Yair Kissin, MD, Vice Chairman of the Department of Orthopedics at Hackensack University Medical Center, talks about a new system for customizing knee replacements and improving their longevity.
What’s the traditional way when there’s an injury or some problem with the knee you need to fix?
Dr. Kissin: In our practice, I was lucky enough to train with some of the top knee surgeons in the world and stayed with them in practice, one of them being my chairman Dr. Michael Kelly, a famous knee surgeon known worldwide for his contributions in knee surgery of all kinds. We evaluate patients from young people to elderly people who have injuries that just require some physical therapy. Those with non-surgical means, which is the mainstay of a lot of treatment protocols for us, from little meniscus tear surgery, ACL surgery, all the way up to knee replacement and redoing knee replacements when they sometimes fail. So, when we evaluate patients, we really have to decide what’s best for them. It’s not a one-size-fits-all type of practice. We’re able to treat a knee regardless of age and regardless of condition, based on what that patient needs.
Is this new system for replacement only or is it for a variety of different kinds of needs?
Dr. Kissin: Replacement only. Traditional knee replacement involves us cutting out the area of the arthritic joint. In the case of the knee, it would be the end of the femur and the top part of the tibia and oftentimes the back of the kneecap as well. The mainstay of knee replacement is we have to bring the patient’s alignment back to normal, put the position of the patient’s implanted joints into the right position for the knee to work mechanically correctly. Then rehab them well so that they can get back to the activities they hadn’t been able to do because of their knee pain.
How’s it done traditionally?
Dr. Kissin: So normally we would use a variety of cutting jigs and guides that help us determine where the correct placement for a knee actually is. It’s been one of the most successful, if not the most successful, surgeries around. It has survivorships in the upper 90% range for 10 and 15 years and also in the 90% range for greater than that. We’re not, at this point, worried about how long these are going to last. We know that about 20% of patients are unsatisfied with their knee replacement and dissatisfaction certainly comes in different ranges. Dissatisfied that they can’t do everything, people usually accommodate their lives and deal with that, but sometimes people are so dissatisfied they need a revision knee replacement. We’re trying to peg how to avoid those 20% in the future and maybe make that number a lot less. Part of the issue, we think, is that maybe we’re not hitting the bulls-eye as accurately as we would like to. The cutting jigs and the tools that we traditionally have, are to make operation simpler, but at the same time, it’s not necessarily personal to that person’s anatomy because everybody’s knee is different. Even the left knee and right knee are different in the same person and there are good studies to that effect. So, now we move on to perhaps the next level of how we do things. robotic surgery has been introduced in various platforms. There are platforms that still allow the surgeon to use a traditional saw and cut through a guide, kind of similar to what we used in the past, but that guide is aided with a mechanical arm. Then there are other systems where the surgeon’s hand is on the cutting tool, but that cutting tool’s attached directly to a robotic arm with some haptic feedback. For this particular system called, Think T Solution One, I was very privileged to be part of a study team for the FDA approval, which we just got in October. There are five centers in the country in Cleveland, Manhattan, Houston, Hackensack, and North Carolina – where we studied 115 patients. We did 25 here at the medical center. And enrolled patients in a new way of doing things. It really changes the way I have to think about surgery. There was a pre-planning that I had to learn that we never did before. There were CAT scans done so that we can get that patient’s exact anatomy, plan surgery virtually in our office and then execute it in the operating room using a mechanical arm.
If you could walk me through the differences, how would you do surgery now with the Think T Solution One?
Dr. Kissin: With the Think robot specifically, its what’s called an active robot. Active robotics means that the surgeon has to give up control of the cutting device- which is not so easy for a surgeon to do. But essentially, we have a little control lever with an on-off button and the device is cutting before our very eyes, what we would normally do with a saw and directly with our hand on the cutting device. So, they changed the paradigm a little bit and it was certainly a bit of a leap of faith in the first case or two. But once you saw what it was doing and how well it was doing it, you really believed in the technology. What happens is a burr comes in after you’ve registered the knee in space, that registration gets compared to the pre-operative plan and the CAT scan that was done, and then a very fine-tipped burr cuts the bone to the specifics of that plan.
You say it’s registered. Is this done in real-time?
Dr. Kissin: It’s done in the operating room. Registration is done with a little stylus where the machine decides if it matches correctly and appropriately with the preoperative plan. So, you have two levels of pre-op planning and then also intra-operative verification of that plan.
So you had mentioned a pre-op plan that scans to determine exactly how the person’s knee looks and that matches up the day of surgery?
Dr. Kissin: Right. You’ve done the plan in your office. You’ve decided on the placement of the implant, the size of the implant, the orientation of it. Then you get to the operating room and you need to verify that the person’s anatomy is actually what you thought. So, the two are melded together in the robot before it delivers the execution of that plan.
Is there a point where the surgeon jumps in? And can you stop if you don’t trust what you’re seeing from the robot?
Dr. Kissin: There are systems where the surgeon is in full control. So, if they don’t like where the robot is placing it, they can abort at that point. With this particular device, there is a start-stop switch and luckily there were none of our cases where while it was cutting, we had to abort the mission and go to a manual mean. We were always ready to do that just in case, but in our 25 cases, we didn’t have to do anything like that. It came out the way we expected it to come out.
How much time is it doing the surgery? Is it faster?
Dr. Kissin: As these systems are in their infancy and human nature is such that we want the final product already, it’s hard to want everything to be appreciated all at once. So right now, it does take a little bit longer. Once the learning curve was over for us in the study group – and keeping in mind that in a study, we’re extra careful not to rush through things and we’re still early in the study at the time, it took about 25 or 30 minutes longer than a traditional knee. Ultimately, we would hope that once things get going, and also a few changes to the way things are done by learning how to do it a little bit better, time neutrality is probably something that we’ll end up seeing but too early to say that.
What’s the benefit for the patients?
Dr. Kissin: The study was involving evaluating this device on 115 patients to see if it was safe, which we proved that it was accurate and effective. Our accuracy data hasn’t been published just yet. We’re working on compiling it so that it can really show what we’ve done in the study. We showed that it was quite accurate, accuracy meaning that we tested those patients who were in the study with a CAT scan three months later to see if that plan that we executed was actually the plan that we wanted and the accuracy data was actually very impressive. So, we hope that by making some of the pre-operative planning accurate, the intra-operative execution by a machine rather than by the human hand, which is kind of hard to argue that machine can’t make a bony cut better than a human can, we can improve. We just have to figure out what the right machine is to do that. But if you look at your furniture it’s done mechanically by a machine and it has very fine angles and everything fits together, conjoined very nicely as it’s supposed to be. In traditional surgery, we use a saw and obviously the human hand and so there are inherent inaccuracies in doing it that way. We hope that if we can maybe take some of those out, then maybe we’ll have better outcomes. Time will hopefully prove that with more studies.
What about recovery time. I know one of the things we’ve from heard doing stories on parts replacements from people is that the knee takes a lot of rehab and a lot of time just getting back on your feet. Is it anticipated that this might ease that recovery time?
Dr. Kissin: I think that’s what we all hope to see. I think it’s too early to be able to claim that. But I do believe in the study patients that I’ve seen if you get the knee accurate to that patient’s personal anatomy, not to the anatomy that our standard cutting jigs, it would put them in a little bit more correct to that patient’s actual anatomy. We hope that that means that the patient will be able to have a more functional knee faster – can’t say that just yet as that’s not what the study was out to prove.
Tell me a little bit about the patient. We have consent to use names.
Dr. Kissin: Yes. Right. So, my patient Ms. Santos, one of our loveliest patients regardless of the study, had a traditional knee replacement done with me originally and needed her second knee done just as we were enrolling patients in this study. She was happy to, she was doing very well with the first knee and was very happy to enroll in the study. She’s a very enthusiastic patient of mine. She lives her life to the fullest despite, unfortunately, some tragedies in her life. She was always very motivated very honest. If something hurt, she would tell me. Before she had her first knee done and then until she had her second knee done, her life was very limited. She is a very spunky, very energetic patient of mine. She was actually our most senior patient in the group, she was happy and proud of that fact. But she did very, very well, thankfully.
Is there anything she said she’s back to now, that she was not able to do before because of the knee pain?
Dr. Kissin: I’ll let her tell you, but her life was very limited when it was both her knees. She’s not heavy, she’s as healthy as they come at her age, she was just physically limited in her mobility.
Is there anything that I didn’t ask you, Doctor, that you want people to know about this system?
Dr. Kissin: I think that it’s exciting technology. I think that it’s wrong to make claims about things like you asked about earlier, recovery and outcomes and things like that. It’s what we hope to see down the line. For the short-term, what I see the big benefit of this kind of technology and specifically with the Think robot, is that we’re actually able to personalize the surgery. Standardize the surgery to that patient’s knee, not to a plan that fits most patients with the typical traditional way of doing a knee replacement. The exciting part for me was that it actually had to change the way I look at how I do a knee replacement. I had to plan the surgery before- the surgery was done before we even started if I made a good plan. If I made a bad plan, the robot would execute a bad plan. But luckily, we were able to show that our success rates were actually quite good and our data, we’re very proud of our data, and we hope to share that very soon.
So that data hasn’t been published yet?
Dr. Kissin: In the works. And as we go forward, I think that one of the most important things we will, as a group of surgeons, determine what technology is the right technology. I think it’s going to be data-driven. If you look at your outcomes in a way that is very critical and very honest, then I think that’s going to be the best way to decide what machines we need for and what help in doing something we, and our predecessors and teachers, have already been doing very successfully. We’re not trying to change the overall principles, we still want what’s best for our patients, but there may be a tool that may help us do it better and standardize things. In a world where the number of total knee placements is expected to rise exponentially, we have to figure out a way to make things more efficient, make things more standardized and last longer so that we don’t have to redo too many knees. If we can get it right the first time, then perhaps they’ll last longer, and we’ll have less of a burden of re-doing these.
Interview conducted by Ivanhoe Broadcast News.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
If you would like more information, please contact:
Mary McGeever, Public Relations
Hackensack University Medical Center
Mary.McGeever@hackensackmeridian.org
Sign up for a free weekly e-mail on Medical Breakthroughs called First to Know by clicking here
