Name:
Robotic-Arm Assisted Lateral Unicompartmental Knee Arthroplasty With A Fixed Bearing Implant
Description:
Robotic-Arm Assisted Lateral Unicompartmental Knee Arthroplasty With A Fixed Bearing Implant
Thumbnail URL:
https://cadmoremediastorage.blob.core.windows.net/c4c3db9d-00ec-40cb-b245-b054c633272f/videoscrubberimages/Scrubber_1.jpg
Duration:
T00H21M58S
Embed URL:
https://stream.cadmore.media/player/c4c3db9d-00ec-40cb-b245-b054c633272f
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/c4c3db9d-00ec-40cb-b245-b054c633272f/361486_Pearle_Knee Arthroplasty_Channel Partner.mp4?sv=2019-02-02&sr=c&sig=RQGChuYUnYH3qgXx7Cd1zdW8EKnz%2Bijfgv1Exds%2Fx3Q%3D&st=2024-09-08T02%3A11%3A55Z&se=2024-09-08T04%3A16%3A55Z&sp=r
Upload Date:
2024-05-31T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
ANDREW PEARLE: My name is Dr. Andrew Pearle. This morning we're going to be filming a lateral uni-compartmental knee replacement that is robotic assisted.
ANDREW PEARLE: So the purpose of this video is to review the indications and surgical technique for lateral uni-compartmental knee arthroplasty with a robotic assisted technique. This video details a surgical approach and the technique for the lateral uni using this robotic arm assistance as well as modern implants.
ANDREW PEARLE: The case today is a 57-year-old woman who's a runner, and you can see on her MRI now she has a big bone bruise in an area that we typically see with isolated lateral compartment arthritis, namely the more posterior aspect of the lateral femoral condyle and kind of centrally on the posterioral on the lateral tibial plateau. And you can see from the X-rays, lateral compartment arthritis is very different from medial compartment arthritis.
ANDREW PEARLE: It tends to be flexion disease. People tend to have pain with their knee in a flexed position, like in an athletic position or when they're going down stairs or getting off a low seat, they often feel instability rather than pain. So people will say that they can't push off on that leg or they really struggle going down stairs and the knee feels unstable. So these are very typical X-rays.
ANDREW PEARLE: You can see your patellofemoral joint is well maintained. You don't see much on the lateral and again, in full extension, she looks to have well maintained joint spaces. However, when she flexes for this Rosenberg or flexed knee notch view, you see the lateral compartment is quite tight. On her long leg alignment films, she's in six degrees of valgus. I plan on correcting this to about three to four degrees of valgus.
ANDREW PEARLE: This is a robotic assisted technique. With this technique I'm able to use CT based planning for the procedure and so what you see here is my pre-plan. I'm going to modify this plan intraoperatively based on the kinematics of the knee. So because of that, we have to rotate the lateral components so that they're congruent through the range of motion. Specifically, I internally rotate the tibia and you'll see when I put the femur on, I externally rotate the femur and because of this you get congruent implant tracking through the range of motion.
ANDREW PEARLE: So on the tibia what I'm looking for is good coverage, good cortical coverage, because these implants are not designed specifically for the lateral side, which is a little wider and shorter than the medial side, sometimes you have to be careful in the way you plan this and you have to make some compromises. I tend to put these in about 5 to 7 degrees of posterior slope. I like to match the anatomic slope as best I can, but I don't like to add more than 7 degrees of posterior slope because that puts undue stress on the ACL.
ANDREW PEARLE: When I plan the femur, I typically plan the femur to mate nicely with the tibia. If we look at the femoral position here, I've externally rotated my femur quite a bit and you'll see that I'll assess the rotational alignment when I look at my kinematic alignment, I try and match the J curve. And importantly, when I look at the femur vis a vis the tibia, I like the femur to be centered on the tibia.
ANDREW PEARLE: Proper patient positioning in OR room setup is critical. A standard MacKay table is used along with the De Mayo limb positioner to allow adequate flexion like you can see there, but I also want full extension. So this is a setup I like. I'm going to be on the right side, which is the operative side on this patient. The robot will be behind me.
ANDREW PEARLE: We've got a nice position on the De Mayo stand, so I'll be able to view the screen and we'll have the camera for the navigation arrays opposite of where I'm operating. OK, so we're doing a right lateral uni. I do a lateral para patellar arthrotomy. My incision is just above the patella, down towards the tibial tubercle.
ANDREW PEARLE: I put my pins in one handbreadth below the tibial tubercle and one handbreadth above the tibial tubercle and I put my pins in uni cortical. So I typically start by my pin placement, so the arrays then are placed perpendicular to the camera so arrays are nice and stable. Now we start the registration process. I'm going to bring the femur through this range of motion to identify the center of rotation of the femur, and then we identify the center of the ankle by touching down on the medial malleolus and the lateral malleolus.
ANDREW PEARLE: And then the computer can calculate where the center of the ankle is from those two landmarks. And we start the procedure, so again, I'm going just on the lateral border of the patella. And I make an incision down towards the tibial tubercle, and then I really use a Bovie to raise some flaps.
ANDREW PEARLE: I want to minimize the postoperative bleeding. So she's a small woman and we should be able to make a really relatively small incision on her. So for my arthrotomy, I feel the patella and so I can feel the lateral border of the patella and I go one finger breadth lateral to that starting just above the patella, I come down to the inferior pole of the patella, and then I look for the patellar tendon.
ANDREW PEARLE: You can see this is Gerdy's tubercle right here, so if I go straight down, I actually go through the IT band. So whereas I start out lateral to the patellar tendon and lateral to the patella, I quickly try and find once I get inferior to the patella, I quickly try and find the patellar tendon, which is right here and then I just dissect down on the lateral border of that and that keeps me out of the IT band.
ANDREW PEARLE: So if I put in this cerebellar, you can begin to look at and see the exposure. So again, what we have right here is Gerdy's tubercle. If your incision drifts a little laterally, you can go right through Gerdy's tubercle and cut the IT band. This is a fat pad and this is the anterior horn of the lateral meniscus. And so I tend to pick up on the anterior horn of the lateral meniscus and dissect down to its root and remove it by lifting up on it and transecting right at the level of the root.
ANDREW PEARLE: Another thing you can see here is the disease pattern. So in full extension, there's actually good cartilage as you bend down, you start to see her bone on bone disease. A normal lateral compartment has about 7 millimeters of lift off when you do a figure of four, so she's got excessive lift off. Importantly, when I put in the implants, I'm going to want about five to seven degrees of lift off when I do a figure of four like this.
ANDREW PEARLE: In the registration process, we're really trying to match the patient's anatomy to the CAT scan. The first step, once we're inside the knee, is to establish the position of our checkpoints so I put the green probe into the checkpoints. And what the computer is doing at this point is identifying the exact distance between the arrays and the checkpoints,
ANDREW PEARLE: so if the arrays move, that distance will be different and we'll know that something's gone wrong and we may have to re-register. The next process is to register the patient's anatomy to the CAT scan and so I'm going to pick a large number of points on the condyle so you can also see what I'm doing here is I'm adjusting my window by flexing and extending the knee.
ANDREW PEARLE: OK, so we've registered the femur, we're going to do a similar process on the tibia. It's important to create a unique shape here so the areas of the knee that have kind of a unique geometry like the tibial tubercle, I think are really useful when you're trying to register the patient's anatomy to the CAT scan. Now I'm going to position the leg in space where I want the knee to live
ANDREW PEARLE: at the end of the case. As you saw, she's in about five or six degrees of valgus in full extension. I'm going to reduce her down to about three. So this is where I want her to be at the end of the case and then I'm just going to hold the leg and I'm going to position the knee where I want it to be in space. I'm partially correcting
ANDREW PEARLE: so on the medial side, it's really ligament guided surgery. You're just tensioning the MCL and using that to guide where the implants are. So on the lateral side, I can really position this leg anywhere and I'm trying to estimate where she was before she got arthritis. Now we're going to do our astral planning. We've done pre planning based on the CAT scan. Now I've done my kinematic analysis and I'm going to refine my plan so that I get the alignment that I want, the congruence that I want and the positioning that I want.
ANDREW PEARLE: So this is my plan and at this point, we can bring the robotic arm in and execute the plan using the robotic arm to assist in this case. So the first step here is to confirm that the check point has not moved and therefore that the array has not moved.
ANDREW PEARLE: So that's our probe check, and then we want to make sure that the robotic arm is in space where the computer thinks it's going to be and so we have this check point for the robot. And now we can start to burr out the pre-planned volume of bone
ANDREW PEARLE: and you'll see I do a lot of adjusting to make sure that my window allows me to remove the bone and protect the soft tissues simultaneously. Flexing down again, defines my position and allows easy access to this bone in the back of the lateral femoral condyle. Onto the tibia. So we ensure that our array is not moved by checking our checkpoint, ensure the robotic arm is in the position, and the burr is where the computer thinks it is, and then we can do the same thing on the tibia.
ANDREW PEARLE: Now on the tibia, a couple things. I do start off in very modest amount of flexion that allows me to get the anterior cortex and to work underneath the patellar tendon, which again is kind of draped over the lateral side, and then I don't trust the burr by the popliteus so I always leave a little bit of bone right by the popliteus you'll see. And I knock that off with an osteotome rather than use a burr in that region.
ANDREW PEARLE: And you'll see as I move back, I'm going to preserve a little bit of bone right adjacent to the popliteus because I don't want this burr kissing the popliteus and causing damage. So this is like my little popliteus buffer right here. I'm not going to go any further. OK? And now I can do my post holes.
ANDREW PEARLE: So at this point, the first thing I do is I take out these checkpoints. Don't want to leave these behind. Checkpoint one, they're sharp so make sure that you treat them as sharps. I love this position, this figure four position, because you can see everything. The only problem with it, as a surgeon, you need some strong obliques because you're kind of cockeyed operating in this position.
ANDREW PEARLE: You can see with this view the lateral meniscectomy is pretty easy to do. So there's popliteus and you can do a complete meniscectomy and you can see now that our popliteus is intact. This is a popliteus. This is this little bumper. And you can see we've got a complete meniscectomy.
ANDREW PEARLE: So this is what we're hoping for. Resection, it looks like this and at this point, we can start to trial. So let's get our tibia and I put the implants in this figure four position. I feel that this really helps me put them in a really elegant and simple manner. A lot of times on the femur we have to kind of corkscrew it in, straighten out just a little bit, and we have to use flexion extension to help us get it in.
ANDREW PEARLE: Kind of jacks, jack knife it in. And then this is our 8 millimeter poly. At the end of the case now about 7 millimeters. Again, my finger is about 10/11 and it's not a full finger rest. So this is exactly the type of liftoff or opening that I like to see at the end of the case for a lateral uni when the patient's in a figure of four. Now, let's check our tracking. Perfect tracking.
ANDREW PEARLE: The tip of the femoral component is buried in the cartilage, so there won't be any patellar impingement and as I predicted, the alignment is about three degrees of valgus so three degrees of valgus right there as predicted. Nice stable knee during range of motion. This is exactly what I want. Drill, I always do
ANDREW PEARLE: drill holes in the tibia and the femur and I do that so that we can improve our cement interdigitation. Fixation is absolutely critical for partial knee replacement. So I'm going to put cement on the implants. I put very little cement posteriorly, so we don't need a lot of cement
ANDREW PEARLE: and then I'm going to take some cement and I'm going to manually push it into the bone as best I can. Again, I'm in the anterior two thirds. I have very little cement posteriorly. So that's about the perfect amount of cement for me. I'm going to take this, kind of flatten the cement out, make sure there's some cement around the keel and then find my holes.
ANDREW PEARLE: And then this is going to impact from back to front. I'm going to start in the back and then move it anteriorly so that most of the cement spits out the front. I use a Woodson and just use it to clean up the cement. It almost all is in the front. On the femur, which is a little easier to implant, I tend to put some cement in the drill holes, so extend just a little bit.
ANDREW PEARLE: And on the femur, you do have to of jackknife this in a little bit. I can see this hole, that hole so I'm going to put it in. So you kind of have to bend and extend till you can find those holes. I like to start in quite a bit of flexion when I'm getting the cement out of the femur so that I can get everything from the back first
ANDREW PEARLE: and as we extend, we've got much more access to the anterior parts so I don't really worry about getting the cement out of here. Anterior part of the implant at the beginning, that comes right at the end. OK. So that looks quite good on the tibia. On the femur now, reach around the back, get everything I can get. We'll take out the poly and now I'm going to look and make sure there's no more cement
ANDREW PEARLE: and by flexing the knee, I can get around all the way to the back of the more medial aspect of the implant on the femur and that looks really good. Nice access to the tibia, we'll put the poly in. OK. I can feel it lock into place posteriorly. OK. And now we just double check,
ANDREW PEARLE: make sure the poly is down and we should be in good shape. And again, we're in three degrees of valgus at the end of the case. Really nice tracking so tourniquet down. And then in terms of letting the cement cure, I typically do this in about 30 degrees of flexion right here. The closure is a pretty standard closure. On the lateral side,
ANDREW PEARLE: the soft tissue envelope is not quite as robust on the medial side so the closure really needs to be watertight for the lateral compartment. So I tend to close it in this position. So this patient should go home today.
ANDREW PEARLE: She'll be weight bearing as tolerated. Typically, people need pain pills, narcotics, anywhere from 72 hours post op to up to a week post op. She'll have a bandage on the knee. I don't like patients bending more than 90 degrees for the first week because I want to protect the arthrotomy. Most of my patients go back to sedentary jobs after a week or two post op. People do things like golf at six weeks and things like tennis at about three months.
ANDREW PEARLE: I do recommend 6 to eight weeks of physical therapy post-operatively to maximize their range of motion and to ensure that their gait is normalized and that their strength is appropriate. Thank you very much for watching this video. [MUSIC PLAYS]