We're really going to talk about distal procedures, so I have no conflict. So basically just trying to get an idea of when you should do a tibial-tubercle osteotomy. And interestingly, these are not just for instability. So we often talk at the meetings about instability, but there's a lot of other things that go on in the patella including chondral defects and osteoarthritis. So for instability, obviously the classic article from back in the 1990s, which basically shows the reasons for instability. But also a lot of things we see in the office are not frank instability, patellar maltracking, subluxation, and then obviously dislocation. Here's a poor guy who is not very happy. So a lot of this has been covered, so I'm going to kind of move on. Interestingly, they've been doing trochleoplasty since 1891, so that's not really a new topic. But it is, I think the indications in the surgical procedures continue to get better and I think will probably continue to increase. Patellar ulta, again, the only factor which really could lead to patellar dislocation without trochlear dysplasia, which was kind of an interesting comment. But here's a study from Magnusson, which basically showed for patellar ulta, distal procedures, only recurrence rate of about 0 to 4.9%, although they still did have apprehension. Here's a classic technique, and Andreas gave an excellent review of that this morning at the ICL, so I won't go over that. Isometry of the medial patellar femoral ligament, I thought this was a good study, which basically shows that obviously we know that the patella with patellar ulta engages later, so it's less stable. The key thing is that this anatomy, if Jack can say that for us later, that'll be good. What Jack's saying is, I think, and Tony's skepticism, we're basically saying that early in the range of motion, the MPFL is isometric, but not so much later. So it really is important where we put this position, and this has all been gone over before. But the bottom line is that in a good study by Riddler and Bass-Schubenstein, basically what they showed was is that if you have an increased TT distance, or you had an increase in your CD ratio, that that ligament has to get longer, so it's less easy to reconstruct the MPFL with an increased TT distance and an increased patellar ulta. Another point I think that's important, these guys are experts and they make it look pretty easy where to find that position, but in a study where they looked at that, only 69% of the femoral attachments were in the right place. So risk factors, TT distance, we had good pictures of that before, all this is kind of review. But my mentor, John Fulkerson, basically says that if the primary problem is secondary to a vector abnormality, you've got to correct the vector abnormality. So I kind of like this, you can't pull the patella into place, but you can hold it in place, so if you're going to try to push the patella into place, you need to go distal. If you're trying to hold it, you can go proximal. So TT distance usually over 20 need to be addressed with the goal of a permanent correction with balanced tracking of the patella. So here's a good study from my friend Jim Bradley, took 41 patients, all athletes, and did TTO with those patients. He did actually also a lateral release, which I don't think is necessary usually, and only had one recurrence, and that was a patient who actually had Ehlers-Danlos syndrome. And the other thing I think that's important is that you decrease the patellar contact pressure with a TTO or Fulkerson osteotomy, somewhere between 8 and 15% decrease in that contact pressure by correct realignment of the patella-femoral joint. So I think it does decrease the patella-femoral contact pressure. I do think that for the patella-femoral contact pressure, you have to be careful. A poorly done MPFL, I think it clearly increases the contact pressure as Redler showed us. So you have to use a TTO, I think, to buffer the forces to try to put that patella in the correct position. And lastly, patellar articular surfaces. I think depends on your TTO, at least in my mind, has to really be engineered and constructed individually, I think as these authors have said, because you certainly don't want to shift the patella onto an ebernated surface or an unhealthy surface. So if you're going to shift it, then you've got to either shift it onto a good surface or make the surface you're shifting on a good surface with a cartilage procedure. So TTO, unloading the patella, that's an old study. But back to Beth Schubenstein's article, the TTO, I think, is unparalleled in terms of the flexibility to treat multiple conditions, TTL alone for maltracking, TTO alone with soft tissue procedure for instability, and cartilage restoration. I think the key for a good, a well-done TTO or fulcrum osteotomy is to determine whether you want to shift it medially or you want to shift it anterior medially. So if you're going to just shift it medially, you can have a relatively flat osteotomy, which I'll show you a little later, outlined with drill bits. If you want to do it steep, or if you've got DJD, do it steep. So in conclusion, I think this is certainly something a PF surgeon needs to have in his or her armamentarium. I think you need to understand the versatility of the procedure. And I think you have to be able to correct all the pathology, I think, as the presenters have said. Thank you.

distal procedures

tibial-tubercle osteotomy

chondral defects

osteoarthritis

patellofemoral surgeons