Clay Nuelle:                        Welcome everyone. I'm Dr. Clay Nuelle from the University of Missouri. I have the pleasure of being joined on the podcast today by Dr. Bruce Levy. Dr. Levy is a professor of orthopedic surgery at the Mayo Clinic, and is a world renowned surgeon, researcher and thought leader, particularly when it comes to multi-ligamentous knee injuries and reconstructions. He was a senior author on the editorial commentary entitled, Autograft Beats Allograft for Most Knee Ligament Surgery, which was a commentary in reference to the paper entitled, Fibular Collateral Ligament Reconstruction Graft Options: Clinical and Radiographic Outcomes of Autograft Versus Allograft with the primary author being Travis Dekker and the senior author being Robert LaPrade. Both of those articles were published in the March 2021 edition of the Arthroscopy Journal. Dr. Levy, thank you for joining me today.

Bruce Levy:                         Thanks for having me on. It's a pleasure.

Clay Nuelle:                        Let's start with just a basic summary of the article and then a brief summary of your guys' editorial commentary in reference to the article itself.

Bruce Levy:                         Sure. Thanks, Clayton. Basically what the authors did is they performed a retrospective cohort study looking at FCL reconstruction using autograft compared to allograft in the setting of a very unique ligament combination. And that is with ACL and isolated FCL injuries. Not ACL posterolateral corner but ACL and isolated FCL. Just the FCL was reconstructed along with the ACL. And they did not have any of the posterolateral corners at all. And what they did is they determined that the indication to reconstruct the FCL was a side to side difference of greater or equal to two millimeters on bilateral varus stress radiographs. And then they also performed stress radiographs at six months after surgery and also looked at two year patient reported outcomes in the two groups. The age ranges were 18 to 55 years old, if I recall. And then we were asked to just write a commentary on the paper. And so with that, I can probably just lead into our assessment of the paper and how it contributes to the literature and some of the limitations. Would that be good?

Clay Nuelle:                        That'd be great.

Bruce Levy:                         Okay. For the ACL portion of the procedures, they used either patellar tendon autograft, or allograft and it was at the discretion of the surgeon which graft they used. And then for the FCL reconstruction, they used either semitendinosus autograft in 50 patients, which was the majority, compared to allograft using either semitendinosus or tibialis anterior allograft in 19 patients, so more than twice as many had autograft. And again, the surgeon decided what grafts to use. There's an inherent selection bias in the fact that patients weren't randomly selected to which graft they had, the surgeon selected which graft. And as a general rule, we use autograft tissue in younger patients and allograft tissue in older patients.

                                                There are quite a few other limitations to their study. They did not report on the status of the meniscus or cartilage at the time of surgery and the groups unfortunately were not matched for age, sex, BMI, activity level, sport, time to surgery and as I mentioned earlier, they weren't matched for the ACL or the FCL graph types. When you look at two year patient reported outcomes, the status of the cartilage may be the number one predictor of outcome, the status of the meniscus or meniscal treatment. When you have all of these confounding variables, it's very hard to tease out that it was the choice of FCL graft type alone that led to the outcomes. Another couple of little points is I found it interesting they had two year outcomes, but they didn't have two year varus stress views. And I think that's an important point, Clayton. Here's why.

                                                They did varus stress views at six months and found basically no difference between the autograft or the allograft on stress views. but LaPrade shown previously that the autografts actually stay stable. In other words, if they do stress views at six months and compare them at two years, there's no change. But that study's not been done with allografts and allografts can stretch out over time. They take much, much longer to integrate and there's plenty of basic science research to prove that either with MRI or other methods that bone integration takes longer. It can be very possible that the allografts at two years may not perform well at all. All we have is the six month stress views and I'd be really curious to have Rob redo that same population, that same cohort and stress them at two years and see if there's any difference.

Clay Nuelle:                        Do you think there would be a big difference?

Bruce Levy:                         I don't know if there would be a big difference, but I think there might be a small difference and that small difference may be what reaches significance.

Clay Nuelle:                        Do you think it would get back close to the two millimeters on stress radiographs for some of them?

Bruce Levy:                         Yeah, I think so. I think so and that's just what we've seen with allografts over time with our PCL reconstructions and Rob also presented his PCL data and the early data showed very little side to side difference, but at five years showed that the difference is a little bit more. And most of those were allografts. And so I think the allografts tend to stretch a little, I don't know if it's going to be a lot, but I think it'd be really interesting to see what happens at the two year mark.

                                                The other thing that sort of caught my eye is the indication for them to do the isolated FCL reconstruction was the two millimeter side to side difference. And Dave Fisher taught me years ago in fellowship that you can have a little increase in varus laxity from the ACL alone. And in fact, McDonald has shown that just sectioning the ACL can give you about a millimeter side to side difference on varus stress testing. And then Rob in his own sectioning study showed that isolated FCL sectioning can lead to up to 2.7 millimeters of side to side. You would expect that if the ACL was torn and the FCL, that it would be greater than 2.7, it'd be in the three range. It felt a little bit, are we sure we need the LCL done at two millimeters of side to side difference? And I don't know the answer to that.

                                                We do know that if you leave the LCL alone or the FCL alone, that it will put extra stress on your ACL graft. I don't really have an issue with the indications of two millimeter side to side, but I do think it's interesting that it wasn't much more. That they didn't notice a lot more side to side difference than the two millimeters.

Clay Nuelle:                        What percentage of patients, you have a really busy multi-lig knee practice as well certainly, obviously. What percentage of those are roughly, would you say that have a concurrent ACL and maybe a minor or major lateral sided injury, are you doing an ACL and isolated FCL reconstruction versus a modified or full posterolateral corner reconstruction?

Bruce Levy:                         Yeah. That's a great question. And it has to do with the wonderful work that Rob did on the sectioning study. If you have an isolated FCL, you would expect a side to side difference around that two and a half millimeters. And if you have an FCL with a posterolateral corner, you would expect it to be over four millimeters. We do intraoperative bilateral stress views on every single ACL multilayer, everything you can imagine. Not a routine ACL if it feels normal on exam, but any patient that has any side to side asymmetry on my exam, even an isolated ACL, I'll bring in fluoro and I'll do varus stress views and measure them. And the intraoperative fluoroscopy measurements, you can get quite precise. But we do have, I would say that this is a rare injury. The ACL isolated FCL, I have probably, I'm going to say in 22 years, best guess around 20, 25. ACL posterolateral corner I see way more often.

                                                I think that ACL, LC, FCL reconstructions are definitely more rare, but I think surgeons should be in tuned to it because we know if we neglect the FCL, that there's a higher risk of failure, stress on the graft of the ACL. I think everybody needs to be in tune. And I don't know a 100% that a two millimeter cutoff is enough for me to pull the trigger. But I think this paper really is excellent because it brings light the importance of assessing the FCL when you're doing an ACL reconstruction. And they found no difference, autograft or allografts, which means right now in 2021 it's dealer's choice. You want to pull out an allograft, no problem. You want to take a semi-T autograft, no problem. I think that really contributes. But for me, the biggest thing is that it makes surgeons think, I'd better check the LCL.

Clay Nuelle:                        Those are terrific points. Let's dive into the autograft versus allograft discussion a little bit because you guys discussed it a little bit in your commentary and you guys have published many papers on it yourselves, obviously there. And so what are your thoughts just in general when it comes to either isolated FCL or posterolateral corner, since maybe we're going to see more often doing reconstruction of the posterolateral corner concurrently with an ACL reconstruction. What are your thoughts in general and autograft versus allograft? And what's your algorithm? Does it depend somewhat on age or activity level of the patient or a combination of those things?

Bruce Levy:                         Yeah, so wonderful question. And I think that when it comes to multi-ligament knee surgery, if you're going to start doing a four ligament knee reconstruction with all autograft, you're asking for quite a lot of donor site morbidity. I think that it depends on how many ligaments you have to do, the age of the patient. If I have an ACL posterolateral corner in a high level collegiate athlete or a pro athlete, that's getting a patellar tendon autograft for the ACL and a semi-T plus or minus gracilis for the posterolateral corner, whether we do it with our technique, which is a single base graft or we do Rob's technique, which is a two two tailed graft. I'm using all autograft. My own personal experience is the autografts just perform better. They're just always a little bit tighter. We don't have patient reported outcomes to compare, but my own experience anecdotally, is that the autografts feel better, work better.

                                                And certainly now, I've got the bug to look back. We just don't have, I think, enough autos versus allos to compare. And the multi-ligs we do predominantly allograft because of the donor site morbidity when you're doing three and four ligament surgery. But if I have a pro athlete with ACL, medial and lateral side, then we'll do a BTB autograft, the lateral side, I'll probably do an allograft because I don't want to take anything that is a secondary stabilizer for the MCL so I won't take the hamstrings. And then for the MCL using the Achilles allograft, because in our series of 10 year followup, we've only had one failure. In 22 years, we've had one failure of an MCL allograft. I've been extremely happy with allograft for the medial side.

                                                And if I'm doing all four ligaments, honestly, even in a young athlete, I'll probably just go all allograft because I can get through the surgery much quicker. And I think in that setting, it'd be really hard to bear out that autograft is better. We did a systematic review on PCL based reconstructions and found no difference in allograft versus autograft on our systematic review. And for the PCL, with our technique, our technique requires a very long graft and so it'd be very hard to do our technique with autograft tissue so we use predominantly allograft for all the PCLs at this time.

Clay Nuelle:                        And your PCL technique, I think I've seen you present a number of times typically is a single bundled technique. I know this is a little bit of an offshoot from this study, but just since you mentioned it, correct?

Bruce Levy:                         Yes. Single bundle. And we did many years of double bundles too. I'll do a double bundle in the setting of a revision PCL, but for primaries we're all single bundle. And there was a systematic review that John Sekiya did years ago that showed no difference. Rob's got one that's more recent that shows a tiny difference in favor of the double bundle, not clinically relevant. And we published our five year data with our all inside technique. And we had 1.1 millimeter of side to side difference on kneeling stress views at one year. We've been very, very happy with that single bundle technique. And my mentor, I always say I'm a Fanelli disciple, but my mentor Greg Fanelli did actually a consecutive series of 90 PCLs, 45 single bundled compared to 45 double and on every single testing parameter you can imagine there was no difference. I think that debate is still ongoing.

Clay Nuelle:                        Absolutely. Those are terrific points. Just getting back to your commentary study, you guys mentioned that there may have been a little bit of selection bias and you kind of alluded to it in your example of how you treat certain people in terms of maybe a young athlete, you typically would try to prefer if an ACL and lateral sided injury to utilize autograft hamstring for the lateral side of reconstruction. In their particular study, typically some of the older patients got allograft and some of the younger patients got autografts. Do you think that there was probably maybe potentially a little bit of selection bias in regards to that? And if the younger patients got allograft, could you see some issues potentially there? Or do you think it might be okay still in the overall setting?

Bruce Levy:                         I think it's all okay. I don't think there was any significant differences, but there's no question there's huge selection bias and there was selection bias with the ACL graft. And so, who's to know what's the most important factor for good outcomes? Is it the ACL graft? Is it the FCL graft? Is it the meniscus? The cartilage? The age? None of these things were controlled. All these confounding variables really need to be controlled. If we really want to answer the question, what's the best graft type for FCL reconstruction in the setting of ACL, isolated FCL? Then we either need a randomized trial or you need a matched cohort that controls for all of those variables so that you can tease out the one thing you're looking at, which is autograft versus allograft for the FCL. The ACL would have to be the same. The groups would have to be matched demographically. They'd have to be the same amount of meniscus and cartilage lesions. All of those things would have to be accounted for, for you to tease out really what made the difference.

Clay Nuelle:                        Those are terrific points. Dr. Levy's commentary, Autograft Beats Allograft for Most Knee Ligament Surgery in reference to the paper entitled, Fibular Collateral Ligament Reconstruction Graft Options: Clinical and Radiographic Outcomes of Autograft Versus Allograft can be found in the March 2021 edition of the Arthroscopy Journal or online at arthroscopyjournal.org. Dr. Levy, thank you very much for joining me.

Bruce Levy:                         My pleasure. Thanks for having me on.

Clay Nuelle:                        That concludes this edition of the Arthroscopy Journal podcast. As always, if you enjoy the podcast, please remember to give us a five star review on your podcast device.

                                                The views expressed in this podcast do not necessarily represent the views of the Arthroscopy Association of North America or the Arthroscopy Journal.