You know, six or seven minutes here just talking about, you know, how to approach the patient with a cartilage lesion. I think no matter what technology we choose for cartilage restoration, it's really important that we all at least have some guiding principles for management. So for me, you know, after a good history in a physical, we really have to standardize our imaging approach. You want to make sure you get good quality x-rays, alignment film, and then a recent MRI. Even an MRI seven or eight months ago just probably won't cut it for a cartilage patient. So what am I looking for? I'm trying to decide, is this a focal or diffuse process? I'm trying to understand background factors. Why did this injury occur? Is it a traumatic injury? Are there some predisposing factors that we need to address? And then really scrutinizing the MRI, looking at the size, looking at the location. Is this cartilage? Is this bone and cartilage to help me plan for surgery? So what does imaging tell me? Well, I'm trying to decide, is this a focal defect or diffuse? And for me, I live in Minnesota. We have a lot of potholes in the road, so that seems to resonate well with patients. But if you have a single pothole in the road, you're able to fill it. That's a good cartilage defect for surgery. In the springtime in Minnesota, we often have more potholes than road, and that's really more like arthritis. It doesn't matter how many potholes you fill, new ones will form, old ones will break down. So that's not really a good candidate for cartilage. So take this 44-year-old. You can see already joint space narrowing and varus malalignment. You get his MRI, you can see diffuse cartilage changes, bone edema. To me, that's too far gone. You can't really distinguish where the bad cartilage stops and the good cartilage starts on his arthroscopy. So this is one that's more arthritis, and this patient could benefit from an offloading osteotomy at a young age, and we try to preserve the joint space that they have. He's at five years, still doing well without any cartilage restoration. So background factors. No matter what technology you'll hear from us today talking about options, we really have to respect and understand the background factors. We looked at cases referred to us over a five-year period of time. These were cartilage restoration cases that failed, and we tried to understand why. In the majority of cases, malalignment was either unrecognized or unaddressed. So if you're thinking about it, you probably need to address these background factors. We think about a valgus osteotomy for the varus knee. We think about a varus osteotomy for the valgus knee. But remember, we're not treating x-rays. Watch your patient's walk. Do a thorough examination. This is a patient with a triple varus gait that doesn't need an osteotomy at all, just needs a ligament reconstruction. The patellofemoral joint, I won't get into in too much detail. Andreas and Jack are the experts here, but I think this case really understands the principles or highlights the principles. This is a 19-year-old with a painful cartilage patellar defect, and he really has every background factor known for the patella. So we perform a first-stage varusation distal femoral osteotomy. You can see intraoperatively here, even with passive range of motion, he still has a pretty large J sign. That's just a hostile environment for any articular cartilage to survive. So we have to correct those factors as well. At the time, ACI was available, so we performed an ACI implantation to this pan-patellar cartilage defect. More importantly, though, we addressed the supratrochlear bump, the instability of the MPFL, and performed a tibiotubercle osteotomy. And here's the patient at three months. It's a lot of surgery, but when you get those background factors right, it now gives you a better environment for the new cartilage to be loaded. Then finally, when we're looking at lesion factors, for me, size is very important. Sometimes makes the decision that we're going to perform an allograft or we can perform an autograft. Size can be very tricky in an MRI. You look at your radiologist's report, and they have different dimensions on there. What I like to do is look at the axials. To me, this replicates the knee in 90 degrees of flexion at the time of surgery. I take that distal cut. You can actually see the femur here. It looks like it's the tibia, but it's the articular cartilage surface of the femur. This is one where you get the geometry and the size very precisely. This is an uncommon case where you can do an autograft transfer for a long linear lesion. We also like to understand, is this cartilage or is this bone and cartilage? Here's a 36-year-old with a trochlear lesion. That's actually an old OCD lesion, clearly has bone involvement. So I'm going to use a bone and cartilage solution. You'll hear more from Dr. Caldwell on that as an option. This is kind of a companion case. Here the bone is pristine. You can see the subchondral bone looks normal. So this isn't one I want to violate necessarily, that bone. I want to perform a surface treatment. At the time, this was an ACI case. I like to know, is this an acute or chronic problem? Because I think it has a large factor for prognosis. These are two similar patients that presented with a so-called acute injury. This one is truly acute. You can see very well demarcated borders. You can draw a pencil line. That truly is an acute cartilage injury. This patient also presented with what they thought was an acute injury of a patellar instability event. But here you can clearly see sclerotic margins, very chronic appearing lesion with subchondral edema. That patient's going to fare different, and maybe we have to think about that patient differently compared to the first one. In terms of location, I think it's always good to anticipate the needs of that specific location. This is a post-lateral patellar dislocation cartilage defect that was microfractured. This is going to be predictably an uncontained defect. In this case, we consider juvenile chondral allograft. The strategy for containing it in this case was a collagen membrane, but you should anticipate some of those issues before surgery. Then perhaps the most important is really managing expectations of the patient, spending that time really with them in clinic, maybe more than once before getting into surgery. I think we all want improved pain and function and durability with our cartilage restoration. Our patient's expectations may be that they're fixing this to have a quote, normal knee in the future. I think it would be a mistake if we led them down that path. So let's just take one benchmark of improved pain. The patient might be under the impression that they'll be pain-free after surgery. I think we're trying to coach them. We can certainly improve your pain with ADLs. Where's the truth in that spectrum? Well, this is the summit data. That was Macy versus microfracture. This is five-year outcomes. The Macy patients did better for both pain and function based on KUS scores. But what does it really mean? Well, both groups improved, but at a score of 82 for KUS pain, what does that mean to a patient? What would that patient look like? So if we kind of calculate that score and how that patient would answer those questions, they would still have weekly pain. They would still have mild pain with twisting, turning, squatting, walking on level ground, and standing for prolonged periods of time. So clearly that's not a pain-free knee. That's one where we've improved their pain substantially from baseline, but certainly not normal. So finally, you have to ask yourself, how does that patient in front of you compare to what's published in the literature? On the left is an ideal lesion that we'd all love to see. Unfortunately, we're treating a lot of multifocal, more challenging lesions in our young patients. On the left, you see the results of the Phase 2 NeoCART trial. By design, these were all simple lesions, no combined procedures. If you look at Andreas' work on the right, multifocal defects, only 8% simple lesions. Two-thirds of those patients got osteotomies, a longer follow-up, so a longer opportunity for those patients to potentially fail. So you really just have to be careful what you're looking at and compare apples to apples. So in conclusion, I think it's important to get it right the first time by developing a standard approach for every patient. For me, that's a standard set of x-rays, a recent MRI. Really want to understand those background factors and address them. To me, if you study your MRI carefully, hopefully you won't have any surprises at the time of surgery. And I think really spending the time to manage patient expectations, I think this will pay dividends during their recovery and overall help them with their decision-making. So thank you very much. Next we'll have Dr. Rachel Frank. She'll give us her thoughts.

cartilage lesions

guiding principles

standardized imaging approaches

managing patient expectations

standard approach