Let's talk about this patient. So a 32-year-old female, specific contact injury with patellar dislocation event four months ago. So relatively acute, no other issues prior, but did attempt PT for about three months. So again, no history of any patellar pain prior, no instability prior to this, but definitely had worsening pain with squats, lunges, bending. So again, more of a mechanical, functional type pain as opposed to rest pain, but definitely felt unstable with flexion and squats. So exam-wise, left lower extremity shows that she has a little bit loss of motion, not quite full extension, but no obvious effusion. She has tended to that patient pretty much everywhere, so one of those globally diffusely painful patients, but mostly on the lateral patella. Patella-wise, translates about two quartiles in extension, but did have an endpoint, but she has no patellar apprehension itself. So radiographs here. Does anyone really want to comment on what's going on? Again, she's 32, and these are the radiographs we're seeing today. So acute contact injury, but no other prior patellofemoral issues prior to presentation. Pretty subtle. When measured out, it's roughly the top side of normal, upper border of normal. So despite not having any problems, she definitely looks like there's some chronic underlying maltracking and whatnot, but no GSI on the exam. And MRI-wise? She had a little of that, on that lateral x-ray again, it's not normal, like that distal, like this here and that flattening is not, I feel like the lateral is a better way to look at it. The merchants, I don't know about your institution, but the reliability of a good merchant x-ray for me is not good. I got them to do good laterals now, but the merchants, I haven't fought that fight yet. And it's just so hard, the angle of the x-ray and the degree of knee flexion, I think it's, for me it's problematic making decisions from it, because I don't have reliability in the imaging itself. I do think it's worth looking at the AP, and I always point out to our residents, like if you see the sublux on the AP, the normally rotated knee, I think that means something. So I think if you put that together with the merchant, it's somewhat helpful. Although, to tell you the truth, Ellen Merchant would turn, basically, and squirm when he, if this x-ray is called a merchant view, right, because that by definition should be done at 30 degree flexion and not at 90 degree flexion. Yeah, it really does. I mean, just like your institution, it's really dependent upon the tech, and I never know which tech is back there, so. Alright, so, let me see if I can get the MRI to work. Okay. I wish I could slow this down, but get an idea of the axials. You can see that there's a, she's sitting probably a little bit lateral, probably tracking a little bit more lateral. Definitely a grade three to four lesion along the lateral patella, and then even a little bit of a kissing lesion onto the trochlea. So again. There we go. That's a good question. Do most people get MRIs for their TT, TT distance, or do they use CT? CT. CT, since he uses his own. I find MRIs fairly unreliable for my measurement. So what are the routine measurements that you guys are getting on these patellofemoral patients? I mean, you know, we're all in clinic, clinics are busy. You know, are there certain routine measures that you guys are basically getting on everybody just to make sure you are crossing your T's and dotting your I's? So I'll always measure the TT, TTG. I frankly do it mostly off MRI because I always have an MRI. And so, and again, I had a lot of young patients, I do try and be sensitive to the radiation. Laterals, you know, patellar height. So always, always looking at that. And I do get long leg alignment films on everybody too, especially if you're doing it in the tibiafemoral compartment. Sabrina, what do you do at IHS? Speaking for the two of us, but we pretty much never get a CT unless we're looking at version. So if we have real concerns about version, we'll get a CT, but I would say that's 5% or less of patients. We measure TT, TTG on everybody, and then we take a quick look at the sagittal and look at overlap. So if their overlap or their index is reasonable, 30 to 50%, we don't measure catondrochomp. Otherwise, we measure catondrochomp. And the only time I measure that sagittal, TT, TTG, is because that takes another two minutes, is if there's a secondary cartilage lesion and I'm thinking that I'm going to alter their tubercle height. So not every osteotomy, but it's something I look at, especially if their TT, TTG is normal. Jeff, what about you? I agree with the long leg film. I think it's probably... The long leg film has been really helpful, because I think I surprise myself sometimes just how much of an algus somebody is. We started doing this about five years ago. We've done a dynamic component to the CT that's really changed my mind a lot about my opinion of how much somebody, exactly like... I think you'd be surprised when somebody fires their quad, how much more lateral they shift. It's pretty impressive. And I've had people dislocate just on a table in full extension. So we do a CT at 45 degrees, 30 degrees, and then firing their quad at zero. Pretty impressive. That's a great tool to have. Not everybody has that. So the one thing that I would encourage people to do, just as an exercise, right? I never trust just one measure for one factor, right? TDDG, I do on the MRI typically, and I compare it to my TTPCL. If they point in the same direction, and they are both pathologic, then I buy it. If they are not, and sometimes you may find that they are borderline, or they may even go in opposite directions, the one indicating pathology, the other one not, then I don't buy it. And the same thing for patella alta, right? Do you do the Caton ratio? I think that's what we do in patellofemoral surgery, that you can actually use to measure your transfer if you ever do one. And the other one is the patellofemoral engagement index, which is what Sabrina was talking about. How much overlap do you have as maximum overlap between the patella cartilage and the trochlear cartilage? Again, if they point in the same direction to pathology, then I buy it. If they don't, I don't. So I think this is just basically doing a little bit of checks and balances. But those are the standard measures that every one of my fellows has to present me with if we are talking about a patellofemoral patient, just so that they're very comfortable with it, because I think this is necessary to understand some of the basic alignment of the patellofemoral joint and takes a little bit of the guesswork out of it. So one thing with the sacral TTTG, looking at that relationship of the tubercle and the trochlea, because we've had a couple studies now that highlight that it does seem to contribute, when you're measuring your TTTG, if that's posterior to your trochlea, then that's saying your tubercle is posterior. So even if you don't measure that vertical distance, you can at least say, okay, I'm at the level, I'm below it, or I'm anterior. And I think if you're at or anterior, you may not need to anteriorize as much, but that's still something we need to figure out more. But just do a quick check of where that lies. We need to write better. That was Drew's fault. The fellows don't do any of the work at Rush on the papers, so I don't know what you're talking about, actually. The other thing that I think is tricky, so you're talking about CT and MRI and the TTPCL, or you could do lateralization of the tubercle. And I had two patients recently that I had an MRI. I thought they needed derotational osteotomy. Their TTTG was 20 on MRI. On the CT scan, it was 12. And then I started looking into it, and my techs were positioning the feet differently in the scanners. So when you look at the studies that look at CT versus MRI, they're done prospectively. It's the exact same positioning, and now we're talking about a few millimeters difference because of maybe how you view the cortex on an MRI versus a CT. But we have a study recently in AGSM, and Lee Pace did it independently in their group. And we found different factors that contribute to an increased TTTG, but our first factor in both papers and everybody else that looked at it before us is knee rotation angle. And so the position of the femur relative to the tibia, so the rotation within the joint, is the number one determining factor of how big your TTTG is. And you can't have a large one without having knee rotational abnormalities to some extent, which you obviously can't fix surgically, but it's dynamic. And so you don't want to hang your hat on the measurements alone. They're good guidelines, so they're good for safety nets. And it's like when you're bowling with kids, you shouldn't just treat everything on the number alone. Fair enough. So are you guys thoroughly confused yet? Do you want to resolve this and tell us what you did? Well, what should I do? I don't know. I don't know. I put some guardrails up. Hopefully it worked. So the first idea was just to scope, or get an idea of what's going on with these lesions. So these are the lesions. Just to really... Because MRI can be suggestive, so this is what we see. Lateral facet looks like it's probably grade 3. It's a 2x2 lesion. On her trochlea, on the lateral trochlea, she has proximal lateral trochlea. It's a 2x1 lesion. Much bigger than what it probably looks like. 30s. Early 30s. Any ideas what you guys would do based off this? So options would be anywhere from your cartilage regenerative, so you can microfracture or microfracture plus. You can look at osteochondral allografts. You can look at the surface-based allografts. So chondral allografts, anywhere from putty to juvenile cartilage to potentially laser-etched cartilage or a kind of cell-based therapy. And in terms of procedures, anything to do in terms of unloading. So the clear picture seems like most of us will unload regardless of what the stability is or where the lesions are. So this is a kissing lesion. So unloading is most likely in the cards. The question is whether or not MPFL is necessary even though she's a little loose and she doesn't really have true apprehension. But the question is, her patella obviously is doing something on the lateral facade, so trying to figure out what to do with that. And then what do you guys do with her lateral retinaculum? Is that important or is that not important? It's just soft tissue on the side to adjust. Anytime I do a TTO, I do a lateral retinacular approach and I automatically lengthen the lateral retinaculum because if you do a TTO, even if you do an anteriorization, your retinaculum has to get longer. And so I just do a retinaculum splitting approach like Jack Farr popularized almost a decade ago and that works really well and allows you to repair it nicely afterwards. Volleyball. She loves playing volleyball. Just on the lateral retinaculum, I'm probably a little bit less aggressive about lengthening but I check the tilt and drop and I look at the tracking and make sure that it's not tight. But if it's more chronic and if they're older, that lateral retinaculum can be a big problem in terms of its stiffness. So what do you accept in terms of tilt? We talk about these, but the reality is the devil's in the details, right? What do you consider abnormal tilt and what exactly is that? I have no measurement in the OR. Does it look pretty good? Yeah, so what does it feel like? Does it go to neutral? Can you evert it? Can you flip it over? Neutral is a bare minimum for me. I think it's important. I check in the office, but I definitely check in the OR making sure with one hand you're centering the patella and if you push down on the needle to set you should feel it tip up a little bit laterally. If it doesn't, then I always do a lateral lengthening. If I'm doing cartilage at the same time I almost always do a lateral approach with the lateral lengthening. You have to get in there somehow and then you just reach across the top to get the ability to do that. And the advantage is if you don't use it then you just put it back where you took it from. Even releasing the deep layer as Karina talks about releasing posteriorly that in itself and you put the outer layer back together even if you do that that will unload that lateral facet but you've got to release laterally in this case. This is a kissing wing It's not going to do that just doing this on a regular basis. Then the question is 30 year old wants to play volleyball. Okay. You can knock this out of the park. You can go back and do that. So you're saying you would go if you're going to do something to the legion make your incision lateral but instead of going just through do a Z You basically do a vest-over-pants preparation so you do a proximal or an anterior cut then you try to separate the layers and then you do a deep cut to it and then you basically the retinaculum laterally is only about the same width as an MPFL it's only about a centimeter and a half wide if you really prep it down and the rest you can cut and then once you're done with your preparation you put it back down and then you do exactly what Sabrina says you see where your patella wants to be and then where that retinaculum comes together and then you just lengthen it side to side wherever you need it Can I ask one more question? I don't mean to deviate from this case but if this woman had more history she had a couple of instability episodes but if you're going to do the TTO for this does that make it less likely that you would have to do the MPFL? When I first trained every instability just got TTOs and most of them seemed to do fine but if you do a TTO Show of hands then I think that's a great discussion point who would primarily she's 32 never had a patella dislocation previously you're going to be in the operating room who would do an MPFL on this patient versus just the TTO I would do an MQTFL that's what I've been doing not the TTO but the MQTFL it's a good augmentation with instability she had instability no prior instability but she had the instability to cause this once she's had the instability I'm going to do something because if you're going in anyway there's a history of patella dislocation that I think becomes much more likely there's no history of patella dislocation I can't recall any case where I hadn't had an MPFL if there had been a history do you think the TTO potentially could be enough how much do you trust the history though too like on her MRI she had no lateral bruising I mean it looked more congenerative than anything else I mean I think that a lot of people come in and they say oh my patella dislocated but it really may have been a little subluxation or something like that there's all kinds of instability when she flexes when she moves right but the reality is like how much is this the two kissing lesions that are now symptomatic I don't see if her dislocation was two or three months ago you should still it's an acute dislocation you should see something now I'm like do I have to say anything about the MPFL, darn it, I don't know so I think the more I tease into it I think she actually did have instability prior so that's where the degeneration actually came about so what I did was basically I did an osteotomy to kind of unload, centralize not medialize right, centralize it I did a lot of retinacular lengthening just because of the kissing lesions on the lateral side of it and I didn't do an MPFL because she was actually unstable when we tested her so a lot of times I'll move the TTO over and then I'll just reassess and see what her patella is going to do from an MPFL standpoint and so that's what was done and I know they talk about, a lot of people here talk about going laterally and just kind of flipping everything over I actually just go off both sides of the retinaculum on medial and lateral patella and just flip the whole head up, just for exposure so Rehabilitation wise, did you slow it down, kissing lesions I mean, what do you Yeah, I think it's pretty standard, touchdown so I kind of go back and forth with my TTOs in terms of touchdown weight-bearing versus weight-bearing tolerated in extension so because of my concern about really shutting down the quad What about the range of motion, what do you do with that? It's pretty slow, 0-90 by about 4-6 weeks So you're pretty standard range of motion on the kissing lesion Yeah Do you do something different? Yeah, with kissing lesions I would slow it down significantly I mean, I'd actually increase the weight-bearing immediately with these I'd go touchdown 25% immediately go 25-50% at 2-4 weeks pull at 4 weeks with the locked out straight, but with a kissing lesion I would limit flexion for the first 4 weeks, I wouldn't hyper-flex I'd be concerned about that I would allow flexion but then limit your range so I'd typically go 30 degrees, 45, 60 and gradually work up towards 90 but I wouldn't go hyper-flexion quickly with this one because you're going to go right into that site you got selfish Yeah, so let me actually correct kind of what I'm saying so I actually don't actively let them do flexion to 90 I'm sorry, not passive but I actually let them do maybe 1-2 times a day with passive assistive flexion at 90 to help kind of break up some of the scarring that's going to want to occur, but most of the motion is actually through CPM, so I go pretty slow 0-30, and then so up to about 60 by about 4 weeks yeah, yeah but the key is I think passive flexion assisted once or twice a day just to help break up that scarring so you don't get that arthrofibrosis and just because of the extensive dissection for the TTO to flip the head up that's a concern, I don't want that to get stiff I'm not as worried as much about arthrofibrosis in this situation as long as they're locked up they have full extension I can get the flexion pass 90 back eventually anyway, I mean either way and those typically have great dealing with arthritis how many people are routinely using CPM? trouble getting CPM right, it is, they're disappearing like in my area, literally my DME guys have there's two units left they actually had to go dig them out of the trash because I was like where the hell are the CPMs so, yeah, they're disappearing

patellar dislocation

cartilage regenerative procedures

unloading techniques

osteotomy

rehabilitation protocol