O'Brien's Test: Purpose, Procedure, Interpretation, and Clinical Significance

What is the O'Brien's Test?

The O'Brien's Test, also known as the Active Compression Test, is a provocative physical examination maneuver primarily used to assess for superior labral anterior-posterior (SLAP) lesions of the shoulder joint, and less commonly, acromioclavicular (AC) joint pathology.

Purpose of the O'Brien's Test

The O'Brien's Test is a clinical assessment tool employed by healthcare professionals to help diagnose specific injuries within the shoulder complex. Its primary aim is to identify potential damage to the superior labrum, particularly SLAP lesions, which involve tears to the upper portion of the glenoid labrum where the biceps tendon originates. It can also help differentiate pain originating from the acromioclavicular (AC) joint.

Understanding SLAP Lesions: The glenoid labrum is a ring of cartilage that surrounds the glenoid (shoulder socket), deepening it and providing stability. A SLAP lesion is a tear that occurs where the long head of the biceps tendon attaches to the superior aspect of the labrum. These injuries are common in overhead athletes or can result from falls onto an outstretched arm.

The test works by placing specific stress on the superior labrum and the AC joint, provoking pain or symptoms if these structures are compromised. The differential response based on arm position helps distinguish between labral and AC joint pathology.

How to Perform the O'Brien's Test

The O'Brien's Test involves two distinct phases, comparing the patient's symptoms in different arm rotations. It is typically performed with the patient seated or standing.

Patient Position:

• The patient is seated or standing, facing the examiner.
• The affected arm is flexed forward to 90 degrees at the shoulder.
• The elbow is kept in full extension.
• The arm is adducted approximately 10-15 degrees across the body (towards the midline).

Examiner Action (Phase 1 - Pain Provocation):

1. Arm Position: The patient's shoulder is in 90 degrees of flexion, 10-15 degrees of horizontal adduction, and the elbow is extended.
2. Forearm Rotation: The examiner internally rotates the patient's forearm so that the thumb points downwards (full pronation).
3. Resistance: The examiner applies a downward force to the patient's distal forearm/wrist, and the patient is instructed to resist this force.
4. Observation: The examiner notes the presence, location, and intensity of any pain or clicking experienced by the patient.

Examiner Action (Phase 2 - Pain Relief/Confirmation):

1. Arm Position: The patient's shoulder and elbow position remain exactly the same as in Phase 1 (90 degrees flexion, 10-15 degrees horizontal adduction, extended elbow).
2. Forearm Rotation: The examiner externally rotates the patient's forearm so that the palm faces upwards (full supination).
3. Resistance: The examiner again applies a downward force to the patient's distal forearm/wrist, and the patient is instructed to resist this force.
4. Observation: The examiner notes any change in pain or symptoms compared to Phase 1.

Interpreting the Results

The interpretation of the O'Brien's Test relies on the comparison of symptoms between the two phases and the specific location of the pain.

• Positive Test for SLAP Lesion: A positive O'Brien's Test for a SLAP lesion is indicated if:

  • The patient experiences pain or a painful clicking/catching sensation within the shoulder joint during Phase 1 (thumb-down/pronated position).
  • This pain or clicking is then significantly reduced or completely eliminated during Phase 2 (palm-up/supinated position).
  • The pain is typically localized deep within the anterior or superior aspect of the shoulder.

• Positive Test for AC Joint Pathology: A positive O'Brien's Test for AC joint pathology is indicated if:

  • The patient experiences pain localized specifically over the acromioclavicular joint (the joint at the top of the shoulder where the collarbone meets the shoulder blade) during Phase 1 (thumb-down/pronated position).
  • Crucially, this AC joint pain persists or even increases during Phase 2 (palm-up/supinated position). The change in forearm rotation does not alleviate the AC joint pain.

It is critical for the examiner to ask the patient where exactly they feel the pain to correctly differentiate between a labral and an AC joint issue.

Clinical Significance and Limitations

While the O'Brien's Test is a widely used orthopedic special test, it's important to understand its place within a comprehensive diagnostic process.

• Diagnostic Accuracy: The O'Brien's Test has demonstrated varying levels of sensitivity and specificity in studies. While it can be helpful, it is not a definitive stand-alone diagnostic tool. Its accuracy can be influenced by the type and severity of the SLAP lesion, as well as the presence of other shoulder pathologies.
• False Positives/Negatives: Other conditions, such as biceps tendonitis, rotator cuff impingement, or even cervical spine issues, can sometimes produce similar pain patterns, leading to potential false positives. Conversely, some labral tears may not elicit a positive test.
• Inter-rater Reliability: The consistency of results between different examiners can sometimes vary, highlighting the importance of experienced practitioners.
• Comprehensive Assessment: A positive O'Brien's Test should always be interpreted in conjunction with a thorough patient history (mechanism of injury, symptoms), other physical examination findings (range of motion, strength, other special tests), and potentially diagnostic imaging such as Magnetic Resonance Imaging (MRI) or MR arthrogram for definitive diagnosis.

Who Should Perform This Test?

The O'Brien's Test, like other orthopedic special tests, requires a solid understanding of anatomy, biomechanics, and clinical interpretation. Therefore, it should only be performed by trained and qualified healthcare professionals. This includes:

• Physical Therapists (Physiotherapists)
• Orthopedic Surgeons
• Sports Medicine Physicians
• Chiropractors
• Athletic Trainers

Attempting to self-diagnose or perform this test without proper training can lead to misinterpretation, delayed appropriate treatment, or potentially exacerbate an existing injury. If you are experiencing shoulder pain or suspect a SLAP lesion or AC joint issue, consult with a healthcare professional for an accurate diagnosis and personalized treatment plan.