Paratenonitis describes the inflammation of the paratenon, a membrane-like structure in tendons without synovial sheath 1,2.
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Terminology
Paratenonitis has sometimes also been referred to as "peritendinitis" 2 or "paratendonitis" 3.
Epidemiology
Paratenonitis is common but the frequency depends on the tendon involved. It is commonly found in athletes as a result of overuse injury 1.
Risk factors
dancers
long-distance runners
Diagnosis
The diagnosis can be established by a combination of typical clinical and typical imaging findings.
Clinical presentation
Local pain and swelling, tenderness on palpation along the anatomic course of the tendon 4 and movement restriction in the chronic stage 1.
Pathology
Etiology
Paratenonitis can develop as a result of overuse or repetitive microtrauma 1.
Location
Paratenonitis affects tendons with a paratenon and thus without a synovial sheath e.g. Achilles tendon, patella tendon, gluteal tendons, etc 1. The most common location of paratenonitis is the Achilles tendon.
Radiographic features
Ultrasound
On ultrasound, paratenonitis might appear as a linear hypoechoic lining around the tendon with associated hyperemia on color Doppler in chronic inflammation 2.
MRI
In the acute phase, a linear fluid intensity 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 1,2.
T1: hypointense
T2/PD: hyperintense
STIR/PDFS: hyperintense
T1 C+ (Gd): enhancement
Radiology report
A description of the following features should be in the radiology report:
inflammatory changes of the paratenon
presence or absence of tendinopathy
presence or absence of tendon tears or rupture
Treatment and prognosis
Treatment is usually conservative with nonsteroidal anti-inflammatory drugs, activity modification, physical therapy 4. If conservative management fails, paratenon stripping can be performed.
Complications
Chronic paratenonitis can further progress into tendinopathy and tendon tears.