Minimally Invasive Knee Replacement

Hello. I'm Dr. Randale Sechrest your host for eOrthopodTv. Today, we'll be talking again with Dr. Craig McAllister. Dr. McAllister is an orthopedic surgeon who practices at Evergreen Hospital in Kirkland, Washington. Dr. McAllister did his medical school training at the University of Washington School of Medicine. There he completed an orthopedic residency at the Albert Einstein College of Medicine. And from there a fellowship in hip and knee reconstruction at the Cleveland Clinic. Today, Dr McAllister practices knee and hip reconstruction and focuses on minimally invasive surgical techniques for the knee and the hip. Dr. McAllister is also the President of Opertiv. Opertiv is a company that designs and manufactures instruments and teaches surgeons how to perform minimally invasive surgery using computer navigation techniques. Dr. McAllister has trained more than 200 surgeons in minimally invasive surgical techniques on the knee and has trained more than 200 surgeons also on the use of computer navigation. So, thanks for joining us today Dr. McAllister.

Dr. Craig McAllister: Well, good morning. Thanks for having me.

Dr. Randale Sechrest: Well, Dr. McAllister, what I thought we would do today is talk a little bit about minimally invasive surgical techniques. Especially as referenced to the knee replacement. And what I'd like to discuss is your experience with this technique and how you see minimally invasive surgical techniques impacting orthopedic surgery and especially when it's used to perform knee reconstructions or artificial knee replacements. So, let's start out by just giving us an overview of your experience with minimally invasive surgical techniques in the knee.

Dr. Craig McAllister: Well, to start with, Randale as you know, I was really trained with more traditional or standard knee replacement techniques and did use those techniques consistently, all the way through the 90's and really into 2002, 2003. Right around 2001, we got in a special interest group of surgeons across the country who, while they were very happy with traditional knee replacement techniques, were also frustrated with some of the elements of traditional knee replacement. Including the size of the incision, the amount of pain that our patients typically had after their surgery, the length of time that it took for them to rehab, and while it was really considered a very good operation, some of us really got involved across the nation in developing new minimally invasive surgical techniques. So, basically between 2000 and 2003 we got involved with it in the lab, really developed new instruments, smaller, down-sized instruments, went all over the country looking at different types of minimally invasive surgical techniques and then as we prepared to change our methods in the operating room, started accumulating data comparing range of motion, and pain, and length of incision, and blood loss and some other things in preparation for a publication. Then in 2003, we, in January 2003, we changed our technique to the minimally invasive, kept our data, published our results, and really have never gone back to traditional techniques.

Dr. Randale Sechrest: Lets talk a little bit about how these new minimally invasive techniques actually differ from the standard techniques. Can you take a patient through what's different about these two techniques?

Dr. Craig McAllister: And of course it's always a little bit difficult to have that conversation without getting too technical, and I apologize for some of the technical elements, but I think even for patients to truly understand the difference, it's valuable to hear just a few words on traditional knee replacement techniques.

You know when knee replacement was being developed in the 80's and 90's and even up to 2000, people were all about using instruments that were reasonably large sized instruments that needed a pretty substantial exposure in order to do the operation well. There was also a tremendous amount of emphasis on getting the implant in in proper position. In fact, really by 1990, what really defined a good quality knee replacement surgery was the ability to get this really impressive exposure of the knee. And to get that exposure pretty much all of the incisions were 12 to 14 inches, we rolled the quads mechanism up and out of the way in order to get exposure to both the, all the major bones in the knee. We virtually dislocated the tibia away from the femur in order to again get this big exposure doing large soft tissue releases, and by the time we were done, and again we did pretty much every knee the same way, but by the time we were done we had this large exposure to the knee that enabled reasonably bulky, large instruments to be used to get these implants into the proper position. Again that was the gold standard of the procedure, and nobody really thought too much about this big exposure. Because what we were after was the 10 and 20 year result.

Minimally invasive surgical techniques basically say, well maybe we can get those implants in, in the proper position, and maybe we don't need to have this big exposure for everybody. And with modifying the instruments and modifying the surgical techniques, minimally invasive surgical techniques can safely be done in the knee.

Now, Randale, you know that there are a lot of different types of minimally invasive surgical techniques. They are popularized on the Internet and on television. But all those minimally invasive surgical techniques basically have three things in common. One is they protect the quadriceps, Instead of just rolling the quadriceps out of the way, and the patella and the entire extensor mechanism out of the way, we keep it in place. Two, we don't dislocate the knee – the tibia rather, out from underneath the femur. And the third element is that these small down-sized instruments are used in concert with a mobile soft tissue window to access the different parts of the knee that we need to, and to be able to do it sequentially and actually capitalize on some of the maneuvers that we do to reduce the knee for exposure and put the implants in a safe position. So in a nutshell, it's just those three things. Don't roll over the quadriceps mechanism, don't dislocate the tibia, and use this mobile soft tissue window in knee positioning to minimize our need for exposure.

Dr. Randale Sechrest: We probably ought to explain for patients what a “mobile soft tissue window” is, and if you could, try to explain what that means.

Dr. Craig McAllister: I'm glad you asked that, because it is difficult to get a hold of. But, basically what I would say, in a nutshell, it's like instead of opening up the whole door, so that you can see the whole room at once, I give you a hole in the door and you get to move that hole around the door wherever you want so that you can eventually see every part of the room that you want to see. That's an analogy, put more practically in terms of knee replacement surgery, you know arthroscopists- people who do knee scopes - have been used to and accustomed to moving the knee around in multiple different positions in order to put the scope in where we want it, right? Well, the same is true with knee replacement, if we're willing to move the knee from a fully straightened position into a bent position, put it over into an angled position, in what we call a figure-of-four, all of a sudden we can now take the smaller incision and virtually have the knee move around a bit and get access t all the different places that we need it. Where as in traditional knee replacement we would historically, we would pretty much make an incision, make a surgical approach, put that knee up into one position and that's the position we would operate from the beginning to the end of the operation. And you can understand that when you keep that knee in one position you really do need a bigger exposure to get everywhere where you need to get.

Dr. Randale Sechrest: Well, I think that we probably ought to speak to what this really means for the patient and the surgeon, in terms of the advantages of the surgery itself. How does this translate into advantages for the patient?

Dr. Craig McAllister: Well, and I think it's very very careful to put that cautiously, because as you know, for most of the orthopedic surgeons in the United States today, the traditional measures with the larger incisions and bigger exposure is still the standard of the industry. And that is what 90-95% of surgeons are used to. So let's consider that the “gold standard”. With that “gold standard” we're used to
10 and 15 year results that are very good, we're used to implant positions that are tolerable. We're used to very reproducible results among all the orthopedics surgeons that are trained in this technique. So, the problem though is with that traditional technique is in that first year, you know kee replacement surgery is very hard to recover from,. There is a substantial length of stay, 8 to 12% of patients end up with knees that are stiff, by the surgeons standards as well as the patients. They have a very long time before they can get back to work, maybe even the first year or so. And in our study, when we looked at our traditional technique it took patients a full year to get their range of motion back to their preoperative range of motion, in terms of their ability to bend it. That ability to bend their knee predicts how soon they can get back to activities. For example you need 90 degrees to come downstairs, you need, rather you need 90 degrees to go upstairs , 98 degrees to come downstairs, you need about 110 to get down to your shoe. A little bit more, 115 to 120 to be able to site your put. So that range of motion strongly predicts when people go back to various activities. Well, it it takes a year to get that range of motion back, that dictates how soon people go back to work, how soon they get back to their recreation. How much time they spent in painful physical therapy. What minimally invasive surgical techniques do is allow us to do this operation, have less incision, less post-operative stiffness, they have a shorter length of stay, our blood loss has dropped from 32% transfusion rate down to 2%. And transfusion rates predict other morbidities, like swelling and fevers and other issues that happen. So in a nutshell, in our study what we showed was that patients were able to get their preoperative range of motion back at three months instead of one year. Our need to manipulate their knees post operatively to help their range of motion dropped from 12% down to 2%. Our transfusion rate as I said dropped. The patient's pain that was measured in the hospital by the nurses was statistically less then it was for the traditional group. So in a nutshell they come through the operation with less postoperative pain, smaller incision, less blood loss, less postoperative stiffness, and an early return to their functions. But again all of that is within the first year. The other thing that the study did show was that by one year after the operation it really didn't matter to the patient whether or not they had had a traditional techniques or a minimally invasive surgical techniques - except for the incision size.

Dr. Randale Sechrest: Now, you had mentioned the use of computer navigation, when we started this discussion one of the components of minimally invasive surgery I think is becoming the use of computer navigation to perform these operations. What do you get when you combine computer navigation with these minimally invasive surgical techniques, what are the advantages of that addition?

Dr. Craig McAllister: From my point of view, it's the perfect marriage. It's like the hold Grail. The surgeons that are legitimately continuing with traditional measures will tell you that one of the struggles of minimally invasive surgical techniques is that familiarity in the exposure and the feeling of confidence that they are getting their components in the right position without having to overly stretch soft tissues, without having to induce trauma on the wounds, and just getting enough visualization to that they feel comfortable to put the implants in safely. Well, computer navigation solves all of those problems. First, it guarantees the implant position because virtually every move that the surgeon makes including the final implant position is validated and verified by the computer in the operating room. Secondly, the use of the small computer probe to see where we're working and what we're doing and what landmarks we are using almost infinitely reduces our need for exposure. No more bulky instruments, no more having to just only sample one landmark to make sure we're in proper position, we can sample three, and use the best landmarks that are accessible. And lastly, as you know, with computer navigation we're not putting a rod down the femur, so there's a significant reduction in the burden to the patient in terms of exposure by not putting that rod into the femur.

Dr. Randale Sechrest: You know it's easy to see how different visualization techniques have changes our lives as orthopedic surgeons. I think you and I are both of the generation that grew up with the fluoroscope and the people that taught me did not have the ability to use the fluoroscope, so they were fixing fractures of the hip and things like that without the ability of seeing where they were putting instruments. So the fluoroscope was a huge step in terms of allowing us to see the skeleton without actually opening the skin and looking at the bone. Then the arthroscope came along and again we began to become very comfortable using the TV screen now to visualize in three dimensions what we needed to do inside that joint without actually opening up the joint. I think computer navigation is just another step beyond that. And for patients that are listening what this really does is give us the ability to see through the skin, to see the skeleton to see the landmarks without actually making an incision. So, we have a very comfortable view of the skeleton knowing we are putting instruments, knowing where we're aligning things, based on our computer image, rather than having to open it up and look at it and see the bones so that we know by our own sight that these implants or these instruments are in the right place. And like you said, that is just very difficult to grasp until you have tried to do this any other way. So, it's a striking advance in orthopedics.

Dr. Craig McAllister: Well, and of course, as you've described it there are considerable advantages to using computer navigation even if the surgeon isn't using minimally invasive surgical techniques. Some do minimally invasive surgical techniques a reasonable number of surgeons sue computer navigation, it's yet a smaller subset that are combining the two, and actually exploiting computer navigation to help reduce our need for exposure is really where that perfect combination is.

Dr. Randale Sechrest: Ya, I think we ought to let patients know too, there is a learning curve to this. Just like when you and I learned arthroscopy, or we learned to do things while looking at the fluoroscope, there is a learning curve there that you have to begin to conceptualize things in your mind, and where you are putting things. It's almost like trying to locate something under muddy water when you first start out, you can't see, you don't know where you're at, you don't know where you are putting your hand. But once you get used to it, it's a very powerful technique, but there is a learning curve.

Dr. Craig McAllister: And every surgeon that we've trained, very very few of the surgeons that we've actually exposed to and trained in computer navigation have actually gone home and been able to get the technology and start using it. But every surgeon that we have trained with minimally, with computer navigation rather, has really validated that it's made them a better surgeon. While it seems a little murky and a little confusing at first, having real time feedback in the operating room on all your steps is sometimes a little humbling at first. And all of a sudden you start looking at everything differently and so it makes us all a better surgeon, whether we introduce the technology into our operating room or not.

Dr. Randale Sechrest: Ya, I agree, I think that anybody that's every tried to learn to play one of the modern video games probably can understand what we are talking about. Learning that hand-eye coordination when you're looking at something that you're not really touching is a different experience, and that's really what we are talking about.

I think we probably ought to talk a little bit about the disadvantages of computer navigation and the MIS, or the minimally invasive surgical techniques. Because I think there are some disadvantages to these techniques. Can you sort of discuss a little bit about what you see as the disadvantages of these techniques.

Dr. Craig McAllister: Well, let me focus first and foremost on the minimally invasive surgical techniques rather than computer navigation, and from my point of view probably the single, biggest disadvantage is and really are all of the safety features, and safety elements of joint replacement surgery. And let me go back to my earlier comments. Traditional techniques with a wide exposure still today are the gold standard of knee replacement surgery. I once shared the podium with Richard Rothman of the Rothman Institute. An older surgeon, very skilled, very famous actually. And one of his points that he made is knee replacement surgery, the traditional approach, is one of the best operations done in the United States today. Honestly Randale, of all the surgeries that we know, orthopedic or non orthopedic, how many can boast a 15 year success rate of over 90 or 95%. So the traditional surgeons are saying why would we tamper with that result? Why would we compromise would management? Potential for fractures, implant positioning? All to get a better earlier return to function. An quite honestly I adhere to that especially when you stop and think about what a learning curve means to an orthopedic surgeon. It's not like trying out a new car that doesn't travel for you. A learning curve for an orthopedic surgeon can translate to complication rates, unhappy patients, longer lengths of stay, fractures, significant complications and in fact the study that I mentioned earlier was recently cited in a larger meta-analysis where virtually 50 different minimally invasive surgical studies were evaluates and one of the things that they showed was that there was a higher complication rate associated rate associated with the learning curve. I see a number of patients coming to me for a second opinion and they're asking about minimally invasive surgical techniques and one of the points that I make to them is, don't ask your surgeon, don't push your surgeon into using these techniques if he or she isn't 100% comfortable with it because there can be significant complications.

Dr. Randale Sechrest: Ya, I agree, I think you're right in the sense that you point out that when we're talking about learning curves, it's not just we make some mistakes, because every time we make a mistake when we're operating on a real patient, that does translate into some sort of a problem for someone, and it's usually the patient. So, increased complication rates, those sorts of thing, I think you're right in the sense of seeing that as a disadvantage. But, on the other hand, what is your argument against that for pursuing these goals, I mean there's got to be a trade-off, and where is that trade-off?

Dr. Craig McAllister: As you know, we've put a lot of time and effort into this. And I think the opportunity to do minimally invasive surgical techniques safely is there. As I said, there are a lot of minimally invasive surgical techniques, some of them really, some of the techniques that I think generated a lot of the bad wrap were what I call all or nothing events. The surgeon, it was a radical departure from what the surgeon was used to, and such as the two incision technique in the hip and the so called quad sparing technique in the , the sub vastus technique in the knee. These are techniques where the surgeon really virtually has to depart from what he's used to, and in an all or nothing moment, change dramatically. Also those techniques don't allow for what we call expansile measures. And you know what that means, Randale, it means that if I start off with a 4 inch incision, or a certain surgical approach, if I need to see more I can simply expand into a larger exposure. Our methods that we evolved and that we teach enable us to expand as necessary, Typically staying within what we call the definition of the MIS techniques, but if necessary, we can expand outside of that. Second, the techniques that we teach at Opertiv can be introduced and taught in what we call an incremental level. So, maybe on the first operation the surgeon doesn't evert the extensor mechanism, and after the surgeon gets used to that, he looks at whether or not he really needs to dislocate the tibia, and then maybe instead of taking the bone off the end of the femur first, we'll move towards what we call tibial first. In other words, it's actually our surgeons that come back repeatedly, talk about minimally invasive 101, 201, 301 and 401. So it's a much safer way of doing things. And then for me, the huge really opportunity that we had was that we do have our own lab, we do have the ability to virtually manufacture our own instruments. So we have been able to take this on a very slow, systematic and responsible way. And then lastly I would say that whenever a surgeon in clinical practice is changing techniques, that surgeon really needs to be focused and have lots of repetition and lots of opportunities to go and share experiences with other surgeons. So, one of the opportunities that we have is we're very focused on hip and knee replacement, so between the lab, the method, and the fact that this is our particular area of interest, we are able to do it safely, as was shown in our study. In our first hundred knees done minimally invasive, our complication rate, length of stay, all those parameters actually went down. It turned out to be safer than traditional techniques, but it has to be done in that kind of rigorous systematic way.

Dr. Randale Sechrest: You know, I think that I remember the time when these same discussions were being had about arthroscopy. You know, the same exact sort of discussion about why would you ever want to take a very tried and true operation as we see it today, and try to do it with minimally invasive techniques. For example rotator cuff repair in the shoulder. You know there has been a controversy over whether you could do those types of operations better, with a better outcome, with the arthroscope in an minimally invasive technique versus doing it the old fashioned open way. It was the same problem where you had a generation of surgeons that were experts at doing these types of operations open, and ya, if you said well, next week we're going to shift and have you do them with the arthroscope, obviously their outcomes were not going to be as good. But I think the bottom line becomes, today, no one would argue that doing a minimally invasive procedure in a lot of the things we used to do open, with the arthroscope is superior to doing it that way versus doing it in the open way. So there has got to be at some point, some argument that a minimally invasive total knee replacement gives you a better outcome for the patient once you learn those techniques. Now, is that your experience?

Dr. Craig McAllister: Well, and I think that's what we validated in our study. We were able to show that their range of motion was better, that their pain post operatively was less, that their blood loss was less, from 32% transfusion rate down to 2%. And that the manipulation rate – which to clarify what that is – if a patient is struggling with their range of motion, remember that we all accept that 8-12% of patients who have a traditional surgical approach, will have a stiff knee. And when their range of motion isn't progressing well, we take them back to the operating room, another anesthesia, and we bend their knee for them – and that's called a manipulation. It's actually always considered to be just one of the tools that we have in the proper post op rehab of a knee replacement. Well, our manipulation rate dropped from 12 to down below 2%. So the argument for doing minimally invasive surgical techniques – over and above patient comfort and earlier return to work, earlier return to their functions is the actual complication rate, when it's done properly, is less. No second anesthesia, lower blood loss, those are all very real complications after knee replacement surgery. So if we can a) get our implant positioned as good or better than traditional techniques; b) return our patients to their normal lifestyle with less pain, less physical therapy, and sooner, and: c) do it safer, to me that's a compelling argument.

Dr. Randale Sechrest: Well, I agree, and I think I would make one other comment. That is that through the years there have been a lot of different procedures that were developed by one or two surgeons, that those two surgeons were just exquisite at doing, and they could do that operation with an incredibly low complication rate and get results that were just amazing. But, they couldn't teach it to anybody. They couldn't get it to the point to where someone else could reproduce their techniques and reproduce their skill. What have you done in terms of what you're trying to do with Opertiv, to try to make that learning curve as easy as possible for the everyday surgeon to be able to acquire those skills, so that any orthopedic surgeon could acquire those skills?

Dr. Craig McAllister: Oh, that's a good question. Well, let me dissect the question a little bit before I answer that. You say 'any orthopedic surgeon'. The truth is easily over 80% of knee replacements done in the United States today are done by surgeons who do fewer than 20 knee replacements annually. And we need to respect that. Maybe the advantages that I listed in terms of rehab and lowering the complication rate and all those tangible, but not necessarily paramount priorities, right? Maybe those priorities aren't high enough for a surgeon who is doing 20 of these a year and knows very well haw to do traditional techniques and gets very solid results in his own community. First of all, maybe not every surgeon should switch right away. Because this is a new technology and it is a significant commitment and a significant learning curve. But what about the surgeon who who has a higher volume, who has a true commitment to knee replacement surgery per se. We've created a, we call it the “tree house”. It's a lab, we have a cadaver lab where that surgeon can cone once, twice, three, four, five – we've had surgeons, and we call them the iKnee surgeons, who have been to our lab a number of times, they've operated with me. We go out to their hospitals and operate with them and introduce these techniques in a safe and incremental fashion. They have communicated to us that they have been able to introduce these techniques in their own patient populations safely and happily. So I do believe that first of all the surgeon has to decide whether or not the commitment is there, secondly, visit our lab, spend the time in it, and develop the methodology in an incremental way.

Dr. Randale Sechrest: Do you think that this is what the role of Opertiv is going to be into the future? Of really training a set of elite knee surgeons who are in some ways the best of the best at using minimally invasive knee replacement techniques and using computer navigation to really provide this elite level of knee replacement?

Dr. Craig McAllister: Well, I might avoid the word “elite” and replace that with “committed” or “specialized”, because there is nothing necessarily elite about choosing minimally invasive surgical techniques over traditional. If a surgeon wants to do that because that's what the surgeon is comfortable with, I honor that, and they're just as good as the rest of us. But, ys, I think that the real mission of Opertiv is to offer a safe and validated way for committed, specialized knee surgeons to introduce new innovations for their patients, in a safe and responsible way that puts the patient first – that's our mission.

Dr. Randale Sechrest: Well, and I would probably say that there is nothing wrong with pursuing excellence. I think that if you're creating a training program to allow surgeons, whether we call the elite surgeons or not, to pursue excellence in terms of providing this level of service, then kudos to you.

Dr. Craig McAllister: Well, we have had a lot of fun doing it. You know as well as I do, when you have the opportunity to teach, you get better. And I learned more from teaching surgeons and interacting with surgeons in a cadaver setting with real concerns and legit opinions and ideas. To me, that's a brain trust around the table. I have actually learned more from all of those experiences than I have any formal teaching situations since I left fellowship.

Dr. Randale Sechrest: Well I think that's probably a good observation. I think as we close this discussion, which has been a fabulous discussion about the philosophy of I think minimally invasive techniques and where this is going, do you have any observations about where you would like to take Opertive into the future – over the next several years? Where do you see this all going?

Dr. Craig McAllister: Well, as you know, I believe in always striving to get better at things, and I really do believe that computer navigation enables the surgeon to dial up his or her standards one level higher. It's a technique and a technology that needs a company like Opertiv to promote it. So, we are highly interested in making sure that computer navigation is successful and granting access to that technology to patients and their doctors. So certainly that's the short-term goal is to spread the word about computer navigation and the opportunities that it offers for minimally invasive knee replacement.

Dr. Randale Sechrest: Well, I definitely wish you all the best in that, and if there is anything that we can do to help you get that message across, we'll be glad to do it. Any last minute comments before we close this discussion today?

Dr. Craig McAllister: No, Not really. Just thank you for the opportunity to talk to you today and if anybody, surgeons or patients have any desire to pursue this further, obviously they can go to www,opertive.com There is a lot more detail and actual live surgery videos if they want to see those. And surgeons are obviously welcome to come to our lab at any point.

Dr. Randale Sechrest: Well, thanks for that, and we'll be talking with you in the future I'm sure.

Dr. Craig McAllister: Thanks a lot Randale.