Dick for putting this whole thing together and for chasing us all down to get our presentations. I'm gonna give credit for this presentation to my partner, Sabrina Strickland, this is her case, and I'm actually gonna present it for her. So I added a few things so we can have a little bit of controversy, as we always should with Patella. So this is a patient who's a 13-year-old female, premenarchal, first dislocation was in kindergarten, three-sport athlete, and innumerable dislocations. You'll often have these patients who come in and say, my kneecap's been dislocating since I can remember. Physical exam, and I'm gonna play these because this is something I added here, but a physical exam showed significant apprehension, no end point to lateral check reign or translation, and a jumping J sign. She had a small effusion and a baton five, which I think probably means nine out of nine. So extreme ligament dyslaxia and a jumping J sign. So I'm gonna show you a video of mine, which is, we sometimes term it an obligatory dislocator, but this is, so this is somebody who is obligated to dislocate in full extension. She cannot extend her knee fully without dislocating her Patella, and that is what we call the jumping J sign, and so that's something that I look for. Let's see if the other one, this is more my video just to show kind of what an extreme or a significant J sign is, but it's not jumping. She's not dislocating. She's kind of riding laterally as she comes into full extension. And so this is the skeletal status. I think Sabrina puts on to show that when she had her first surgery, and we'll go through that in a second, the left side of the camera is where she was. So she was skeletally immature, including her apophysis was open. You can see the relative height. Oh, I guess the, yeah, so this is it. So this is her CD ratio, her catom de champs, 1.49, so very high, and also, again, as Jackie mentioned before, oftentimes you can look for the Patella trochlear index or the overlap in the cartilage between the Patella and the trochlea, which gives me a better idea of how engaged the Patella is in full extension, because really what we're talking about when we talk about ALTA is how quickly do they get bony containment. So if they're starting off at 30 or 40% that's already in the trochlea or overlapping with the trochlea, as they flex, they're gonna engage pretty quickly, and that's, I think, what we're really looking for with height. And this is the overlap, so a minimal overlap here in full extension. And then this is a measurement on how to measure the TTTG, obviously looking at the center of the tibial tubercle and then extrapolating it up to the center of the deepest portion of the trochlear groove. This can be done cranially at the very top, or it can be done caudally, distally. We've shown that there's not much of a difference depending on where you measure it, but you do wanna measure it where you have a full cartilaginous trochlea. And then the MRI, we have to remember, underestimates, based on some literature, the TTTG compared to how it was described, which was on CT scan, by about three to four millimeters. So we wanna kinda try to remember that when we have a TTTG of 15 on MRI, it's closer to 18 on CT. And this is the measurement of the lateralized tubercle. You can see this patient has a very high TTTG, but also I think this image is really telling in terms of where the patellar tendon is living relative to the lateral trochlea. So this is the PT-LTR, right? Where does the patellar tendon live relative to the lateral trochlea, because this is really another measurement of the extensor mechanism containment, and I think that's really important. And that's displayed here. So trochlea dysplasia, again, something that we wanna always classify when we're looking at these things. You can see in the way that we can classify it, we can certainly talk about the du jour, which I think is a wonderful measurement, and we can also, more than trying to classify the shape of the trochlea, we can actually classify the depth, which is displayed at the bottom, which is called the trochlear depth index, which helps us to kind of standardize between trochleas, how deep is the groove, and is there a groove that is going to be at risk? And you can see the varied trochleas that we have to deal with in this patient population. So the issues for this patient, they have patella alta, they have significant trochlea dysplasia, they have a lateralized tibial tubercle based on the TTTG, and open physes. So the options, which we'll talk about at the tables after this slide, brace and avoid sports, physical therapy, do an isolated MPFL reconstruction, or an MPFL with shortening of the patellar tendons, and she cannot have, she has an open apophysis, so you could try to address the alta by shortening the tendon. And then, obviously, the historical options of a Rube Goldwaithe. Hauser is not an option in this patient, obviously, because of the open growth plates. And so these are some studies that demonstrate the correlation in terms of outcome scores with chronic instability, and also cartilage defects, in terms of why we wanna fix these patients early. Generally, the thinking is that we don't wanna wait till they mature to try to address their instability, because the concern is, as they continue to dislocate, what we may end up with is a skeletally mature patient who has significant cartilage damage, and that's what we're trying to avoid, much like what we saw with the historical issues with the ACL when we tried to brace and protect these kids, and wait till they were skeletally mature. And we ended up with significant cartilage and meniscus issues in them, so we're trying to prevent that. And this is a systematic review, looking at 17 studies, the risk of recurrent dislocation, and this is what we call the prediction model, how likely is this patient to re-dislocate, and looking at their risk factors, and combining one, two, or three risk factors, you can see this patient has an exceedingly high risk of continued dislocation. So here comes the what's your plan? We'll leave it here, and everybody can start to talk about what they would like to do. Okay. Okay guys, I'm gonna continue this so we can kind of finish the discussion on this patient, and maybe even just open up more questions more than answers, but this is the plan, this is what was done. So Dr. Strickland said, decided to do a, I'm sorry, Dr. Strickland said she used all suture anchors in the patella, she did an NPFL reconstruction, and she used a suture anchor in the femur with a gracilis allograft. She fixed her in 30 degrees of flexion, and she thought that there was improved alignment of the patella, she did not do a patella tendon shortening, it's one of the things that we talked about, she did address it in her plan, and was thinking about it, and I think she chose not to do it in this patient, and to do the NPFL to give her a medial check rein in the hopes that that would contain her until she finished growing. I'm just showing a little bit of a different option, because obviously Dr. Strickland fixed her with a suture anchor, but to Jackie's point from her previous slide that she showed, in most of the time, based on the anatomy studies that we have, you can go underneath the growth plate and be fairly isometric, except in the extremely skeletally immature patients, I think, so that's something that's an option, is to go underneath the growth plate and use a socket, and that might, depending on how you are comfortable with fixation, a different kind of fixation than just a suture anchor. So 19 months after her NPFL, so she lasted a little over a year and a half, she redislocated playing softball, and the MRI was read as an attenuated medial femoral attachment, which you can see, and her bone age showed that she was now 16, you can also see the significant trochlear dysplasia, but interestingly, she's still lined up, she's not subloxed or off the trochlea, she's still pretty well lined up on the trochlear view, but you can see on her merchant axials that there's significant tilt and translation for this patient, and subluxation. So at this point, she addressed her with a TTO, she did an anterior medialization to correct the coronal plane malalignment, and she also distalized her because of the ALTA that we talked about on the earlier, and she used a tightrope for the femoral fixation, and when she did her distalization, she used an Evans wedge to kind of bring her down and give her the reliable measurement of distalization, which is a good technique. And she did a lateral lengthening at the same time, and you can see that well-corrected merchant axial. So the consideration factors that she had when she was addressing this case is to consider distalizing whenever you have somebody who has a very, and actually, David Dedick just made a great point at our table, ALTA is sort of a magnification, it magnifies every other problem, it magnifies trochlea dysplasia, it magnifies the TTTG, and so if you have somebody who has ALTA and they have significant instability like this obligate dislocator, you really want to consider bringing them down because it'll correct for a lot of those problems, especially if they have a big bump on their trochlea, you can kind of get them past that so that they never engage on that bump, which is really helpful. And then look at the TTTG and where the patella sits, and I think the other point from this to take home is that PTLTR, which I think to look at that and how the containment or the vector of the extensor mechanism is extremely critical to help us understand what things should we be correcting to keep these patients stable. And obviously in this patient, the major factor at the beginning was dealing with the skeletal maturity. Thank you. Can I ask a question? Yeah, absolutely. Do you know, I think that it was about three days, do you know if you can correct that the J sign was corrected with the neurosurgeon? So I do not know, I guess that's a good question. Can you correct a J sign with an isolated soft tissue reconstruction? Is that the question? Well, I mean, it's not too surprising it stretched out. I suspect that the J sign maybe was okay for a couple months and then gradually stretched out. Well, what was interesting about that too, you showed in, you had an MRI in full extension where she was located. Then you showed a virtual view, I think it was virtual, but you showed a low function angle where it was translated. Does that make sense to anybody? So that means that in full extension, you're located as you flex, you're going out. So to me, I don't get that, but maybe it's because you're quadruple contracting in one x-ray and not the other. So I mean, you have to think a little bit about, your patella should be most translated in full extension, and then of course it becomes more centralized. So I didn't really get how that happens, but I know people have that, but you have to think, huh, what's happening here? I would agree. I think maybe the merchant axial was done before her MPFL. That may be why we're seeing that, because the merchant axial may have done before, and that second MRI that we showed was probably done after her MPFL. I agree with you, they should look like mirror images of each other. Seth. So by the way, I think those are great comments, and I think what Seth's really saying is, in a patient like this where we can see what's coming, and we know that an isolated soft tissue is not gonna be this patient's last operation, is there more we can do with a skeletally immature patient? And it was brought up, David Dedeck brought it up at our table, or David Patterson, I can't remember, but if we had gotten standing alignment views on this patient, which I didn't see and weren't in the presentation, oftentimes if they do have a pretty significant amount of valgus, you can correct them with guided growth while they're open, which is really helpful, and may actually give them more containment as they grow out of that valgus and grow more neutrally. So there are a lot of things that are, like Seth is talking about, that we can do, including the patella tendon shortening and maybe a guided growth procedure that might give them better chances. Is that this abnormal patella tracking, to me is definitely the best clinical sign of a high-grade trochlear dysplasia. And in your patient, definitely we miss a little bit the sagittal view on the first patient screening. And this is definitely the biggest risk factor for this patient to have a patella dislocation. So in my mind, I would say that this is the thing that I want to correct on this patient. And I will, we cannot do that while she has a skeletally immature knee, but she's 13, so you can wait maybe one year instead of maybe doing one surgery with a failed surgery and go back to another surgery. This is my comment. And I'll just say this, is I'll take it one step further. In retrospect, this girl was done growing within two years of her index procedure. There is a study out of Germany by Nielitz, Manfred Nielitz, showing that you can do a thin flap trochleoplasty in a skeletally immature patient if they have two years or less of growth remaining and not get any growth disturbance. And I bet you I've done 50 and not had any observed growth disturbance yet. So I think in my mind, I would have done a definitive trochleoplasty MPFL, lateral lengthening, you know, with an appropriate bone age workup and all that stuff at the index time. Again, it's a very European way of thinking, very different here, controversial, I agree, but maybe it's worth talking about. Well, so here's the thing is, look at her, if that was her picture with her knee bent 90 degrees, the patella had turned the corner. It was parallel with the shaft of her tibia. So that, I still find MRI difficult for assessing height because the patella is out of plane with the central trochlea still. And so I will look at that, but then the other thing I've been doing, I don't know if it's right or not, but I'll bend the knee 90 degrees and I'll see where the patella is. If it hasn't turned the corner, then I say, okay, that's probably pathologic ALTA. This is level six evidence, right? But if it looks like it's turned and it's engaged and in line with the tibial shaft, I'm like, okay, that's not, that might be a radiographic artifact of ALTA and I wouldn't touch it in that regard. So if that's her picture, I wouldn't have done it. But if that was not her picture and it was still sitting up high, I would have imbricated her tendon. Immature or mature, that would have been my preference as far as procedure for that. This is good. This is good, right? I will say in my experience with the malalignment and the ALTA, if I'd have just been able to correct their trochlear dysplasia and an NPFL, that probably still would have failed. I think there's other things going on that still need to be fixed. The ALTA is still an issue and the malalignment with that PTLTR, because we're not gonna fix that with a trochlea. So I think that's still, the alignment still has to be addressed. That's, anyway. So let's go on to the next case. All right. Okay, so we're gonna, we're dealing with a lot of young patients here, but this is the instability.

patella dislocations

ligament laxity

jumping J sign

trochlear dysplasia

MPFL reconstruction