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<v ->Let's move on now in the last five or 10 minutes

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and talk about a few other topics just briefly.

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And we'll talk about intraarticular bodies.

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Any process that leads to disintegration

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of the articular surface

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that can produce an intraarticular body.

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The bodies are typically composed of cartilage alone,

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or cartilage and bone together.

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Very rarely, they consist only a bone.

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The bodies can remain at their site of origin,

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or you begin to see displacement of them as in this diagram.

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They may become free or loose.

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So if you're using the term loose body,

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you better be certain it is free within the joint,

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and not embedded within the synovial membrane.

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In the old days, we did this using fluoroscopy.

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We'd palpate the joint

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to see if we could get the body to move,

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because you see what happens over a period of time,

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the bodies first will seek out recesses,

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but they then become embedded in a synovial membrane,

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evoking a focal synovitis.

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Now, there are many articular processes

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that are characterized by one or more bodies.

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Perhaps the one that's best known

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is neuropathic osteoarthropathy.

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We're gonna talk more out that later on, not today,

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but neuropathic osteoarthropathy,

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a number of diseases do this:

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Bone fragmentation is characteristic in the upper extremity

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especially in the area of the cervical spine,

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shoulder, or elbow.

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Here, the elbow syringomyelia is a good choice.

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Here's another example of neuropathic changes.

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This is a syndrome.

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There's actually several syndromes

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of congenital insensitivity to pain.

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This can lead to trauma without the patient recognizing.

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It had all kinds of bizarre fractures.

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This is a bizarre osteochondral fracture,

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bizarre evulsion fractures can occur,

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fragmentation is characteristic.

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And even in rheumatoid arthritis,

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one can see bone fragments.

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Here you can appreciate them

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in a femoral tibial compartment.

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So what happens to these bodies

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as they are thrown out into the joint cavity?

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Well, they may grow as they extend into the joint cavity

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because you see the synovial fluid can nourish them,

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but the synovial fluid effectively nourishes cartilage.

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So, although the cartilage may grow or stay stable,

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and here the yellow arrow is pointing to the cartilage,

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the bone is not nourished well if the body is free or loose.

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So, it's not uncommon to see viable cartilage

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and necrotic bone within the loose body as shown here.

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And if the body is only bone, complete necrosis may occur.

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Characteristic places that we see bodies about the elbow

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are in those three fossa.

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I talked about coronoid, radial, and the olecranon fossa.

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Here, a body, I showed you this case yesterday

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because of the thickened capsular folds that were present

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in the posterior aspect of this elbow.

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Now, one of the diagnostic challenges that we have

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relates to the ankle.

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It's not uncommon to see bone fragments

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adjacent to the medial or lateral malleolus.

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Here, I'm showing you two examples of fragments

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related to the medial malleolus,

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but only in one of them is there an intraarticular body

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because you see these are old evulsion fragments

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related to portions of the deltoid ligament.

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And they look like intraarticular bodies,

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but at the time of arthroscopy,

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the capsule may look deformed,

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but they're not gonna find a body.

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This is a body that is actually present within the joint.

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Deep to the deltoid ligament.

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It's an old image.

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It's not pretty,

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but in any case, it's not always easy

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to tell bone fragments within ligaments

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from bodies within the joint lumen

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embedded probably within the synovial membrane.

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These bodies can move around the joint,

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so you've gotta look at all the recesses.

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Here are some recesses in Hoffa's fat pad,

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a large body is seen.

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Here's an interesting body,

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which is deep to the semimembranosus muscle

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and tendonous attachments.

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It's in a patient who had severe OA,

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where they were gonna do a total knee arthroplasty

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because of pain.

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It turned out the cause of the pain was this body.

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There were certainly cartilage abnormalities,

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but this body was removed.

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And this patient did well for about a year

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before then requiring a total knee arthroplasty.

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The bodies may pass into a communicating popliteal cyst.

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Now this is interesting

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because they rarely pass back into the joint.

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So, orthopedic surgeons dealing with surgery of the knee,

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if the bodies are localized back here,

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they may not do anything with them

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because they're not concerned

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they're gonna go back into the joint.

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Now, sometimes the bodies will in fact be of the same size

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in composition as chondral defect,

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but other times because they can grow or resorb,

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that is not the case.

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In this case, we can see a traumatic osteochondral injury

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with a chondral defect and marrow change.

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And you can see the body consisting of cartilage and bone

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fits that particular defect quite nicely.

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One of the interesting things that are somewhat unique

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about bodies occur within the lateral talar dome.

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I'm gonna have you look at that a moment.

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As you look at it,

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the interesting thing is that that body

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is inverted 180 degrees,

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and that is something that occurs not only in this location,

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but typically in this location.

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So you've gotta check, is the bone pointing up or down?

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Has this rotated 180 degrees?

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And if so, it requires surgery to rotate it back

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into its normal position.

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And I'll show you another case.

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Same thing, lateral talar dome.

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This has rotated 180 degrees.

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So, this is the subchondral bone plate.

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Here's the rest of it,

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and here's the subchondral bone located above it.

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So be aware of these inverted fragments.

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Intraarticular bodies when they are multiple

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can simulate another condition we'll be talking about

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during this course;

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primary or idiopathic synovial osteochondromatosis.

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To tell the two apart,

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I can tell you when the bodies are secondary

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to an underlying joint disease.

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Here, it's osteoarthrosis.

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They are fewer in number.

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They are variable in size.

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They have a less widespread distribution,

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and you can see a problem in the underlying joint.

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When we talk about primary synovial osteochondromatosis,

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those characteristics are not present.

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And there's another condition that can fool you.

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And that's the condition of secondary lipoma arborescens.

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Now I'm gonna talk about primary lipoma arborescens

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in a later lecture.

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But when you have an underlying disease,

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and particularly osteoarthrosis as shown here,

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or rheumatoid arthritis,

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what can occur is a metaplasia of the synovial lining

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into fat.

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And so as you look at this particular example,

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there's fat everywhere, but these are not bodies.

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These are fatty deposits within the synovial membrane,

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and they are often multiple and very prominent

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and cause diagnostic difficulty.

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And then finally there are some things

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that look like bodies and are not.

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And this is one of the characteristic,

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ones that has been described.

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This is known as a meniscal ossicle.

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Now, when I learned about a meniscal ossicle,

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I learned it was developmental,

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it was seen in the posterior horn of the medial meniscus

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as shown here,

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it was triangular or circular as shown here,

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and it was found in other animals

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particularly large cats like tigers and lions,

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and occasionally in large dogs as well.

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Well, now I've learned that more often than not,

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as in this case and in the next case I'm gonna show you,

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these are not developmental,

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but what rather, they are acquired.

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And what they are related to are problems

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with the posterior root ligament of the medial meniscus.

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In some cases that root ligament pulls off an ossicle

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as seems to have occurred in this case,

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and in other cases,

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there's a posterior root ligament evulsion,

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and secondary heterotopic ossification

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later develops in the injured ligament.

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So be aware, I think in many of these cases,

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these are acquired and not developmental.