Scott Webb (Host): Though it's not the gold standard yet, muscle or quad-sparing knee replacements hold a lot of promise for patients who are reluctant to have knee replacement surgery or simply need to get back on their feet faster. And joining me today to tell us about the many benefits of muscle or quad-sparing knee replacements is Dr. Ismar Dizdarevic.

He's an orthopedic surgeon out of Ridgewood, New Jersey, where he maintains a private practice performing hip and knee replacement surgeries at Valley Health System. He also chairs the Total Joint Replacement Program at the Valley Hospital in Paramus, New Jersey.

 Welcome to Conversations Like No Other, presented by Valley Health System in Ridgewood, New Jersey. Our podcast goes beyond broad everyday health topics to discuss very real and very specific subjects impacting men, women, and children. We think you'll enjoy our fresh take. I'm Scott Webb.

Doctor, it's nice to have you here today. I was just mentioning to you that my mom had a knee replacement and we never talked about muscle-sparing knee replacement when she had hers done. So, great to have you here. Great to learn about this today. Let's start there. What is muscle-sparing knee replacement?

Dr. Ismar Dizdarevic: Most people when they hear knee replacement, they just assume it's kind of a one shape, you know, fits all. And true muscle-sparing or quad-sparing knee replacement or subvastus knee replacement, as most people will term them, is a special surgical technique that really avoids cutting the quadriceps muscle or the tendon, which allows for the critical structures of the knee to be fully preserved during the surgery.

It is the most minimally invasive way of doing a knee replacement. And when you compare that to a traditional knee replacement, that always involves cutting either the tendon or a portion or majority of the muscle itself of the quadriceps. By cutting these muscles and tendons, the recovery really becomes longer, it's more painful. It's, in a lot of ways, more unpredictable and some patients never are able to regain the strength of that muscle to its, absolute capacity, which can lead to abnormalities of gait, stiffness, pain, and just overall suboptimal knee function.

Host: Sure. Yeah, you mentioned minimally invasive there, and I know that's kind of one of the buzz things, buzz terms in medicine, we all want minimally invasive, even if we don't entirely know what that means. So like, what's the biggest misconception, I guess, when patients hear that minimally invasive or muscle-sparing? What do they picture in their heads?

Dr. Ismar Dizdarevic: A lot of times when you hear minimally invasive people assume that what you're talking about is something that does not require making any sort of trauma or injury to the area that we're operating on in the setting of laparoscopic surgeries. They're oftentimes seen as these very, very small kind of punctate incisions, and there's lots of surgeries that can be performed from an all-inside technique. This is still a knee replacement. You still have to be able to get in a piece of metal that has a certain geometry into the knee itself. But what I tell people the biggest misconception is that just, in general, all knee replacements are the same. You know, a knee replacement surgery is like a fingerprint. Everybody has their preferences on how they balance the knee, what kind of approach we use, the implant positioning and the implant choices, and all of these decisions make a critical aspect to a patient's recovery and, ultimately, their satisfaction.

Host: Right. Yeah. I was going to ask you, you know, well, why haven't we always just been doing it this way? Why haven't we always been sparing the muscles? But I'm guessing it's not right for everybody. As you say, it's not one-size-fits-all. Maybe not everyone's a good candidate for it. So, that leads me to my next question, like, who's eligible for this type of surgery and maybe who isn't?

Dr. Ismar Dizdarevic: So, it is possible to perform the surgery on just about every patient. You know, barring any major deformities or major anatomic changes to the knee, somebody who has hardware or osteotomies, which is procedures that may be required, the cutting of bone, prior arthrotomy. But patients that have a very active lifestyle and who need to rehab as soon as possible is the ideal candidate. You know, think of people that can't take three and a half months or three months off to rehab the knee. These are the caregivers, moms, dads, teachers, you know, self business owners, where time is of some crucial essence, and there really seems to be a benefit in that first six weeks. But it can taper off, you know, after that. So if somebody is older or retired or deconditioned, I think that, you know. They may not see the benefit in those first six weeks regardless, and they may be exposing themselves to additional, risk.

Host: Yeah, I know in the case of my mom when she had her knee replacement, it was a long road. Lots of PT, a painful process. She's fine now, of course, but she had this a little bit older in life, close to maybe around the age of 70 or so. I wanted to ask you more about the recovery. It sounds like the muscle-sparing procedure recovery is faster and easier. Can you give us a sense of why?

Dr. Ismar Dizdarevic: So in general, I always like to preface by saying that all patients, all people have inherent aversions to surgery, especially knee replacement surgeries, when you can talk to 10 different patients and hear 10 different stories. So, knowing ahead of time that there is less trauma being done with this approach, I think, in a lot of ways eases anxieties, which is a huge part of our recovery process. So intuitively, it makes sense.

If I ask you, would you like for me to cut your muscle or not cut your muscle? Most people wouldn't inherently respond, "Do you have to cut my muscle?" And it turns out you really don't have to with the appropriate training. So when we take this and we couple it to robotics and our now understanding of what we call personalized or functional knee kinematics, which is the kind of the movement of the need that we're all trying to achieve, we really see that limiting soft tissue damage does now help make the recovery easier. And this isn't just my feel or, you know, the sense that I'm getting from my patients. Studies have looked at this. And even years ago, we looked at tissue damage markers, knee range of motion, the strength of the muscle, what we call get up and go scores, which is how fast somebody can stand up from a seated position and get back to activity. And then, even short and midterm pain scores all seem to be pointing to a direct advantage of what we call muscle-sparing or subvastus-sparing techniques.

Host: Yeah. As you say, it's not just an anecdotal like your gut, right? This has been researched and studied, and you're doing this procedure or both procedures on patients over the years. It makes me wonder like how different are the procedures? Like a knee replacement, as you say, is a knee replacement, right? And minimally invasive is relative to the fact that you still have to replace the knee. But how different really are the two procedures?

Dr. Ismar Dizdarevic: What a patient will see when everything is done is that they have a smaller incision versus a traditional knee replacement. It may be something that may be three to four inches as opposed to six to eight inches, but what they feel is weeks of of a quick recovery and less pain. Like you said, a knee replacement still requires cutting of a bone that will lead to some, you know, instability to the need that we then have to rectify if we're able to make minimal bone cuts and remain minimal in our dissection to provide a stable outcome, we can ultimately provide a much more reproducible outcome.

So, because the majority of the knee replacement surgery is really just figuring out how do we see what we have to see and how do we expose the knee joint to allow us to put the implants in place, this whole quest for how small can we make our window, but at the same time maintain the safety of the surgery. That's been the big battle over the last 20 years. And I always kind of like to say that the reason that it's now starting to come to the forefront, is because we have now the ability to utilize robotics and avoid using cement, and some of these big problems that we encountered are now becoming fixable problems.

Host: Yeah. Yeah. Anytime we can talk robots, you have my attention, right? So robots, minimally invasive, smaller scars, faster recovery, all good stuff for patients, providers too, of course. Are there any downsides or complications maybe that they don't put in the brochures that you could tell us about?

Dr. Ismar Dizdarevic: Naturally, of course. You know, this is a very technical surgery and that it requires a lot of savviness and finesse and training. And because when I was going through my training, nobody was really feeling competent to do this because, again, the robotics was not at the forefront at that time. Very few surgeons across the country really chose to perform this, which ultimately means that less surgeons were training residency trainees and fellowship trainees on how to do it. So, outside of that kind of small little apprenticeship, you know, type of model, it really seemed that the industry, some of the companies that sell these implants were the ones that were really leading the charge on how we educate other surgeons on how to do this safely. And that's kind of where we are right now, is that I would love to see it more in our training programs, but there has to be a critical mass of surgeons that have adopted it before we can really start teaching through those means. Right now we seem to be kind of focusing on teaching surgeons that are years out and trying to hopefully help them, you know, recreate their practices.

Host: Right. I think the thing about this that I'm hearing is just it's less painful, right? And we all want that. Like you said, if you were to ask us, "Do you want me to cut your muscle or do you not?" "Well, no then. Please don't," right? Is that why it's less painful? Simply it's because you're just not cutting as much stuff. You're not cutting the muscle.

Dr. Ismar Dizdarevic: I think that's a big part of it, Scott. But pain as a general concept is a very difficult concept to try to make objective. You know, having acute pain and having chronic pain are two very different measures of pain.

Host: I see.

Dr. Ismar Dizdarevic: If someone was asked, "Are you willing to have more pain, but for a shorter duration? Or would you like to have less pain but have it be drawn out over months?" Some people may choose one path, while others may choose the other. But I do believe that muscle-sparing, you know, techniques lead to less acute pain and ultimately less long-term pain because it allows for that small window of time where rehab is critical to be maximized.

And more appropriately, we really, I think, should be measuring and describing the perception of a patient's rehab as opposed to just a very dichotomous, do you have pain, do you not have pain? And I think rehab as a real outcome measure is way more objective, and it's way more telling of the success because it's measurable. There are strength gauges, there's range of motion, there's swelling, there's return to reciprocal stair climbing, there is the forgotten knee scores. And I think, you know, focusing on that patient's rehab over that first six weeks, I think, is going to be a very telling story when it comes to knee replacements and what can we do with less invasive techniques.

Host: Right. Yeah. As you say, it's objective criteria. It's objective tasks and things during that rehab, not anecdotal or subjective or just someone's opinion about things. It's all really sort of quantifiable, which is good and hopefully leads to more surgeons wanting to do this and get the training and all of that. What's something you wish we all knew about this surgery before we sign up?

Dr. Ismar Dizdarevic: I think a decision to pursue surgery is a very, very big one for most people, and surgery should be the last step that helps you regain your function once conservative methods really no longer works.

And surgery works only because, by the time that these conservative treatment options have failed, it tells you that the knee damage is severe enough to be fixable with surgery. So surgery, I always tell patients, makes big problems smaller, but it doesn't necessarily make small problems zero. And your doctor can really help you determine if you're a candidate for this surgery.

Host: Right. Yeah. Put your faith in your providers. Go through this. As you say, it's not one-size-fits-all. It's very personalized or as much as possible anyway. Good stuff today. Learned a lot. I'm sure listeners did as well. I just want to get a sense from you long-term outcomes, you know, muscle-sparing knee replacement versus traditional knee replacements. What are you seeing with patients?

Dr. Ismar Dizdarevic: So, the truth is that the benefits really seem to be front loaded in those first few, let's say, six weeks. But I've always felt that when patients are doing well out of the gates, they tend to always do well. And while there's still ongoing research to really try to quantify these long-term outcomes and the effectiveness of less invasive surgery, but especially, you know, quad-sparing or muscle-sparing knee replacements.

Traditional methods still work. And most surgeons that have been trained in their, again, fingerprint of how they do a knee replacement will still do a great job for the vast majority of patients. What we're really talking about is trying to find a subset of patients that have less time and that have less desire to do a knee replacement in the first place and try to, you know, open up this world where we know we can help improve their function.

Host: Yeah, that's perfect. Well, I appreciate your time, your expertise today. Thank you so much.

Dr. Ismar Dizdarevic: Scott, thanks for having me.

Host: And for more information on joint replacement at Valley, please visit valleyhealth.com/jointreplacement. And if you found this podcast helpful, please share on your socials and check out our entire podcast library for topics of interest to you. And thanks for listening to Conversations Like No Other presented by Valley Health System in Ridgewood, New Jersey. For more information on today's topic or to be connected with today's guest, please call 201-445-2830 or email valleypodcast@valleyhealth.com. I'm Scott Webb. Stay well.