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This is a 57 year old man

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with medial left knee pain. The knee gives out,

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it swells. It's been going on for two weeks.

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Had a history of a twisting injury and arthroscopy three years ago,

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not three days ago, three years ago.

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So to be transparent,

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I like to start my knees because I tend to see a lot of middle-aged and younger

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individuals. Yes, I do see a lot of older people with arthritis,

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but I like to look at the patella femoral architecture right away because

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everybody has an abnormal patella.

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And I wanna figure out how much contribution to the patient's clinical

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pain syndrome is the patella cuz that will color the rest of my report

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and the rest of my search pattern.

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And the answer is in this patient who's,

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let's see, 57 years old, not bad. I bet

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cartilage looks pretty good. There's not a lot of patella dysplasia,

1:04

there's not a lot of trulear dysplasia.

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There's a lot of messy signal anteriorly,

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some heterogeneous signal with some synovial Frans maybe,

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but I don't think the primary problem is in the patella.

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Let's put up a coronal and scroll that.

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Let's put up the sagittal pd, fat suppression and scroll that.

1:35

Hmm. PCL twisting injury, maybe

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PCL twisting injury. Maybe M C L.

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Maybe. Let's put up the sagittal t1.

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That's volume averaging of adjacent fatty tissue that is not in the joint.

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Hard to tell that unless you had the time to make that assessment.

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The menisci for age 57.

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Pretty good search pattern.

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I personally use an empiric search pattern now,

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but in the beginning I went by quadrant as it got more sophisticated,

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I went by tissue,

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then IED my tissues just like I did with the

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elbow and the ankle.

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And now I do it just by looking at structures that I've seen so long for over a

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quarter of a century.

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But there's no shame in going through a very systematic approach. A C L P.

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C L L C M C L P O L O P L

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post medial corner postal lateral corner. Oblique papa ligament,

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qit ligament, lateral oblique ligament of the fibula. Yeah,

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I'm raffling them off cuz there are so many. And your library, again,

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will expand and expand and expand as you get more comfortable and sophisticated

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in this genre.

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So let's take on our last question.

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What's the most likely diagnosis?

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A diffuse pigmented villa nodular synovitis. B,

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multifocal pigmented vilan, nodular synovitis.

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C intraarticular giant cell tumor of 10 and sheath.

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D, gout. E, synovial,

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metaplasia and kosis. Okay,

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most of you said synovial, metaplasia or kosis.

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The correct answer is D, gout.

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Now why isn't synovial metaplasia or osis? The answer?

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Well, how do you explain the signal in the posterior cruciate ligament?

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The high signal in the posterior cruciate ligament?

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Are you gonna postulate two diagnoses,

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a PCL tear that happened three years ago and now the patient has

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synovial metaplasia.

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I like to wrap it up into one neat box or bow.

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How are you going to explain the swelling and enlargement of the polit

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hiatus?

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That doesn't go well at all with synovial chondro mitosis.

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How are you going to explain this?

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Tumor effecti intermediate signal intensity that has infiltrated

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the medial capsule and M C L synovial cond mitosis

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isn't gonna do that. Now synovial cond mitosis can be OSUs.

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You can have corticated fragments.

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You can have fragments of cartilage that are light gray that are also round

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or sometimes they're a little bit faceted. But this is ill-defined.

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It's Infiltrative sos, the PCL SOS the papa hiatus.

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What about giant cell tumor of tendon sheet intraarticular?

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What about multifocal or unifocal Pvns?

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There should be blood as in the movie there will be blood,

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but there isn't blood. Let's take a look at the T1 weighted image.

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There's no blood. There might be a little bit of fat brewing inside,

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so I might give you a little bit of metaplasia, but there's no blood.

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This is all volume averaged fat here and there's no cerotic change.

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Even though I didn't give you a gradient echo.

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There's absolutely nothing to suggest a cerotic process as in PV n s

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multifocal or unifocal or the same disease intraarticular giant cell tumor of

5:34

tendon sheath, which is focal PBN S.

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So when you have a middle-aged individual and you've got masses inside the

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joint, like that one wrong shape for synovial kosis,

5:47

it looks like a little boulder, irregular, not round, not faceted,

5:51

not cartilage, not bone.

5:53

Middle-aged man infiltrating M C L infiltrating PCL L.

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Not in this case,

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but very often it will infiltrate the quadriceps tendon and aru the patella.

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Definitely in this case it'll get lumpy and bumpy in the papal hiatus.

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You think Gout. Any questions on this case? Okay,

6:13

what are the MRI signs of healing?

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I'm assuming you mean in bone and um,

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I'm sure most of you are more comfortable looking at CT for bridging bone

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to see medullary bone,

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to medullary bone interfaces and you'd be right. CT is is better at that.

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When bones heal on, they frequently do so with dark scars.

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But you will see if you go to the edges where the cortex is and the

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subcortical medullary bone, you'll see confluence there. Also,

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if somebody has a malor non-union,

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there's going to be high signal at the interface.

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And typically because there's motion,

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you're gonna see something that looks like this. You're gonna see an interface.

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And then at that interface you're gonna see these little cystic fosil like in

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the osteochondritis decans case. And if it's a complete non-union,

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then the area's gonna get awfully white looking in the middle.

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You're gonna have fluid signal in between.

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You'll also have swelling in the area. But bridging bone,

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when you're assessing it on mri, you wanna look at the medullary bone,

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you wanna look at the cortical bone, you wanna look for cysts,

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you wanna look at the character of the bone.

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Is the character of the bone the same as more normal bone further away from the

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fracture site? But admittedly,

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it's easier on CT to evaluate bridging than it is on mri.

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Are there any other questions?

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Can you speak about subcutaneous edema anterior to the mid patellar tendon as

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opposed to pre patella bursitis or superficial infra patella bursitis?

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Call it a adventitial bursitis. So that's a,

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that's a really important question actually,

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and let me see if I can call up the sagittal.

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One of the most commonly overlooked diagnoses is pre patella

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plate injury.

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So many times people with swelling here it is called inadvertently,

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or perhaps due to lack of experience, it is called pre patella bursitis.

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Now you do secondarily get bursitis here from a number of reasons.

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You could get it from kneeling,

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you could get it from an inflammatory process including gout.

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Gout loves this area, gout loves this area.

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Gout loves to erode the superior patellar.

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But another common cause of swelling here is individuals that have injured the

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pre patella plate. So what is the pre patella plate? Just quickly?

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I know we're short on time. So when the quadriceps comes down,

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the rectus femoral forms, the outer layer,

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it continues over top of the patella as an area of

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fascial tissue and then forms the patella tendon. This plate is made up of,

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depending upon who you read, four or five layers. When it's swollen,

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you can see at least four of the layers and between those layers are various

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bursa. So it's even more complicated than what you've inferred.

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You can have a superficial amid or a deep pre patella bursitis

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because it's such a layered structure,

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but you can also have a primary injury of the pre patellar plate

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causing a secondary bursitis. So we'll talk more about that if you wish,

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uh, at another time when we do live cases. But it's an excellent question.

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It comes up very often and what I'm describing to you is a not uncommon injury.

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Great. Thank you to all my colleagues for listening around the world.

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Very enjoyable to be with you today. Be safe.