So, you know, it's supposed to be an emerging technique discussion this morning, and so I'm going to hopefully show you something a little bit different, and we're going to talk about the role of internal bracing for ACL reconstruction, and I really want to talk about the biomechanics that we've worked on in the clinical application. This is my primary disclosure for arthritis, which does not really apply to anything I'm going to show you here necessarily. So what's my approach for internal bracing? Basically I want to show you where my background is in terms of looking at some of the studies we've done in canines first to show safety, and then we'll talk about some biomechanics, show you some new data, and then my clinical use. Just real quick, anybody routinely internal bracing their ACLs in the group here? Anybody? So maybe, certainly less than 10, so this may be another way to optimize your outcomes for ACL surgery. So my approach, I use fiber tape as internal brace. I really want to emphasize this is not an artificial ligament. We're not talking about LAD. We're not talking about LARS. This is a totally different thing. So fiber tape is unique. If you're a shoulder surgeon, you know many people use it in the shoulders. It's been used for a long time. It's got some unique properties. First of all, there is some dynamic elongation, and I'll show you this later as well. The fiber tape actually has creep in it. So when you load it up to 400 newtons, it actually lengthens. So it's important to understand it's not like a cable. It does have this relative creep to it. Biologically, this is a study on the right that Jimmy Cook did at Mizzou looking at placing synovial sites in culture and put in fiber tape. And so that green that you see are the synovial sites attaching to the fiber tape because it has kind of a weave to it, so it's almost biologic. And I've seen that going back on some second looks of ACLs where the fiber tape is kind of incorporated with the graft almost. So is it safe in the knee? This is the thing that I always get all the time, and Seth and I are in the ACL study group, and I've taken some heat over the years from the European colleagues that are pretty conservative saying you can't do this. We've been there before. History repeats itself. This is large. This is Gore-Tex. You're going to be a problem. And I would tell you that's not an issue, but we had to prove it. So we went to the canine model at Mizzou. We're fortunate with Dr. Cook there who's an orthopedic veterinary surgeon that has access to the animals, and we can work together. So the canine's a very sensitive model for any insult if you're going to do a study. So what we looked at is putting fiber tape in the dog knee, and so the way we did this is we put the fiber tape as the intramural across the ACL, didn't touch the ACL at all. We had six dogs, and in three of them, I actually cut the tape. I thought, okay, let's look at the worst-case scenario. I'm going to cut this tape, and let's see what happens. So we studied these animals out to six months, which is a long time in dog follow-up. That's a routine time to look at things, and we saw no articular cartilage changes, and we saw no problems with the synovitis from using the fiber tape in the canine even when it was cut. So I think this was an important safety study that we published a couple years ago. So as another translational study, the question was, would it work? So in the dog world, intraarticular ACL reconstruction is not done because it fails, and the reason it fails in animals, dogs particularly, because of the high tibial slope. It's usually greater than 30 degrees. That's why if your dog tears their ACL, they do an extraarticular procedure or they do a slope corrective osteotomy. So what we thought is, okay, what if we try to do internal bracing with an intraarticular ACL reconstruction of the dog, which would be the worst-case scenario, right? So what we did is this study. We had 10 dogs. We did an all-on-side technique with a quad tendon. So we took it from a different animal, so it was an allograft. And so you can see here, these are little animals, but you can do it. We did this technique where we did button fixation on the femur and tibia, just like an all-on-side that Clay talked about. But we added an internal brace in the animals. So we compared it to the normal side, studied them with x-ray. We did clinical exam on the dogs, force mat, I mean, all the great things that you can do at a high-level veterinary operation. But they were scoped at eight weeks and six months, and then sacrificed at six months. So what we found is that we compared to the other limb, we had really no clinical difference in the dog in terms of their gait and range of motion with the internal brace group. And here, our biomechanical results compared to the normal knee, stretching for stability was exactly the same, stiffness was the same as well. And we published this. So really, this is the only study that's been shown in the canine world where we actually did an ACL reconstruction intra-articulately, and it held up to six months, and that's not been reported before. And I think the internal brace is what we think probably helped us with that. So now if we talk about where we're at going from those translational canine studies in terms of how this works, the key, I believe, is that this is independently done. So the tape is passed, as you can see in this slide here, through the suspensory button. The graft is passed separately through the loop of the suspensory device. So you can see right there in the red circle, that's the key, is where that tape is passed through the button. So it gives us this independence between the graft and the tape, and I'm going to spend some time biomechanically to tell you that I really believe there is no stress shielding, which is one of the criticisms also that this technique is going to harm the graft because of that. I don't think we're going to be able to show you, especially with the new study we did, that that's not the case. So we call it a dynamic safety belt to protect your graft. It gives you higher failure loads and reduced elongation, which I'll show you from a biomechanical standpoint. And the other thing is it's simple to do, to add to your graft. Doesn't take any time. If it protects your graft, you know, for me, my interest is to have zero re-tears in my life for my ACLs procedures. You know, you're all good surgeons in the audience, and I think I can tell you that I don't care how good you are, your revision ACL is never going to be good as a good first primary. So if we can never have a revision, I think that's a goal we should strive for. So this is the first study that we published looking at the biomechanics. And what we're looking at here is putting a tape in and where it does biomechanically into basically a stress-strain curve. It's on the right. In this particular, I'll show you a little bit more in a second, but there's a cone where it says ACL. That's based on normal data that's been published of where the ACL should live in a hysteresis curve. This just shows what happens when you have an internally braced graft versus not having one. So this is that function zone curve that we basically looked at the literature from these multiple studies, figured out, okay, this is the normal hysteresis curve, kind of this cone for the ACL. So we studied it first in this setup where we used porcine tibias, and we fixed the graft. You can see that the tibia is in the bone, and then we have this technique where there's an acrylic block, and we pass our button up on the top. And what we looked at is a tripled graft, a relatively weak graft at 8 millimeters diameter versus a quadrupled graft that was 9 millimeters. So it's a weak versus a strong graft, essentially. And then on the far right, you can see we also looked at the suture tape alone. We tested that alone. We did a very rigorous testing model, which is not typically done. We did 1,000 cycles at a postoperative range of motion load, then we did 1,000 cycles at 250 newtons, and then 1,000 cycles at 400 newtons, which is a high rehab load. So we really stressed these grafts to see what the effect would be. Here's the small 8 millimeter graft. You can see on the blue is where the tape has been placed in the grafts, where it shifted the displacement. So if you look at 250, you can see the, I don't think there's a pointer on here to show this very well, but maybe I can show it. So here's the zone, the ACL function zone. So this right here, the black curve is 250 for the small graft and 400. You can see the displacement on the right. So in this model, there was a lot of displacement. We added the internal brace, it kicked it into the zone. What I really want to show you too right here, this is fiber tape alone here and here. So look at the displacement of fiber tape. It's what I told you earlier. It does have this displaceability. So what we found here is it was 51% improvement at 400 newtons by adding the IB for the small graft. So we went to the standard graft. The other question was, okay, if we have a good enough graft by diameter, are we going to make things too tight? So here in our model, you can see at 250, the regular graft was in the zone, okay, but look at a 400 newtons, it was out of the zone. We kicked into the zone perfectly though with the fiber tape. And again, look at the laxity of the suture tape alone. So what you see here, it's kind of thinking about this, okay, I'm showing you the grafts are loose in this model without the tape, but the tape also shows some relative elongation as well. So how does this work? So in this one, we just had the improvement was a bit less at 26% with the standard graft. So really this is a synergistic load sharing concept here. So this is our model. You can see how the graft here, it loosens when the knees flex, tightens at extension. So that's the cycling that we did. But what's happening is that the low loads, the graft sees the load, that the higher load, the tape kicks in. Remember, they're both a little bit lax without the tape, but working together, you get this synergistic response, so we don't have any stress shielding. So what about using with an internal brace with a BTB? We published this as well, looking at what happens. We looked at screw versus screw fixation versus an ALD for the BTB versus ALD plus an IB. What we found here is that there was a 31% improvement in our cyclic displacement by adding the internal brace to the pterotendin graft, and our ultimate load was 45% better. So in this model, what we've done here is that we have an adjustable loop device on the femur. Here's our internal brace here, and we'll fix it here with an anchor, and then we fix the graft on top of it. That was our model that we do, which is what I do clinically if I do a BTB. This study is not yet published, but it's in press. Came out of St. Louis looking at the same idea of putting an internal brace in a pterotendin graft. They used porcine knees and did a BTB reconstruction. Although they didn't find any difference in cyclic displacement with the internal brace, they found 104% higher post-cyclic stiffness by adding the internal brace to the augmented group, and the mean ultimate failure load was 50% higher with the internal brace group. Their conclusion was this could be protective for BTB grafts. Again, this will be coming out soon in arthroscopy. So what I want to share with you this morning that is new data. This is the latest study that we have that's been submitted where, again, because of this concept of stress shielding, we felt we needed to take it one more step. And so this particular study is using optical tracking. So you have an optical tracking here. Let me back up for just a second. So here's our optical tractor, and what we're going to look at is, again, the weak graft, the three-stranded graft in this model here, which was 7 millimeters, and then we added a tape to it here, and then we looked at versus a 9-millimeter graft. So what we were looking at now is when does the tape kick in? So if you look, here's our model. These are our tracking device here, but what we're showing is the tape, when we put the tape in these knees, we put it in slack. And so what we were interested in is when does it kick in? When does the tape, at what point is there a transition zone to where as you load the graft, what's seeing the load? Is it the graft or is it the tape? So we added the optical tracking as another step to show this. So all the grafts underwent position loading first, and the way we do this with the Instron machine is basically we fix it at 30 degrees of flexion, but then we control the range of the distance intra-articular, which is how we get the laxity of putting the tape in at full extension, although the graft is fixed at 30. So that allows us to have the tape a millimeter slack when we do it. And so then the retention, we go through 1,000 cycles again up to 400 newtons. So not to get too complicated here, and I'm not a biomechanist, I'm a clinician, but I do get involved in this stuff here, and basically this is our hysteresis curve and our peak in a valley, and you can see what we're looking at is what point does that tape get tight? That means the tape is kicking in and seeing load. You can see here they're both on the Instron machine together, and this is our curve, and right at this point here, this is the transition zone where the tape kicks in in light blue. So looking at it again, this is a normal curve here at 100 newtons with our hysteresis curve. You can see there's no tape at the low load. Only when we hit 200 newtons, you start to see a little bit of blue. This is the transition point where the tape is starting to kick in in this model, and you can see as you go into higher loads with more elongation, the tape kicks in further. So this is probably the best slide to kind of summarize it so you can see exactly what I'm talking about. At the low loads, this is the 7mm graft here, and this is the 9mm graft here. So the blue is the internal brace load, the red is the graft load. So at the low loads, you can see that the graft is seeing all the load. It kicks in at about 200 newtons here for the low level, the smaller graft, and as you get into higher loads, then the tape kicks in so it's a higher load is where that tape really does its job with the bigger Heart the larger diameter graph nine millimeters you can see here. It doesn't kick into about 300 newtons So if you have a bigger stronger graft It's seeing the load until you get to that higher load than the tape kicks in So this really proves that there is not a stress shielding phenomenon. The graft is seeing load So In terms of the key findings the load sharing starts at lower loads about 200 for the 7-millimeter graphs and about 31% of the total load is applied to the tape at the load sharing is higher 300 newtons for the bigger graph the larger Diamond I remember graphs that it's about only a 20% though That's carried by the IB so the majority of the load is carried by the graft in our model So the peak load sharing with that independent suture tape independent passing the tape through the button Resulted in decreased in elongation in these graphs because it increases the stiffness But again, it's a function of occurring at the higher load that happens and this is that dynamic Concept this is suture tape alone. And again, I want you to see this is the hysteresis curve for suture tape again You can see that the the peak versus the valley, you know You have three to four millimeters of less relatively elasticity or elongation in the tape So the tape gives and I think that's really critical in our clinical practice when we do these graphs and I add the tape to them that it's not going to over constrain the joint and Finally, this is just the last slide you're showing this last study We've done how when we add the tape we get into this augmented range of appropriate ACL function zone without it You have this elongation and your graph stretches out. So again the idea of the suture tape to protect your graft So, you know, where are we at now, so I try to set the table, you know show that it's safe We've done the canine studies biomechanically We've done a couple of studies now to show that it looks like it should be effective By transferring the loads again at the higher loads to protect the graft and where will this help you clinically? Well, I think it may help that ligamentation process that we talked about earlier So when your graft is really weak phase if a patient gets too active too soon You have some confidence that your graft is protected. Hopefully won't stretch out And I think the other thing is a later protection of the graft to avoid retears as we talked about which I think is critical So we all have our high-risk patients have been talked about this morning with CESC, you know Great talk wood graft to use under the 18, especially the female soccer players and the cutting sports Revisions, so these are areas maybe if you haven't used a suture tape to start thinking about maybe you start with that and see how you like it and what I will tell you is the way I do it I've been doing a long time if you fix these and Full extension, which is how I fix the tape and I'll show you clinically the tape in my practice I always fix first and the graft is fixated second. So what you'll find though is the normal ACL Has three motors of laxity as you go from full extension to 90 degrees of flexion So when you do this in a clinical case what you're going to find is your tape at 90 degrees you put your probe on It it's going to be loose inflection. It's tight and extension loose inflection And I think that's really a critical point about doing this clinically So I think potentially this could be a paradigm shift for us again to avoid this risk of retear Remember if you're going to do this all of our work that we've done is all about independence of the tape and the grafts So that tape is passed through the through these fixation suspension button. The graft is passed through the loop So I think from a standpoint of ACL revisions We all know ACL revisions have a high rate of retears So if we can improve our clinical outcomes If you have a smaller graft if you have a small hamstring graft a smaller patient And you don't want to add an allograft to it, which has shown really not to make a difference Adding a suture tape I think is a great way to support these grafts again The work we've done biomechanically would suggest that as well if you're an allograft person and a young patient You know craig batani showed that high risk of failure young people with allografts Seth talked about it wanted to add a tape there's another option here and again just our high-risk patients You know, I sleep better at night You know all those patients that you know We tell them to go slow and you know They're out playing basketball at three months in the backyard and so I think that you know this extra security of having the tape for me to Makes me sleep better at night knowing those grafts are protected So again, I fix these always in full extension or if the patient has hyper extension the way I do it Is my assistant holds the heel and we pass our Our tapes through our fixation button on the tibia. It's an all inside technique that I do Our tapes through our fixation button on the tibia It's an all inside technique that I do And then we hold it in fully hyper extension and I fixed the tape first with a little anchor After I fix the tape then I tension my graft on the tibia So again I think it's really critical. I fix the tape first people say why do you do that? Well, I want to make sure that the last thing that sees load on that knee is the graft So tape is fixed full extension. Then you'll see what I do. I Cycle the knee and then i'll fix the graft with uh with the knee again in full extension or hyper extension But you know, this is what I do intraoperatively and and I take let the fellows play with it You know do a drawer do a pivot whatever you want to do This is another huge advantage in my opinion of the all inside technique and then we retention So you eliminate any potential creep in the system right here? By doing your cycling vigorous cycling and then retention the femur and the tibia with the all inside technique But again, the tape's already been fixed. So the graft is the last thing to see load based on my methodology in the operating room So again, I showed this earlier But you'll always be able to see this the tape will be loose inflection when you fix it in full extension You're not going to over constrain. I've really i've never seen a tape Tight inflection it doesn't happen because again the normal biomechanics is the acl loosens from full extension 90 degrees of flexion So you're automatically protective you're not going to over constrain by fixing them when as long as you fix that tape in full extension So where am I at clinically at this time? Um, this slide is is is not quite totally current We're up to almost about 400 now But the number of patients that i've done i've done and this is an outcome-based system that I follow these patients on called surgical outcome system, so I Really keep track of my patients here to make sure we're not getting into issues So i've got 340 for my patients on my on this registry right now You can see btb. I do have 84 I do less btb now and we can talk about that based on that study that I did Hamstring versus btb, but in this study, we've got 110 quad 63 hamstring some allografts and 46 revisions so so far in terms of of Revisions of somebody with a tape in this in my practice I've had one it was an allograft case that a guy fell two years post-op and and ruptured his graft The tape was not ruptured. It was just kind of loose Looking at my registry data though. Just looking at my two-year outcomes In this particular registry you can compare yourself to other surgeons around the world on the registry And basically just looking now these aren't this isn't statistically significant just it's a trend but my tegner scores are in yellow Which are a little bit higher And and also you can see my ikd subjective so at least i'm In the range, I don't have outcomes that are looking much different than other patients that have been reported with standard acl surgery But again for me the goal was to avoid revisions So this study we're just getting the final data to get this published So we've looked at some bring two-year follow-ups and bringing people back average age of 21 We've had 46 back in the clinic now. You can see our breakdown btb hamstring quad pretty equal I've had two of these patients that have come back that have talked to have told us they've had a re-injury And i'll show you one in a second. None of this group had a revision Which I think is important the two that had the re-injury when we kt tested everybody They were all under two millimeters with these two patients. One was four millimeters on kt. The other was five Both of those patients had been previously studied at one year with a kt. That was one millimeter or equal So they definitely something happened from the one-year follow-up till we brought them back after this two-year follow-up But i'll tell you that those two patients did not have a pivot in the clinic Now one I ended up actually operating on which i'm going to show you in a second the other I did not So nobody's had a revision in this group that we're bringing back We're trying to get 50. Covid kind of killed us getting people back last year to get this done But we mri'd everybody and all but two mris looked great two mris that weren't great were these two patients that had this re-injury So those are the people that we need to talk about So this is one of my cases. This was an 18 year old male. I did a quad tendon graft on And he called me he said doc something happened to my knee four months out He stepped in a hole comes to the clinics got a huge swollen knee. So i'm thinking okay, you blew your graft This is awful. So i'm hoping the tape wouldn't let you do that So I drained his knee about 90 cc's of blood and I examined him And really he didn't have a pivot and didn't have much of a lockman. I did a kt. It was only a millimeter So i'm thinking what the heck, you know, I did an mri Um, and you know mris aren't perfect at four months Anyways, but you know, it doesn't look that great all inside technique You can see like the potted plant, but it didn't look that ideal so said I think we need a scopia and maybe have to do a revision here because this young man's a real active guy and Wants to be a policeman. So We put the scope in and um, you know first examining under anesthesia. He did not have a pivot um, I had a fellow with me at the time who was uh, Um a little skeptical should I say of internal bracing so she Wanted to show that this patient had a pivot shift and after about five minutes. I told her there's no pivot you can stop now Um, and so we put the scope in and here's what we found interestingly enough You can see here. There's some definite retear of the graft. Obviously. This is a fresh retear But if you look really closely here's this little blue structure here That's a little bit loose and that's the suture tape That clearly is loose and the question is did this save this kid's graft? You know, I did not revise him This is he's almost a year and a half out now. He's a policeman in quincy, illinois Um doesn't wear a brace and functions fine So, you know, maybe maybe this is kind of the real world meeting the biomechanics and the science But this patient did not have a revision and maybe maybe the tape saved him So what's been reported in the literature on suture tape augmentation for acl not a whole lot This was the first study that was published out of washington. Evan argentar was the senior lead author in this study It was retrospective so it's a little it's not a prospective study and they looked at 30 patients with internal bracing And 30 without now they had allografts and autographs. So it's kind of a mixed bag a little bit Interestingly, they reported actually better patient reported outcomes with tape Higher in early return to pre-activity in sport level with a tape So in this particular study, they made it sound like the tape was a super acl that people got back quicker And they were did better now they had a 6.7 percent retail rate in both groups Which i've not seen with tape the retail rate that's not been my experience But also i'm here to tell you my experience is not That patients with the tape have like a super acl that they go back quicker And so although this study reported that I personally have not seen that in in in my case Case is almost 400 that we've done now So this was just a recent study published from the mayo clinic And this was a cohort study where what they did is they looked at Patients that had a tape which was 35 36 rather and then they looked at a case controlled series of patients that they had done years previous Without a tape. So it's again. It's not a really a matched pair necessarily They didn't see any difference in complications in terms of graft failures return to sport Or their ikdc or leash home interestingly, though The suture tape patients had higher post-operative tegner activity scores So maybe it helped them in the activity standpoint at least didn't show any particular problems adding the tape So I think in kind of wrapping this up, you know how to do this just seemed simple here as we talked about you pass That tape independent with the button you fix it on the femoral side You pass your graft in usual fashion fix the tip as you can fix the tape first full extension Cycle the knee And then you can retention So that's a technique again summarizing it use in clinical practice Easy to use it doesn't change anything. It's quick inexpensive relatively to add the tape. It's fast And it's reproducible. I think and again, there's ideas of small grafts revisions or those high-risk patients to help you sleep better at night It's not an artificial ligament. I think we can safely say that Um, you know, I know i'm not the only one that uses the tape but you know We're trying to get our data out there But I think what I really try to emphasize is that I set the table when I talk to my patients I tell them listen, you know i've studied this we've done canine studies. We've shown it's safe We've done biomechanical studies to show the efficacy that should work and and now i've done it clinically in almost 400 patients So and the importance is passing that tape independent of the graft as I showed This concept of the seat belt the tape kicks in at the higher loads to protect your grafts So there's no stress shielding. Our last study is confirming. It's a load sharing concept And again for me i'm hoping that we protect from re-tears and the data so far is looking very promising Um, you know, i'm not perfect I'd very much like to not have any re-injuries if I could so I think this is potentially one way that you may help Your patients adding a tape and and avoid future problems after their ACL reconstruction Thank you

surgeon

internal bracing

ACL reconstruction

fiber tape

biomechanical findings

clinical experience