How is a left shoulder rotator cuff assessed?

Assessment of Left Shoulder Rotator Cuff

MRI, MR arthrography, and ultrasound are all highly appropriate imaging modalities for evaluating rotator cuff pathology, with the choice depending on local expertise and specific clinical suspicion.

Clinical Examination Components

Range of Motion Testing

• Assess active and passive range of motion using a goniometer for:
  • Forward flexion
  • Abduction
  • External rotation
  • Internal rotation 1
• Compare with the contralateral shoulder to identify asymmetry 1

Strength Testing

• Evaluate strength using a dynamometer when available for:
  • Supraspinatus: Empty can test (arm at 90° forward flexion, 30° horizontal adduction, thumb down) 1, 2
  • Infraspinatus: External rotation with arm at side 2
  • Subscapularis: Lift-off test or belly-press test 1, 2
  • Teres minor: External rotation with arm abducted 90° 2

Special Tests

• Impingement signs:
  • Neer test: Passive forward elevation of internally rotated arm 2
  • Hawkins-Kennedy test: Forward flexion to 90° followed by forceful internal rotation 2
• Rotator cuff integrity:
  • Drop arm test: Patient unable to maintain 90° abduction (indicates supraspinatus tear) 2
  • External rotation lag sign: Inability to maintain external rotation (indicates infraspinatus tear) 1
  • Internal rotation lag sign: Inability to maintain internal rotation (indicates subscapularis tear) 1
• Biceps tendon involvement:
  • Speed's test: Resisted forward flexion with supinated forearm 1
  • Yergason's test: Resisted supination with elbow flexed 90° 1

Imaging Assessment

Initial Imaging

• Plain radiographs should include:
  • AP view
  • Grashey view (AP to scapula, with patient rotated 30° posteriorly)
  • Axillary lateral view or scapular Y view 3
• Special views for specific concerns:
  • Suprascapular outlet view or Rockwood view (30° angled caudad) for evaluating anterior acromion and impingement 3

Advanced Imaging Options

MRI

• Usually appropriate for evaluating rotator cuff pathology 3
• Provides high sensitivity and specificity for full-thickness tears 3
• Can assess muscle atrophy and fatty infiltration, which influence treatment decisions and prognosis 3
• Can identify partial-thickness tears, though with lower sensitivity than MR arthrography 3

MR Arthrography

• Particularly valuable for:
  • Patients under 35 years with suspected labral tears 3
  • Distinguishing between partial and full-thickness tears 3
  • Evaluating the undersurface of the rotator cuff 3
• Superior to conventional MRI for detecting partial-thickness articular surface tears 3

Ultrasound

• Equivalent to MRI for detecting full-thickness rotator cuff tears 3
• Operator-dependent with variable sensitivity for partial-thickness tears 3
• Can evaluate the acromioclavicular joint, rotator cuff tendons, and long head of biceps tendon 3
• Allows for dynamic assessment and guided interventions 3

Post-Surgical Evaluation

• For suspected rotator cuff retear after repair:
  • MRI, MR arthrography, and ultrasound are all appropriate options depending on local expertise 3
  • If MRI or ultrasound unavailable, CT arthrography or X-ray arthrography may be considered 3

Treatment Considerations

• Conservative management includes:

  • NSAIDs for pain control 4
  • Physical therapy focusing on rotator cuff strengthening 4, 5
  • Subacromial corticosteroid injections 4

• Surgical intervention typically reserved for:

  • Patients failing conservative treatment 4
  • Young and middle-aged adults with full-thickness tears 4
  • Cases with significant functional impairment 5

• Post-surgical rehabilitation involves:

  • Initial period of immobilization 5
  • Gradual progression from passive to active exercises 5

Clinical Pitfalls and Caveats

• Asymptomatic rotator cuff tears occur in approximately 10% of cases, so imaging findings must be correlated with clinical presentation 3
• Shoulder instability can mimic rotator cuff pathology and should be considered in the differential diagnosis 3
• Ultrasound assessment is highly operator-dependent and requires specific expertise 3
• Retear rates after surgical repair approach 20%, particularly with larger initial tears 4
• Advanced rotator cuff arthropathy may require different treatment approaches including reverse total shoulder arthroplasty 6