Name: Fresh Allograft OATS® Technique for Biologic Resurfacing of the Patella
Uploaded: 2018-06-04T00:00:00Z
Channel: Arthrex
Description: Raffy Mirzayan, MD, (Los Angeles, CA) performs a complete resurfacing of the patella with a fresh osteochondral allograft. Dr. Mirzayan includes multiple technical pearls for donor and recipient side preparations.

<p>Raffy Mirzayan, MD, (Los Angeles, CA) performs a complete resurfacing of the patella with a fresh osteochondral allograft. Dr. Mirzayan includes multiple technical pearls for donor and recipient side preparations.</p>

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VID1-01280-EN | A | Fresh Allograft OATS® Technique for Biologic Resurfacing of the Patella

Raffy Mirzayan

Human

A video recording of a surgical technique on a live patient in an operating room setting or a cadaveric demonstration.

Eine Videoaufnahme einer Operationsanleitung an einem lebenden Patienten oder Patientin in einem Operationssaal oder eine Demonstration an einem Humanpräparat.

Operationstechnikvideos

Surgical Technique Videos

Gravação em vídeo de uma técnica cirúrgica em um paciente em uma sala de cirurgia ou uma demonstração cadavérica.

Vídeos de técnicas cirúrgicas

Grabación en vídeo de una técnica quirúrgica de un paciente en un quirófano o una demostración cadavérica.

Videos de técnicas quirúrgicas

Fresh Allograft OATS® Technique for Biologic Resurfacing of the Patella

This is a left knee. The patella. Tibial tubercle. This is the fibular head. I make a midline incision. Then create a lateral sleeve of tissues. I prefer to do a lateral arthrotomy, because most of these patients also have patellar instability and will undergo a medial patellofemoral ligament reconstruction. So I prefer to preserve the medial sleeve of tissues for the mpfl and therefore I do a lateral arthrotomy. I leave a cuff of tissue on the patella so that I can suture it when I'm done with the procedure. This is the patellar margin is right here. So just stay lateral to the patella. Carry this up to the quadriceps tendon. If a patient has had a prior arthroscopy they'll have a arthrofibrosis of the fat pad. And I typically release that to be able to Evert the patella easier. Which is what I'm doing there. And then if necessary, I can extend this incision further up into the quad to be able to release the patella and to be able to Evert it completely. I place these towel clamps around it. This is much like a total knee exposure, and I try to keep the patella as horizontal to the ground as possible. And at this point I use the calipers To measure the patellar height. The native patellar height is at its highest point in the median ridge. In this case, we're measuring 24mm. Typically it's either 24 or 25mm in height. So in the operating room I would use a bovie for this. But for the purposes of the demonstration I can use a sharp dissection around the patella. It's important to recreate the normal patellar height. So I'm going to shoot for either 24 or 25mm of height. Once I've placed a donor graft and fixated it onto the native patella. So my assistants are holding the towel clamps onto the patellar tendon and quad tendon. The patella is very fairly stabilized at this point, and it's horizontal with the ground. So I use a sagittal saw. And just below the articular surface is what I'm shooting for. Once I've made the cut, I used my my guide again to measure the height. So I am at I'm measuring a 12 millimeter here 12 millimeter there. And then as far medial as possible to make sure that I'm consistent all the way across. So this is about 13 on the more medial side. So I'll use my saw and just flatten it out. So patellar height here is 12mm. And then more centrally and then more medially. It's approximately 12mm now. So we're fairly uniform at 12mm. And just by palpation I can just tell that it's fairly consistent all the way across. And it's about 12mm of bone left behind all the way across. Now that this is prepped and we've made our cut on the native patella, we're going to address the patellar allograft and prepare that. We're going to turn our attention to the patellar allograft. You can see that all the soft tissues the patellar tendon and the quadriceps tendon have been dissected off of it. And ideally, I will measure the height of the patella at the most prominent point. And in this case, this is a 23 millimeter height on the patella. This was not a match to this particular donor. This is for demonstration purposes only. And ideally I'd like to make my cut in the donor patella two millimeters below the articular surface to make sure they have enough bone preserved for fixation onto the native patella. All right. So we'll be using the patellar clamp workstation to work and harvest the patellar allograft. It's composed of this base that will help hold the patellar allograft. And that is adjustable by by pulling this clamp. This is adjustable in height. And ideally, I'd like to place my saw through these windows on the side of the clamp. And that way it'll give me an idea of where how high I need to adjust this. I can adjust this height. Roughly where I want. And then at that point, this adjustable arm on top of it can come down and help stabilize the patella in the workstation temporarily. So place it right in the center. And this gives you temporary fixation of the patella without any wires. Before clamping down with the jaws to hold it in place. All right. So at this point we have the patellar allograft securely fixed in our clamp. The bottom plate is holding it in place. This the adjustable arm on top. It's holding it in place. And the teeth of the clamp are really is what's securing the graft to the clamp. I'm going to move this leave adjustable arm out of the way and then place the saw through the windows. And this gives me an idea of where my saw is going to be and where the cut I'm going to make. And I'd like to preserve about two millimeters of bone below the articular surface. So I'd like to preserve approximately two millimeters of bone below the articular surface, which I'm very happy with that. Same thing here, with this, through this window and all the way around, I can see that my saw is going to be preserving two millimeters of bone. I think that is most priority. So the next step is to place this adjustable arm back onto the patella. And by looking at this window on the side, what these measurements tell us here in this window measuring 15mm is going to be the articular height of the graph from where I make the cut to the most prominent portion of the graft. And the number on top is how much bone we're going to cut away from the patella. So in this case it's eight millimeters. And as you recall the total height was 23mm in this graph. So eight plus 15 equals 23. So our measurements on this guide add up to our clamp measurements of the total height of the patella. Place the saw through the window of the clamp. So this is our allograft after it's been cut. I like the cut is perfectly parallel with the articular surface of the patella. Have enough patellar height or patellar bone behind the articular surface in order to support our cartilage surface of the patella. So this is our patellar allograft. After the cut, I measure the height again with the calipers. And we're measuring 14.5 or 15mm here, which is consistent with what we measured on our guide. So at this point it's very important to pulse lavage in the for the purposes of the demonstration we're using a bulb syringe. But in a in a real case I would use pulse lavage approximately three liters to make sure I get rid of all the bone marrow elements from the graft. So once the graft has been pulsed, lavage and then dried Now you just soak the entire bone graft and let it sit and soak while I pay attention back to the patient's patella. For the purposes of our demonstration, this is not size matched. This is the graph we're able to obtain. This is the superior surface of the graft. This is the inferior surface. So this goes on just like that. So in this case the graft is slightly smaller than the patient. But again this was not matched for this demonstration. So prior to placing the patellar graft onto the native bone I placed DBM onto the surface. This increases the contact area bone to bone contact area between the patient and the and the graft. Much like a mortar to bricks. So I just want to make sure my orientation is correct, that the graph is not rotated. And if I needed to, I could materialize the patella for even more stability, just like in a total knee. So at this point I take the smooth K-wires from the headless compression set, and I do it from the articular side and advance it all the way into the native bone. This ensures that I place the pins in the screws perfectly in the exactly the spot that I want, and takes the guesswork out of it. If I were to do it from the from the bone side. So I can check that my pins are parallel to one another. And I will advance these pins all the way out to the anterior cortex of the native bone. So you can see all the pins are then brought out the anterior cortex of the patella, and they stick up like this on the anterior surface. And we have very good fixation of our graft at this point. Okay. We've already drilled our holes for the screws and verified our length with fluoro. So at this point in this patient, I'll be placing a 16 millimeter headless compression screw in the most inferior hole. And I'm starting to get bite there now and feeling the compression. Okay. And a 16 is a 16 millimeter compression screw in the center hole. And a 14 on those superior hole. Good. So we're going to remove our guide pins here and check our screw lengths under fluoro. So we're getting a live fluoro shot here. You can see the interface of where we've made the cut and the interface between the allograft and the native patella and our screw lengths are appropriate. I don't want to go too deep into the allograft, so I don't aim to go to the subchondral bone. I typically just want about four millimeters of screw tip into the allograft component. In this case, the screws are totally acceptable. I could have placed them slightly more distal than where the three screws are now, but this is totally acceptable. I have good compression at the interface and great fixation. Once I'm I've confirmed my screw placement and the screw length is adequate and I'm satisfied with my fixation, I do a standard closure of the lateral arthrotomy. And if I have to do an mpfl reconstruction, I've preserved my medial tissues to do a standard mpfl in layer two and three.

Fresh Allograft OATS® Technique for Biologic Resurfacing of the Patella

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