Hello, everyone. Let's start with disclosures, and I do have things to disclose. You can find those on the Academy website, but for quick reference, I do work with companies involved in cartilage repair, specifically Varicell, the maker of Macy, but JRF, an osteochondral allograft and meniscus allograft tissue provider. So, my name is Andreas Gomahl. I'm at the Hospital for Special Surgery in New York, and I will talk about failure of cartilage repair. I do a lot of cartilage repair, and unfortunately, if you do a lot of anything with that, come failures. And if anyone tells you that they don't have failures or they don't have complications, I would say they're either incredibly gifted, they don't really do very much surgery, or maybe they're overly optimistic and don't realize that they do have failures. But I think most of us mere mortals do have failures and complications, and it's always worthwhile knowing what's the plan B if something goes wrong, and how can we revise previous failures, and that's what I'll spend the next few minutes talking about. So, in thinking about how to manage failure, it's helpful first to figure out if this is a failure of a specific repair that you've done in the past, or if just the knee overall has worn out. So, if you did a repair in the medial compartment and patients come back a few years later, and now they have pain in the lateral compartment, and you get an MRI scan, and your primary repair still looks good, but they've developed a new lesion laterally, I wouldn't necessarily call that a failure of a primary procedure, which is the rest of the knee has progressed, similar to, let's say you do a medial uni, and they come back at some point with lateral compartment wear. But if this is indeed a failure of your previous procedure, then you would want to figure out what went wrong the first time, because if you can't really figure out what went wrong the first time, it makes it a lot more difficult to do a good job with the revision. Now, sometimes it's just random, and we'll talk about this, but it sure would help you do a better job if you could identify some technical issue with the first time, similar to revision ACL surgery. So, we'll discuss how does cartilage repair fail, why does it fail, and then how do we manage failure? So, I said trying to identify the failure mechanism can help avoid failure of the revision, and also, the more you learn about how cartilage repair fails, it also makes you a better primary surgeon, because to a certain extent, you can pre-empt failure by doing the best possible job first time around. So, what are the different ways how cartilage repair fails? Well, one I alluded to is progression of disease. This, on the top right, is a kind photo donation of my former partner at the Brigham, Tom Minus. This is a knee joint where he had done ACI to the medial condyle, the lateral condyle, and the trochlea some 15 years prior, and if you look at this, you can identify some areas that have cartilage, and those are actually the former ACI grafts, while everything else around it has really continued to wear down. So, is this failure of the prior ACI? No, it's failure of the rest of the joint. That might be semantics to the patient, but it, I mean, here, this is in stage OA. This is a patient who underwent total knee replacement, and that's the appropriate thing to do, but let's say if this were just one additional cartilage defect, then at least to me, it seems this is a patient that responded quite well, actually, to ACI, and I might pick that again to treat the additional failure. So, at the bottom, you see an example of a patient who had an ACL reconstruction, and he only had a small lateral meniscus debridement. He had a medial femoral condyle cartilage repair at the time of his ACL reconstruction, but then two years later came back with effusions and laterally sided pain, and you can see very significant bipolar progression of disease. Again, not failure of the cartilage repair in the medial compartment, which was doing fine, and it didn't hurt there, but progression of disease in another compartment. So it's a little bit of a different animal than failure of the cartilage repair. So now let's move on to actual failure of the primary repair itself, and delamination is something that can happen with any kind of cartilage repair, and I have two examples here on the right side. So we have the right tissue, but unfortunately it failed either because of repeated trauma or incomplete biologic integration. So on the top right, my first example, this is a MACE procedure in the medial femoral condyle, and you can see it's completely delaminated, but the tissue itself looks good. And I had sent this to the lab, and they came back and said this is a mix with a high percentage of hyaline cartilage, and so happy about the biology, ACI worked for this patient, but then at about a year post-op, she was hiking, she jumped off a rock, and she delaminated this. Bad luck, but this is a delamination, so this is something where I would consider doing another ACI. At the bottom right, this is a little bit of a different story. This is a patient who had an OCA and sort of did okay post-op, but there was never really a time when they were perfect, and then around, I believe this was nine months out, they really had more pain in the previous location, similar symptoms to what they had previously, and effusion, and there was increased signal on the MRI scan, so I took them to the operating room, and if you just look at this, it sort of looks okay on the surface, so the cartilage is intact, but then as you probe it, you can see that it's unstable, and if you play with this, it also delaminated, so this is not so much an acute trauma for this patient, but it's a failure of integration. Biologic failure we see mainly with cell-based therapy, so instead of what we want, meaning cartilage or at least hyaline-like cartilage, we get something else, either bone or just a fibrous scar, so at the top right, this is a patient who had a microfracture, and it looked pretty good on MRI scan, but they had persistent pain, and on arthroscopy, it actually doesn't look so bad, but then when you probe it, you can see how the tissue is completely soft. It doesn't really protect the underlying bone, so this is just the wrong tissue forming, and this was at about six to nine months, so this is not going to get any better with time, but sometimes, instead of fibrous tissue, we get bone, and that you see any time the subcoronal plate is injured, so that can happen with ACI if you are a little overly vigorous in debriding the layer of calcified cartilage and injure the bone where you get all this diffused patechial bleeding. It's pretty more commonly seen and associated with microfracture or drilling where you injure the bone and the bone reacts with a bone healing response, which is callous formation, so at the bottom, you can see a CT arthrogram in a patient who had a previous microfracture, and you can see how the bone formed an intralesional osteophyte that comes to the surface covered with just a very thin layer of fibrous repair tissue, and on the right, this is an intraoperative image where you can see how that looks after debriding the overlying soft tissue. You have this little mountain of bone that sits in the defect. Collapse, that is something almost exclusively reserved for osteocondylar procedures. Sometimes, you see that in autograft. Oh, it's more commonly in osteocondylar allografts. The allografts, the cartilage layer is not really that antigenic. It's the subchondral bone, and the more bone you transplant, the bigger the antigen burden, and Bill Bugbee has done nice studies looking at titers of antitoxic antibodies showing an immune response to the transplanted allograft tissue, and the bigger the graft you transplant, the higher the conversion rate. So at the top right, you see an MRI scan of a patient who had a previous osteocondylar allograft, and there's edema in the graft. There's cysts behind the graft. There's edema around the graft. So all of these things are a little suspicious for failure, and then at the bottom right, you see the arthroscopy images of the same patient. So the graft already looks a little suspicious, but then certainly once you probe it, you can hinge this open, and essentially this is an OCD lesion. So you have some bone on the cartilage. The bone, the autologous bone, grew into the allograft bone, but it didn't finish the process. It never really made it to the most superficial layer, and a superficial layer is the one that's farthest away from the bone, autologous bone and blood supply. So at some point, the body just stops trying, doesn't integrate the bone, and then it's essentially a stress fracture, similar to what happens with an OCD. The most complicated is pain. So we have someone where everything looks good on MRI scan, on an arthroscopy, but they have continued pain. That's really hard to deal with, and if we can't identify a structural reason for pain, we need to resist the temptation to just do something. So now that we know how it fails, so why does it fail? And this is a little bit redundant in part, but is it bad luck? Is it a bad patient, cytoplasm, bad product, bad procedure? All of these we should ask ourselves really so that we can maybe answer the question of can we avoid the same outcome next time? Some of these we can avoid, others might be due to patient selection, which doesn't help that particular patient. If someone is of a certain age, can't really do anything about that. That's just how they are. It just needs to be part of the discussion. But sometimes it's due to the specific procedure, how it was done, what was used, and that we can do better next time. So obviously bad luck. Can't really do much about it. You counsel patients, this is what happened. Try and in a way be more careful next time. Even though that's a stock image of someone falling down the stairs, but this is actually a real case of someone who had a tibial-tubal osteotomy and literally fell down the stairs less than a week post-op and ripped out his screws and ripped off his tibial tubercle, which actually came out of the skin since the incision reopened. Bad luck has nothing to do with by and large how you did it unless you used insufficient hardware. But like I said, this is just something that unfortunately happens. Deal with it and hopefully it doesn't happen again. Sometimes we have a bad patient. What's a bad patient? Someone who has unrealistic expectations. Some just do too much too early and that's the same issue we have with ACL reconstruction where we have mainly young kids who feel good enough at four months to just shoot some hoops with their friends and re-tear early. And this is true for any kind of surgery we do, but we always need to look a little bit at the personality of the patient as well as the knee. And sometimes I look at the knee and say, oh, I know exactly what to do for that. And then I talk a little bit about the patient and say, well, I don't really know how to deal with sort of the things outside the knee and then it's a little bit of an uncomfortable discussion. But I would say the few times where I said, oh, I'll just do it. What could go wrong? I've been burned every time, so be a little shy. And again, this is counseling. Really, I tell patients, especially young patients, before the operation look for the next nine to 12 months. I'll be a downer and I'll slow you down and I apologize, but that's my job to keep you safe. So bad cytoplasm, one part is just look at what you're faced with. So if you have a patient that has an arthroscopy image, like you see here on the top right, that's arthritis. That's not anything by and large we can expect success with cartilage repair procedures, even though somebody valiantly tried to do a microfracture on this. I'm not sure if you can see this on the screen, but if you look closely, you can see a few microfracture holes here and there. I don't think I've ever seen something like this be successful. Smokers, it's a modifiable risk factor and because even though it's hard, but yes, you can stop smoking and cartilage repair procedures are not life and death things that need to happen tomorrow. I really harp on patients to stop smoking and I do test patients, at least for the more complex procedures. I mean, you can say that what you're testing for is to make sure that the byproducts have left your body to make it safe, determine when it's safe. And yes, is this a little big brother in controlling your patients? Yes, 100%, but ultimately if there's a complication, it's on you and no patient will say, well, yes, I had an infection, but that's because I was stupid and stopped smoking, or at least it's a rare patient. Obesity is also modifiable, even more difficult than smoking, but it does compromise procedures and I really, I do send patients for gastric bypass and gastric sleeves. We have a weight management team here for the discussions and they are difficult discussions. and I want to make sure that patients don't hear, hey, you're fat, I don't want to deal with you. I want them to hear, and I literally say that, is help me help you. I really want to help you, and I promise that I will help you as soon as it's safe, and we have a chance that this is successful. And then, you know, age, that's not modifiable, at least not in the right direction, unfortunately. But to me, physiologic age is more important than chronologic age, and sometimes I see 25-year-olds who are very overweight, who smoke, and they might not be a candidate. Well, then I see someone who's 60, and they're in good shape, and the rest of the knee looks good. So I really look more at the joint itself and say, can I fix this, or can't I fix this? And then secondarily, I look at their driver's license in a way to look at chronologic age. I mean, the risk we do run into sometimes is with insurance approval, where of course, the older you are, the more difficult it is for them to approve that. Bad product. There are not that many examples, but enough that it's worthwhile mentioning. So, you know, at the top, there were these artificial plugs, Tru-Fit plugs, famous or infamous. They were initially designed just as a backfill option after harvesting of oats grafts. And for that, they might have been good enough, but surgeons noticed that, hey, what happens? It looks good on the surface. So then people started using that for primary repair. And even though there are conflicting results in the literature, there were a few nice follow-up studies with CT scan, and you can see what that looked like in a patient with a Tru-Fit plug with an MPFL reconstruction. So there's just no bony repair at all. And those were a little challenging to revise. Then there was a decellularized OCA graft that looked green based on the sterilization mechanism, which utilized UV light and methylene blue. So these zombie plugs were enticing because they were off the shelf, and the instrumentation was beautiful. But unfortunately, Jack Farr and I did a study looking at our own outcomes, and we had a 72% failure rate. And even though the company said that was our fault, and we're just not good surgeons, my failure rate with OCA and MACI is far, far less than that, or it probably stopped working. So sometimes there just is bad product. And because of that, even though I like doing studies and testing out new things in a study environment, but I'm more reluctant to introduce things into my everyday clinical practice until I've had a chance to kick the tires in a study environment or had somebody else kick the tires even better. Bad procedure. Now, this is really where we can get into the, hey, this is what we can do better next time. So sometimes we just pick the wrong procedure. So if you have a large defect, six square centimeters, eight square centimeters, and we do a microfracture, that's not just a little bit. That is a Hail Mary, and every study out there has shown that those just fail. They don't work. So I would say don't do it. Sometimes it's not so much the wrong procedure for the specific defect, but we didn't take care of other things. So in the middle image, this is a patient who has a very significant varus deformity. And if you try and just fix her medial femoral condyle defect, I would say that is doomed to fail unless you correct the alignment and do an HTO at the same time. And then last but not least, how we do things, how we handle things. There have been multiple studies that looked at what happens if you hit cartilage really hard, and not surprisingly, it kills chondrocytes, and you need viable chondrocytes for cartilage grafts to be successful. So if you hit an OATS plug or an OCA really hard to make it fit just perfectly, then it might look good at time point zero, but that will break down. So handle them gently, not necessarily with kid gloves, but I put all mine in just with manual pressure, and I very, very rarely use the mallet, and I do feel bad every time I do. So how do we manage failure? Now we need to make our decision, can we do better? If yes, that's the ideal, sometimes we can get to that. But if we figure out how to make things better, so you look at the defect, you look at size, you look at location, you look at the subchondral bone, are there cysts, is there edema, are they contained, are they uncontained, and that gives you the choice of your cartilage procedure, whether that's an osteocondyl allograft, or an ACI, or particulate cartilage allograft. I use a lot of these things in my practice, so I wouldn't say there's one perfect procedure, you just have one procedure that is the best choice for that particular patient. But then also you need to look at everything else, so you need to look at alignment and tracking, the ligaments, meniscal deficiency, to pick what concurrent procedure you do to normalize the environment. And yes, I do say concurrent procedure, it doesn't have to be concurrent. Whether you do a meniscus transplant, a division ACL, and a MACI, and you name, if you do that at the same time, that can be a pretty long procedure, especially if you're not used to doing them. And in that case, have a really low threshold of just separating things out. I would try and group extra and intra-articular procedures together, so that you don't have to go in and out of the joint multiple times, and what I mean by that is maybe do your osteotomy first, let that heal, get your motion back, and then you come back and you do your intra-articular procedure. I wouldn't do an ACL and then come back later and do a meniscus transplant because that makes it more difficult, and I also wouldn't do a meniscus transplant and then come back later and do your ACL because they might have an instability event and tear up the new meniscus, so those I would always do at the same time. But I have a little laundry list of what needs to be done and see if logically you can group those things. So let's talk reality. This is a case of a 29-year-old healthy male. Two years ago, he had a microfracture of the medial femoral condyle and a partial medial meniscectomy, and then that didn't give him the pain relief he had had hoped for. Quality of life was impaired, so he went, I forget whether it was the same surgeon or a different surgeon, a year later, and they did a revision with a fresh osteocondylar allograft. And then he had persistent medial pain, and he looked again for an opinion, and people said, oh, you have already failed two cartilage procedures, you need metal and plastic, you need a medial uni. And I mean, that's a hard thing to do in a 29-year-old, especially if you look at this MRI scan. You see the graft looks a little funky, but his tibial plateau is totally fine, the medial femoral condyle outside the graft looks fine. So to do a uni is allowed there. So he thought it was allowed there, and he asked me, and I was surprised that I was the first person to actually do alignment x-rays. So this was his alignment, and he was a pretty significant varus. And looking at everything else, I can say the osteocondylar allograft is maybe a little bit thick. So the question for him was, well, he definitely needs an HTO, but does he also need a revision of his osteocondylar allograft? So I did a scope, and at the time of the scope, his graft actually looked pretty good. There was no instability, and because of that, we decided to go ahead with an isolated HTO. And sure, I could have done an OCA at the same time. You know, every time you do something, there's a risk for failure. So if something's not too broken, maybe don't mess with it. And that's what we decided to do for him. This was an HTO, and he did fine after that. So this was not necessarily a failure of the osteocondylar allograft itself. It was a failure of decision making, and those are ideal cases because we were able to figure out what was wrong or what wasn't done the first time around and do it better second time around. So in conclusion, how do we manage failure? Get your diagnosis right because you can't fix something, but you don't know what's broken. So get your MRI scan, get alignment x-rays. I like CT arthrograms for failed OCD fixations or osteocondylar allograft where you suspect that something's going on in the bone. MRI scan sometimes has a difficult time figuring out bone. A CT arthro has a beautiful resolution, and that can really help. For example, if this is an OCD lesion that has enough bone on it that you can fix it, or it needs to be a reconstruction with allograft or ACI. And then I use a lot of diagnostic arthroscopy, and I tell patients, like, I sort of have a gut sense and a notion what's wrong with you based on your x-ray and MRI scan. But this is not your first time around, and ideally we'd get it right this time. So if that means that you have to do one additional arthroscopy, so be it. It's a staging arthroscopy. I can poke around. It helps me think through everything that's wrong. If someone had an ACL before, I can really do an examination under anesthesia. If someone had partial meniscectomy, it helps me decide does the meniscus look bad enough, where I would say a meniscus transplant is better than what he has, because meniscus transplants are not perfect. So you really want to make sure that structurally you improve what they have, even if what they have is not perfect. And if you can't find anything structurally wrong and they have pain, try and resist this. Just do something. It can't be worse, because yes, it can definitely be worse. And I've seen patients who've had five, six, seven operations and everyone poked around. It's a chondroplasty and a lateral release and a plica resection and a synovectomy. No one ever actually fixed something because no one could identify what needed fixing, and some people just have pain. And as frustrating as that is for everyone involved, I mean sometimes we just can't fix things with the knife. And then if you do find something, set the right expectations. Revision surgery certainly has a failure rate that is as high or higher than a primary procedure, and they need to know that. And try and get the emotional component out of this relationship if it's your own failure. If you're cleaning up somebody else's mess emotionally, that's much easier. If it's your own patient, that's much more difficult. And I talk to patients, whether they're my own failures or somebody else's failures, about this rapid cycling. And what I mean by that is you do your primary procedure and the expectation is, oh this is this is going to be fine because your chance of success is like 80 percent, but then you fail once. And then you do the next procedure and all of a sudden it's flipped. Now you don't expect success because you've experienced failure before. Now you're super cautious and you're pessimistic and you expect failure. So I see patients who after revision procedure come back at six weeks and they say, doc this failed, something's wrong, I know it. And if after a primary procedure someone at six weeks says I'm not feeling better, then you would say of course you don't feel better, it's only six weeks. But after revision everyone is more guarded and revisions take time to settle down. So say look at this point I just don't know but you need more time and we'll get an MRI scan at some point at the right time and you just need to have the patience. But that that's a hard discussion. So I hope that this has been helpful to you and if you get failures don't lose hope for cartilage repair as a field. 15 to 25 percent of cartilage repair procedures will fail. And if you look at ACL reconstruction most of us do that and they don't we don't really think twice about it. But in certain patient populations the young flexible females that go back to to soccer they have a 15 to 25 percent failure rate. Will we do an ACL on those? Sure we do. So unfortunately these things happen we can just try and do the best job we can. If you're faced with someone who has a failure really talk to the patients see what their goals are. Some really just want to be reassured that they're not really losing out or causing more damage if they keep using their knee. They feel something's wrong but they can actually live with it. In that case it's fine to do conservative management. Sometimes if you can identify what went wrong if you think you can do it better then yeah go ahead revise it. And last but not least some patients especially the ones that had progression of disease where now the whole joint is beaten up metal and plastic whether it's a uni or a total might be the right choice. And it always feels like we're giving up but for some patients it's the right thing to do. So counsel the patient overall revisions and that's true for for most revisions of just about anything it's about a 60 percent success. So better than 50 50 but certainly not not a guaranteed success. And I keep harping on this but if revision is an option try and figure out what went wrong so that that you can do it better. And frequently the problem was the wrong indication or the wrong procedure first time around. Hopefully you can do that better or there are residual alignment or meniscus issues that haven't been corrected and hopefully you can do that better as well. So if you have any questions email me my email address is below and I thank you very much for listening in. Take care. Bye bye.

cartilage repair

failure management

revision surgeries

diagnosis

procedural errors

patient factors

structural pain