Hello, everyone. First off, my disclosures. They are on the Academy website, but specific to this talk, I do work with companies in the cartridge repair world, mainly Veracell, the maker of Macy, and JRF, and Osteochondral and Meniscal Allograft Tissue Bank. Let's get started. So my name is Andreas Gamal. I work at the Hospital for Special Surgery in New York, and I will talk about the association of osteochondral defects, cartilage repair, and patella-femoral instability. So first off, cartilage damage is very common in patella instability, especially with recurrent patella instability, RPI. So more than 90% of patella dislocations result in some form of cartilage damage. Now, it might just be a little bit of fissuring, so there's a whole spectrum, but osteochondral fracture happens at up to 40%, and really only a minority of. So in this case, one in four is detected on plain x-ray. So my threshold of getting MRI scans for patients with patella dislocation is very low. So our thinking has changed quite a bit where it used to be, hey, you have a patella dislocation, fine, it's always conservative management first. Oftentimes, we wouldn't even see these patients that would go to the ER, they would be reduced, and then it would sort of go away. And now, I would like to see these patients, and depending on the level of energy, certainly any direct hits, direct trauma, that's something where I virtually always get an MRI scan. If it's someone who's very ligamentously lax, and it was a low-energy trauma with just turning to the side, I know maybe less need for getting an MRI scan because there's less likely trauma, but then again, these patients are also exactly the ones that will go on to having multiple dislocations. So in that case, I even start the workup then and there. The decision-making process for these patients really has dual goals. One is trying to prevent recurrent patella instability, and also joint preservation in terms of looking at the cartilage defect and deciding whether that needs to be fixed. So as mentioned, certainly for me and my colleagues, there's a very strong trend towards getting MRI scans, even for first-time dislocators. Both to rule out loose bodies, and as mentioned, MRI is much better at that than x-rays, but also to estimate the risk of recarts. And why does that matter? And my wife and I have five kids. Four of them are girls. They're all teenagers. And not that any of them had any patella dislocations, and I probably just jinxed that, but if one of my girls or my boy had a patella dislocation, I would like to know what is the risk of having another one, because it's not fun. It causes damage. It does take them out of sport. So if somebody told me, hey, I'm looking at your MRI scan and your x-ray, you are young, your growth plates are open, you have patella alta, you have trochlear dysplasia, you have a Baton score of seven, your risk of recurrence might be 60% or higher than that. I might say, you know what? I'm not waiting for the second dislocation. I will fix this now. And that's against the old gospel that first-time dislocations are never treated surgically, but I would compare that with an ACL. So you have your patella dislocation, you have your tibiofemoral subluxation, your pivot shift, and you tear your MPFL, you tear your ACL. I would not tell a 17-year-old patient with an ACL tear that we should rehab them and wait until they have their second pivot shift, because I worry about their meniscus getting damaged. And with the patella dislocation, I would worry about their cartilage getting damaged. So I've become more aggressive in looking at risk factors, trying to estimate their recurrence, and Aaron Kritsch and a few others have done a great job in looking at risk factors and trying to predict recurrence. It's a much easier decision for surgery if there are loose bodies, because then for the longest time, we've said, well, we need to do surgery at least to get those loose bodies out. So when I look at this cartilage damage, there are a few options. There's removal. So if you have a loose body, you can just take it out. If it's a large loose body, you can repair it. And if it's a large defect but the loose body is really totally beaten up, then you could reconstruct it. So those are our cartilage repair options. So removal. I think overall, when we look at these, we should try and repair whatever we can repair and then everything else we remove. So which defects do we not worry about? If I have a defect outside the direct weight-bearing zone, and those might be very anterior defects on the lateral femoral condyle, as you can see on that MRI scan, third from the left. It's a satural image. The lateral compartment, you see right over the anterior horn of the lateral meniscus, you see this compression fracture. You see edema. This is very similar to what we see in terms of kissing contusion from a, let's say, ACL pivot-shift phenomenon. And are they covered with cartilage? Yes. But are they in a direct weight-bearing zone? No. In fact, that's an area where we sometimes take oats grafts from. So this is not something I get very excited about, even though technically this is cartilage damage. If something is in the inframedial patella, so also outside the direct weight-bearing zone, the most inframedial patella doesn't really participate much in weight-bearing, so those I ignore. But which ones do I worry about? If you see that open surgical image of a patella that's totally beaten up, this is a defect that crosses and affects the median ridge, that's something that needs treatment. That's not something I would ignore, not in young patients. I think anyone who thinks this will just go away is a little overly optimistic. And in terms of repair, so that's very similar to our decision-making process when we see OCD lesions. So if I have a large piece, if it has intact cartilage, and ideally it has bone on it, except if it's a really young patient that has open growth plates, we can try putting even cartilage-only fragments back on. So Peter Fabrikant here from HSS has written a small study, but young patients with cartilage-only defects, pretty big five square centimeters, they were secured with resorbable darts, and they only had one reoperation after repeat trauma. So it shows it can work. It's not something I would do in a 30-year-old, but open growth plates, if the cartilage looks reasonable, I think this is something we can consider. This is an example from Jack Farr, my good friend from Indianapolis. This is a 16-year-old, still has open growth plates, first time dislocation, really punched off a large piece on the lateral femoral condyle. This is a piece you can see on the x-ray. It has a little bone on it. It's just an eggshell, but three by two centimeters is a little bit too big to just ignore. The cartilage looked intact, and so this was a suture-based repair with drilling into the defect using resorbable sutures and putting this together very nicely, and this healed, and the patient did really well, as you can see on this follow-up MRI scan. This is one of my patients, a young female who had her third dislocation, and on the MRI scan you can see her patella is laterally subluxed. This was a defect that affected the medial facet but went into the median ridge, so not something that I would would ignore and just debride. On x-ray, nothing could be seen. It's just another supporting case to do MRI scans. Two by 2.5 centimeters is pretty large, five square centimeters. The cartilage is mostly intact, some fissures, and this was a repair with a mixture of darts and suture, and she also healed, but there's certainly some that don't. Now, reconstruct if you need to. So, defects in the weight-bearing zone. Here you see this very large defect in a young patient with closing but not completely closed growth plates in the lateral femoral condyle directly in the weight-bearing zone. You see the fragment sitting just in the anterior aspect of the defect over the anterior horn of the lateral meniscus, and again, this is not something that you should ignore. The one on the right, that's a very large patella defect after multiple dislocations. There's even a little bit of an osteophyte in this patient in her early 20s already. Again, it affects the inferior patella, starts at median ridge, and it's too large to ignore. And for that, you just follow the cartilage treatment algorithm. This is the treatment algorithm for cartilage defects, and everyone's algorithm is a little bit different, but this is at least what's on the market. So, we can debride things. We talked about the removal. I put microfracture here. I have microfracture plus because there are certain augmented microfracture procedures where we add things to try and improve on the, at least in the patella, somewhat mediocre results of microfracture. So, I personally don't use microfracture or drilling in the patella at all because I don't think it works well enough to put patients through the still-required rehab that's not any different than the rehab from AC. Osteocondylar autograft, that sometimes works. In my hands, at least, that's a treatment for smaller defects. And unfortunately, based on just the referral patterns, I don't see that many small defects. So, I wish I could use more, but I don't. I do use a fair amount of osteocondylar allografts. Not my first choice in the patella. Sometimes that's the best option, but the anatomy in the patella is quite complex. Everyone's patella is a little different. And to get that match just right, it shouldn't be your first osteocondylar allograft. Let's put it this way. Particular juvenile allograft cartilage is something that has really come in over the last 10 to 15 years. There are no randomized trials, but there are large case series that support its use. This perforated allograft cartilage, that's a more recent entry in the cartilage repair market without much data. And then MACE has by far the strongest support. So, I'm harping on this, but I would say overall, there's a general recommendation against the use of a microfracture in the patella. It's technically difficult to do a good job. Many of the dislocation-type cartilage defect in the patella are not contained, so you don't have any shoulders. Getting the perpendicularity is difficult. So, using awls in the patella is hard. You just end up digging trenches rather than making nice round holes. But using angled drill bits can help you. But again, it's hard bone. The patella is a sesamoid, so there's not that much blood supply and bone marrow to begin with. And as I had mentioned, it really doesn't seem to work all that great in the patella. And I don't want to be the one who's always a downer on patella and holds up these complex cartilage reconstruction techniques. But I've revised too many of them to believe in it. So, microfracture plus, hoping to juice this up. There are concerns over tissue quality with regular microfracture, so fiber cartilage repair. So, we're trying to augment this, stabilize the clot mechanically with either a solid scaffold like a collagen membrane or a paste to hopefully provide a more favorable environment for cell differentiation. There's some evidence in horses that it works, but there's one RCT of AMIC. So doing a microfracture and then adding a collagen membrane, which in the U.S. is off-label. In Europe, that's a pretty standard treatment. And the AMIC results were sustained at five years while microfracture deteriorated after two years, further supporting not doing microfracture alone in the patella. But luckily we have treatment options that extend past that in the U.S. Many parts of the world don't, and they might have to do this. We don't. Osteocondyl autograft, already said, it's a reasonable option for the smaller defects. If you do multiple defects, it becomes a little bit robbing Peter to pay Paul. You start getting into donor site morbidity. And since we mostly take grafts from the trochlea and then you put it in the patella, at least I would try and avoid the same side of the PFJ. So if you have medial patella defect, take it from the normal side in the lateral trochlea. If you have a lateral defect, think about going to the medial side, but the medial trochlea facet is not very large. So you run out of room very quickly. It also has different cartilage thicknesses because the patella cartilage is very thick. Trochlea cartilage is very thick only in the middle, and we wouldn't take a donor graft from the center of the trochlea. And it's really hard bone in the patella. So don't even try and use a trephine. It's hard bone. You can't really hold the patella still enough. Your angle will be all over the place. So use a drill, ideally a disposable drill bit, a reamer, like a low-profile reamer, and that works pretty well. Just make sure you keep your bone cool. Again, the patella doesn't have much blood supply. You don't want to cook it. Hangudi, who's the sort of granddaddy of Oates, had good results on the condyles. They were pretty decent, the patella femoral joint, but not as good. And then Shane Ngo and Riley Williams from HSS had a pretty large study looking at Dr. Williams' outcomes, and they were pretty good. And the MRIs showed good fill. Also going to the allograft, I already mentioned that technically it's really the most challenging location, I would say, in the patella. You need to find matching anatomy. Everyone's a little different. And since, unless you treat something confined to the lateral facet, which is essentially flat, you really only have one shot. So median ridge, you have the convexity, so you can't just rotate the plug or it won't fit. So you really only have one shot. And if you do a cross-cut of the patella, so true patella resurfacing, similar to a total knee patella cut, then you have to make a decision. Do you risk overstuffing the patella? By having a thicker residual host patella, because you don't want to get a patella fracture, and you need to have a certain minimum thickness of the donor patella, so you overstuff versus trying to make your host patella remnant thinner, but then as mentioned, you run into the fracture risk. If you look at isolated trochlear OCAs, they have great survival. If you look at isolated patella OCAs, they have decent survival. And then combined bipolar ones are still okay, but a little bit more challenging. So I do patella OCAs not too infrequently if I find that the bone is so abnormal that I wouldn't trust cell-based therapy, but it's not my go-to. Particularly juvenile allograft cartilage, which is a little bit of a mouthful PJAG is a little bit easier. It still has somewhat limited data, but certainly evolving. I do use that in my practice for the small to medium well-contained defects like the one you see at the bottom right. Insurance approval, I said challenging insurance approval. That's a little bit of a euphemism because most insurance policies just say it's not covered. It's experimental, we don't have any randomized data, and if you want to use it, you can. You can bill for a chondroplasty, but you can't bill for this. And some hospitals are willing to eat the cost, but it's not super cheap. And especially if you do it in a surgery center or sooner or later, somebody's gonna knock on your door and ask you to please stop doing that. There is temptation to bill this under the osteocondyloallograft code. That's not okay. This is not an osteocondyloallograft. And recently there have been attempts to sort of ship this together with like cancellous allograft chips to make it cartilage and bone. It's still not an osteocondyloallograft. And I wouldn't, this is not against the product, it's just I wish the company would just get this on the medical policies so that we can get it approved and paid for. If you look at the data, multiple authors over the years, including two from HSS, the bottom two, that showed it works reasonably well. So I think it's an okay treatment option. Perforated allograft cartilage, as mentioned, it's a new entry. This actually is technically an osteocondyloallograft because there's a microscopic layer of bone at the bottom of this. And then it's perforated both to make it flexible, which lends itself to the, as mentioned, complex anatomy of the patella femoral joint, but also to increase the surface area for chondrocytes to grow out and sort of fill and attach. And also for fibrous tissue from the base, which needs to be microfactured or abraded to grow into just to get mechanical stability. It's sturdy tissue, so there might be faster rehab than if you go with something cell-based. But also insurance companies named this product and it has a sister product by name and say this is experimental, investigational and not covered. So again, challenging and it's not super cheap. Matrix autologous chondrocyte implantation, MACI, that's been around the block for a long time. The predecessor ACI and MACI together, this worldwide data, it goes back over 20 years. And yes, I do consult for the company, but I also consult for an osteochondral allograft company. So I think I'm equally conflicted in both directions. This has the most data. It's not to say that I fix every defect with that. In fact, I use more allograft than MACI, but that's because I treat more chondral lesions than patella lesions. It is now indicated anywhere in the knee, including the patella, including the tibial plateau. And that was updated with the FDA approval of MACI versus the predecessor that was not indicated in the patella and luckily most insurance companies have updated the policies and now allow this in the patella. A lot of studies, including one that I did with my colleagues and friends at Rush and OrthoIndy and the Brigham, and we had a total of 110 patients with minimum follow-up of four years and 92% of patients were happy. And interestingly enough, there was no significant difference between uni and bipolar lesions. So I would say in the patella femoral joint, this wasn't isolated to instability patients, but at least in the patella femoral joint, bipolar does not necessarily equal arthritis, don't touch it with cartilage repair, more so in the tibiofemoral joint. The third study from Zarkaitis is actually very impressive because this is army personnel. So they are all almost professional athletes. They had a good four and a half year follow-up. They only had three failures and 78% returned to their occupational specialties. Now there might be mechanics and electronic specialists, but they all have physical requirements and the army washes out people pretty quickly if they can't perform. So this I think is a very impressive study showing that this can work. This is a case of a reconstruction. This is a young girl, she's 12. She had 10 plus dislocations. Not sure why anyone would allow that poor girl to go through this and just kept watching. And she developed a lateral femoral condyle defect. And if you look at the second MRI image, the sagittal one, second from the left, if you look closely, it's not just one defect, it's really a succession of defects where with different dislocations and different flexion angles, she knocked out different pieces of her lateral femoral condyle. And it was four and a half centimeters long, two and a half centimeters wide. It was almost her entire lateral femoral condyle. And she was in valgus. There was nothing to repair. Luckily, her growth plates were still open. So I did this case together with Dan Green, my pediatric orthopedic surgeon colleague and friend here at HSS. And he did a hemi-epiphysiodesis guided growth where he stopped growth temporarily on the medial condyle and let herself grow out of valgus. That's much more desirable than waiting and doing a distal femoral osteotomy. And then at the same time, we did a MACE, we did an MPFL reconstruction. And she's now, let's say about two years out and she's not perfect, but perfect with this kind of knee is elusive, but she's very good and certainly much, much better than before. And most importantly, she hasn't had a single recurrent dislocation since. This is another case of a dislocation. This is a 20 year old male who had two dislocations and he had a loose body removal after the first dislocation, nothing else was done. And then he had a second dislocation and now he has persistent pain. And he had a 20 millimeter osteochronal allograft for his medial faceted median ridge patella defect together with an MPFL reconstruction. Why did I go with an OCA in this case? His bone was really beaten up, as you can see in the before axial image on the left. And then in the after image, it has a good contour and restoration and he had the MPFL reconstruction. He's a couple of years out as well, no recurrent dislocations and his pain is gone. So how do we choose our treatment options? Well, one thing is we look at the subchondral bone and that helps decide between a surface, cell-based procedure, if the bone is intact or mostly intact, so MACI or PJAC. If the bone is really compromised, then we would go more with an osteochronal procedure like an OATS or an OCA plug. And then we also look at size. So if it's something small, we can get away with OATS or PJAC. If it's medium, MACI, PJAC, maybe the perforated cartilage grafts. And if it's a large defect, that's MACI or OCA. So in summary, small defects in the inframedial patella and the most antilateral femoral condyle, those generally can ignore, you remove the piece, but don't forget about treating your instability. If you have a larger fragment, if you can repair it, try everything to repair it. Even if it's a cartilage-only fragment, in young patients with open growth plates, you can try that and they have a decent chance of healing. After a growth plate closure, I would not do that, unless it has good bone on it. Irreparable larger defects, those who really should reconstruct, and both MACI and OCA have a long track record. OCA can be a little challenging just based on the technique. So if you have a lot of osteocondylar allografts under your belt, by all means, tackle the patella. But like I said, it shouldn't be your first or your 10th even. And then PJAC and perforated allograft, they're potential almost off the shelf options. But as mentioned, insurance approval is, there's no such thing as approval because they are excluded in the policies. You can try peer-to-peer reviews where you try and explain why you think this particular patient needs that, and they might approve that as an unlisted code, but that's definitely a case by case decision. And with that, I thank you very much for listening. I hope this was helpful. And if you have questions, email me. My email address is in the middle. And a little shout out to my kids, at least two of the five, and my beautiful wife and colleague at HSS, Sabrina Strickland. Take care. Bye-bye.

cartilage repair

patella-femoral instability

MRI scans

recurrence risk

treatment need

individualized approach