Ultrasonography of the Ankle - SD

Introduction

Hi, I'm Dr. Tony Bfa. I'm from Henry Ford Hospital in Detroit, Michigan.

We have covered several musculoskeletal ultrasound examinations tonight.

Why don't we look at ultrasonography of the ankle?

For the next half hour, why don't you come along with me and let me take you through musculoskeletal ultrasonography of one of the more important joints of the lower extremity.

Let's take a look at the ankle. Let's begin.

Ultrasound of the Foot and Ankle

For the ultrasound of the foot and ankle, it probably is best to remember that we're going to be meeting a lot of peaks and valleys and you'll have to be pretty generous with gel, especially when you go around the curving parts of the posterior tibial tendon and the opposite peroneal tendons.

Here you could see our fellow, Dr. Suman Kim, examining the medial part of the right ankle of a patient and again, hand position.

And of course, generous amount of gel would be very helpful because of the peaks and valleys of the ankle.

Like most ultrasound of any joint, we're going to be addressing tendons, ligaments.

After that we're going to take a peek of what essentially is going to be a ligament, which is the osis of the plantar fascia.

You already have appreciated the fact that ultrasound is excellent for peripheral nerves and we're going to meet another nerve within the tarsal tunnel.

We're going to end this lecture by looking at some masses that can be readily examined with ultrasound.

As far as complaints of the foot and ankle are going to be concerned.

We can approach the ankle by taking a look at it and in four regions and of course you meet the patient, you like to look at the anterior ankle first.

The important structures to remember here would be the anterior tibial tendon, the anterior recess with its synovial lining and the anterior inferior tibial fibular ligament.

From there we can take a look at the very important medial ankle and meet the three tendons that are responsible for the arch of the foot.

The three tendons are the posterior tibial tendon, the flexor digitorum, and the flexor hallucis longus also in the medial part of the ankle is a very important ligament, which is the deltoid ligament with the three components, an anterior bundle, a middle bundle, and a posterior bundle.

And from the medial ankle, let's now proceed to the lateral ankle where you'll meet the pair of the peroneus longus and the peroneus brevis again both start behind the fibula and go underneath it underneath the peroneal retinaculum.

And then the brevis will insert at the base of the fifth metatarsal while the longus goes through the peroneal groove of the cuboid and inserts on the base of the metatarsals, also on the lateral ankle.

All important and the most commonly torn ligament in the United States, which is going to be the anterior talofibular ligament.

Again, it's a ligament so it connects bone to bone from fibula to the neck of the talus.

The posterior region of the ankle probably is where most of you will begin to get initiated into musculoskeletal ultrasonography because it has the tendon, the Achilles tendon has its insertion on the posterior calcaneus and in front of it would be a retrocalcaneal bursa, which allows the very smooth flexion and extension of the tendon against the bony calcaneus.

As you go around the horn of the posterior calcaneus, you'll now come to the plantar fascia, which takes origin over the plantar tubercle of the calcaneus and inserts like a fan onto the subcondylar portions of the metatarsals.

The Achilles Tendon

So since we're all already on the posterior part of the ankle, why don't we take a look at the all important Achilles tendon?

The Achilles tendon is an aponeurosis that is formed into a cordlike structure by the medial and lateral heads of the gastrocnemius along with the soleus and fans out like an aponeurosis becomes a cord structure inserting into the dorsal tubercle of the calcaneus.

On gray scale imaging, you'll notice that in a panoramic view.

First let's go backwards because we do have to identify the bone acoustic landmark of the calcaneus.

From there you'll see the distal insertion of the fibrillary pattern of the Achilles tendon and then it meets the multipennate structure of the soleus and all the way down very little here you see the multipennate structure of the gastrocnemius in front of the Achilles tendon is the hyperechoic fat pad of Kager or Kager fat pad, also known as the pre Achilles fat pad.

And then in front of that you'll have the multipennate structure of the flexor hallucis longus.

Very important now is also the bone acoustic landmarks of the posterior malleolus.

Here you can appreciate not only the posterior dome of the talus but also the posterior talar process in the long axis view.

You'll get to see that the fibrillar pattern of the distal Achilles tendon is exclusively seen as a fibrillar pattern on gray scale imaging.

Note too that in front of it is the triangle of Kager fat pad and the two bone acoustic landmarks, which is the, not only the calcaneus but also the posterior malleolus.

Here again, you see the multipennate structure of the flexor hallucis longus ultrasound is a tomographic modality and after seeing it on long axis view, you must also see it on short axis view.

Here you get to appreciate that reniform contour of the short axis view of the Achilles tendon, usually at the level of the posterior malleolus and its hyperechoic bristle pattern in comparison to the fibrillary pattern on long axis views when diseased, most of the lesions do occur at the area of or at the level of the posterior malleolus.

It is said that this is the watershed area of the Achilles tendon, but it also said that this is an area of high torque and so therefore most of the stresses and trauma should occur at this level.

So here you could see on a universal drawing there is fusiform enlargement of the Achilles tendon at the level of the posterior malleolus and an ultrasound.

You get to see again loss of the usual echo signature fibrillar pattern of the tendon in its place to see this hypoechogenicity confirming indeed fusiform hypoechoic swelling of the Achilles tendon at the level of the posterior malleolus just beyond the multipennate structure of the muscular soleus.

We told you that aside from long axis views, as you could see on this panoramic view, you must also try to not only apply the Doppler angiography for confirmation of the neovascular or inflammation that occurs in this individual, but also in the short axis view for confirmation of the localization of the disease.

And here you see that the reniform contour has been lost.

Instead you have this oval hypoechoic swelling of the Achilles tendon at the level of the posterior malleolus.

Jack Gio is a technologist in Toronto and we share cases as we also give usually lectures in the North American musculoskeletal ultrasound courses usually in Toronto.

Aside from long axis short axis views, we also could do some dynamic imaging and of course employ power color Doppler angiography.

Here for example, we see the fusiform hypoechoic swelling of the Achilles tendon.

And above that you could see a distended vein.

The inter fibrillar distances are increased as appreciated by the hypoechogenicity between the hypoechoic fibers.

And as you go up now you get to meet the multipennate structure of the soleus.

Going back down again in long axis view confirmation of the hypoechoic fusiform swelling where all the neovascularity occur in this individual and of course the tapering back to the normal fibrillar pattern as it inserts on the calcaneus.

Swinging to the short axis view, we started with a uniform contour and then the affected size shows the hypoechoic swelling of the entire Achilles tendon.

And as we go further up, the aponeurosis of the Achilles tendon meets the tight pattern of soleus power.

Doppler angiography shows indeed the positivity of neovascularity that's occurring in this individual note that not only do you have all the neovascularity occurring within the tendon, but also along its border and of course the feeder vessels coming in from Kager fat.

So again, you could appreciate the floral pattern, the extraneous supply of the neovascularity in this individual for confirmation.

It is not uncommon that we do spectral display in order to confirm indeed that we're not looking at artifacts but true vessels arising in the affected Achilles tendon.

Most tendons have a loose tendon sheath like the long head of the biceps tendon and the posterior tibial tendon Achilles tendon has a very adherent tendon sheath known as the paratenon.

And here in the long axis view you see the examples of what's happening to an individual with a mild form of intrasubstance edema, but a fusiform hypoechoic distension or if not thickening of the paratenon on the long view of the long shaft of the Achilles tendon.

And once you have the increase edema within this individual, the incidence of the sound waves increases and accentuates the hyperechogenicity of Kager fat adjacent to the Achilles tendon.

And for immediate quick comparison, you could see that the paratenon is imperceptible in the unaffected side and from there you must also again from the long axis view confirm the short axis view.

The paratenon is a sheet that invests usually around the tendon, but it's not uncommon that it's eccentrically affected usually on the more superficial portion of it.

Note again that the reniform contour of the Achilles tendon is almost lost in this Achilles tendinosis.

But along with accompanying paratendinosis for Achilles tendon rupture, you'll notice a soft tissue swelling on the lateral radiograph at the level of the posterior malleolus.

And not only that, but you also appreciate the obscuration of the usually hyper Kager fat on the radiographs on ultrasound, you'll readily appreciate the loss of the fibrillar pattern of the Achilles tendon and then you can identify the distal stump from the proximal stump and an intervening hypoechoic hematoma in between these two stumps.

In addition, you'll also appreciate the hyperechoic Kager fat insinuating into the gap between the distal and proximal stumps.

On short axis view, you would have had the loss of the reniform contour of the Achilles tendon with its usual bristle pattern.

Instead you have this huge massive distension also of the peritenon itself.

And in addition to that you'll see the intrasubstance hypoechoic clefts of the tear.

Not to forget too, as we've seen on the long axis view, is insinuation of Kager fat into the gap between these two tendon stumps.

In a panoramic view, we have to appreciate the fact that there is a slackening of the usual taut Achilles tendon.

We have an interruption of the fibrillar pattern at the level of the posterior malleolus and in addition, you begin to appreciate the distal from the proximal stumps of the tendon rupture.

We have hammered away that once you have a vacuum and between the two stumps, then Kagers fat begins to insinuate into that area.

It's one of the parameters that we do indeed report that is because if Kagers fat is not evacuated then there's no way for the two stumps to coapt and heal spontaneously.

So one of the tests that we do is going to ask the patient to do dorsiflexion and plantar flexion in dorsiflexion.

We may be able to distract the two stumps further apart and we get to see if Kager fat spontaneously herniates out or normalizes when you do plantar flexion and dorsiflexion note again that it's indeed at the level of the posterior malleolus.

In addition, this maneuver helps us determine how far apart the two stumps of the tendons are.

Retrocalcaneal Bursitis

One of the things that ultrasound has been very helpful is to look at the adjacent structures of tendons and case in point would be the bursae that accompany them and the posterior ankle will appreciate that.

The Achilles tendon on MRI has a high intensity abnormality in front of it, representing a retrocalcaneal bursitis on MR and the sagittal T two image.

You'll appreciate that it is hyperintense but homogenous when given some contrast gadolinium in a T one sequence with fat saturation.

The same distended retrocalcaneal bursitis shows a central core of signal void representing the unaffected synovium.

Clearly.

Therefore, what we were seeing on T two was mostly the increased signal changes of edema affecting the synovitis and with gadolinium we now subtract the fluid from the synovia that is affected also, we begin to appreciate that they were subcutaneous edema in this individual.

Note that the signal void structure representing the Achilles tendon inserting on the calcaneus is quite intact.

But wouldn't it be simpler if we could look at it with ultrasound?

An ultrasound? Not only do we appreciate the fact that there is an abnormal distension of the retrocalcaneal sac, but the intermediate echoes forming or rind around the retrocalcaneal bursa represents the thickened synovitis for confirmation application of color.

Doppler indeed shows you the positivity and the positive angiography tells us that this is neo vasculature.

Now we can also appreciate that there is hypoechogenicity of the tendon, but the difference now between the MRI and the ultrasound is look how exquisite we've shown that there is early cortical changes involving this individual with spondyloarthropathy.

Those are the long axis views in the short axis views or axial views.

First on MR first, you'll notice that on T one morphologically that the Achilles tendon appears to be intact and the decrease signal in front of it represents the retrocalcaneal bursa, both synovia and fluid.

For the more fluid sensitive T two on axial imaging.

Now you begin to confirm not only the increase intensity rep of affecting the retrocalcaneal bursa for all the inflammatory changes but also surrounding the peritenon of the Achilles tendon.

The application of gadolinium on T one fat sat confirms that indeed there was a rind of synovitis affecting this retrocalcaneal bursa but the rest of the signal void represents unaffected or at least unimpeded fluid.

Here you begin to see on a short axis view of the ultrasound.

First the continued maintenance of a reniform shape of the Achilles tendon albeit with mild hypoechogenicity representing accompanying but minimal tendonitis in front of it.

Now you get to see clearly that not only is the retrocalcaneal bursa distended but there is accompanying rind of synovitis and unaffected fluid or at least spared areas where fluid is present.

And with color Doppler angiography you begin to confirm indeed the surrounding rind of synovitis with vascularity and a pool of fluid.

And this helps us because now we could see the severity of the synovitis but also if we need to sample either the soft tissue of synovitis or the fluid amount of fluid.

The Plantar Fascia

Let's go around the Achilles tendon and look at the plantar fascia.

Here you could see in a form of fan it originates from the plantar aspect of the calcaneus going into the subcapital areas of the metatarsals.

This aponeurosis tapers approximately onto the calcaneus and this is where most of the abnormalities would occur.

So on long axis view you get to see a packed fibrillar pattern of the aponeurosis inserting on the normal cortical surface of the plantar calcaneus.

Well also on short axis view, you begin to appreciate the packed fibrillar pattern of the plantar fascia as it approaches the cortex of the plantar tubercle of the calcaneus when affected just like tendons and other ligaments, you'll see this fusiform hypoechoic enlargement of the plantar fascia at the proximal origin of this aponeurosis.

In addition, you'll even see some further coalescence of hypoechogenicity which may represent some partial tears if you correctly remembered that the cortical contour of the normal and unaffected plantar calcaneus was relatively preserved.

In this one you could see that there's an overhanging spur with posterior acoustic shadowing and if you look at the short axis view, what is expected to be hyperechoic packed bristle pattern, you'll see it as very hyperechoic and enlarged with early cortical irregularities affecting the adjacent cortex of the plantar calcaneus.

In a splitscreen view, note the overhanging hyperechoic spur and the posterior acoustic shadowing on the downsloping part of the plantar calcaneus leaving the posterior ankle.

The Medial Ankle

Let's look at the medial ankle where there are the trio of the posterior tibial tendon, the flexor digitorum longus and the flexor hallucis longus.

The mnemonic that we've kept in mind, thanks to John Louis from Toronto is going to be Tom, Dick and Harry.

Dr. John Louis from Toronto said that, well, aside from the tendons, you do have the tarsal tunnel and within the tarsal tunnel you have the posterior tibial artery, the vein and the nerve.

So therefore the mnemonic has changed from Tom, Dick and Harry to Tom Dick and a very nervous Harry.

Dr. Dehi Lee from Texas points out that there are two veins and one artery, so therefore his mnemonic is a little bit longer, which is Tom dick and a very, very nervous Harry.

So T for tibialis, D for digitorum, A for artery, V for vein, N for nerve, and finally H for Harry or flexor hallucis longus.

The tarsal tunnel accompanies these three tendons and the flexor retinaculum, which is very thin fascia forms the roof.

The floor now is made of solid material which going to be the medial aspect of the talus, the bony sustentaculum tali and of course the medial wall of the calcaneus.

You already know the contents as you can read here on the slide.

And of course this is a fibrous canal much like the carpal tunnel.

If you dissect the tarsal tunnel and remove the tarsal retinaculum, you can immediately expose the posterior tibialis tendon, the flexor digitorum and the artery and the nerve as you could see here with a slight fascicular pattern.

Here you can see the cut edge of the flexor retinaculum over the medial malleolus not seen here 'cause it's deeper is going to be the flexor hallucis longus in the tarsal tunnel.

Ultrasound, the normal posterior tibial nerve is usually hyperechoic and of course with a fascicular pattern in the long axis view.

As you could see at the bottom gray scale imaging and on short axis view is going to have a follicular pattern or a relatively hypoechoic structure in comparison to the hyperechoic anisotropic tendons.

Measurements of course vary and you could check that in the literature, but left right comparison would be best.

Ultrasound has great accuracy in looking for masses that would cause compression and changing contour of the posterior tibial nerve and you could see the accompanying arteries by looking at the vascular effects.

Last but not least, another space occupying lesion and we'll show some examples of this would be some neuromas within the tarsal tunnel.

Tarsal Tunnel Syndrome

An example of tarsal tunnel syndrome is exemplified by this individual here as we are more or less at the level of the medial malleolus.

You'll notice, from the bone acoustic landmark of the medial malleolus you have partially anisotropic, the fibrillary pattern of flexor hallucis longus and then you have the vesicular pattern of a nerve.

And finally you have the tubular hypoechoic structure of a vessel, presumably the posterior tibial artery.

Now from the malleolar level we're going to move over to the talar level and now you'll appreciate the change not only in caliber but also echogenicity of the posterior tibial nerve.

Again, the relative preserved fibrillar pattern of the flexor hallucis longus at the posterior joint space or at least medial joint space of the tibiotalar area and a great difference between the mid segment and the distal segment of the posterior tibial nerve.

Here you see the hypoechoic swelling of this nerve compatible with inherent tibial nerve neuropathy and with that of course it causes some compression of the artery.

Once we see that, then you can measure the change in the waistline defect and you could appreciate the fact that there's at least a one third increase of the size of this nerve and loss of the usual vesicular pattern.

But again, left right comparison is very helpful here in the short axis view.

First on the affected left ankle, you would appreciate that not only is the follicular pattern of the nerve enlarged itself but also that it's nerve sheath is apparently edematous and almost imperceptibly.

The unaffected right side with the follicular pattern shows you clearly that there was at least a three times increase in size for the affected side and that the follicular pattern is maintained with the posterior tibial nerve on the unaffected side.

Masses in the Tarsal Tunnel

Once in a while you'll get a big mass, in this case a schwannoma.

Here you see the enlarged portion of the schwannoma with the ingressing vesicular nerve being preserved, the mass proper within the tarsal tunnel and then the egressing portion underneath it.

You could see the sustentaculum tali and behind it, you begin to see the flexor hallucis longus with a bit of anisotropy on short axis view.

Again the same mass occupying the tarsal tunnel.

Compressing the flexor hallucis against the medial wall of the calcaneus.

In 3D brick rendition of this tumor, namely a schwannoma within tarsal tunnel.

We can identify the bone acoustic landmarks of the medial malleolus the talus, and then the calcaneus.

Here you could see the fibrillar pattern of the flexor hallucis longus as it goes towards the posterior part of the ankle.

And above that you'll get to see the vesicular pattern of the nerve track going into the affected side of the schwannoma.

This markedly heterogeneous mass within the tarsal tunnel and kind of recovers again as a fascicular track as it egresses out of the tarsal tunnel.

Above it, you'll see the tubular structure compressed out in the tarsal tunnel and again recovers as it leaves the tarsal tunnel which represents the posterior tibial vessels.

Once in a while you get a completely hypoechoic mass within the tarsal tunnel.

Again, the sound waves accentuate the fibrillary pattern of the flexor hallucis longus as it's no longer impeded by the ganglion cyst.

Above it displayed, as you could see, is the entrapped portion of the pattern of the posterior tibial nerve.

The accompanying MRI of this individual will show you a fluid hyperintense mass lesion and very difficult to appreciate but possibly maybe a vesicular pattern of the nerve just adjacent to it.

And of course the ganglion cyst, as we already noted, was going to be atop the signal void of the flexor hallucis longus.

The same ganglion that we saw in the tarsal tunnel in the long axis view is again also exemplified in the short axis view.

But let's begin with the MRI here you could see on coronal T two that there's indeed increased hyperintensity and the signal aberration represents the ganglion cyst.

Probably not appearing as fluid as we did on the long axis view, but alongside it you may get a hint that indeed this punctate hyperintense structure may represent the nerve on ultrasound.

It's probably easier to identify first, not only the dumbbell shaped ganglion cyst and the slightly anisotropic tendons of the posterior tibial tendon flexor digitorum flexor hallucis longus against the backdrop of the sustentaculum tali, but also that the follicular pattern of the nerve has been markedly displaced and compressed against the tarsal retinaculum.

It is not until you employ dynamic imaging that you begin to appreciate why these individuals have an impingement type of syndrome.

Here in gray scale you can appreciate the translating fibrillary pattern of the flexor hallucis longus against the tibiotalar joint.

And above that you have this ganglion cyst that also partially splays and translates with the flexor hallucis longus.

But when it does that, you could see the buckling of the vesicular pattern of the posterior tibial nerve compressing the posterior tibial vessels and for confirmation that indeed those are vessels.

Here you could appreciate the color Doppler angiography with some aliasing because of the dynamic motion that we've employed in order to look at this individual.

So you've already appreciated on long axis again, you see the vesicular pattern of the nerve being compressed against the translating flexor hallucis longus and of course the flexor retinaculum and the vessels too on short axis view as the flexor hallucis longus translates underneath the sustentaculum tali you'll notice the increasing cyst and of course here you appreciate the vessels.

And one more time, the follicular pattern of the nerve as it is entrapped between the cyst and the tarsal retinaculum.

Posterior Tibial Tendon

The tendons on the medial aspect of the ankle is usually affected and of course the most exposed one is going to be the posterior tibial tendon, a left right comparison showing that the right posterior tibial tendon is at least twice the size of the unaffected side.

And also that there is fluid surrounding partially forming halo around the affected right posterior tibial tendon.

On the long axis view, you'll note that the fibrillar pattern of the posterior tibial tendon is exaggerated because of the fluid around it, representing distention of the tendon sheath of the posterior tibial tendon and the unaffected side shows you a nice parallelity of the fibrillar pattern of the posterior tibial tendon and an imperceptible tendon sheath power Doppler angiography always confirms indeed that this is the affected side.

So in the short axis view, the tendon has become hypoechoic and you see vessels traversing around it and through it, along with a halo surrounding tendon sheath full with fluid on radiographs, you readily appreciate the marked distention of the soft tissue and usually dictated as eccentric soft tissue swelling.

Posterior tibial tendinosis again, if uncared for of course graduates into posterior tibial tendon tears, the more common ones are the ones that start intrasubstance and debride the fibers well within it.

And when that happens, therefore they're usually very tight and taut type of posterior tibial tendon now relaxes and now you'll see a hypoechoic defect slackening of that segment at the level of the talus and almost get to appreciate what should be the distal stump from the proximal stump.

The intraoperative portion shows again the proximal stump and the distal stump of the tendon and of course the dehisced segment that occurred well within this posterior tibial tendon When that happens.

Now posterior tibial discontinuity increases over time.

Here in this drawings you could see fluid filled space between the proximal and distal stumps.

Over time a fibrous scar forms between these two stumps and of course the tendon sheath and some more cables and possibly even some threads are left and that's what you get to appreciate on gray scale imaging using ultrasound.

First, let's look at the unaffected site wherein you see within the malleolar groove of the medial malleolus that there is the preserved fibrillar pattern of the unaffected side.

While on the opposite side you cannot find a tendon and once you employ the short axis view, you'll see that you have an empty malleolar groove on the medial malleolus in comparison to the unaffected side that shows a clear cut bristle pattern of the tendon at the level of the medial malleolus, there's a spectrum of posterior tibial tendon tears.

You already have seen something that dehisces like wet kleenex or tissue paper to ones that transect across the tendons and usually when transected they may occur just at the level of the medial malleolus or approaching the talo navicular region.

It is the longitudinal tear that's intrasubstance.

That is a little bit more challenging and we'll get to see that later.

We get to see it as a signal void.

On this MRI behind the medial malleolus here you could see a distortion of the contour of the posterior tibial tendon at the level of the malleolus and the rest of the posterior tibial tendon is signal void clearly being normal into the navicular region.

The intermediate signal aberration is very difficult to figure out.

Its partial volume averaging synovitis, but it wouldn't be simpler to employ ultrasound and confirm indeed that the usual hyperechoic bristle pattern of a short axis view of the posterior tibial tendon within the malleolar groove is affected.

Seen here is a hypoechoic cleft giving this usually homogenous hyperechoic structure, a coffee bean contour and surrounding fluid in distention of its tendon sheath confirmatory of incompetent tenosynovitis.

With this tendon tear on short axis view, you not only saw what's happening to the tendon's tendon sheath, but it also appreciate the fact that there are changes affecting the flexor retinaculum and some early cortical changes of the bony medial malleolus.

In the long axis view, again what you expect it to be.

Uniform fibrillar pattern has an intrasubstance hypoechoic defects separating the superficial from the deep side.

Again, long axis short axis, your confirmation of an intrasubstance longitudinal split of the posterior tibial tendon.

This individual's intraoperatively will show indeed that it is an intrasubstance tear clearly seen here as they put a probe into the intrasubstance portion of this individual, mostly in obese or postpartum individuals that have this problems, we've seen the posterior ankle and now let's look at the lateral ankle and we get to meet the pair of peroneus longus and peroneus brevis tendons.

The Lateral Ankle

We will reserve the tibiotalar fibular ligament.

When we address the ligaments towards the end of this lecture schematically normally you'll remember that the peroneus brevis is closer to bone brevis B brevis for bone B For B the longus is L lateral or for longus away from bone.

They usually sit behind the malleolar groove of the lateral malleolus right behind the fibula.

Those that are affected may usually slide laterally and anteriorly and once that happens the fibula begins to chafe against the peroneus brevis.

Unfortunately, for the peroneus brevis the longus contributes because it entraps the brevis against the bony fibula.

Over time, the bony fibula creates a spur which now becomes more like a blade, and as this blade cuts and chafes through the peroneus brevis, it'll eventually affect the peroneus longus illustrated.

Here you could see that the peroneus brevis has been chafed by the bony fibula and trapped between the fibula and the relatively preserved peroneus longus on short axis view.

What we will see is that the sometimes normal variant C shape brevis has now a cleft.

So on this short axis view within the malleolar groove of the fibula, you'll notice that there are three tendons when we only expect to first the relatively preserved peroneus longus, but surrounded with some tenosynovitis and the split of the peroneus brevis.

But like we showed you an earlier illustration that over time if uncared for even the peroneus longus will be affected.

Thus here you could see that the hypertrophy of the spur of the fibula now punctures not only the brevis but also the longus.

When that happens, now we begin to see a complete disorganization.

We just have too many tendons when we expected to.

So here you could see that the C shape peroneus brevis has a split and but the usually oval or round hyperechoic bristle pattern of the peroneus longus equally shows that it is losing and fragmenting its sides.

On the long axis view, you expect to see at least only two tendons.

Instead, we have multiple tendons representing the different fragments and longitudinal split defects of the peroneus tendons.

The stress views we employ in these individuals is dorsiflexion and eversion as you could see here.

Sometimes we're going to ask the patient to do it actively, but if they cannot or they cannot follow our instructions, we bolster the calcaneus park, the transducer underneath the fibula and behind it.

We'd look for the two peroneal pairs.

Here you could see a dorsiflexion and eversion maneuver as shown clearly.

If the patient can do it passively, it'll be great because what happens in the subluxing tendons, as you could see here, they click anteriorly and both pairs do that.

Sometimes the longus goes over the brevis or the brevis may leave the longus behind, but clearly you can appreciate that the from the posterior location they go anteriorly.

The accompanying video clip of another patient is not.

The same patient shows you that spontaneously this individual can sublux her tendon all by herself on active movement.

So this is what we get to see and feel.

Now of course when you get to see to in this individual, it's very, very dynamic and very, very exquisite.

But an ultrasound we can at least detect the different parts of the tendons or which pair of the tendons of LXi.

And also you may begin to appreciate what's happening to the tendon.

As the fibula chafes or cuts into either the brevis and or the longus for the anterior ankle, we're going to take a quick look at the different structures and of course, very importantly, let's begin by taking a look at the ligaments.

Ankle Ligaments

The all important ligament is going to be the anterior talofibular ligament.

And again, because it is a ligament, we're going to connect bone to bone bony fibula to the bony neck of the talus.

And you're here you see the packed fibrillar pattern of the anterior talofibular ligament preserved and intact when it is acutely sprained.

As you could see on the Netter drawing.

Now we begin to appreciate a hypoechoic cleft transecting the loss of the fibrillary pattern or packed fibrillar pattern of the anterior talofibular ligament, and of course collecting a subcutaneous edema in the underneath the skin of this patient.

So this ankle sprains do have to be addressed within 72 hours.

Otherwise they may heal and bridge but not normally.

You could still see some fluid collection and sometimes some disparity in the echo signature.

The usual fibrillar pattern of these ligaments here again, left right comparison is very helpful.

As you could see on the unaffected left side, you could see the packed fibrillar pattern of the ligament as it bridges from the fibula to the neck of the talus and an acutely swollen one.

Again, loss of the fibrillar pattern.

But also note that you might have an avulsion fragment as you could appreciate.

Here you got this high level echoes along the subfibular portion or the subfibular portion of the fibula, which may represent some avulsion fragments.

Once in a while you may begin to appreciate the fact that the ankle ligaments form a circle.

So if you do affect the lateral side, you may also affect the medial side.

Here on an AP view you could see concentric soft tissue swelling off the ankle lateral greater than medial.

But when you get the lateral view, all of a sudden you'll see this widened medial clear space representing some disruption of the medial or the deltoid ligament.

So this will behoove you to quickly examine both the lateral and medial aspects of the ankle.

If you are concerned about bimalleolar soft tissue swelling, individuals with deltoid ligament tears will show a widened medial clear space.

As you can appreciate on the frontal radiographs, not necessarily a mortise or oblique view.

Left right comparison is always helpful.

Here in a cadaver study where we created tears of the deltoid ligament, you could see that the anterior bundle formed by the more superficial talonavicular and a deeper talotibial.

You could appreciate the fact that the packed fibrillar patterns are again intact.

Here on the gray scale imaging and ultrasound on the unaffected side, you'll see the superficial tibiotalar navicular bundle or superficial level, and then you have the tibiotalar fibrillar pattern representing the deep pattern.

So this is intact, and when artificially created you could see the disruption, the hypoechogenicity, and of course the retracted ends of both superficial and deep fibers of this anterior bundle of the deltoid ligament.

It's become very important to us to look at the medial portion of the ankle because we have appreciated high ankle sprains.

When the deltoid ligaments are affected, we now also concentrate not only on the more inferior tibiotalar fibular, but also the higher level fibulotibial ligament, also known as the syndesmosis here case in point, for example, we can clearly see that after addressing the lateral portion and the medial portion of the ankle.

When we look at the fibulotibial ligament, the unaffected side shows a packed fibrillar pattern with a little bit of anisotropy on the tibial side.

The affected side of the syndesmosis shows you a markedly swollen and distorted fibulotibial ligament with high level echoes representing avulsion fragments.

This has become important to us because from the classical talofibular ankle sprains, we have now come up with high ankle sprains.

So in the professional national football league players, we noticed that usually they planted foot has an acute eversion and causes a tear of the syndesmosis and this gives them a lack of a takeoff sooner or later.

There's a big difference between treating the classical ankle sprain, where in most of these individuals might even have just some bandaging or some short week type of casting.

In high ankle sprains, we're looking at longer castings and sometimes as syndesmotic screw for these individuals long enough is eight weeks, which is already half their football season.

Summary

So in summary, therefore we have gone through the fact that ultrasound is the most exquisite modality.

Look at tendons. We've shown you great cases about the Achilles tendon, the posterior tibial, and of course the pair of peroneal tendons.

Also, we've seen that instability of the ankle is usually secondary to ligaments and that we've seen and appreciated the fact that ultrasound can address the ligaments in the heel cord structure of the Achilles tendon and the plantar fascia.

We've seen nice cases of inflammation of the aponeurosis, of the plantar fascia.

Last but not least, you have begun to appreciate the fact that ultrasound is being used more for peripheral nerves and what we started as carpal tunnel.

We're now looking at other types of nerves including the tarsal tunnel.

And so with that I'd like to thank you so much.