Hopefully everybody's able to stay awake. I was in your shoes a very short time ago. You've already made the most important step in passing this test, which is being here, having that booklet. If you do fall asleep, everything on my slides are in my handout. Some things actually are in the handout that are not in the talk, that are not as emphasized through the previous test questions. I've put them in there for completeness. The colors didn't reproduce in the handout in the slides, but what you'll see up here if you're barely able to stay awake is anything that's highlighted, either red or yellow, has either been in a test question or in a review question, or I saw on the exam previously when I've taken it. We're going to go through patellofemoral quickly and then meniscus quickly, and I have a ton of questions. Those questions are, again, all in the handout. If I breeze through them here and you guys miss them for time purposes, just remember that they're all there, so don't worry. We'll get started. My disclosures, and we'll talk a bit about anatomy, mechanics, exam and imaging, hopefully really pertinent to the exam here. We'll go through generally what is tested and testable in regarding to patellofemoral pain syndrome, malalignment, instability, plica, which was just touched on, tendonitis, some Osgood-Schlatter extensor mechanism. I'm going to briefly touch on OCD and not to belabor the point from what you've just heard previously, and then IT band syndrome. So the anatomy and biomechanics, both active and passive restraints are important, and the soft tissue restraints are most important in full extension, and 0 to 30 degrees. The articular congruity is going to have the patella making contact with the trochlea and holding that patella stable beyond that of 30 degrees. The static restraints are generally the MPFL, the medial patello-tibial ligament, patello-meniscal ligament, the retinaculum, and the vastus, though this is also contributing as a dynamic stabilizer. Take a look at the medial layers of the knee. Layer two has generally been what I've seen tested, and that contains the MPFL, so particularly with the emphasis on anatomic MPFL reconstruction recently, you'll see that that is a frequently testable layer one, remember deep fashion sartorius. The superficial MCL and the MPFL layer three is capsule, or what you'll see as deep MCL, and those are synonymous and the same. The MPFL resists 60% of lateral translation and subluxation, greatest in extension, and you may see that. The patellar tendon length is about four and a half centimeters. Its width is about three centimeters. This is a question that showed up that the quad tendon is two times that of the thickness of the patellar tendon. Not sure why exactly they want us to know that, but that's important. The VMO attaches at a pennate angle of 55 to 70 degrees from its attachment at the superior medial patella. The trochlea generally has a depth of about eight millimeters. Remember the lateral facet is going to be higher or more prominent if you need to use that for orientation on some imaging that they don't give you other orientation, and contains the thickest cartilage in the body, so that can be five millimeters or even sometimes more than that. The increased moment arm is really the primary function here of the patella, and this is most active in terminal 15 degrees of active knee extension. Remember that the inferior third is non-articular, devoid of articular cartilage, so if you see a fracture there and they ask you if you should do a restoration or an ORIF because of cartilage, that's not the correct answer. What about the blood supply? The geniculate arteries provide the extraosseous anastomotic ring, and the functional blood supply goes a little counterintuitive, and it generally goes from distal to proximal. This is also, I revisit this with the meniscus blood supply, and there are a couple little confusing things that are just small points that you have to memorize and recognize those buzzwords which we'll get to in a couple more slides. The contact areas, again, engages the groove about 20 degrees for the patella, the quad tendon contacts the femur, and then the patella is out of the groove at about 90 degrees. Remember that the contact area moves proximal, and the surface area increases as the knee goes into higher degrees of flexion, and the pressure is highest between 60 to 90 degrees. So a lot of these things, again, highlighted here, and I apologize for them not showing up in color on the printout, but these are the things that you just have to commit these to memory, look at them, and remember when you see them that those are the right answers. What about joint reaction forces? So with level walking, about half of body weight across the patella femoral joint. With stair climbing, about three times that of body weight. A 90 degree isometric contraction, six and a half times body weight. And with a squat, a pretty significant almost eight times body weight. So a couple of questions, which of the following concerning the extensor mechanism is true? I'm going to go through these sort of quickly. The patella increases the lever arm of the quadricep. What about primary restraint to lateral patellar displacement? And that's going to be the MPFL. Normal knee, patella centralized in the trochlea, just like we talked about, 15 to 20 degrees. The central quad tendon is not half as thick, but twice as thick. So what about physical exams? Some things that you may see come up. In general, we all know about this, but looking at limb alignment, ricervotum, atrophy, hindfoot valgus and overpronation may be important or may be related here. Patellar tracking and generalized joint laxity. So you may be asked or you may be shown a video of a J sign. This is lateral translation and as the knee is extended into full extension, crepitation or an extension lag are all going to be part of the sitting exam that you may see a video of and they may ask you to make a diagnosis from that. The supine exam, you've got to examine the hip and there's a question on this later on, but make sure that if you're asked, remember, you know, the two, the old adage of the joint above and joint below. Remember that the obturator nerve innervates both across the hip and the knee. Examine the IT band and IT band tightness with the OBER test. Palpation of fusion and hemarthrosis as well as tenderness and stability are important for the patellofemoral joint. So quadrant glide will be described. You may see a question on this in regards to what's normal or abnormal and abnormal is greater than or equal to three quadrants. So one to two quadrant glide laterally with the knee in full extension is normal. This is generally going to produce patellar apprehension and in the setting of a recurrent patellar instability events or patellar dislocation, this is going to be the, you know, keywords that are going to lead you down an operative type pathway. Lateral patellar tilt, you should be able to passively elevate the patella greater than five degrees. So if you, if you're given a scenario where the patient has less than or equal to five degrees or zero tilt compared to their contralateral side where they have five to ten degrees, they're trying to head you down a pathway of identifying that there's a tight lateral retinaculum or fixed lateral tilt and they're probably going to ask you to do something about that. Be it lateral release or lateral retinacular Z lengthening or something like, like this in the setting of a patellar realignment or a patellar stabilization procedure. Radiographs or general radiographs or apilateral, the Merchant or Loran or sunrise view, I think it's a bit out of the scope to ask you to like look at them and identify, but there are some differences and that may be worth looking at the differences there. I don't think that they're generally testable. Peak is generally also not specifically helpful for the patellofemoral joint. Patellar height is important, particularly considerations of Alta and Baja. The patellar length again is about four and a half centimeters and there is indeed a negative correlation between patellar tendon length and the MPFL width. So patients at risk may, may have more Alta and a smaller MPFL leading to increased risk of instability. Measuring this, there are several ratios that we know about, Insul Salvati, Blackburn Peel. Remember those and have an idea about what they look like. A lot of times I think, you know, we eyeball these x-rays so much. You can tell by Gestalt generally with a simple view or simply looking at that x-ray if they're, and I think for this test, they're not going to make things ambiguous. It's going to be clearly Baja or it's going to be clearly Alta if they're asking you to make a decision based on that. The shape and depth or sulcus angle can indeed be important in regards to evaluation here. Make sure you recognize lateral tilt and subluxation. The bradella patella is a good indirect sign. If you see that, this is described as an avulsion off of the medial patella at the origin of the MPFL that is a sign associated with recurrent lateral patellar instability. MRI is generally going to show us a hemarthrosis, oftentimes lateral patellar subluxation. The characteristic kissing bone bruise on the lateral edge of the femoral condyle as evidence of a recent transient lateral patellar dislocation. What you're really looking for is osteochondral fracture. And the reason being is that for most patients, and I think for purposes of this test, probably one of the only first time patellar dislocator surgical intervention is in the setting of an osteochondral fracture. So they're generally not going to lead you down the pathway of wanting the answer to be to do surgery on a first time patellar dislocator in the absence of an acute osteochondral fracture. So if you see that, that's really the indication to get the MRI and that's really what you're looking for because that is the indication in that patient to do a surgical procedure. Otherwise, these are almost ubiquitously going to, the correct answer is going to be to treat them non-operatively at their first initial dislocation. You're going to see MPFL tear and you want to look for other internal derangement because some of these patients, as I have seen and many of you probably have seen clinically, they sometimes have multi-ligament injuries, either MCL or even combined ACL and MPFL injury in the setting of both. So these are what those are going to look like. You can see on the lower right an acute osteochondral fracture. This is a femoral based MPFL tear and you see the contusion here from a transient lateral patellar dislocation. The congruence and patellar tilt angle, I wouldn't think that they're going to make you measure these, but certainly to be at least somewhat familiar, there are multiple of these described in different ways. I don't think that they generally predict treatment or predict indications for surgery or not and so there are some other measurements that we're going to make here that are much more important and this is one of them, the TTTG measurement and that's the tibial tubercle to trochlear groove measurement measured perpendicular to the posterior condylar axis through the center of the groove and then that measure generally to the center of the tibial tubercle. So if you see that above 20 or even borderline close to 20, this is going to be an indication for tibial tubercle osteotomy in a patient that has lateral patellar recurrent instability. So this is a 12-year-old football player, two weeks, had sudden pain while blocking, unable to continue to play, x-rays normal, two weeks of anti-inflammatories but didn't get better, vaguely localizes pain, medial and anterior. Tibial exam is essentially a normal knee exam. Ligaments are stable but I'll point you here, a lot of times I think on these tests they're asking you just to make sure that you read the whole question so the bottom one here they tell you that hip pain is produced with log roll and so the next step is actually a hip and pelvis x-ray and so you're looking for something like a skiffy or hip injury in this player who presents with leg or knee pain. What about patellofemoral pain syndrome? So we're looking at predisposing factors, hip abductor weakness, a shortened quad, abnormal VMO reflex time, hypermobile patella or chondral lesions of the patella or trochlea and again make sure that you're evaluating the entirety of the lower extremity. So non-operative management is going to rule here, physical therapy, bracing, taping, orthotics are of possibly limited benefit here. NSAIDs will help with short-term pain relief though no confirmed benefit from steroid or visco supplementation for these patients so I think that that's controversial enough that probably will not be the right answer on this test. What about operative treatment? Selected patients that have failed non-operative treatment and have a symptomatic loose body or chondral flap. This is the best indication in these patients for an arthroscopic debridement. What about patellofemoral malalignment? We've touched on some of these indices and measures and in regards to tilt and subluxation you want to identify the risk factors, exhaust their non-operative measures and those are PT, strengthening, some bracing and certainly NSAIDs and time is going to be a factor there as well. Patients that have genu valgum or recurvotum are going to be at risk. These femoral anaversion, femoral torsion, external tibial torsion and patellar or trochlea dysplasia are all going to be risk factors so they may set this patient up where they show you a very valgus recurvotum patient and they're setting you up down this pathway of malalignment. So ALTA in addition, VMO atrophy or weakness, tightness of the lateral restraint so that fixed lateral tilt, a tibial tubercle to trochlea groove distance that's abnormal, pes planus or overpronation and a high Bayton score and that's a Bayton score generally over 6 is considered abnormal. The maximum remember is 9 so you get score for 2 bilaterally, right, for thumbs, finger back, elbows, knees backwards and then palms flat on the floor with your knees fully extended is the extra 1, that's why it's 9, not all are bilateral but generally above 6 is going to be positive if you see that as an evaluation of general ligamentous laxity. Patellofemoral malalignment, so isolated lateral release is going to be the right answer only in the setting of excessive lateral patellar facet pressure syndrome so they need to set this up perfectly for you for this to be the right answer on the test and it's going to be a tight lateral retinaculum with fixed tilt clinically, tilt without subluxation, mild lateral facet chondrosis and they are not going to have, they may give you the TTTG but it has to be normal, they're going to tell you that the patient is stable and doesn't have recurrent instability so this situation for this to be the right answer needs to be a perfect setup. You need to maintain the vastest fibers, there's a risk of course of hemothrosis, CRPS, quad weakness and development of medial patellar instability. So causative factors with patellofemoral symptoms include which are the following and external tibial torsion, all the others are the opposites. How about preoperative factors conducive to achieving consistent and predictable results when performing isolated lateral retinacular release and again passive lateral tilt less than five degrees so fixed lateral tilt, all these other ones are going to lead you down a different pathway. Pediatric medial patellar subluxation is best corrected with which of the following and this is going to be reconstruction of the lateral patellofemoral ligament. So tibial tubercle transfer in the setting of a lateral quadricep vector, pulling the kneecap laterally, a straight medialization or the Elmsley triot within the setting of no arthrosis, this is going to be appropriate I think generally, this is the probably most acceptable answer if they're going to nitpick on this is a Fulkerson osteotomy or a standard antram medialization, certainly in the setting of any lateral facet arthrosis. And the antram medial transfer unloads both the distal and lateral patella, lengthens the quadricep lever arm, does however increase the patellar contact area and decreases stress per unit area. In cadaveric study, the optimal displacement is shown to be about one centimeter anterior and medial of about 0.5 to one centimeter, clinically we may make some different measurements based on the magnitude of their TTTG and trying to restore them back to a more normal scenario but this is what's been shown in cadaveric study to be optimal. So the intermedial tibial tubercle transfer best unloads which of the following damaged patellar articular surfaces, and again this is back to the biomechanics of distal and lateral offload within AMZ. What about lateral patellar compression syndrome, so again touching now back on the isolated lateral release type of patient, fixed tight lateral retinaculum, excessive patellar tilt and chondrosis, you know the tires are out of alignment here. These patients are going to present with pain, stairs, a positive movie theater sign, pain with patellar compression and lateral facet pain often with again fixed lateral tilt, I think I really wanted to drive this point home. So fixed lateral tilt and inability to evert the lateral edge of the patella. So non-op treatment is of course going to be your probably first through 10th line treatment but if they do come to operative treatment, lateral release, but patellar realignment may be the right answer in the setting of setting you up with those other indices. So either a Mackay and I doubt that that will be the correct question but they could ask you about complications there and that's an anteriorization concomitantly of the tibial tubercle and so the question there may be things like the most common complications of skin necrosis or wound problems which was the big issues with that procedure historically, either a straight medialization or an anterior medialization. So switching gears a little bit, IT band friction syndrome and this is caused by contact between the IT band and its underlying lateral femoral condyle often seen in runners and cyclists and given the common moniker of runner's knee tenderness is generally located directly over the IT band bursa proximal and lateral to the patella itself worse with the knee at about 30 degrees of flexion. Usually these patients are going to have a positive OBRA test with a tight IT band clinically. Nonoperative treatment again is our treatment of choice. Rehab is generally often successful plus minus sometimes things like iontophoresis or steroid injection you may see as adjunct treatments that they may ask you to try. Operative treatment is also successful. This is Tom's data, surgical excision of the posterior IT band with IT band bursectomy and these are only indicated in refractory cases but successful if they fail nonoperative treatment and if they need that. Acute lateral patellar dislocation generally the history there is going to be a twisting injury, they feel that the knee gave out, they often feel a pop, they have immediate and generally very tense swelling. So you may hear that, they may say that in the description that it's a tense effusion and diffuse pain. I think a lot of our knee jerk reaction, you know, when we start reading that question and we see a non-contact injury or twisting of the knee, heard and felt a pop with a tense effusion, our knee jerk reaction is going to be ACL, they're ruling out ACL but remember that acute patellar dislocations often present the same way. The MPFL is going to be torn in almost 90 plus percent of those patients and it's often at the femoral attachment but it can be along either the femoral attachment mid substance or at the patellar attachment. There's generally a concomitant medial retinacular tear, can be chondral damage and again osteochondral fracture is critical, that's really your indication for MRI and osseous contusion that I showed you, that kissing lesion that we showed. So you may see an image like this on the bottom left. The patella can generally have chondral or osteochondral lesions in a very high percentage of these. Some of these patients may be maltracking to begin with, so you may see chondromalacia by default, lateral femoral condyle thankfully less so, but beware if you see that picture they're going to ask you to operate on that patient, that's an indication for an acute surgical procedure. So acute dislocation of the patella is associated with what percentage of MRI documented injury to the MPFL, you know if you use the general resident 80-20 rule you'll get that one right. If no osteochondral fracture or loose body then non-operative treatment is what you want. Control their swelling, you may immobilize for the first two weeks or so and then you want to get them going with some immediate range of motion, quad strengthening and you may want to use a lateral buttress brace that can be helpful for their stability as they're rehabbing. If they do have osteochondral fracture or loose body, underlying predisposing factors or perhaps in a high demand athlete you would, that would at least push you towards consideration of operative treatment. At the time of arthroscopy you can debride, remove the loose body. If there is bone on the back of that osteochondral fracture and it's of any reasonable size most likely you will want to try to fix that and that's difficult to do arthroscopically but most likely that's going to be a mini-open, smaller throtomy to do that. Operative repair of the MPFL, I think this is probably controversial enough that you will not see questions on this of whether you imbricate or proximal medial reef or MPFL reconstruction or pants over vest, the VMO or some combination. But at least be aware that those are options and there's certainly data supporting just about any of those treatments, however, I would say that there's probably a trend towards better outcomes with MPFL reconstruction if you are going to operate on them, similar to the sort of historical literature on posterolateral corner and how reconstruction is now outperformed repair generally. 18-year-old female sustains acute patellar dislocation playing soccer. She has a spontaneous reduction. What factors predispose her to recurrent instability and so trochlea dysplasia is going to be our biggest one there. I'm going to whiz through these so we don't get behind. Tennis player, this is her first dislocation. They're showing you an osteochondral fracture here and they want you to RAF that. This is a good one. Let's go back. This is a good one because this is a trick. They're just making sure that you actually look at the images here. So this is a 15-year-old, comes in and feels like her kneecap came out of socket but went back in and now she's complaining of giving way and MRI is shown. So don't forget what we already know. Make sure you look at the images. They're showing you a pivot shift bone bruise and an ACL tear despite her telling you and despite them telling you in the question stem that she thought this was a patellar instability event. This is an ACL tear. So the most appropriate treatment is ACL reconstruction, not MPFL or patellar stabilization. Those question writers are tricky. They'll try to get you. So risk of re-dislocation over two to five years is at least 50%, at least half are going to re-dislocate and again, failure of non-operative treatment is certainly an indication for surgery with these patients. Specific surgical procedure depends on all these things that we've talked about. Their alignment, their version, their TTTG, what their trochlear morphology is and they're going to have you put that together in just about any of these questions. For excessive genu-valgum or femoral anaversion, femoral osteotomy and a derotational osteotomy may indeed be the correct answer but I haven't seen that tested in this realm. If they have rotational malalignment based on an abnormal TTTG, again, tibial tubercle osteotomy is going to be the answer. They may give you the tubercle sulcus angle. That cutoff is about 12 and again, 20 millimeters for TTTG. And you may consider a distalization if they have gross patella alta. What about NPFL reconstruction? Allograft or autograft are both acceptable. There's very reasonable published literature on both that that's probably not a major contributing factor for recurrence or failure of that procedure. Non-anatomic tunnels is absolutely becoming prominent in the success of this operation and the development of later patella femoral arthrosis, specifically not over-tensioning these patients. So non-anatomic attachment sites for NPFL will dramatically change the contact force and pressure across that cartilage and the thing that I've seen is a two proximal femoral attachment can double the compressive force. And so you want to make sure that this is anatomic. And what that is is the description of Schottel's point, which is the femoral tunnel origin and where we should choose to reconstruct. And that is the confluence of the posterior femoral cortex, the edge of Blumensat's line in the back of the condyle and the center point there is going to be Schottel's point or anatomically with a perfect lateral x-ray of the distal femur, the anatomic distal attachment site of the NPFL for reconstructive purposes. Tension the graft with the patella engaged in the trochlea. Generally, I think a lot of us do that at 90 degrees. That's a bit controversial. I don't think you'll be asked in degree measures, but you may hear or they may ask you if it should be tensioned in flexion and so you want the patella balanced. You don't want to make their patella non-mobile. You just want to restore one to two quadrant glide. You just want to reduce them, remember, from that three or greater lateral quadrant glide. You don't want to over-tension this, which will lead to significant patellar chondrosis. I'm going to whiz through these a little bit. Again, these are all in your handout just for the sake of time. Plica syndrome, Flanagan touched on this a bit, but I'll go through that just briefly. Again, 90% of asymptomatic knees. This may be suprapatellar or medial or infrapatellar. Initially, these are treated non-operatively. If you see that they're persistent, painful, just like he showed that excellent question and persistent painful snapping of a thick fibrotic band over the mediofemoral condyle. That certainly warrants an arthroscopy. What about patellar and quad tendinopathy? These are the results of recurrent microtrauma frequently diagnosed by physical exam. You can use ultrasound and or MRI. Eccentric strengthening is what you're going to see as the general mode of treatment that they're asking you to choose here. Debridement and repair is really reserved for only those with persistent pain and failure of those measures. I was thinking about this, and I think it's probably, again, some other things, adjuncts that we're using are probably still too controversial to ask questions about things like PRP or stem cells or stuff like that. But, you know, I think that may be a bit too controversial for a test like this, but you may see those things as treatments that are a possibility. Again, infratellar strap, stretch, strengthening. You'll see eccentric strengthening will come up frequently. Osgood-Schlatter. So this is an apophysitis. This thankfully rarely requires surgery. Activity modification, stretching, Chopat strap or brace. And this is a fragmentation or abnormality of the tibial apophysis in a skeletally immature individual. Refractory cases or those that are now skeletally mature that have refractory pain or partial tears may be potential patients for an arthroscopic or open excision of those tubercle fragments. Thankfully, that's rare. This question, a 17-year-old basketball player, they're telling you here that he's at 18 months worth of pain. They're showing you that he has a large ossicle here, but that attachment is nearly completely detached. So they're asking you in this case, actually, to debride and repair that. Quadricep tendon rupture, extensor mechanism disruption in general. The quad tendons are generally going to be our older patients in the setting of an age-related degenerative tendon. These are generally proximal to the patellar insertion, whereas the patellar tendon ruptures are generally going to be in our younger patient population in the setting of a normal tendon with an eccentric load, and these are generally distal to the patellar insertion. So surgical treatment is best with early end-to-end repair, non-absorbable suture, or now perhaps fiber tape. Utilize longitudinal drill holes, and this can come up. Longitudinal drill holes are as effective, though transverse drill holes have been demonstrated to be a fracture risk in the patella, or suture anchors are certainly acceptable and biomechanically generally as strong. Rehab and a brace with an extension block or extension lock. What about tibial tubercle avulsion? So this is an adolescent injury, skeletally immature. This represents an apophysial fracture of the anterior tibial apophysis. There is no confirmed relationship with Osgood-Schlatter, so patients that have a painful tibial tubercle, they do not have an association with an apophysial fracture or tibial tubercle avulsion. You have to rule out associated injuries here, and those can be present in about 10%. I would look, likely if asked, with an MRI. Surgical treatments, when these are displaced, and those are the types 2s, 3s, and 4s, are best fixated with internal fixation. These can be done with lag screws, cannulated screws. Important to avoid or make sure your fixation is distal to the proximal tibia physis. Repair the extensor mechanism if that is concomitantly injured, and they may ask you how to monitor these patients, so you're going to want to admit these patients overnight and monitor them for compartment syndrome, because there's a higher-than-average incidence of concomitant anterior compartment syndrome in this entity. What about patella fracture? Generally, this is a direct blow or some sort of indirect combination under the setting of an eccentric load to the patella. They come in all shapes and varieties. If they're displaced, and generally, any articular step-off greater than 1 or 2 millimeters or displacement greater than 3 millimeters in the setting of a non-intact extensor mechanism, so if they're trying to set you up for non-operative treatment, I doubt they're going to make it controversial. They'll tell you that the patient has an intact extensor mechanism. They're going to show you an X-ray that has minimal or absolutely no displacement and no articular step-off. Other than that, you are going to want to treat these operatively. Cannulated screws, tension band, wires, or suture, these are all certainly acceptable treatments. Partial patelectomy, that's most likely not going to be the right answer. This is really reserved for severe comminution. If you have to do that, reattach the patella or quad tendons to the remaining bit of bone that you can salvage. Again, I'm going to breeze through these for the sake of time. This is a tibial tubercle avulsion to fix. What about bipartite patella? This is present in about 3% of the normal population. It's bilateral in half of patients. Generally, supralateral is the typical position, so when you see this on your X-ray in the absence of trauma or pain there, we're going to leave that alone. Excision or lateral release or vastus detachment with repair would be the treatment if that remained or became symptomatic. Rarely is ORIF indicated. What about patellofemoral articular cartilage defects? This is a challenging problem. Begin with a thorough non-operative treatment. There's not great evidence to support what surgical treatment or what they need and in what combination, but cartilage restoration, realignment, and again, individualize that based on the factors present. If you apply all those other things and then apply what you've heard in the previous talk about cartilage restoration, I think that that will put together the correct answer in almost every case. What about DJD of the isolated of the patellofemoral joint? Again, associated with maltracking instability, a valgus knee. Non-operative treatment is going to be the treatment of choice in general. Arthroscopic debridement may be of help. You may consider a lateral release or tibial tubercle elevation or osteotomy with the correct indices or patellofemoral arthroplasty. Patelectomy has extraordinarily narrow indications. Again, combinated patella fracture or post-traumatic arthritis, but expect a significant loss of power, instability, persistent pain. Unfortunately, this is irreversible and you can expect that less than half of the patients are going to have a good or excellent result. What about arthroplasty? So, isolated patellofemoral arthroplasty is indicated in the setting of advanced or isolated patellofemoral DJD. They need to have failed non-op management, have normal alignment based on, again, the indices that we've talked about, and good motion. Contraindications are arthritis, that's early MRI-based only, but not X-ray-based. A high grade of tibiofemoral DJD, any inflammatory arthropathy, uncorrected malalignment, or setting of CRPS. These have a reasonable survival rate and 96% at five years has been demonstrated. About a quarter will have tibiofemoral degeneration and be needed to convert to a traditional total knee, though it certainly is an acceptable intermediate procedure for patients that want to remain active, potentially running, for example, or lightweight bearing activities such as tennis as a staged procedure before they proceed with a knee arthroplasty. Patellar clunk, I've seen this show up as appropriate for arthroscopic debridement following a total knee arthroplasty. This is development of distal pole scar tissue, and this is a question based on that. It's the most appropriate arthroscopic treatment for a total knee. So now I'm going to switch gears, and in the last 20 minutes here or so, we're going to go through the meniscus. Hopefully I haven't put all of you to sleep. And again, all of this is contained in the handout, so if you do need to nod off or if I'm boring you to death, it's all there and you can look at it. So the anatomy and biomechanics, tear types, paraminiscal cysts, tracheoid, and meniscal transplant seem to be most of the testable material. Remember that the meniscus is primarily water and type 1 collagen. The meniscofemoral ligaments, remember those, they're alphabetical is the way that I remember them. So the anterior meniscofemoral ligament is that of Humphrey, the posterior is that of Risberg. The medial meniscus, semilunar, wider posteriorly. The anterior horn attaches anterior anatomically to the ACL, while the posterior horn is between the lateral meniscus and the PCL and has limited mobility, that of only about 5 millimeters. Decreased mobility of that meniscus likely leads to its increased tear incidence. The lateral meniscus, in contrast, is nearly circular. The anterior horn is generally adjacent to the ACL attachment, while the posterior horn is anterior to the medial meniscus. They may ask you those things or they may point to them on a figure and ask you which is which, and by knowing those relationships you can tell. It covers more tibial articular surface, about 84%, similar anterior and posterior widths, and the anterior-posterior translation is about two times that of the medial meniscus. So back to the blood vessels that I mentioned earlier. The major blood vessels and blood supply to the meniscus, this is definitely testable material. The medial and lateral inferior geniculates supply the capsule and the anterior portions of the meniscus, while the middle geniculate supplies generally the posterior portion of the meniscus. So unfortunately one of those just rote memorization things. We all know about the perimeniscal capillary plexus, Arnosky's picture, that generally are originating from the synovium and by diffusion through the meniscus. This supplies the peripheral 20-30% of the medial and less than that, about only 10-25% of the lateral meniscus. We know about the red-red, red-white, and white-white zones as far as blood supply and diffusion of meniscus, and in regards to total meniscectomy, we are going to want to avoid this if possible. In the setting of complete and thorough meniscectomy, this changes the contact area, reducing this by about 75%, but increases the peak load in that compartment by over 200%. So this is going to lead predictably to arthrosis, as we've seen clinically in patients over the years. ACL graft force in the setting of a subtotal meniscectomy increases by 30-50%, and Fairbanks changes of sclerosis, joint space narrowing, and osteophyte, otherwise known as post-meniscectomy arthritis, is predictable for these patients. So what about partial meniscectomy? Our goal here is to retain some of the hoop stress of the peripheral meniscus if possible. This will maintain some of the prevention of peak concentration of force, and even a small rim provides some anterior- posterior stability. So the bottom line is preserve as much as possible. Every single bite of that biter or every turn of the shaver matters. So root avulsion is certainly important. I can absolutely, I think this has now gotten enough press and enough supportive literature that you may see this on the test. Meniscal root injury was I think previously under-recognized. This causes an immediate loss of hoop stress and an extruded meniscus with a significant increase in peak contact pressure and decreased contact area. So the idea here is going to be to repair this if possible, certainly in the right setting in the absence of significant arthrosis. I'm going to skip through these just for the sake of time. Again, they're all in your handout. And there are a lot of them. So meniscus tear, our diagnosis is going to be based on history, that of mechanical symptoms, pain, and effusion. Joint line tenderness, 80% of medial meniscus tears involve the posterior horn, and that should be point tender. Effusion, pain with hyperflexion and McMurray's. Our imaging, we all know about. MRI, make sure that they don't catch you on one of these. Though 90% accurate, there's a significant false positive in children. Children have generally a lot of hypervascularity that may be bands and lines inside the meniscus, but if they're not exiting the meniscal surface, you're not going to call that a meniscus tear or operate on it. And there's a significantly high false positive rate in asymptomatic patients, certainly as we age. And that data is about mid-30% at the age of 45. MRI classification we know of, but grade 0 is totally normal, nothing. Grade 1 is an intrameniscal signal, but we're not really wanting to operate on these. We're calling them a true meniscus tear until they're grade 3, in addition to altered morphology, displaced fragments, and seeing those on multiple MRI cuts. Actually, this is a good one I'll go through quickly. 10-year-old competitive gymnast. She has persistent lateral knee pain and popping with increasing episodes of catching. Exam, she has joint line tenderness, positive McMurray, equally loud but painless pop she has on the unaffected side. MRI revealed no abnormalities, and which of the following is true? And they're asking you here that clinical exam is more sensitive than the MRI. What about degenerative meniscus tears? These are generally in patients over that of 40. A twisting injury is common, often in the setting of pre-existing degenerative changes. They unfortunately have minimal healing capacity, and that's because of what we know due to the diffusion of the blood supply in the meniscus. And these are often complex in nature. They may be a horizontal cleavage tear, they may have flaps or parrot beaks, but complex in nature and often irreparable. This is in contrast to a traumatic meniscus tear in the typically young and athletic population. Often acute trauma related hear and feel a pop, often associated with ACL tear, and vertical longitudinal tears are going to be most common. Repair indications and repair versus debridement is a somewhat controversial topic, but I think there is some testable material here. Repair indications of an unstable thickness tear with at least 5 millimeters of meniscal capsular junction have excellent success with 20% failure at 5 years. That's the moon data. Ability to technically stabilize and coaptate the tear in the middle and outer third is superior to excision in that setting. So if you have to take a chunk of the meniscus, a large chunk, particularly the younger the patient, I think the right answer is going to lean towards repair if at all possible. The absolutely ideal tear for repair is going to be peripheral longitudinal at the vascular periphery in a young patient with a traumatic injury in the setting of a stable knee or concomitant ligament reconstruction. Repair conjure indications, only a partial thickness tear, a short longitudinal tear, a radial tear, and now this is controversial but again I don't think that they would test you on that. You want a read unstable leaflets. There is some data that shows with a horizontal cleavage tear that if there's one leaflet that's unstable and one that is indeed stable that you can maintain some of the biomechanical properties by leaving the other and stable leaflet. So I would leave that if that's an option. And degenerative tears are generally contraindicated for repair. The most important factors in regards to meniscal repair healing are the rim width, the ACL status. So in the setting of an ACL deficient knee even in the perfect meniscus tear you're not going to reconstruct that. It has a significantly high failure rate if you don't stabilize that knee. And you'll see there's a question that touches on that later on. Less important here are things like tear length, if it's medial versus lateral, what their age is or what the tear age is. So enhancement for meniscal repair, hemarthrosis is certainly important and we do see increased healing rates in the setting of concomitant ACL reconstruction. A lot of us think that that may be due to essentially some de novo stem cell or PRP augmentation that we're getting from the hemarthrosis. Synovial abrasion, trepanation of the rim, vascular access channels, fibrin clot and PRP. These are pretty controversial but you may see them as adjuncts and there is some data certainly to support their use. As far as meniscus healing, you can expect a very high rate of healing in conjunction with ACL reconstruction. If they're isolated, certainly less than that. Only about two thirds. And in the setting of ACL deficiency quite poor, so less than half are going to be expected to heal. What about technique? So technique for these is important and provides some very good testable material because it's simply rote anatomy and memorization. Inside out for the medial meniscus still remains the gold standard. A posterior medial incision, just posterior to that of the MCL. Beware of the infrapatellar branch of the saphenous nerve that's often in your field. Dissect deep to the semimembranosus. This is a clinical picture demonstrating what that infrapatellar branch of the saphenous looks like. For the lateral meniscus this is a posterior lateral incision between the IT band and the bicep and then anterior to the lateral head of the gastroc and your risk here is the peroneal nerve. So this is a clinical picture of that. That's going to be, this is looking this is anterior, this is posterior superior up top and in a right knee and so this is on the lateral meniscal repair exposure the LCL and then this is going to be the interval that you're looking to exploit to put your spoon or your Henning retractor and protect that meniscal repair needle from skewering your peroneal nerve. Vertical mattress sutures are going to be your biomechanically most superior construct. They have the highest pull out strength. Zone specific cannulas are helpful, generally a 2-0 or 1-0 non-absorbable suture. Tie these over the capsule. The knee position for tying and tensioning, medial is described optimal at about 20 degrees while lateral at about 60 degrees. All inside has some advantages. It requires no counter incision. It's somewhat more difficult generally to oppose anatomically. Prominent implants historically have caused significant articular damage and that can be a problem. Try to avoid deep posterior capsular penetration and so make sure you set the limit of the device. Not so far. They can actually penetrate the posterior skin and the popliteal fossa. You can create tons of problems. Most of the biomechanical data and even clinical data now I think is becoming supportive that they generally clinically are relatively equivalent but I still think inside out really remains the gold standard in the setting of vertical mattress stitch. Complications here are failure to heal, limited motion, iatrogenic injury, nerve injury, posterior neurovascular structure injury or infection. So again, just rote memorization, inside out lateral meniscal repair, they're showing IT band, bicep and then anterior to lateral head of the gastroc just behind the posterior capsule. This is one showing us the double PCL sign. That's a bucket handle meniscus tear and they're asking you what to do in combination with that and that's associated ACL reconstruction. Again, I'm going to flip through these quickly, make sure that we finish on time. Meniscal cysts, so micro and macro tears in the meniscus essentially allow a one-way valve. This is a pressure related phenomenon allowing synovial fluid to extravasate into the parameniscal tissue which then forms a cyst and generally that fluid because of the diffusion and the pressure within the joint cannot get back into the joint and has to either wait to be treated or to resorb or to potentially rupture. The tear generally communicates with the fluid filled cyst on MRI. You should be able to see that in most or certainly now with higher resolution MRI. Treatment wise, you want to remove the torn portion of the meniscus back to the bleeding capsule. If you can identify the hole, if you can see it, you want to debride the hole, you want to decompress the cyst either be it arthroscopically sometimes through a separate posterior medial or posterior lateral open incision. And generally scarring of the cyst aperture will prevent recurrence of these tears. Again here regarding meniscal cysts which statement is true and these are filled with a gel-like material that's biochemically similar to synovial fluid which is its origin. The discoid meniscus, this is going to be the scenario of a young child generally around or younger than 10 years of age with knee snapping and this can be symptomatic, it can be asymptomatic. The criteria show lateral joint space widening or widening and thickness of the meniscus on multiple consecutive cuts of the MRI. The MRI is going to be diagnostic, a type 1 is complete, a type 2 is an incomplete discoid and type 3 is what's called the Risberg variant and that's an unstable variant because there's no posterior tibial attachment, it's just attached through the meniscofemoral ligament. Discoid, if they're asymptomatic, we don't treat them. If they're symptomatic and they're types 1 and 2 we can saucerize them. If a symptomatic type 3 is seen you want to do a partial meniscectomy or essentially a saucerization as well as a root repair to stabilize the posterior meniscus. Again, we're trying to maintain the hoop stress and prevent an extruded meniscus such that we can decrease the contact force and contact pressure of the meniscus. So a 10-year-old swimmer complains of intermittent popping when he's competing in the breaststroke. His parents say his knee is dislocating. He looks pretty normal. Patellar apprehension is normal. Radiologist reports that radiographs are normal. What's his most likely diagnosis? So asymptomatic knee popping in a 10-year-old is going to be a discoid lateral meniscus. What about a 14-year-old female having lateral knee catching in pain playing field hockey? Never had significant injury. MRI is shown. Mom asks you what's going on. And so again you see that very thick meniscus covering here and this is more frequently lateral than medial. All these others are not correct. What about meniscal allograft transplantation? The objective of this is going to be to relieve pain, decrease forces on a potential graft, be it ACL or cartilage graft and osteochondral graft and protect the cartilage restoration and we're not really sure if this is going to prevent or delay post-traumatic arthritis. The indications here are previous total or subtotal meniscectomy in the setting of isolated and unicompartmental pain. They may tell you that this is a patient that they was put into an unloader brace and had an excellent response. They definitely should be able to show you alignment films or describe isolated malalignment. They failed non-operative treatment. They have closed physes. At or younger than 50 years of age, again with normal alignment and a stable knee are going to be your best indications. Contraindications is any inflammatory or crystalline arthropathy and uncorrected malalignment. So if they ask you if they're heading you down the pathway where they want meniscal transplant to be the right answer and it's in the setting of malalignment, you're going to be asked to correct the malalignment concomitantly. Obesity, previous infection, or obviously advanced arthritis are contraindications. Processing is a critical issue here and this is certainly testable. It is important and it is probably one of the issues that's most important now we recognize clinically for the survival or failure of these grafts. The need for viable cells is uncertain, though fresh frozen grafts are now I think our best choice as we heard in the last talk. What you want to avoid are irradiated, freeze-dried, lyophilized, glutaraldehyde preserved. These are things that are not going to go well for long-term outcomes of these. You have to know that the meniscus cells do have some HLA 1 and 2 antigens which can be immunogenic and a subtle immune reaction may certainly affect healing and have been implicated in failure of these. So when possible if asked, if you see these words these are the buzzwords that you want to look for is the right answers. Things that are like fresh frozen, non-irradiated, and sized to within 5% of the native meniscus both by x-ray and MRI. They need to be rigidly fixed on both horns, either be it with suture, with bone tunnels, or through a bone trough type procedure. The clinical results have shown that the peripheral healing is indeed reliable. The long-term biomechanical function is questionable and about 3 quarters will survive at 10 years both medial and lateral with a little bit better survival medial than lateral. Complications wise we see re-tear, shrinkage, unfortunately meniscal extrusion, and immune response. And again here a question, which of the following factors is most critical to the success of meniscal allograft transplantation, and that's accurate graft size, remember within about 5 millimeters. Regarding allograft transplantation, which is accurate and what they're asking you here is to know, understand that the meniscal capsular junction will heal highly reliably. What about complication with a lyophilized graft, so even if you've never heard that word, you know it's some sort of treatment, which I told you is bad, and so those grafts they shrink, they have significant problems, they show graft shrinkage. So take home points here for the test, anatomy is always fair game, interpret the images correctly, make sure that you read the whole question, if it's an intense imaging question, I would recommend probably reading the answers as well, maybe even before looking at the images, because like a few of those questions I showed, if you look at the images, you may not actually understand what they're asking you, so just those test taking strategies which Dr. Keating is going to go over shortly for us. Patellofemoral pain and initial dislocation, non-op treatment, that's the answer. Surgery, remember only when non-operative treatment has failed, and they'll outline that very well for you. Recurrent patellar instability, remember reconstruct the MPFL, look at that TTTG, if it's abnormal the right answer is going to be a arterial osteotomy. Repair the meniscus if you can, and reconstruct the ACL, remember untreated instability is going to be a risk for failure for all of these treatments. These are my references, and best of luck. Applause

patellofemoral pain syndrome

meniscal tears

test presence

anatomy

biomechanics

treatment options

meniscal repair

meniscectomy

key points