Thank you for the introduction, I'd like to thank you for the opportunity to present this as well as my co-authors. This study really looks at the ability to use oblong graphs and where the source of the graphs can come from and whether it needs to be the same area of the defect location or it can be contralateral. I don't have any conflicts that are associated with this, nor do my co-authors. We know that osteochondrial allografts have fairly good success in general, however when we get to larger lesions, as was discussed in the prior session, we can have challenges with using multiple plugs and these potentially have higher failure rates than when single plugs are used alone in isolation, but this is not the same treatment group, so these are different size defects between these two and it's not clear what two plugs versus one larger oblong plug would do and that is developing currently based on new techniques. So the purpose of this study was to virtually analyze the topographic and osseous matching of oblong plugs that were treated for medial femoral condyle lesions using sources from medial femoral condyles and ipsilateral and contralateral lateral femoral condyles. So our methods were taking 12 condyles from each side, 24 total. We scanned these with a 3DCT sequence where we sequenced out the bone and cartilage separately. We then created three different model types, donors for medial femoral condyle, donors for ipsilateral lateral femoral condyle, and contralateral lateral femoral condyle, all for medial condyle recipients. The model sizes included a 17 by 30 millimeter and 20 by 30 millimeter size, which is something that's clinically available now. When we looked at the mismatch overall, which was called the mean least distance between these when they are overlaid, and then we looked for a perfect match would be zero and obviously positive would be proud and negative would be recessed. We looked at the average step off between four areas on the periphery as well, so we did not just look at the overall surface mismatch. We also looked at how the edges line up when this is completed. This is what our results look like, and so this is getting to the articular surface matching. If you look at this image on the left, a white image is a good match again. Red is proud, blue is recessed, and you see that when we use a medial donor for a medial lesion, we see excellent matching and we see less than half a millimeter of mismatch. When we use an ipsilateral lateral femoral condyle donor or a contralateral lateral femoral condyle donor, this was significantly worse with regards to mismatch at larger sizes. The contralateral lateral condyle was not significantly different at smaller sizes compared to the medial side, so that was the closest one outside of a medial femoral condyle. This also, when just discussing the absolute values that we're dealing with here, the donor graphs were within one millimeter when it was a medial condyle and it was more than a millimeter when it was a lateral femoral condyle, which potentially could be clinically significant, but it's hard to say for sure. Similarly, the mean step-off was significantly greater for the lateral donors compared to the medial donors in all settings and at all sizes. And when we try to look at the distribution of the step-off, these plots essentially show in a circumferential fashion around the graft how much step-off is there, and you want this to be a circle around zero here. And so when you look at medial for medial, it hovers around zero throughout, but when you look at lateral for medial, it starts at zero in the anterior aspect, and as you go to medial or lateral, there starts to be more significant step-off, and that's what we found statistically as well, which I think intuitively makes sense based on the radius of curvature difference of the lateral femoral condyle compared to the medial. When we set this up for a perfect matching or the best matching possible, the cartilage surface, we then looked at the resultant osseous mismatching underneath, and even for medial femoral condyle, you can see this was rarely in the white zone, so there's usually some element of mismatch of being proud or recessed, however, that was significantly different with the lateral donors in all groups again. This part, I would say, has the least known clinical significance, however, it was the most significant difference with regards to the numbers. The limitations here is, just as mentioned, how do you translate this into clinical practice? This is a simulated defect, not an actual defect, and this doesn't tell us what the biomechanics does for pressure and point loading after this is complete. I think that the main take-home here is that we know that there's a good match with medial for medial donors. Lateral for medial donors may give reasonable matching for clinical tolerances, but if you don't do a lot of these cases, you probably don't want to go straight to a lateral condyle for these graphs, unless they are smaller, as there was a difference between the two. We need to keep in mind that the articular cartilage step-off is an important component, and you can probably accept medial lateral step-off as opposed to proximal distal or anterior posterior. And so, again, in closing, I would just say that if you're just starting out with this technique, I would probably recommend medial condyles only for the donor for this procedure. Thank you.

oblong plugs

femoral condyle lesions

graph comparison

topographic matching

osseous matching