165. Patellar Dislocations & MPFL Management

In this episode of PT Snacks Podcast, host Kasey dives deep into patellar dislocation and the medial patellofemoral ligament (MPFL). Learn about the anatomy, common causes, and risk factors of patellar dislocations, alongside assessment techniques and treatment options. Whether you're a physical therapist or PT student, this episode offers valuable insights into managing both non-operative and post-operative care for patients. Kasey also discusses patient readiness for returning to sports, highlighting the importance of both physiological and psychological factors. Tune in and expand your knowledge on handling one of the most common knee injuries.

00:00 Welcome to PT Snacks Podcast

00:14 Introduction to MPFL and Patellar Dislocation

01:18 Understanding the Medial Patellofemoral Ligament (MPFL)

03:02 Risk Factors for Patellar Dislocation

05:37 Assessment of Patellar Dislocation

07:31 Treatment Approaches for Patellar Dislocation

09:01 Rehabilitation and Return to Sport

12:15 Summary and Additional Resources

13:12 Closing Remarks and Announcements

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Transcript

Hey guys, welcome to PT Snacks podcast. This is Kasey, your host, and if you are tuning in for the very first time, what you need to know is that this podcast has meant for physical therapists and physical therapist students who are looking to grow your fundamentals in by sci segments of time. Now, today we are gonna be talking about the MPFL and Patel are dislocation. But before we do that, if you've listened to the show for at least three episodes and you found it to be really helpful, if you wouldn't mind leaving a review wherever you've been listening, that would mean the world to me. Uh, 'cause those really do make a big difference in terms of helping the show grow. But beyond that, we're gonna review why this matters, which I think. Most of us can surmise that we don't want people to dislocate their patella. Um, but also what is the MPFL? What causes patella dislocations? Who gets this? How do we assess for it? And then what do we do about treatment? That's kind of the outline for today. So without further ado, let's just hop right into it. Um, now with these patients, we can see this. Non-op, post-op. Um, we are very central to helping them get back to what they wanna be able to do and try and do it in a way where we're not causing recurrent dislocations, lateral patella dislocations. It's mostly what I'm talking about in today's episode 'cause that's the most common, um, nearly, almost always injures the MPFL, which stands for the medial patellafemoral ligament. Most patellar dislocations are lateral and in occur in early knee flexion. So when I say early, I'm talking about like the first 20 to 30 degrees during twisting and valgus movement with the foot planted and the quad contracting. So when we're talking about the medial patellafemoral ligament, this is a ligament that is medial. It's kind of named where it is, right? So it's it's medial tooth patella, and it helps basically keep the patella from sliding laterally. If the patella dislocates laterally to the degree where that is no longer restraining at the MPFL, well, it's probably injured in the process. So the MPFL actually in early flexion helps to restrain 50 to 80%. More than that, the patella itself is gonna have a little bit more joint stability naturally to guard against that dislocation. But MPFL rupture and associated choral damage is present in over 90% of first time dislocations. So something we definitely wanna keep into account with people who are experiencing these. When this happens, we see an increase in recurrent instability in 20 to 60% after the first time dislocation non-op, which is a, a very large percentage span. Um, and then we can also see a lot of early cartilage damage and later patella oral osteoarthritis, especially in our younger patients who have this unfortunately. So who gets this? This is the clinical picture. I want you to kind of picture in your mind. It's gonna be. More common in female adolescents, um, who have a family history. They might have trochlear dysplasia, meaning they have a more shallow or flat groove. Um, they might have patella alta where it sits above the groove, a little longer inflection, so there's more of an unsafe zone with that early knee flexion that, the MPFL is mainly restraining . So it's more opportunities for them to dislocate. They can have an increased TTTG distance, which is basically it stands for the tibial tubercle tr groove distance. Now you know why they did the acronym? Um, but it's an imaging measurement that they'll do on a CT or an MRI that quantifies how far laterally the tibial tubercle, and therefore the patella tendon sits relative to the deepest point of the femoral trochlea groove. So it basically measures the lateral pole on the patella that there's more of a lateral pool, increased distance. It's already a little bit easier for the kneecap to dislocate laterally. MPFL insufficiency, if someone is generally lax, that's also a risk factor. And then also you can see this in more of a taller, heavier young male too. So essentially we're looking at genetic components that bias a patient to more easily dislocate. Laterally, whether it's because the joint itself doesn't have as much protection to keep it from going laterally, or there's more laxity, things of that nature. So those are our bigger risk factors. Now, acute lateral dislocations can happen about 50 patients out of every a hundred thousand, and the peak is gonna be in females between 10 to 17 years old. Uh, usually in sports where there's a lot of valgus and external rotation with the foot planted or there could be a direct blow that dislocates the kneecap. So the positions we'll see a lot of times where it dislocates is when, there's early knee flexion and. We're talking about the first 20 to 30 degrees of knee flexion. That person has their foot planted while they're twisting or, or have a valgus moment, and their quad is contracting. That's the most common mechanism of when we see a lateral patella dislocation. So how do we assess? A lot of times that patient, it is pretty obvious when it happens, but they'll have a lateral displacement with either a spontaneous or an assisted reduction, meaning the patella might sit laterally, and then as someone's trying to kind of help them, it pops back into place. They'll have immediate, he arthrosis and an inability to continue activity, meaning pretty painful. They're probably not gonna be going back to sport. Um, the mechanism of injury, as I mentioned before, is gonna be like a twisting valgus rotation near that 20 to 30 degree knee flexion. Imaging findings. Um, generally they'll see an MPFL rupture in like 95 to a hundred percent of acute dislocations on an MRI and chondral damage in about 80 to 85%, whether it's on the patella or the trochlea and loose bodies in 10 to 35%. So something to keep in mind, especially if your patient's struggling and it seems like more stuff is going on, maybe more stuff is going on in your exam. You might see. If it's pretty early on, swelling effusion, pretty limited range of motion. , You can look at their patellar position. Yes, there is lateral glide and apprehension tests. Um, or they can have persistent lateral translation, which would suggest MPFL or medial complex deficiency. Uh, but some red flags to keep in mind would be their knee is locking. There's a large effusion, you're suspecting a loose body or an osteochondral fracture. Also something to keep in mind is if they have repeated dislocations or major anatomic risk factors, like what I mentioned before. , That's also something we wanna keep a close eye on. So that's the MPFL. Hope everybody's doing okay so far. But basically how we treat that, um, or at least a lot of what randomized controlled trials and meta-analyses will do for different situations is depends on is it that patient's first time, was it acute, is it recurrent? So let's go through some scenarios and obviously. , This depends on the patient. What I'm talking about is just general. So this is not medical advice, right? So a lot of times in someone's first time, it's an acute, uh, patella dislocation. They'll probably start out conservative. Now they've also done some studies in. People, skeletally immature patients who it's their first time, there was a randomized control trial where they compared repair versus conservative, and there was a similar return to function. So something keep in mind, again, that's one RCT. The first time in a mature patient with trauma, the meta-analysis actually showed better outcomes with the MPFL repair. And then someone with recurrent. Dislocations without bony dysplasia. And isolated MPFL reconstruction tended to be better. Now. Last scenario, recurrent, , dislocation with significant trochlear dysplasia patella alta, a large TTTG , , distance, MPFL reconstruction plus bony realignment and trop plasty was typically recommended. So, but generally across the board in someone's early phase, that patient who they've dislocated their kneecap, we're trying to protect, , where those. Structures are irritated. There's already a lot of stress happening, so we're not trying to add a ton of crazy more stress regardless of how quick that patient wants to go back to sport. We need to bring that down to reasonable level and create a healing environment. We need to control pain. We need to avoid excessive lateral patella stress, so probably not a lot of. Knee flexion with valgus. Um, working on things like patella mobility, minel superior, working on quad activation, hip abductors, extensors, core strength. , That's more of what you might see in this stage. Then the goal, once we've got pain under control and we're starting to get some good activation, is we're progressing that patient towards normal walking. , Maybe we're doing closed chain strength and like zero to 45 degrees, and then 45 to 90 degrees, , working on. Balance, perturbations movement, quality, that kind of stuff. And then eventually working towards, full range of motion, , trying to get that quad stronger, looking at a quad strength symmetry of ideally 90% of the other side. In our later stages, hopefully we are working on more strengthening, more return to sport activities, more with understanding what the tissue is ready for. And then progressing them later and later to things that they actually need to be able to do for their day to day and utilizing tests to make sure that we are actually accomplishing what we need to. So some examples are quad strength symmetry, where they like 90% within each other, and there no particular order. Their anterior y balance, step down tests, , how do those look? Single leg hop test, lateral even catches. Another example I've seen in research, a depth jump things like that to see. Are they, um, physiologically ready and then psychological readiness. So there's a lot of, RSI scales specifically for the patellafemoral joint. There's the P-F-I-R-S-I and P-F-L-R-S-I for patellafemoral specific RSI scales, , and sports specific drills. So see, is your patient psychologically ready? Um, to go back? 'cause fear can be pretty prevalent. And then just consider that while the patient in front of you may feel pressure to get back to sport or just really may wanna go, , a lot of. , The recurrent dose dislocators with only rehab, , they had a sixfold higher risk of persistent instability than MPFL reconstruction with rehab. , And so in terms of the patients that you're seeing doing their history, are they post-op or non-op? And then, um, in terms of a lot of these return to sport tests. On average, most patients were pretty poor at six months, so it may be more of a long-term battle, realistically, to actually get to the point where they're meeting those metrics that we'd want them to. So in summary, essentially what you should have gone from today is patella dislocations in the MPFL. What is the MPFL? When is it most needed and when does it fail? What are risk factors that could. To predispose somebody to this. And then what do we do about it? If they're, whether they're non-op, post-op, understanding. If some, yeah. Are they not up? So that way we can make sure that we are progressing people appropriately. Now again, this is just a brief episode. There's a ton of research on that, so I have some show notes in there. But if you have any questions, feel free to reach out at snacks podcast@gmail.com. , If I don't know the answer, I'll find somebody who does. And then if you're looking for more, again, I have a a lot of research in the show notes. There's a plethora of information just for your light, enjoyable reading. Other things too, if you're in need of CCUs, med Bridge is actually offering listeners over a hundred dollars off their year subscription. Um, if you're not familiar with Med Bridge, they're actually a continuing education company that has like thousands of CEU courses, specialty exam, prep webinars, all sorts of information, , where you can, if you're trying to take a deeper dive in a lot of these topics, dive in there. , So if you just use the promo code, pt snacks podcast@gmail.com, you can take advantage of that or you can just go in the show notes. Um, but other than that. Connect with me. Um, I'm starting a YouTube, so subscribe on YouTube, follow along. I've got some exciting things on the way. Follow me on Instagram at PTs Snacks podcast. , Join the newsletter. My goal this year is to really learn how to learn so you can follow along with me on other tips of like, just how to actually do that and hopefully not feel like your inbox is being spammed. So all that information is in the show notes below, and, , yeah, I think I've talked long enough so you guys enjoy the rest of your day and I will see you later.