Thanks very much, Jim, and Craig, and everyone, Gee, who's put this program together between the AOSSM and NFLPS. Certainly an honor to be here. Always difficult to follow Mike Salata's eloquent talk. He also has the head of hair that I've always wanted in life. In terms of talking about revision ACL reconstruction, how do you manage the recurrent ACL graft tear? And I do think it's very appropriate to mention that so many of the team physicians that are in this room and some who aren't have taught us so much about this area, so I want to acknowledge all of their contributions. I think one thing that's important to recognize when you look at revision surgery in general, but of course it's appropriate and applies to ACL reconstruction, is things done the second time around never do as well as the first time around. This is a large series that's been done from the MARS cohort from Rick Wright and their group. And you can draw your attention here that whether you look at PROs such as IKDC scores or you look at objective failure rates, revision ACL reconstruction has three to four times the rate of failure compared to primary ACLs across the general population. And this has been repeatedly published in the literature. This is a large series, again, from the MARS group, 863 patients in 21 studies, graft failure rate of 14%, and Lysholm and IKDC scores that would certainly be modest for us in the setting of a primary ACL reconstruction. Now what of course makes this challenging is while we know these objective outcomes, when you're dealing with a revision ACL reconstruction, the attention is often on the graft failure, but it comes with these associated concomitant issues. Mike just spoke on this very nicely. Often with revision ACL reconstruction, the incidence of high-grade three or four chondral defects affecting the weight-bearing condyles or patellofemoral joint are quite common, as high as 80%, at least grade one to two changes. And as Pat Smith eloquently talked earlier, more of these complicated meniscus tear patterns that of course place a cult strain on your ACL graft in the revision setting. What even makes this more challenging, and I think every athletic trainer and physician in this room appreciates this, is there's a gap between patient expectation, particularly the high-level athlete, and in fact these outcomes. There is this perception if you look across this survey study that 84% think they're going to get back to the same level of activity, 94% don't expect any instability, they don't really necessarily appreciate this higher risk for osteoarthritis. And so there's this concept that this is much like opening the hood of the car and replacing the oil again or replacing a spark plug, but not this recognition of the occult quad atrophy and all the issues that go on with multiple surgical procedures. So it's incumbent on us to bridge this gap between expectation and what's been clearly published in terms of objective outcomes after revision ACL surgery. So how do we approach this in this population, whether it's the high school athlete or your professional NFL athlete? I think this is the set of order or cadence of steps that we should take, and I'll just draw attention to the fact that what sits on the bottom of the list is technical failure. We tend to jump there because that's the area we can improve on. The prior surgeon didn't make good sockets. The tunnel was too vertical. But we should in fact step back and look at all of the questions before that, including potential occult instability. Could it be a biologic failure? Could it be a graft issue? And then of course, always when you're doing a revision surgery, take advantage of your opportunity to learn from history and look into prevention. So let's start with history, and again, this is great work that actually has been published by Mike Stewart and Aaron Critch out of the Mayo Clinic, which is you think, well, what history do we really need here? The graft retore. There is a real importance to this about pain versus instability. If they're having pain, it may be more what Mike spoke about just earlier. It's the chondral injury, meniscal injury issues that are now the predominant source of concern for them, even with perhaps a slightly stretched but functionally intact graft. On the other hand, we also need to think about mechanism. And so things like this. My knee has been swollen for a while, and now I had this occult injury or this new traumatic injury, or my knee has never felt right since my original surgery. Those histories will point to some initial issue either with biologic incorporation or functional instability of the graft versus my knees felt great for two seasons, I haven't had an issue, and then I had this one traumatic event in terms of distinguishing biologic and traumatic failure. What about physical exam? In our busy practices, this becomes more and more challenging to do thoroughly, but pay attention to simple things. If you see a varus thrust during the gait, if you see recurvotum or hyperextension, as Mike just pointed out, things like double varus or triple varus are going to predispose any well-done revision ACL to failure. Always examine the other knee for things like recurvotum, a high Baten score, and hyperlaxity. And you need to, even in the clinic, be able to perform somewhat of a pivot shift examination on an awake patient to get a sense of that functional instability. So where can we learn from this? Good studies that point out what's going to be a greater risk factor when you're doing your revision ACL, hyperextension, and a high-grade pivot shift. So if the knee has greater than 5 degrees of hyperextension or a grade 2 plus pivot shift exam, whether it's your primary or revision ACL, higher failure rate been published over and over again. I had the privilege of doing this with Chris Larson, the Minnesota Vikings physician and a colleague of mine, where we looked at our ACLs and revision ACLs, and no surprise, 25% failure rate after primary ACL in the hypermobile group compared to the non-hypermobile group defined by a Baten score greater than 6. Similarly, what we found was things like heel-to-table height, which is a surrogate for hyperextension, significantly higher failure rate. And that's been corroborated in the literature over and over again. This study by Halito pointing out that just 5 degrees of hyperextension is going to increase your revision and primary ACL reconstruction failure rate. So little amounts of hyperextension should make you think about an LET at the time of a revision ACL reconstruction, or at least being aware of that possibility. What else about physical examination, things that patients can show you? This, of course, is your pivot shift examination. This is Charlie Brown's video he kindly shared with me of a grade 3 pivot shift in the absence of any occult findings of instability, meaning no posterolateral corner. But you can see sometimes occult capsular injury or quote-unquote ALL injury can give you these high-grade pivots. If you see this at the time of your surgery, you need to be thinking about a higher failure rate risk. What about patients like this? This actually happens to be a patient of mine who'd had a prior primary ACL. He's an offensive lineman. He comes into the clinic and shows you that dynamic exam, I can make my knee shift. Of course, when you look at the imaging occult posterolateral corner injury, that's not been addressed and he has this dynamic rotary instability. Stress radiographs have become more and more common, somewhat difficult to perform in the clinic because they're inconvenient, but they can offer a lot of value. If you are worried about lateral or posterolateral corner injury or MCL injury, a stress radiograph and measuring asymmetry between sides can be helpful. Rob LaPrade has helped to publish some numbers based on cadaveric work that 2.2 millimeters of asymmetry and 2.9 millimeters of asymmetry can help us to identify isolated LCL and then associated LCL and corner injury. Single leg stance can also help you to visualize posterior slope and anterior tibial translation. Alfred Mansour and Walt Lowe have taught us about this recently of the value of the full-length radiograph to be more accurate in measuring tibial slope. Mike already covered this, so I'll just point out again, making sure that you don't miss occult malalignment. It's easy to ignore this and say, well, this is the high-level athlete. We're not going to do an osteotomy in this patient. But when it's grossly asymmetric like this, no revision ACL reconstruction will fare well without addressing this in some fashion. Again, tibial slope covered by Mike, but again, it probably sees us more than we see it. Again, when you have a revision ACL reconstruction, pay more attention to this. Studies have now published that greater than 12 degrees is a high risk for recurrent failure. When you see a situation like this, increased slope, reasonably well-placed tunnels, don't just assume your new tunnels are going to solve this problem. This may be the situation for an osteotomy. This is good work done by Zafignini Abroad, who's published a lot in the ACL literature. He actually did this study looking at primary ACL reconstructions with a lateralplasty, aka an LET procedure, and which group tore or re-tore. Interestingly, when you look at the typical normal distribution of tibial slope, whether on the central measurement, anterior or posterior measurement, and then you look at the revision ACL reconstruction population, you see this shift in the curve, if you will. It's no longer a normal shape distribution. The re-tears are happening more in the greater than 14 degree slope population, including even their contralateral knee being at risk for an ACL tear. So this slope issue is a real one. How we manage it in terms of a slope-changing osteotomy in a professional athlete, still unsolved. Again, just some data to point this out in the revision setting, a recently well-done study out of a group in Turkey, where they looked at 350 males with primary ACL reconstructions and compared their morphology to non-ACL matched controls. And again, these typical findings. They have increased tibial slope. They have an abnormal condylar dimension, a so-called tomahawk ratio between the depth and the height of the lateral femoral condyle. Why is this important? Because all of these factors are probably seeing us in the revision setting, but if we don't measure and look for them, we'll miss them and simply perform the same procedure. Pat Smith showed this very nicely earlier. You can't think of the meniscus lesion as just an issue related to cartilage and weight bearing. As he pointed out, these are a source of occult instability. So when you see these complex root tears or so-called P-mort or L-mort type tears, which are root variant tears and radial tears, repairing them is as important for the stability in the revision ACL reconstruction as it is for the repair. This is a published image that actually is a useful one from Bertrand Sonnery-Cote, pointing out this difference between letter A, which is the typical ACL tear we see, and letter B, which has all of these occult risk factors, a ramp lesion, increased tibial slope, this abnormal tomahawk ratio between the height and depth of the condyle. This is your worst-case scenario where simply doing a revision ACL with anatomic tunnels is unlikely to work. This I can go through quickly because Mike already showed this. In these situations, this happens to be a revision ACL where performing a slope-changing osteotomy and realigning is important. Using a larger graft with quad tendon autograft may be valuable. And this can be done in high-level athletes, and I think we'll be seeing this more and more in these scenarios of second- and third-time retears. Finally, this concept of double and triple varus is not to be forgotten from Frank Noyes. Double varus, of course, with occult PLC and lateral-sided injury. Triple varus with the associated malalignment. This is a need doomed to fail unless we address these malalignment issues. Simply revising the tunnel or revising the graft will be insufficient in these scenarios. Again, very briefly, already covered very nicely by Kyle earlier, just pay attention to the lateral and posterolateral side. You can have occult injuries to these areas and end up treating an ACL in isolation. But simple injury even to an isolated LCL or even an isolated popliteus injury is one that you may pay attention to more commonly in the revision setting. Don't forget the medial side. It's easy for us to treat MCL tears and say, well, the MCL will heal up nonoperatively. Well, no two MCLs are alike. Some are superficial MCL injuries in isolation, stent or lesions as Kyle showed. But oftentimes it can involve the posteromedial corner, including the posteromedial capsule, the oblique popliteal ligament, semimembranosus insertions. Those are more dynamic rotary issues, very similar to PLRI. And Kurt Jacobson and others have published about missing occult posteromedial corner injury and failure after revision ACL reconstruction. This is great work we don't want to forget done by Steve O'Brien and the group at HSS. Whereas you can see here when you leave an occult medial-sided injury, of course the secondary strain in your ACL, native ACL or graft is going to go up as it becomes a secondary stabilizer to varus or valgus stress. And of course this has been repeatedly published by Markoff and others that when you have occult injury to your collaterals, the laxity is increased and of course the strain in your graft is increased. This is just this concept of a ramp lesion. This is a nice video showing it here. This looks like your simple, quote unquote, red, red zone meniscus tear. But you can see this is a meniscal capsular injury that's resting just proximal to the semimembranosus insertion. Here when you look with the scope in Gilquist interval and apply that rotary moment to the knee, you can see how the tibia actually subluxes through that ramp lesion. So to me, it's not a meniscal injury, but it's a sign of occult posteromedial corner injury that if you don't address at the time of your revision, ACL will be trouble. Finally, advanced imaging. Pay attention here to tunnel widening. Tunnel widening is a significant concern. Mike showed very nicely a case that he and James did where just revising this in an isolated fashion is unlikely to work. Have a low threshold to graft in these scenarios. You only have one more chance to get it right, particularly for a high-level athlete. If the tunnels are widened, staging them for the incremental benefit of anatomic tunnels is viable. Finally, I'll finish up here by the general algorithm. When you do finally get down to the technical issues here, the best case scenario for your revision ACL is really bad tunnels the first time around, right. You can just drill around them and put in anatomic tunnels. That's of course oftentimes not the case. These are the more common scenarios where, for example, here you have a tibial tunnel that's in a reasonable location, but it's widened. You can drill a new femoral tunnel, but you still have to manage the tibial tunnel. Situations here where these are well positioned, but they're enlarged and widened, again the grafting scenario. Now here you have some early arthrosis, but some collateral ligament laxity. Then finally the setting of arthrosis that's already developed after your prior ACL. This is where osteotomies become part of your concern. As has already been mentioned earlier, you can single stage, but have a low threshold to two stage when needed. If the tunnels are wide, people will talk about stacking screws or match stick techniques with bone dowels. Generally speaking, those have done okay in the literature, but I don't think any of us would want to rely on those in your high-level athlete. Graft it and take the additional time. Finally have versatility in your socket preparation. You might have to make these independently. If your first socket was drilled through a medial portal approach, you may have to do an outside-in approach in the revision setting. Finally graft choice matters. Autographs do better than allografts. That's a repetitive theme. We tend to have more liberal use of allografts in the revision setting. That may be reasonable, but again, if you have the opportunity for a quadriceps autograft to fill a large defect, that's probably a reasonable consideration. Finally I'll finish up by mentioning, does LET make a difference? I have to mention that to be thorough in revision ACL reconstruction. Al Getgood's stability trial has pointed out that LETs matter. When they look at all of these outcomes in a large multicenter trial, even in primary ACL reconstruction, it did reduce the asymmetric pivot shift and the failure rate of the graft. And so they concluded that adding an LET made sense to reduce graft re-rupture. It also decreased the asymmetry in the pivot shift. And so of course in revision ACL reconstruction, this makes a lot of sense. So in summary, high slope, occult ramp lesions, an elevated Baton score, hyperextension, and associated medial meniscus tears are all considerations for lateral extra-articular augmentation. And I think you'll see this more commonly in your pro-NFL athlete as we're seeing more and more concern of revision reconstruction and failure. Thank you. �

revision ACL reconstruction

failure rates

chondral defects

meniscus tears

occult instability