Chapters Transcript Video Professor Max Ettinger: Overcoming UKA Challenges with New Implant Design and Handheld Robotics Live surgery video that provides an overview of the surgical workflow for partial knee using JOURNEY II UK Knee System and the CORI Surgical System. Ladies and gentlemen at home. Thank you very much for attending our webinar today. As we heard, Unicompartmental Neoplastic is a challenging procedure. And I'm gonna continue showing you how robotic technology might help us becoming even more successful with this wonderful implant. In my opinion, a successful uni consists of three things. The first thing is we have to respect the patient's individual anatomy. The second thing is we have to fuse the bone anatomy and the patient's individual soft tissue balance. And then the third step, we need a super precise tool in order to conduct our plan. The good news is with robotic technology, we can combine anatomy, balance and precision in an individual anatomy and balance concept, what I call the robotic workflow using cori and this is how it works. So, in the beginning, we're gonna do a planning with the individual 3d morphology of the patient. In the second step, we're gonna capture the patient's individual soft tissue laxity. And in the third step, we're gonna execute our plan with the robotic handpiece quarry. And that's what I'm gonna talk about now. So why is alignment and balance um crucial and important in order to conduct a, uh conduct a successful uni it's because we have certain biomechanical boundaries we have to stay in with. This is a good example of a medial uni. As you see here, we have a medial osteoarthritis. And after the manual operation of this patient, this patient was overcorrected into about 3° of agus and that has a really big impact on the patient's balance. This study was conducted by Thomas Heiser a couple of years ago where he checked this effect over correcting a uni and as you can see here, this is zero and 90 and 100 degree a reflection and the MC L strain um at its baseline in the native knee. When we overcorrect the knee with the UK, we enhance the strain on the MC L very much in extension and even inflection. And those are the patients that suffer from severe and long lasting pain and they might be due to an early revision. Secondly, concerning alignment and balance, we know that we should never overcorrect into vigus because we will gain better results when we do what we call a minor virus under correction. So if we have a virus, osteoarthritis and put in a uni we should under correct the patient and virus. But the thing is that we never know manually how much virus we will actually leave in the patient. So it's very important to have a precise control about this. And then the third step, we have a so-called safe zone where our uni has to be placed in. So we should not distal the joint line by more than two millimeters. For example, we have to keep the physiological joint line height and obliquity, we should not go um below five degrees of slope or differ more than two degrees of physiological slope and so on and so on. And when we look into the literature, how good we are balancing and operating our uni into the so-called safe zone, it's only 10% of units that are placed ideal. So in the end, we need a precise tool in order to stay within our safe zone, I brought a case for you today. Um This is the classical not so easy uni why? Because we have a bone on bone situation immediately. So we have a correct indication. But if you look at the axis, this case is almost straight even though we have wear on the media side. So this is a case where you are easily um uh where you easily overcorrect the limp uh into a slight vagus um uh orientation when you don't use technical help. So bone to bone situation, 3.5 degrees of virus over limp alignment. And now I'm gonna take you through the case showing you a 12 minute video of how that works. So usually I do a media power pala approach as you see here uh that standard, then checking bone on bone on the media side, you don't have uh the, the, the, the noise now, but it's bone and bone here. Uh Of course, we have to take away um our osteophytes that uh will um uh alter the joint balance if we don't take them off. Uh As you see here, I checked the lateral compartment uh for osteo um uh changes pin placement very important in the uni case, I put the first pin right behind the trochlea. Of course, I don't want to harm the cartilage there. And then I place the second pin within the wound sometimes and sometimes I will just make a um stitch incision uh through the skin. In this case, for the video, I put it in the wound uh to have a better exposure. Um use some sort of need a bigger exposure in order to really evaluate the lateral compartment as well. And then the most important part, we have to collect the patient's individual soft tissue properties by putting um vital stress into the knee. So we want to open up the media compartment in order to um really get a feeling about the baseline. Um um the baseline, um ligamentous uh properties of the media compartment. In order to do so, we have uh different options to do that. Um For the uni I always use um what I call the Z retractor, you see it here in my hand. So you put the retractor in the knee and then open up the media gap with a con conti continuous force throughout the whole range of motion. This baseline curve is really important because if you don't get that curve correctly, you will deal with um the wrong soft tissue properties. Afterwards, then for the femur, we need to define certain landmarks, the knee center, for example, the most distant part of the con di and so on and so on. I'm doing that with the, the pointer that comes with the machine. Uh really important is that taking the anat to me and the anatomical landmarks is really something you have to take good care because if you get the anatomy wrong, you will work with the wrong information later on. And then I'm mapping the joint line surface here. Um That is really important to stay on the bone with the pointer because we want to align our prosthesis to the shape of the bone. Afterwards. When we are in the planning window, the computer is calculating alignment and size of the prosthesis by using this surface. Really important is and I'm switching around the view now is that you collect enough surface here posteriorly because we don't wanna lose posterior nila offset on the media side. So it's really important that we map the anatomy correctly when we are done with the femoral side. Um We go to the TB R. Um We have to map certain anatomical landmarks here as well. Knee center, low point of the TB A plateau. Very important for um correcting the or, or the correct height. Um Most media point, most interior point, the machine is using those points for calculating the correct size. And then of course, in the end, um we need to define the um intercondylar M and N ridge that is really important because the computer will align the TB A base plate um according to this line. And um I will just calculate or define this line a 90 degree reflection aligning the pointer um to the con dial in order to have a good matching between and tibia. Then of course, um as well as we did on the femoral side um mapping the tibial bone here. Um in this step of the surgery that is really important because once again, we are working with an imaged less system. So we have to feed the computer with the information um that we need for placing our implant, right? Um That is pretty easy. So, um all over mapping uh in the UK A takes about 15 seconds on the femur and not more than 25 seconds on the tibia. Sometimes it's a little bit hard to get right in the back. That's what you see here. So you have to put in a little bit force sometimes to get the pointer uh to the posterior part um of the TV R. But most of the times works um without any problems. Then after we are done with mapping the anatomy. We are going to the first planning window here. You have a good overview of how coy works. So I'm working with uh the screen you just saw in the video um all the time in the implant placement window, we now have the chance to check for our initial placement of the femoral component as well as the size I'm working um in the upper right hand corner at the moment, checking the size. What I always do is um I take the um trial implant that the computer suggested me uh and uh align it um here to the because I wanna check if the size is really um the correct one. And then I'm beginning with the initial placement of the prosthesis. So you see here, the very nice anatomical fit of the journey to UK and I basically align it to the anatomy of the femur that is really important. Um because in the end, we are still doing micro adjustments in the balancing window and that is something I will show you later. But what you can see here is you always have to make up your mind um if you had wear or nowhere. So in this case, I had nowhere posteriorly. So this is inta cartilage, it was a pure extension gap disease, um knee, but I had uh wear distally. So I have to think in my mind that later on, I will probably have to compensate for the wear distally. The second um implant placement window is uh on the tibia side. Um On the upper left hand corner, I have full control about my media lateral placement of the prosthesis. This is a little bit too far lateral. So I have to shift it a little bit immediately. Here. I'm checking for the slope. I just said in my initial uh slide that um five degree of slope or six degree of slope is my personal maximum. So what you can do is you can really check and align the prosthesis to the natural slope of the patient. Um And um you can uh correct the joint line of liquidity and the physiological MP T A a little bit as well. So I put two degrees of aros here uh into this tibia in order to mimic um the patient's natural MP A on the medial side. But once again, everything I'm just doing is just a matter of uh pres because the big thing and the magic happens in this window. So we have still the opportunity to change all degrees of freedom of the prostheses. But now under full control about concerning our balance and our access. So we see that this patient comes from two degrees of virus. And if I would plan the prosthesis like it's planned, now I would end up in three degrees of virus with about 3.5 millimeter um gap in extension. And a pretty tight flexion gap. So the beauty of the system is now that I can fuse and combine um the bone anatomy with the soft tissue balance. So, what I have to do here is I have to get tighter in extension and a little bit wider inflection. As I as I'm al already resecting five millimeter on the tibia, I have no option to compensate over the tibia. So I'm distal the femur a little bit. And what you can see here is that I'm just compensating for the way distantly, whereas I'm reconstructing the ephemeral anatomy posterially basically one on one. And that leads me to a perfect balance curve in the end because I want 1.5 to 2 mil in extension and uh about one mil inflection. So everything you're just seeing is playing around with the prosthesis, how it um basically influences balance and alignment. This is for me, a pretty much perfect balance curve. So I come from two degrees of virus and I will end up with zero degrees of thyro very important until this step. I didn't do any cuts. So I'm basically simulating the post operative situation um at this moment and I can be sure that I will uh don't that I don't end up in Vagos, for example, and that I have uh the perfect balance in the end, um very important and fairly new and that is something uh you will um experience when you start with robotic assisted surgery, we have more information than ever. So in this window, just before you start, the cutting, the computer is calculating the femoral tibial contact point posteriorly. So you see here that the prosthesis is well aligned femoral tibial in the end and that of course, will avoid edge loading. And you can be sure that you guarantee uh long li of your implant the conduction. Um So the execution of the plan is then done with the quarry robotic handpiece. Um And um we have different modes um of execution. I'm using the so-called exposure mode at the moment. So the burr is coming out of the tube um only when we are in the area where the bone has to be removed. So the purple is uh basically the bone bed where the implant has to go. So we are preparing the bone on the distal femur, as you can see here, it's a nice smooth area. Uh We have full control um within 0.5 millimeter of precision of what we are doing. So we are taking away the bone for the prosthesis. And um of course, we are burying the holes for the packs as well. That's pretty easy once you're used to doing this, um the femoral side in the uni will not uh take you longer than one minute. So it's very, very, very fast. Uh And then we switch to a different motors on the tibia side. So we are the tibia. Now, as you can see here. Uh And once again, the purple is the bone bed for the tibia uh base plate. And we are just buring away uh the bone. And um the robotic part of the procedure will then um help us to execute our plan by uh with a precision of 0.5 millimeters. This is almost the end of the procedure. Then we are checking um our result with tri loop plants. Um That's what you see here now. So putting in the onlay and then in the next window and we have full control um over our results. So we see that we ended up in um zero degree, one degree viru zero degree, basically exactly what we are, what we were planning. We have free range of motion until deflection. Uh We have full extension and that's very important um for the documentation as well. Even more important is the last window of the procedure uh by putting viral stress into the knee, um the computer will calculate us a real time curve. How big our gap actually is. And the dotted line here was the line we planned and the orange line here is what we got in the end. So you see that we executed the plan uh basically precisely by one millimeter, we are perfectly balanced um with a perfectly reconstructed physiological anatomy um of the station using the robot. So in the end, um we have a perfectly aligned uni within the concept of personal personalized alignment P A using robotic technology. So in the end, the conclusion is that the robot really gives you um the chance to um execute personal uh personalized aligned um philosophies by bringing anatomy and balance um uh into a perfect fusion and the quarry robotic handpiece um basically combines anatomy, soft tissue balance and precision. Thank you very much. Published April 5, 2023 Created by Related Presenters Professor Max Ettinger View full profile
