Transcription:
Knee Revisions and the Latest Technologies in Replacements and Revisions

Bill Klaproth (Host): Knee replacement surgery can help solve stiffness or knee pain that makes simple activities difficult. Surgery may also be the best option if other treatments or medications haven’t been successful. And here to talk with us about orthopedic knee revisions is Dr. Karl Balch and orthopedic surgeon at Dignity Health. Dr. Balch, thanks for you time. So, for someone who has had a previous knee replacement surgery, what are the main causes of knee problems?

Karl Balch, MD (Guest): Sure, so when you have a knee replacement, there are different kind of classes of things that can go wrong or problems that can happen to it. there are things where they can have problems kind of from the get go, meaning the alignment on the knee replacement when it was placed in was not quite correct, then that can make it function poorly after surgery. Or there are other things like the angles and positions that things are put in, that can create different problems. There are things where the knee replacement can be unstable or make the knee less stable, so it can give out on you or you can fall down and part of that can be based on the way it’s put in or the parts and kind of as the way they are in as well. So, those are all kind of very early ways that knee replacements can have problems.

There’s kind of middle kind of range of where things can have problems meaning that they are a little further out where someone has an injury, a fall or some kind of accident where they can either damage the knee replacement or the parts, so they could start to collapse, things like that. And then there’s the long-term ways that knee replacements fail and that’s more about the plastic liner in between the knee replacement can wear out over time. I make the analogy with my patients to tread on a tire, you know over time, your tires kind of wear out the longer you use them and most knee replacements; the average knee replacement lasts about 15 to 20 years before that plastic kind of wears all the way out. And once that happens, the knee replacement can start to get looser, be more unstable and have problems.

Bill: So, what are the common symptoms then that somebody would experience when the knee is going bad if you will?

Dr. Balch: Yeah sure, so, knee replacements if they are having more pain. You know a knee replacement is really done as a pain-relieving procedure so, if you are having a lot of pain with it ever since it was done; that may be something abnormal or something wrong. If it is something where your pain has been getting worse, that’s always a big red flag to me. A knee replacement should either stay the same or get better, it should never be hurting more. That’s a red flag that something may be kind of awry. Or if it is giving out, unstable on you. People have falls with these sometimes. That can also be a sign that maybe something with the knee replacement is not correct. Those can all be problems that can be based on the way the components are aligned, the way things are positioned; all of that can be really important on if it hurts, it it’s stable, if it’s giving out or causing problems.

Bill: So, at what point would you need to go in for more surgery or again, replace what is already been replaced? When is surgery needed?

Dr. Balch: Yeah, so whenever I see a patient who has had a knee replacement done elsewhere and they are coming to see me for an opinion about what’s going on, we always check to see kind of the not quite emergency, but the more urgent things that can be wrong. So, we always check for infection or damage to the metal or other components and things like that. Now if there is a fracture or an infection or something like that; obviously, that’s something you kind of can’t let that go. You kind of got to fix that. So, I always look for the got to fix it stuff first. And if there is no got to fix it stuff that’s damaged or messed up; then we look for the other things that are things that can kind of reduce the function or kind of make it not quite work as well and those are things that can be fixed with surgery; but first you can also try therapy, braces, I mean a lot of other non-surgical things first. So, if I identify problems and it is nothing catastrophic; first we will try the nonsurgical stuff first and if that’s not working, and it’s reducing your quality of life, the activities of daily living that you do are harder and harder so, the basic stuff you need to do day-to-day is tough; then that is where we will start considering undergoing a revision knee surgery. So, it’s really about pain, function, what else have you tried and then also what exactly the problem is. More severe problems are not going to do as well without surgery to fix it. More kind of manageable problems, some of those require surgery and then some of them don’t.

Bill: I like that, the got to fix it stuff first. So, Dr. Balch, let me ask you this, what about partial versus total knee replacement. What are the unique benefits of each?

Dr. Balch: Yeah, that’s a great question. So, I really, really enjoy partial knee replacements. Now when you look at partial and total knee replacements, most people that you have probably met who had a knee replacement, the most common thing is for people to get a total knee replacement. And that’s because most orthopedic doctors will do a total knee replacement. Now there’s a more specialized procedure called a partial knee replacement. And what that does is that it only replaces a small section of the knee. So, it doesn’t replace all of the areas of the knee like a total does; it just replaces one particular area. Now when they look at the data on partial knee replacements and total knee replacements; a partial knee replacement is better than a total knee replacement in basically every single way you can think of except for two things. So, it has better range of motion, it recovers faster, there is less complications, less risk of blood clots, faster surgery, less time in the hospital, less blood loss, I mean on and on and on.

So, they are really, really wonderful but there are two things you got to keep in mind for a partial knee replacement. One is because it only replaces one section of the knee, you can still get arthritis in the other sections of the knee. So, you really got to be the right person. You have to have arthritis just in one section and when they looked at the knee replacements, a total knee replacement versus the partial knee replacement; and the looked at all the knee replacements in the entire country; a total knee replacement lasts longer on average. And that makes sense if you think about it because a partial knee replacement, if you only replace one section, you can get arthritis in the other section and then it needs to be kind of redone or have a redo on it.

So, the average length, you know how long does a partial knee replacement last? The average length on that is about 10-15 years, where the average length or how long a total knee replacement will last is 15-20 years. So, there’s a five to ten-year difference about there on average when you look at everybody across the country. And that’s again, that’s an average. So, some of those people are lasting much longer and it kind of varies. But yeah, you got to be kind of the right person for the partial and you got to understand okay, how long is this potentially going to last. You are getting a functional benefit where the knee replacement will feel more natural and work better, but it may not last as long as that total. And so, whenever I see patients and we are talking about this, I kind of – if I see on their x-rays they are a candidate for a partial, I talk to them about the pros and cons and we kind of hash it out about which way to go with that.

Bill: Well those are great factors to keep in mind when making a decision and there has been a lot of advancements in surgery, say somebody had a knee replacement ten years ago; now there’s a lot of new advancements like I was just saying. Can you tell us about orthopedic surgery and tell us about the use of robotics and sensors in knee surgery?

Dr. Balch: Sure, so there’s been a lot of changes in the way that we do knee replacements even in the last five and ten years. The anesthesia is much better the way we are doing them. People are recovering and walking faster. We are using combinations of medications that reduce the need for narcotics after surgery. We are doing special blocks that help numb things up after surgery to make it less painful and then there has been a lot of exactly as you said, technological advancements in the way that we do kind of knee replacement surgery.

The one thing is in robotics, people have started to use some robotics for putting knee replacements in to help guide some of the cuts. People are using things like navigation, meaning that it’s almost like a GPS for in your knee where it kind of helps you align the parts and figure out where the parts ought to be. And there’s even sensors. I use a technology where basically there’s a pressure sensor that you put in while you are doing the knee replacement surgery and it gives you the forces on either side of the knee as it is moving around. So, the way we used to do it in the past, was we’d make all our cuts, we would put in a kind of rectangular block in during the surgery and you would kind of wiggle the knee around and say yeah, that’s looks pretty good. That’s the way everybody has done it, that’s kind of the majority of the way people do knee replacements even now. The new technology with sensors is you put in that same block, but that block has digital sensors in it and there’s a computer screen that says well on the inside of the knee, there’s 30 pounds of force, on the outside of the knee, there is 25 pounds of force and these parts are rotated three degrees and it gives you all this extra information. And that’s really helpful for helping to balance the knee.

You think when you take your car in and they rotate your tires, they are balancing it out and aligning everything. This is kind of the same concept, except in the knee. And the studies that have looked at this show that knees that are balanced in this way, they tend to have better motion, less need for going in to kind of manipulate or gain additional motion. People tend to be more satisfied with the knee replacements that are balanced on this sensor. So, the early data has been very encouraging for this kind of technology.

Bill: So, data collection then on the knee itself has become very important in really dialing that surgery in.

Dr. Balch: Yeah. Absolutely. Being able to get more information for me, while I’m doing the operation, is really helpful to be able to fine tune things. There’s a lot of finesse things to balancing a knee in a lot of the things that we do, and in the past, there was a lot of kind of just eyeballing it. We did the best we could with the tools that we have, but there are a lot of new tools that are coming out to kind of help us make that better. So, I have been working with that and continuing to collect data on the patients where I do surgery on and tracking their outcomes and all that as well. So, I’m part of doing all of that too.

Bill: And Dr. Balch, if you could wrap it up for us quickly. What else do we need to know about knee revisions and the latest technologies in replacements?

Dr. Balch: Yeah, I mean I think the biggest thing is that knee replacement, it’s a great operation, it’s a pain-relieving procedure to help improve function and if you are not walking well, if you are having pain, it’s loose, it’s giving out on you, or you are falling down, or you feel like something just isn’t quite right or was never quite right; that can be a good reason to get it checked out. The other thing I tell folks which not everyone knows, not everyone realizes that the knee replacement is meant to last 10-15 years. So, I have had some patients where they had their knee replacement done 15 or so years ago, they had been doing great and then all of the sudden it starts to not quite work as well, and they don’t realize that the plastic can wear out. If you go get that checked out, it’s pretty easy to see on an x-ray if your plastic is worn out and that can be a pretty easy fix. You go in and you just pop in a new plastic. You don’t necessarily have to take the whole thing apart and completely redo everything. You just redo the plastic and then you are back to the way it was when it was put in.

So, if you stay on top of it, it’s pretty easy to fix that. If you wait too long and it starts to damage the metal parts and all that, then everything has got to come out. So, I generally tell folks, I say if it has been a really long time since you have seen any orthopedic doctor about a knee replacement, it might be a good time to kind of get it checked out and just get an x-ray and make sure everything is doing okay.

Bill: Absolutely. Well this has been very informative Dr. Balch. Thank you so much for your time today. For more information, please visit www.dignityhealth.org, that’s www.dignityhealth.org. The is Hello Healthy a Dignity Health podcast. I’m Bill Klaproth. Thanks for listening.