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AOSSM Specialty Day 2023 with ISAKOS - no CME
5. AOSSM-ISAKOS - Innovative Techniques Panel - Ya ...
5. AOSSM-ISAKOS - Innovative Techniques Panel - Yanke
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Video Transcription
The next speaker, Adam Yankie from Chicago, to talk about managed distilling, tuberculosis anatomy, how I plan it, and what I do. Thank you very much. As mentioned, I'm Adam Yankie from Chicago at Rush, and it's really an honor to be here in front of both these societies. And Seth, that's an awesome transition to my talk, so thanks for your information as well. My disclosures are listed online. This talk is largely going to be an indications talk. I don't want to get into too much technique. A lot of that is online. I think choosing when to do it is important. This is some repeat of what you just heard, but this was a systematic review that we did looking at the risk factors that predict re-dislocation after isolated MPFL reconstructions. This is failure defined as re-dislocation. We saw that ALTA, dysplasia, and a J sign were all negative prognostic indicators. Most papers actually don't report re-dislocation. They just report poor patient reported outcomes. That added TTTG to the list. So now we have a few different factors that have decent amount of evidence behind them that if you have an isolated MPFL reconstruction, you might fail if you don't address them. We started taking a look at the exam under anesthesia that we did in patients where we slowly bent their knee and saw when dislocations would go away and you could no longer translate them. And if you couldn't dislocate their kneecap past 60 degrees of flexion, their outcomes with isolated MPFLs were significantly better than if you left that if you didn't address it and you did not do a TTO for instance. When we look at the drivers of what increases your likelihood to have increased flexion instability on EUA, one of the largest drivers was TTTG. And basically there was nobody that had instability beyond 60 degrees that didn't have an elevated TTTG and vice versa and they were all over 17 millimeters. Something else that we think about with ALTA is that the data for ALTA is actually pretty poor for isolated MPFL reconstruction failure and strict cutoffs really haven't been determined in a robust manner. But what we do want to see is that in our biomechanical studies, the length changes. If you look at that orange line at the bottom, that's at a CDI ratio of 1 to 1.6 and that's at the midpoint of the patella. The isometry or relative anisometry of the midpoint of the MPFC reconstruction on the patella or the most distal aspect is actually the same until you get to a CDI of 1.6. So I feel very comfortable doing isolated MPFLs and CDIs of 1.4 and below. You know, with these patients, you just get used to looking at all the factors every time and when you do that you'll get a better idea of what risk those patients have and it starts to get a little confusing but these cutoffs I think are important guidelines and if it's abnormal then I think about it. If it's not, if it doesn't mean I'm correcting these, it just means that they're part of the algorithm. It's also important to understand that these are really part of some global factors and local factors but the thing that's interesting about the tibial tubercle is that it really combines the two and so that's where the Venn diagram overlaps is the J sign and the TTTG because that's a measurement across the joint, takes into account tibial femoral rotation, dysplasia, valgus, tubercle lateralization. So it really covers a lot of ground and this is a nice picture of a patient I saw a couple weeks ago and the picture on the right is an AP of the knee so to speak and the one on the left is an AP of the tubercle and the patella is really going to follow the tubercle largely until it gets into some bony constraints of the trochlea which this patient really didn't have any. So the canary in the coal mine for me is the EUA instability beyond 60 degrees and a J sign of two quadrants. If they have those issues, something else is going on and I start to think about adding more than an isolated MPFL. If I do a TTO, a medialization is actually the workhorse for me for patella instability because most of my patients I'm doing a TTO on have a large TTTG, sometimes 25, even 30 and to be able to get to a TTTG of 10 which is usually my goal, you have to be able to translate quite a bit. So a straight medialization which is a flat cut of about 10 degrees so you don't accidentally posteriorize and it's a relatively posterior cut on the tibia and the sagittal plane so you have enough overlap once you move it that much. And so this is really powerful for correcting large abnormalities on the lateralized tubercle as well as large J signs. Straight anteriorizations are basically a cartilage osteotomy for me so I don't really do those in patellar instability. And then distalizations I do slightly differently. I make a chevron cut distally. I take that oblique piece of bone, move it proximal. It's basically switching the two and that gives you autogenous bone graft. It also gives you a stop gap so that piece doesn't migrate proximally. This is also helpful for people with trochlear dysplasia or abnormal jumping J signs because sometimes you can bring the patella around the trochlea, distalize and medialize it so it doesn't start out of the groove and sometimes that can improve that translation as well. There's many different ways to do TTOs. You can either use proprietary guides or freehand but I think that you just need to do something you're comfortable that's reproducible and that's really the most important component. An AMZ is the general workhorse and if you have, I consider that more like the 45 to 60 degree cut and if you have a high but not significantly abnormal TTTG or patellofemoral cartilage damage then this is the one that I would perform and it's the one that's performed the most nationally. So we really want to keep these limited. It should be about 5 to 10 percent unless you have a really high referral practice of the patellar stabilizing procedures you're doing and if you take this, I'm not going to go through this case because it's complex but I just want to show that you can have a lot of abnormalities. You can have valgus. You can have rotation. You can have a jumping J sign for a patient. You can have, here it is, the jumping J sign on the left. You can have instability and deflection and you can take this as well as all of the measurements that we take and it seems confusing but if you put them into those cutoffs, you start to separate things out into what really matters and what doesn't and then you figure out what you're trying to normalize and so a lot of these people, it's the J sign is something we're trying to normalize intraoperatively but we also want to get numerical correction that's within normal anatomic ranges. So for this patient, this was a revision MPFL reconstruction with a TTO first and you can see the video here as when we externally rotate the tibia, it causes a J sign. So there wasn't a J sign there. Now we do it and we see that you can get that jump and so if I do the TTO and I distillize, medialize, whatever it takes to get to a CDI close of 1.1 to 1.2, a TTTG of 10, if I still have that, then that's when I would add something like a trochleoplasty if they have a significant bump and I would say that that's, you know, even a smaller percentage than the 10% I was talking about with TTOs. So when we do look at the outcomes, Dr. Cohen actually has a study on this that was really good. It's a cohort between the two and it shows what Seth was mentioning as well, which is that if you have people with a TTTG of 17 to 20 and you do a TTO plus an MPFL, their subjective outcomes are better than if you do an isolated MPFL, even though redislocation rates may not change and the J sign improvement is significantly higher if you medialize the tubercle. So in summary, I think these are some general guidelines of what cutoffs could be to do isolated versus TTO and osteotomy surgery and hopefully that's helpful for indications and thanks again for having me. Thank you.
Video Summary
In this video, Adam Yankie from Chicago at Rush talks about managed distilling, tuberculosis anatomy, indications for MPFL reconstruction, and the factors that predict redislocation after the procedure. The talk focuses on the risk factors and the importance of addressing them in order to improve patient outcomes. Yankie discusses the use of the exam under anesthesia and the significance of TTTG measurement in determining flexion instability. He also touches on ALTA data, biomechanical studies, and the role of TTO in patella instability. Yankie concludes by providing guidelines for when to consider isolated MPFL, TTO, and osteotomy surgery. No credits were mentioned in the video.
Keywords
managed distilling
tuberculosis anatomy
indications for MPFL reconstruction
redislocation factors
patient outcomes
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