33 Special Tests. One Sheet
All major ortho special tests across 6 body regions — shoulder, knee, hip, spine, elbow, wrist. One printable PDF for clinical placement.
| Also known as | Active compression test, O’Brien’s active compression test |
| Structures tested | Glenoid labrum (SLAP lesion); acromioclavicular (AC) joint |
| Patient position | Standing or seated, arm at 90° flexion, 10° adduction, full internal rotation |
| Positive sign | Pain or click in internal rotation that diminishes or disappears in external rotation |
| Sensitivity (SLAP) | ~47–67% (varies by study) |
| Specificity (SLAP) | ~37–55% (varies by study) |
What Is O’Brien’s Test?
O’Brien’s test — also called the active compression test — is an orthopedic shoulder examination used to screen for glenoid labral tears, specifically superior labrum anterior to posterior (SLAP) lesions, and acromioclavicular (AC) joint pathology. It was first described by O’Brien et al. in 1998.
The test applies a compressive load to the shoulder in two positions — full internal rotation and full external rotation — and uses the difference in pain response between the two to localize the source. Where the pain is felt (deep in the shoulder vs. at the top of the shoulder) further guides interpretation.
Anatomy: The Glenoid Labrum and SLAP Lesions
The glenoid labrum is a fibrocartilaginous ring that deepens the glenoid fossa and provides attachment for the glenohumeral ligaments and long head of biceps. A SLAP lesion is a tear of the superior labrum that begins posteriorly and extends anteriorly, involving the biceps anchor.
SLAP lesions are common in overhead athletes and can result from acute trauma (e.g., a fall on an outstretched hand) or repetitive overhead loading. Symptoms typically include deep shoulder pain, a catching or clicking sensation, and pain with overhead activities or resisted biceps loading.
Involved Structures
- Glenoid labrum — superior portion (SLAP lesion)
- Acromioclavicular (AC) joint — a common source of false positives
- Long head of biceps tendon — attached to the superior labrum; may contribute to symptoms
National Institute Of Arthritis And Musculoskeletal And Skin Diseases (NIAMS); SVG version by Angelito7, Public domain, via Wikimedia Commons
How to Perform O’Brien’s Test
Starting Position
Position the patient standing or seated. Bring the arm to 90° of forward flexion with the elbow fully extended. Adduct the arm approximately 10° across the body. Fully internally rotate the shoulder so the thumb points downward.
Phase 1 — Internal Rotation
With the arm in full internal rotation (thumb down), apply a downward force to the patient’s forearm while the patient resists. Note the presence, location, and intensity of any pain or clicking.
Phase 2 — External Rotation
Without repositioning the arm, fully externally rotate the shoulder so the palm faces upward (supinated). Apply the same downward force again while the patient resists. Compare the pain response to Phase 1.
Positive Sign and Interpretation
The test is considered positive when pain or clicking occurs in Phase 1 (internal rotation) and diminishes or disappears in Phase 2 (external rotation). The location of the pain helps distinguish the source:
| Pain location | Interpretation |
|---|---|
| Deep in the shoulder or “inside” the joint | Suggests glenoid labral pathology (SLAP lesion) |
| On top of the shoulder at the AC joint | Suggests acromioclavicular joint pathology |
| Pain in both positions equally | Non-specific; consider other sources (rotator cuff, biceps) |
| No pain in either position | SLAP lesion and AC joint pathology less likely |
Sensitivity and Specificity
| Metric | Value |
|---|---|
| Sensitivity (SLAP lesion) | ~47–67% across studies |
| Specificity (SLAP lesion) | ~37–55% across studies |
| Sensitivity (AC joint) | ~16–41% |
| Specificity (AC joint) | ~90–97% |
Values synthesized from Hegedus et al. (2008, 2012) systematic reviews of shoulder special tests. The original O’Brien et al. (1998) paper reported much higher accuracy (sensitivity 100%, specificity 98%), but subsequent independent studies with arthroscopic confirmation as the reference standard have consistently shown lower numbers.
The diagnostic accuracy for SLAP lesions is modest and variable. The test performs better for AC joint pathology, where its specificity is high — making it more useful for ruling in AC joint involvement when pain localizes to the top of the shoulder.
Clinical Considerations
- Don’t rely on it alone for SLAP: The test’s sensitivity and specificity for SLAP lesions are too variable for confident diagnosis in isolation. Use it as part of a cluster with Speed’s Test and the Anterior Slide Test to improve accuracy.
- AC joint utility is higher: When pain localizes clearly to the AC joint on top of the shoulder, a positive O’Brien’s is more meaningful. High specificity means a positive result substantially increases the likelihood of AC joint involvement.
- Common false positives: Rotator cuff tears, biceps tendinopathy, and subacromial impingement can all produce pain with Phase 1. Pain that does not change between phases is less likely to reflect labral or AC joint pathology specifically.
- Overhead athletes: SLAP lesions are common in this population. Clinical suspicion should remain high even with a negative test result — sensitivity is insufficient to rule out SLAP in high-risk patients.
- MRI arthrogram: When SLAP lesion is strongly suspected clinically, MRI arthrogram with contrast is the preferred imaging modality and significantly outperforms clinical examination alone.
Related Shoulder Tests
- Hawkins-Kennedy Test — Subacromial impingement; high sensitivity for ruling out impingement
- Speed’s Test — Biceps tendinopathy and SLAP lesion; often combined with O’Brien’s
- Anterior Slide Test (Kibler Test) — SLAP lesion; complements O’Brien’s in a diagnostic cluster
- Scarf Test (Cross Arm Adduction Test) — AC joint pathology; more specific than O’Brien’s for AC joint
Frequently Asked Questions
What does it mean if pain is worse in internal rotation but goes away in external rotation?
This is the classic positive O’Brien’s pattern. In full internal rotation (thumb down), the superior labrum and biceps anchor are loaded in a way that stresses a SLAP tear. When the arm is externally rotated, this loading is relieved and pain typically decreases. Pain that persists equally in both positions is less specific and may reflect other shoulder pathology.
Can O’Brien’s test diagnose a SLAP tear?
Not definitively. O’Brien’s test can raise or lower clinical suspicion for a SLAP lesion, but its diagnostic accuracy is too variable to confirm or rule out a SLAP tear on its own. MRI arthrogram remains the most accurate non-surgical diagnostic tool. Clinical examination is most useful when multiple tests are used together and interpreted alongside the patient’s history and mechanism of injury.
References
- O’Brien SJ, Pagnani MJ, Fealy S, McGlynn SR, Wilson JB. The active compression test: a new and effective test for diagnosing labral tears and acromioclavicular joint abnormality. Am J Sports Med. 1998;26(5):610–613.
- Hegedus EJ, Goode AP, Cook CE, et al. Which physical examination tests provide clinicians with the most value when examining the shoulder? Update of a systematic review with meta-analysis of individual tests. Br J Sports Med. 2012;46(14):964–978.
- Magee DJ. Orthopedic Physical Assessment. 6th ed. Elsevier; 2014.
Video Demonstration of O’Brien’s Test
video source: bigesor
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