we're then going to crack with a 20 blade and fix with absorbable sutures draped over each shingles, each of the shingles and fixed with knotless suture anchors. And this little animation kind of gets at the idea of we're going to create a cavity behind this bump and then drop it down. The other is the thin flap technique that Philip Schottel has popularized, or the barrier thin flap technique that's going to thin this out to just 2 to 3 millimeters of an osteochondral flap. They're going to peel it back, really make it thin, then shape the bone beneath it, and then fix it with vicryl tape. This is done more in Europe. Europe has vicryl tape. We don't have it in the U.S. You could, I guess, use a number two vicryl the same way. I don't know anybody that does both methods and could comment on advantages of one versus the other. It's kind of what surgeons have learned, one direction or the other. I think both work, both accomplish this, and there are pros and cons to each, but I'm going to focus on the thick shell technique, and if we have time, I'll show a video from Philip Schottel that he loaned me that gets at that technique. So the thick shell technique, the du jour method, the osteotomy method, all of those are synonymous, starts with an osteotome, and I'm going to try to drop this new groove I'm going to make flush with the anterior femoral cortex, so I start well back where the femoral cortex is flat, and I'm going to cut towards the trochlear groove this way and take a V-shaped wedge of bone out. This coming from the top starts slightly onto the articular cartilage as well, so that you can get it flat again. Save that bone. Take it out with the osteotome and then a ronger, be aggressive reaching down into this cavity that you're going to create with a ronger, save those pieces of bone and mince them up. You're going to use them later, but the goal is going to be to take this groove and then drop it down and make it flush to the anterior femoral cortex. Next we're going to plan where the cut is going to be. So the blue line here is the anterior femoral cortex. If I extrapolate that down to where it intersects the articular cartilage, that's going to be the distal extent of the cavity I create or the osteotomy. I map out the prior center of the trochlear groove. Quite often in these dysplastic trochleas, that's abnormally medial. You want to create your new trochlear groove in line with the femoral shaft and basically lateral to improve your tibial tubercle trochlear groove distance. If I move the tubercle medial, it reduces the TTTG number. The same happens if I move my groove lateral, that also reduces the TTTG number. So it's a little counterintuitive, you think about it, it makes sense. So this can be easily done and usually six or seven millimeters even, you can lateralize your groove and reduce your TTTG. Now where the osteotomy or the cavity ends on each side is going to be the inflection point. So where this curve transitions, this big yellow arrow, where the curve transitions from going up to going down, tends to be the natural inflection point and that'll be the distal extent. So I'll mark it out like this with the dots. And then I'm going to create a cavity underneath this space and then drop this down. I start after the osteotomes to get the beginning of this cavity, I start with a high-speed burr on a TPS device, I use a three millimeter oval or three millimeter egg burr to start to remove the bone. After I've got a working space underneath there, this is a straight tool and it's very hard, this is all I had at first, it was very hard to follow this curve and I worry we risk perforation of the cartilage or heat necrosis. So then I do switch to this commercially available guide. Again, I don't have any connection with Arthrex, but this is a useful guide and I do think it is, for me, it has made the surgery safer and I think it's an easy way to learn. You could start from this, start with this tool from scratch, but it takes a long time. This is attached to a drill, it's not a high-speed device, it very, very slowly removes the bone. Getting started here and then fine-tuning with this is much easier. And it has two different offset guides, one can be five millimeters thick for your final shell, the thin flat method switches out for the three millimeter offset so you can make it even thinner, but it requires a lot of work to thin it down. Now you'd like to think that you could just sweep it side to side and remove the bone and thin this out, but because it's on a drill and it's spinning more slowly, it doesn't work that way. You have to do it around a pivot point. So you think about that as your pivot point and you swing the drill hand back and forth and you can remove the bone that way like a windshield wiper. It takes a little while to do, so I definitely recommend starting with the high-speed burr. And then you've got the cavity that's created all the way down to the margins as you've marked out. Then we're going to crease it where we want this thing to bend. We're going to take a 20 blade and a bone tamp and we're going to cut right down the center where we want the new groove to be through the osteochondral shell. If I've got a big cavity like this one was probably 11 millimeters or so of a spur, so it's a big cavity when I'm left with the shell, I'll put the osteotome behind it just to brace it because otherwise this will bounce like a diving board and if it deflects too much, I don't want it to crack, the shell to crack over here where I don't want it to. I'll make the center cut all the way up through and then for most of these, I'll then also make the cut on the lateral edge. Now you don't want that cut to connect with the center cut or you've got a free piece of bone and then you're breaking out the headless compression screws and scratching your head. But you do want to cut just that lateral edge and then at that point, everything's malleable. The medial side, you almost never need to cut. It's always supple and malleable and you can just press down with your thumb in the center of here and reshape it and the lateral side just needs just to be cut up here at the top and then you can often bend it down into the new shape. Those pieces of bone that you messed up from the beginning, you can then pack underneath the edges and into any voids that you've created as you were doing the burring. This helps with this transition because without that here in this void, I have seen a couple of these where the transition from unresected bone to the cavity is, I've seen that settle. This is out of the periphery. It didn't matter clinically, but the x-ray doesn't look as good. So I've learned to put the bone underneath there and it solves that problem. The other thing that does with these little pieces of bone that you pack in is it can give you a little bit of lift, especially coming proximal because this operation does a great job of making this flat at the top, but you don't really have a groove at the very top unless you put some bone along the edges on both sides to give you a little bit of depth. Now the normal trochlea does end basically flat, but it's nice to extend that depth and that groove approximately some and you can certainly fine tune that. Then we're going to just fix it in place with, I use number two vipral sutures, I use two of them, and you're going to fix this with knotless suture anchors. It doesn't matter what the brand, I've gone to these 2.9 millimeter tap-in knotless suture anchors. When I first did this, I was using threaded. Beware that this bone in the distal femur is not like a humeral head, which threaded anchors are designed for, and you have to tap up an extra size or else there's too much shear and the absorbable anchors will want to crack. That's another reason I've gone to using tap-in anchors, but the 2.9 anchor just distal, not in the cut line, but just distal to that cut line. Tap it in. I use two of the number two viprals in case one breaks and bring a pair of each over each shingle and you can kind of fine tune this, move it along that edge to where you want to optimally compress that shingle to give you just the shape that you want, move it closer or further from that center line, and then fix it to another pair of knotless suture anchors up top. The synovium I had dissected back at the beginning. You see the Lovejoys holding it back here. I'll leave these tails on, take a free needle, bring it up through that synovium and tie it down right at the edge of the articular margin. It helps to cover that up and that bleeding surface maybe reduce some of the scarring. And this is a before and after, and you see it's dropped down flush to the femoral shaft. You see the ruler measuring as at least a centimeter of spur and now it's down flush to the femoral cortex. And this is a before and after sunrise view. And this is really what we're after here. What about that suture on the articular cartilage? This does not seem to have any negative effect. The suture is pretty much dissolved in the interarticular environment at about six weeks. This was, excuse me, this was the anchor point where the anchor was placed, and you can't even see any hint of suture or issues on the cartilage. This was probably my center cut, but the cartilage, this is three different knees. You can see it's tolerated very, very well, and so not a problem. I've also had no problem with loss of fixation. So here's putting it all together. This person's asleep. This is a 19-year-old petite girl. She was a lacrosse player. Look at the chondrosis she already has. Look at the size of this bump. And then we're going to draw it out, start with an osteotome, remove this bone, get in there with a ronger, and I'll reach pretty far underneath with that ronger to take pieces of bone out. And here comes the high-speed burr. I'm going to put it on the outside to give me an idea for how far I can safely go. This is a pretty aggressive tool. And you can also deepen the center a little bit so that you have the ability to drop the center down slightly. And here comes the offset guide. And you get, this is a different knee, but you get the idea for how you work it like a windshield wiper, and now it bounces like a diving board. That's exactly what I want. Here comes the bone tamp and the 20 blade, and we're going to crease it. You see how malleable it is, and I'm going to pack the bone underneath, and I'll even mince it into more small pieces than that. That may be go up along the edge, and I'm going to place a tap and anchor with the sutures on it. You see, I just cut slightly the lateral side. That's all you need usually. These can get tapped in. The more bone you can put along the edge, the more depth you can get here. But you can see that's down flush. Sometimes you get a little opening, a little gap here at the top, depending on how big that spur was. It doesn't seem to matter at all. Vitella only contacts that in extreme extension, very little compressive force, haven't seen any problem with that. So what about rehab? I do all of these as an outpatient, even in combined procedures, if I'm doing something with the tubercle, regional blocks, sometimes with a nerve catheter, but they all go home. They start physical therapy right away. I have learned that it's important to encourage immediate motion. The biggest complication I had was stiffness. Early when I was into this, I was tentative, and they were in a brace and would lock them initially and slowly move them, and they got stiff. That's a big, raw, bleeding surface where that burr has removed the bone. Along the edge, you get very dense scar tissue right along the articular margin of the trochlea, and they just get stuck. So early on, we had some that we had to take back for license adhesions and manipulation. They got their motion back fine, but I've learned to just, when I'm talking to people in the clinic beforehand, really help them understand the importance of moving right away. If they move in the first few days, they're home free. I do brace them for a fall risk. I'll often go zero to 70 at first for a little security, but have them taking the brace off for motion beyond that first two weeks, but certainly letting them open up to 90, and they can even move beyond that with the therapist. Motion is not a problem. And I do 50% weight-bearing for the first six weeks, and crutches, and then they're off crutches. By three months, this is healed. Their NPFL is healed, and in my mind, it's just about strength return, and they're getting back to sports by five to six months. I have had collegiate athletes return. Now, do collegiate athletes come in with dysplasia of this degree? No. I don't think people with this degree of dysplasia to need this procedure have the ability to athletically get to a collegiate level. It's just prohibitive, the instability. But I've certainly seen a lot of high schoolers that have then gone on to collegiate athletic careers. But in general, this is for somebody with really profound instability, and they're just so happy that the patella is back in place, and it can be life-changing. Most of the patients I do it on are teenagers. You cannot do this procedure on somebody whose growth plates are wide open. Think of it just like an ACL operation. The person that you would pause for a BTP graft because of their physis is probably too young for this procedure. Once they're in that last six months of growth where you think the BTP would be safe, same with this. But you can have a little bit of open physis. The other thing you can't do with this procedure is for somebody who already is arthritic. The osseochondral shell has to be supple. Once they're arthritic, that ebranated bone is sclerotic, and it's going to crack wherever it wants to. After you create that cavity, you're going to put the 20 blade on it, and it's going to crack just like a split of wood, like you split wood. I started and have been keeping a registry of all my patients. This was last year at AOSSM, I presented on my patients, and I'm now over 100 total. But this was in the registry we had out longer than two years, and they did extremely well. I've had nobody have a recurrent dislocation, knock on wood. Half of these people were revision of some prior patellofemoral instability procedure to start with. A lot of patients referred in, so half of them had already failed procedures, but nobody had recurrent dislocations. You saw examples of some of the crazy anatomies, so this is a very effective procedure when it's indicated. One person had a mild J-sign with some apprehension, that person also had a lot of genuvalgum. It's hard to know when you need extra procedures, that's what I did for her to solve that later. But in general, very good patient satisfaction, return to work, return to sport, and improvement in terms of these numbers. Importantly, the KL grade in terms of arthrosis did not increase, basically the same. So it did not worsen over time, and I have people out now to nine years. So this is the thin flap technique, just for your understanding. So Philip does this for a small lateral incision, and then he puts these K-wires in his retractors and starts with the osteotome to create the shell, this is coming from the lateral side. And he's going to make this thinner and thinner after he starts with the osteotome, and starts with the five millimeter offset and starts to thin it. And then it's getting thinner still, now it's going to go to the three millimeter offset. And this takes some time to thin this out. So now you can see how malleable this is, and it's like lifting the hood of the car. And he's going to then plan where he wants this to crease. Now, I'm just going to pause this for a second. My concern is what happens at that hinge point across there on the articular cartilage. So I don't have experience with this, but that's my concern. My other concern is heat necrosis, because I know it's hard to really control your tools, and the thinner you get, maybe the more risky that gets. The drill and the offset guide is certainly less prone to heat necrosis than is the high-speed burr, but those are my two concerns. This then allows him to take osteotomes and reshape the bone beneath it, and he creates a groove. So he'll fine-tune it and then mash this very malleable shell into that groove he created beneath it, and then he's gonna hold it in place with Vicryl tape. I don't have any experience with Vicryl tape. Again, this is not available in the U.S., and it's really remarkable how well the knee tolerates his Vicryl sutures. So I'd assume the same is the case for the tape, even though you'd think, my word, what's the patella gonna think of that underneath it? But I just don't think there's as much compressive force out here in extension, and you've got these people on crutches anyway, and it's gone pretty fast. This is just such a robust, bleeding bed environment. It heals quickly. I think he's putting some fiber glue on the edges there, but you get the idea. So loss of fixation and healing doesn't seem to be a problem at all. These heal readily. That's it for the trochlear dysplasia. I was just gonna share one thing that came up last night with Lutul, and we were talking about different ways to fix the graft on the patella, and I think my comments might've been misinterpreted, and I thought it'd be helpful to share this. I know a lot of people put anchors here on the side of the patella, and I'll often do that, but I find you can do drill holes in the patella that do penetrate the anterior patella cortex, and you can do it safely. Now, the original papers with fracture risks dealt with a 4 1⁄2-millimeter drill bit that went all the way across twice. That's a different thing, but I will drop my hand as steeply as I can and use a 3.2-millimeter drill bit. Then I put the beef pin in to help me gauge the angle and go a centimeter distance, so it looks closer than it is, but there's an adequate bone bridge of a full centimeter. I'm working on the top half to top third of the patella, and it's right at the articular margin here, and I drill as steeply as I can out the anterior cortex of the patella, and then I'll take the gracilis. The gracilis is my go-to graft. Rarely, rarely do I need a semi-T unless there's a problem with the anatomy, and pull it through with the beef pin, and then you save yourself the cost of two suture anchors. Those of you who are going to be in your own surgery centers are going to really appreciate that soon when you're saving $800 a case. And there's, down here, the two free ends, and I put my pin in under fluoro at shovel's point, and I wrap these around the end, and always watch the tracking. Make sure I've got it exactly right. If I don't like it, I can easily move the pin. I haven't committed that tunnel. Then I'll create the tunnel, pull it in, and fix it with a single absorbable interference screw, so just wanted to share that technique. And just as an aside, we have our series of these going through the publication process. Some people are a little skeptical about the fracture risk, so we had nearly 500 people with groups, both suture anchors and the tunnels, and nearly 300 in the tunnel group, which is this. One fracture in 300 people, or 277 people. That person fell directly on their knee about three weeks post-op, and these people do fall, that is a concern, but it's not like this is a major fracture risk, and actually had fewer complications, fewer revisions, and less recurrent instability in the patients who had the looped graft technique, again, all with the gracilis, then with the suture anchors. I think there is a percentage of these suture anchors that can fail. If many people out there have done more than a handful of these suture anchors, which are designed for a glenoid, it's very different than the medial patella bone, you put some in, and you test them, and sometimes they pop right back out. If you haven't had it happen before, it certainly will, and so you wonder if that could happen sometimes with some of these patients. But anyway, this is just another way to do it. I think the key is on the femur, where you put that graft, but I'll stop here and take some questions. Dave, that was phenomenal. Thank you very much. Really fantastic talk. I got a quick question for you before we get to the first question from Matthew. You said you went to three screws, and I know you said that doing the distalization osteotomy, and I know Seth is gonna be talking a lot more about the osteotomies tomorrow. I don't know how much to distalization, but you said you've gone to three screws, and you said that it's delayed healing. I mean, have you had hardware failure that's led to an union, or what, that you've kind of gone to three screws? Because one thing I worry about is that size of the bone, you run a risk also potentially of cracking the bone, so, or stress rises from having three. So what's the story on that? Why'd you change to that? So what prompted me to do that is I had a couple of cases, especially where you have a tapered shingle, where you put this bottom screw in, and it's not maybe sitting flush, because you've moved it over on the hinge. And as you compress it down, I've had a couple where the bone would start to crack, the shingle would start to crack from distally up to that screw. And then it wants to continue to propagate. And I had a couple of people where you saw it continue to propagate on an x-ray, and then it's a race to healing versus whether that's gonna continue to propagate. I didn't have any loss of fixation. I didn't have to revise them, but it got me concerned. And so I just started to put this third screw off axis. The other thing is sometimes these take a while to heal. I mean, there's metabolic factors and so forth. And especially if you're doing a distalization, this can easily take six months to heal. If you distalize it and overlap it, that can take a long time to heal. That distal cut is all cortical. And I just like the additional security of a third screw. I'd say probably 80% of the time, I'm not using a third screw. And that's a change for me in the past two years. Because I mean, I always go to, but I do go off axis so that, you know, as my standard, but let me get to this question by Matthew. So what is it about the du jour type C that does not cause a supracondylar spur compared to a B and a D? And what is your approach to management of the du jour C, especially in the revision setting? Great question. So a C technically doesn't have a spur. There's no additional bone or spur sitting anterior to a line that's dropped down the anterior femoral cortex. So technically I can't do a deepening trochleoplasty because I'd drop it down below the level of the anterior femoral cortex. It tends to have a convex or high lateral trochlear edge, but a very hypoplastic medial side. And if it's a revision setting or somebody with a really profound instability, I'm gonna look for some other work around like I talked about before. Maybe that's patella alta, maybe it's falgus, maybe it's coronal malalignment, but some other osteotomy that may help stack the deck for success with MTFL reconstruction. So when, you know, David and I go way back when I was in Pittsburgh and he had come to Pittsburgh at that time. At that time, before he was doing the deepening trochleoplasty, he was actually elevating the medial and lateral edges and making a trochlea that way. And he experienced with trying something like that for the type C since you can't lower it anymore about raising the edges. And I haven't ever really spoken with David other than he felt like the deepening has done better than the raising. But if there was other reasons as to why he went away from the raising the edges. And maybe Don, who spent some time in France as well, might be able to chime in as well if he knows any reason why. I would certainly welcome Don's comments, but I have no experience with that, number one. Number two, I think you really risk creating incongruity if that's the approach. Because then we're not really trying to extend the shape of the groove from down here approximately just by deepening it, you're elevating it and creating a whole new shape. And I think that could be a potential problem and you'll probably end up with point contact in just certain parts of the newly created groove. And that could really lead to chondrosis. David, if you have a C, the center of that groove is more medial so the T2G is tending to be elevated. There's a lateralized force vector. In my thoughts and opinion, that may be one, albeit rare indication for medialization tubercle osteotomy to help solve that problem in failure of soft tissue or other. Good point. Whereas I think that's falling out of favor in a very big way for other variants of trochlea dysplasia or other instability problems in general. So I use it there. David, it was a great talk. I would, just showing your illustration there of David's classification, if you look at the lateral edge, you wanna leave that as high as possible. And you showed that in your video. I think the audience really would do well to pay attention to that. You're not removing bone at that lateral apex. You want that to stay as high as possible because that's your constraint. Yep. So basically, so you're dropping that center down. And one other point that they may have missed is that you mentioned this as well, that that ridge that's where the dysplasia starts is often more proximal than the articular cartilage. And you may, I've had that ridge go up three to four centimeters above the articular cartilage. And so I'll make an incision high enough to clear that all the way down to the anterior femoral cortex and give myself a target for where I want the center of the groove to come down to adjacent to the end, what would be the projection of the anterior femoral cortex. You made that point. Exactly. Just a point. Yeah, I'll probably be honest with you, John. Yeah. Yeah. Okay, Adam, you had a question as well. You wanna? Sure. I guess there's kind of two questions. First of all, great talk, really amazing. And I'm still learning quite a bit about this. You know, I've had some patients with really severe type D trochleas that have a pretty major cliff. And then they also have an irregular trochlea distally as it enters into the notch where there's almost blistering or like a nodular appearance to it. I was curious how you've approached those and if you've experienced that. I have seen some of that, Adam. That's a tough problem. They're getting basically secondary arthritic changes. It can be from too much or too little contact even in terms of the nutritional effects on the cartilage. I can't safely come very far down around that curve. I really try to limit it to this line extended down the anterior femoral cortex or just slightly further. And, you know, I think once you've done that and the spur is gone and you've restored stability with an MPFL reconstruction, these patients are still very, very happy. I mean, it's life-changing for these people with this big jumping J sign to have this patella back in a groove and a knee they can trust. But I don't find I can do much with it. I'm afraid to do any associated cartilage procedure down here. I certainly can't do a cartilage procedure on the flap to speak of at that time, or not when I can feel safely. You can do things on the patella perhaps if you need to, but rarely do you need to even do it. I mean, these people are so much happier with a stable patella. I think it's easy to be, to over-treat patella femoral cartilage lesions based on their MRI appearance when they have profound instability. You restore stability, they are happy, happy people and they get back to activities. Great, thanks. Awesome. And not to steal, well, actually, first of all, Seth, I'm, you know, I know when I've, you and I have talked a little bit about, and I've tried to send you somebody for a trochleoplasty. Yeah, you're not as aggressive about doing the trochleoplasty, you know, in the spectrum of the du jour Bs and Ds. You wanna kind of comment on that? Yeah, I think similar to Adam and others who are in our mid-teens at this, I think we're paying very close attention to David and to our European colleagues and others who do this more regularly, but haven't jumped in with any regularity. I'd also, you know, even point out other mentors like John Fulkerson and others who never do trochleoplasty. So I think, I guess I can push that back to David. I was gonna ask for the fellows and for myself about learning curve, you know, issues. And, you know, I think, you know, just how would you go about safely implementing this and what frequency do you, you know, really do this in your instability patients? You know, is it 20%, is it higher than that? Or is it still a pretty small number? Because I think we can get a misconception you know, here in America. Yeah, absolutely. It's still a pretty small number. I do probably one of these a month. I have a very heavy patellofemoral practice. Easily doing three or four patellofemoral instability, patellofemoral PF instability cases per week. And doing it probably about one a month. So I've done about 100 over nine years. I tiptoed in. The first patient I did had already failed four operations and, you know, had horrible anatomy and was like 41 years of age. So that was, I think, an ideal first case because if all goes wrong, they're not that far away from arthroplasty age. But I just followed David DuJour's lead. I learned from him, picked his brains, videos and things. It's very difficult to mimic this in the lab, unfortunately, because you can't find this plastic anatomy like this on the cadaver to do it. And if you have normal anatomy with a groove that comes down flush to the dermal cortex, it's hard to reproduce this operation. But you can, you can create a cavity and you can just work the tools and work that offset guide and get the hang of it. But I hesitate to say this, but the technique itself is not that hard. I mean, we do a lot more difficult procedures. I think the harder thing is decision-making. And, you know, I'll be the first to admit, I don't think we have it sorted out. I mean, you can have people at each end of the spectrum and we may try workarounds to the point that, gosh, it may not make sense. It would have been much better to correct the anatomy by dropping this down. And other times maybe we can be too aggressive with it. But I just try to go back to those principles and that's nine years of experience. And I think my thinking has certainly evolved, but, you know, that stepwise progression I gave you, when I just really look and said, that spur is really affecting the patella tracking. I have a lot of confidence now with this approach that I can get rid of it. And I can get rid of it, it's going to heal. I'm going to like the anatomy when I'm done. It's going to look and feel right for that patella and fix the MPFL. And I guess I've got confident with that, but I think we all run the risk of, you know, it must be a nail if I've got a hammer. And I think that's John Fulkerson's healthy comment to us all is let's not be too aggressive with it yet, because it's certainly more risky in the sense that you're doing a lot of work underneath your articular surface and if things go wrong and they're 14 years old, you got a real problem. Then you're talking about a full-time secundal allograft. Yeah, Dave, this is Dave Latul. Great talk. And I agree with everything that you said about this. You know, without a doubt, this is a real surgery. I think the important thing in terms of learning curve, you got to make initially, you know, big incisions. You got to see things. I am a thin flap guy. You know, I saw David do this and I've seen, David DeJure do this and I've seen you do this with the thicker flap technique. And it's a tough technique, without a doubt. I think the thin flap, I can do a lot better, you know, sort of contouring things, not better than you, but just in my hands, contouring things and, you know, sort of making a groove underneath in the distal femur also. But, you know, it is a real surgery. Fixation is important. I've had to go back on one or two early on when I was going very slow with the rehabilitation for stiffness and they look great when you go back in. And so I think if you are seeing these complex instability patients, I think this has to be a part of your practice. And someone asked a question, how many surgeons across the US are doing it? To be honest, I think there's more and more. I've only been on the bandwagon for about two years. Obviously, Dave Dedick's been doing this for a lot longer than that. And I can't say I've done it in any patients and they've been unhappy, you know? And again, I agree that initially I did it in my revision cases where you don't really have much else to lose. And I think it works out well. So Dave, that was one of the questions. What is, how many people do you think in this country are doing trochleoplasties? Estimate 25. I don't know, what do you guys think? I think it might even be a little less than that, or at least with any regularity, but. I think our fellows now do it, so. But with regularity, that's another matter. Yeah. Well, it shouldn't- I will say that basically I use all the same instrumentation that Dave uses. The only difference is I'm not taking an osteotome to the cartilage. All right, the last couple of questions because we're getting on time. So Jonathan Che from Duke, great talk. Can you comment on how you balance the patella morphology and potential incongruity with the trochleoplasty? And I tried to address that earlier on, but it really is a non-issue, believe it or not. And that is because the, you're taking the congruity that's naturally there, inflection, and just carrying that proximally. So the patella still articulates with that same shape as you carry approximately. This was the same knee, remember? So this is awful in extension. I'm just trying to make this look like this. Okay. Thanks. Last, another question here. Have you had any cases with cartilage defects on the patella and or both trochlea that has changed your intraoperative management? So you went in with the thought of doing the trochleoplasty and then quit. I've had some that were borderline going in. I was worried about too much arthrosis. I scope them first and I have bailed two or three times at least, maybe more. And just too arthritic. I know if it's ebernated bone, especially up on the lateral side where you need it to bend and be reshaped, forget it. It's too sclerotic, it's not gonna work. So I've bailed in those cases. Okay. If there are no other questions, I think we're on time. There was one that Volker had that had to do with osteotomy. So I thought we'd maybe save that for tomorrow and we can talk about the osteotomy tips and tricks after Seth educates us all. So, but I wanna thank again, thank Dave for a phenomenal talk and everybody for contributing their thoughts and questions. And I think this was just outstanding. So congratulations, Dave. Thank you. And you get to hold your national championship trophy for another year. Thank you. Good night, guys. All right. Thanks everybody. All right.
Video Summary
In this video summary, Dr. Dave Dedek discusses trochleoplasty and its role in managing patellar instability. He explains that trochleoplasty involves deepening the trochlear groove to improve patellar tracking and stability. Dr. Dedek emphasizes the importance of proper patient selection and outlines the criteria he uses to determine if a patient is a good candidate for trochleoplasty. This includes assessing the presence of trochlear dysplasia, measuring the height of the supertrochlear spur, and evaluating the patella trochlear index. He also discusses other anatomical risk factors, such as patella alta and genu valgum, and their impact on patellar instability. Dr. Dedek explains his surgical technique for performing trochleoplasty, which involves creating a cavity underneath the trochlear spur and then dropping it down to align with the anterior femoral cortex. He also discusses post-operative rehabilitation and patient outcomes. Overall, Dr. Dedek highlights the importance of understanding trochleoplasty as a treatment option for patients with patellar instability and the need for careful patient selection to achieve optimal results.
Asset Subtitle
April 14, 2020
Keywords
trochleoplasty
patellar instability
trochlear groove
patellar tracking
stability
patient selection
trochlear dysplasia
supertrochlear spur
patella trochlear index
anatomical risk factors
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