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So the history here was a 28 year old male with right knee pain

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and instability,

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bend the knee after work related injury where the patient hit the knee on work

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equipment, no history of surgery.

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So we have a young patient who has had injury and then, uh, knee pain.

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So, um, I'll just go over, um, my approach.

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How do we look at the cases? Um, so, um,

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I always, uh, like to start, uh, with, uh, uh, a fluid sensitive,

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fat saturated sequence. Um, I always, um,

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will have at least two images side by side.

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I think the first step that I do is I arrange my images in the layout of, uh,

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your packs screen and have all images arranged if there's a prior exam.

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Um, have that, uh, for comparison and for any EMSK study.

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Um, even before you open the MR, uh,

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I think the first step is to look at the radiographs.

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If there's a radiograph available, uh, we should always review that. Um,

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it'll help you, um, pick up findings or get an idea,

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especially like areas of mineralization, um, presence of air,

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which are difficult to see on, um, on mr. Um, you can,

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um, see them easily on, on Mr Images. So first step, look at the radiographs.

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Second step. When you open the mr, um, study, um, arrange your layout,

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arrange all the images that you wanna look at, and then you can, um,

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have your approach and start with the required images.

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So I'd like to look at fluid sensitive sequences. I have, um,

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sagittal and coronal here.

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Starting from one side,

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we are looking at the sagittal images starting from the medial side. Uh,

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we can look at the medial meniscus. Uh,

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we see some abnormal signal along the posterior aspect.

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So we see there's increased signal at the posterior meniscal capsular junction.

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There's a lot of it, it soft tissue edema, um,

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don't see a meniscal tear. Um, and we look at the articular cartilage.

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Um,

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this thin gray strip that you see overlying the bone is your articular

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cartilage.

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So we make sure that the articular cartilage is intact all throughout, uh,

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and along the medial femoral condyle extending into the medial trochlea.

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And then the medial tibial plateau here. And, uh,

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just looking at the marrow. And then, uh,

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we can finish up the medial compartment by looking in the coronal images.

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Now we move on to coronal images. We start from anterior to posterior.

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This is the anterior horn of the medial meniscus.

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Has normal size shapeless signal intensity. That's what we need to make sure,

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uh, to exclude a meniscal tear. Looks normal.

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Looks normal. Uh, on the periphery we have lot

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Of of soft tissue edema, but let's finish up with the meniscus. Meniscus looks,

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okay. The medial compartment, articular cartilage that creates tip overline,

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the bone intact. And then we try to look for the medial collateral ligament.

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And what we see here that, um, it's,

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it's completely torn from its femoral attachment. You don't see any fibers, uh,

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coming and inserting onto the medial femoral condyle.

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And the injury is also suggested by presence of so much of soft tissue edema and

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fluid.

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So we have a complete tear of the medial collateral ligament from its femoral

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attachment. Um, and from the anatomy, uh, we know that, uh,

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medial collateral ligament has a superficial band.

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So this thick black structure that we are looking at as a superficial band.

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So this is the tear of the superficial band, of the medial, um,

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collateral ligament. And then it has, uh, deep components.

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It has a meniscal femoral component and a menial component. And, uh,

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even those deep fibers are down as well.

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Now we move on, uh, further, um,

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towards the intercon notch. On the sagittal images,

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we can now we can review the cruciate ligaments, and

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this is the anterior cruciate ligaments. Slightly higher signal,

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but no fiber disruption looks intact,

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but a lot of edema in the intercondylar notch.

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This is PCL, this black band that goes from, um,

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the femoral condyle to the posterior tibia looks intact. And, uh,

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I would recommend not just looking at these, uh,

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crochet ligaments on the sagittal images,

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but we should be able to look at them on coronal and axial images too. Um,

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um, this is really helpful, um, in,

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in chronic injuries and impartial tears. Um,

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because in sometimes in sagittal bands,

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if it's a chronic injury or it's a partial tear,

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you may get a sense that it's intact. And, um, you, you,

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the complete assessment on ACL is when you also look at it on coronal and axial

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images. So we have coronal images here.

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This is the tibial insertion of the anterior cruciate ligament.

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It has two bands. That's why we see those two hyperintense bands.

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And then there is a slight, uh, slightly higher signal between the two bands.

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That's normal. We should not miss, uh, call this as a tear.

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And we see it inserting onto the, and the,

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and the intercon notch and the femur. Similarly,

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uh, PCL, we have to follow the PCL on coronal images.

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So that's PCL inserting onto the posterior tibia,

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and we can follow, it's right there.

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And you see it inserting onto the,

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the roof of the intercon noch medial side and looks at that.

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Now we move on to the lateral compartment,

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and what we see is, um, mar edema in the lateral femoral condyle.

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Um, it's, there's a subc chondral signal. Um,

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so this is how your osteochondral impaction injuries look like. Um,

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so then we have an osteochondral impaction injury along the lateral femoral

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condyle. The lateral meniscus is looking, okay,

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that's the body of the lateral meniscus. The anterior horn, posterior horn

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looks fine. The articular cartilage,

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that craz strip of tissue here looks fine all the way to the trochlea.

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And along the tibia, same. We'll finish that on the coronal images.

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The anterior horn of the meniscus looks okay, the articular cartilage.

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I know we have this osteochondral impaction injury here,

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and the posterior hor looks okay then coming onto the lateral collateral

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ligament. Um, we know it's not just one ligament, it's a complex. So, uh,

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more, and this is your, um, iliotibial band, which comes in insert on, uh,

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onto the Go East Tubercle as we go both posteriorly, um,

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in between after the IT band is what we get the int lateral ligament,

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we don't see that ligament separately on a MI imaging,

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but a vaginal injury of the int lateral liga ligament, um,

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it's attached onto the rim of the lateral tibial Pluto.

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And that gives rise to your sigon fracture on X-rays.

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So if there's no sigon fracture on X-rays,

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we can presume that the int lateral ligament is intact. Then, uh,

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we look at the, the lateral collateral ligament proper,

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which is your fibular collateral ligament arises, uh, from the, uh,

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lateral femoral con goes and inserts onto the proximal fibula.

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And then another,

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this thick structure that inserts along with the fibular collateral ligament on

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the proximal fibula is your biceps tendon.

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That's another important constitu of lateral collateral ligament complex.

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So that's your, um, biceps tendon.

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Another important structure of lateral collateral ligament, uh,

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complex is your pletus tendon.

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So that's your pletus tendon inserting onto that popliteus hiatus along the

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lateral femoral condyle other notch. And this is your popal muscle,

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which course obliquely along the posterior aspect. So we are looking at this.

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So this is your popliteus muscle. Uh, this is your myo tendons junction,

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and you can follow the popliteus tendon entering the joint to the popal hiatus

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and inserting onto this pop notch on the lateral femoral.

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So these structures, um, look, okay, we know we have, uh,

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joint effusion just finishing up these coronal images from front to back.

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We know there is a lot of edema, um, um, and fat stranding on this side.

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We'll review these structures on axial images. Again,

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a lot of edema even along the poster medial aspect of, uh,

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of the knee on sagittal images.

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Now we move on to axial images.

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We have joint diffusion.

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The petillo femoral compartment is best evaluated on axial images.

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As we scroll down, we see the petula is, um,

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the trochlea has nice step. So, so there is no trochlea dysplasia.

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The PETULA is central, uh, setting centrally within the trochlea groove.

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So there is no lateral tilter subluxation. The articular car, uh,

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cartilage looks intact slightly more inferiorly.

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So this is the adductor tobo where the MCL inserts and along the, uh,

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anterior aspect of the medial collateral ligament. This is the MPFL, uh,

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which comes and inserts along to the anterior aspect of the adductor to bocal.

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So we can see the, um, there's a lot of thick soft tissue thickening,

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and we don't see discrete black band of the NPFL. So there's some, uh, sprain,

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uh, we don't see, um, like a full thickness there,

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but there's definitely sprain, uh, of the, uh, femoral attachment of the NPFL.

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And this is the lateral macular, which looks okay,

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the trochlear cartilage looks okay. Again, a lot of thickening, um,

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and heterogeneity here from, uh, mild MPFL injury.

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As we, uh, review this, um, um,

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the other structures that we need to review on the, uh,

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the medial sal along with, um, when we know that we have a, uh,

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like a complete tear of the medial collateral ligament as the post medial

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complex of the knee. So, um, uh, we need to know the anatomy here.

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So the post medial corner of the knee is anything that extends from the

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posterior margin of the MCL to the,

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the medial end of the posterior crucet ligament. So all the structures here. So,

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um, there's certain, um, named ligaments,

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and these are nothing but thickening of the joint capsules that provides

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additional stability to the joint. So here, um, what lives is the, uh,

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posterior oblique ligament. So we see that again, uh,

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we don't have continuity like a,

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like those black intact structures here. So there's disruption of,

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there's injury to the posterior oblique ligament.

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This is another component of the post media complex,

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is the semi renos insertion onto the proximal tibia.

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And we see that there's slightly, uh,

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like the slight thickening and increased signal. So there's injury or, uh,

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strain of the semimembranosus. Yeah,

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when you follow the joint capsule along the poster medial side,

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you have the posterior oblique ligament semimembranosus and the oblique

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popliteal ligament. So again, slight thickening and sprain. So, um,

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so we have, um, complete air of the MCL from its femoral, uh,

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attachment and then injury to the post medial complex of the knee.

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So those were the, the main findings. Here we see, uh,

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fluid along these semiosis.

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And as we scroll down,

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the other tendons that live on the medial side are sartorius gress,

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semi tendonosis. They go and insert onto the proximal medial, uh,

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tibia. And, um, that's your pest and reus insertion.

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So if we see the risk of fluid along these, um,

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pest andreus tendons right here,

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the other things to look for posteriorly is obviously you're looking at all the

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other muscles, making sure there is no, uh, additional muscle tears.

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You have to look at the neurovascular bundle.

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So that's your popal artery and vein.

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And we can see the nerves clearly here.

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So this is your tibial nerve that goes along with this posterior, uh,

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popal neurovascular bundle.

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No edema, uh, fluid or hyperintensity in the nerve. The nerve is, nerve is okay.

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And then we have, um, um,

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the common peroneal component here that starts migrating co laterally in the

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popal fossa, and then it, um,

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it goes inferiorly and will wrap around the fibular neck.

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And that's where injuries to the, uh, common peroneal nerve are most,

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that's one of the commonest site of a common peroneal nerve injury.

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So here we can see the common peronial nerve looks fine.

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Okay, to summarize, we have complete tear of the medial collateral ligament.

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We saw injury to the post medial complex,

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and we have an osteochondral impaction injury along the lateral femoral

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condyle. So an an, um, a,

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a vian injury here of the MCO from its femoral attachment,

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and then having an osteochondral impaction injury on the lateral side.

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It suggests a valgus pattern, mechanism of injury.

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So means the joint, um, the leg was pushed, uh, uh, uh,

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had a valgus force. This got stretched and pulled out. And on the, the lateral,

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uh, side of the knee was impaction,

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and that's how they got an osteochondral impaction injury. Here,

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significance of detecting post medial corner injuries along with ligament

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injuries is like, um, isolated MCL injuries are, are, uh,

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often not surgically repaired. They heal on their own.

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The joint is still stable and the athletes are still able to perform.

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But if you have post medial corner injury along with MCL,

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it makes the joint a little bit more unstable, especially in the extension,

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uh, position of the knee. And, um, so those can be surgically repaired.

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But if this, um, uh,

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if we have acute multi ligamentous injury where the MCL is torn,

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there is injury to the postel corner along with injury to the cru uh,

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cruciate ligaments, then definitely that becomes a, a surgical case.

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Those ligaments will be surgically repaired. Um,

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and the significance of detecting post medial coronary injuries on imaging is

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if, if we don't call this and the surgeon doesn't take care of this,

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the ACL or the PCL repair, that they do fail quickly or, um,

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uh, fails early because your joint is still unstable on the medial side.

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So, um,

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MCL uh, provides stability to the joint, um, um,

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and when they do their clinical test, if the MCL is completely torn,

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it'll open up on valgus force when the knee is inflection,

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but the stable when the knee is in extension.

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But if the post medial corner is torn as well, then uh,

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the knee is completely unstable. It opens up both inflection and extension.

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So that needs to be taken care of before the surgeon, uh,

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plans an isolated ACL repair or A-C-L-P-C-L repair.