Name: Options for Patellofemoral Reconstruction
Uploaded: 2021-11-17T00:00:00Z
Duration: 9 min 20 s
Channel: Arthrex
Description: J. Lee Pace, MD (Plano, TX), discusses options for patellofemoral reconstructions.

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<p>J. Lee Pace, MD (Plano, TX), discusses options for patellofemoral reconstructions.</p>

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VID1-002886-en-US | A | Options for Patellofemoral Reconstruction

J. Lee Pace

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Options for Patellofemoral Reconstruction

Good morning, everybody. Lee pace from Connecticut. We're going to go soup to nuts. Surgical management of patellar instability here. One thing I'd like to impress upon, particularly the fellows, is if you look at instability as the symptom of a problem, that's probably the best way to get at determining what the best treatment is. Like a cough is a manifestation of a viral illness. Patellar instability is typically the manifestation of some sort of underlying patho anatomy to quickly run through our sort of main players here. Trochlear dysplasia is the by far and away the primary most common cause of patellar instability, but we also have patella Alta. We also have femoral anteversion, and we also have genu valgum. And I'm going to go on a limb and say, I think the position of the tubercle as being a primary pathology is dubious. And I think we're going to continue to challenge that notion going forward. So again, we're not going to get into how to manage someone from the beginning, conservative management and stuff like that. But once we've indicated someone for surgical intervention, this is the algorithm. This is the thought process that I like to go through. So first off, identify the problem. What's the problem? Determine the severity of that problem. And based on the severity, is it mild enough that you can compensate for it. Or do you need to treat the underlying problem directly. And then at the same time, do we, you know, rebalancing the soft tissues on either side with the lateral retinacular lengthening and mpfl reconstruction. And the compensatory management usually is an isolated mpfl reconstruction with the lateral retinacular lengthening. If we're looking at anatomic specific treatment options, trochlear dysplasia, if it's bad enough, you can treat that with a trochlear plasty patella Alta. You want to destabilize the patella with either a distal tubercle osteotomy or. My preference is is what's called a patellar tendon imbrication. The problem with Alta is not a proximal tubercle, it's a long patellar tendon. So let's fix that problem. When it comes to anteversion and valgus, we will treat that with some sort of femoral osteotomy, be it a varus producing or rotational. And again all cases are going to get soft tissue rebalancing. And in my hands that's an mpfl reconstruction and lateral lengthening surgical indications for each specific problem. So for Trochlea plasty I definitely have a very European influence. So simply put, if BioTrochlea is flat or convex in my hands, that is BioTrochlea plasty. We published on this last year the lateral trochlear inclination angle as a quantitative method to determine dysplasia as opposed to du jour. A very good reliability. So once that LTI gets down to around zero, that's flat. That's usually a trochlea plasty for me. And just for comparison, a normal LTI is 18 to 20 patella Alta. This is really there's no clear strong indications for when to destabilize someone. A lot of the experts have said a KD ratio between 1.3 and 1.4. But I will tell you that's a little misleading. And I think that we should be looking at the amount of patellar trochlear overlap. So there is this publication by Roland Bidart looking at what's called the patellar trochlear index, which is a more functional measure of overlap of the patellar and trochlear cartilage. So usually something that's probably less than 10 to 15, maybe 20 will then be considered for some sort of distalization procedure. And this is the technique for a patellar tendon imbrication that you can see here. Surgical indications are even less clear in addressing anteversion and valgus. There is a paper out of Germany suggesting that anything above 20 degrees of excess anteversion may not be able to be durable with just an mpfl reconstruction. Men typically have adult levels of version of 8 to 12, and females may be up to 20. Generally, if someone has anteversion greater than 40 degrees, which I'm determining with a CT scan, that would be a primary rotational osteotomy for me, and I'm usually going to do that distal, because that way I can sort of have one surgical site, even if the actual difference in rotation is probably up at the proximal femur for valgus. What's published is literally a couple expert opinions that ten degrees of excess valgus would be an indication for a df0. I think that that's probably going to be more in the 5 to 7 degree range, but you can do a very nice opening wedge lateral osteotomy, which is my preference. So now let's talk about the Mpfl reconstruction to kind of get back to this, this talking point for a little bit earlier. So what's the rationale for doing an mpfl reconstruction. Okay. It increases the strength of the native mpfl. All right. This is an augmentation where making that mpfl stronger than what it was before and in isolation. That's to compensate for the mild to moderate patho anatomy. These people are not dislocated because they've got a primarily weak mpfl. They're dislocated because of some other type of patho anatomy that has caused the mpfl to become secondarily weak. Okay. If that patho anatomy is severe, then that mpfl is done in conjunction with treating the primary problem. You know, you treat the primary problem. The soft tissues will not reset themselves, so you do have to treat them. So in all cases this mpfl is going to be elongated incompetent. And we have to reset the tension briefly on the lateral side. In settings of chronic instability the retinaculum becomes contracted. You have this patellar tilt and translation. So this lateral lengthening as opposed to a lateral release allows you to reestablish length, prevent over constraint and also take away the risk of any iatrogenic medial instability. So I'll do a z lengthening lateral retinacular lengthening on all of my patellofemoral cases. We'll finish up with going through the technique of of mpfl reconstruction with current implants. It's AnaToemic. I do this v graph that you can see here. It's low profile. You get solid, bony integration. And this is something that I let my patients walk on right away. Full motion, no brace. Very, very reliable, reproducible procedure. Jake Jolly introduced the SwiveLock kits earlier today. Again, these three nines have the length of a 4.75, but a more low profile, which is nice for the patella. So let's walk through the technique. So we published on this just a couple months ago I guess actually last month in arthroscopy techniques. So I actually do this a little bit differently. I have a laterally based patella incision, and the reason why I do it that way is my approach is I can do a lateral lengthening through this incision here. So you can see there's the deep layer that I'm holding with the with the forceps there superficial layer. So I'll just do a lengthening as an initial approach. And then from there my incision is big enough that I can now easily expose the medial side of the patella. And you can see I can mark out where I want to put my patellar tunnels, and from there I'll place the K-wires. And this is nice. I will get my femoral site on x ray, so I'll place my K-wires. And then just before I determine my determined my femoral site. I'll check an x ray to make sure that my K-wires are in the patella. All the patella fractures have occurred with violation of the anterior cortex. So if you get well-placed K-wires and thus well-placed anchors, you're not going to get a patella fracture because you have not violated your anterior patellar cortex. And again here's these guides. You have a parallel or an angle guide that you can use. And then here's the femoral tunnel point. I usually cheat it in the posterior aspect of schutlz point. And you can use this guide as well to help you determine that. And I'll Overeem this. This is for me I use a TightRope. So it's a spade tip beef pen and I overeem it with a 4 or 5 reamer. And I'll make sure my graft can fit through that tunnel every time. And so here before I place my graft, this is what it looks like. I've got the lateral patellar incision the small medial incision. And then you can see my where I'm going to drill my patellar tunnels and my femoral tunnel. And then here's what the construct looks like. So I've got two, three, nine swivel locks. And then I've got a TightRope in the middle there. And for effect we put the trochlea plasty guide off to the side. A little artistic license there. So now what you're going to see is I'm going to place the three nine swivel lock, SwiveLock and I'm going to pull unnecessarily hard after I've got it placed, just to show you how how rock solid this fixation is. So the SwiveLock twists in very, very nicely here. You know, you can put that in no problem. And then I'll give it a tug again, way harder than I need to pull on that thing to demonstrate how how strong that fixation is. Okay, now here's where it gets fun is now that I've got this laterally based incision and I'm using a TightRope which is going to flip on the lateral femur, I can place the TightRope sutures through this beef pin, and I can pull it out the lateral side. And I can retrieve my TightRope directly out of my lateral incision, just like that. And now I can seat my TightRope under direct visualization so I don't have to worry about getting caught on the IT band or anything so I can watch it. I know exactly where it's going to be every time. Okay, that makes it very easy, very, very reproducible. And then my final tensioning is here. I'll put a little curve clamp underneath the the graft at the patella. Hold the trochlea. Hold the patella in the trochlea. Flex about 45 degrees. Keep it neutral. Tilt and translation. And then I'll tighten my TightRope. And I will tell you this. The concern is always over tensioning. I've in the 200 plus mpfl reconstruction I've done in the past four years. I've over tensioned three of them. So you almost never over tension with this technique and you don't get any graft damage from it. Very, very reproducible. And you get cortical fixation. And then at the end of the case I'll flex the knee 70 degrees, and then we'll sew the retinaculum back in a lengthened position. And you just take what's given to you. So here we probably lengthened a little over a centimeter. And I've gotten a minimum centimeter on all these cases. So in conclusion Patellofemoral instability, the algorithm, at least in my mind, is identify the problem and then determine if it needs to be fixed or if it can be compensated for. And we have anatomic specific treatments that are available that you guys should look into. And then I do encourage you guys to try out this new Mpfl reconstruction kit that's available. Thank you.