Welcome, everybody, to the Multi-Institutional Sports Medicine Fellows Conference. Thank you all for joining us. I'm going to ask you again to try to keep your microphones muted, though now that I have some better control of this thing, I'm able to mute you guys mostly, but this is being recorded, and this will be transferred to the AOSSM Learning Management System next week. So if you want to hear this again or tell your friends if they want to hear it, it'll be in a repository with the AOSSM in their Learning Management System. Again, we'll have hopefully some participation by faculty commenting and asking questions, but also, again, this is all about the fellows, so really want the fellows to ask questions and contribute, and what might be easiest is to actually just have you put that on the chat portion of the chat portion, and then I can read it, and Dr. Sherman, our guest speaker today, will answer, and again, maybe we'll have some contribution from some of the other faculty as they wish to participate. It is very much my honor to introduce our next speaker, Seth Sherman, as he joined us here at Stanford in August, so we're very excited to have him here. He's going to be taking over running the fellowship from me. He's an associate professor. He's a team physician, a head team physician for the Stanford football team, and he likes to cut bones a lot, so as opposed to cutting tendons like Latul likes to, and so without further ado, we'll have Dr. Sherman talk to us about all the uses of the tibial tubercle osteotomy. So, Seth, take it away. Thanks, Mark. You hear me? Oh, yeah. Excellent. It's a great opportunity. I'm extremely passionate about the patellofemoral joint and this topic in particular. Hopefully, we can drum up some controversy and discussion. My disclosures are in the Academy site. I think like many others, this talk and my entire experience is founded on some of the greats in our field, so John Fulkerson and many others, and from the past two days, I now have David and Latul up there on my wall of fame, just some outstanding lectures. This will be a bit different, but hopefully can round out our experience in patellofemoral. So, the age-old question here is really what's the best way to treat patellofemoral problems, and luckily, I have a guy next door, social distancing in the next office over, who says really refer to someone else, so I'm happy to be here and take all of these referrals, but I think that the truth is that patellofemoral joint preservation has become a hot topic. We've had some excellent courses over the last few years and a lot of interest from the fellows, and so it's a really exciting time to be involved, and way more questions than answers. I'm learning so much more than I teach every time that we address these topics, so we've heard a lot about instability the last two days, and that's going to be an important subset of my talk, but really want to pivot to talking about joint homeostasis, treating the PF joint as an organ, and also really covering things that we didn't talk about, pain and or chondrosis that comes from malalignment, and so hopefully that will add more to the discussion. Just like the other talks, I won't dwell on this, but we have to really focus on anatomy and biomechanics in the PF joint. We have to become masters of assessing this and assessing it relatively systematically and quickly. Jack Farr and I have written this that you all can have access to, but really when we go through the columns, we look at each of these factors in every single patient. I think Latul and Dave Deduck mentioned many of the same things, so we're always assessing patients' dynamic function. We're assessing for laxity or hyperlaxity. We're looking at their seated tracking for increased patella height, J signs, lateralized force vectors like you see here. We're looking for outliers of valgus or version that may skew us into a different treatment pathway. We're accurately measuring these alignment parameters, and we understand what the relative threshold values are, but I would caution you all to take these thresholds with a grain of salt. We can't make decisions just based on one metric or just based on metrics alone. We have to treat the patient. That said, we do need to communicate and think together, and so we have a common set of things that we use to measure. Coronal alignment, typically using a mechanical axis view, standing radiograph. Axial alignment, I always like to get two different measures and see the concordance or discord, so usually using TTTG as David went over. I also use TTPCL, typically using from MRI, but you can use from CT, and then sagittal we also went over Catan-de-Champ and patellotrochlear index, two very valuable indices that I use every day. When we're talking about TTOs and what can we accomplish, we can correct malalignment in the setting of instability, chondrosis, or combination of problems that we see here in the clinic. This is an infographic Jack Farr and I put together a couple of months ago. It's in arthroscopy. While it's a simplification, I think it can be helpful, and you can refer to it and I will refer to it throughout this talk as we tease out when we may use TTO for pain and cartilage and for instability. First, unfortunately, we need a little biomechanics refresher course. We created an in vivo model of gait and of the PF joint while I was at Mizzou, and what's nice about it is that we have a normal state. We can manipulate this normal state. For example, putting in a TTTG of 20, and what we see is that we create this lateralized vector, but it overloads distal and lateral cartilage, as you can see on the right there. When John Fulkerson came up with this intermedialization, this was able to shift those forces proximal and medial and normalize the joint forces when there's maltracking. What we see with medialization versus intermedialization really has to do with the slope of the cut or the angle of the guide. So a medialization, which is really called an Elmsley triot, is where your hand is parallel to the floor. This is to correct that lateralized force vector and had been used significantly in the past for instability, whereas really when we're talking about unloading the patella femoral joint, we're talking about adding differing degrees of enterization to our medialization. The steeper the slope, the more enterization, the less medialization, and what we've learned from Brian Cole's papers and others is that enterization equates to decreasing these joint reaction forces, and so we can use combinations of osteotomy to effectively get the job done in different situations. David Deduck talked about patella alta as it pertained to patella engagement, and that's critically important for us as well, but what we have to realize also as it pertains to joint loading and forces. When you have patella alta, you can see those forces are quite distal on the patella. When we do a distalization, we normalize those forces, getting back to a more distributed contact area and pressure, as you see in the map to the right. Patella baja mostly is an iatrogenic problem. The Katanda Champa is less than one. Patients may have difficulty with flexion, significant pain, and you can see those forces go up substantially and proximally. Similarly, when we correct this with proximalization osteotomy, we can normalize those forces and normalize that CD ratio. So when we're talking about indications for osteotomy in patella instability, I will also agree with Latul that an isolated medialization for instability is a rare actor. We must get out of the train of thought to think that a TTTG greater than 20 equates to a TTO. That is just not the fact. We can over-treat a lot of patients, and we must first obviously do no harm. I'm typically using TTOs for instability for combined reasons and for other reasons, like to unload cartilage defects, I will add enterization, or to combine with distalization for severe patella alta, as we touched on yesterday as well. And in fact, when we look at consensus statement written by Bill Post and Don Fithian, they say similar things, that there's really not good evidence to indicate just the medialization. So just based on one metric alone, and each of these metrics are not indications. They must be taken in gestalt and with a grain of salt. But they do concede that the AMZ does have a role in instability, particularly in cases of lateral overload, lateral arthrosis or chondrosis, and we'll go through that in detail in a few minutes. So then, when do I consider medialization TTO? I'd say at the very least, you need metrics that are positive. So you can see those threshold values that we measure, they need to be abnormal. But that's not enough. We need patient factors, such as these young patients, bilateral instability, low energy dislocators, so ones that really have aberrant anatomy driving the bus. And then one thing that I'm not sure we touched on as much are these subcritical values. So these patients may have dysplasia in their trochlea, but we're not exactly in the most severe types that we're going to treat. They may have subcritical values of patella alta and combinations of these. And a lot of patients have failed prior soft tissue surgery. So one for me, a 15-year-old female, non-contact recurrent dislocations in both knees, starting at age 12. She had the J sign. You can see her values here. So a high TTDG, and then borderline levels of catondesion, trochlear dysplasia, and failed approximal realignment. I would submit that for me, this would be a good patient for combined medialization and soft tissue stabilization. And in fact, that's what we did. And you can see a nicely balanced patella on her merchant view at a year post-op. And you can also see that she has an unbalanced patella on the opposite knee. She had symptoms of refractory instability and went on to require bony and soft tissue stabilization on the left knee. I think what's interesting and we can discuss in cases of dysplasia, is it worthwhile to move that tubercle medially to get to the center of the trochlea? Or when we have this medial hypoplasia and convexity proximally in the entrance, should we be moving that center of the groove laterally? And I think this is food for thought as we get more comfortable with these procedures and learn more about it. Maybe we'll be changing our ways. We touched on distalization and when to add it in patella instability. And this also remains a point of contention. If you're looking purely at biomechanics, the isometry of an MPFL, you might suggest that we should do this with values of Catan to Champ as low as 1.2. Because MPFL mechanics do not behave appropriately if you have higher values of patella alta. However, if you look clinically, this paper basically that just came out of France shows that if you do a well-done MPFL, the patella is now nicely centered in the groove. And actually, your measurements of patella height decrease after soft tissue stabilization. And so they concluded that in that 1.2 to 1.4 range, that distalization or the tool patella tendon shortening is not necessary. And other clinical papers looking at this look that it really doesn't affect subjective and objective outcomes until our CD ratio gets higher than 1.4. And so for me, I think my threshold for doing this is going up and up and up. And like David Dedook said, I'm in that 1.4 range at this point, but certainly a moving target. I would say for cases like this, 17-year-old, bilateral patella instability, severe patella alta, I don't have a way in my arsenal without including tibial tubercle osteotomy distalization amongst other procedures to get the job done. And you can see for this kid, this was staged procedures over several years, but getting him nice, balanced patellas and a very successful outcome. We looked at and presented at AOSSM last year about 100 of our cases using the indications that I outlined here. So unloading cartilage defects, rare cases of medialization and distalization, and pitting those up against the cases that frankly didn't need osteotomy and that we just did MPFLs. So you can see the cohorts essentially were the same to begin with. We can see that their subjective outcomes uniformly improved across the board in both of the groups. We can see importantly that the complication rates were not significantly different between those groups, which was good to see. And not surprisingly, at short or medium-term follow-up, the MARC scores, particularly cutting and pivoting or activities, were lower for the TTO group. I think that will and has corrected over time, but it can take, you know, up to extra six months or even a year more than other soft tissue procedures to get back with the combined bony and soft tissue procedures. So the rest of our time, I'm going to pivot towards including patellofemoral chondrosis and when to use tibial tubercle osteotomy. John Fulkerson's taught us about the strong correlation between the location of the cartilage defect and patient outcome. Here is his classic paper with Padoriano. And what we can see and what we know is that the isolated AMZ unloads distal and lateral cartilage lesions and has poor results for those ones that you see where there's medial defects or pan-patellar lesions. So in pain patients with chondrosis, good to excellent on the left and poor on the right. And so this allows us to really understand when we strongly consider combined cartilage restoration and osteotomy. And so we strongly consider adding cartilage restoration for those challenging cases where osteotomy alone is not sufficient. And so those include patients who have medial-based disease, pan-patellar disease, or patients with bipolar lesions. And in fact, when we look at our best data, TTO does improve the outcomes of cartilage repair. This is especially true for patella lesions and especially true for autologous chondrocyte implantation. As you see here, up to 80% good or excellent results treating the joint as an organ, alignment and cartilage versus just treating cartilage alone. Here's a paper that we recently submitted. Our fellows, Jay Calce, Kyle Soschacke, who better be on this conference call, looked at over 1,000 patients, matched cohort analysis, cartilage restoration plus minus osteotomy, and found that the combined group reduced the risk of operations with similar complications and interestingly similar overall costs. And so I would encourage you, if you're even thinking about cartilage restoration and osteotomy crosses your mind, that you should strongly consider doing it. A lot of this comes down to cartilage mapping. We see for those distal lateral defects that an isolated AMZ shifts the load and that without adding cartilage, we can get 87% good to excellent results. As a cartilage surgeon, I'm always trying not to treat the cartilage surgically. So I'm trying to get people better nonoperatively. And if I can't, I'm trying to offload the joint first and then decide if we need to proceed with cartilage restoration. In these types of cases, we definitely do not. So 25-year-old distal lateral chondrosis, 45-year-old lateral based arthritis, failed conservative treatment, isolated AMZ is an excellent treatment option. This is a rare one, but I include it because it happened to me and I've done this probably only a handful of times. An 18-year-old patella alta, distal chondrosis, subchondral edema, failed extensive conservative treatment like years, may have had a prior arthroscopy. I don't remember exactly, but not by me. And so basically fixed her alignment with an enterization and distalization and she wound up having profound pain relief over time, essentially distributing those loads and solving her biomechanical problem. Here's the case of the medial central and pan patella defects. And those are cases where we have to combine alignment with cartilage restoration to get those results upwards of that 75%. Here's a case of a 16-year-old, recurrent patella dislocations, painful effusions between episodes, which can sometimes clue us in to not just instability, but also to this combined cartilage abnormality. And what we can see is that there's a large focal defect of the medial patella, but this lateralized force vector with a TTTG of 22. You may worry that if you correct the alignment that you may shift those forces and load or overload medial, but I would submit that we need to treat not only with alignment, but also adding cartilage restoration, soft tissue stabilization, not over-correcting on your osteotomy, and this will get the job done treating that joint as an organ. When we're talking about technical tips for patella instability, we know we cannot use the MPFL to pull the patella. We need to complete the TTO first and then add soft tissue as a check brain to lateral translation. This is different than TTO with cartilage restoration, where we want to harness the fact that we can unhinge that osteotomy and leave it unhinged until after we access the joint. It's way easier to access, as you see here. This was a video that I did in fellowship with Brian Cole. It's on OKO, and you can access it, but you can see the easy access, and then we fix the osteotomy afterwards. So very different treatment strategy. When we're looking at our surgical incisions, here's my typical incision just off the lateral crest that we use for tibial tubercle osteotomy. As you get more facile, you can make this smaller. You can do a windowed technique, and so there are definitely ways to do this less invasive, but a lot of the things we're doing comprehensive, treating cartilage, alignment, stability, unfortunately are larger extensile approaches. If we need to add an MPFL, this is typically my incisions. So I do these three separate incisions, as you see here. If we're doing a TTO, adding a lateral lengthening or that cartilage restoration, this is that one slightly lateral-based extensile incision, as you see here. And then if we need to add MPFL, I can access the medial border of the patella through my larger incision, and then just do my smaller stab incision near the adductor tubercle to fix the femoral side of the medial patellofemoral ligament. When we're talking about adding distalization to AMZ, especially if this is a relatively small distalization, then we can use that feathering technique that David Dedook alluded to yesterday, basically keeping your distal hinge until near the end, and then completing that distal hinge with an osteotome, as you see schematically here. We want to normalize that Katanda-Chomp ratio, but we do not want to overcorrect. You can see this catastrophic effect of patella baja and arthritis that we want to avoid. And so I like the math here because it's very straightforward. If we have a CD of 1.4, we can calculate how much bone we want to remove here, 9 millimeters, to get to a CD of 1.1. I hate, hate, hate overcorrection. I think it can lead to pain, it can lead to chondrosis, so I'd much rather get it into that low normal range, that 1.2 or below, than to get 1 to 0.9, I think that can be a disaster. And so basically we stabilize, we mark, and we resect that distal aspect of the pedicle. One thing that we need to recognize, AMZ, you have that intact periosteal sleeve and it's green stick, and that may contribute to the improved healing rates and the periosteal blood supply. So when I do the distalization, I actually peel up that periosteum and preserve it, and then repair it after to the distal periosteal sleeve, as you can see here. There's different techniques for isolated distalization. These are some references that you can look at. This is one where you can do a freehand technique, and I'll show you that in a moment. So here you can see kind of the markings of that freehand technique. Essentially we'll start with that longitudinal cut, and you want to use copious irrigation. I like using the saw, and this is parallel to the ground, as you can see in this demonstration. The proximal cut is similar to any other proximal TTO cut. I love using the Army-Navy, pulling up at a 90 degree angle, so you really have protection of that patella tendon, and you can go straight across from lateral to medial with your osteotome. Then I like to leave the osteotome proximal and the osteotome lateral, and basically just crack that cortex that we see on the far side. And lastly, we'll turn our attention to the distal cut. We do our periosteal peel. There are different ways to do this cut. I've kind of gone more to a feathered technique, and I'll actually show you a whole different system later that I've moved to over the last year to do my distalizations. But I think key points, if you make this pedicle shorter, you're less in the diaphysis and may have less problems with nonunion, so it's something to think about. But basically, we can see here, completing with the osteotome, popping the top. We can manually rasp after we remove the distal bone. So we can take that bone, as David Dedeck showed us. We can put that bone proximally as a proximal buttress. I find that putting the knee in full terminal extension aids in this reduction. I think that you can use two 4.5 screws, or you can use three 3.5 screws. You can use them in or out of plane, as he talked about, to confer additional stability. You can see the bone placed proximally. You can see the sutured periosteum distally. If you want to add an unloading effect, we can put bone graft underneath, and we can fix with a K-wire provisionally, and then fix with our screws. So this is quite a versatile technique for distalization for instability, or for combined anterization-distalization with chondrosis. For the proximal buttress, there's not perfect evidence for this. Using that autograft bone seems absolutely acceptable if you have enough of it. You can clearly use allograft bone. You can use bone graft substitutes as well. There's been talk about doing a patella tendon tenodesis, where you basically put the distal aspect of the patella tendon into that site for the osteotomy, as you see on that bottom drawing. But what was shown in finite element analysis is that this actually increases the cartilage stress. And so for me, this is not recommended. Just to go through a couple of other indications. So salvage indications. Here's a 35-year-old. She had retractory patellofemoral pain, iatrogenic patella baja. You can see that her Katanda chomp is way less than one. She was absolutely miserable with this. And so for her, the solution was basically getting our tibial tubercle pedicle. We can flip it upside down, as you see here, and actually peel off that distal aspect of the patella tendon for about eight to 10 millimeters. And we can lop off that bone pedicle at the top of it. And then basically what that does, that effectively lengthens your patella tendon. And then when you put the bone back in its bone bed, you actually haven't changed the joint line at all. So it's quite a nice trick and tip to both lengthen the tendon and to restore patella height with the tibial tubercle osteotomy. You can see the kind of result that we can expect on that x-ray to the right, where we've really normalized the patella height without changing the joint height. So while this is fairly rare, I am winding up having to do a couple of these a year, and that's a fairly straightforward variation of a TTO. Here's a less straightforward one. This was a patient I had in Missouri, 45-year-old, low demand. Very bilateral symptoms from a prior Hauser procedure, basically where they took that tubercle and went posterior and medial, an absolute disaster. She presented on the right with severe chondrosis and on the left with moderate chondrosis, but pain from her malalignment. She wound up undergoing staged bilateral interventions. On the right, we had to actually do not only an anterolateralization and proximalization. You can see how far they moved the tubercle and how far we had to move it to actually get it back to an anatomic position. But because of her bipolar disease, we did patellofemoral arthroplasty concomitantly. Again, a rare bird, but something I think that we need to have in our arsenal as we get to this mid-age group. Then on the left side, we only had to do the salvage osteotomy, did not have to resurface her cartilage to get her a good outcome. She is well over five years now. She brought me deer jerky every year in the clinic. I don't think my patients in California will be bringing deer jerky, maybe some fine Napa wines, but I'm happy with this result. She was desperate and miserable, and I think that these are rare and certainly not things we do every day. As far as complications, we already alluded to these, but delayed union way more frequent when we unhinged the osteotomy. Also, 3.5 screws were less painful and less likely to be removed than 4.5 millimeter screws, so something to think about and something to consider. I've seen these complications. I've learned from them. This was unfortunately one of mine. This also is interesting for big distalizations. I've had some late basically non-unions of that proximal piece, which likely is a stress river above that proximal screw, and so I've just excised that fragment if and when it was symptomatic, removed the hardware, but haven't had to change the osteotomy, but it's something that I've seen, and so it may see some of you. I presented this data at Anna, I believe, a year or two ago. What we can see is that in the group where we don't unhinge, I had essentially no issues with fixation or with healing, and in the distalization group, we did have that small handful requiring that revision. I thought I'd spend a couple of minutes just introducing to you, if you haven't seen, a relatively novel set. This is the brainchild of Al Merchant, who lives in the Bay Area. You know him likely from the Merchant view. I've been so fortunate through the Patel Femoral Study Group and also through my time at Stanford to really get to know Al. That's him on the upper left. He's a real wonderful guy and one of the most forward thinkers I have ever known for the PF joint, and so this osteotomy was his design. It's a very different design than some of the sets that we'll see that are out there commercially now, certainly different than some of the freehand techniques that we might employ. What you can see from the schematic is that we actually cut the bone inside of both the medial and lateral cortex, and so there's no cortical breach with this type of osteotomy. You can see that there's that primary wedge, which is the larger wedge. I can point to it here, and then if you're doing any form of medial transfers, there's this smaller secondary wedge, and what you can see on the bottom saw bone is essentially we cut both those wedges, two exact specifications, and then just switch sides so that we can bring the primary wedge medially, bring the secondary wedge laterally, and all of that work is inside of the cortices, so it's quite a stable osteotomy. What I like it most for, and what I've used it for in the example I'm going to show you, is basically I can use this for combined realignments, so when I'm doing different degrees of anterization, medialization, and distalization, I can really dial those in with exacting specifications, which I personally found very hard to do with other freehand techniques. So this is from the AOS meeting that didn't happen, but it's on the Orthopedic Educator site. So this is the case. What we can see there, as Latul described, was that lateral vernacular lengthening, and we can use that kind of approach to come down to the lateral aspect of the tibial tubercle. With Al's osteotomy set, we really don't need a huge dissection into the anterior compartment. We put it on this guide basically right at the level of the tibial tubercle with unicortical screws, and then the first cut will be on the lateral side, and it's not through the cortex. We're maintaining actually that lateral cortex, so we have a nice safety margin from that anterior compartment. Once we've done that initial lateral cut, then the next cut is just to the medial aspect of the patella tendon. This is a fully guided system, as you see here, and so that first cut is basically just to the medial side of the patella tendon, and then, as you'll see in a moment, we put on an outrigger, and we know exactly how far over we want to go for our medial transfer, creating our secondary wedge. And so after we do those parts, similar to what I showed before, we get under the patella tendon, doing our proximal cut, and now we're just very carefully with the osteotome working to unhinge this osteotomy. So here you see that osteotomy bed. In this case, we're not only medializing, but we're also going to anteriorize and distalize, and interestingly, we really don't have to take off that much of the bone. We can actually widen the kerf of the recipient bed to help with our distalization, so I really only took off about two or three millimeters of the distal aspect of that osteotomy, and then I'm able to actually get up to even a five to a centimeter of distalization, which you'll see here in a minute. So here now, we have placed our pedicle back in the bed, and I was able to precisely measure the amount of distalization with a ruler, the amount of medialization, and I can also measure the amount of anteriorization. We can provisionally fix with K-wires. We can use, for me, with this osteotomy, I've actually gone to using headless screws to try to reduce that reoperation rate, so these are 5.0 headless screws that you're seeing here. This does require bone grafting in most cases, not in pure medialization, but in combined deformities, but that is quick-setting bone graft, and it's drillable. One thing that you saw in that range of motion video is that I'm assessing range of motion so that I can really normalize what Liza Oren likes to call the tibial tubercle, the sulcus angle. We really want that angle to be zero, and what that means in layman's terms is that we just want basically the patella tendon to be nice and straight through the range of motion arc. So for me, it may be a little less important. I know going in what my metrics are for medialization, distalization, but I'm going off of my clinical picture to make sure that I've done the job. I certainly don't want to overcorrect, but I don't want to leave the patient undercorrected either, so I think that's a very easy way to do that. So looks like we got through in good time, which will leave a nice amount of time for questions, answers, discussion, and debate, which is always the most fun. I hope I've shown you that TTO can be a powerful tool to correct malalignment in the setting of instability and or chondrosis. These indications and techniques are evolving. I'm not doing the same number of osteotomies as I was five years ago, and for some patients it's gone up, and for others it's actually gone down. And I think, as always, patient selection, meticulous execution, and appropriate rehab will give us the opportunity for an optimal outcome. And so I have these supplemental readings. We did a AJSM article on this a couple of years ago. I told you about the OKO article, and then a few other series and videos out there that can help you. But I think getting in the lab, getting to fellows courses or to some of those learning center courses, and getting with the PF faculty that's always so eager to teach and learn, I think are the best ways forward. Certainly if any of you have interest in Patel Femoral Study Group, I enlisted help of mentors to get involved, and I encourage you to reach out and do the same. And I thank you all very much for your attention. We can certainly chat now. And then if we do, I think, have time, I actually wanted to stir up the pot a little bit in the trochleoplasty world and show a little different type of trochleoplasty that some of us in the cartilage realm have been utilizing in rare circumstances. So we can get to that also. Thank you very much. When you want to do that, just let me know, and I'll mute Dave Dedeck. Yeah, exactly. And I need Adam Yanke, and maybe if Jack Farr is on, I need some backup before I make Dave have a heart attack. Awesome, Seth. That was great. I noticed on the x-rays where you had the broken screws, that looked like a pretty small diameter screw. What are you using to fix your osteotomies, and was that a smaller diameter screw than what you normally use? No, those weren't. Those are 4.5. Oh, really? Yeah, they were. So that one, I think that kid reported some traumatic incident also, but to me, that's a failure of fixation. The forces on distalization, and particularly large distalization, are enormous. So I think really maybe putting more screws or putting one out of plane, preparing that periosteal hinge so you don't get any risk of non-unions, all the tips and tricks we talked about. You have to go full cord press. And going slower with the rehab, I treat those differently than the AMZs with a intact hinge. So I go a bit slower on my rehab as far as keeping a brace, and discontinuing the brace until I am more along in healing. Or maybe a third screw, a la Dr. Dedeck there. Yeah, and some have even talked about small, low-profile plating. So I think one of the reasons that I was interested in Al Merchant said, particularly for distalization, is because you really have a much more stable construct. And I love the fact that you have that bone graft substitute proximally. And so I worry a lot less than I did when I was making those distal step cuts than when I'm doing these procedures with that particular system. But it is a learning curve also, and we need to report on our longer-term results with it before routinely advocating a switch, and such a drastic type of philosophical switch for everybody. Seth, great talk. This was phenomenal. And like you, I think I've morphed a little bit in terms of my usage of TTO and my patients. I think I'm doing more now than I did eight, 10 years ago. Your rehabilitation process for your patients, range of motion, weight bearing, brace, lock, and extension, for how long, and how are you bringing those patients along? Yeah. So if I have a standard medialization or AMZ, so an intact hinge, so I'm very comfortable with the healing and with the fixation, then that will allow me to go faster with the rehab. And I think I continue to evolve and go faster. So for me, that's a patient who has a hinged brace, locked, and extension initially until the wound is healed. That's toe touch or foot flat weight bearing. So for at least two weeks. If you have any concerns or you're just still conservative, I think doing that up to six weeks is not unreasonable, or at least up to four weeks. I've been shaving that down from six to four, and now, frankly, starting to weight bear those that I trust with the brace, locked, and extension, even as early as two to three weeks. For me, range of motion is immediate. So TTOs do not block my range of motion. I've proven in the OR that I can range them. If you have issues that would prevent you from ranging, with your TTO, you fix them at surgery. Things that will prevent me from ranging will typically be the cartilage restoration procedures. And frankly, even those, I'm fairly aggressive with range of motion. So very few limitations with range. So for me, that's early on either CPM or gravity-assisted range of motion. And then once I've documented healing at, let's say, four to six weeks, then when they have good quad control, so I really have not allowed them early on to do anything more than isometric, I will start introducing short arc quadriceps somewhere in that mid two to six week range. And then once they can lock it out, I can unlock the brace and discontinue. And that's variable, somewhere between six weeks. Some get it right away and can discontinue to a sleeve. Others, I need to really watch them and baby it between six and 12 weeks. What do you think? Yeah. Yeah. And I follow a similar approach. For my cartilage patients in the patella-femoral joint, for my TTOs, I let people wait there, as you said. So usually the first week, they're just touched down until they've gotten in to see the physical therapist. And then the physical therapist can treat them appropriately. I have patients wait there as tolerated with the brace lock and extension. If they can be trusted, I think there's no forces actually going across the extensor mechanism if they're in full extension. So I'm okay with that. I read in the Riot Act about not unlocking their brace. I think most of my patients are trustworthy, because it's hard. I realize that some of the patients who are obese are very big that we do these cases in. If you tell them to not wait there or be touched down, they're not touched down. They're going to bear full weight anyway. So I give us some guidelines. It makes their life a little bit easier. I actually think it helps the quad come back, too. So I get these people going right away. I get an x-ray at four weeks. I don't get another one at six weeks. So I see people at four weeks. I'll see them again at two months. But basically at six weeks, my physical therapist knows that they can unlock the brace and let them bear weight. I've been lucky or good so far, no issues with that. And I agree with Dave Deduck. I've transitioned now towards outpatient or sometimes 23-hour for the more involved cases. But using those nerve catheters, I think, has been helpful. That's in the anterior aspect. I haven't used posterior for theoretic concerns of compartments. Blood flow restrictions have been something we've used as an adjunct. TENS and STEM can also be very helpful and very effective. Obviously getting good pain control in some of these young females so we can get early range of motion and prevent stiffness, particularly when doing TTO plus and intra-articular procedure. Those are some of my stiffest patients that I worry about. So all hands on deck with the rehab modalities and try to reduce that risk. So there's a question from Jai Wu. Dr. Sherman, given the high success rate of TTOs for lateral chondrosis, what are your indications for combining it with an ACI? Yeah, so I think that the key point that I have is that one that Dave mentioned the other day, in most of these instability patients without pain between episodes, regardless of severity of chondrosis, stabilize them and then see how they do and don't over-treat cartilage. All MRIs that show cartilage treatments don't need a cartilage restoration. So that's like kind of, you know, point in fact, you know, number one and two. Then I turn to can I get away with just unloading the joint and shifting from areas of bad cartilage and malalignment to areas of better cartilage with normalized alignment? And so the perfect example is distal lateral chondrosis with malalignment doing an intermedialization, shifting to good medial and proximal cartilage and not doing an ACI at all. That doesn't mean that you don't take an ACE in the hole and maybe take a biopsy and save it for a rainy day at the time of osteotomy. And it doesn't mean you don't educate and counsel your patient that if they have persistent pain and swelling after they've rehabilitated, that they might need that. But it just means that I'm trying to simplify. It reduces morbidity, stiffness, cost, all the above. And most of the time that's effective. Now, that's not necessarily effective with panpatella or medial or bipolar problems. And so in that type of scenario, that's where I might do a staging scope first. I can get a lay of the land. I can again take a biopsy. And then I come back for the comprehensive bigger surgery with the osteotomy plus the cartilage plus soft tissue balancing in that order. Here's Nicholas Reyes asks, does a, I'm assuming you said a large ossicle from Osgood's slaughter change your management in the patient with instability and a need for a tibial tubercle osteotomy? No, I think a lot of those are incidental. You know, I think it's changed my management for maybe doing a patella tendon autograph for an ACL and maybe I'll do a quad, but not really for a TTO. I think I haven't been faced with that, but I would be fine with plucking it out of the tendon and then going about my osteotomy business as usual. Okay, here's one from TLC. Do you have any tips on wound closure to minimize complications of the wound? Yeah, I think, you know, I'm super concerned about this area and wound breakdown. I think, you know, I know I've had wounds that have had either superficial infection that need tending to or deep infection and one that, you know, needed actually soft tissue coverage. So this is critically important. I do not use a tourniquet. I rarely use a bovie on many of the layers. So I think meticulous handling of the soft tissue envelope, I typically am not using, you know, Vicryl, I use, you know, Monocryl, even on some of those deeper layers. And I'm looking to some of the more novel wound closure devices on the superficial surfaces. I haven't been fully pleased with any of them to date. Maybe the other panelists can comment on any tips and pearls to prevent wound breakdown. I mean, right now, I'm doing actually more robust nylon sutures on the skin over the tubercle, just to be safe. I think it's your incision placement, I think, helps you a lot, right? I think by not putting the, you know, by being a little bit more lateral and then you're intermedializing, I think that helps. If you put your more of a midline incision, I think you're more at risk, personally. But let me ask, so, you know, Latul and you were talking about the early weight bearing. And I'm curious of Dave's approach as well. I mean, you know, when I was a fellow, and I was, you know, there were a couple of cases that were reported of people that did fracture their tibia after a TTO, a Fulkerson osteotomy. And so, and I had let people weight bear full extension, like most of my patellar procedures. And after that, I went back to, you know, touchdown weight bearing until the thing was more healed. And so, I'm just curious, is that still, am I just being very old school and you guys are letting them weight bear earlier? And the other is, do you guys use drains to reduce the risk of, you know, compartment syndrome? For me, you know, when I, if I'm going to keep them overnight for a 23-hour stay so they can get pain medication if necessary, then I'll put the drain in. You know, it might as well since they're there and give them some antibiotics and then pull the drain in the morning before they go. But are you guys draining your TTOs as well? So, with the classic AMZ technique, where I go, you know, and peel the anterior compartment, I was using a drain, and if they're staying overnight, I would use it. With the Almergens system, we're really just exposing that anterior most aspect of the, you know, periosteum over the anterior compartment, so we're not even going into it. So, I haven't used the drain with those. Maybe David, do you want to chime in on the weight-bearing aspect? Sure. Sure. My approach has been to go 50% weight-bearing, two crutches for six weeks, and let them range. So, I don't force them to do ambulation with the brace locked in extension and let the brace be unlocked. I go zero to 70 for two weeks, then zero to 90 to week four, and then full range after week four, get an x-ray at six weeks, confirm healing, and get them out of the brace and crutches. Then, if they're slow to heal, I'll go an extra week or two on the crutches, but 50%. And knock on wood, I've not had trouble with hardware failure or fixation failure or wound issues, actually. There's a couple of other things I would just offer. It's interesting to compare techniques. After an AMZ, the cavity that's left on the lateral side, I will pack with allograft chips, and that seems to tampon out the bleeding that would come from there very effectively. The other thing is you don't have to take the anterior compartment muscles down. So, that, I think, is a big help and helps with the pain. I don't need to drain, never used to drain for these, and that hasn't been a problem either. But as you make your medial cut, I go just through the medial cortex until I get to the level of the distal screw, and there I go bicortical across and feather it out distally. And then, as you showed with your osteotome coming approximately, make that cut behind the patella tendon, and then intersect that coming from the lateral side distally. You make just a small window in the anterior compartment fascia so your osteotome can slip under the muscle. And as you take the osteotome down tap by tap, it just splits like a block of wood. It intersects your other cut down at the bottom. Your entire anterior compartment muscle is undisturbed, not lifted up at all, and then you can take a towel clip and manipulate your shingle to the desired location and then fix it with the screws. I put the drill bits in to hold it. I've pre-drilled by near holes for these, put the drill bit into the far side to hold it, and then complete those. And I don't take down the anterior compartment on any case, even a distalization. I think with my 10 or 12 or so that I've done with the new system, so not taking down anterior compartment, the pain relief, you know, has been quite different early on. So maybe from some of the teachings that I've had, and taking it down and using a big neurovascular retractor, you know, is unnecessary. That adds a lot to it. Yeah. And the other thing I'm able to do is go with an anterior medial incision, thinking about whatever's down the road for that knee, and that's kind of the workhorse exposure. That was a fantastic talk, Seth. Just really, really well done. I want to make you throw up now. Can I do that for two minutes? I'm getting your thoughts. It was fantastic. I was waiting for the compliment, and now... Absolutely, it was a fantastic talk. We still have over 100 people, so we have some controversy going. There's still, Seth, before you go down that, there's still a couple of questions, if you don't mind. Okay, fine. Save me a few minutes, though. I'll save you a few minutes. So, first of all, so we'll try to make these quick responses. So, Alexander Brown asks, how are you determining the distance you medialize your TTOs? Yeah, so, you know, from my presurgical planning, I'm measuring, you know, my TTTGs and my TTPCLs. I know what my target metrics, you know, will be, so we want to get into that normal range. So, that's kind of that 10 to 12 range, and usually bring it over, you know, 8 to 10, but it can vary. But I think more importantly, I'm looking at that clinically and looking at that clinical tibial-tubal-to-sulcus angle. So, really just want everything lining up down the middle, and that helps me for the medialization. For distalization, I showed you kind of the orthopedic math, so that one's straightforward, just don't overcorrect. And for anteriorization, we don't have perfect metrics for what's abnormal and how much we want to correct it. So, if I'm offloading, you know, I think the things we worry about are too much anteriorization and the McKay effect and soft tissue breakdown. So, you know, I think you're going in that 5 millimeter, 8 millimeter, something like that, seems to be a safe and comfortable range. Okay. Jeff Guy, you got, you had a, from South Carolina, you had a question for us. Hey, guys, how are you? Yeah. Yeah. Welcome. It's nighttime here. I was, you know, one of the things for me, and Seth, you and I have had this conversation, you know, I just want to toss it out there for everybody else. You know, I'm pretty critical at this point in time. I won't even operate on anybody unless they have their vitamin D within a, well within a normal range. And just anecdotally, I really think it's helped a lot because it's amazing the vitamin D levels for some of these kids that come in that have a vitamin D of 5, 10. You know, that's almost, it's almost gone. And I really think it's critical to helping these osteotomies heal because I've had the same problems as you have. And getting these to heal, I think anything you can do, soft tissue, I use drains, but anything you can do to get them to heal and maximize, it's pretty low-hanging fruit to get a vitamin D level. That's a great point, Jeff. And hopefully it goes without saying, but, you know, at least in America, I think none of us are operating on smokers. So if people were smokers, you know, or nicotine, they quit their blood, their lab tests, we can send off now to prove it. And it's part of the engagement process for these, you know, larger surgeries. So, you know, I think anything to optimize and reduce the risk of complications. I'm with you, Jeff, on the vitamin D. I think that's huge. Yeah, yeah. Well, you know, you guys live in sunny places. In Ohio, you know, it's not like sun, so everybody's low. Our things are a little bit more hardy here. Maybe I need to look into that a little bit. I don't know. I put all our basketball players on it prophylactically to help reduce stress fractures. I think a lot of athletes that are, you know, indoors or not much sun, you gotta be cognizant of it. So here's an interesting one from Nicholas Reyes. Do you have any experience with proximal tibial derotation osteotomy? And what's the limit, what are your consideration of the limits between a TTO and a derotational osteotomy? Yeah, I think that's a great point. You know, I think that while we're always looking for the rarer birds and always quantifying these different deformities, we're not often acting on them. When I was at Mizzou, I had a protocol. So not only my clinical exam looking at torsion version, but also a protocol as part of my MRI. I can get spot imaging of the hip and the ankle and then at least know what those values are and if they're extreme outliers, you know, you can maybe go that route. I have no experience with it. Others like Bob Taiji have tremendous experience with rotational osteotomies. You know, but, you know, I think if there are multiple deformities and I'm thinking about doing an osteotomy, I tend to choose the one that's closest to the actual pathology, which is the TTO. So when I'm faced with, you know, should I do rotation or TTO for complex malalignments, I'm usually going to the knee first for better or worse. Okay. Santiago Pache, I hope I pronounced that right. If not, I apologize. What do you think of the biomechanical consequences on the patellofemoral increased contact pressure after isolated TTO distalization and have you had patellar contour complications in those cases? Yeah, so I think that's kind of somewhat of a misinterpretation in my opinion. If we are distalizing for ALTA, which is overloading the distal aspect of the patella, then by normalizing and not over distalizing, we actually increase the contact areas and reduce contact pressures. And so I think you actually are making it better and not worse. If you bring it down too far, then clearly you're making it worse and not better and you're causing, you know, overload and destructive chondrosis. So I think that one of the papers out there, you know, kind of took normal, made it abnormal. I think that was unfair. I think you have to take abnormal and make it normal. Okay, last two questions before you go on your trochlearplasty tirade. Might have to do overtime. So when you enterize, this is from Federico Gili. When you enterize the tibial tubercle, where do you get the grafts if you use an autograft? So typically if I'm using bone graft underneath an enterization, without distalization, I'm gonna use an allograft. But I think you can, if you need autograft to pack in, I mean, you can take some from the proximal tibia or you can make windows elsewhere, distal femur, I would say. Okay, and then Peter DeLuca said that it's been reported that there's about a 4% incidence of DVT after TTO. Do you routinely use DVT prophylaxis? Yeah, I've gone back and forth with this, even as far as using Lovenox, excuse me, Xarelto for all these patients. That led to the other end of the spectrum was a couple of bleeding complications. And so for me now I'm using aspirin and multimodal in the OR aspirin and early range of motion. How about Dave Dedeck, Latul, Jeff, are you guys using your prophylaxis? Dave, you're on mute. Dave, you muted yourself. Same with that, I use aspirin. I worry about healing as well as bleeding complications. Got it, Jeff? Yeah, I use aspirin and I've had a couple of people get DVT. So we put them on two baby aspirin, usually for normal people for at least two to three weeks until they're up and moving. Cool, all right, Seth, prophylaxis rebuttal. I'm gonna make this super fast. Wait, wait, here, I gotta put Dr. Dedeck on mute so he can't unmute and go. I just wanna introduce to everybody a alternative that's basically a Lars Peterson grooveplasty or an entrance trochleoplasty. And the indications are clearly evolving and controversial, which is why this is bonus material and certainly up for study number one in debate. But here's when I use this at least is when you have that large central supratrochlear spur, you also have that jumping J sign, we have a well-contained patella or you've distalized to contain it. And then I think the key point is that you need a long trochlea. So to me, that means a high crossing sign and a crossing sign that's not too anterior in reference to that anterior femur. So if I have one that Dave showed or a lot of them where the entire trochlea is elevated, then there's no way in the world that this is going to work. So there's clearly, in my opinion, a large role as Dave showed for deepening, but maybe a minor role for entrance trochleoplasty. Why this is important to me is because it's easy to do. I mean, you just saw it, I basically lap off the spur like you see in that picture. And so what this looks like clinically is kind of taking off the ski mogul. And so you flatten out the entrance so that the patella doesn't jut off to the lateral side, you can reduce the J sign. And typically you're only taking five to eight millimeters of cartilage. Most of that deformity is bony. There's a lot of unknowns. This should be studied. This should be in specialty centers only. We should debate this at Patella Femoral Study Group. And this may be something that we just don't, frankly, do over time, but I know that a lot of us are doing this and maybe the silent minority or majority in the cartilage group. And I just thought it was worth showing you. I mean, here's kind of intra-op. So you can see on the lateral, we know where the crossing sign is, which is where the bottom of that dotted point is, where the trochlea becomes flat. And then everything above it is that bump. And so basically similar to what Dave showed, you elevate that synovium, and then we're getting rid of cartilage over that bump. You can see a lot of bone boss underneath it, which is the deformity. That ring curette is small, remember. So it looks really big on this beautiful image, but it's not a big area. And then like a cam lesion of the hip that Mark knows well, you can really taper down to the anterior cortex and get it flush. And so that's what our laterals look like. You can see the crossing sign is kind of at the level of the anterior cortex and not way anterior to it. So I don't know whether this should have a role. I'm gonna, can you unmute Dave Dedook so he can have the final word on this? But I just thought that a little controversy is fun. And if he tells me to stop doing it, I'm gonna stop. Do you really want me to do that? You sure? Yeah, do it. All right, Dave, wait. I think I, no, can you unmute yourself? There you go. Yeah, Seth. There you go. Yeah, Seth, that's great. I mean, I'm always learning and this has been described and I just have a hard time wrapping my head around it because I can preserve all that cartilage and get the same effect and drop it down. But when I was describing the technique I do, the extent distally that I carry my cavity is where the anterior femoral cortex would intersect the cartilage as you come around that curve. And for you to get rid of that bump completely, you would have to go down to that level distally, which would really creep into the articular surface that matters. So that's the one concern I have. We're accomplishing the same goal. We're getting rid of that spur, but with the technique I'm talking about, we're preserving the cartilage. Yeah, I think with a shorter trochlea and whatever that may mean, and with deformity that goes more distal, or with the entire trochlea way elevated anteriorly, I think there's no way that you can do this. So, you know, I think we're studying our results. We're going to pull them and report on them. And I think technically, obviously, this is a lot easier to do, but we certainly don't, you know, I do not encourage anyone to make this mainstream in their practice. I mean, this is, you know, something that we should be discussing in, you know, those of us who do this all the time and who kind of do both deepenings or entrances. And I think if I had a patient, based on your indications for an entrance, or for a deepening, I'm going to do that. So it's not one or the other in any way, shape or form. Very good. Cool. Well, I think that's our time is up and we got through all the questions, Seth. Awesome job. I just want to know how you're able to get your trochlearplasty pictures into entertainment tonight. You know, you've got that ET there, you know, that you're getting, you're going live big time, Hollywood style. I just hope I don't get a call from ALS, but the meeting was canceled. Well, thanks everybody for participating. Appreciate it. Tomorrow, we have Brian Feeley from UCSF who's going to be talking about the role of muscle quality and rotator cuff repair. So thank you all very much and I appreciate this was a great patellofemoral session, guys. Seth, Latul, Dave, and everybody who's contributed. Much appreciated. I know the fellows appreciate it as well. So thanks everybody. Have a good evening. Take care and be safe. Thank you. Strong work. Thanks, guys. Take care.

tibial tubercle osteotomy

patellofemoral joint

instability

chondrosis

surgical technique

postoperative rehabilitation

malalignment

cartilage repair

patient selection

trochleoplasty