quad lengthening, what degree of flexion do you reposition it in? Knee flexion. I'll answer that in two parts. I do think that as I've gotten better at lengthening the vastus lateralis tendon component of the quad, that we don't always have to lengthen the rectus component, the rectus intermedius. But when I do, I try to approximate it, kind of pull on the tendon on each end and approximate them together when the knee's in about 60 degrees of flexion. And if I can't easily get the knee beyond 90, if it looks too much tension, then I'll loosen it even more. But I'm a pediatric orthopedic surgeon, so maybe my kids, if they have extensor leg in four to six months, that'll go away in a year or two because they're growing. So it might be different for adults than for kids. Dan, do you think it's important to fill that void on the lateral side with the extensive lateral? You know, I wouldn't say it's a void, but I do think some sort of attempt to reconstruct the lateral patella retinaculum is important. I did a fixed lateral patella dislocation yesterday in a Down's kid, and I ended up using a tiny piece of gracilis just because there was a little tilt, and I couldn't save the lateral retinaculum like we usually did because it was too massive of a lengthening. Yeah, so my question is specific to distalization osteotomy, so I'm wondering for the panel, when you have that patient in first time traumatic dislocator, you try to rehab them and they don't get better, CD is 1.4 to 1.6, are we always going straight to the distalization if they're symptomatic, we can't get them better non-operatively, or is this kind of akin to an ACL where we're not doing a slope-changing osteotomy the first time, we're gonna do the soft tissue, make them fail that NPFL, and then have them fail that before we subject them to something that could cause a non-union and potentially do a bit more damage? So first of all, about patellar height, you have to be sure that you are doing the right measurement, so it depends on the rate of flexion of the knee when you take the x-ray, so that's the first point, because there's a lot of variability according to the measurement. There's some controversy between 1.2 and 1.4 factors, if you have more than 1.4, in that case, maybe not in the first dislocation episode, but in the recurrent dislocation, you have to lower the patellar height. But forgive me, I'm talking, so assuming the measurement is correct, and I know that's a big assumption, right, but we've done the correct measurement, 10 people looked at it, we all agree it's over 1.4, this patient has symptomatic needs of surgery. Are you going straight to distalization, or are you gonna try soft tissue first, make them fail that? Yeah, not in the first episode, you start with soft tissue, yes. I would not do an MPFL alone if you had a shallow groove, and if the patellar trochlear index was less than something like 0.2, I think the MPFL will fail. Although, if there's open growth plates, there are, it becomes more challenging. But if I had a first time dislocator with a katana 1.4 without loose bodies, I'm not sure it's a knee jerk that we're all going to operate on that first timer. They will be at high risk for recurrence, and when they recur, that's, I think, where your question is, whether we do isolate MPFL or add bone, and I think for the risk factors that I elucidated, that patient will probably have some of the ones that would make me do more. So I would do both. I think it's worth mentioning too, Miho Tanaka has some work, I think it's almost published, maybe published, in which she found that if you have patella alta and you do an MPFL reconstruction, that it's, as Seth said, Dr. Sherman, high risk for stretching out, so the higher the patella, if you just do an isolated medial reconstruction, you're running a risk of failure, which I think is consistent with everybody's saying. The objective, I would say. Hello, I have two questions. One is about the femur derotation osteotomy. So like, for example, Dr. Sherman, what would you consider an excessive femur inversion that would trigger due to derotation? Is that 30 degrees, 40 degrees, or it all depends? And then would you always use the CAT scan, virgin scan, to determine that, to quantify that, or you just use your prong position, kind of greater trochanter position for that? And the second question is more so for distal realignment for skeletally mature patients. Say if you have a 10-year-old or 12 with an open thysus, big open apophysis on the tuber-tubercle, and you do feel like you need to do distal realignment, but you cannot do an osteotomy, cannot do a TTO, then would you do a medial patella tendon transfer, like Jeff Napol and Lumen reported in WashU, or even the old school kind of roost-go-swap procedure, or you would rather stage it and just do other procedures and wait, and if it recurs, then add it on in the future? Thank you. I guess I'll take the second part first. So it's a great question about the TTO and the skeletally immature. I really think about it, again, with these two different types of patients. If it's a sports-related patient with a dislocation, and you would like to do a tibial tubercle because the elevated TTG or patella alta, in practice, what I do is I just do the MPFL because I can't do the TTO, and I don't do a Ruhl-Goldweit or a patella tendon transfer like the folks at WashU. However, in the syndromic kids, we do do the pediatric soft tissue type realignments, but not so, I haven't really done it in the active, athletic-type kid. What we do is we say this and said this, do you have risk factors that the MPFL might fail? Or your tracking may not be perfect, and once you're skeletally mature, we may need to have a second step. And I think that chance is low is what I advise the family. Maybe it's 10%, maybe it's 20%. But let's hope that you're one of the 80%, so let's go with the MPFL. Maybe, you know, so I'll leave it with that. The other thing is more than two or three studies have shown that an MPFL alone, especially a double-limbed MPFL, can reduce the radiographic measurement of patella alta. So it's something that might indirectly, you know, indirectly, you're improving patella alta a little bit. But I think you need to know whether you're doing a distal or medialization, whether you think you have a high Q vector, which I think would be more rare, or you have alta. I do think if you feel like you need to and the child has failed other ways and they've got three or four more years of growth, you could consider a patella tendon shortening. Jack Anders has not created this, but he certainly popularized it, and he has very good results. I find it's actually a little bit easier. I have better success in females than males, and I think for one reason only, that's females close their growth plates pretty quickly, about 18 months after their first onset of menstruation, which in the United States is, on average, age 11. And men have their growth plates open for quite a bit longer, and so I think that there's a stretch, or maybe it's a different hormonal environment. But when I do it in young males, they tend to stretch out more than when I do them in young females. Level five evidence. To answer your first part, I'd say many of our thresholds are moving and evolving targets, right? Typically for versions specifically, I want to look for several standard deviations above the norm, so I've never done one below a 30, and probably most of them are between 30 and 40. Clearly, I would not do it if the clinical picture did not correlate, so they have to have that kind of prone exam, plus minus the valgus. I want to measure multiple times and cut once, so I want to confirm what I'm seeing on kind of funny-looking X-rays that look like the rotation's off, and then CT scan with the protocols that we have, and then even one step further, putting it into the patient-specific system and seeing what their measurements come out and make sure it's that high. And then finally, if I have a different, more common bony pattern that I can correct and maybe just work around the rotation and or work around the trochlea, then I'm gonna strongly consider that. That's usually ALTA, I guess, would be my main one. And when you derotate the femur, do you derotate the tibia? I have not done both, and I don't know that I've, I know that I've not been clinically burned by it by someone's gait pattern, but I think, as I get more comfortable with any of these types of approaches and we have tools that we can measure precisely, I don't see that being that far off. I mean, double levels for other indications are coming, and they've been in other parts of the world for a long time. Yeah, several comments on that, if I may. I'm a stroke surgeon working in more like an adolescent and pediatric environment at DuPont in Delaware and New Jersey. And so in our experience, and one question that always came to our mind is obviously the cut of, better for femur inversion or tibia torsion is kind of just not a gold standard. But also if you look back to the so-called normal value, like you presented 15 degrees, 30 degrees, and if we think about that, where does that kind of gold value come from? Maybe from a long time ago where the CAT scan was not very popular. So that's probably based on your prone position measuring. So if you say something, you measure on a CAT scan, then there's a 30, 40 degrees. Is it really abnormal, or is it because the normal value we believe in was actually based on something that's not quantified by imaging before? That's one thing we're pondering on. And then for the tibia derotation, one argument that I heard is that, from my pediatric colleagues, is that if I do, the sports surgeon does the TTL, they think part of that actually correct part of the myorotation itself. So there's no need for us to do more tibia derotation in a formal way with a rod or a big plate or that. But some people do not disagree, sorry, does not agree with that. So that's one thing that I'm still thinking. I just want to know what your thoughts are. Do you think that TTL can correct the tibia derotation, tibia torsion, or not? I mean, I just had one case recently of a very complex syndromic where I wound up doing the valgus correction derotation on the femur. They had severe alta and a lateralized force vector still on the tibia, and to get it right, I had to continue to do some medialization and figure out to get to a normal tibial tubercle sulcus angle of zero, closer to 90 degrees. It definitely required both of those, and it definitely required some consideration on the tubercle. I'll tell you the osteotomy that I've been doing that John and I are doing biomechanical studies of his AMZ versus the one that I'm using now with a little different system, I do believe that it is a rotational-type component. The force vector goes from the tendon that way over that way, so it is, I think, to some extent, but I haven't looked at that specifically with post-surgical imaging to prove that we're changing any rotation of the tibia. Thank you so much. Well, I'd like to thank everyone for attending this symposium. We appreciate your questions, and it's time to move on as there's another symposium coming in in just a few minutes. Thank you.

quad lengthening

knee flexion

patellofemoral realignment

rectus component

tendon ends