Well, good morning, everyone. Welcome to ICL 301, I think, on patella instability, yeah. So we've got a great lineup. We're gonna start with Jackie Munch-Brady talking about NPFL and getting it right and how to handle really difficult NPFL issues, too. And then Dr. Cascaria is gonna talk about tubercle osteotomies, medialization, distalization. Liza Rent is gonna talk about really complex deformities, valgus, rotation. I'm gonna talk about trochlear dysplasia. And then Sabrina Strickland's gonna talk about articular cartilage issues. I think we've got a great, great collection of talks here. We're gonna try to leave time for questions at the end. So we're gonna try to stay on time. So, welcome. Good morning, everybody. Thank you so much for coming. So I'm Jackie Brady. I'm at Oregon Health Science University in Portland, Oregon. And I'm delighted to be here with you today talking about NPFL reconstruction. So, Miho Tanaka and John Fulkerson, among others, demonstrated that this is complex. It's not just one discrete ligament. It has an attachment to the proximal portion of the patella and the distal portion of the quadriceps. And that gives us some options for how we reconstruct it. The femoral origin is the saddle region between the medial epicondyle and the adductor tubercle. And Philip Schottel taught us that the radiographic landmarks can reference the posterior cortical line of the femur and the condylar intersection posteriorly. But Corey Edgar demonstrated that if you don't have a perfect lateral x-ray, then that can be thrown off pretty quickly. So you really wanna know this anatomy well and do some double checks. We'll talk about those. Liza Arendt is here with us today and demonstrated that there's a high rate of failure if you repair your NPFL in a setting of recurrent instability. Perhaps there's a role in first-time injury, especially if you see a pure avulsion and not much signal in the ligament itself. But a lot of us will sort of default to reconstruction as our option. So how do we do that? It's the primary restraint to lateral patellar translation. This is where most of us start. Even for adding other things that we're gonna talk about today, this is where we'll start. So many, many ways to accomplish this procedure. There are free-tendon grafts. You can do one limb, you can do two limbs. You can do NPFL and attach to the patella. You can attach it to the distal quad, as Dr. Fulkerson prefers. You can do a hybrid technique where you do both. You can fix your femur first, your patella first, your quad first. You can use anchors, you can use sockets, tunnels. You can use quad autograft, we'll talk about that. You can use adductor tendon autograft. You can even use hamstring and do an MCL sling. So this is a lateral x-ray of a patient of mine. We'll talk a little bit more about other parts of her anatomy, but just a focus on the NPFL attempts here. There's signs of struggle on this lateral x-ray, especially on the femoral side that we'll talk about in a minute. But you want to attach the proximal aspect of the patella. I would say that wasn't done incorrectly here. But you start to run out of real estate if you're in a revision setting, and you don't want to make too many holes in a patella because you can end up with fracture, or just end up with poor fixation of your graft. So if you do run out of real estate, you're worried about convergence, you're worried about interacting with those other prior tunnels, you can attach to the distal aspect of the quad tendon, or you can take the quad autograft itself. So Christian Fink showed us that if you take the central, usually slip of the quad tendon and wrap it underneath, do a stay suture, then that can work well. This is Dr. Fulkerson's MQTFL. He does two slits in the quadriceps tendon and does a weave there. And then here's Christian Fink's construct. He wraps it underneath. So the femoral side is very important. This is the fulcrum of the circle. This determines your isometry. It's very common to be too anterior, too proximal. So you want to use your x-ray, but check your isometry, because if your x-ray isn't perfect, or if your anatomy isn't normal, so think about your hypoplastic lateral femoral condyle and what that does to a so-called perfect lateral x-ray. But here's a really exaggerated example. Let's say you were using this femoral fixation point for your MQTFL. That's your distance to your patella and extension, but as you flex the knee, you can see you're gonna stretch that graft, and it's either going to fail, or it's sure not gonna work, because it's gonna be awfully loose in that early flexion. So hold that thought on isometry. Let's talk really quickly about if you're doing this in a really young patient. We're recognizing that there are young people who would benefit from surgical intervention earlier, and sometimes you want to respect that growing physis. So we know that it has this central undulation that decreases in size as you get more birthdays under your belt. So that middle one is the most common sort of anatomy that we're dealing with in the skeletally immature, if you're operating on someone with patellar instability. But you can do this safely. So Nellet's described this way that you can angle your blind socket anteriorly and distally and use a sort of biotinodesis technique, if you will. You can also do a pull-through technique. There is a bridge of bone, if you look at that lateral x-ray, that's all the way across to that back portion of Blumensat's line. If you're careful about your trajectory, you can do a pull-through technique and not vary your technique too much if that's the way you like to do it in skeletally mature patients. So it can be done safely, and then if you just don't want to violate that physis if they're super young, or if they've had surgery before, if you're sort of running into trouble, then there are ways to do it without putting any bony insult on the femur. So the MCL sling is a way to take your hamstring and anchor it around your MCL. You can use your adductor magnus tendon itself. Petri Salampas showed us that technique as an autograft. And then you can use Dr. Arndt's technique where you use the adductor as a sling. These are nice options also if you're doing a distal femoral osteotomy because the end of that osteotomy, if you're gonna put it in the typical location, often violates where you wanna have a bony socket or tunnel. The thing is, you wanna know what this is doing to your anatomical location because, again, the femoral side is your determinant of your isometry. That's the fulcrum of the circle. And so I really recommend that whatever fixation technique you're using, you check your isometry. So this is rudimentary clip art on the left side. Forgive my artistic skills, but I've got two anchors in the patella. This is my usual sort of primary technique. I've got my pin in the femur. I do not use the tourniquet, so my videos are not quite as pretty as they could be. But you can see I'm wrapping the two limbs of my graft around that femoral pin before I buy that femoral socket. And so I've checked that location of the pin on the fluoroscopy machine that you see back there in the background to make sure that it's pretty consistent with Schadl's point. And then I wrap my graft and I make this arbitrary mark across all the limbs of the graft that are at the same sort of level. So if you squint at that picture a little bit, you can see the dark sort of methylene blue there. And I'm holding tension while I take it from zero to 90. If I see those marks move, then I know I'm not isometric and that graft is going to vary in its tension across the range of motion, okay? So you start range of motion. I just go from zero to 90. I'm watching that mark. You can see the mark isn't moving much and I like this isometry and I'm gonna buy that, okay? Shout out to Derek Bond in the background there. He's the resident working with me. He's doing a great job. Going into upper extremity, darn it. So if you need to fix your graft at the femur first or if you prefer to do it that way, then you've bought your isometry. Finds his MCL taking off, puts the point there. I'm not even sure he uses fluoroscopy routinely, but he fixes his graft where it anatomically ought to go. And then you check what your graft is doing with range of motion based on where you want to put it. So you'll clamp it at its distal quad. And if it's varying with range of motion, he tensions or sets the length. We sort of hate the word tension in MPFL surgery. The graft in the range of motion where it is the tightest so that it will only loosen from that point, if that makes sense. So you want to make sure that you're paying attention to not capturing the knee and over-constraining this thing because the bottom line is no matter what you're using to reconstruct this ligament, it is vastly stronger and stouter than the original part. So you have a real danger of over-constraint here. So here's an example of this. This is a pull-through technique. Again, Dr. Bond in the background there. He's gonna pull that thing into the socket. It's a pull-through technique. Now it's too tight. We've pulled it really tight. We're gonna let it be. We're gonna take our positioner out of there and take it through a full range of motion. I learned this from Dr. Desjardins. I like this because it lets the knee sort of set its own length, what it wants out of this construct. So you take it through a full range of motion and then you bring it to full extension and you're gonna check that you've got some translation in that patella and that you feel like that's a normal anatomical setup. And then you fix it at that length. So the bottom line here is NPFL surgery is not a surgery to pull the patella back into the groove. If you find yourself wanting to do that, chances are you should add something else and this is where I will segue to our other speakers to talk a little bit more about what to add. Thank you.

patella instability

lecture recording

NPFL reconstruction

recurrent instability

trochlear dysplasia