Rim rent tear of rotator cuff

A rim rent tear of the rotator cuff, also known as partial articular surface tendon avulsion (PASTA), is a specific subtype of partial-thickness rotator cuff tear that involves the articular surface footprint at the site of tendon attachment into the greater tubercle ². Such small tears can extend along the tendon fibres, causing tendon delamination, which corresponds to Snyder’s III or IV classification.

This sort of tear is relatively common and also can involve the infraspinatus tendon ³.

Involvement of the bursal surface can also occur (reverse PASTA).

Epidemiology

PASTA lesions are frequent in overhead athletes, younger people and smoker patients.

Pathology

• Intrinsic factors: ageing with changes of rotator cuff vascularity and metabolic changes associated

• Extrinsic factors:

1. shear stresses on the supraspinatus tendon fromnarrowing of the coracoacromial arch (extrinsic impingement)

2. microtrauma from repetitive contact of the articular surface of the supraspinatus and infraspinatus tendons with the posterosuperior part of the glenoid during arm abduction and lateral rotation.

Clinical presentation

Not all PASTA lesions are symptomatic. Often shoulder pain when lifting outwards, overhead and throwing.

Radiographic features

Plain radiograph

X-ray of the shoulder with anteroposterior view, axillary lateral view and a supraspinatus outlet view, but are not specific.

Ultrasound

May be seen as an echogenic edge and a cortical defect at the footprint. Howewer anisotropy artifacts often make it difficult to recognise partial articular supraspinatus tendon avulsion (PASTA) by ultrasound

MRI

PASTA lesion appear in coronal T2images and in Glenohumeral (shoulder) arthrography as linear fluid signal defects at the articular surface of the supraspinatus tendon, near the attachment (footprint) on bone interface.

Treatment and prognosis

Initially conservative treatment with activity modification, without overhead or pain-provoking actions, and physical therapy.

Surgery if the pain is not coming down by three to six months of nonoperative treatment and than one half of the thickness of the supraspinatus tendon is torn.

Surgical options

• arthroscopic debridement of the tear

• debridement with acromioplasty

• rotator cuff repair with or without acromioplasty

History and etymology

The term “rim-rent” was first used by the American surgeon Ernest Armory Codman in 1934 ^3-4.