II. Causes

  1. Overhead throwing athlete (including teen athletes), especially in the cocking phase of overhead throwing

III. Pathophysiology

  1. Internal Shoulder Impingement (where supraspinatus tendon inserts on Humerus)
    1. Occurs with Humerus at end-point of external rotation (with Shoulder abducted)
    2. Constrast with typical Shoulder Impingement where the supraspinatus tendon is impinged beneath the AC joint
  2. Supraspinatus tendon becomes entrapped
    1. May cause partial tear or avulsion at the supraspinatus insertion on lateral Humerus (articular aspect of supraspinatus)

IV. Grading: Articular-sided Supraspinatus Tendon Avulsion

  1. Grade 1 partial supraspinatus tear
    1. Supraspinatus tendon avulsion <3mm
  2. Grade 2 partial supraspinatus tear
    1. Supraspinatus tendon avulsion 3-6 mm
  3. Grade 3 partial supraspinatus tear
    1. Supraspinatus tendon avulsion >6 mm (or >50% avulsion)

V. Symptoms

  1. Empty Cans Test
    1. Test Sensitivity: 70% (contrast with 98% for a complete tear)
    2. Test Specificity: 58%

VI. Imaging

  1. MR Arthrogram of the Shoulder
    1. Preferred over standard MRI Shoulder for identifying PASTA Injury
    2. Test Sensitivity: 62% (contrast with 95% for a complete tear)
    3. Test Specificity: 92%

VII. Management: Shoulder rehabilitation (Non-surgical management)

  1. Anticipate 6-12 weeks of rehabilitation
  2. Shoulder strengthening
    1. Rotator cuff Muscle Strengthening
    2. Core Muscle Strengthening
  3. Shoulder Stretching
    1. Cross arm stretch
      1. Arm reaches across chest across the opposite Shoulder
      2. Opposite arm is flexed at the elbow holding the crossed arm in place
  4. Sport-specific modification
    1. Correct predisposing overuse

VIII. Management: Arthroscopic Shoulder surgery

  1. Refractory Grade 1 and 2 tears (<50% tear) or labral fraying
    1. Debridement
  2. Grade 3 tears
    1. Surgical Repair

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