Ultrasound of the Elbow - SD

Introduction to Elbow Ultrasonography

I am Dr. Tony BofA from Henry Ford Hospital in Detroit, Michigan, and tonight we're going to be talking about ultrasonography of the elbow.

It's one of the more demanded examinations for the upper extremities.

For the next 30 minutes, let me walk you through how to look at elbow ultrasonography.

Ultrasound of the elbow requires that we know its uses for this particular joint.

As you very well know, musculoskeletal ultrasonography is symptom directed and therefore we can tailor our particular examinations to the symptoms that the patient is complaining about.

Also, try to recall that ultrasound is real time imaging and therefore dynamic views or stress maneuvers can be easily employed for this modality for ultrasonography of the elbow.

Let's approach it in such a way that people come in with their symptoms and complaints and so we could look at joint fluid, whether it be infected or inflamed.

We could look at joints that lock or click.

Then after that, let's look at of course, the most common indication that at least we see in our institution, which is trauma and let's divide this into two.

First, the very universal examination of the tendons where ultrasound is probably the best modality for addressing this structure.

And then let's look at instability.

Usually what is affected in the elbow would be the ligaments.

Finally, and but not the least, we're going to look at the ulnar nerve within the cubital tunnel.

As you are very well aware, ultrasound has been becoming very popular for looking at peripheral nerves.

Effusive Joint: Infection or Inflammation

For the effusive joint which may be infected or inflammation, let's take a quick review of the elbow.

Recall that there are two major recesses, which is the anterior recess and the posterior recess.

The posterior recess is often called the olecranon fossa.

In the anterior recess there are two fossae.

First the shallower and smaller radial fossa and then the deeper and larger coronoid or coronoid fossa.

What we sometimes forget is that there are other recesses of the elbow and probably one of the more important ones is the annular recess, which is a good area to look not only for loose bodies but also the synovitis that may involve this particular lining or recess.

Likewise, on the posterior elbow there is an equally capacious recess, which is the posterior radiocapitellar or radioulnar joint wherein once again you may have some loose bodies hiding in this region.

We should try to address these recesses as often as possible during the routine exploration of the elbow.

A good example to start would be the 62-year-old gentleman who comes in with chronic elbow swelling and pain, but bilateral note that not only do you appreciate the soft tissue swelling over the posterior elbow from the distal humerus all the way around the olecranon process bilaterally, but also in the cubital region like this faintly seen here is an elevated anterior fat pad sign on both the left and right elbows.

Now while it is very difficult to appreciate what's going on on these lateral x-ray or radiographs, it is quickly seen on ultrasound that you indeed have an effusive joint case in point, you'll notice that they are near symmetrical.

First let us address the bone acoustic landmark.

Here you see the round capitellum and the flat head of the radius along with the radial neck.

And here to this you'll see that the capsule is not only distended but within the intraluminal portion of the capsule.

You'll see this intermediate echoes and thickened lining representing not only the nodular synovitis but also proliferative synovitis that's occurring with this individual.

Likewise, if you take a look at the left elbow, not only do you appreciate the same capsular distension, but this is a great and beautiful example of the tendon fluid and serum in the annular recess which occurs below the neck of the radius.

To top it all, you'll also note that there are cortical irregularities involving not only the surface of the radial head, but also it's articulating subchondral surface.

So these now clues us in that this type of changes should be chronic and should be quite inflammatory continuing.

Now we'll notice too that once we apply power doppler to this area, you'll notice the confirmation of Doppler positivity not only around the lining of the standard capsule and walls, but also well within it for this positivity in doppler and geography, both on long axis and on short axis.

Note one more time that what is usually pristine and very smooth cortex shows you some irregularity in response to the hypervascularity and the chronicity in inflammation that occurs in these individuals.

The differential diagnosis, a very short list would include hypervascular or hyperemic pannus in rheumatoid arthritis, but also in chronic infections such as tuberculosis in our case, because we are almost near epidemic for some of chronic infections, especially in a city wherein there is a lot of positive HIV and aids, this turned out to be a chronic inflammation which was tuberculosis.

On the other hand, you may get this type of patient, a younger individual who comes in with not only elbow pain and fever, but also initially negative joint aspirations.

If you look at the frontal radiograph and the lateral radiograph, you immediately appreciate the surrounding soft tissue swelling, but also note that the radiolucencies underneath the articulating surface represents subchondral changes or permeated erosive changes.

And while again try to remember about the history of fever.

In addition, if you are astute enough, you also would appreciate that there is some narrowing of the joint space.

If you add ultrasound immediately, you can appreciate that extended olecranon fossa.

And here not only do you see the fundus quite ballooned, but also well within it, you get to appreciate the fact that there is some proliferative synovia in gray scale for confirmation power.

Doppler indeed shows that this is true and that the Doppler positive angiography tells us that there is neovascularity in this individual.

So therefore, what we were seeing in this patient, aside from the radiographic clues and the history of fever was bacterial infection.

More often than not we encounter staphylococcus aureus.

Take a look at the ultrasound, which is needle guided.

Here you see the shaft of the needle, the tip of the needle as we sample it.

The high level echo with some reverberation artifact represents gas or possibly air introduced by the examiner.

As we sample this elbow, note two that with a needle we can distinguish which one to sample either the fluid part of it or we could also use a true cut needle and sample the more soft tissue or mass leg appearance of the distended olecranon fossa.

One of the things that we forget because we usually concentrate on the intraarticular portion of the elbow, is that on the paraarticular structures, you may have some bursal.

Case in point you can appreciate in this diagram the olecranon bursa note that the bursa wraps around the olecranon process and that indeed it has a distal portion to it.

This is going to be important because you have to address the olecranon bursa from the distal humerus all the way to the proximal forearm, in this case the ulna, in order to capture the structure in its entirety.

The other thing that ultrasound is going to be helping you is that you're going to gain a healthy respect for the soft tissue outline or abnormalities that you get on radiographs.

Once you begin to learn ultrasound and MRI, you begin to appreciate the fact that for example, along with this patient's complaint, you'll notice that he has a distended soft tissue outline or soft tissue swelling.

So immediately when you get to see this, you try to look underneath and then you'll notice some cortical irregularity in dispersal.

That is because the 72-year-old male has olecranon bursitis.

Here you see the bone acoustic landmark of the olecranon process, and as we go distally on the proximal portion of the ulna or ulna, you'll see that super adjacent to this is a distended relatively hypoechoic bursa.

And to add insult to injury, you'll notice that there is indeed some intermediate echoes within the intraluminal portion representing olecranon bursitis.

The pitfall that sonographers and sonologists encounter is that it's not uncommon for them to stop their examination only at the olecranon process.

Little do they know that the olecranon bursa extends distally, so you must insist that you have to explore the olecranon bursa all the way from the distal humerus to the proximal part of the ulna after the effusive joint.

Locking or Clicking Joints: Loose Bodies

One of the more common complaints about the elbow is some locking or some funny kind of clicking.

Radiographs are sometimes helpful, but you must know where to look for these loose bodies which are often the cause of clicking or locking here.

You could see in the olecranon fossa two radio opacities round and form and contour that may represent loose bodies.

Likewise, try not to forget that the annular recess is also an area that may contain some loose bodies on the lateral radiograph.

It may help you to take a peek in the anterior recess.

Note here, a subtle round opacity resting just anterior to the capitellum within the anterior recess.

The suspected radiopaque capacities on the olecranon fossa is no longer appreciated on this lateral radiograph for the confirmation of loose bodies in the elbow and in our institution also that in the ankle we often employ ultrasound because with ultrasound, immediately when you put the transducer over the areas of suspected loose bodies, you see a high level echo within an effusive fossa and along with the high level echo, depending on the size of the loose body and the footprint of your transducer, you'll notice a posterior acoustic shadowing on long axis and also on short axis, the degree of fluid in the olecranon fossa shows that distension indeed helps us outline the proliferative changes and the nodularity of the synovitis that accompanies this loose body.

Sometimes you may have very little fluid in order to outline the loose bodies, but what little there is is still very possible to indeed confirm the high level echoes.

In this case, the size does not permit much posterior acoustic shadowing a little bit on the long axis and just a tad on the short axis, but still very perceivable within this distended anterior coronoid fossa wherein you have mild elevation of the anterior fat pad.

It is not until you look at the video clips wherein now you begin to appreciate the loose bodies.

Why dynamic imaging permits us to show not only in both long axis and short axis, but we could see the mobility and the translation of the loose bodies.

Here again, with a minimally distended olecranon fossa with fluid, you see an elevated posterior fat pad sign, a high level circular echo with posterior acoustic shadowing.

Indeed confirming that you have a loose body on long axis view, long axis because you see the multipennate structure of the triceps muscle and the fibrillar pattern of the triceps tendon in the long axis view inserting on the olecranon fossa.

And if they're looking at it on the long axis view, it'll be a compression.

You again appreciate the bouncing up and down of this loose body.

Trauma: Tendons

Now it's now switch into looking at the use of elbow ultrasound with trauma, and of course we want to look at the tendons.

Probably one of the more common tendons affected is going to be the common insertion for the extensor tendon.

Here. You could appreciate on netters drawing that the extensors all become a conjoint tendon inserting into the lateral epicondyle on gray scale imaging of ultrasound.

You'll appreciate the bone acoustic landmark of the lateral epicondyle, the joint space, and then you see the radial head with a radial neck and of course one more time minimally and physiologically the extended annular recess.

Now you could also appreciate that there is a fibrillary pattern inserting on the lateral epicondyle representing the insertion or conjoint tendon of the extensors.

Around that is the relatively hypoechoic multipennate structure of the muscles when affected.

You'll notice that it's very easy to look at left right comparison of the elbow.

You already recall that there is the intact fibrillar pattern of a normal tendon inserting onto the equally pristine lateral epicondyle.

Here's the joint space and the radial head around it is the multipennate structure of muscle When diseased, what you'll get to see is first the fusiform hypoechoic swelling of the tendon lost of the fibrillar pattern.

And if you look at it carefully, not only do you see the increase in volume size, but also within the intrasubstance portions, you begin to detect hypoechoic defects representing mucoid degeneration or an evolving partial thickness tears.

So one of the advantages of ultrasound is the left right comparison.

Well, immediately you could appreciate the different changes between the affected side and the usually asymptomatic side, but try to remember that ultrasound is a tomographic modality and therefore we should look at lesions both in long axis and short axis.

So you already are familiar with the tennis elbow or lateral epicondylitis in the long axis view with fusiform hypoechoic swelling and of course loss of the fibrillar pattern of the tendon.

But in the short axis view, you want more time confirm indeed that there is enlargement of the tendon at its insertion and the hypoechogenicity that's affecting this tendon in particular.

And of course the evolving partial thickness tear or mucoid degeneration that you can appreciate not only on the short axis but also on the initial long axis.

Medial Epicondylitis (Golfer's Elbow)

Swinging ourselves through the medial aspect of the elbow, we get to meet the common insertion of the flexor tendons.

Note that the flexor tendons from the carpal tunnel area all become one conjoint tendon, a wide sheet inserting into the medial epicondyle.

If you'll permit me, I'd like to call this the trochlea.

So from the colored netter drawing, we're going to swing over to the gray scale imaging of ultrasound where you see the apex of the epitrochlea, the downsloping and ccu of the ulnar notch along with the joint space.

And finally the olecranon process above that, now you'll see some connective tissue and then the fibrillar pattern of the conjoint tendon of the flexors into the common insertion into the trochlea accompanied by the multipennate structure of its muscles.

When diseased medial epicondylitis may also be called golfer elbow.

This is what you get to see the universally stated diffuse form hypoechoic, swelling of the tendon lost of the echo signature of the fibrillar pattern.

And alongside that, you'll also see some cortical irregularity.

So depending on your slice selection, whether you're cutting it on the midpoint, you not only see an unfused heterotopic ossification or spur, but also maybe even some cortical hyperostosis and or maybe a healed avulsion fragment.

As you proceed to another slice selection a little bit more posterior, you again confirm the hyperechoic level with posterior acoustic shadowing representing the cortical irregularity that we appreciate on radiographs.

Likewise, as you go further down, you also appreciate that in the paraarticular region, the cortical irregularity has started to create some subchondral or subcortical cysts degenerative in this case.

And one more time, the hypoechogenicity of tendinosis in this individual with golfer's elbow.

Triceps Tendon Tear

Another traumatic example affecting the triceps tendon would be a case of an ER physician who continues to go out with the emergency medical technicians and practice some ambulance running that day.

They were practicing how to rappel down buildings in order to be ready to save some of their patients In an emergency situation.

You'll note that not only is there soft tissue swelling around the olecranon fossa, but also that the soft tissue swelling goes entirely around the ulna.

And if you look immediately around the cortex, you may appreciate a small and minor cortical irregularity.

Well, it's very easy to bring him over to the ultrasound, which is also equally accessible as the musculoskeletal radiologist.

And once we see it in long axis, you'll appreciate the bone acoustic landmark of the olecranon process.

You'll see that the expected fibrillar pattern of the distal triceps tendon is interrupted by this hypoechoic cleft.

Not only does it transect through the multipennate structures of the muscles surrounding the tendon at the musculotendinous junction, but also you'll get to appreciate the fact that it transects the fibrillar pattern of the tendon proper and then spills over to the virtual space of the olecranon bursa.

So now you've got a tear and a hemo bursitis accompanying this patient's complain just like we said, as expected because of the soft tissue swelling.

So triceps tendon discontinuity can be readily visualized with ultrasound.

And here in a panoramic view you see that the multipennate structure of the triceps muscle has this hypoechoic cleft running through the fibrillar pattern of the triceps tendon spilling into the olecranon fossa.

And for confirmation, and especially since we were near the MRI unit, we were able to confirm indeed that there is a separation of the triceps tendon represented by the signal void structure.

Here you could appreciate the stump of the triceps tendon, the hematoma, the same transecting hypoechoic cleft that we appreciated on ultrasound.

And of course, the hemobursitis that runs distally into the proximal portion of the ulna.

Distal Biceps Tendon

The distal biceps tendon is a little bit more challenging.

As you can see from this illustrations in the normal individual note that the distal biceps tendon dives down into the tubercle of the radius.

Not only does it dive down into the tubercle of the radius as you could see on the AP view, but note too that on the lateral view it has this very sweeping arc as it leaves the musculotendinous junction going to its way to the radial tubercle.

In ultrasound, this can be readily examined, but with a special type of maneuvers.

What we're going to see as the distal biceps tendon runs down to the radial tubercle on both the anterior and lateral view is something that we can prepare ourselves with.

Let us begin by looking at the bone acoustic landmark of the radial head radial neck going into the radial tubercle.

What you want to do now is look for the fibrillar pattern of the distal portion of the biceps tendon inserting into the radial tuberosity.

This is essential because all tears must involve the insertion of the distal biceps tendon.

This will distinguish tears from tendinosis.

When we examine these individuals in spite of the fact that they may have swelling, we ask them to hypersupinate their hand with the thumbs down and then we look for the distal biceps tendon.

Here you see the hypersupination of the hand and thumb we do a heel toe maneuver.

In order to get a 90 degree visualization of the fibrillar pattern of the tendon, sometimes you might have to direct your transducer a little bit more lateral.

Here you could see the heel toe maneuver in order to avoid anisotropy in patients with tendinosis of the distal biceps tendon.

You will again appreciate the fusiform hypoechoic swelling, but no interruption at the level of the radial tubercle.

This is the radial tubercle, and as you go more proximal, you see the radial neck and then the radial head, the joint space, and then you have the capitellum here.

You could appreciate that the fibrillar pattern now has an area of hypoechogenicity representing tendinosis.

In addition, you'll notice the accompanying brachial artery in the short axis view.

You'll notice that the fibrillar pattern of the usually normal tendon now is hypoechoic with an intrasubstance change, presumably representing mucoid degeneration or partial thickness tears.

Here is the companion brachial artery, aside from the hypoechogenicity of the tendon, what was pointed out to you earlier with a distension of the tendon sheath now shows it to be a halo surrounding the tendon for confirmation of distal biceps tendinosis.

When there is a violent rupture of the distal biceps tendon, usually in a patient with flexed elbow against forced extension, this is what you get to see.

First the bone acoustic landmark of the radial head, radial neck, and then finally radial tubercle.

As we have told you before, all tears of distal biceps tendon must occur at the insertion into the radial tubercle.

Case in point, you'll notice that you cannot find the fibrillar pattern of a tendon.

Instead here you could see the proximal stump of the distal biceps tendon.

Along with that, you see this focal hyperechoic or high level echo, representing presumably a small avulsion fragment.

And for confirmation, again orthogonal views both on long axis and short axis, you'll see the collection of fluid representing hematoma representing hematoma over the radial tuberosity.

One more time, the high level echo, presumably representing a small cortical avulsion.

Instability: Ligaments

Now let's switch over to what happens to the elbow when it's unstable.

Will address the ulnar collateral ligament, which is a commonly affected ligament in the elbow, especially for the throwing athlete.

The ulnar collateral ligament is made up of three bundles.

You have the anterior bundle and then you have the transverse bundle.

And then finally you have the posterior bundle.

We are going to be concerned with the anterior bundle of the ulnar collateral ligament.

The ligament by definition connects bone to bone.

So if you connect the epitrochlea to the coronoid fossa, then you get to see the packed fibrillar patterns of the ulnar collateral ligament.

So here's the bone acoustic landmark of the epitrochlea or medial epicondyle.

Here's the ulnar notch.

Here's the joint space between the trochlea and the coronoid process.

And if you connect the apex of the trochlea to the sublime tubercle of the coronoid process, you get to see with a bit of anisotropy, the ulnar collateral ligament.

A heel toe maneuver would've helped us to do this in order to look at the more compact or packed fibrillar pattern of the ulnar collateral ligament.

Note that we are a little bit more posterior than the conjoint tendon of the common insertion for the flexor tendon.

So we see only a part of the tendon and mostly the multipennate structure of the different muscles when affected.

The ulnar collateral ligament.

The anterior bundle, as you could see on both netters drawing and on the gray scale imaging of ultrasound.

You'll notice on interruption here one more time, the bone acoustic landmark of the epitrochlea.

As you bridge it towards the sublime tubercle of the coronoid process, you get to see a hypoechoic lesion interrupting the packed fibrillar pattern of the ulnar collateral ligament compatible with an acute tear of the ulnar collateral ligament.

As we said before, left right comparison is very helpful in order not only to convince yourself but also your referring physician.

Let's look at the unaffected right side where it have the trochlea connecting with the coronoid process.

And here you see the fibrillar pattern, especially over the joint line of the intact ulnar collateral ligament.

Above that, you see the multipennate structure of the common flexor muscles.

Once you go to the affected side, not only do you appreciate this hypoechoic collection of hematoma, the slackening of the fibrillar pattern of the ulnar collateral ligament, but you may also appreciate a small avulsion fragment of the trochlea.

In addition, note that there is increased separation or distraction between the distal portion of the trochlea and that of the coronoid process in comparison to the very tight asymptomatic joint space of the right elbow.

Ulnar Nerve in the Cubital Tunnel

In this case, let's finish by looking at the cubital tunnel of the elbow.

Within the cubital tunnel, you have the ulnar nerve, and this is often affected because this is an area of acute flexion and of course, rapid extension.

In examining or locating the ulnar nerve, all you have to do often is to bridge the trochlea onto the olecranon process For the short axis view.

Here, you could appreciate topographically the point of the trochlea along with the corner of the olecranon process.

Once you do that, you see the bone acoustic landmark of the trochlea and you jump onto the olecranon process.

Here you see the joint space between the distal humerus or the trochlea and that of the olecranon process and ulnar the follicular looking like hypoechoic structure represents the ulnar nerve short axis.

Note that it is always in proximity to the apex of the trochlea.

This location is normal.

And so this is the area we'll try to look for it at least within the proximal portion of the cubital tunnel in the short axis view In the long axis view, very simply identify the epitrochlea slide towards the olecranon process and you should be able to capture the T tram track looking like or the fascicular pattern of the ulnar nerve.

Here you could see the topographical landmark of the trochlea and almost immediately posterior to it or adjacent to it would be the ulnar nerve with its fascicular pattern.

So it's gonna be closer to the trochlea, the notch of the olecranon process.

So when you do that with a partial volume averaging a bit of the epitrochlea, you begin to see this hypoechoic, relatively hypoechoic structure.

It's relatively hypoechoic because it's well within the hypoechoic changes of the connective tissue and fat.

Note that it's got three lines.

So it does look like a rail track in this individual and extends from the supracondylar portion into the cubital tunnel proper into the distal portion of the ulna.

The diseased ulnar nerve can be appreciated in this example wherein within the cubital tunnel you have the diffuse form hypoechoic swelling of this nerve Note too that in the supracondylar portion it maintains a T track appearance as it enters the cubital tunnel and likewise the unaffected distal portion where again, it resumes its fascicular or T track pattern.

But it's not until you look at it on short axis view in left right comparison that you begin to appreciate the fact that there's indeed a great change between the unaffected right side with a smaller size and probably a twofold increase in its size.

And the affected nerve notice too that the fascicular pattern is more markedly hypoechoic and amorphous in the affected left elbow.

One of the things that we always continue exploring is going to be ulnar nerve subluxation.

Although 10 to 16% of individuals would have a normally subluxing nerve, some of them may become indeed abnormal.

And the way to explore it is you wanna park the elbow over the edge of the table.

You can might have to bolster it with some additional sheets and ask the patient to extend and flex, and I should do that.

On short axis view, it was expected that the relatively hypoechoic fascicular pattern of short axis view of the ulnar nerve is supposed to stay behind the trochlea.

In the affected side, you'll notice that the follicular looking alike structure, which is the ulnar nerve, sublux and dislocates from the posterior position to the anterior position.

And if you can continue to hyperflex the individual, you might even get to see the snapping triceps syndrome wherein not only does the ulnar nerve sublux when you extend, but that the triceps muscle itself may indeed contribute to its subluxation and dislocation, but pushing it out of the cubital tunnel.

Conclusion

Well, I hope in the last half hour I was able to show you the indications of ultrasound in the elbow.

Note that effusion and synovitis is readily visualized in the elbow and those high level echoes that may be mobile are indeed loose bodies for tendon disease.

Then nothing can beat musculoskeletal ultrasonography as you have appreciated, at least in this elbow lecture.

In addition, because of the echo signature, which appears to be also equally fibrillar in ligaments, it is also indeed very useful to use ultrasound because we can detect and locate lesions involving the ligaments.

And along with dynamic imaging, we have shown you that you could see the separation of the joint space and or the maneuvers that can exaggerate the separation of the bony structures.

Last but not least, we get to see that one more example of peripheral nerve neuropathy, which is the ulnar nerve within the cubital tunnel.

So with this, I'd like to thank you so much for your attention.