HSS Ultrasound of the Month #106

Clinical History A 47 year old female presents with left ankle pain and swelling 10 days after rolling her ankle while hiking in the woods, when she felt a splinter pierce the top of her foot.

She was seen in a local urgent care clinic, where she was diagnosed with an ankle sprain and ankle cellulitis. She was given a tetanus shot and started on Keflex 6 days ago; however, reports that her cellulitis has not significantly improved.

On exam, there was ankle and foot swelling with a 5 x 4 cm area of cellulitis along the lateral ankle and a healed punctate puncture wound just distal to the lateral malleolus, without associated fluctuance or drainage.

Clinical concern was for foreign body.

Ultrasound evaluation of the left ankle was requested.

Ultrasound of the Month – Case 106

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Ultrasound of the Month – Case 106

Diagnosis: Foreign body within the peroneal tendon sheath with associated tenosynovitis and peroneus brevis tendon tear.

Treatment Removal of a 1.5 cm splinter from the peroneal tendon sheath Peroneus brevis debridement and repair

Ultrasound of the Month – Case 106

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Discussion Retained soft tissue foreign bodies typically result from penetrating injury.

Foreign bodies are most commonly wood, glass, or metal structures.

Retained foreign objects result in a surrounding inflammatory reaction and with time may form encasing granulation tissue.

It is crucial to identify a foreign body before it results in infection or causes damage to the surrounding structures.

Ultrasound of the Month – Case 106

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Discussion •

Imaging Findings: – Radiography: • Initial work up • However, many foreign bodies, such as wood and plastic, will not be seen on plain films as they are not radio-opaque.

– Ultrasonography: • Echogenic object with posterior acoustic shadowing • A hypoechoic rind of inflammatory tissue with associated vascularity may also be seen

Ultrasound of the Month – Case 106

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