All right, thank you, I'd like to thank the program committee and the members for having me here and letting me present. I'd like to thank Dr. Lowe for partnering with me and supporting me in this exciting journey and slope. I have no disclosures, the others are in the program. So the dilemma for us, and this is what comes into clinics, the 42-year-old Ironman competitive athlete, three failed ACL reconstructions, ACL and meniscal deficient. So typical AP and lateral radiographs you will obtain in your clinic. As we know, for a failed ACL, and we're talking about slope quite a bit here, there's a higher level of failure and much lower survival, and some fairly large series that got everybody looking at this topic. So for us, anecdotally we noted that we saw differences when we measured the posterior slope using the standard radiographs, and at some cases we're very surprised by those same measurements taken off a long-standing x-ray. And so we hypothesized that these conflicts are real and not so much anecdotal and wanted to see what our series were for us. We needed to define it, so short segment would be what you guys think of as standard lateral knee radiographs, whereas long segment include the knee and the ankle so that that can be adequately measured. Our hypotheses were twofold. One was that there was a difference between the long-standing and the short-segment radiographs, and that for our practice it was imperative to include the long-standing radiographs to fully understand the deformity when you're talking about these complex deformities. So in the 90s, Paley defined measuring long-segment radiographs on the lateral views, and these have some examples here for you. And then for short segments, there have been several studies that talk about the proximal tibial anatomic axis, which I think has been well-defined, but the question is, are they really similar? So again, back to our dilemma, ACL and meniscal deficient. And then when we get our long-segment radiographs, his posterior tibial slope is 18 degrees, but he's also, this is a left leg, he's also in 6 degrees of varus, so not a uniplanar deformity. So for our cohort, we looked at all patients. This was failed ACL reconstructions, a single-surgeon practice over a five-year period that we had obtained long-standing lateral and APU radiographs. We measured them in the coronal plane and then also in the sagittal plane. We calculated it using the aforementioned short-segment calculations and then also long-segments and compared the results, two measures to compare. So our results, we had 35 patients. I want to highlight a few things. The inter-rater and the intra-rater reliability was quite high in all the measures that we made. However, when you boil it down to the individual measurements of the same bone, either short-segment versus long-segment, two-thirds had an absolute difference of greater than 2 degrees. So 3 degrees or more, both using the medial plateau as the standard or the lateral plateau as the standard. And then 57% of the images had at least 2 degrees of coronal plane deformity. So we've tried to simplify posterior tibial slope as if everybody has neutral coronal alignment. But in our series of failed ACLs, more than half of them had at least 2 degrees of varus or valgus malalignment. There was a slight increase in the mean if you look at the lateral plateau measuring for the short versus the long segment of about a degree. But if you look at the variability between the means, it was low. But each individual one could have a high variability. We saw variability up to 7 degrees. So a short leg would measure 1, and then another one would measure 7 degrees higher. So there was a lot of variability when you compare the short leg and the long leg, which I think is clinically extremely relevant when you say 11 degrees is fine, but 13 degrees may need an osteotomy. So in our series, 12 of the patients ended up having a slope-reducing osteotomy as part of their revision ACL reconstruction. 66% of those patients had coronal malalignment more than 2 degrees. In 5 of those, about 40% required biplanar correction to address the multiplanar deformity. So case example, I have a short segment radiographed on the far left, and then the long segment adjacent to that. And you can see 76 degrees posterior tibial or 14 degrees posterior tibial slope versus 21 degrees posterior tibial slope. Same patient, just measuring the entire bone. Neutral on the AP. And in this case, if we extrapolate that out, it's easy to see on a short segment how you could have some variability, but when you move to a long segment, you can realize you're not going to make your distal points that far apart. So I think that using the entire bone, you can see why the variability may be less. And in this case, that information was extremely pertinent because this patient went a diaphysal slope-correcting osteotomy, if you will, and his new slope is 11 degrees without affecting his coronal alignment. And we believe that was the best way to achieve it in this case, which we would not know or appreciate if we only used the short segment radiographs. So discussion, consistency is important, preoperatively, assessment and determining outcomes, and limb deformity principles. They use the entire bone as we were taught in the 90s, and why should we measure differently? So some variability exists in the literature. Some very thoughtful surgeons, I just took some radiographs and overlaid them measuring short segments even within our own measurements here. And you can see if you overlay the tibias, these are all super tubercle osteotomies. As you can see, even within the same patient, same measurement, it's a six-degree difference. We use the perfect circle technique, same measurement, same study, eight-degree difference. So when we're trying to make critical decisions off of a few degrees and we're having this high variability, I think every degree can count. This was a study that LeProd published about the importance of long standings on the AP, and we would like to advocate that's probably no different in the lateral. So this is limitations, small series, retrospective. There's really not a gold standard, and it's a revision ACL cohort, so I'm not sure if this is universally acceptable. And we're not elucidating the importance of the posterior tibial slope in this study, but really questioning if we're consistently measuring what we are trying to measure. So in conclusion, long segment radiographs more completely evaluate the complex deformities compared to the short standard. Sixty-seven percent of revision ACL patients in our cohort had an absolute difference of more than two degrees comparing the short and the long segment. Half of them had a coronal malalignment, more than two degrees, and 41% of our slope corrections involved biplanar osteotomies to correct both deformities. So in the revision ACL patient, we recommend obtaining long segment AP and lateral radiographs as essential imaging. Thank you.

medical conference

long segment radiographs

ACL reconstructions

coronal malalignment

revision ACL patients