Thanks, James, Ji, and Craig for having me. I'll be talking about patella-femoral instability options today. My disclosures are here. They're not pertinent. So really, patellar dislocations became front and center back in 2019 when Patrick Mahomes dislocated his patella. And the world saw the injury and also the reduction. And it's like they almost popped that right knee. And really, since then, people have been looking more at it and in our football players. So we know the incidence is between 6 and 30 for 100,000 people. It has a very high occurrence in sports, with 60% of them occurring in sports. And 58% of our patients will have osteochondral injuries associated with their patellar dislocation. And 85% will have an associated MPFL injury. Patience rates are high, 64% in patients with open growth plates and 42% in the skeletally mature patients under the age of 25. Atkin et al. followed 74 patients who were treated non-operatively after one primary patellar dislocation and found that 58% of those patients at six months still had difficulty with squatting, jumping, and cutting. So if you look at this, this is a high incidence of recurrence and pain in our football athletes. Return to play timeline. This is a cross-sectional study that looked at the data from the National High School Sports-Related Injury Surveillance System. And they looked at subluxations and dislocations. They found that patients who had a subluxation had a 73% return to play at three weeks and 11% season-ending injuries. Dislocations, however, only had a 34% return to play at three weeks. And 37% of them had season-ending injuries. So these are real injuries and something to consider in our athletes. The National Electronic Injury Surveillance queried the patellar dislocations that presented to the emergency rooms between 2003 and 2008. And 52% of these occurred during sports, with basketball, soccer, and football being the most common sports. And if you look at this, this was the age range between 15 and 30. These are our patients, our football athletes, who had the highest incidence of patellar dislocations. The NCAA Injury Surveillance data from 2009 to 2014 was analyzed looking at patellofemoral injury rates, the mechanisms, the time lost, as well as the need for surgery. Over 600 patellofemoral injuries occurred across 25 sports. And 26 of them, or 4% of them, required surgery. Football injuries were the most likely to require surgery. And 12% of dislocations required urgent surgery. Subluxations are the highest mean time lost per injury, with 11.42 days, followed by subluxations at 7.12 days. MAP Prevention studied all the players who came through the NFL Combine, over 2,000 players who had knee chondral injuries between 2009 and 2015. 100 of these athletes, or 4% of them, had a chondral injury with no prior surgery. And these patients had very high injuries in the patellofemoral joint, in the trochlea and the patella, were the most common areas affected. And what he found was that the players who had these chondral injuries were picked later in the draft, played, and started in fewer games during the initial two NFL seasons. So knee chondral injuries are very common and significant, obviously, in our players. And these are often associated with patellofemoral instability. So who's most at risk? When we look at, so Jason co-presented this back at ISACAS in 2021. He studied the patellar dislocations in the NFL from 2000 to 2012. There were 54 patellofemoral instability episodes. Two-thirds were subluxations, and one-third were dislocations. 19% of the patients required acute surgery. And the mean return to play in the non-operative group was under six weeks. So who and when? When did these occur, and who did they occur in? Mostly in linemen engaged in blocking during passing drills. So physical exam's important. You know, on these acute injuries, we want to look for everything. But on the chronic ones, it's really important to look at alignment, standing alignment, femoral anteversion, external tibial torsion. We want to look at muscle atrophy, crepitation. Again, on the acute injuries, I always use the patellar exam as my guide, looking at the tilt, the patellar glide, apprehension, and full extension, as well as 30 degrees in knee flexion, and how significant is the injury on exam. Radiographs are key. We've gotten on every single athlete who has sustained a patellar femoral injury. We should get these flexion weight-bearing views to look at overall joint space narrowing. You should get a merchant view, not a sunrise view. The merchant view is done in less flexion, and it's used to assess joint space narrowing, patellar tilt and subluxation, as well as trochlear morphology. And then finally, the standing lateral 30-degree flexion view. And this is used to assess patellar height, tilt, as well as trochlear dysplasia. For assessing patellar height, I like to use this Canton-DeChamp ratio as opposed to the in-cell salvati. And I use this because the in-cell salvati ratio is not sensitive to patellar morphology. A lot of our athletes have very short articular cartilage, but have a very long patellar nose. So that'll skew the ratio. Also in-cell salvati ratio does not change with a tibial tubercle transfer. So if you distalize a tibial tubercle, the IS ratio is going to be the same, but the CD ratio will show that decrease. Trochlear dysplasia, as I said, there are three things we have to look for. We have to look for that crossing sign, that supertrochlear spur. And then you can also look for the medial facet flattening on the trochlea. So you can see this on the lateral x-ray. You can see it on MRI, as well as CT scan. And then you can classify it into type A, B, C, and D trochlear dysplasia. The MRI is really the key. This is a gold standard. I don't get a lot of CT scans, really, except for on the chronic instability, because CT scans have a lot of radiation in our young athletes. But on this MRI, we can assess for everything. We can look at the NPFL, the articular cartilage. We can assess patellar height, trochlear dysplasia, measure the tibial tubercle trochlear groove distance, and look for associated pathology. We look at the risk factors for recurrence. There are a lot of risk factors, and these are all found in the literature. So what are the most important risk factors when we look at this? These top four, trochlear dysplasia, patella alta, skeletal immaturity, and history of contralateral dislocation. These are the four most important ones. So in this study, this is a study out of Mayo Clinic in 2013. It was a case control study of over 2,000 patients under the age of 18 with a primary patellar dislocation. And what they found was that trochlear dysplasia and skeletal immaturity had almost a 70% risk of recurrence versus 38% risk in the patients who did not have these risk factors. A similar type study was done in Cincinnati Children's, and it was a retrospective review of 250 patients under the age of 18 after a primary dislocation. These were the risk factors identified, again, a young age, history of contralateral dislocation, trochlear dysplasia, skeletal immaturity, and the CD ratio of 1.45 or a patella alta. But again, same thing. The most significant findings were skeletal immaturity and trochlear dysplasia. And then based on this data, they came up with this prediction model. And this prediction model, you take these risk factors and you plug them in, and you can tell someone what their risk factor is. So an athlete comes to you and they have, let's say they're young and they have some mild trochlear dysplasia. So they have two risk factors. They have a 53% recurrence rate. And so you can educate and counsel your patients. And then he also developed the patellar instability severity score following that study using the same risk factors and giving a point system for it. And the odds for recurrence was five times higher when the total score was over four points. And then finally, the RIF score, or the recurrent instability patellar score, was developed a year later. And they did the same thing using the same risk factors. And then they also looked at the survivalship over 10 years, and they found that the dislocation rate did not decrease over time. It actually increased. So it continued to increase. It wasn't that at 10 years out from your dislocation, you had a lower chance. You continued to have a high chance of recurrent instability with these risk factors. Now we talk about primaries. So fixing a primary instability, you know, somebody dislocates their patella. Is it best to treat them nonoperatively if they have low risk factors, or to fix them? And in these systematic reviews, there are a lot out there, but the most recent ones are from 2017 and 2020. And what they did was they compared the surgical outcomes versus the nonsurgical outcomes for primary dislocators. And they found that there was lower dislocation rates when surgery was done early, but they had similar patient-reported outcomes. But the surgeries were very variable. They had MPFL repairs, they had imbrications, they had MPFL reconstructions. So the data is not really that helpful. But this randomized control trial is helpful. This was published in AGSM 2012, and there were 41 knees. And these patients were randomized to reconstruction and nonoperative treatment following a primary repair. Sorry, a primary reconstruction. And they found that the patients who underwent surgery had a 75% good and excellent result and 0% recurrence. And the patients who underwent nonoperative treatment had a 25% good and excellent result and a 35% recurrence rate. So again, this makes you think, is it better to move towards surgery earlier as opposed to waiting for that second dislocation? We know the risk of recurrence. The issues with recurrence are significant and severe. Chondral injuries, associated loose bodies, the increased risk of recurrence. And the thing that I actually see in my practice a lot is the progressive trochlear dysplasia. You can see on the x-ray below, that was actually a study from a rabbit study. But this is not uncommon. When a kid dislocates their patella, let's say playing football when they're 11 or 12 years old, and they still have open growth plates and they have recurrent instability, that trochlea will never form. And you'll see them when they're 16 or 17, and now they have significant trochlear dysplasia and this recurrent instability and likely chondral injuries. So it's important when you're treating these young patients to get their patella reduced and get them fixed. So non-operative options are certainly a good option in our patients who have low risk factors. We should start that way. And so we know immobilization and extension can reduce recurrent instability, but it can lead to stiffness and weakness. So how long do you immobilize them for? And how long do you brace and tape them for? We know closed chain exercises can promote simultaneous activation of the vastus lateralis and vastus medialis. We know that hip and gluteal strengthening controls femoral internal rotation and chronic patellar instability. And patellar taping can increase quadriceps torque and activates the VMO earlier than the vastus lateralis when it's ascending and descending stairs. So when is early surgery recommended? If you look in the literature, really the only consensus is that when there's an associated loose body. When there's a large loose body and it's causing instability, pain, mechanical symptoms, that's a time to operate early. But the rest of it's pretty controversial. But how about this player? This is a player that I treated probably six years ago. He's a first-round offensive tackle with an acute full-thickness MCL and MPFL injury. And he was very apprehensive on exam at that 30 degrees of knee flexion. He had this exam. And so he was fixed early on, and he's been playing since then. An acute repair, not a reconstruction. So who will fail non-operative treatment? We know the risk factors. We went over those risk factors, patella alta, trochlear dysplasia, high tibial tubercle trochlear groove distance. And in particular, cartilage defects can cause failure, too. They can cause increased instability. They can cause pain and mechanical symptoms. This was another athlete of mine. He was a third-round offensive guard with an acute full-thickness MCL injury, as you can see here. He had that chondral shear injury. But he was interested in trying non-operative treatment, really wanted to push for it. We aspirated his knee, treated him with rehab. He actually had very little apprehension, regained his quad strength pretty quickly, but was really unable to return to play after six weeks of aggressive rehab with our athletic trainers and PT. So he underwent an MPFL reconstruction, and he's been playing for the past three years. Our operative options are a variety, depending on what the risk factors are. So MPFL repair, we know, has a higher incidence of recurrence. But it is an option sometimes, especially if there's an acute traumatic femoral-sided MCL or an MPFL injury, like the ones that I showed you. Or when you're repairing an osteochondral fracture, like above, and you want to go ahead and just go through the medial retinaculum and then repair the MPFL on the way out. But MPFL reconstruction has a lower redislocation rate, so we should consider doing that earlier, as opposed to just a repair. The tibial tubercle osteotomy can be added for, again, the tibial for patella alta, for a high tibial tubercle trochlear groove distance, or to offload an articular cartilage defect. For the chronic cases, again, talking about the revision cases that Ashish was showing you, I always consider this, too, in my patients who come with recurrent instability or failed primary surgery before, we look at femoral osteotomy to address valgus alignment and a trochleoplasty for chronic instability, for de jure type B and D, with that super trochlear spur. So key points are to really take this through, examine history. Are there associated injuries? Have they had a prior history of instability? Have they had contralateral instability? Where are they in their career and their season? You have to think about these risk factors. Again, when you're counseling these patients, they have a primary dislocation, but what's their chance for recurrence? Can they finish the season? Should they have it fixed at the end of the season? Should they have it fixed immediately? Again, trochlear dysplasia, skeletal immaturity, patella alta, a high tibial tubercle trochlear groove distance are the most important risk factors, and use of the prediction models that we talked about. This was an athlete, a football player, who you can see had recurrent instability and had this large chondral defect, 15 years old, and I had to replace the whole patella because of this large defect in recurrent instability. So address these early and quickly. Thank you.

patella-femoral instability

patellar dislocations

osteochondral injuries

MPFL injuries

recurrence rates