HSS Ultrasound of the Month Case #91

Clinical History A 75 year old male presents with bilateral, left greater than right, ankle pain and swelling for 1 week following the completion of a 10 day course of Levaquin for a diarrheal illness acquired in India.

On exam, the patient demonstrated bilateral, left greater than right, ankle swelling with slight tenderness over the Achilles tendon; however, the patient was able to plantar and dorsiflex both feet.

Clinical concern was for bilateral peroneal and Achilles tendinopathy.

Diagnostic ultrasound evaluation of the left ankle and Achilles tendon was requested.

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Diagnosis: Complete tear of the left Achilles tendon.

High grade partial tear of the right Achilles tendon.

Management Surgery was not pursued in this case given the patient’s age and activity level.

Instead, the patient opted for a more conservative treatment plan, which consisted of a removable boot with a wedge for his left ankle, as well as a brace for his right ankle in an effort to minimize the chance of subsequent right Achilles tendon rupture.

It was explained to the patient that he would likely have some weakness on the left side, but should be able to build up acceptable strength over time.

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Discussion • Epidemiology: —

Middle-aged men

• Predisposing factors: — — — — — —

Occasional athletes (“weekend warriors”) Repeated microtrauma Diabetes Mellitus Inflammatory conditions (rheumatoid arthritis, systemic lupus erythematosus) Intratendinous steroid injection Fluoroquinolone antibiotics (4 fold increased risk)

• Mechanism of injury: — —

Sports related trauma Rapid plantar flexion or forceful dorsiflexion of a plantar flexed foot

• Clinical presentation: — —

Audible pop with associated posterior ankle pain and swelling Weakened plantar flexion with more pronounced passive dorsiflexion

• Pathology: —

Ruptures commonly occur in the critical zone, a relatively hypovascular region approximately 4-6 cm proximal to the calcaneal insertion

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Discussion • Imaging: — —

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Radiographs: • Obliteration of Kager’s fat pad Ultrasound: • Partial thickness tear: Abnormally hypoechoic or anechoic regions superimposed on an abnormally thickened and hypoechoic tendon • Full thickness tear: Background of hypoechoic tendinosis with a superimposed contour change and separation of the torn tendon edges, which demonstrate posterior acoustic shadowing MRI: • Partial thickness tear: Altered tendon architecture with disruption of some of the tendon fibers and associated T2 signal hyperintensity • Full thickness tear: Discontinuous tendon with retraction of the torn tendon fibers and edema and hematoma filling the gap

• Treatment: — —

Partial thickness tear: Conservative management Full thickness tear: Surgical repair • Superior functional result • Diminished rate of re-rupture

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