Thanks for the opportunity to present our work with my co-authors, which I'll share with you. My primary disclosure. What I want to talk about is what we call the Elmort lesion, which is lateral muniscus oblique radial tear that you commonly see with ACL injuries. It's not a root tear. We're talking about a posterior body tear. It's seen with ACL injury, probably from the pivot shift subluxation. In the past, we've been told to leave this tear alone, that it's going to heal when you reconstruct the ACL. But the biomechanic importance of this lesion has never been studied. So the basic premise for our study came back to this classification study we did with my co-authors from the Mill Clinic. We looked at 600 consecutive patients and categorized these lesions. The type one lesion is seen here, was close to the root, a little paraplegic tear. Type two was within 10 millimeters of the root. We saw it about 13% of the time. But the two we saw the most with ACL with 30% were a type three, which is greater than 10 millimeters from the root, but not all the way through the muniscus. This is the type four, which we saw the most, 48% of the time in our ACL tears. This was greater than 10 millimeters from the root and extended to the capsule. This will be your classic type three tear that you see with an acute ACL tear. We've all seen that lesion. If we can go to the next slide, if you can advance that next one for me, please. Some reason it's not working. There's the type four. You see there's no posterior horn here. It's commonly seen. It's flipped up and scarred to the ACL. So we free this tear up and you'll see this is an extremely large fragment. This is not a root tear, but that oblique posterior horn tear that you see. So what's the significance of these lesions? You advance that for me, please. So we looked at this in two different ways. Our first study that we published last December looked at the importance of the lesions with an ACL tear. So we made the L-more three and four, which were most common. We made those tears and we looked at a robotic mechanical study. We looked at the anterior drawer and pivot shift. We also had an ultrasound to assess for meniscal extrusion. So here's our methodology. Here's a type three tear. Here's a type four. So we looked at the intact ACL. We cut the ACL, made a three, studied it with the robot, made it with ultrasound, then we made the four. So our first study conclusions. We saw increased anterior instability, both with the anterior drawer and the pivot shift compared to an isolated ACL tear. The lateral meniscal extrusion with our ultrasound was also exacerbated. So these lesions are important. They increased instability with an ACL tear. So the next part of the study was looking at this with reconstruction. This actually just published online today and the results of looking at it when we did an ACL reconstruction. So more complicated study. What we did is we looked at intact, tested that, cut the ACL, reconstructed the ACL, made the three lesion, repaired it, and did a partial meniscectomy. Same thing for the four. This is how we repaired it with a side-to-side suture-based repair. So our second study results, we cut the ACL, we had increased anterior translation for anterior drawer and pivot shift at all flexion angles, as expected. When we reconstructed the ACL, we restored stability to normal. Untreated L-mort III and IV lesions increased laxity with the ACL reconstruction and meniscal extrusion when they were left alone. However, when we repaired those lesions, we restored stability back to normal. So you can see here in this slide, as I summarize our findings with anterior drawer and pivot shift, also with meniscal extrusion, you can see with the tear, we had increased laxity. The arrows point to significance. And so here when we did the repair, we brought everything back down to normal for our biomechanics. When you did a partial meniscectomy, you can see more positive arrows of instability. So taking the meniscus out in a type III L-mort was worse. Then we did a IV, and you can see a IV in combination with ACL reconstruction, even more instability at all levels, more meniscal extrusion. Repaired the IVs, biomechanically restored stability, as well as meniscal extrusion back to normal. The worst was this. If you had an L-mort IV lesion and did a partial meniscectomy, you can see the number of significantly increased instability present, and that also applied to meniscal extrusion with those lesions. You know, in the past, we've been told to treat these lesions with benign neglect by other authors and that they're going to heal. But even if they heal, do they heal correctly, and do they restore normal meniscal function? What about later osteoarthritis development? So our conclusion is, based on our biomechanical studies, is these lesions should be fixed in combination with ACL reconstruction. We prefer a meniscal-based suture as opposed to a capsular-based. So you have spanning sutures between I and III, done arthroscopically, tying an arthroscopic knot to preserve meniscal motion of the lateral meniscus. So our conclusions were, this was a fairly common lesion. We saw 12% in our initial classification study. L-mort III and IV were most common, which is what we studied. Untreated lesions have adverse consequences on stability for the anterior joint, the pivot shift, as well as meniscal extrusion, which we looked at with ultrasound. Especially the L-mort IV lesion, which you'd expect, because that's a complete radial tear all the way to the capsule. And when we repaired these lesions, we restored stability back to the intact state. So it's best to repair them for sure. Leaving them alone is not great, but partial meniscectomy is absolutely worse. Thank you.

video

knee injury

Elmort lesion

lateral meniscus

ACL injuries