I have disclosures, you can look them up. This is a 28-year-old that has classic retropatellar pain. They had extensive conservative management, normal x-rays, MRI demonstrates significant damage behind the patella, the cartilage, grade 4 in nature. Open examination showed diffuse grade 4 changes in some 3 spanning in between there, so fairly uncontained lesion, and actually really had a pristine trochlea. So this is unipolar patellar disease that's uncontained and pan-patellar. So for me, I would recommend an osteochondral allograft for this patient with a straight anteriorization osteotomy based on their general alignment, and you can see that here. Obviously you've heard from some of the talks, we try to optimize the viability of osteochondral allografts. It's the only thing that puts in normal articular hyaline cartilage, and so the idea is to keep the viability and the biologic activity intact, certainly of the cartilage, and have it integrate. If you have both of those happen, you should have structural success at a minimum. If we look at this, there's a lot of Dr. Cole's work here, Dr. Bugbee. You start out with, it's not applying biologics, but you need to maintain biology here. So you want to have good viability. If grafts are beyond 28 days or even up to 28 days, there's certainly worse viability there. It's not exactly linear. So if you look at clinical outcomes, there's conflicting data as to whether or not viability affects clinical success rates. But if you look at the cutoffs used for these studies, both of them that look at 20 days plus start to get worse. So it seems like 20 days or less seems to be ideal for even clinical outcomes. Obviously there's a lot more to this. There's a lot of other factors to control for. But it's something to use as a guideline, and that does line up pretty well with the viability data that was done several years before that. If we take a look at some recent data that we're doing that's currently unpublished, we just looked at the effect of the reamer. So you basically get thermal necrosis of the osteochondral allografts when you ream and you generate heat. And so this is 61% viability after significant pulse bulb irrigation, that it's being done as fast as a hand can do it. That's compared to about 85% that these grafts had coming in, or 80% even. We did submerging of the graft and found that it almost mitigated that completely, and certainly statistically it did. And so we tried to minimize thermal necrosis. The problem is the recipient site is subject to the same problem, so we're probably killing cells in the periphery of the recipient site that may or may not affect delamination down the road. And it could either be progression of disease that's natural, or it could be that we're advancing that process. You also try to maintain viability by not hitting it as much as possible. With different amounts of load, you have different amounts of death in the beginning. But by day eight, all of the impacts ended up with the same amount of death, which was an 80% reduction in viability. So I try to dilate and manually press fit grafts as much as possible without impacting them unless absolutely necessary. It's also helpful to remove the immunogenic components. So we were hearing the discussion about the bony components and the active cells in the bone, is that helpful or not? Certainly it seems like the marrow elements are not helpful. And so we do want to remove those. This study showed that using pulse irrigation as well as high pressure CO2 helps remove it the most efficiently. Here's an example of the CO2 being applied and washing out essentially any aqueous components here. And then if you see if you are going to apply a biologic, you can see on the left the application without. It's very much oil and water so they don't mix versus the sponge type effect that you get once you eliminate those factors from the bone. So if you wanted to carry more biologics, you're probably getting a higher dose into the body and better accessed with your biologic. If you're going to use a biologic, the one that has the most studies and the most data is bone marrow aspirate concentrate. And there's several studies that have taken a look at this. The data again is slightly conflicting. But if you look at some of the details it is helpful because they use different metrics for outcomes. Some are MRI, some are CT, some are x-ray. We were part of a JRF funded randomized clinical trial looking at bone marrow aspirate concentrate versus just traditional preparation and saw that there was the same overall amount of cysts that formed but there was more small cysts with BMAC and less large cysts. So it seems like we shifted to smaller cysts which potentially is an indicative sign of better integration of the bone. And so these are all the studies that exist to say it helps, to say that it doesn't, only the one that I just mentioned is a prospective RCT. So this patient did well. This is their initial post-op visit which he happened to be doing very well. He didn't have much of an effusion. He got his strength back right away. So he was a pretty fast recovery. But not everybody's like that. And some of these patients come in with an immediate post-op hemarthrosis. This is some data from work that Dr. Cole and I both did looking at aspirations after osteochondroallograft transplants. And we had at two weeks, 83% of our patients had a hemarthrosis which we know is chondrotoxic and a problem. So we have this hostile environment we created when we went through all this work to put in a nice healthy graft. So I think that's something that we need to consider moving forward is postoperative management of the cytokine profile that patients are experiencing and the graft is experiencing. Here's a trend of the MMP, so matrix metalloproteinase, in the first six weeks there's a significant peak in these patients. And there's changes that happen up to six months and even a year. And in our study we did find, these are not serum markers but synovial markers, that IL-1 levels at two weeks correlated with six-month clinical outcomes. And there's other work that we did that showed that preoperative factors are more important than any structural factor of the cartilage defect itself. So I think we're going to see more postoperative injections from cartilage transplants. I'm pretty aggressive with aspiration for that reason as well. I think that if we can try to decrease the damage that we're causing and then give it the best opportunity as possible to heal with the current methods described, I think we can improve the outcomes and bump that 85%, hopefully up to 95%. Thank you.

osteochondral allografts

patellar disease

anteriorization osteotomy

graft viability

biologic activity