Dr. Savyasachi Thakkar discusses Kinematic Alignment vs Kinematic Implants
Good evening everyone, we welcome you all to our toe tv original webinar series. Uh Today we have with us uh dr service proxy tucker, he is uh based in uh us. He's attached to john Hopkins University and he's arthur plastic surgeon. He's going to talk on china. Matic alignment was his cinematic implants. And we also have our Panelist with us. Dr Garo Kennedy is assistant professor in diva party Hospital and Medical College in Nehru Navi Mumbai. So, over to dr sanderson attacker to start the presentation. Mhm. Thank you very much. Dr bijani for inviting me and dr dr Gaurav comedy for moderating this session. Uh Good morning to everyone in the United States and good evening to everyone in India, I hope that you all are safe. So today I'm going to be speaking about this concept in need replacement or knee ultra plastic called Kinnah Matic alignment. Which is a little bit different than the traditional insole and rana with mediated uh mechanical alignment. And I'm also going to compare it to the newer generation of implants that are called cinematic implants. To see which one is better and alignment, philosophy change or an implant change to restore an atomic function for total knee arthur plastic patients. My disclosures. So I am I work at the johns Hopkins Hospital in Baltimore. We have several different hospitals between Baltimore and Washington D. C. And I'm also a consultant designer for Earth a line which is a portable navigation system. So my objectives of this talk are number one to provide an overview of the various different alignment systems that we have available to us to align a total new art plastic prosthesis. Today. The traditional is the mechanical alignment or sometimes also the anatomical alignment. The newer techniques are things like adjusted mechanical Kinnah Matic and then restricting our indications for alignment along that there has been this uh this this invention of new implants or this introduction of new implants which are so called Kinnah Matic implants because they are designed to restore the native cinematics of a knee. So some examples that I will be discussing today are rotating platform designs, medial pivot designs and asymmetric design. And finally a design which retains both. The cruciate ligaments, the A. C. L. And the PCL. So it's a bike cruciate retaining design. Now, the idea of this talk is to compare alignment to compare implants and figure out what fits best for your practice in your hands. Because as a young arthur, a plastic surgeon, these debates and these challenges can be quite daunting to try and figure out the best possible path for patients. And the reason I bring this up because unlike a total hip replacement, A total knee replacement has an 85-91,90% chance of success and about a 10-15% chance of failure and patient dissatisfaction with their surgery. So this is the Holy Grail. We don't know why some of these patients are failing and maybe it's an alignment issue or an implant issue or both. So let's explore this with the current evidence. And this is my friend Charles revere, who's a french surgeon, a french trained surgeon who works now in London, United Kingdom. And he published this wonderful review on alignment options for Total me arthur plastic. And the reason we have to think about this is because there are some patients, especially a lot of patients in europe. Professor Bellman's johan Belmonts and Belgium came up with this concept of constitutional virus. So there are some patients, especially soccer players, athletes, runners who have this native virus deformity. Now, if you take that patient as shown here on the left and you make them into a neutral systematic alignment technique. As shown all the way here on the right of your screen, will that patient be happy or will they not be satisfied with their totally prosthesis? So, if you start with such a patient, you go all the way to the right. You see that there are two systematic alignment techniques that we have traditionally followed. The mechanical technique, which means that the implant, the axis of the implant is perpendicular to the mechanical axis, drawn from the center of the femoral head, all the way down to the center of the knee to the center of the ankle, or you could use an anatomically Alliant technique with some federal modification and put the joint client in a little bit of values. Then there are hybrid techniques in which you have restricted Kinnah Matic and adjusted mechanical by putting in some joint line of liquidity. And finally you have patients specific techniques. The most obvious patient specific technique is a unique unlearning arthur plastic because you're preserving your crucial ligaments and your collateral ligaments and are really not supposed to perform any releases to balance me. So you're putting in an implant and just resurfacing the knee or you extend that to a totally prosthesis. And that's known as a kid. A Matic aligned me with joint line of liquidy. So let's formalize these definitions. Mechanically aligned me as we discussed is perpendicular to the mechanical access. The an atomic aligned me has 2 to 3 degrees of joint line vargas built into it. In an adjusted mechanical model. You are under correcting that frontal plane or corona claim to within three degrees. And you're doing that predominantly by modifying the federal cuts in a kid thematically aligned me. It's a purely bony procedure without any soft tissue releases. And you're keeping the patient where they came in. So it's a very patient specific model. And finally, some of the early adopters of the Kinnah Matic lee and me also discussed this concept of restricted Kinnah Matic in which you're restricting your indications to perform a key thematically aligned me to within three degrees of deformity in the frontal and the central plains And within 5° of joint line of liquid ease. Anything beyond that. Most of us are then going to the mechanically alignment. Yeah we have a little bit of a. Yeah. So now let's let's compare the Kinnah Matic lee aligned technique to the mechanically aligned techniques. Okay, automatic alignment. Again as a patient specific approach. Mechanically alliance is a more systematic approach and I'm going to highlight some of the important differences when you're rotating the femur in your cross sectional plane and mechanically aligned me you're typically building in some external rotation compared to the posterior consular access about three degrees of external rotation. Sometimes you vary that 257 degrees if there's a hypoplastic lateral federal con dial to account for a valdas deformity in a cinematically aligned me you're keeping that neutral rotation. The rotation has kept neutral and its relative to the posterior cruciate ligament. So you're not building in any rotation secondly, in a federal component positioning and sizing between the anterior posterior dimensions. You are only using posterior referencing techniques because you're using those con dials to come up with the size. You're accounting for somewhere in those condoms but you're using them. Whereas in a mechanically aligned model you can either go by anterior referencing so the anterior temporal cortex or by the posterior con dials. And we may switch depending on how much posterior candler where there truly is. Then in terms of the tibial rotation and the tibial cut. So the frontal table cut. Normally we in a mechanically aligned me we want to make sure that the tibial joint line is parallel to the ankle joint line, assuming there is no deformity in the tibia and the tibial shaft. But in this case in the kingdom every case there is no attention paid to the ankle. Those are considered to be independent and it's considered to be a part of the constitutional alignment of the patient. What about tibial sagittal positioning in a kid a Matic airline me you're making sure that your vaginal access of the tibia is parallel to the medial tibial. Soon so there is more attention paid to the medial tibia with regards to the horizontal table positioning. You are more parallel to the lateral tibial plateau access. So now you're you're access switches in a cylindrical fashion from the medial side of the tibia to the lateral side of the tibia. With regards to Federal Table joint. In terms of soft tissue balancing mechanically aligned me as john and saul idealized that this is a soft tissue and a bogey procedures. So once you make your bony cuts, you're also performing soft tissue releases. But in Akina magically aligned me. You're not doing that. Your goal is to restore the constitutional knee alignment and thereby is to restore the constitutional knee laxity without affecting the ligaments. And finally there is also no soft tissue balancing when it comes to the extensive compartment in a cinematically aligned me? So those are the fundamental differences between K. And N. A. Techniques. Now, what about different implant options that are available to us today? So the first is a rotating platform. So I have an example of a fixed bearing trade in which what you would do is you would put this polyethylene into the trade and you would lock it in place. But a rotating platform allows certain rotation between the devil polyethylene and the underlying trade. The reason this came about almost 10 to 15 years ago was to uncouple the translational and rotational forces. And there are two ways you can do this. One is by having a central pivot. So again going back to my example, you can see this metal bearing here and there is a central pivot along which the polyethylene will rotate. Or secondly more like the biomet zimmer Oxford unicorn learning. There is a meniscal bearing, so there is a mobile meniscal bearing which allows for some uncoupling of rotational and translational forces. The second implant design is a medial pivot design in this. The thought is that the medial articulation between the femur and the tibia is a more conforming articulation. It's more like a ball and socket joint with rolling all and gliding and all these forces occurring in a ball and socket fashion like a total hip hop class city. However, the lateral side is the less conforming design and some of that comes from the proximal tibial anatomy because in the proximal tibia. The medial side has con cavity? The lateral side has relative convexity. So there is more translation and sliding forces occurring on the lateral side. So this implant is designed to preserve a medial four ball and socket type articulation and increased translational sliding forces laterally. It's a little bit of lateral laxity. The third implant design that I'm going to discuss is an asymmetric design. And various companies like smith and nephew and Zuma have really taken this to the next level and built in a symmetries when it comes to the newer totally arthur plastic implants. So this is an example of a smith and nephew journey in which there are asymmetric distal federal cuts. And correspondingly there is an asymmetric typical polyethylene to preserve three degrees of virus at the joint line. So now you are putting everybody in three degrees of virus. If you're doing a mechanically align me with this type of prosthesis. But let's say you achieve automatic alignment and you're putting them in 57 10 degrees of virus at the joint line. And you put in this prosthesis all of a sudden you're building in three degrees additional virus into that because of the design of the prosthesis. So that really begs the question should we be making our alignment cuts specific based on the patient type and the implant type. Or should we keep that independent. The final design that I wanted to highlight is the by cruciate retaining design. Now almost all of us when we do a totally arthur plastic we are sacrificing the A. C. L. Some of us preserve the PCL. Some of us sacrifice the PCL some of us built in um some kind of congruence into the polyethylene so as to minimize the function of the PCL. But the A. C. L. Is uniformly sacrifice. However there are there is this iteration of the design from the 19 sixties to the 19 nineties and sixties. It was the gun's design in seventies. Coventry came up with the geometric design and the nineties townley came up with his design of a. My crew's retaining me. Now why do we care about preserving the anterior crucial ligament? Most of us think that the appropriate receptive function of a knee comes from their A. C. L. When the A. C. L. Is ruptured in an athlete they suddenly lose the ability to control their knee until the quadriceps develops enough strength. So if we were to take that into a knee arthritis model. If we preserve the A. C. L. For that patient maybe just maybe the patient won't feel like they're dealing with an artificial implant. They may feel like they have their native need and that's why we are thinking about this type of implant. Now when you look at these various different alignment variations or various different implants. We need to critically assess how they do So what are some important performance metrics. The first question we should ask is the Kinnah Matic question Are we truly restoring the Kinnah Matic of a Native me with a knee replacement surgery? I believe the answer is no. But there is some evidence showing uh some some some type of uh data that people may get some cinematic benefit by performing alignment specific operations. The second thing is, can patients walk climb stairs, perform their activities of daily living better. And most importantly, do they have a forgotten joint score that is high, so higher. Forgotten joint score means that you forget that you have a protruding out of plastic. And finally, what is the effect of the implant and bone longevity Alignment variations, putting an implant in 10° of virus? What does that do to the actual polyethylene and what does that do to the underlying bone. So these are some things we have to critically assess for the various different implants that I mentioned and the alignment types that I mentioned. So, first off before we think about the Kinnah Matic of a totally replacement. Let's consider for a minute from our basic anatomy lessons. What is the native need doing, what are the forces along a natively, as you can see, I have a knee model here. Most of us were taught to think that the knee is just a flexion extension device. It's more like a hinge. But now we note there are rotational forces. There are translational forces. There are compression distraction forces. So, as you can see here, there are three translational axes in a knee replacement or or native knee, anterior, posterior medial lateral compression distraction. And there are three rotational axes, flexion, extension, internal and external rotation and virus and Vegas. So let's look at different positions and telematics and different types of activities that we frequently do Well. First off in the asian population, deep flexion is considered to be absolutely paramount. So most patients are asking can we preserve deflection? Well, in deflection, what happens is that there is more posterior translation of the lateral femur compared to the medial femur. And a net result of that is that there is external rotation of the femur, an internal rotation of the tibia in gate and gate. What is most studied is the stance phase. When you're standing there is more anterior translation of the lateral femoral and medial. Several candles and that's equal during flexion and there is poor syria translation during extension. So now there is a paradoxical shift compared to deflection. Why this happens is because of the ground reactive force. So this is Newton's third law to every action. There is an equal and opposite reaction. So if you're putting your foot on the ground, all of a sudden the rotation of the female relative to the tibia changes because of the ground reactive force unless you're floating in a swimming pool or in space stairs. How do we do with stairs. And in this, most studies have looked at going upstairs. Very few studies have looked at going downstairs specifically for the knee and what people have found is that there is equal translation anterior lee of the lateral federal con dial and the media ephemeral conduct. Sitting down and standing up from a chair or from a car is similar to deep flexion and extension running. How do means doing running? So again, low speeds have been studied, it's very hard to study someone like Usain bolt who's running that fast because our sensors are not that precise in running at low speeds. There seems to be an anterior translation of the media ephemeral content compared to the lateral ephemeral content during flexion reflection part of running. But this is dependent on how fast people run and how much of a slope gradient they have, whether they're going uphill level ground or going downhill. So as you can see this is mind boggling. The amount of complexity that anne has is mind boggling and we have just scratched the surface. Total knee designs need to account for all these variations and account for this complexity to give you a satisfactory implant. So right off the bat, we are facing a very uphill task of designing an implant to come up with all these variations in Nikkei automatics. So let's look at how can a Matics are restored or whether they are restored or not. So this was a japanese study which looked at cinematics and contact forces with computer simulation. They had three models. First was a mechanically aligned totally. Then was a three degree Kinnah Matic lee aligned. So more of a restricted can automatically aligned. Total meat in which the femur was in Vegas and internal rotation. The tibia was also in virus and internal rotation. And finally there was a five degree outlier. Let's say you you cannot align it within the restricted Kinnah Matic and you have an outlier then that's what they considered a five degree Kinnah Matic alignment outlier. And they used a cruciate retaining implants. So you kept the PCL in that implant. And as you can see here, the top row is the mechanically aligned model with various degrees of flexion and the bottom two rows are the Kinnah Matic lee aligned model. Read em is medial blue, L. Is lateral. So as you go through flexion and a mechanically aligned model, there is actually some internal rotation of the female in a dramatic airline model that seems to be matching the native cinematics of the need, in which there is more translation mysteriously of the lateral femoral Cornell compared to the medial federal conduct. So at least that seems to be restoring the native nick aromatics. However, because of the femur internal rotation and Valdez there is potential normal tracking and lateral tilt which occurs with a cinematically aligned model as you can see with the various degrees of flexion going down these panels. So maybe the patella femoral joint is not doing too well. What about the contact stresses? Well, this group also looked at that and they found that they were greater lateral patella femoral contact stresses early inflection in a cinematically aligned model. So these are again mechanically aligned, three degree Kinnah Matic and five degree Kinnah Matic. And these are contact pressures. Red being the highest pressure. And you can see that there is more pressure in the Kinnah Matic lee aligned me early on and then in the mechanically align me with deep reflection. What about tibial stress is so again you can imagine with a greater virus tilt of the tibia. And if the patient has a virus deformity, if you preserve that virus deformity all of a sudden you're going to see more forced through the medial aspect of the implant. As you can see in the Kinnah Matic model in the mechanical line model. The importance is that that balance is kept intact. So there are more normal nuclear matics but increase in plant forces because of this enigmatic. Uh Now what about the mechanical alignment? Does that have reliable patella? Federal Kinnah Matic. So this was again child's study that he said, you know what if you have mechanically alignment. Does that mean that patients uh and they have the patella results, do they have anterior uh them mechanically communication. Which anti unique and tell a motion is realizing is becoming complex because it's wisdom. A lot of different implant clients have different geometry and control the soft tissue restraints. So I think we still have some feedback. Um So the consideration is that should we look at the still camera joint lack of liquidity or DS Jlo to consider how the federal joint problems. So Charles looked at this and what he found was let's imagine four different patients with different kinds of joint line of liquid because of the performance. You have values six degrees degrees neutral and then three degrees about this is going to be your temple card with a mechanical you also look at the whole Syrian several parts you can how you realize you're a really good external rotation for all occasions between the posterior and destroy the middle class. Did I take a look? We have a long feedback one as the distal femoral joint line of liquid value just tends to increase. There used to be excessive of the lateral patella femoral compartment. So that seems to be overstuffed, which then leads to a video meeting. However, people semis your federal court based on the actual joint climb a the mathematical principles and then actually a you will have a achieved with this certain joint line of equity. And that will give you that point again, these are computational models. The real effect of patients is yet to be analyzed Here is another group that looked at Kitimat was mechanical alignment and they performed a systematic review of McCann Alice. And what they found with these first plots is that you can see the diamond cables, automatic alignment on the right side, tables mechanical alignment on the left side and zero perfect process. zero which means there is no statistically significant difference. If it doesn't then they're needed. So in the first part flexion that they can dramatically line me seems to increase the range of motion seems to be better. What does that translate into a regional advantage? We don't think so because that seems to be all over the place. Okay. Oh right now imply more different plans that I have discussed. Are they going to be better in terms of the story cinematics? So let's look at that, let's look at that. Yeah. Yeah. Yeah. Thank you. Uh huh. It is really needed is going away. Um you know give me there is a lot of internal rotation during deflection and there is a little bit of translation. With a rotating like on design that we're noticing is that there is all about 7° of rotation. Not 10-15° that normally occurs with the table. Internal rotation but it's still better than a fixed bearing design In which you only have four or 5° of rotation. So there seems to be some advantage of preserving the rotation. Yeah. Now what about rotating from designing revision Ritter's group looked at this in Indiana and what they found was that a rotating platform design results in 40% less micro motion at the implant cement interface and hopefully that results in better in a matics and survival of revision in plants. And I think again the data is relatively new but at least there is a theoretical benefit to this principle. How about using a cruciate retaining versus a posterior stabilized design? There seems to be no difference when it comes to cinematics. They seem to be equally preserved if you're using a rotating platform design cr or PS with stair climbing. So there is some functional advantage to that kind of design. Look at the medial pivot. So the medial pivot again immediately it's tight laterally. It is loose. That's what the native knee feels like. And many group in indiana looked at this using a cruciate retaining and a cruciate substituting design and found that both of them behave like single pivot essentially if you do not balance the joint. So medial pivot they found by itself may be too simple what seems to be happening in knees which have an intact a cl. Is that early on there is lateral pivoting and later on there is medial pivoting so it's called L. L. M. Early lateral late medial pivoting. It's a dual pivot mechanism to a knee which seems to be the most favorable the opposite which is early medial pivoting and late lateral pivoting seems to be the least favorable. So using these this concept what he said is I'm going to use a C. R. A. C. S polyethylene, a single radius implant design. Um And I'm not going to worry about the status of the PCL and I'm going to put this in with the smart tibial trace. It's called also sensor in which you can assess the pressure and we're going to see how the pivoting is going to behave. What he found was very humbling that in a minority of patients you could get the early lateral late medial pivot. In most patients you've got other Kinnah Matic pattern. So that seems to be very difficult to predict if you're going to put in a medial pivot need how it may end up behaving. What about gate? How do people perform? So Professor Haddad uh in England look look at this and he performed a gait analysis comparing single radius cruise ship substituting or sacrificing designs with a medial favorite implant and found absolutely no difference in various different gait parameters. So in terms of gate and in terms of function designs like a medial period are not seemingly offering any kind of functional benefit to patients. Now let's look at a symmetric designs in which you can have either distilled seminal cut, asymmetry, approximate tibial implant asymmetry or both. And in this this group in Italy compared to symmetric versus asymmetric design in mobile bearing total geese and they looked at stresses compressive stresses shear stresses and material stresses and what they found was that asymmetric designs overall in green leads to lower stress is in things like gate and in squad they're not necessarily statistically significant. But overall seems like they're offering favorable stress transfer to the tibia. Which is what we care about. How about the bike cruciate retaining design. So by cruciate retaining design, um it's important to see how that compares to the native me. So if you get it on one side does it feel like the knee on the other side? So this group in Korea compared or south Korea compared a native me to a cruciate retaining me which is keeping your official. Then they compare it to a standard by cruciate retaining me and then a patient specific by cruciate retaining me. So this is a customized by cruciate retaining me and how do they perform? So these are the images from that paper and what they looked at was get and deeply bent. So indeed what seems to happen is that there are similar killer. Matics between the native knee and a patient specific my cruciate retaining me. So you cannot just take a standard off the shelf. My cruciate retaining me and hope that it functions like the native me. No, you have to make it very specific to the patient's native anatomy. How about deep knee bends? Again, there seems to be similarity between the Native me and a patient specific by cruciate retaining me and not a standard implant. So if you're going to do a buy crucial retaining me Now you have to invest in getting a patient specific model made from imaging? Most likely a ct scan and then send it to the company and have customized patient specific jigs to implant this prosthesis. Another group in japan looked at high flexion activities. Again important for the asian population. And what they found interestingly was that in a bi cruise ship retaining me we were able to get or they were able to get medial pivot which is the early lateral late medial pivot type of dual pivot mechanism which seems to be so favorable. And that makes sense if you're going to preserve your racial you should at least get the functional benefits of the racial. Now what they also took this to the next level and they said how about we take a bite cruciate retaining design and we add medial constraint into it like a medial favorite design. Is that going to make the Kinnah? Matic is better? And lo and behold they found that so preserve your racial reserve your PCL and then add some medial conformity to your implant. And all of a sudden you have a bike cruciate retaining prosthesis that functions a lot like your total like your natively. Now what about laxity? You know the biggest problem with a bike cruciate retaining design is postoperative stiffness because we still don't understand what happens to the A. C. L. And the PCL in arthritis do they become stiff? Do they become loose? What happens to the other ligaments? We know that some of the other ligaments become tight. So what our last city in my cruciate retaining retaining totally. So this is a study from Belgium in which there was a categoric model in which they looked at various values laxity with flexion and compression distraction luxury. Also reflection. And what they found the blue bar. The blue line is the native uh me and the diamond is the bike cruciate retaining me. So the my cruciate retaining me in various degrees of flexion. Both in terms of virus Valdez laxity and compression distraction seems to be the closest to the native needs. So there is some similarity between these two models. The other models which is the cruciate retaining and the my cruciate substituting. These seem to be completely different and completely uh you know unreliable when it comes to how they perform compared to the need of me. Now the important question of the most important question is does a unilateral totally or you the lateral my cruise ship retaining me behave like the contra lateral native need. Is there a similarity or is there a difference? So the verdict is with the various different degrees of rotation and translation. These black bars indicate differences between the red lines which are microchipped retaining and the green line which are native needs? The black bars are pretty big except for superior federal translation in all other cases a native me and by cruciate retaining totally behave quite differently. So they're not exactly the same and patients may still end up feeling a difference. The only lateral late medial pattern and the dual pivot pattern is only visible in about 50-60% of patients in a my cruise ship retaining totally house not another patient. So again, there is a limitation to this design. This implant design that we still do not understand now. What about muscle activation? So if you preserve your A. C. L. And if it truly gives you the appropriate receptive advantage, the thought is that you should be then recruiting less muscles, Less of your quadriceps, less of your hamstrings to stabilize the knee because you have an intrinsic stabilizers in the knee. So what about muscle firing patterns when you're walking in using a cruciate retaining design versus a by cruciate retaining design? The thought is that by cruciate retaining design should activate fewer muscle groups. And that seems to be the case. However, not in level walking in level walking, the muscle firing was the same whether you use a cruciate retaining or by cruciate retaining design But downhill walking, recruited less muscles across the board when it comes to your master's. Media lists your rectus, your biceps, all your 17 Nanosys across the spectrum. They were activated less for my cruciate retaining me walking downhill. So this may be important for people living in mountainous areas and when you look at that, you know, the traditional patient in the United States may want to get out of their car, they want to run, they want to go to the local fast food or grocery store but it's more level walking. But if you look at patients maybe in Himachal today, sure. Switzerland they have to do a lot of the mountains going up and downhill and then there may be a functional benefit to using a bike cruciate retaining me. So that brings us to the million dollar question or the million rupee question is natural cinematics equal to good function. Can you restore function by restoring the cinematics or is there a gap in that. So Professor Howell in the United States looked at his outcomes and what he did is that he looked at his skin thematically aligned knees which were in the normal range that he had predicted Virus outliers. So people put in too much of virus and valdas outliers, people put in too much of algiers and he looked at their function, various different functional scores such as the Oxford score, womack score etc at 38 months and found absolutely no difference in their functional outcomes. So there seems to be a disconnect between their alignment and their function. Also. He extrapolated this data and looked at his tenure outcomes, whether they were in the range virus outliers, Valdas outliers and again found absolutely no difference. There is no statistically significant difference. So that makes us think, how do we align in Disney's and whether or not they're going to have any functional benefit? Yes, sure. You can say that their function is good but their function is also good with the mechanically align me so why should I be changing to automatic alignment? This is a paper from South Korea which again found absolutely no difference in function between Kinnah Matic and mechanically aligned knees with various different functional scores. And finally, this is uh meta analysis and systematic review. Again, looking at those forest plots, there is some benefit in doing Kinnah Matic lee aligned knees. When it comes to functional scores, people seem to have higher functional scores and range of motion for some of those cores in the other scores like a Womack score. Oxford knee score me society score that diamond seems to cross zero, which means there is no statistically significant difference between mechanically and thematically aligned knees. So there may not be a true functional benefits. Now, this is an award winning study from new Zealand that was presented at the knee society in 2016 in which they looked at Kinnah Matic lee aligned knees versus mechanically like these and found, you know, various different functional scores. They looked at various different function scores and found absolutely no benefit at two years. Absolutely no difference, whether you did a good Kinnah Matic area or a good mechanically aligned needs. So absolutely no functional benefit And the forgotten joint score was also the same. The exeter group shows the same thing. There is no functional benefit. When you look at all these various scores, european scores time up and go to minute distance tests. Absolutely no difference whether you do a planned Kinnah Matic or planned mechanical. Now, if you extend this and let's say that you don't follow your plan, uh even correct people's in the functional scores. So there's some disconnect between putting money. Where do you think it is and then achieving the function that you want for that patient? And that's what we are most interested in. How about a rotating platform design? Does that lead to good function? So, these are studies which looked at a cement lys, rotating platform design and a cemented rotating platform design and found that they are equal. They found that overall patients seem to look pretty good. And if you look at the functional scores, the numbers, the raw numbers, they are similar to a kid thematically aligned. Can do. Excuse me. Um But with the rotating platform designs, there is still grinding, there is still popping, there's still clicking. So patients still feel like they have a mechanical implants. They don't feel like it's natural, it's not how a native behaves. So there is still a limitation and patients still report report there is trouble getting out of a chair, there is trouble. Uh You know with some of these mechanical symptoms in a knee replacement. Now, what about medial pivot designs in medium pivot designs has shown here in this graph. Um, age have said that most of them have felt that the knee felt to be normal the other design. So the non medial paper designs, fewer percentage of patients that need to be normal. So there may be some benefit in having that medial constraint. However, when you look at the various different functional scores again and that the feeling of a knee being normal does not make somebody more or less functional. I think that that is a higher level of understanding that we don't yet have about how many functions. Dual pivot pattern again seems to be very similar to the Kinnah Matic of a native me. But functionally there is no difference once again in the school. So that is frustrating for all of us that either do these studies do this. Uh, do these surgeries or look at the literature because if you don't have a functional benefit, why should you change what you are doing now? Here are some other papers in in Toronto in Canada which looked at this vaccines group and they said that you know, there was a slight favor towards the medial favorite design. Some patients seemed to like it better for some of the activities that they were doing with regards to asymmetric designs and asymmetric insults. There is only one study out there. If you read the literature and the function seems to be equal when it comes to symmetric versus asymmetric insults. Again no functional benefit. And when you when you extrapolate this data to buy cruciate retaining designs again there seems to be a similar joint awareness. So uh you know whether patients notice that they have a bye cruciate retaining or cruciate retaining really doesn't seem to alter. What seems to be important for a by a cruciate retaining design. Is your post serious slope if you make a mistake and put into much more serious slope for these patients that seems to lower their A. C. L. A lot more and can result in a cell rupture which then leads to a poor functional outcome for these patients. So it's critical to pay importance to their design. Now. What about a custom by crucial retaining design? So this is a paper by Professor Beckman's group in ST card in in Germany and what they found is that they have pretty good outcomes with a custom patient specific by cruciate retaining design. And they seem to have pretty good functional scores as well. The functional scores are also related to the forgotten joint score. So this is another paper out of Germany in which they looked at joint forgotten joint score if you have a higher forgotten joint score. That means that you have forgotten you have a prosthesis. So they compared a bike cruciate retaining design to a standard posterior stabilized totally to a unique antler total or unique. Unlearn er three plastic partially replacement and what they found was that a bi cruise retaining me and uni seem to have similar forgotten joint scores but a posterior stabilized totally seem to have lower forgotten joint scores. So there may be some benefit in forgetting that you have a totally replacement. If you use some of the newer designs or if you apply Kinnah Matic principles such as a unit and there is a thought professor Justin calm in the United Kingdom he picks doing a medial unique then a patellar ephemeral and then a lateral unique over doing a total knee replacement. So there may be some thought in preserving the native architecture of the knee and just resurfacing the arthritic surfaces instead of replacing the entire knee. Now this was uh systematic review that we performed on my crucial retaining needs. And what we found was that overall the kingdom attics are similar to the native knee. There is superior, appropriate exception from the A. C. L. Compared to various different other types of total needs but it is technically challenging. It's unreliable on how we perform these procedures and functionally you're no superior than a crucial retaining total. It is a difficult surgery but not necessarily validated in terms of functional outcomes. The far uh we have to assess is how does the underlying bone perform? Are we creating revisions for us down the road by either switching our implant designs or switching the way we align them. So let's look at the automatic alignment survival At short term follow up. People have looked at this, there is excellent survival. There is almost 98% implant survivorship extending it a little bit further. Uh You know, different groups have shown that again, it's 97 to 98% survival ship in this short term. Now. What about long term or medium term survivorship? So this is dr howells group once again who has the most data of this? And what they found is that At five years to 10 years there is really 98% survivorship. When you look at revision for aseptic loosening. If you Mala line this if you put this in too much viruses, they're going to loosen over time. Really, the revision rates are not existed there only one or 2% which is comparable to a standard mechanically align me. So patients seem to be doing really, really well when it comes to these implants. What about short term functional outcomes? Is there any difference? So this was again a systematic review and meta analysis and there was really no functional or survival benefit to performing one versus the other design. So in the short term both alignment designs seem to be just fine. This was the same study. The New society Award winning study from New Zealand which also found absolutely no difference in survival rates and revision percentages for Kinnah. Matic versus mechanical. So at least we can say that a kid automatically aligned me is not performing any less than a mechanic. Realign me so at least there is no inferiority. There may not be superiority either. What about rotating platform designs In this group? Whether you use a cement list designer or cemented design at 10-20 years, there seems to be excellent survival. So rotating platforms are tried and tested and you can use this. You may not have that much of a cinematic or functional benefit but at least you can use them with excellent survival with regards to medial pivot. These designs have only been around for 12 to 15 years of studying for 12 to 15 years and again there is excellent survival at that time frame in a symmetric designs. A lot of implant companies have introduced us. There are newer studies coming out. There are really no medium or long term survival studies. So we have to be a little bit cautious whether or not preserving that three degrees of joint line virus makes any difference. And if you think about it, let's say you have a patient in 10 degrees of elegance and all of a sudden you do a mechanically aligning and put them in three degrees of virus with this type of implant. Are they going to be happy or not. Finally, with regards to my cruise ship retaining survival in the short term people have said that there is very good survival almost 98% at two or three years. And patella revisions seem to be the most common because the extensive mechanism seems to be stressed if the A. C. L. Is not functioning like it should higher. Re operation rates do exist with my cruciate retaining probably because of technical challenges associated with preserving both cruciate ligaments. However, some studies are more humbling with an 88% survivals, almost 12% failure rate at three years. And that's a pretty high failure rate. With a newer implant design to be a loosening seems to be the most common issue for revision in some of these by cruciate retaining designs. So again making sense because it's technically a more demanding procedure for those patients. So in conclusion, what I want to state is that native nick aromatics are very complex. And if you try and use a totally replacement and try and restore these aromatics, it is even more challenging. And I don't think that we have an answer yet the aromatics are not correlating with outcomes necessarily. And just like the previous generation, there were debates whether or not to resurface the patella whether to use CR designs or PS designs. We don't have a consensus on any of those debates. I think that the debate of this generation is going to be automatically aligned or mechanically aligned. There is no clear cut winner. They are equally Losing uh in this race against finding why 15% of patients are not happy with their totally replacements. And I think because we don't understand the complete function of the knee, we are unable to reproduce it with a totally Arthur plastic. And again, also in terms of implant designs, there is no clear winner as long as you use a good tried and tested in plant and you apply it with your surgical technique, paying attention to how you apply that implant. I think that you will have a winning combination. So I'll show you my personal bias. You know, I get a lot of these deformity cases which obviously in India and other asian countries and developing countries. We tend to see patients who have neglected this for a very long time. So I will either use a large console or small console navigation and aim for a neutral mechanical access because such a deformity. If I try and preserve the aromatics, we have already seen that the need of anatomy has failed. So the Kinnah Matic alignment will likely fail as well. And I am yet to see papers looking at kayla Matic alignment in such type of deformities and addressing the deformity and the patient function. So I am these are the two year follow up x rays for this patient and as you can see I've restored the native the neutral mechanical access And there are pretty large polyethylene components because of the soft tissue releases that we have to perform to align patients um into their mechanical kind of framework. Um And this is the lateral X ray two years the implant to survive. I have used un cemented tibial stems for this patient because of the increased forces that the patient will see as you release the ligaments. Um And you know the release the ligaments may tend to go back to their native position. So we want to protect against that aseptic loosening risk. And this is a video of the patient just before her surgery as you can see here holding onto the edge of the stretcher. Not being able to walk, not being able to cook, not being able to do anything for herself or her family. And these this is the video of her walking at two years. Post operatively you can of course argue that she has a stiff gait because of a mechanically aligned me. But at least she's able to walk unassisted, Able to stand able to perform the functions her activities of daily living with a good amount of satisfaction. It may not be 100% but it's close to that. Well that any questions that you may have. Yes. Thank you. Thank you Doctor Service Ashitaka. Uh This topic is a little. Yeah. Can you hear me? Can you hear me? Mm hmm. I can't kill you gordo can you put on your radio. Yes. No. Can you hear us? Yes now I can hear you. Yes. So we also I would like to introduce welcomes newcomers and pray most office practice is in our practice. He's uh he's uh he's operating from Aurangabad. He has his own hospital and he's gonna be dynamic guys who does after plastic for everyone since the beginning of the practice. But now we have come to know about him in the last five years that he's gonna be at the plastic with that area. Okay, so you want to start? Yes. Can you ask some questions to him regarding the topic? So what is his uh current twice of implant? In a moderately deformed me? After hearing about the implant? Almost every implant is doing the same. So what is his current personal choice in a moderately deformed me? That's a fantastic question. Thank you very much for asking that. You know, I I am a believer still in the mechanically aligned model or restricted cinematic. And I will use uh you know, if I could name a company, it will be a few uh deal with the possibility of increasing my constraint. So sometimes the cartoon, you know, is only limited to C. R. And P. S. Now the revision of tunes are coming with increased level of constraint. Sometimes in those cases I will use the two sigma uh like a zimmer CC. K. Which offers me various different levels of constraint. And I'll start with the lowest level which for me is a P. S. And then build up from that. So you're not cr uh for the sacrifice the cruise ship it's a very big yeah. You know because I don't, the biggest issue that I have found is I don't know what the cruise ship engine should be No one. and it's difficult to balance that and if it's an arthritic knee then what what happens with that? So you know in my training I kind of learned that if you are a cr person, nothing wrong with it. But you may have to deal with some cases of postoperative stiffness. And if you're a ps person you may have to deal with some cases of postoperative instability. Uh huh. So you have not shifted yourself to kanna Matic alignment yet as I understand, not completely. I am of the belief that I want to restore Kinnah Matics with the implant. So if I'm going to see somebody in a virus deformity a 5 to 10 degrees, I may perform sleight leases on them. I may use the symmetric implants like smith and nephew journey or a Zoomer persona. And please. Uh Okay now one thing that has helped me is that for every meal replacement patient now or for every every patient that has a hip or knee problem I'm getting long like images all the way to the pelvis and that has tremendously reduced how many releases I perform because if you just look at a magnified stray off for me sometimes we tend to think that wow this is a lot more virus. So this is a lot more val guest and all of a sudden we are tempted to release a lot more. So now I'm being very uh very conservative but how much ligament really have to be. Yeah. What this was uh have you ever done the kinda medical let me in the valley Disney do you perform or is totally in those cases I still believe in performing a mechanically aligning. I have not done it in analogous knee. Um And I haven't really seen much literature focused on that but honestly for the Kanneh magic me, how do you take? The camera is perpendicular to the building? How do you perform first then how do you go to the kind of. Yeah so there are different you know devices that come so you know you can you can look along length X rays and aim to restore their distal femoral joint line of liquidity. You calculate that out based off your mechanical access and you can adjust your uh if you use some of dr howells jigs, what um they are based off is the amount of where. So the jig is set based on whether there is medial sided wear or lateral sided wear and they have shims that come on to that which you literally placed on the bone and then you put your pins in and make your distal femoral cut based off. Uh you can also use navigation based on your preoperative planning and say that this is what I want to cut it and make sure that you rely on your navigation system uh to that. So there are various different ways of making a cut. Um You can also base it off the tibia but frequently you know we are cutting the female first so I'm not relying on the tibia. Um To base my restricted Kinnah Matic airline needs. I'm cutting the female first. He's officially leaders in case of Panama. Yeah. So what about some tissue releases? You know when I when I you know did cases where Charles olivier. It's it's interesting you still end up releasing the deep fibers of the M. C. L. On the tibia to get your medial exposure to make their cuts. So I think that that tends to happen. Uh But then the rest of the soft tissue releasing in a pure Kinnah Matic model, they're not doing it. Um Some of us who are the restricted Kinnah Matic folks, we will do a little bit of pie crusting. So I think that we still are accounting for some type of contraction and releasing that. I was just going through some literature inverse kind of. Do you have any? I don't no no I don't. Yeah basically in that they said that they respect the middle and reception of the middle and like political content is the same identical who maintain the joint line implicated. Then the Middle eastern funeral dissection has to be the thickness of the femoral impact and the best local parents. Thanks. And at the close of the medial tibia and obviously there is no soft tissue released. That's quite different from the dynamic together. Yes. So what I understand from your talk is that kinda Matic alignment is still not catching up. It has not fully caught up. And uh for routine knee replacement with as a doctor Sheikh Omar's and tasked with routine mild moderate deformity. Uh The basic implant like an itunes without should be good enough without using the econometric alignment with a basic navigation. Am I understanding right? Absolutely. Because you know, I think that there are a lot of uh the there is uh between uh I have the latest technique but we forget that for that to really be applicable. There has to be a functional benefit. I and a lot of people world over are not finding that much of a functional benefit just yet in the literature. Maybe it's because we are not sensitive enough to detect this this difference. So we just have to be cautious. Uh And I agree with you. I think that as long as you follow sound techniques, whether you're dprk automatic restricted or mechanical and you have an implant with a good track record in your hands, you will end up with 85 to 90% success. And we're still working hard to figure out the last 10 to 15% of success. Uh Gotta go ahead. Go ahead. How do you basically can simplify going? Let me make sure you go for the final meeting me for this new invention when we go for the mechanical element for the other me. Yeah. So for me, the cut off is um, you know, 5-7° of joint line of equity. If there is more than that, I'm going to chemical whether it's virus or value us. Uh, and then if it's virus, I am performing some uh on strip me, I will then perform artistic hospital actually. Um, and around and then I will put in a uh, standard implant. Like a symmetric implants if they are more than 5 to 7 degrees of virus or Valdez um, you know, I just can't do that if they are less than that didn't bring restricted Kinnah Matic alignment with a standard, not with a modern implant. And uh huh. You know what that will do to their alignment. You said something about immediate towards and going to get done the video johnson through shared back and returning in class that I think were not available in India. Yeah, it was briefly explain about the middle uh to your new music with various places. Usually got some severe cases. Uh Yeah, So, you know, that's a great question. So I think that some severe cases where I'm doing a mechanical alignment and I want to reduce the level of constraint. Like I am applying to the implant by not going up, you know, in terms of PS two CCK but then I'm giving them medial stability with that medial pivot implant because it is more like a ball and socket joint media. You know, it's a lot of conformity immediately so it's stable there and laterally there are some sliding forces. But as long as you balance out the medial side of the knee, you will have a stable me which will not dislocate or subluxation, basically it's like a constraint on the media sector. Exactly like less than we need to put in the rod in the tibia to stabilize it. No, you don't need to, you don't need to put in a stem in the tibia to stabilize it, correct? No. Sure. Yeah. Yeah. You know a lot of the plants, newer generation implants are obviously more expensive, technically more demanding. So I think that that update has not happened uh in many places. Uh and you know, even the smith and nephew, my cruise ship retaining in plan, which is probably the most common one. Now it is going out of favor because I think for the ultra plastic surgeon um it may be easier to do a medial unilateral unique and then a patella, federal, whether you do it in one setting or multiple different settings. If it if it means uh than to perform this micro retaining, that seems to be more challenging package. Mhm You know, I think you're muted. Michael Newton. Thank you. Thank you very much. Thank you, joseph, joseph. Thank you. Doctor Goro, Kennedy and thank you Dr Sukumar Century. And we thank uh also Tv and we thank GSK consumers, the makers of biotechs gel to bring us this webinar. Thank you very much and good night to everyone and good day to you sir. Bye bye. Yeah.