What is the O'Brien test of the shoulder?

The O'Brien Test of the Shoulder

The O'Brien test (also known as the Active Compression Test) is a physical examination maneuver used to evaluate for labral tears of the shoulder, particularly posteroinferior labral tears, though it was originally designed to detect superior labrum anterior to posterior (SLAP) lesions. 1

Technique for Performing the O'Brien Test

1. Patient Position: Have the patient stand with the affected arm flexed to 90 degrees and adducted 10-15 degrees across the body
2. Hand Position: The patient's thumb points downward (internal rotation/pronation)
3. Resistance: Apply downward pressure on the arm while the patient resists
4. Test Repetition: Repeat the test with the palm facing upward (external rotation/supination)
5. Interpretation: The test is positive if pain is produced with the thumb-down position and reduced or eliminated in the palm-up position

Diagnostic Value

• Sensitivity and Specificity:

  • For posteroinferior labral tears: 83% sensitivity, 62% specificity 1
  • For SLAP lesions: 65% sensitivity, 50% specificity 1
  • Overall sensitivity: 63%, specificity: 73% 2

• Recent research shows the O'Brien test demonstrates higher diagnostic value for posteroinferior labral tears than for SLAP tears, despite being originally designed for SLAP lesions 1

Clinical Context and Limitations

• No single physical examination test for labral tears provides definitive diagnosis
• Decision for surgical intervention should not be based on clinical examination alone 2
• Combining tests can improve diagnostic accuracy:
  • The O'Brien test combined with the crank test offers improved sensitivity 3
  • Using tests in series improves specificity; using tests in parallel improves sensitivity 3

Imaging After Positive Test

If the O'Brien test is positive, appropriate imaging should be considered:

• Initial imaging: Plain radiographs (AP view, Grashey view, axillary lateral or scapular Y view) 4, 5
• Advanced imaging options (in order of preference):
  1. MR arthrography (86-100% sensitivity) - gold standard, especially for patients under 35 years 4, 5
  2. Standard MRI without contrast (with optimized imaging equipment) 4, 5
  3. CT arthrography (if MRI is contraindicated) 4, 5

Clinical Pearls

• The O'Brien test should be part of a systematic shoulder examination that includes inspection, palpation, range of motion assessment, strength testing, and stability evaluation 5
• A positive O'Brien test should be interpreted in the context of the patient's history, other physical examination findings, and imaging results
• The test may be positive in patients with other shoulder pathologies, including rotator cuff tears, which can coexist with labral tears 5
• False positives are common, particularly in patients with acromioclavicular joint pathology

Remember that while the O'Brien test is a useful clinical tool, it is most valuable when considered as part of a comprehensive shoulder evaluation rather than as a standalone diagnostic test.