 This is a 15-year-old female. She had a volleyball injury. Evaluate for anterior cruciate ligament tear. I'm going to go three up. You can go two up if you wish. I'm going to pull down my axial, my coronal, and my sagittal water-weighted sequences. Now if I'm after patello femoral disease, I prefer an axial gradient echo with fat suppression. Very often I'll use a T1 gradient echo with fat suppression, but for my garden variety knee, high-quality, high-resolution T2 weighted imaging is just fine. T2 imaging is there to help you with injury dating. No, I don't mean Cupid.com. I mean dating. Is it old? Is it new? Is it subacute? So it is not a detection sequence. It is a refinement sequence. Now the fat suppression T2 pretty good, but not my first choice for detection. My first choice for detection is the proton density fat suppression, which is on the far right. This is my detection sequence, and I prefer to have a TE of 40. T is a little too short here. T shouldn't go below 40 or above 50 in a PD fat suppression spur, special, or spare. Detection, pretty good detection. Dating. I'll also have a T1 weighted image. This is my fat-weighted anatomy image. It's also a very strong skeletal sequence. I'll also have some specialized views. For instance, I'll have a view right along the line of the anterior cruciate ligament right there. If the cruciate ligament runs like this, then my sagittal will go right down the barrel of that, and it'll be a sagittal oblique. This one happens to be very up and down, so it's almost a straight sagittal, but it shows what we needed to show, which is the status of the anterior cruciate ligament. It's pulverized. What is all that stuff? Blood, gore, inflammatory tissue, pseudoligament. There's nothing there. We can confirm that in the coronal projection. There's our ACL. It's going on the road to nowhere, right? It stops right there. That is all ripped, destroyed tissue. But this is the meniscal section, so there's got to be more wrong than just that, right? Now, I haven't shown you one other pulsing sequence called gradient echo. Gradient echo is used for articular evaluation, for cartilage, for interarticular bodies, and we'll see a lot of gradient echo coming up. So that's a brief introduction to the pulsing sequences. So I'm sure many of you have noticed the medial collateral ligament is abnormal, especially at its distal attachment site. We can't evaluate the medial collateral ligament by layers, an outer layer, cruise layer, a middle layer, the tibial collateral ligament. Unfortunately, it's also called the superficial portion of the deep MCL, so it has a weird name. Let's go with one, two, and three for simplicity. There are some other nomenclatures that are used, too. But as we get deeper, we get into the capsule and the meniscocapsular attachments, like the meniscofemoral attachment. It should go here. It is over here ruptured. The menisco tibial attachment or coronary ligament, it should be nice and tight. Not like a swing right here, or a loop, or a j-hook. It shouldn't look like that. It should be tighter. It's stretched. It's abnormal. So all three layers of the MCL are abnormal. So I've looked at this case, and in five seconds on the coronal image, I know what happened. I know this patient had a valgus pivot shift. How do I know that? The bone pattern, anterofemoral, condyle, and paction fracture. And the MCL is destroyed. So it had to be. It absolutely had to be this. Let me get my model. There had to be a valgus event. And there also had to be a pivot shift, whereby the tibia is shifting backwards relative to the femur. So it was a valgus event and a shift. And those two things produce a series of other abnormalities, a cascade. I know what I'm looking for. I'm looking for an ACL. I'm looking for an MCL. Or, said another way, the ACL and the MCL tells me it's a valgus pivot shift. Now that I know it's a valgus pivot shift, I'm going to the sagittal to make sure that the back of the menisci are okay. Because remember, when you do this, when you do this, when you pivot shift that knee, when you translate, when you have translation of the femur on the tibia, what happens to the structures that attach the menisci in the back? They're under stress. They injure. They tear. They rupture. And these are known as meniscocapsular injuries or ramp lesions. Another stream of consciousness abnormality that has only become apparent in its importance in the last five years. We've got a problem laterally. So on the lateral side, you should have a lateral meniscus that does this with two fascicles, a superior and an inferior fascicle, right there. They should be right here. And instead, we've got something that looks like mush gray, intermediate signal intensity tissue. Let's see if we can find any attachment. Well, there's a rolled up piece of an attachment. There's another piece of an attachment. This is all capsule. Here's a semblance of an attachment. So there is a meniscocapsular tear. I don't use the word separation unless I see the meniscus migrating. But technically, the meniscus is separated. But I use that as a more severe, more abundant term. And I use it when the meniscus is flipped or moved or migrated. This one is forward a little bit. So I would call it a meniscocapsular tear laterally involving the superior and inferior fascicular attachments that go through the popliteus hiatus that's going in the body. And in the conclusion, it'll say postural lateral meniscocapsular detachment. Let's go over to the medial side. Okay, let's blow this one up. I'd like you to follow along with me if you can. You can see me on the screen. Now, if you look very carefully, there is swelling in the capsule. This is all the capsule right here. That line is an injury to the capsule. And that is a vertical tear right at the interface between the meniscus and the capsule. It virtually goes from top to bottom. This is a ramp lesion. So we can grade ramp lesions. Let's do that. Some of our surgical colleagues are very interested in these. One of my colleagues called me up and said, hey, have you ever heard of a ramp lesion? I said, yeah, about seven years ago. He's a sports medicine doc. So it has just entered the orthopedic community in the last three or four years. He said, how many do you have? I said about 5,000. He said, oh, let's write a paper. I said, well, okay. If you can get me some fellows to help me, I'll be happy to write that paper of our 5,000 ramp lesions. Why am I telling you that? Not to impress you because it's so common. It occurs with virtually every pivot shift. So we can grade them. If you have a little lesion on the bottom, it's a one. If you have a little lesion on the top, it's a two. Actually, I'll take that back. I'm sorry. If you have an injury back here in the capsule, it's a one. If you have an abnormality on the bottom, it's a two. If you have a partial abnormality on the top, it's a three. If you have it all the way from top to bottom with the capsular injury like we have here, maybe the bottom almost involved, it's a four. If you have a second vertical tear, now it's a five. Ramp one, two, three, four, and five. What can we get out of the axial? Well, we can see the MCL injury, but mostly the axial is to look at the patellofemoral articulation, its shape, its contour. And this patient has a natural arthrogram. You don't need to put contrast in this joint, which by the way we almost never do an orthopedic MRI anymore in any joint because it's not necessary once you reach expert level. Now you can also scroll around and look at the anatomy, if you're familiar with it, and one piece of anatomy that sticks out is this one. What is that object? That is the dead laying down stump of the anterior cruciate ligament. It's a pseudo mass. You can see it right there. It's kind of a pseudo mass rolled up in the fat. So what would the conclusion look like in a case like this? Pattern of micro and macro-tribecular, depressed fracture, subcortical, anterolateral femoral sulcus with MCL class three injury or tear. Period. Findings consistent with pivot shift mechanism of injury that includes A, miniscule femoral detachment, B, postural medial, ramp lesion, type two, C, anterior cruciate ligament, transaction, and then the effusion and the rest of the stuff would go in the body of the report. So ACL, MCL, miniscule capsular injury on the medial side, and one more thing I forgot to add in the conclusion, postural lateral miniscule capsular detachment. Well, there's a lot more in that case than you thought, right? You thought ACL, MCL. I bet some of you didn't think there was meniscus pathology and you would be wrong. Shall we move on? Question. Do I talk about pleica? Everyone has a pleica. Pleica are embryologic septal reflections. Pleica, uncommon to rarely produce symptoms. Most commonly, superpatellar and medial parapetella. So no, because it's a normal variant and is present in every person. I don't talk about pleica unless the patient has anterior knee pain. The patient has pain with sitting as I'm doing right now. The pain gets better when they stand up and walk around and is relieved. And it's a patient at risk for pleica syndrome, somebody that's sitting a lot during the day. And I don't have another explanation for the patient's clinical syndrome. So I wouldn't use up your valuable time talking about pleica. Otherwise, that'll be two sentences in every report you ever give for the rest of your life. Not a good use of your time. But sometimes it is relevant. Are there any other questions? Let's go.