0:00

Now there are other things that occur, okay?

0:04

Tendons may be infiltrated, and one of the structures

0:09

or diseases that can do that is amyloid.

0:12

I've been impressed through the years that amyloid can lead

0:16

to infiltration of tendons

0:17

and even beyond that infiltration of joint capsules,

0:21

particularly involving the hip capsule.

0:24

But here I'm showing you tendonous infiltration

0:27

and tendon tearing related to amyloidosis.

0:31

In a person with chronic renal failure,

0:37

there's another disorder that in fact can lead

0:40

to infiltration of tendons and that is gout.

0:44

Now, I've seen a number of examples of this

0:46

where the tendon itself is infiltrated.

0:49

The nearby bursa may also be involved.

0:53

The gouty tophi when extensive can look somewhat radio dense

0:56

and they may calcify.

0:58

So you can see that here we can use CT

1:01

or dual energy CT to better observe that,

1:04

but look at the tendon, low signal thick.

1:08

All right. As you can appreciate here, this is gout

1:12

with infiltration, probably both of the tendon

1:15

and of the versa.

1:17

So crystal deposition may occur within the rotator cuff

1:21

tendons and in tendons elsewhere.

1:25

This brings us to the subject of tendon calcification.

1:31

So let's spend a few minutes talking about

1:34

tendon calcification.

1:36

There are two main crystals that lead

1:40

to tendon calcification.

1:42

They're both commonly do, so you're aware of one that's

1:46

that's basic calcium phosphate, you tend

1:49

to call it calcium hydroxyapatite.

1:51

But other forms of basic calcium

1:54

phosphate may be the causative crystal.

1:57

That certainly is a cause of tendon calcification.

2:01

And the most common site we see,

2:03

and we'll be talking about in the next few slides,

2:05

the rotator cuff tendons.

2:08

But the second crystal, which is equally

2:11

frequent in tendons, especially in the elderly,

2:13

is pyrophosphate.

2:16

And I show you to that on the left,

2:18

and I can tell you from having studied it, typically

2:22

with pyrophosphate crystal deposition, the calcifications

2:26

can be single or multi-layered, and they tend to be linear

2:31

and they extend for a longer distance within the tendon.

2:35

With calcium hydroxyapatite

2:37

and related calcium phosphate crystals,

2:41

often they are OID in shape, at least initially.

2:45

They may be well-defined as shown here,

2:49

or they may be ill-defined when they are well-defined

2:53

and present within the tendon, they are often asymptomatic,

2:58

right when they are ill-defined

3:01

and in attendant they may be symptomatic.

3:04

The general rule that we look for with regard

3:06

to the rotator cuff tendons, the typical site

3:09

of calcification is at

3:12

or near the footprint with one exception,

3:15

which I'll mention in a moment just to show you

3:20

that particular rule in action.

3:23

Here we see tendon calcification in the supraspinatus here,

3:29

long head of the biceps in the in infraspinatus

3:32

and Tess Minor, and even in the long head of the triceps,

3:36

all at and near the footprint.

3:39

All right? The one exception to the rule

3:43

is indeed the biceps tendon,

3:45

because in a significant number of cases,

3:49

although you may see it up near the

3:50

footprint, is the long head.

3:53

You may also see it along the humeral shaft

3:56

at the myotendinous junction involving that,

4:01

uh, biceps.

4:02

So that is the one exception to the rule.

4:07

Now, as I said,

4:09

well-defined calcification within a tendon,

4:13

maybe asymptomatic,

4:15

but what becomes symptomatic is when the calcification

4:19

moves, there are three basic directions in which

4:23

that calcification may move.

4:25

The first of these, let's call superficial,

4:28

it may extend from the tendon beneath the floor

4:32

of the subacromial subdeltoid versa, or within the versa.

4:37

Here's an example that I'm showing you here,

4:39

where there was calcification actually mainly in the

4:43

supraspinatus, but also in the subscapularis,

4:46

and it is now extruded into

4:49

the subacromial subdeltoid bursa with bursitis.

4:53

So this indeed may be symptomatic.

4:58

The second direction in which the calcification may displace

5:03

is inferiorly in the bone.

5:06

I've seen this most commonly involving the greater

5:08

tuberosity, but it may extend into the lesser tuberosity.

5:13

When you look at the images, if you look at them quickly,

5:17

you're gonna say, gee, there's something in the bone.

5:19

Uh, maybe it's an osteo, osteo or something of that sort.

5:23

So the key to diagnosis is to find the calcification that is

5:27

outside of the bone.

5:29

So here we have intra osseous penetration

5:33

with marrow edema and bursitis.

5:37

Here's another example. Same sort of of findings.

5:42

You can see the calcium both outside and within the bone,

5:45

and the degree of marrow edema.

5:47

So this pattern of displacement also may be symptomatic.

5:53

And then the third direction is

5:56

Medially.

5:57

And to extend medially into the tendon

6:00

and perhaps reach the myo tendonous junction, there has

6:04

to be tearing of that tendon.

6:05

Typically, it's a delaminated tear. Now what comes first?

6:10

Does the calcium produce the tear

6:13

or does the tear allow the calcium to migrate?

6:17

I don't know the answer to that,

6:19

but I do know this can be painful.

6:21

I look at the muscle edema we see in the bottom image on

6:25

your left, certainly symptomatic inflammatory

6:29

changes within the muscle.

6:31

I've seen this most commonly within the supraspinatus.

6:34

Next, the in infraspinatus,

6:36

but also in the subscapularis as shown here.

6:40

Here we have medial migration of the calcium shown

6:44

by the yellow arrows in a delaminated tear involving

6:49

the subscapularis tendon.