Time for Q&A. Please feel free to come up to the mic or enter your questions on the app. We do have some questions that have been submitted already. The first one is for Dr. Dennis. Given that you have identified that all of the failures had either increased TTTG or CDI, did your group perform a subgroup analysis to determine the recurrent instability rate for patients who would have been indicated for TTO or other procedure? Thank you for the question. We haven't performed a subgroup analysis yet, but once we have completed enrollment for the study, we'll definitely do that. So we have a bunch of questions. We're not going to get through all of them. We'll try to do the best we can. Just to follow up on that, so in any sense, Dr. Dennis, when providers need to identify that a patient may need something more than MPFL alone, if you were counseling somebody that said, please explain your results to me, when do I need to be thinking about more? What do you take away? That's a great question. I think that's the biggest take-home point from the study. When we talked about the exclusion criteria, I think those exclusion criteria are going to help shape identifying patients who need an additional procedure and a bony realignment procedure. Specifically the signs of maltracking or the jumping J sign is probably the biggest one. »» Okay. Next question for Dr. Campbell. The rate of TTO in female patients was higher, though not statistically. Did you look at return to sport and VAS at sport without TTO? »» We did not do a subgroup analysis looking at a TTO return to sport. Unfortunately I can't really comment on that, but overall, you know, VAS was higher in our female patients. They did have more TTOs than males, but it wasn't significantly different. So it could play a role. »» Thanks, Dr. Campbell. Dr. Schupenstein, Dr. Duke, if you had a question, you can pass it to them. »» So Beth Schupenstein from New York. I'm actually paper 54 for Dr. Krukberg. The rates that you, great paper by the way, really nice, the rates of failure for MPFL repair are reflective of what the literature shows, very consistent with previous literature on repairs. But the rates of MPFL reconstruction are higher than we would expect. Any ideas as to why that might be? »» Yeah. I think part of it is the length of follow-up with these. A majority of studies usually have follow-up up to five, six, somewhat getting close to seven years. And so at nine or so years you can start to see that some of the MPFL reconstructions that typically would have been doing well at the early midterm mark are now failing, especially if they continue in sports. »» Just as a follow-up to that, can you remind us what the indications were for repair in your group? »» Yeah. So I think the indications of repair were typically mainly either femoral or patellar avulsions, especially if there was some bone. I think that's an indication for MPFL repair. And also at the time of initiation of the study or when we were looking back at these patients in the early 2000s, you know, MPFL repair was still something that was considered by many surgeons. »» And the repair was, again, in the acute setting more so than the reconstruction, yeah? »» Yeah, exactly. And so that was demonstrated by the duration or the interval between the time of injury and the time of surgery. »» Dr. Dudek? »» Just for the sake of discussion, I think a lot of these papers go together really well. So if you look at Robert's paper and multiple dislocations, and those are not going to do as well, and then Elizabeth's great work, but I just cringe at the title. And I just worry where some people stop reading at the title. And I think this, you know, the audience needs to appreciate what you are trying to bring out. There's a subset of people that just got excluded and treated differently. And to understand what that represents. So an unloadable lateral cartilage legion, that's significant maltracking. A jumping J sign is a bad vector, probably plus significant alta or dysplasia. And then you had just a handful of failures. Some would argue 5% is high from what we could maybe achieve and hope to achieve. But I think one had a high TTDG. I think we all recognize that number in isolation is probably not that important. But two had high PTLTR, which can be high in the absence of the TTDG number and may reflect other things like alta and valgus. So I think you're really getting at important stuff. And you put the registry paper together with the Jupiter study. I think we're really moving in the right direction. But for discussion, I just wanted the audience to appreciate you're not taking everybody, regardless of the TTDG, and applying it in isolated MPFL. And that's an important point not to miss. Okay, for Dr. Henstenberg, were you able to look at the difference in op times to evaluate the time of cost based on graft? The question was about operative times? Yeah. We did not look at operative times, but that would be an interesting follow-up study if we were able to get the cost of the allografts and time spent in the OR and compare those. Maybe a follow-up question then. Do you think the results were impacted by the fact that morphologically both groups had minimal anatomic risk factors? Yeah, and that was part of the study was trying to make a homogeneous cohort to actually just directly compare the two graft types and see what the failure rate was. But in practice, there is a lot more heterogeneity. I think the question is too about whether if there was more morphologic variability, if you think the results might be different, if that might power the study more to identify results between graft type. Yes. Yeah. I think that is potentially something we can do in the future. For the last paper, there was a question about what was the time to surgery for MPFL repair? Yeah, I would have to reference the table. I do know the interval was significantly shorter with the MPFL repair compared to the reconstruction, but we typically try to get to these patients as quick as they have their second patellar instability episode. I don't have the exact month in my head right now. Dr. Hart? I just wanted to ask Bob Magnuson, I thought you brought up an interesting point. People think about recurrent dislocations doing worse maybe because of the cartilage damage, and you showed at least in your cohort it wasn't true, although we don't know the location. But I heard a different thing come out of your paper today, where it's kind of like an ACL. The longer you have ACL instability, the more you may stretch secondary stabilizers. So my question to you is where do you think hyperextension of the knee falls into all this? Because I think that to just look at Bayton's score but not hone in on the hyperextension at the knee level, we're missing a potential variable that's going to contribute to your outcome. Yeah, absolutely. I think that's another underexplored contributor to the outcomes of isolated soft tissue surgeries for sure. We could look at generalized ligamentous laxity. We could look at localized hyperextension of the knee. All these could potentially accentuate ALTA. We could look at the degree of manual translation. There's a lot of factors that may contribute to the soft tissue laxity in a myriad of ways that we don't understand. So clearly we've got a lot to learn still about which patients do well and why. Another question for you, Bob. In your paper, you had looked at chondral defects and the presence of or not. What was the cutoff for that? I'm sorry, you said? For when you had looked at chondral defects in your patients, what did you use as a cutoff? Was it any or? So for the purposes of this study, we weren't really too focused on the chondral defects. We just described anybody who had a grade 2 or greater defect anywhere in the patellar thermal joint as having a chondral defect. And certainly we could delve into that a little bit more. The vast majority of these were on the medial patellar facet. These were generally not your classic unloadable chondral defects because all those people, the vast majority of those certainly would have been excluded from this study because we would typically offload those with a concomitant osteotomy. So these are mostly grade 2 to 3 defects, mostly on the medial patellar facet. Okay. I think in order to stay on time, we'll have the speakers. You guys can go back to your seats and we'll have Dr. Sita and Dr. Hart come on up here. Yeah, I just want to thank the speakers. Thank you, guys. Thank you.

Q&A session

subgroup analysis

indications

failure rates

operative times