All right, next I'd like to introduce Dr. Mark Hurd from Banff Sport Medicine who's going to talk to us about sagittal tibial slope in revision ACL reconstruction. Mark. Thanks, Mike. Thanks for inviting me. I want you to listen to this talk in reference to the last two talks. And I have no disclosure, but I want you to think of this as risk reduction in re-injury of the ACL. So we all know there's unmodifiable risk factors such as sex, age, collagen, shape of the femoral condyle. But there are modifiable risk factors, and I will give it to you. When we're talking ACL in the knee, most of the talks happening in the conference are addressing modifiable risk factors. Having said that, we're just touching on slope of the tibia as a modifiable risk factor. So I want you to kind of think about that. So we're going to look at what's happened in the past and what research is out there, because I have to admit, it's quite sparing. What's going on in this slide? It's dark. Yeah. So our veterinary friends are doing primary ACL reconstructions by doing a slope-decreasing ACL. They used to use fishing line and stuff in the past, but they're actually kind of ahead of us. And they realized that there's a real power in decreasing the slope of the ACL. So I give them some kudos of being a bit ahead of us. Way back in 94, Henry Desjardins, David's father, did a radiographic comparison of ACL-deficient knees and increased the slope of the tibia and found, yes, in fact, we get increased tibial translation. Giffen et al. kind of defined normal tibial slope in humans after looking at several thousand as about 7 to 10 degrees, and I think we're all kind of comparing to that. And a beautiful bit of work was done by Lucy Solomon, a gal in Australia who studied Leo Pincheski's 20-year follow-ups of hamstring ACLs, and she found that those under 19 years of age and those over 12 degrees slope, 12 and over, had a 78% failure rate or a 22% survival rate in that time. That was quite telling for us to say, hey, maybe we've got to look at tibial slope as a risk factor. So I think we can all agree that posterior tibial slope is an independent risk factor for failure of the ACL. Well, how to decrease posterior tibial slope in the revision ACL, and I'm going to put it to you that today, really, it's a closing high-tibial osteotomy. I'm not going to go into the details because I don't have enough time in this talk, but beautifully brought up one or two stages, and I'm going to be honest with you. If there's going to be bone grafting of tunnels, I'm going to do it in two stages. And if I don't need to bone graft tunnels, you can tend to do it in one stage. You can deliberately use a tubercle osteotomy when you're starting to learn these. It opens up the whole front and makes the operation a lot easier, and you can put fixation on both sides of the osteotomy. And I have to admit there's no great fixation in these, and I'm still experimenting from staples to screws to... I'm actually using hind foot locking plate systems for fractures recently to get that locking scenario to get them moving faster. I do want to point out that back in 2011, Frank Noyes and Ned Amendola published this paper on the concept when you're down in the metaphysis, the tibia is a triangle. And unless you keep an anterior hinge and completely osteotomize the posterior tibia, it is super hard to decrease tibial slope with an opening osteotomy. So if you're approaching a person with a 12-degree slope and thinking, oh, I'm going to unload that little medial OA with an opening posterior-based, it's really hard to decrease that slope. And it's a lesson that I've learned over my practice. Actual results in the literature are sparse. But back in 2014, Bernard Sonnery had five cases, multiple revisions, all three revision ACLs. They had good radiographic outcomes, good clinical stability, and he suggested they should only be considered in the multiple revision setting. David DeJure did nine cases, and again, the same sort of consequences, said, you know what, they look good radiographically, they're clinically okay, but I would only recommend them in the multiple revision. We looked at our experience. We combined 23 patients with Al in London and Volker in Pittsburgh and found, yes, we were able to get good radiographic results, we were able to get good stability, so it's good at getting stability, but we only had FAIR-reported COUS and IKDC. But again, these were the multiply revision patients. So there's limited out there. They're always being performed on multiple revision patients. Yes, we can get the knee more stable and less likely to re-rupture the ACL, but they're not doing so well. So I think we have to go back to the evolution of risk reduction. Great talk, should we do ALL, should we do LAT, I think that's got to start coming onto these panels more about slope-reducing osteotomy, and possibly sooner. We've got all these other risk reductions. I think we've got to look at doing that. So I think we need to recognize slope and recognize the risk of posterior tibial slope and graft failure. Consider earlier intervention with a slope greater than 11 degrees, and we also should get some specific fixation. And I put forward we need to do a larger multi-center trial with more control. Thank you.

sagittal tibial slope

revision ACL reconstruction

modifiable risk factors

veterinary surgeons

hamstring ACLs