Good morning, so hopefully this is last but not least. And I think one of the things to really think about is that if you address some of these problems earlier, and maybe you don't get to the stage where you actually need cartilage surgery. So a lot of these lesions don't necessarily need surgery. And so this is basically, hopefully we'll talk about what lesions actually need surgery and what to do about it. And cartilage loss is often hard to predict from X-ray. And so in most cases, we get an MRI for every one of our patellar instability patients or patients with significant patellofemoral pain. And here you can see the X-ray merchant view looks perfect and a significant flap in cartilage loss on the medial facet. Most importantly, not everyone with pathology needs surgery. So this woman on the right ran the New York City Marathon just six months before I saw her. So despite the fact that the MRI looks terrible, I don't think she would have responded very well if I told her she needed an arthroplasty at that first visit. That being said, you can't let that patella get too thin because you do need some bone stock if you're going to have the most extreme of cartilage surgery, which is a patellofemoral replacement. So why do these patients get cartilage injury? Well, clearly a trauma such as a patellar fracture, but also a patellar tendon tear. I've seen a number of these. You can see this image where they failed in continuity with significant patella alta. And so this needs to be addressed both to put the patella where it should be as well as treat the cartilage. Obviously from dislocation, you can see essentially the entire medial facet has been sheared off in this young patient. And cartilage injury is very common after dislocation. In this study, they had 28 osteochondral fractures in just 39 patients. And so we certainly don't wanna leave these patients with recurrent instability. Malaligned patients, when you see an x-ray like this, I can almost guarantee that if this has been going on for a long time, they're gonna have some degree of cartilage injury. The image on the upper right, it's complete lateral trochlear cartilage loss as well as lateral facet of the patella. This patient was 30. So clearly not a candidate in my opinion for metal and plastic. And then bad surgery. So unfortunately I see this all the time. I have a large referral patellofemoral practice. And so MPFLs are not, it's not a benign surgery. It's not that easy to do. And it's not uncommon to get those anchors in the lateral facet. And then you have not only a recurrent instability problem most of the time, but you have a significant cartilage problem that affects the bone. So why do you wanna fix it? Is one of the reasons to fix this besides the patient has come in quite unhappy is that it does lead to generalized knee osteoarthritis. And the patellofemoral instability symptoms are not necessarily related to the degree of deterioration. There's just a couple studies showing less progression of arthritis on MRI, but there are some. And so what's the treatment algorithm? Well, in some cases you can just debride them or just unload them. And I think if it's a small lesion, I think that's reasonable. And then repair, in my practice, microfracture is really not an option. An osteochondral autograft, I'm gonna get to this, but pretty rare that I do that in my practice. I hate taking a plug from the trochlea and putting it on the patella. If you look at studies, and I don't expect you to read this, but this is back from 2008. There's just not a lot of data on patella cartilage repair. There's very few studies, there are few and far between. So removal, so when do you just take the fragment out? If it's a small fragment, it's a non-weight-bearing area, you can see this MRI where it's a lateral femoral condyle defect, but it's quite anterior. It's not really in the weight-bearing zone. Inferior medial patella, I think those lesions can be ignored. But ideally, you repair it, especially if it's a skeletally immature individual. If it's a large piece with intact cartilage, especially if there's bone on the back of the defect. Peter Fabrikant, who's a pediatric orthopedic surgeon at our hospital, had 15 patients. They were all young, with an average age of 12.7, with cartilage-only defects, but pretty large, almost five square centimeters. He secured them with smart nails, which is one type of resorbable dart, and only one patient had a re-operation after repeat trauma, so actually very good results, especially in young patients. I said I don't particularly like mosaicplasty for these patients. Two studies, one had 74% good results in the patella. A study out of HSS was 71% with flush-plug appearance. The patella bone is really hard. I use the analogy, if you're Tyler, Tyler of your bathroom, and 71% of the tiles were flush, you wouldn't be very happy. I don't think the patella's particularly happy. On this bottom image, though, if it's a small defect with a lot of bone edema, and the patient's very symptomatic, I think sometimes an autograft is good for these very small lesions that are very symptomatic, again, with a lot of bone edema. What about Cartiform? It's perforated allograft cartilage. I have no experience with it. There's no data. What the company says is that you're potentially combining the effects of OCA and cell-based treatment. It's malleable, it's sturdy tissue, but again, I don't really think it's a great option. One of my former fellows sent me this image because he thought he was gonna get in there and be able to repair the cartilage fragments, and he couldn't, and the only thing they had on the shelf was Cartiform, so I think situations like this are reasonable, and you can take a biopsy and go back later, especially if you haven't violated the bone. But the issues were, this is cost. You need an anchor to somehow tack this down, and then now you have bony issues, and the rehab is still slow. So as a general way of looking at this, if the bone is normal, I think you should look at cell-based particulate cartilage or MACI. If the bone's abnormal, I typically use an osteochondral allograft. Here's another image where the anchors violated the cartilage, and if there's significant bone involvement, you need either a shell allograft or a massive graft, and this should be quite rare. What about juvenile particulated cartilage? The problem is is that insurance doesn't pay for it. The only time I've heard that insurance pays for it, and this is what my billing company tells me, is if I say it's an osteochondral allograft. I don't need to go to jail. I don't wanna have insurance fraud. I don't bill for an osteochondral allograft when it's just chondral, but there are a number of studies. Brian Grawe looked up our patients, and we had excellent fill-in MRI at one year at 85%. Mark Tompkins had 73% back to normal or nearly normal function. Jack Farr had a Q score of 84. Pretty good, 17 patients, but these are all pretty small studies, and unfortunately, insurance still does not cover this. As far as what I spoke about before, like sometimes you can repair it. Here's the fragment. Here's an image where I only could get part of the fragment back, so I did a hybrid repair. Luckily, we do have particulated cartilage on the shelf, so I basically just pretend I didn't do it, so I just billed for a repair, and I stuck this particulated cartilage in the defect that was residual. I think this is a good option. If you have this on the shelf, even if you can get some of it back, I think this is a good option, and what else is the problem with this, and why does a lot of hospitals not let you use it? It's $5,500 a packet. The fiber and glue's another $500, and we don't have long-term data. We pretty much lock the brace and extension and let them wait there, and we use a CPM for these patients. What about Macy? Well, Macy's great, except it takes two surgeries, and so again, you want to contain defect. It's $55,000. Medicaid doesn't cover it, and sometimes it does take a little while to get insurance to approve it. In the last year and a half, we finally got UnitedHealthcare to approve this on the patella, and as you can see, I did this through two small incisions. You can see the osteotomy distally with the cartilage repair approximately. I'm in the process of doing a multi-center study. I've got 145 patella patients. 50% of them did have a concurrent osteotomy, and 70% of them were female. Next year, I'll be able to tell you how the outcome is because it's taken us a while to get this data out of multiple institutions, but there is good long-term data, 2014, 2013, with very good data on the patella. Here, just a number of other studies, but essentially, the one thing I can tell patients with Macy is there's good long-term data for the patella. Again, slow rehab, and the old way that we kind of did this, and I still do this all the time, is I just put the Macy membrane on a Tegaderm just as it gives me a stiff surface so I can cut it, but most of the time in this patient, you can barely see it on this video, but it had a large cartilage flap. For this one, I used the cookie cutters, which makes the surgery so, so easy. You can see I'm kind of scooping out the flap with the cookie cutter in place, and then finishing off, evening out the cartilage resection, and here, you can just cut it, it takes two minutes, but you can't always do that, depending on what the shape of the lesion is, and lastly, what about osteochondral allografts? Well, Bill Bugbee's done pretty much all the studies looking at results of osteochondral allograft. He had 27 patients, and 89% of them were satisfied, or extremely satisfied. I think these are technically difficult. It's really hard for me to get female patellas, because I try to sex match all my osteochondral allografts. I do about 40 osteochondral allografts a year, and 30 of them are patella, and I would say that it's a great option, but I always start with cell-based if I can, if the bone is good quality. This patient actually had a bipolar allograft. She was the 30-year-old I showed at the very beginning, large plug on her patella, large plug on her lateral trochlea. Again, I like it to be sex matched. It's $11,000 per graft, so $22,000 for this 30-year-old female, but she's quite happy. She's now walking her dog in New York City. That's a lot of my patients' goal by the time they see me, is just walking without pain. The rehab's a little bit easier. We do lock them in extension for four weeks, but we don't use a CPM. And lastly, a PFJ. This is bipolar disease. Typically, I want the patient to be over 40, but my average age is 53. Failed cartilage repair, failed TTO. Most of these patients had previous surgery, but as I mentioned at the very beginning, you have to watch these patients and make sure their lateral patella doesn't get too thin, because otherwise, there's very little to work with, and it's one of those times where you just don't want to wait too long. Sorry, this seems to... In just a minute, you can see, again, I use a very small incision for my PFJs. I take about 25 minutes. My patients go home the same day. We don't use nerve blocks, but we do do... You can see this is a very thin lateral trochlea. She's essentially acetabularized it. We use a periarticular block. I like this patella. I actually hate this patellar reamer, but I think it's really effective for these patients. I hate it because I still have to even things out at the end, but because the bone is so sclerotic, I think it's a good way to prepare the patella, but you're essentially doing the same thing you do in a total knee. There's different brands of patella femoral replacement out there. Most of my experience has been with one unless the patient's allergic to nickel. I do mark white sides line, or at least where I want white sides line to be with two parallel lines, which allows me to see through the anterior cutting guide and adjust my rotation. The thing I like about this system versus the robotic system is that it's really easy to change your external rotation. You just kind of are looking down and adjusting at this step and adjusting your anterior cut. Essentially, once you make the anterior cut, you're almost done. Here's a reaming guide, and that's reaming out the trochlea. You really want just a smooth transition. Here's the reamer reaming out the trochlea, and then I basically trial it, and I'm done somehow. I think we'll stop if we don't have more. I want to make sure we have enough time for questions. I have some cases if you want. Yeah, we can always talk about these if you want. Yeah, that's great. Awesome. As we're coming up, I have a question. Clearly, Sabrina has extraordinary experience with cartilage reamers in the tele. Just the numbers she threw out there casually, 140 Macy's and. So for many patients with history of patellar instability, a lot of them just have inferior medial cartilage loss. And so I think those you can ignore. If you see a lateral maltracker who's also dislocating, you're almost dealing with two different problems. You're dealing with the instability that potentially injures the lateral femoral condyle or the medial facet, and then you're dealing with the fact that they've been maltrackers. And so I think a lot of them will do just fine with an osteotomy if it's a lateral cartilage lesion. But once that lesion gets to be above a centimeter and you can unload it, I think adding something at the same time is a good idea. So to answer your question, generally insurance wants you to have bigger than a 15 millimeter defect. I think most of the time, the defects I'm fixing are over a 15 by 15 millimeter defect, and I certainly try to unload them if I can at the same time. Anybody prefer CT? Get CT? MRI is your go-to? Yeah. Radiation concerns? Kids? And the location of the patellar tendon insertion, I think, matters just as much, if not more, than the actual location of the bone. Sometimes you'll see on the MRI the patellar tendon, that very distal aspect of the patellar tendon, looks a little bit more lateral than the center of the bone itself. So I think it might reflect more accurately what's going on. So you're measuring the center of the tendon, not the highest point on the tubercle. Correct. Which is an important takeaway for the TTTG. So not the tallest point, because that may be the medial part of the tendon, but really the center of where the tendon inserts. And the more abnormally lateral it is, the more that's important to recognize. So at least what I do is when I'm looking on MRI, I scroll down to the right where the patellar tendon is coming off, and so I either use that cut or one cut distal. And so I think that's really important, because I don't really care where the distal part of the patellar tendon is attaching. I would say bioreaware, because I think we're learning more about it. Medialization of the trochlea, the rotation between the tibia and femur, and the lateralization of the tibial tubercle. Those are the three factors. And I think the TTTG is overused. And I think if you bend your knee up and your tubercle sulcus angle, if your tubercle is directly underneath the center of your knee at 90 degrees, and you move it medial, you're putting increased medial forces. This is medial. Increased medial forces on not only the medial patella, but the medial tibial femoral joint. And so I think we just have to take that TTTG measurement with a huge grain of salt. And I very rarely use that particular measurement in my decision making. Interoperatively, I use the tubercle sulcus angle. When I'm moving it distally, I'll line up my tibial tubercle to be underneath the center of the femur at 90 degrees. And that's how much I medialize it. And I'd also say make sure you check for yourself. It's tempting to look at a radiologist's number on your report, but look at that. Take a couple extra minutes and take a look at it and do your own measurement, and you'll be amazed. Even at a center where we do tons and tons of this, and I do research with my radiologist, the numbers are still very frequent. I'm always on the phone saying, hey, can you please reread this and modify the report? Because go back and look. And typically it's because the fellow ended up doing it or somebody who's not normally doing the measurement. But don't just believe it. Check it for yourself. And the trajectory of the patellar tendons, I think, Dave, you showed that. PTLTR, yeah. Yeah, the PTLTR is the sort of the lie of the patellar tendon over the lateral femoral condyle. Sometimes you have a TTTG that's kind of shockingly high, you know, 1720, and your patellar tendon is centered. If you put those two variables together, I think it's very helpful. And just the opposite. You can have a normal TTTG with a very high PTLTR, and that's telling you a lot about a bad vector that you've got to take into account. Mistovich, AJSM, 2020. Very good paper. Yeah. I'm sorry. When you decide to do proximal or distal? You know, I think it depends. If you're going to do two-plane osteotomies or if you think you need to correct at the knee level almost all the time, you might do a plate distally. Our center has gotten – it's really surgeon-specific. Our center started doing rods. I was trained under Mark Swientowski, who came, you know, as a big trauma surgeon, so we started doing IM rods. And I think that they are nice because you can avoid the proximal. I mean, when I first started, we did proximal ones because that's what the pediatric hospital did. Then we went to IM rods. But now if you're going to do something at the knee level, we may do it combined with a distal osteotomy. I think it's really just your preference. I don't think there's a better or worse way to do it. That's my opinion. That's all based on, I mean, I do measure the TTTG, but it's really when you start looking at these axial cuts in the MRI, and if the patella is sitting far lateral or significantly lateral and it's a lateral defect, I think you're doing an unloading osteotomy, and I'm always anteriorizing when I'm medializing. I don't think I've done an Elmslie in the last 10 years. I mean, I basically move it anterior medial or I move it distal. And I alter the slope of my osteotomy depending on how much I want to anteriorize it and what the actual numbers are. But you can see it just where the patella wants to sit, and so I think you're looking at that tendon. I don't measure that PTLTR every time. It's just when you start seeing things that don't really make sense that I start measuring it. And I look at where that patellar tendon is crossing the trochlea. Yes? Any thoughts on when to act on internal brace fever and VHL? Never. Yep. Never. I think that's a dangerous move. So the problem with MPFL is it's so easy to over-constrain that joint. So some people would use a cinch suture, like a tightrope or one of the other industry devices to perch it with a button. But if you're going to do that, you have to be willing to go cut it out if it's too tight and it's not something you can loosen without making another incision. And I worry that the internal brace, unless you're, I don't know that you need the strength because everything that we replace the MPFL with is vastly stronger to begin with just in terms of graft. And then I worry about over-constraint. I agree. I mean, by the time you get vascularization, it's usually bigger and thicker than your MPFL. We know that it's stronger. Unfortunately, it's also stiffer. And so I just think that you're going to have revascularization at a rapid rate at the same time. I mean, the internal brace is trying to bridge that revascularization. I don't think you need it. What about this hyperlax patient? Do you trust her collagen? Yeah, but do you trust the internal brace? I mean, eventually, the internal brace changes. And, you know, it is true that with the hyperlax, I'm more likely, I mean, I use Allograft anyway, but it doesn't seem to be so bad because I think that even though we know they replace it with their own collagen eventually, it is thicker and it will eventually be stronger. So I just think that it is a tough patient. And then you combine that with hyperextension at the knee and it becomes even tougher. But I wouldn't use an internal brace. Yeah, I seem to be a magnet for Ehlers-Danlos patients. And I just, yeah, I find myself just more aggressive with the bony realignment. If I can find any excuse to move bones around to help stabilize this thing and track better. And just on that note, just pay attention to the hyperextension because if they have borderline patella alta and then you're not going to measure them on the MRI in hyperextension, but it's going to be more. But I've had, I mean, I don't know how many just isolated NPFLs in patients with normal alignment with Ehlers-Danlos and they've done great. So I wouldn't worry that much. I do always use an Allograft. Right. For us right now, the optimization in our hospital for all patients is if their BMI is over 45, they need to either get under 45 or lose 10 percent of their weight. We have a comprehensive weight management program. You know, you can't succeed with them all, but they have to go to a program and they have to show diligence in making an attempt. And you all know that if you start to lose weight before you do the surgery, the chances of them continuing to lose weight is higher. It's their relationship with food that's altered, and I think you've got to do something. I think you've got to do something, personally. That said, I've run into some patients who just can't get out from under their instability and they keep falling, and so I've gone forward with surgery, but like you see me measuring isometry over the soft tissue envelope, it really disrupts that. You can't really apply that as directly to what's going on underneath that skin and subcutaneous tissue. So it makes everything more difficult. They have more trouble non-weight-bearing if you're doing osteotomy surgery, and so you just have to be hypervigilant and lose more sleep. I do a lateral release in a lot of cases. So a release rather than a lengthening. I think our preferences in general, Sue, you didn't hear anybody talk about lateral release. Notice that? That's the last thing we do in a procedure, and it's not fixing the problem. So it's to fine tune it at the end. I think our preferences do a lateral lengthening, a Z lengthening, and preserve that layered tissue to balance the medial side. But with a fixed dislocation, you don't have enough tissue. That's where I'll use a patch to fill a hole. The other thing is a lot of times you have to take off the vastus lateralis, and you may reattach it more proximally. I think that's necessary in a lot of these fixed cases. I mean, you can kind of pie crust that tendon, but I've generally just taken the lateralis off and reattached it more proximally. You also have to consider a quadplasty. I think most obligate dislocations and flexion, the sooner they dislocate, like if they dislocate at 20 degrees, then you probably need a quadplasty along with it. If you do a quadplasty, the vastus lateralis usually stays with the lateral quad, so just consider that. How do you do that? I do an inverted V-Y. I've done Z lengthening, but right now I do an inverted V-Y. And detach the vastus lateralis. No, but if it's inverted like this, that vastus lateralis stays with that lateral side. I've done both, but then you're kind of dealing with real little pieces, but now I do this. And that's why I do an inverted, so the bottom of the V is at the patella. You can just go around like this, keep the vastus lateralis with the lateral quad. It's hard to go more than 15 to 20 millimeters. You can. It makes everything more difficult. So you do what you just said. You calculate how to get into a normal range and if you end up at a CDI of 1.1, that's okay. It's more normal. Of course, also look at the sagittal engagement and everything else, because the CDI is just a rough approximation. So Andy, what's your biggest that you've done? The greatest amount of distalization, probably two centimeters, 18 millimeters. David? Maybe 14. Sabrina? My target's 1.1 though for CD. Yeah, probably 15. I just got accepted by AGSM, so it's gonna be published soon. I never go more than 15 and sometimes I do leave them at 1.3. And but of the ones that I've done, it was a cohort of 69 patients and most of them were below 10. But then there was 10, 12, 13. It's interesting that you say this because I've been on two panels where they said they never do more than 10. And I know that some of them have done more. You know, I think that you, but I think that once you get up there, and the ones that were 15 millimeters, between 10 and 15, they did not have any higher complications, but as Andy has shown, you'd end up having to watch that distal fragment for a long time. So you really, it takes a long time for that to heal, especially if you go down. Three screws. Three screws are helpful. And then just to follow that up, if you do get those cases of delayed radiographic union, are you delaying the weight bearing a little bit because it's not tender, or are you just, how are you managing that? I don't. Because the radiographic healing always lags behind clinical healing. So examine them clinically, look closely at that anterior cortex. You often see some periosteal healing that's jumping over the end of your shingle. I think if you repair the periosteum, get some soft tissue over the top, I think that's helpful too. The other thing I would say about doing an excessive distalization is I'm sure you're changing your joint reactive forces. Absolutely. So those are the ones I think you have to be more aggressive with soft tissue balancing, lateral releases, and maybe even enterizing osteotomy. Because as you come down the tibia, if you just distalize, I think you posterize. So I think that's where you incorporate a slope into your tuberosity osteotomy so you get an enterizing effect. If you come to our talk later, or my talk later, I do my distalizations a little bit differently, and we just are in the process of looking up all our distalizations as far as that exact question, if we're posterizing them, at least the way we used to do them. So now I do all mine as a chevron, so I enterize every distalization, and I don't have that little line that I have to watch, which has made, I think, the recovery much better, but check back in two years when I publish them. You don't have that line because you're doing this, but then you can't follow it if you're not able to look at it. Great. I'm not worried about anything. It's a larger surface area. Yes, exactly. The problem that I had with the chevron is you're dealing with cortical bone on cortical bone, and that's why I stopped doing it. Either way, I think it's tough. But Andy said it. You gotta watch jumping and pivoting sports. You can't let them go back. And the ones who wanna return to run, I think the ones that you worry about are the ones that get clinically silent, they're feeling great, and then they start to get back to running. I've had kind of a heavy patient start to develop a propagation of that thing posteriorly. So you really don't wanna lose track of these people, and so we backed her off on her weight-bearing. We put her back on crutches for a month. She hated it, but she healed okay. You just don't wanna lose track, and I think this is what made me switch to Dr. Strickland's technique, which is very helpful, I think, for sort of containment. But I guess, yeah, time will tell whether the runners do any better. They're still cutting the cortical tibia, which is. Someone asked about the high BMI patient, and that's a patient I would be much less aggressive with an osteotomy on. In fact, I mean, we've all sort of evolved our own algorithm based on our experiences and our resources. I've evolved away from osteotomies on that high BMI patient, and in those select cases of 50 or more, or somebody, I mean, they tend to be less active, but I'm much more likely to do just an isolated, simple MPFL reconstruction, and that's just been my experience. So, if you have a first-time dislocator that, for any reason, you decide is high risk for recurrence or has a loose body that you're going after, you're going to operate on that. If you see no signal within the ligament itself, you see a pure avulsion, I think it's a reasonable thing to consider repairing, but the rate of failure is so high in the recurrence literature that I tend to default to reconstruction alone. I work next door to it. If I see the fragment, I'll excise it and just put a new tendon as a new ligament there. I don't know how you guys feel about this. I agree. I think the risk is just too high. The tricky thing is if they have those anatomic risk factors, and then suddenly you have a first-time dislocation, you need to get a big, loose body out or repair it, when do you add an osteotomy onto that, and suddenly it's a big operation? That's a tough question. Yes. And they all have anatomic risk factors. A normal knee does not dislocate a patella. We've all got something going on. Right. The question is how much. Right. Yeah. And Bob Magnuson puts it well. Is it just one more instability episode, and then you're distalizing it for it's all time? It's not really, are we going to make this decision and leave them with what they've got? I think one other benefit is you're putting in something that's stronger than the original part if you're reconstructing, and so if you're trying to overcome these risk factors in a first-timer with something, and you don't want to do an osteotomy, that might be a good middle ground. One more question, because we've run over here. Yeah. Is there a role for MQTFL reconstruction instead of dealing with the body anatomies of the patella in practice? The literature says that the stability of it is a little bit different in early flexions. You want to consider that. But especially in revision situations, if I have a lot of previous holes in the patella, I'm trying to work around it, or if you're, heaven forbid, working around an arthroplasty, or it's getting complicated for any reason, then I think there's a great role for attaching to the distal quad. I think the hybrid construct is really nice. If you can get one fixation point on the patella and then maybe weave it up and over through the quad, that's nice. You have to have a little bit of a longer graft, so like a 24 might not cut it. You want your 26, something like that. But I like having it as an option. The only thing I would say is the injury doesn't go up that high, and so if you're trying to follow the pattern, but I do think that it has given us another way to deal with revisions, to deal with small patellas, to deal with children. I wouldn't do it only, though. I think it's not the right way to do it, but I think a hybrid is a very nice option. Awesome. Thank you, panel. Thank you, guys. Thanks for coming. This was great. I learned a lot. It was wonderful.

cartilage surgery

surgical intervention

MRI scans

cartilage injury

knee osteoarthritis

patellofemoral instability

cartilage repair