So this is a 10-year-old female. She presented to me with two instability events over a three-month time frame. The first one was a little more traumatic, rehab, brace, typical stuff. And then the second instability event happened while she was trick-or-treating. So now she's just loose and coming out. Always healthy female, wants to be casually active. On exam, she's got neutral alignment, cruciates and collaterals are fine. She's fresh off her instability event, so she's got an effusion, she's got some limited range of motion. Obviously, she's got patella apprehension. But the other thing that she's got is what's called this positive Craigs test, between 30 and 40 degrees. Do we have sound? We do? Okay. Now, I did not know what a Craigs test was until a few years ago, and I have to credit Lars Blond in Denmark for teaching me about that. And so I don't think most people know what this is, but this is now a routine part of my physical examination for anyone with instability. So I'm going to play my video here for a Craigs test examination. And there's no volume currently. Do I just have to... I can hear it faintly. Is there something else I need to do? This is what it is? Okay. So let me just try and walk through this then. So let me back up. So this patient, I'm starting with her prone, you can see. I have her knee bent 90 degrees. I'm with her foot straight up in the air, I'm palpating her greater trochanter, okay? And I'm going to rotate her foot back and forth until I can feel that greater trochanter at its greatest palpability. I can't think of... That's not the best word for that, but it's where it's most prominent, its greatest prominence laterally. And I'm going to move the foot back and forth until I reach that point. And then I'm going to basically look at the angle of the leg relative to the angle of the thigh. So there I am. I'm kind of pointing that, and this girl has normal rotation. She agreed to do this to be nice so I could, as I was prepping for this last year. But I'm feeling that greater trochanter. If someone's anteverted, their greater trochanter is going to be more posterior in this position, okay? Because their femoral neck is pointed very far forward. So to do this, I'm going to rotate her out. And if someone had really bad anteversion, her trochanter is going to be on its greatest prominence with the foot out more. And that's going to sort of bring that neck more horizontal. And that's going to be... This is normal version here. And then this is going to be here in just a sec. Wait for it. Build the anticipation. You can see me talking, talking, talking. I love to talk. And then soon enough, okay. So that would be a positive CraigsTest where that trochanter is maximally palpable with the foot way out there. Now that is not my definitive study. I will then... I use that to qualify anteversion. And then I will order a rotational profile CT scan to quantitate that anteversion, okay? So it was a potential pause spot, but we're going to go through this and then we'll pause and talk about it, okay? So x-rays. Now, different from David's comment earlier, you don't see that overlap of the tibial spine, but that's probably because she's really immature, okay? Her spine isn't fully developed, that lateral tibial spine. You can see at least a crossing sign. So she does have some degree of trochlear dysplasia on that lateral view. Mechanical access is neutral, maybe even a touch of varus. Her patellar trochlear index is about 0.4. And this is the article Roland Biedert published this in 2006. We don't have... We have normative values, but we don't know exactly what pathologic values are at this point, at least with rigorous clinical study. But I determined this to not be pathologic. I quantitated her dysplasia with what's called the two-image lateral trochlear inclination angle, which we published a couple years ago. A normal LTI is around 19 degrees. She came in at around 5. So she's definitely dysplastic, but she's not flat, she's not convex, okay? The TTTG, I honestly didn't measure this. I just put this in at 14 because I know people will ask about it. If we want to get really controversial, ask me about the TTTG. So now we measured femoral antiversion. I'll probably be replacing Bob Taiji's picture with Dave Patterson's picture here in the future. He's the understudy there. But I used what's called the Murphy technique. There's several, believe it or not, different ways to measure antiversion. And you do this often on two images as the lesser trochanter and the center of the femoral head, and measure that angle as opposed to just kind of going down the neck, finding that one slice with the neck, and then relative to the posterior femoral condyle. So here's this patient. I outline her femoral head on one image. I outline the lesser trochanter, the shaft of the lesser trochanter on one. I then overlay those. I take that angle relative to a horizontal, which was 48 degrees. And then a second image relative to the posterior condyles, which she had four degrees of internal rotation distally. When you do that math, she had 52 degrees of femoral antiversion. Sometimes you can get your radiologist to just kind of overlay all on one image, which is nice. This is obviously a different patient. At this age, at 10, most people are locked in on their version. So femoral antiversion for most females is somewhere between 12 and 20, males 8 to 12. So she's obviously highly antiverted. She's got some modest dysplasia. So here's our options. Let's take a second and decide what we want to do here. All right, guys, so we'll keep, we'll run through what we did here. So we have our list of stuff here. My personal take on these pediatric techniques, I actually, being the fact, even though I'm in a children's hospital, I actually don't do any of these, but we, and I think the trochleoplasty is, she's not severe enough to warrant that even though the dysplasia is there. So we opted for a distal derotational femoral osteotomy. She has a secondary problem of abnormal medial and lateral stabilizing ligaments because of her anteversion. So we do need to retension those with an MPFL reconstruction and a lateral retinacular lengthening. So here is the osteotomy. Those two little K wires are in the patella for the subsequent MPFL reconstruction. I have a freer elevator. You can see it's a little bit almost at the junction of the diaphysis and metaphysis. That is so that I get maximum bony contact after I derotate. If you go too far distal, the femur's not round there. And so when you rotate it, you get all this overlap and it doesn't line up as good. So I try to cheat a little bit more distally. And then by going more proximal in the skeletally immature patient, I also know that I can get my plate on and not be anywhere near the physis. And so I don't have, the plate's probably going to come out if it bugs her, but I don't have to worry about a growth disturbance from the plate. So transverse cut, I did not, Dave, I'm sorry, I did not use an articulated tensioning device here, but I think that Bob Taiji and Dave Patterson will speak to the benefit of really compressing these osteotomies. It really takes away a lot of pain from the procedure, and you can weight bear them on it right afterwards. But I derotated her about 35 or 40 degrees with a side plate, and you can see the relatively decent overlap there of the distal femoral shaft there. And then we did a physio sparing MPFL reconstruction. You see on the side view, it looks like I'm going to get into the physis, but like it's been said, if you just get an AP, you'll see that you're below it. So I will, and I actually cheat my femoral tunnel a little bit posterior because the graft is going to sit on the anterior aspect of that tunnel, so it's the same concept of a soft tissue ACL reconstruction, which I have Bob Arciero to thank for that. And that way, I think that I'm putting it more in the center. But we have this, we published on this technique for skeletal immature patients. This is what I call the kid's zone, distal to the physis, above blumen sats, and posterior to trochlea. That's a solid column of bone, so you can just put a pin all the way across that and not be in the physis. Okay, and then you can see on this notch view here how that is the case. You can see how distal I actually am when it looks like I'm getting into the physis on the lateral view, like blowing right through it, but definitely not. Okay, and then I do, I use a lateral cortical button now for my femoral fixation. We overnight admitted her. We did weight bear her. I think if I had attention to her better, we probably wouldn't have got that callus. Range of motion is tolerated. We started getting her back to activities at about three months. So there's variability based on measurement techniques. Patterson will tell you that this Widelook technique is the way to go. I've been using the Murphy technique. Maybe I'll switch. So you can see there's some variation in those. So you have to be consistent in what you're using to determine what your threshold is. And I don't, it's hard to say what that exact threshold is when you want to derotate. There's a biomechanical study showing that an excess of 20 degrees of antiversion may overcome an MPFL reconstruction. So if you've got a female with an upper limit of 20 and you add 20 to that, that's 40. That's been my typical indication for a primary derotational osteotomy. Less than that, I'll usually try and compensate for it first with an MPFL, okay? This other study showed that femoral antiversion above 30 had lower Kujala scores, et cetera, more MPFL laxity. They did not control for dysplasia, so it's hard for me to know what to make of that study. Where to derotate? You can do it at any level. I currently go distal because that's where the operation is. The deformity is probably proximal, but I think it, I'm not sure that it matters here. So thank you guys. And we can talk a little bit more if we want to have a couple more minutes, if we have time. Being a question of my people, I just wanted to get consensus from the leaders of the tables. Would anybody derotate without an MPFL reconstruction? Does anybody do, sorry. Does anybody do osteotomy and stop? Or does everyone add an MPFL? Add MPFL? Right. So you want to restore? Sure. Right. The primary restraint? Yeah. And this patient has dysplasia as well, right? So she's got some low-grade dysplasia. So if you don't compensate for that with the MPFL, I think you run her at risk of popping out. Now, if you completely correct every anatomic risk factor, Roland Byard, he actually switched, he doesn't, he, like if he does a trochleoplasty and he thinks all of his anatomy is fixed, he will then just placate. So if you don't compensate for that with the MPFL, I think you run her at risk of popping out. Now, if you completely correct every anatomic risk factor, Roland Byard, he actually switched, he doesn't, he, like if he does a trochleoplasty and he thinks all of his anatomy is fixed, he will then just placate. I'm not there yet. I still just do that insurance policy of an MPFL, but this girl would, needs an MPFL because she's still got that dysplasia sitting there. But, but I think you do have to, you've got to retention the soft tissues. Those will not reset themselves. And the literature I think has shown that at least in the trochleoplasty. So if you don't compensate for that with the MPFL, I think you run her at risk of popping out. Now, if you completely correct every anatomic risk factor, Roland Byard, he actually switched, he doesn't, he, like if he does a trochleoplasty and he thinks all of his anatomy is fixed, he will then just placate. I'm not there yet. I still just do that insurance policy of an MPFL, but this girl would, needs an MPFL because she's still got that dysplasia sitting there. of the last year's literature. Other, I think we're gonna try to move to the next case, but any other discussions from the tables here about that? Just to frame it, faculty, how many derotational osteotomies do you think you do in a year? Anybody doing more than five in a year? And is your anatomic threshold about 3540 as well? And it's mostly from me. Okay. And your practice is almost exclusively patella-femoral, right? Pretty high percentage patella-femoral for your practice. Just to frame it for the audience in terms of how frequently this comes in the door. I guess that's what I'm getting at. David, would things be any different in Europe, the approach for this, for antiversion? Personally, I'm not doing so much derotational stutemies, and most of the time I feel that I can correct locally the problem. For example, for your case, probably I would have more focus on the patella-alta than on the rotations, but it's definitely a good option, too, and I always combine that to an NPFL. Good. Awesome. So Andy's got a good case next.

10-year-old

knee instability

traumatic event

physical examination

femoral anteversion