So, I'll go through this talk and we'll wait for questions at the end to sort of get back on track here. That's an excellent, excellent panel so far. So I've been sort of tasked on talking specifically about the patellofemoral joint. And as a non-arthroplasty surgeon, we'll kind of walk through a little bit why maybe the joint is a little bit different compared to the talk that Dr. Strauss gave. My disclosures can be found on the website. And so the patellofemoral chondral patient is certainly a very challenging joint to treat. And we had to talk about the arthroplasty, but as a non-arthroplasty surgeon, the focus of this is just how can we maybe improve outcomes in that patient by avoiding or delaying arthroplasty as the ultimate goal. And our options are many, right? We have ACI, we have particulate adrenovated cartilage, we have whole tissue transfer. And when and where to use these, I think, is where it kind of comes into that decision-making process. We wrote a review from our group and then Dr. Ashley Gamal wrote a similar paper as sort of comparing these strategies in specifically the patellofemoral joint. We both kind of came to the same conclusion is that there's really not a lot of evidence to support one versus the other. And so I think it really comes down to that individual patient. What are their goals? What is the challenge? And the surgeon's comfort level with these certain techniques. This is something that I think is very important and always impacts our patient shared decision-making is the time for recovery. And so while an ACI may be an awesome solution for the lesion, if the patient's not willing or interested in participating in 9, 12, 16, 18 months of recovery, then maybe that's not the best surgery for them. So for me, this is always a shared decision process here. Whole tissue transfer, we know that both OATs and OCA grafts demonstrate good patient outcomes with high survival rate at over 77% at 10 years. For me, in the patellofemoral joint, I generally reserve the whole tissue transfer on the trochlear side mainly due to the technical challenge in the patella. And I feel I can do a pretty good job of resurfacing or restoring with cell-based seeding therapies that we'll talk about a little bit later. But certainly in a patient like this with bone loss, central trochlea is a great option. What about cell-based therapy? We talked previously about in general the whole all comers patellofemoral medial lateral compartment having excellent results of ACI. This is a specific study coming from Dr. Gamal and Tom Minus looking at a series of patients with quite large patellofemoral lesions. Almost two-thirds of them were type 4 pancentral lesions that had excellent results at 86%. Over two-thirds of them had TTOs. Interestingly, in this study, there really wasn't a correlation of the TTO to outcomes. What about our fourth iteration of the autologous conjugate implantation? Now we're talking about matrix-induced autologous conjugate implantation where we're taking the patient's cells instead of squirting them in as a slurry and hoping that it levels out. Now we're implanting them on a porcine collagen membrane and essentially gluing them into the joint. We're seeing similar results throughout the knee, but particularly in the patellofemoral as well, and has made the ease of application much easier and quicker for the patient. Single-stage, and so certainly there's an option of particulate juvenile L-graft cartilage or P-jack. And so as a single-stage application, it has the advantage of one, it's on the shelf, two, as a single stage. And so one of the disadvantages, though, insurance companies are often reluctant to pay for this even though there is some evidence to support it. This is actually a patient of mine who had episodes of recurrent patellar instability with a new condyle defect that was irreparable, and he, we had originally discussed about ACI but was not interested in a stage surgery, was going back to school, wanted to get it done as soon as possible. So ended up doing a P-jack at the time of his tubular tubercle osteotomy and patellar stabilization, and has done pretty well. Evidence behind this, certainly there's some MRI evidence demonstrating good cartilage fill at long-term endpoints as well as improvements of patient scores, but that really doesn't have quite the rigorous head-to-head stuff as some of the other cartilage restoration techniques. This, I think, is critical, and Dr. Strauss talked about it earlier in his talk, but alignment in the patellar form of joint is just as critical as varus valgus in the knee. And this is a study by Dave Flanagan that showed that the results were improved with concomitant TTOs. I talk about this with the residents as fellows as the analogy of the fish out of water, you can't expect a fish to do well out of water, and nor should you expect a cartilage restoration technique to do well in the poor biomechanical environment that it was in before. So I do have a low threshold of adding TTOs with these, and it comes on some of the basic science data. It's looking back at Fulkerson's original AMZ biomechanically, the ability to offload the lateral and distal aspect of the patella but add sacrifice to the medial side, and so we'll talk a little bit later about how you can adjust your cut in order to accommodate for your lesion. This is a patient of mine, so as a case example, this is a 22-year-old female nurse. She had a previous history of, unfortunately, a radiofrequency chondroblasty by another surgeon, and it came to me, really at that point, with an inability to work because of her anterior knee pain, swelling, and recurrent mechanical symptoms. This is her original MRI with a large lateral facet, full thickness defect, and that incredible amount of reactive edema in the lateral facet due to her malalignment. Her TT to TG was about 18. This is, so we talked about it, and I'm a big fan of diagnostic scope, just like Eric said, and so we talked originally about a diagnostic scope. Let's see what we're dealing with here. These are the scope pictures, so a large grade 4 defect on the lateral patella, and something that we didn't necessarily see on the MRI, which is a kissing lesion in the superior medial trochlea there, and so we biopsied for ACI and eventually implanted her. These are her pictures at the time of implant with a 60-degree cut, and so I wanted to be careful not to overload that medial side, but felt it very important to offload this joint and get her tracking more centrally. This is her post-op MRI at about 9, 10 months, demonstrated a good fill of that lesion and resolution of that edema, which I think was probably most critically affected by that TTO. She's doing great. She's back to work in an ICU and running again, actually. So how to cut your TTO? If you want to look at the nitty-gritty of math, it really can be calculated by the inverse tangent of the desired anterior divided by the medial movement, but if you think about it as an isosceles triangle, at a 45-degree cut, you're moving one to one. As you increase the slope of that, you're going to anteriorize more than medialize, and so for someone who maybe has a borderline TT to TG, but not so borderline that you're worried that you're going to too far medialize, you can do a 60-degree cut to anteriorize. Rarely, but it has come up, and I'll show you a case at the end in a patient who has a completely stone-cold normal TT to TG. There is a potential opportunities to anteriorize, and this is a technique that's been out there and has been proven to decrease the contact pressures in the patellofemoral joint, and maybe potentially avoid some of the old complications of the traditional McKay, where you did a direct anteriorization, but has an opportunity of directing it directly anterior. This is a patient example here. So this is a 36-year-old female patient of mine, had a previous history of a chondroplasty lateral release for patellofemoral pain, referred to me for recurrent pain, swelling, difficulty working. She had failed extensive non-operative treatment. At that point, we include multiple NSAIDs, injections, viscosupplication, PT. Her radiographs look good. This is her initial MRI, which did demonstrate this sort of central pan-patellar grade 4 defect with what appeared to be a pretty good-looking trochlea. Her TT to TG was 10, and I'm being generous there. It was really probably 9. And so we talked again about a diagnostic scope assessing the situation, and this is what we saw interoperatively. So large central patella defect. Trochlea was relatively intact, aside for some early blistering that we could probe was stable. There wasn't undermining or delamination, but debrided quite a bit, or a little bit to get it smooth, but did not feel that that ultimately would require treatment. We biopsied her at the time, and then returned to do her Macy implants, and did, in her case, a direct anteriorizing osteotomy using that technique. Now we can talk about the pluses and minuses of that and that, but she's at this point doing pretty well. What about, so this is also the potential for arthritis. What about AMZ alone without cartilage restoration? And so this is looking back at Piergino's and Fulkerson's original study back in 1997, looking at his AMZ technique for patella chondral lesions. And what he found was that there was 86 or 87% good to excellent results when you had type 1 and 2 lesions, which were distal, or excuse me, type 1 and 3 lesion, 2, distal and lateral lesions. He's followed this up recently with a minimum follow-up of 15 years, some over almost 20 years. And in that series, there's a 94% patient satisfaction with no conversion to arthroplasty. Interestingly, and we'll talk about it briefly, and I'm sure Dr. Gamal can talk about it, the hardware removal is very, very high in these patients. The screw tips eventually make it subcutaneously, and a lot of people want them out. So if you counsel them beforehand, that doesn't come to much of a shock. But in my opinion, if you can get someone who's in their 20s and 30s 10 to 15 years out of a TTL before they consider the potential for arthroplasty, and they've been able to maintain their active lifestyle, I think that's a great win. Here's a patient of mine, last example, and then we'll turn it over so I can stay on time here. This is a 42-year-old female, actually was a family friend of ours. She dislocated her kneecap as a child, had a loose body removal, arthroscopy, and had did well, very well over her adult life without any instability, but came to me just with recurrent anterior knee pain again, effusions. Her exam demonstrated no instability aside from a mild J sign. This was her initial radiographs, which looked pretty good. She didn't really have any overt signs of degeneration on her radiographs. Her MRI demonstrated pretty much diffuse, what in my opinion looks more of a degenerative type process in the distal and lateral half of her patella, with some lateral maltracking. Her TT to TG was roughly 17. So for her, we talked about first the potential for any type of cartilage restoration, which would be dependent on her diagnostic scope, and then more importantly, I think for her, an offloading osteotomy. Ultimately, when we got in here, this is what we found. Really more of a degenerative type process. Her trochlea was pristine, although dysplastic, but pristine, with distal and lateral lesions. We debrided. I did biopsy on her at the time because one could make an argument for ACI if she didn't do well, but we did an osteotomy, and she's four years out now, and she's doing great. And so I think this is hopefully going to help her get into later in life, where eventually if she develops arthritis, then osteotomy is not that big of a problem, or excuse me, arthroplasty. Some complications. I'll skim over this a little bit, but relatively safe. The highest complication probably is hardware removal with those screw tips being prominent, and it's more common when you use the 4-5 screws over the 3-5, and then the risk of nonunion and delayed union when you detach completely that cortical hinge and distalize. So key points for me is the patellofemoral chondral disease is really a spectrum of disease, and advanced treatments really require very careful workup and evaluation of your patient and their goals. And again, patellofemoral lesions can benefit from a variety of cartilage restoration techniques, and the offloading, the powerful offloading effect of a tubercle osteotomy should be considered and potentially impacting their ultimate outcomes. And then in select patients, for me, distal lateral lesions can do pretty well with an AMZ. Okay. In the interest of time, we'll wait for questions until after Dr. DeMalle goes. Thank you.

treatment options

patellofemoral chondral disease

improve outcomes

avoid or delay arthroplasty

individualizing treatment