Okay, so we're going to talk about coronal and axial plane alignment and when to do it. This is a big topic. I'll try to give it some justice. As you all know, coronal plane alignment, we're talking about valgus, varus, and neutral. This is just a really small vignette of a subcategory of my patients. This was 53 patients that I did a distalizing osteotomy for, for patella alta. I was just curious about their preoperative coronal plane alignment. Three had varus knees, 50 had valgus knees. And I just arbitrarily said 4 degrees was greater than normal, 4 or above. And of those, 14 people had valgus and 3 of the 4 re-injured their knee and 11 of 14 didn't. It's a really small cohort, but I do think that patella alta is often coupled with some degree of knee valgus. When do you have to correct it, I'm not sure. But I think that those with greater than 4 degrees may have a higher risk of re-injury. We need larger cohorts. Maybe the Jupiter study or maybe our Issacus study may give us some of these answers. This is a case of a 16-year-old female who had bilateral patella dislocations, lack of knee confidence, and had reasonable body weight. It had in between bait and score, but no knee hyperextension, which I think we need to separate out. And as you can see, had a mechanical valgus axis. She also had patella height, patella alta by nearly any measurement you wanted to use. And I like to use also just sort of a qualitative empty sulcus sign. When you see that first full cartilage coverage, you look up and there's no patella. Now this might have been a hard one to know what to do with, but in addition to all of her other problems, she had lateral compartment OCD, which interestingly was seen on x-rays since age 10 and never really discussed fully with the family. And so for me, this was an easy decision. You could stabilize the patella by correcting patella alta, and I don't think it hurts the patella by improving the limb alignment, and then of course treating the OCD lesion by unweighting or reducing that lateral femoral condyle load. And so for her, she got both a distal femoral osteotomy and a distal TIB tube. Here's another case of a 13-year-old. He had a primary patella dislocation with an osteochondral lesion, as you can see on that lateral femoral condyle. This was fixed, and then the MPFL was repaired. He did re-tear this, had a re-injury while doing some sports, but he was stable in his ADLs, and he could do some sports with a brace. When he saw me, he had a healthy BMI of 29, and he had chronological and bone age equal. This was his quick sampling. He did have a unilateral J sign on the affected side. He had bilateral genuvalcum, but his affected side was worse, which is his left side, and he had patella alta and a high TTTG as well. In his dynamic patella femoral physical exam screen, which I do for all of my new patients, he had knee hyperextension gait. He stood with his knees hyperflexed. He had a contralateral pelvic drop, functional valgus knee, et cetera, et cetera. My plan was to consult with pediatrics, and we agreed upon guided growth. He had physical therapy for improvement in body movement patterns. He had a fitness and dietary plan. He could continue to play select sports with a brace, and he had stage MPFL reconstruction after guided growth. This kind of shows you that you're treating the patient and not the injury. I thought for this particular young gentleman, it was really the right plan. When is genuvalcum necessary? Truthfully, I don't know. I think it's uncommon to treat it for instability in the adult unless you have a lateral tibial femoral joint at risk. This can be for cartilage lesions, meniscal pathology, sometimes OCD. And generally, I also look a little bit closer when it's unilateral lateral genuvalcum because I think that that side has already shown that you're going into more valgum. And generally, the weight-bearing line in zone two, I use a three-zone system, so you can see on your right-hand side, this is zone two. The left-hand side would be zone one. And I think that you could start to consider it. This is also something that the pediatric group uses as trying to consider guided growth. And it should be more common in kids with open growth plates. I think that I don't do guided growth, but I think about it all the time when I see my patients that still have open growth plates. Even more clear is the role of excessive axial plane alignment. Now, for patella femoral instability, it typically is increased femoral anaversion. Its role in J sign, when is it important, is becoming clearer. But is it necessary to correct for cartilage health? That's still a bit unknown. And for tibial torsion, it typically is increase in external tibial torsion. We are not clear about its role in patella instability, but it appears that it does have some role in patella femoral pain. And so, you know, what to do about torsion, when to de-rotate. These are the same patients in our hospital. We do all long-length films with the feet straight ahead. And you can see that if you have axial limb version, you can't say if it's femur or tibia, but you can clearly see you've hidden your lesser trochs and your knees are rotated. And this, on the other side, it's where the same patient, five minutes apart, with the kneecap straight ahead. So I still take it with the feet forward, and that sort of gives me a glimpse into whether there's limb version. It is difficult to measure. I think that in our country, CT scan tends to be the most used. In Europe, MRIs is becoming increasingly common. In our city, we are blessed with a good gait analysis, and for young kids, I often use gait analysis. This is something that our children's hospital started to use, but you can see that they do a very nice job of looking at coronal plane alignment up top and axial plane alignment on the bottom. And don't forget about femoral-tibial rotation, because it is higher in patellofemoral instability and does play into the role of the TTTG, which is kind of a funny number. The femoral version is hard to measure. I'm certainly not going to say which one to use, but just please know that your hospital should be using one that your radiologist can do consistently, and you should choose one because the numbers are quite a bit different. Al Geckert and I did a systematic review, and we looked at these numbers compared to a patellofemoral instability population, and as you can see, they're quite broad numbers, but in every situation, anteversion, external tibial torsion, and tibial femoral rotation, they are slightly higher in the patellofemoral population. I will also say that in our hospital, we only have two radiologists read it. If the number is greater than 30, we have the second radiologist overread them. I don't read them myself, but I do think it's really important that you have consistency in reading. When we let any radiologist read it, we were all over the place. Again, we can see that the J sign is this thing that automatically gets your attention, especially when they're this bad, but this is something that you should start to think about anteversion. Now, we have some recent studies that, again, give you an insight. This is one that looked at anteversion greater than 20 and less than 20, measured by a technique where the numbers are low, but they did show increased lateral patellofemoral cartilage wear when your anteversion was greater than 20. This is one of two studies done by the late Huang Feng from Beijing. He looked at high-grade J signs and femoral anteversion, dividing it into these three groups. In this study, he did an MPFL and a distal TTO, and he showed that if you had anteversion greater than 30, you had a higher rate of residual J sign and lower patient satisfaction. This same group did a different study, and they showed that when you had a high-grade J sign and femoral anteversion greater than 30, that even with the derotation osteotomy of the femur, you still had more MPFL laxity, which they graded by physical exam, and you had more patients with the residual J sign, improvement in the J sign, but not elimination. So J signs are tough, and even sometimes with trying to recreate a better anatomic situation, it doesn't always happen. This is a case report in our institution. This was a 13-year-old female with recurrent patella dislocations. She did have a Beaton score that did include knee hyperextension, and she had a soft J sign that relocated at 20 degrees. I show this because I've never seen anteversion this high. So her anteversion was whopping. Her external tibial rotation was also high, and you can see the other numbers here. So we did – I apologize for this next X-ray. I did this with Mark Dahl, who's sort of a super limb osteotomy person that I have the benefit of working with. And you can see here, this is from an EOS machine, so it's a little bit wavy, but he derotated the femur 45, the tibia 25, and then we did a revision MPFL. This is one way to do it. Here's another situation where it was a combined patella alta and increased femoral anteversion. This was a 20-year-old that had a hard J sign that relocated at 15 degrees, did have some mild hyperlaxity but not at the knee. Here are her numbers, and she did have mild valgus and patella alta. What we chose to do was to do a derotation osteotomy of the femur and tibia and distillize the tibia. When you use an IM rod at the tibia, you could have maybe done it at the ankle. You can do a distillization, and it's a little bit hard to work out the pins or the screws, but I've done this now about a dozen times. Now even more, taking one step further, is biplanar correction. You can do this with a single distal femoral osteotomy or a dual femoral osteotomy. These are tough, and I don't expect that you would come away, but I just want to point you to the literature and increase your thoughts. This was a complicated case. It was a dislocation, an obligate dislocation inflection. I did this with Al Gickwood when I went up there as a visiting professor, but you could see here that obviously the patella dislocates inflection, and they have a unilateral valgus. If you look at the torsion and the external tibial torsion and the femoral anaversion, torsion is probably acceptable on the tibia, but a significantly increased femoral anaversion on the affected side. There has been a paper that EMOF has written. These are two of them. One is a little bit more of a theoretical paper, but it does show that if you look at the sagittal slope on your cut, you can do either a valgus or a varus-producing osteotomy, and you can use this for small corrections. This is what we did. We did take off the tibial tubercle mainly to have better visualization and to kind of understand our cuts, and this was the end result. So it was a very satisfying alignment. I won't talk about the soft tissue reconstruction. This is her post-op, and I will say she did very well, but it was a long haul. She had stiffness. She had lack of motivation. I mean, these are big surgeries, but the end was successful. And I think this is from Canada, and they're a little bit more challenged, too, because they go great distances to a center that can deal with this kind of thing. This is a case report of another way to do it. So this is a 16-year-old that had an MPFL, and she actually had a J sign, and this was treated at an outside hospital with an MPFL and a distalization. I thought both surgeries were done well. I might have done the same thing. I'm not sure. But her J sign actually became worse, which rather surprised me. And so she again was then – this is not typical of my population, but so be it – dramatic J sign just went flying back into the groove at 15 degrees, and I'm sure that MPFL was like just pulling it back into place, and no hyperlaxity. And so here you can see that she had both some degree of coronal plane and axial plane alignment, and this was her previous distalization. And so the way that we chose to do this was to do two osteotomies in the femur. Distally, we did a lateral opening wedge. You can see the guided intermedullary pin. We used chance pins to hold – to set our initial plane. Then you define the rotation and hold it. And then we did an external cut with an osteotomy proximally, and this was the axial plane correction. And then we secured this with an intermedullary rod. And here you can see that you have your coronal plane correction distally and your axial plane correction proximally. And this was her final result. I only show this because I think it's actually a little bit better for bigger correction, and they're kind of in our toolbox, just usually not together. So the take-home message is that coronal and axial plane alignment is an evolving risk factor in recurrent lateral patella dislocations. Consider axial alignment when a hard J sign is present, and for those surgeons with a complex patellofemoral practice, the role of complex limb osteotomies is clearly evolving. Happy spring. Thank you.

coronal plane alignment

axial plane alignment

patellofemoral instability

alignment issues

management