Rotator cuff tear

Last revised by Han Xin Lau on 22 Sep 2024

Rotator cuff tears are one of the most common causes of shoulder pain mostly in older patients.

The prevalence of tears increases with age. The most significant findings are impingement and "arc of pain" sign (pain while lowering the abducted arm) 1. Supraspinatus weakness, night pain and weakness of external rotation (seen in infraspinatus tear) may also be present.

Important causes include:

  • traumatic

    • acute

    • chronic repetitive

  • degenerative

Rotator cuff tears can affect each one of the rotator cuff tendons and often more than one 3-5:

Rotator cuff tears can occur at different locations of the tendon, and more than one location can be involved 3-5:

  • tendon insertion (footplate): often degenerative

  • critical zone: degenerative or trauma-related

  • myotendinous junction: often trauma-related, infraspinatus muscle most often affected

A modification of the original Codman classification (1930) may be used to categorize tears:

Exact features depend on the type of tear. General features include

Typically, these are normal in acute tears with chronic tears showing degenerative-type changes 1:

  • may show a decreased acromiohumeral interval

  • may show decreased supraspinatus opacity and decreased bulk due to fatty atrophy in chronic tears

  • humeral subluxation superiorly may be seen in chronic tears

  • may show features of subacromial impingement

    • spur formation on the undersurface of acromioclavicular joint

    • acromion with an inferolateral tilt seen on outlet view (i.e. modified 'Y' view)

    • type III acromion

  • secondary degenerative changes: sclerosis, subchondral cysts, osteolysis, and notching/pitting of greater tuberosity

Ultrasound may have up to 90% sensitivity and specificity. It can also reveal other mimics like tendinosis, calcific tendinitis, subacromial-subdeltoid bursitis, greater tuberosity fracture, and adhesive capsulitis.

Full-thickness tears extend from the bursal to the articular surface, while partial-thickness tears are focal defects in the tendon that involve either the bursal or articular surface. Full-thickness appear on ultrasound as hypoechoic/anechoic defects in the tendon. Due to the fluid replacing the tendon, cartilage shadow gets accentuated giving a double cortex or cartilage interface sign. Also, due to the defect, overlying peribursal fat dips down into the tendon gap, creating a sagging peribursal fat sign 1.

Direct signs are:

  • non-visualization of the tendon

  • hypoechoic discontinuity in the tendon

Indirect signs are:

Secondary associated signs are:

  • cortical irregularity of greater tuberosity

  • shoulder joint effusion

  • fluid along the biceps tendon

  • fluid in the axillary pouch and posterior recess

Full-thickness tears are easier to diagnose on MRI than partial-thickness tears 2. Hyperintense signal area within the tendon on T2W, fat-suppressed, intermediate-weighted and GRE sequences, usually matches to fluid signal. They extend from the articular to the bursal surface. The presence of a tendon defect filled with fluid is the most direct sign of rotator cuff tear. Tendon retraction may also be present, which can be graded using the Patte classification. Indirect signs on MRI are - subdeltoid bursal effusion, medial dislocation of biceps, fluid along biceps tendon, and diffuse loss of peribursal fat planes. Muscle atrophy and fatty replacement is seen in chronic cases and can be graded using the Goutallier classification, or assessed with the tangent sign or scapular ratio 9,10.

Partial-thickness tears extend to either the bursal or articular surface, and sometimes they are interstitial which means confined within the tendon. Retraction of tendinous fibers from the distal insertion into the greater tuberosity may also be considered partial tear.

Chronic tears show signs of extensive use or repetitive stress, which can be reflected by intramuscular cystic changes and tendinosis in the remaining tendon. There are often risk factors for subacromial impingement present for example degenerative changes at the acromioclavicular joint or acromioclavicular joint cysts.

MR arthrography may enhance the detection of rotator cuff tears, especially full-thickness tears.

General imaging differential considerations include:

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