Ultrasound for Achilles Tendon Rupture

Ultrasound for Achilles Tendon Rupture

By Stephen Alerhand MD (@SAlerhand)
EM Resident Physician, Icahn School of Medicine at Mount Sinai

Edited by Alex Koyfman MD (@EMHighAK)

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Case Scenario…

A 35 year-old construction worker presents to the emergency department with right lower leg pain. It began all of a sudden while he was using all his weight to push a large cart containing large metal planks. Since then, he has barely been able to ambulate, not necessarily due to significant pain on weight-bearing but rather due to a heavy dragging sensation of his lower leg. The pain is poorly localized to the entire lower leg and feels dull. He denies any numbness or tingling. Motrin has provided only mild relief of pain.

Physical Exam

LOOK. RANGE. FEEL.

– On close examination of the right leg, there is very mild swelling near the tendo-calcaneal junction. Otherwise, there is no bruising, ecchymoses, or open wounds / lacerations.

– He demonstrates full active flexion and extension around the knee joint. He can move all toes. However, while dorsiflexion of the ankle is intact, his plantarflexion is weak and nearly absent.

– He has intact sensation to light touch throughout the extremity, with 2+ dorsalis pedis pulses palpated. There is tenderness to palpation near the tendo-calcaneal junction.

– You stand him up on his right leg with his left knee resting on the stretcher, with the knee bent at 90 degrees. You squeeze the left mid-calf and the ankle plantarflexes. Great, this is normal. Now, you try the same maneuver on the opposite affected leg, but the ankle barely plantarflexes. This is a positive Thompson’s test, and you suspect an Achilles tendon rupture (likely partial).

Back to Case Scenario

As you work at a large academic center, you get set to call Orthopedics about your suspected Achilles tendon rupture. Before you do so, you order the tibia/fibula x-ray, because let’s face it – Orthopedics will not come the patient unless they have an x-ray with bones to look at.

At this point, your Ultrasound fellow suggests an alternative… possibly the only way to ever get an Orthopedics consult without having an x-ray to show them.

The Literature is Conflicting

Kayser, R. Mahlfeld, K. Heyde, CE. Partial rupture of the proximal Achilles tendon: a differential diagnostic problem in ultrasound imaging. Br J Sports Med. 2005 Nov; 39(11):838-42; discussion 838-42.
Type of study: prospective
Question: whether US can correctly visualize partial rupture of proximal Achilles
Results: sensitivity 50%, specificity 81%
Conclusions: US is useful tool but not sufficiently reliable. Diagnosis must be established by MRI.

Alfredson, H. Masci, L. Ohberg, L. Partial mid-portion Achilles ruptures: new sonographic findings helpful for diagnosis.
Type of study: prospective
Objective: evaluate US findings in patients with suspected partial Achilles rupture
Findings: US showed disrupted dorsal tendon line and irregular tendon structure
Conclusions: US can be a helpful tool to diagnose mid-tendon Achilles rupture.

Margetic, P. Miklic, D. Rakic-Ersek, V. Doko. Z. Lubina, Zi. Brkljacic, B. Comparison of ultrasonographic and intraoperative findings in Achilles tendon rupture. Coll Antropol. 2007 Mar;31(1):279-284.
Type of study: prospective
Objective: assess value of US in diagnosis of Achilles rupture by comparison to direct intraoperative findings
Results: length of tendon and size of rupture showed measured by US and during surgery showed high correlation
Conclusions: US is an excellent imaging method for confirming clinical diagnosis of Achilles rupture as well as for following up process of tendon healing.

Assessment

In sum, there are several more studies pointing to the *usefulness* of US for diagnosing Achilles tendon rupture. However, exact diagnosis may often require MRI imaging. Of course, physical exam itself is often sufficient on its own. In any case, the combination of physical exam (+ Thompson’s test) and ultrasound may be beneficial in identifying an Achilles tendon rupture for your Orthopedic consult. Ultrasound is cheap, readily available, provides easy contralateral evaluation, and can assess dynamic motion.

How to perform the Ultrasound

-Lay patient prone on the table.
-Put the ankle at slight dorsiflexion, close to 90-degree angle with the tibia.
-Use the linear probe.
-Beginning at the tendo-calcaneal attachment, move proximally in the longitudinal plane.
-The Achilles appears linear and echogenic.
-Proximally, the tendon blends in with the gastrocnemius and deeper soleus, its muscles of origin.
-In the transverse plane, it has a mostly flat or concave anterior margin.
-Plantarflex the ankle and assess for tears. For example, one part may move and the other will not (or will move less).
-Rupture usually occurs 2-6 cm proximal to the calcaneal insertion site

-Full thickness tear: contour change of the tendon; acoustic shadowing at the tear margins with adjacent hypoechoic tendinosis

NORMAL

normal mid-Achilles
Mid-tendon

normal Achilles at calcaneal insertion
At calcaneal insertion site
http://arg.co.nz/media/newsletter/files/2013/10/18/mar_2007.pdf

RUPTURE
achilles longitudinal rupture

Longitudinal

achilles transverse rupture
Transverse
http://www.ultrasoundcases.info/Case-List.aspx?cat=407)

 

References / Further Reading
http://www.ajronline.org/doi/full/10.2214/AJR.09.3111
http://www.ultrasoundcases.info/Case-List.aspx?cat=407
http://arg.co.nz/media/newsletter/files/2013/10/18/mar_2007.pdf
https://www.youtube.com/watch?v=835u0mOvA6o
https://www.youtube.com/watch?v=g74UgrozB9M
http://www.ncbi.nlm.nih.gov/pubmed/22608601
http://www.ncbi.nlm.nih.gov/pubmed/21406322

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