All right, our next speaker is Jonathan Brauchman from Colorado University, and he'll be speaking on the patella-femoral. Jonathan? Thanks, Chris. Welcome back, everyone. Hopefully everyone's fueled up by their Chicago dogs here, ready to go through some of this. So just a bit of note. Things that are in either yellow or red are things that have been either on exams or in questions, so pay attention to those. I will say they didn't reproduce quite as well. They're in like a faint gray in your handout, so some of those things you may want to write in. I've also added about another 20 or 30 questions at the end of the talk. Yes? Page number 543, and all those, the extra questions that I've added since the booklet was published will be available to you guys after the course. So my disclosures, patella-femoral will go through anatomy, biomechanics, some physical exam pearls, and imaging. Most of this, I think, especially for patella-femoral and meniscus will be largely review here, but I'll point out the things that I think are important. This is the spectrum of what we're going to cover, and some of these things are really just some rote memorization. So the soft tissue restraints, both active and passive, of the patella are active at zero to 30 degrees. The articular congruity of the patella and trochlea are more important beyond 30 degrees, so particularly the lateral facet or in things, situations like trochlea dysplasia, this is going to play a bigger role. The static or passive restraints here are the MPFL, the meniscus patella-meniscus ligament, the medial retinaculum, and the vastus medialis, so this also can be a dynamic stabilizer. You have to know the layers of the knee, and the first layer is deep fashion sartorius. The layer two is what they typically like to hone in on. This has superficial MCL and the MPFL within it. This is good exam question fodder. And then layer three is the capsule and or the deep MCL. Those are really interchangeable soft tissue. The MPFL itself resists about 60% of the lateral translation force, and this resists subluxation, a greatest close to extension. So like we were talking about, less than 30 degrees is when you're going to see that. As far as the extensor mechanism, the patellar tendon, there have been some questions about some of the average measurements here, and so the length is about 4.5 centimeters, the width 2 to 3.5 centimeters. The quadricep tendon is about two times the patellar tendon thickness. Again, kind of an inane fact, but this has shown up on some question banks. The VMO, as far as the extensor mechanism, attaches at a 55 to 70 degree Pennate angle. That's also been examined. And the trochlea, the depth is approximately 8 millimeters in a normal situation. The lateral facet is higher. That's always going to help orient you when you're looking at an axial image if you can't see the fibula. And this has the largest cartilage, thickest cartilage in the body, up to about 5 millimeters in a normal situation. The patella itself increases the moment arm for extension of the musculature. The terminal 15 degrees of active knee extension is when this is most important. The inferior third is devoid of cartilage, non-articular. So if you see a fracture there and you're asked if that involves the articular service, that's typically not the case. The extra osseous arterial anastomotic ring is important. This is supplied by the geniculate arteries. And the functional blood supply is from distal to proximal. They may show you a picture here, which I've seen, and they'll try to fool you on knowing where and which geniculate artery leads to either patella or ACL blood supply, which is something to simply look at this diagram in a little bit more detail. The contact area where the patella engages at the trochlea groove, about 20 degrees in the arc of flexion, the quadricep tendon will then contact the femur and the patella and is generally out of the groove beyond and at 90 degrees. The patellar contact move proximal and the surface area increases with knee flexion and patellofemoral pressure is highest between 60 to 90 degrees. As far as joint reaction force, this has also been on several exam questions. About half of body weight is happening with level walking, over three times body weight with stair climbing, a 90 degree isometric contraction produces over six times body weight and seven to eight times body weight with a loaded squat. A quick question here, which of the following statements concerning biomechanics of the extensor is true? I'm going to skip through these kind of quickly. These are all within your handout, spend some time going through them. But it's that the patella increases the lever arm of the quadricep. What is the primary restraint against lateral patellar displacement? And we have superficial medial retinaculum, the patella tibial ligament, patella meniscal, patellofemoral and vastus and that's going to be the MPFL. In the normal knee, the patella becomes centralized where, again, that 15 to 20 degrees it's going to engage into the trochlea. And the central quadricep tendon is half as thick, same thickness, twice as thick, much shorter, not a viable option and it's that it's twice as thick as patellar tendon. As far as physical exam goes, always important to understand the standing and walking exam as far as limb alignment, presence or absence of rickervotum, atrophy, foot mechanics, pronation, hindfoot valgus, patellar tracking and generalized joint laxity where you may see a question related to something like the Baton score in regards to generalized joint hyperlaxity and differentiating that from patholaxity. It's important to look for the J sign or they may put that into the exam stem of the question. What this is is lateral translation in extension. Crepitation is going to be a sign of patellofemoral crepitus or cartilage disease and early arthritic changes and extension lag which is going to be the buzzwords for patellar or quadricep dysfunction or tear and or something like a transverse patella fracture, extensor mechanism disruption. In the supine position, you may see a question related to examination of the hip and looking for something like a log roll or they'll point that out to you. Remember that the obturator nerve innervates both the hip and the knee. IT band tightness, we can look at that with Ober's test, the patient on the side allowing their passive adduction of that leg is what they're going to lead you towards something like looking for IT band tightness or IT band stretching with physical therapy. Effusion, hemarthrosis, tenderness and stability and for stability with the knee in extension, what we're looking for really is passive lateral translation and we're grading that in regards to quadrants. So anything greater than or equal to three quadrants is going to be abnormal. It's going to be pathologic lateral translation with the knee in full extension. What about patellar tilt? And it seems that more questions are gearing towards differentiating who needs and who does not need a lateral release. I think it's really sort of fallen out of favor and that seems to be a hot topic that a lot of questions are showing up about. They'll give you a patient where they're trying to tell you has excessive lateral pressure syndrome, fixed lateral tilt, a tight lateral retinaculum and some mild chondrosis in regards to trying to indicate that patient for an isolated lateral release. So remember that abnormal here is going to be less than zero to five degrees of passive tilt. As far as radiographs go, we all I think are well aware of our standard radiographs. There's really nothing special that they'll ask you there. You may want to be aware of some average patellar height ratios and patellar tendon length. There is indeed a negative correlation between patellar tendon length and MPFL width and this is important because the MPFL width, if it's narrow, especially in the setting of patella alta, has been shown to be an increased risk of lateral patellar instability. So they may set you up with a question like that. You can really, I think, pick your patellar height measurement of choice, Katanda-Shomps or Blockburn-Peele, looking at what is normal and generally less than .8 is going to be considered Baja depending upon which of these you look at, either 1 or 1.2 is going to be considered alta. And generally they will not make it subtle, it will be obvious where they're not expecting to make the measurements and do the math. The shape of the trochlein position is going to be somewhat important here, specifically in the setting of fixed lateral tilt or lateral subluxation. Be aware of the bradella patella, this is with the arrow here showing that very small avulsed fleck. That's the attachment on the patellar side of the MPFL that's been pulled off in a chronic patellar lateral instability situation and there's ossification of the patellar attachment of the MPFL and this is correlated very specifically with the episode of lateral patellar instability and chronic MPFL tear. What about MRI? So the signs here that we're looking for, hemarthrosis, fixed lateral patellar subluxation, contusion or that kissing bone bruise on both the patella and the lateral aspect of the lateral femoral condyle, frank osteochondral fracture, MPFL tear and other internal derangement and I put the other internal derangement on there because some of these they'll try to lead you down the pathway of a patellar instability situation but it's really something simple like an ACL that they're really trying to trick you and just pull out that you know the difference is between this bone bruise pattern and standard say pivot shift bone bruise pattern and there's a question coming up. So you see here on this, you see a small loose body, you see the characteristic bone bruise, this is another situation looking at an acute osteochondral fracture so these are what they're expecting you to look at and that's the donor site. The congruence or patellar tilt is something to look at, I don't think they're going to make you make these measurements or get too sticky as far as the congruence angles go though TTTG is certainly fair game and 20 millimeters is going to be about the cutoff here, I don't think that they'll give you a borderline situation, I think they'll make it quite obvious and this is the tibial tubercle to trochlear groove distance measured as you see here where that line is propagated across the posterior aspect of the condyle through the center of the base of the trochlear groove and then the distance to the center of the tibial tubercle is measured and this is a sign of rotational alignment or essentially really rotational malalignment of the patellofemoral joint. So putting this to a question, a 12-year-old football player two weeks earlier, sudden onset of pain, right knee while blocking an opposing player, unable to continue but was able to walk, x-rays are normal, treated with two weeks of anti-inflammatory, localizes the pain medial and anterior of his knee, physical exam, they show full passive active motion, no effusion, ligaments are stable, gait is antalgic with a limp and pain is reproduced with log roll of the right lower extremity. So they're heading you I think down a pathway of a knee problem here, what's the next most appropriate diagnostic test and it turns out that this is AP radiograph of the pelvis and lateral radiograph of the hip and this is a skiffy in this young player. So they'll try to deceive you a little bit. Changing gears a little bit to patellofemoral pain syndrome, understand that the predisposing factors here are going to be things like hip abductor weakness, a shortened quadriceps muscle, abnormal VMO reflex time, hypermobile patella, they might give you a clue to something like that with a Bayton score, general hyperlaxity, chondral lesions of the patella and trochlea and it's important again to evaluate that entirety of the lower extremity. The mainstay here and the key is going to be non-operative management, this is going to be therapy, bracing or taping, orthotics, NSAIDs for short-term pain relief and really unfortunately no conferred benefit from steroid or visco supplementation in these patients. Operative treatment may certainly be reasonable in selected patients that have failed non-op and very importantly they'll show you either an MRI or they'll tell you that they have a symptomatic loose body with frank mechanical symptoms or they have a chondral flap. In that setting I think the answer is very reasonable for arthroscopic debridement but I think that they're really going to look for you to treat these patients non-operatively unless they give you that exact setup with a chondral flap or a frank loose body that you see very clearly on MRI. What about malalignment? So again back to a bit of tilt and subluxation, you have to know those risks factors, we exhaust non-operative measures, physical therapy strengthening and they may ask you to do something with core and hip and hip abductor strengthening in particular, orthotics, bracing when appropriate and anti-inflammatories. These are the predisposing factors and they'll often throw some of these in and these factors are genu-valgum, static recurvatum, increased femoral anteversion, internal femoral torsion, external tibial torsion and patellar trochlea dysplasia and these are going to predispose these patients to malalignment. Continued here with ALTA, VMO atrophy, tight lateral restraints, so they're going to tell you that they have a positive oversign for that, a lateral tibial tubercle or with an elevated TTTG, pes planus or hyperpronation and again generalized ligamentous laxity or high Baton score. In this setting and I have seen several questions related to this, isolated lateral release may indeed still be appropriate but only in the setting of excessive lateral patellar facet syndrome with a fixed tilt and tight lateral retinaculum, tilt without subluxation and mild lateral facet chondrosis. The key here if they ask you is to maintain the lateralis fibers, you don't want to get into the quadricep. The risks are things like hemarthrosis, CRPS, chronic quad weakness and production of medial patellar instability. I think the pendulum is swinging away from lateral release for everyone with patellar pain and they're going to try to hone in on asking a question about that if you do come across one. Causative factors associated with patellar femoral symptoms include which of the following, just like we went through, external tibial torsion. The others are the opposite of what would cause patellar instability or lateral excessive pressure syndrome. Which of the following preoperative factors is conducive to achieving the most consistent and predictable results when performing isolated lateral retinacular release of the knee? This one's going to be passive lateral tilt less than five degrees. So they're showing you they've got fixed lateral tilt here, tight, fixed lateral retinaculum. Iatrogenic medial patella subluxation is best corrected by which of the following? And this is gonna be reconstruction of a lateral patellofemoral ligament or closure of the previous lateral release. Patellofemoral malalignment continued here, talking a bit about tibial tubercle transfer in the setting of a lateral quadricep vector. So this is in that patient that they're gonna set you up with some maybe valgus knee, high TTTG greater than 20. They're gonna be looking for you to add a tibial tubercle transfer in those patients. Remember that the straight medialization is the Elmslie-Trelat. I don't think that they're gonna probably drill down to this so specifically. And this is more appropriate in the setting of no arthrosis. If you're trying to unload a early DJD or a patient that has some mild chondrosis, the Fulkerson osteotomy or standard antramedialization is gonna be a better answer if they give you those options. Remember the McKay is also an anteriorizing osteotomy that is most likely not gonna be the answer on any of these because of problems with skin necrosis. That's probably not gonna be the right answer in most of these questions. The antramedial transfer, why it's important, the Fulkerson osteotomy is that it unloads the distal and lateral patella. They will ask you this and they'll ask you where it best unloads chondrosis. So if you have chondrosis in other areas, Pedoriano and Fulkerson wrote an article about this and it seems to be highly tested that they will offload and have better success if it's distal and lateral in those locations. Lengthens the quadricep lever arm, increases the patellar contact area and decreases stress per unit area, basically like rotating the tires. The optimal displacement of the osteotomy is about one centimeters of anteriorization and medialization of about half to one centimeter. So the antramedial tibial tubercle transfer best unloads which of the following damaged patellar articular surfaces? Again, distal and lateral. What about lateral patellar compression syndrome? So in the setting again of tight lateral retinaculum, excessive patellar tilt and resultant chondrosis. These patients present pain up and down stairs, the movie theater sign. Their exam is gonna show pain with patellar compression, lateral facet tenderness. They're gonna have fixed lateral tilt and the inability to evert the lateral edge. That's gonna be something like in the question stem of less than five degrees of lateral tilt. Their first line treatment is gonna be non-operative as we're well versed in. And if they ask you again like that previous question about operative treatment, lateral release. And then beware of heading down a pathway for patellar realignment. So again, the MacKay, beware of skin necrosis or wound problems, a straight medialization or an antramedialization. And they'll set that up based on the question stem as you saw in that previous one about if they're heading you down a pathway of just instability or chondrosis or otherwise. What about IT band syndrome? So this is typically caused by contact between the IT band and the lateral femoral condyle, often referred to as runner's knee. Physical exam shows localized tenderness over the lateral knee over the IT band bursa, worse with the knee at 30 degrees. They're gonna have typically a positive OBER test. Again, traditional non-operative treatment, steroids, iontophoresis. Rehab is most often successful. However, if they do require operative treatment, surgical excision of the posterior IT band and IT band bursectomy is what you want to perform in these refractory cases. I think they'll set that up very clearly for you in the question stem. What about the acute lateral patellar dislocation? So often this is gonna be the result of a non-contact twisting injury. The patients are gonna describe that the knee gave out. They often feel a pop. They have quite significant tense swelling. So this may be confused or the question stem confused with something like a tibial plateau fracture and quite diffuse pain. The pathoanatomy, that MPFL that we talked about being so important for patellar stability is going to be torn about 90 to 100% of these cases and it's often at the femoral attachment. And I think this is one of the reasons which this idea may be getting mature enough now of why isolated MPFL repair may not be as successful as previously thought or as previously performed because many of these are mid-substance ruptures or femoral-sided ruptures and so tightening them on the patellar side may not actually be addressing the pathology and you may see something related to that. There's often a medial retinaculum tear, chondral damage, acute osteochondral fracture and osseous contusion. The patella can have a chondral or osteochondral lesion involvement about 95% on the patellar side, the lateral femoral condyle about 30%. And the reason that this is important is that this is gonna be one of the things that they're gonna ask you about as far as an acute indication to operate on a first-time dislocator is in the setting of an acute osteochondral fracture. That's gonna be asking you to be a bit more aggressive in that patient rather than just physical therapy. So acute dislocation of the patella is associated with what percentage of MRI-documented injury to MPFL and it's gonna be greater than 85%. If there's no osteochondral fracture or loose body and no other associated ligamentous injury, then the mainstay here is gonna be non-operative treatment. At least of most first-time dislocators, at least 50% of them will never have another instability episode. And so for sure, non-operative treatment is the standard of care there. And you wanna control their swelling, brief period of immobilization to settle down their swelling, then get their quad working, get their range of motion back. You can certainly work with some lateral buttress bracing. What about if osteochondral fracture or a loose body, underlying predisposing factors in a high-demand athlete? This is gonna be the setup where the question stem is gonna guide you towards being more aggressive in this patient and operating at their index dislocation. So arthroscopy, debridement, loose body removal, or osteochondral fracture reduction and fixation. And the thing that remains, I think, a little bit controversial here that I would be very surprised if you found a question on this test about is what to do with the MPFL, be it repair or MPFL reconstruction or TTO. I think that they're going, that I think in the literature is still a bit controversial. And I think the level five evidence proves that that may be about the only situation where MPFL repair may really be the most well-indicated is in the setting of being there already for osteochondral fracture fixation or, frankly, acute loose body removal. I do think that that's a little bit too controversial, but just be aware, be aware of that. So again, repair, reconstruct, medial retinaculum fixation and VMO treatment if it's torn off with the sleeve of tissue, which they'll ask you about. I'm gonna go through these quickly so you guys can look through these. These are all in the handout. Just to make sure that we're able to cover all of the material. Actually, this is a good one. 16-year-old tennis player, twists her knee, sustains lateral patellar dislocation, requires closed reduction, post-reduction film is shown. So they're looking for you here to identify an acute osteochondral fracture here. And so what would be the most appropriate initial treatment? And so this is asking you to make a decision to go to the OR with her index dislocation. This is also a good one and just an indication of how they may try to trick you in regards to understanding the bone bruise patterns. This is a 15-year-old, twists her knee, ice skating, feels like her kneecap came out and went back in on its own. So they're heading you down this pathway of patellar instability. And she now complains of her knee frequently giving way and an MRI is shown. So they're heading you down this pathway of patellar instability, but clearly this is a pivot shift bone bruise with an ACL tear. So don't be fooled by that. Rely back to the things that you know. And the most appropriate treatment here in this patient is ACL reconstruction. So again, recurrent patellar dislocation, risk of re-dislocation, two to five years is about 50%. Failure of non-operative treatment is gonna be your indication for surgery. Specific surgical procedures really depends on alignment, version, the TTTG, the patella and trochlea morphology, patellar tendon length, and then putting all those things together with your imaging. For excessive genu-valgum or femoral antiversion, the correct answer may indeed be femoral osteotomy, which is virus producing as well as derotational. I think that this has probably fallen out of favor a bit, but I think it's worth knowing about. I think the thing that you're gonna see probably come up most frequently here is a TTTG greater than 20, and they're looking for you to make a decision to do a tibial tubercle osteotomy. Tibial, sorry, tubercle sulcus angle greater than 12 degrees and again, that TTTG greater than 20 are gonna be the numbers. Those are gonna be the buzzwords in the stem that are looking at you to make this decision for TTO. And in the setting of patella alta, you may add a distalization to that procedure. What about MPFL reconstruction? I think there's certainly not reams of data on this, but the early data shows that there's really no difference between allo or autograft. Anatomic tunnels and anchor placement is critical. There are over 100 described techniques, so I don't think that anyone's gonna be asked about technique related things. It's just like the CC ligament reconstruction. When we have 100 different acceptable techniques, it means that none is really clearly superior. And be really careful here to not over tension these. So non-anatomic attachment sites dramatically increase the force and pressure on the patellar cartilage may lead to early chondrosis and cartilage wear. A two times compressive force can be seen with a two proximal femoral attachment, and this abnormally shortens the ligament. This is important, and spend a minute looking at this and looking at this diagram. This is Schottel's point, and that was published in the AJSM 2007. And what this is is about one millimeter anterior and 2.6 proximal to the adductor. And they will absolutely ask you in words where this is, and pay attention a little bit to the relative anatomy. So this is taken from Rob LaPrade's work showing the interrelationship of both the POL, the superficial MCL, the adductor tubercle, and the medial epicondyle to the MPFL. So these are worth taking a look at. There's, I bet, sure to be at least one question on Schottel's point. Tension the graph with the patella engaged in the trochlea, at least some degree of knee flexion. That's controversial, whether that's 30 or 90 degrees, and the goal is to create one to two quadrants of glide and reducing things like tilt. Again, I'm gonna go through these kind of quickly. Plica syndrome, suprapatellar, medial, or infrapatellar. These are found in many normal knees and many asymptomatic knees. I think the pendulum has swung kind of back and forth on this over the years. I wouldn't bite on scoping these unless you prove that they've really failed all non-operative treatment. Arthroscopic excision, if they're persistent and painful. Snapping of a thick and fibrotic band over the medial femoral condyle. They may ask you about the role of a direct injection or an intraarticular injection to help support your decision to take this patient to the operating room. And what about patellar and quadricep tendinopathy? So this is gonna be often in the setting of quadricep and hamstring tightness, recurrent microtrauma such as a jumper, basketball player, volleyball player, and these are diagnosed by local pain, ultrasound, and or MRI. The mainstays here is gonna be non-operative treatment, and if you see the words eccentric strengthening, that is the correct answer. Debris to repair for persistent pain. I would be surprised if they're gonna take you down that pathway. A quick question here, 48-year-old runner, complains of pain behind his kneecap. History significant for patellar tendinitis, which resolved, is currently asymptomatic. View from his knees, got a little bit of insertional distal pole patellar tendinosis here. What would you suggest to decrease his symptoms? And this is in for patellar strap. Stretch and strengthening exercises. They're asking you to continue non-operative treatment here. I'm gonna go through these. Osgood-Schlatter, if this comes up. This is an apophysitis, typically in a younger athletic population. This rarely requires surgery. Your mainstays here are gonna be activity modification, stretching, potential for a show pat strap or a brace. Refractory cases may be amenable to arthroscopic or open excision of the tubercle fragments and repair of any torn or frayed tissue. Here's a 17-year-old basketball player and pole vaulter. Anterior knee pain for 18 months. Inability to jump based on the MRI scan. And they're asking you here to debride and repair. This is 18 months of failed treatment. What about extensor mechanism disruption? So quad tendon rupture. Generally, you're gonna be older. Degenerative tendon proximal to the patellar insertion versus a patellar tendon rupture are typically going to be in a younger patient with typically normal tendon and typically distal to the patellar insertion. Surgical treatment with early end-to-end repair. Some sort of non-absorbable suture. Longitudinal drill holes. You may see a question related to transverse drill holes. I would avoid that. That's a risk for fracture. And or suture anchor. However, there is some recent evidence that shows that suture anchor may be at least as strong and potentially more beneficial than a previous transosseous type repair. Rehab them in a brace with extension lock are the critical buzzwords here that you're gonna look for. What about avulsion, skeletally immature? Adolescent boy is gonna be your primary athlete involved here. This is really an apophyseal fracture. There's not any confirmed relationship with untreated Osgood-Schlatter. Must rule out other injuries here. So things like ACL or involvement with a frank tibial spine avulsion, collateral injuries and patellar tendon in about 10% of these patients. So they may ask you after you do this to do an EUA focused on some of these findings when you do take them to the operating room to fix that. And again, when they're displaced, they need stable internal fixation. There are multiple ways to do that. Extensor mechanism repair. If indeed necessary and these must be monitored overnight for compartment syndrome. So if that's an option in your immediate postoperative care that's gonna be the right answer. Patellar fracture, often the result of a direct blow. They can be in multiple patterns. If they're displaced and that's typically greater than three millimeters, these need to be fixed. Any articular step off of greater than two millimeters. So they may give you some imaging characteristics there for which we're gonna wanna fix those. There are multiple different ways. I don't think they're gonna drill down on the ways to fix these. Partial patelectomy if given as an option is really reserved only for severe comminution and a reattachment of any extraneous or remaining tissue is gonna be critical. Again, I'm gonna buzz through these for the sake of time, which are in your handout. The bipartite patella is important. It's important to recognize. It's an accessory ossification center. It's present in about 3% of the normal population and bilateral in at least half of that population. The most common position is the superior lateral position, which you'll see on a plain AP x-ray. These are typically incidental, often asymptomatic. Non-operative treatment, typically they're going to be presenting for some other reason. If you do get headed into operating on these patients, if they're setting that up for you, excision with lateral release, vastus detachment from the piece with re-repair is going to be the answer. Rarely is RAF of the fragment going to be the correct answer, typically simple excision. What about articular cartilage defect in the patellofemoral joint? So this is obviously a challenging problem. Always begin with thorough non-operative treatment. There's poor clinical evidence that supports any specific surgical technique over another. But things like cartilage restoration in addition to realignment, and I think if they're asking you to do this in a question, what they're looking for is to not only do the cartilage restoration procedure, but address the underlying rotational abnormality. Or they're going to give you a setup where the patient has a full thickness cartilage defect and an underlying 22 millimeter TTTG. So they're asking you to do cartilage restoration and an osteotomy, things like that. That's where I think this is going to be important in a question. What about DJD? So this is underlying associated with maltracking, instability, and genuvalgum. Your mainstay here, again, is going to be non-operative treatment. Arthroscopic debridement with lateral release, a MacKay tibial tubercle elevation may be appropriate, as well as patellofemoral arthroplasty. Patelectomy is most likely not going to be the answer. There's extremely narrow indications for this. Post-traumatic arthritis, comminuted patella fracture. But the expectation would be significant loss of quadricep power, ongoing knee instability, persistent pain, and less than half of the patients will have good to excellent results. And it's irreversible, so please avoid that. That's probably not going to be the right answer on this test. Patellofemoral arthroplasty in the right patient can be a great operation. And the indications here are advanced, though really quite isolated, patellofemoral DJD. That's failed non-operative treatment in the setting of normal alignment and good motion, so a minimum of 10 to 110 degrees. Contraindications are early global arthritis. They may show you an MRI with tibiofemoral arthritis, which would contraindicate the patient for something like this, or even a weight-bearing x-ray, like here on the right-hand side, of a tibiofemoral DJD. The setting of inflammatory arthropathy or uncorrected malalignment and instability and CRPS are going to be contraindications to this. They have quite high five-year survivorship, though progress in about a quarter of patients to tibiofemoral degeneration, requiring conversion to formal total knee arthroplasty, though it may be a very reasonable intermediate procedure for certain active patients with isolated pathology. The patellar clunk syndrome is something to be aware of. There have been several questions I've seen about this. And this is painful patellar crepitus in a clunk after total knee arthroplasty. What they're looking for here is for you to do an arthroscopic debridement. And this typically alleviates the pain and crepitation and improves function in ADLs in total knee patients. A quick question related to that. Use of knee arthroscopy following total knee arthroplasty is most effective in treating which of the following conditions? And that's going to be patellar clunk. So I'm going to take a quick break, take one breath here, and then we're going to go over some meniscus for the last 20 minutes or so here. Thankfully, most of the meniscus stuff is not really too difficult. A lot of the standard stuff that we all know, things like blood supply, things like vertical mattress sutures, things like this. So as far as meniscus, again, we're going to go through some anatomy, some tear types, some parameniscal cysts, the discoid meniscus, and briefly on things like meniscal transplant. So very high water content. The majority here is type 1 collagen. The meniscal femoral ligaments are important. They arise from the posterior lateral meniscus attaching across to the medial femoral condyle. Remember, if they do ask you about attachments to the lateral meniscus and the lateral meniscal femoral ligament, that they're alphabetical. So the anterior meniscal femoral ligament from the lateral meniscus is that of Humphrey. The posterior meniscal femoral ligament is that of Risberg. And I just remember them because they're alphabetical. The medial meniscus is semilunar. It's wider posteriorly. The anterior horn sits anterior to the ACL. They do like the anatomic relationship type questions. The posterior horn is between the lateral meniscus and the PCL. Its AP translation is only about 5 millimeters. And the decreased mobility is thought to participate in the situation where we observe increased tear incidence in those meniscus tears medially versus laterally. The lateral meniscus is more near circular. The anterior horn is adjacent to the anterior portion of the ACL. And the posterior horn is anterior to the medial meniscus. It covers more tibial articular surface, about 84% than the medial does. It has a similar anterior and posterior width. And its ATP translation is going to be about twice that of the medial meniscus. The vascular anatomy is, again, worth noting. The medial lateral inferior geniculate arteries supply the capsule and the anterior portions of the meniscus, while the middle geniculate supplies the posterior portion of the menisci. Again, one of these just small things I think you've got to look at and just commit those to memory. We're all aware of the perimeniscal capillary plexus that Arnosky showed us years ago and the vascular anatomy based on diffusion and the red, red-white, and white zones. The peripheral supply, about 20% to 30% of the medial meniscus, and only about 10% to 25% of the lateral meniscus. Again, meniscal zones, be aware. There may be a question certainly related to healing of meniscal repair in that setting. So subtotal meniscectomy, if you're given the option, avoid this. It's not going to be the answer if you're given an option to potentially try to preserve or maintain meniscus. In the setting of subtotal meniscectomy, the contact area on the condyle and the tibial plateau will be reduced by 75% and the peak load increased by over 200%. ACL graft force in the setting of a posterior horn medial meniscus tear will increase 30% to 50%. And be aware of Fairbanks changes, those of sclerosis, joint space narrowing, and osteophyte formation, which is really post-meniscectomy arthritis. Partial meniscectomy is going to retain some of our meniscal function, prevent, hopefully, some peak concentration of forces. And even a small rim may be helpful, so preserve as much as possible. Every bite does indeed count. And root avulsion, a super hot topic. Don't miss a root avulsion. I think that this is now really well-accepted and certainly good fodder at this point for an exam question. The problem with the meniscal root avulsion is really loss of the hoop stress and meniscal extrusion, thus leading to this cascade of increased peak force and contact pressure. So repair this if possible. And I think they'll give you a setup where they'll show you an MRI that has either the go sign, complete absence of the meniscal root on the MRI. It'll just be as if it's completely absent. And they'll show you a video of someone tugging on the root. A similar thing to that ramp lesion, too, where the medial meniscus may have more than four or five millimeters of translation. And you can really pull that meniscus in, even though it doesn't look like it's completely separated. What they're looking there, the answer is to repair the meniscal capsular separation. So again, I'm going to whiz through these just for the sake of time. These yellow ones are all within your handout. So meniscus tear, this diagnosis is going to be based on a history, pain, swelling, and mechanical symptoms. So really a focus on mechanical symptoms. And I think if they're asking you to treat these, especially in light of several recent year New England Journal articles and things calling attention to successive non-operative treatment in degenerative meniscus tears, I think that really reliance on mechanical symptoms is important in the question stem if they're trying to lead you down that pathway. As far as exam, joint line tenderness, about 80% of medial meniscus tears are going to involve the posterior horn with posterior medial joint line tenderness. Patients are typically going to have a fusion pain with hyperflexion. And they may tell you about a McMurray's test, though statistically it performs relatively poorly. Imaging, on MRI, know that this is about 90% accurate. There certainly can be high false positives in children. And they may ask you to rely on your physical exam more for a diagnostic arthroscopy in those athletes. And a false positive in asymptomatic patients. So about a 30% to 40% false positive rate, what that means is meniscus tear present in an asymptomatic knee in the fourth decade. So again, don't be fooled by them heading you down that pathway. I think we're all aware of this classification. And what we're looking for is signal that communicates with the articular surface of the meniscus. And looking at things like displaced fragments and altered morphology in the setting of a more complex tear. What about those degenerative tears? They're typically going to set you up in a patient that's older than 40. Twisting injury is common. They may tell you that they stepped off a curb or had an awkward step off of a set of stairs. In the setting of pre-existing degenerative changes, these unfortunately have quite minimal healing capacity, are often going to be more on the spectrum of horizontal cleavage, flap, or complex tears more common versus the traumatic meniscus tear. And the setup here is going to be a typically young athletic population. Most often are going to be trauma related. Many are associated with ACL tears. And the vertical longitudinal tear is going to be the most common. I point out on the bottom right here, be able to identify this. This is the double PCL sign, which is a flipped bucket handle meniscus tear that's incarcerated in the intercondylar notch. And that seems to be a common testable image feature. Repair indications are those of an unstable full thickness tear with 5 millimeters of meniscal capsular junction. And this is excellent success. The moon data shows us about 20% failure at five years overall of those that are repaired. The ability to technically stabilize and co-opt a tear in the middle and outer third is still superior to excision. So it's going to be helpful to try. I think we should all, just as an editorial, be card carrying members of the Meniscal Preservation Society here. And I think a lot of the question writers believe in that. So they're going to probably try to make that the answer for you if given the opportunity. What is the ideal tear for repair? This is going to be an acute vertical and longitudinal tear that's going to be at the vascular periphery, so adjacent to the meniscal capsular junction, in a young patient, and either with a stable knee or in the setting of a concomitant ACL reconstruction, which have shown to be the most beneficial situation for meniscus repair. What about contraindications? So partial thickness tear or incomplete tears, short longitudinal tears, typically those that are peripheral less than a centimeter, and certainly involving the posterior aspect of the lateral meniscus, and in the setting of intact meniscofemoral ligaments, those are the best to leave alone. A radial tear, this still remains really controversial. And I think that this is probably not going to be testable material, because I think now with some of the new devices and adjunct, there are certainly reports coming out that these can be successfully treated. Certainly in younger patients, I would have a hard time believing that there's going to be a test question based on that. Horizontal cleavage tears, I think the standard here, as far as test question answering goes, is going to be to debride the unstable leaflet. There's quite good biomechanical data that shows that you can still maintain the hoop stress by leaving the stable meniscocapsular attached leaflet intact and untouched. And degenerative tear is typically a contraindication for meniscal repair. What about healing? The most important factors are rim width. So if there is a rim that is less than 5 millimeters and their ACL status, so the knee has to be stable or you have to stabilize the knee at the time of repair. Those are critical factors. Things that are less important are going to be tear length, if they are medial or lateral, their age, and the tear age, or the chronicity. Enhancement of meniscal repair, hemarthrosis, or the setting of ACL reconstruction. I think many people will do a microfracture of the notch to stir up a hemarthrosis in that setting. You may be asked about that. Things like adjacent synovial abrasion, trepanation, creation of vascular access channels, placement of a fibrin clot, or things like platelet-rich fibrin matrix or PRP certainly are all within the realm of enhancing meniscal repair healing. About 90% in conjunction with ACL reconstruction, 70% or so if isolated, and 40% success in the setting of ACL deficiency, so really kind of harping on the fact that stability is really critical. What about techniques? Inside-out is still going to remain the gold standard. Beware of the incision and beware of the approach and of the saphenous nerve. So this is saphenous nerve on the way in. Lateral meniscus, again, is going to be a posterior lateral incision, dissect between IT band and bicep. And they're going to ask you where to go. They're going to give you this in the question stem. So look at the approach and be aware, understand where the interval is and the relationship interrelatedness of these structures and what's in danger here. Vertical mattress sutures have been shown to have the highest pull-out strength. I think that still remains the gold standard. Certainly, there has been now, I think, quite a bit of supportive data for all inside devices. But I think that that still remains quite controversial. The knee position for these to be tied in, you may see this at the medial meniscus should be at about 20 to 30 degrees, the lateral meniscus at about 60 degrees. The all-inside techniques avoid a counter-incision. They may be slightly more difficult to oppose anatomically the edges. The historical problems here are articular cartilage damage and avoidance of deep posterior capsular penetration for neurovascular injury. Those are the things that they're going to try to set you up with a question on. The complications here are the general surgical complications that we're aware of. Double PCL sign in that question. Let's take a look at these questions. They really seem to stress many common themes. What about meniscal cysts? So this is typically the result of micro and macro tears in the meniscus that allows like a one-way valve, essentially, of synovial fluid to extravasate through the parameniscal cyst into the posterior medial soft tissue, adjacent typically in the traditional position next to the semimembranosus. The tear communicates with the fluid-filled cyst on MRI, and the standard treatment here is going to be to treat the meniscus back to the bleeding capsule, decompress the cyst that can be done arthroscopically, that can also be done as an adjunctive mini-open procedure. And what the thought is is that the scarring of the cyst and the treatment of the capsular rent prevents recurrence. What about the discoid meniscus? So this is going to be a setup where you have knee snapping in a child, typically less than 10 years old. That should raise that flag or set off that bell that this is a discoid lateral meniscus until you prove otherwise. They may show you an X-ray like this, where you actually see lateral joint space widening compared to the medial joint space. An MRI is diagnostic here, and there are multiple different types of these. What they're going to try to show you, I think, the strict criteria is 5 millimeters in three consecutive MRI cuts. So if they give you that question stem and they show you three consecutive MRI cuts, that's a discoid meniscus. If they are asymptomatic, they do not need to be treated. If they are symptomatic and they've developed a tear, saucerization arthroscopically is the standard of care. If they're a symptomatic type 3, this is the Risberg variant. This is that they have no root attachment other than the meniscal femoral ligament that needs to be repaired or stabilized in conjunction with saucerization. I think that that would be really difficult to ask a question on, but just be aware that that's a situation. They may ask you to repair the root in the setting of saucerization of a discoid. You can see here quite thick meniscus across the entirety of the condyle. What about meniscal allograft transplant? This is our last topic. The objective here is to relieve pain and decrease force potentially on ACL graft, protect the surrounding cartilage or a cartilage restorative procedure with the thought of prevention of post-traumatic arthritis. I think the jury is still out and things like osteotomy are really kind of coming back into favor and people are still not really understanding, I think, what role each of these plays. The traditional meniscal allograft indications are going to be a previous total or subtotal meniscectomy, isolated unicompartmental pain. They may set that up by telling you that the patient was put into a compartment unloading brace temporarily and had excellent relief. They failed nonoperative treatment. They're skeletally mature, typically less than 50 with normal or near normal alignment in a stable knee. Or they will tell you or set you up in the situation that a patient needs concomitant ligament surgery. Contraindications for meniscal allograft are going to be things like inflammatory arthropathy, crystalline arthropathy, uncorrected malalignment, infection, or advanced arthrosis. This is important and the processing is still critical. So you want to avoid irradiated, freeze-dried, or glutaraldehyde-preserved graft. So if you're given the option of a fresh, frozen graft versus any of these other options, these other options are the wrong answer. These need to be sized within 5% of the native meniscus. This is both done by x-ray and MRI. This needs rigid fixation of the horns and peripheral suture repair. Peripheral healing is indeed reliable in greater than 90% of patients. This is going to be shown to heal to the periphery, at least by scar, or be held stable by the suture. The long-term biomechanical function is still questionable. And the 10-year most accepted survival rates for medial are about 75%, lateral about 70%. Complications, the most typical are going to be re-tear, shrinkage, extrusion, or immune response. And the immune response is going to come from those previous treatment options is how that question is going to be set up for you. So take-home points here, anatomy is always fair game, even though we know a lot of the basics of the patellofemoral joint and the meniscus. They may throw these questions, like I've pointed out, about the geniculate arteries. So just take a look at those diagrams. Make sure that you interpret the images correctly. So again, like that question I tried to show you illustratively, they set you up thinking that it's going to be a patellar stabilization procedure, but it turns out to be a pivot shift bone bruise. And they want you to answer that the ACL is torn. Remember, patellofemoral pain or initial dislocation, the most likely answer there is going to be non-operative treatment. Surgery, they're going to walk you down this pathway for surgery when non-operative treatment has failed. Again, like I think I pointed out, they're going to try to get you or want you to make the choice of sooner surgery in the setting of a patellar instability episode with osteochondral fracture. So be aware of that. Reconstruct the MPFL. Consider tibial tubercle osteotomy. And I think that that is really the standard. I think it still may be a little bit on the controversial side, but there is some good AJSM data that shows that for higher level athletes, even in the setting of tibial tubercle osteotomy, that those that had a concomitant MPFL had a higher return to play and higher return to their previous sport. That is certainly testable material. Repair the meniscus if possible and reconstruct the ACL if given the opportunity. Again, these are my references. Thank you. Good luck. Everyone, you guys are going to do great. And as you'll see here, there is a whole set. This will all be available to you after the course. Another 25 questions or so in my slide deck, as well as the ones that were in there. So thanks and good luck. I'm happy to take any questions if you guys have anything.

anatomy

biomechanics

physical examination

imaging

treatment options

patellofemoral conditions

meniscus conditions

soft tissue restraints

knee layers