iKnee Method of Artificial Knee Replacement

Dr. Randale Sechrest: Hello. I'm Dr. Randale Sechrest your host for eOrthopodTv. Today, we'll be talking again, remotely, with Dr. Craig McAllister. Dr. McAllister is an orthopaedic surgeon who practices in the Seattle area. Dr. McAllister did his medical school training at the University of Washington. He then went on to complete an orthopaedic residency at the Albert Einstein College of Medicine. And from there a reconstructive fellowship in hip and knee surgery at the Cleveland Clinic. Today, in addition to practicing orthopaedic surgery, Dr. McAllister is also the President of Opertiv, a company in Kirkland, Washington that trains surgeons on the “iKnee” method of knee reconstruction. Operativ also creates surgical instruments and implants to help knee reconstruction surgeons do their job. So, thanks for joining us today Dr. McAllister.

Dr. Craig McAllister: Well, good morning Randale. Thank you for having me.

Dr. Randale Sechrest: Dr. McAllister today I thought we could discuss your new”iKnee”method of knee reconstruction that you've been working on for several years. I understand that you have recently brought your techniques into the marketplace with your new company, Operativ. Can you give us an ideas of what this concept of “iKnee” surgery or the “iKnee” method is?

Dr. Craig McAllister: Well, ya, I'd like to. First of all understand that knee replacement has been around for a long time. It certainly one of the most popular operations out there. In the United States we'll do 600,000 of them in 2010 alone. And knee replacement as it stands as a traditional method has a long and very well established track record. A track record that is supported by surgeons that have been trained in their residencies, know how to do the technique and are very comfortable with it. As an operation it's been incredibly successful. However, as we all know, knee replacement also has a well-established history for being a big operation, one that requires a reasonable amount of rehab, and one whose instruments have evolved considerably over the decades, but have never really integrated some of the more significant technological and computer enhancements for the operation. So there are two things that the iKnee method brings together, really for the first time in one integrated effort – and that is to combine minimally invasive surgical techniques with computer navigation. And, it is that combination of MIS surgical techniques with computer navigation that really constitutes the iKnee method.

Dr. Randale Sechrest: And can you explain for patients what the advantages of computer navigation are when you're trying to perform a total knee replacement?

Dr. Craig McAllister: Well, first of all some of the combinations, some of the advantages of computer navigation are really meaningful whether or not the surgeon is doing minimally invasive surgical techniques. And then there's another group of advantages of computer navigation that specifically address the demands of minimally invasive surgical techniques. So first, lets just talk about the basic advantages of computer navigation.

The first one is, and probably the most remarkable, is that for the first time the surgeon, and everyone else in the operating room, is getting real-time feedback on every step of the surgery. Let me just divert for a minute and explain the way navigation works. Light emitting diodes are attached to the the leg and they communicate with a camera in the room. The surgeon then takes a digital probe and paints the rest of the knee. So, from that moment on, the surgeon has a real-time digital representation of the leg in every step that we make from bone cuts to placement of trials, and alignment of the leg. So what happens is the surgeon gets real-time feedback on every step in the alignment of the leg and they end up with a much more reliable set of component positions and overall limb alignment. Statistically we get from about 70% accurate to 98% accurate when we use computer navigation. So accuracy of implants, accuracy of alignment – all that has to to do with whether or not the surgeon is using minimally invasive surgical techniques. But, when it comes to minimally invasive surgical techniques we're on whole another plane of advantages. The computer, and the probe that we use to access the landmarks in the leg is really much smaller than traditional instruments, so the need for surgical exposure is considerably less. Also, as you know, Randale, traditional techniques in knee replacements are premised on placing a pretty sizable rod right up the femoral canal. And that may sound a technical and difficult to understand but the upshot of it is that that rod is not as precise as a navigation tool, but also it causes considerable blood loss and what we call fat embolist syndrome, so there is more morbidity associated with the placement of that rod. Navigation eliminates that. So, there's a sense of blood, preservation of blood loss, and avoidance of complications that also makes navigation more minimally invasive.

Dr. Randale Sechrest: I think the take-home message for patients is probably this. In the old days when we used to use these jigs you've described to align the knee and get the alignment right during the surgery, this required some fairly big incisions in order to be able place the jigs on the knee and the rod up the femoral canal that you were talking about. And I think any surgeon will tell you that there was a heck of a lot of fiddle factor and a lot of guess work even with the jigs. I think you brought up the point that there was a significant variation in how a surgeon could actually put in a knee replacement from patient to patient, and it wasn't always completely accurate. If I understand what you're saying, we're now using these computerized techniques that not only require less invasion of the knee, but they also really reduce that variability from patient to patient. The knee is more consistently aligned and you and I would argue this makes for a better functioning knee that is going to last longer than the ones that aren't put in so accurately. Is that accurate?

Dr. Craig McAllister: Very well said. There are other advantages as well. Particularly when computer navigation is associated with or combined with our instruments. Because what the navigation does, really for the first time in the history of knee surgery it creates an independent platform where a couple of advantages are achieved. One, the surgeon can use virtually any kind of implant out there on the market that he wants to. In other words, it becomes an all-inclusive system. And, as you know, historically, the instruments that are used to put knee replacement in are proprietary and they're combined with the implant. That has all kinds of ramifications for the hospitals and for cost containment, because it means that these very expensive sets of instruments all have to be duplicated within a hospital, depending on how many different types of knee replacements are being put in by all the different surgeons. Whereas this platform of instruments with computer navigation universalizes that for all types of implants and it actually reduces the cost and the complexity of maintaining the instruments for the hospitals. At the very same time. These instruments are giving the surgeon considerably more freedom in how the surgery is done. For example, you know, without getting too technical, you remember that historically knee replacements were either a posterior referencing, or anterior referencing, and that gets too be somewhat complicated, but with navigation it can be either one. So, the surgeon's choice for that particular issue can be made dependent on the patients knee. Maybe something that is more familiar to the audience would be gender sizing. We came to realize in around 2002 that, low and behold, a woman's knee is a little bit different from a man's knee. Yet, the implants have to be really designed – we can't carry female knees and male knees – like we do in the shoe department. We carry one set of knee replacements. What navigation lets the surgeon do is size, depending on which feature, male or female he wants to size the knee on. That's not in the systems that are not navigated.

Dr. Randale Sechrest: So what we're describing is a way that their surgeon can ultimately do a better job of replacing their knee. What does that mean for patients? How is that going to translate into what the patient experiences?

Dr. Craig McAllister: Well, that's a very good question. And that question goes to the heart of why is it that really only about 3-5% of knees in the United States are navigated today. Interestingly enough, a knee can be out of alignment pretty significantly and the patients won't notice it. What we have found is that patients will be able to perceive a knee that's about five to seven degrees out of alignment. Eight, nine, ten degrees gets to be really noticeable. They won't really perceive a knee that's five degrees out of whack, but at least not in the short term. In the long term, 10-15 years, in terms of the longevity of the knee replacement. We all believe that that having our aligned within three degrees is a lot move advantageous in the long term than it is to be within 5-7 degrees. The same holds for component positioning. The truth is, with traditional knee replacements, especially with big incisions, I think one of the things that helps orthopedic surgeons is that it's a very tolerant surgery in the short term. We can have our components a little out of whack and the patient will be better off than they were before surgery. Their knee might feel a little clunky or maybe it won't be quite as stable under stressed situations. But Randale, as you know, this is the era when our knee replacement are being done in higher and higher demand patients. Patients that want to bend down deep, check their put, maybe get in and out of a sand trap, get in and out of a car, garden, they are a more active set of patients. So, in the short term, if the computer enables us to get our component position more and more accurately, we will see fewer problems with instability and stiffness in that short-term, one or two year followup.

Dr. Randale Sechrest: And what about long-term? You alluded to the fact that if we get these knees more accurately placed, that they're more likely to last the rest of the life of the patient – or at least longer than knee replacements do now. What's been your finding in terms of using computer navigation and what do you predict is going to happen in terms of the longevity of these knees.

Dr. Craig McAllister: I'm glad you phrased the question the way you did, because you differentiated what we've found in our outcomes, versus what we predict. Computer navigation as we're teaching it really has only been around since 2003-2004. We've done thousands and thousands of knees using this methodology and we have considerable data in terms of long-leg alignment films and short term follow-up with our patients, and what we have found is that our alignment and we, like every large center in the United States, and every experienced surgeon out there who has looked at their use of traditional measures, we were hitting about 70% of our knees in that alignment range that we wanted. Which is pretty humbling, really. With navigation we were able to increase that accuracy to 98%. Not only in terms of alignment, but component position. We were able to see our blood loss for our patients drop from 32% to 2% and virtually eliminate transfusions. Our length of stay in the hospital has gone down, our incision size has gone down. We published a series that looked at pain, range of motion, stability, and return to function, all in that short term, two year time period, and we have documented that minimally invasive techniques combined with computer navigation improve all those parameters. In terms of 10-15 and 25-year follow-up, obviously we can make predictions and extrapolations, but until we're in to 2015, 2020, 2025, we're not really going to be able to prove that these navigated knees are going to last longer than non-navigated knees. I think, however, that most of us as orthopedic surgeons will argue that intuitively a well aligned knee has a much chance of avoiding failures due to polyethylene wear, and other things that are alignment sensitive.

Dr. Randale Sechrest: You know I think that most patients that are listening to this at this point are probably asking themselves “well, why wouldn't I want a knee that has been placed with these new techniques” - the computer navigation and some of the instruments that you're referring to. So, I guess, are their any down sides to this, or is there anything that you see that perhaps computer navigation doesn't do as well as the old fashioned way?

Dr. Craig McAllister: Well, I think that yes, there are some significant hurdles and disadvantages that help explain why navigation is only present in 3-5% of the market out there. In terms of is there anything that traditional measures can do better then navigated measures – I'd say well, only because it's already taught and it's easier. But there really isn't anything that traditional measures let surgeons do that navigation can't do. In fact, it's quite the opposite. Navigation does everything better than traditional measures. The problem is, computer navigation is expensive. It's a $250,000 set of hardware that the hospitals have to invest in. And it's also expensive in terms of a learning curve, and resource allocation. You can appreciate that for an orthopedic surgeon to deviate from traditional measures to computer navigation navigates measures would a) require considerable learning curve and b) a significant commitment to knee replacement surgery. There are some practical issues with that. As you know, the majority of knee replacements done out there in the United States today are done by surgeons who do fewer than 20 or 30 a year. So, to commit that much of the surgeon's time, and his staff to learning these new techniques can be a significant hurdle. And that's one point where I wanted to discuss the role of Operativ. We recognized this early in 2002-2003 and we really exploited our lab to be able to overcome a learning curve in our cadaver lab and not have to endure that learning curve in our patients. We developed the instruments so that we and the other surgeons could integrate these techniques in an incremental, safe fashion, instead of an all-or-nothing fashion. So we think that by using our lab to teach surgeons and we have trained over 250 surgeons in these techniques and have five or six centers out there where they are navigating all of their knees. Combining our learning center and our learning methodology with instruments that enable to surgeons to either navigate or not navigate, use traditional measures or MIS and navigation measures at any time during the operation helps to eliminate some of those barriers. Lastly, the cost of computer navigation is coming down annually.

Dr. Randale Sechrest: Well, I guess that brings up the question is what do you see for the next five years in computer navigation and some of the techniques that you're championing now through the iKnee method? What do you think is going to have to happen in the market place for that to change so that any patient could actually access a surgeon that has this level of training and is using these new innovative techniques?

Dr. Craig McAllister: A few things. 1) the cost of computing, the cost of navigation needs to come down. 2) We have to create earlier, and or rather easier sequences for the surgeons to learn the techniques and integrate them into their practice. Both of those fronts we're making good progress. Finally, I think the last thing is that the patients out there need to become educated on this technique, these techniques, and understand the potential advantages for them and simply begin to demand them. The truth is navigation doesn't really bring a profit margin to the implant companies, and it only helps save costs in the long term. So, without patient demand for navigation, realistically, I think it won't progress as fast as we would like it to see. So patients need to understand it.

Dr. Randale Sechrest: Now a questions I think about computer navigation in general. You know, a lot of the things that we use, for example, fluoroscopic x-ray machines. We use those for a whole set of different types of procedures, so, purchasing a $250 - $350,000 piece of equipment is pretty cost effective when you can use that piece of equipment for multiple different things. Is that true of computer navigation? Is this only used in these reconstructive procedures that involve artificial joints? Are we beginning to use this technique and this equipment in a broader array of procedures that might make it more cost effective to have this equipment in the operating room literally for any operation that we do?

Dr. Craig McAllister: You know the whole era of integrating computer technology into the operating room is well under way. We hear about the Da Vinci system and the utilization of computer and robotic techniques and surgeries from prostate surgery to hysterectomies. We have other computer technology coming into the partial knee replacement market. But you know as well as I do that the medical market place is a very complicated, very convoluted place. Some of these technologies are, the costs are retrievable to the hospital and some of them are not. As long as traditional measures will be accepted by surgeons, and navigation techniques discounted by the overall marketplace, and as long as patients are not aware of it and don't demand it, there is really is no strong financial incentive at this point for hospitals to make this rather significant commitment. However, the patients are becoming increasingly well educated and that demand is increasing, so I think we're going to see dramatic changes in the next five years.

Dr. Randale Sechrest: Well lets give patients some recommendations in terms of how to navigate this terrain. If they decide that they need a knee replacement and they're interested in seeking out a surgeon that is trained in these techniques, how would they go about doing that today?

Dr. Craig McAllister: Well, I think this is one of those same answers I will give to all these questions about how patients should navigate the medical system. First and foremost, primary care doctor and their own personal orthopedic surgeon. But when you get to the orthopedic surgeon, go there with a set of questions in hand about this technology. Go to the Internet, use the Internet to help craft your questions. Find out if navigation is available in your community. If it is, who's the surgeon that really is doing a significant numbers of navigation techniques? If navigation is not available in the patient's community, use your orthopedic surgeon to travel outside of the zip code and find a surgeon that is doing it. If after talking with your primary orthopedic surgeon and your second opinion consult, you feel that navigation is for you, you might need to be able to travel outside of your community to have that technology.

Dr. Randale Sechrest: In closing in this discussion about the iKnee method and computer navigation, I'm going to put you on the spot and ask you to predict, in your own opinion, where we're going to be in five years, and ten years? Are we going to see this change dramatically over the next five years? Will we see computer navigation as the standard within the next decade in your opinion?

Dr. Craig McAllister: I think for the next 5-10 years, what we're going to see is some patients getting these techniques. They will be the patients that take the time to find out about the technology, to seek out the doctors who have it, and the certain hospitals who have it, and are willing to put that extra effort in to find it. They will be the higher demand patients, the younger patients, the patient who might actually have to help pay for some of that technology themselves. After ten years, as the technology becomes more and more commonplace, as the costs comes down, and as residency programs actually start teaching these technologies, it will become the standard of the industry. And it will just be easier and simpler and cheaper for everybody to get it with computer navigation.

Dr. Randale Sechrest: Well, this has been an excellent, eye-opening discussion about the place of computer navigation and knee replacements. As you close this discussion, is their anything that you think patients would benefit from knowing, that we haven't discussed up to this point?

Dr. Craig McAllister: No, I would just reiterate that the importance in this era when it comes to elective surgery, like knee replacement, go to your orthopedic surgeon with a good set of questions in hand, and be willing to help allow that orthopedic surgeon to help you get a second opinion before you make these decisions.

Dr. Randale Sechrest: Well, I want to thank you for joining us today, and look forward to more information as the iKee method becomes a little bit more known in the marketplace. So thank you very much.

Dr. Craig McAllister: Thank you Randale.