II. Causes
- Overhead throwing athlete (including teen athletes), especially in the cocking phase of overhead throwing
III. Pathophysiology
- Internal Shoulder Impingement (where supraspinatus tendon inserts on Humerus)
- Occurs with Humerus at end-point of external rotation (with Shoulder abducted)
- Constrast with typical Shoulder Impingement where the supraspinatus tendon is impinged beneath the AC joint
- Supraspinatus tendon becomes entrapped
- May cause partial tear or avulsion at the supraspinatus insertion on lateral Humerus (articular aspect of supraspinatus)
IV. Grading: Articular-sided Supraspinatus Tendon Avulsion
- Grade 1 partial supraspinatus tear
- Supraspinatus tendon avulsion <3mm
- Grade 2 partial supraspinatus tear
- Supraspinatus tendon avulsion 3-6 mm
- Grade 3 partial supraspinatus tear
- Supraspinatus tendon avulsion >6 mm (or >50% avulsion)
V. Symptoms
-
Empty Cans Test
- Test Sensitivity: 70% (contrast with 98% for a complete tear)
- Test Specificity: 58%
VI. Imaging
- MR Arthrogram of the Shoulder
- Preferred over standard MRI Shoulder for identifying PASTA Injury
- Test Sensitivity: 62% (contrast with 95% for a complete tear)
- Test Specificity: 92%
VII. Management: Shoulder rehabilitation (Non-surgical management)
- Anticipate 6-12 weeks of rehabilitation
-
Shoulder strengthening
- Rotator cuff Muscle Strengthening
- Core Muscle Strengthening
- Shoulder Stretching
- Cross arm stretch
- Arm reaches across chest across the opposite Shoulder
- Opposite arm is flexed at the elbow holding the crossed arm in place
- Cross arm stretch
- Sport-specific modification
- Correct predisposing overuse
VIII. Management: Arthroscopic Shoulder surgery
- Refractory Grade 1 and 2 tears (<50% tear) or labral fraying
- Grade 3 tears
- Surgical Repair