Paratenonitis

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Paratenonitis describes the inflammation of the paratenon, a membrane-like structure in tendons without synovial sheath .

Terminology

Paratenonitis has sometimes also been referred to as ‘peritendinitis’ or ‘paratendonitis’ .

Epidemiology

Depends on the tendon involved, commonly found in athletes as a result of overuse injury .

Risk factors

dancers
long-distance runners

Clinical presentation

Local pain and swelling, tenderness on palpation along the anatomic course of the tendon and in chronic stages movement restriction .

Complications

Chronic paratenonitis can further progress into tendinopathy and tendon tears .

Pathology

The paratenon is a vascularized, membrane-like structure in tendons without a synovial sheath, which acts as a gliding mechanism towards the adjacent tissues and supplies the tendon with blood . Paratenonitis develops as a result of overuse and repetitive microtrauma.

Location

Affects tendons without synovial sheath e.g. Achilles tendon, patella tendon gluteal tendons, etc. . The most common location of paratenonitis is the Achilles tendon.

Radiographic features

Ultrasound

Linear hypoechoic structure around the tendon with associated hyperemia on color Doppler in chronic inflammation .

MRI

In the acute phase, a linear fluid-intense structure can be seen around the tendon. In the chronic phase soft-tissue, scar-like structures can be seen extending into the peritendinous fatty tissue .

Signal characteristics

T1: hypointense
T2/PD: hyperintense
STIR/PDFS: hyperintense
T1 C+ (Gd): enhancement

Treatment and prognosis

Treatment is usually conservative with nonsteroidal anti-inflammatory drugs, activity modification, physical therapy . If conservative management fails, 'paratenon stripping' can be performed.