O’Brien’s Active Compression Test

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 3 min read
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O'Brien's Active Compression Test is to indicate potential labral (SLAP Lesion) or acromioclavicular lesions as a cause of shoulder pain. O'Brien's active compression test was primarily developed for the assessment of Acromioclavicular joint pathology following a patient's demonstration of what reproduced their shoulder pain. O'Brien...

For severe symptoms, danger signs, pregnancy, child illness, or sudden worsening, seek urgent medical care.

বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

এই তথ্য শিক্ষা ও সচেতনতার জন্য। এটি ডাক্তারি পরীক্ষা, রোগ নির্ণয় বা প্রেসক্রিপশনের বিকল্প নয়।

Article Summary

O'Brien's Active Compression Test is to indicate potential labral (SLAP Lesion) or acromioclavicular lesions as a cause of shoulder pain. O'Brien's active compression test was primarily developed for the assessment of Acromioclavicular joint pathology following a patient's demonstration of what reproduced their shoulder pain. O'Brien noted in a series of patients it was also excellent for detecting labral pathology. Test The patient is instructed to...

Educational health guideWritten for patient understanding and clinical awareness.
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Emergency safety firstUrgent warning signs are highlighted below.

Seek urgent medical care if you notice

These warning signs are general safety guidance. Local emergency numbers and clinical judgment should always come first.

  • Severe symptoms, breathing difficulty, fainting, confusion, or rapidly worsening illness.
  • New weakness, severe pain, high fever, or symptoms after a serious injury.
  • Any symptom that feels urgent, unusual, or unsafe for the patient.
1

Emergency now

Use emergency care for severe, sudden, rapidly worsening, or life-threatening symptoms.

2

See a doctor

Book a professional medical evaluation if symptoms persist, worsen, recur often, affect daily activities, or occur in a high-risk patient.

3

Learn safely

Use this article to understand possible causes, tests, treatment options, prevention, and questions to ask your clinician.

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Definition

O’Brien’s Active Compression Test is to indicate potential labral (SLAP ulcer. সহজ বাংলা: শরীরের অস্বাভাবিক দাগ, ক্ষত বা ফোলা অংশ।" data-rx-term="lesion" data-rx-definition="A lesion is an abnormal area of tissue such as a spot, wound, patch, lump, or ulcer. সহজ বাংলা: শরীরের অস্বাভাবিক দাগ, ক্ষত বা ফোলা অংশ।">Lesion) or acromioclavicular lesions as a cause of shoulder pain. O’Brien’s active compression test was primarily developed for the assessment of Acromioclavicular joint pathology following a patient’s demonstration of what reproduced their shoulder pain. O’Brien noted in a series of patients it was also excellent for detecting labral pathology.

Test

The patient is instructed to flex their arm to 90° with the elbow fully extended and then adduct the arm 10-15°medial to the sagittal plane. The arm is then maximally internally rotated and the patient resists the examiner’s downward force. The procedure is repeated in supination. The O’Brien Test is designed to maximally load and compress the ACJ and superior labrum. For maximal results, the authors stress that the patient should resist the examiner’s downward force rather than the examiner resisting forward flexion.

Positive

Pain elicited by the fIrst maneuver is reduced or eliminated by a second.

ACJ pain =ACJ
Pain or clicking deep in the GHJ = labral

Arthroscopy revealed that the test position (90° forward flexion, 10-15° adduction, and maximum internal rotation) displaces the biceps tendon medially and inferiorly, therefore, putting tension on the bicipitallabral complex. A secondary shear is created in the glenoid and labrum. In an unstable SLAP ulcer. সহজ বাংলা: শরীরের অস্বাভাবিক দাগ, ক্ষত বা ফোলা অংশ।" data-rx-term="lesion" data-rx-definition="A lesion is an abnormal area of tissue such as a spot, wound, patch, lump, or ulcer. সহজ বাংলা: শরীরের অস্বাভাবিক দাগ, ক্ষত বা ফোলা অংশ।">lesion tension from the biceps tendon from this shear, compression from the capsular windup, or both creates an internal mechanical derangement and displacement that accounts for the painful clicking that patients experience. For a positive test, the patient MUST report a significant decrease in symptomology in the supination test position. Cadaver studies (Parentis et al 2004) have clarified contact between the lesser tuberosity, subscapularis tendon, and superior aspect of the glenoid and labrum in the internally rotated position.

Cadaver studies examined the anatomical basis of the ACJ component of the test. They revealed that the highest compressive pressure was generated in the test position. The greater tuberosity elevates the relatively depressed acromion and locks and loads the ACJ. Full supination relaxed the joint by virtue of the greater tuberosity moving out of the way.

The following results are based on O’Brien’s prospective study of 268 patients.

Sensitivity   Specificity    NPV
Labral   100% 98.5% 100%
ACJ   100%  96.6%  100%

Research

Compared to:

Sensitivity    Specificity    NPV
Stetson (2002)    54%  31%  50%!
Guanche (2003) (For Labral)   63%  73%
Chronopoulos E(2004) (For ACJ)    41%  95%  >94%

 

References

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Which doctor may help?

Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

  • Write when the problem started and how it changed.
  • Bring old prescriptions, investigation reports, and current medicines.
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Questions to ask

  • What is the most likely cause of my symptoms?
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Tests to discuss

  • Vital signs: temperature, pulse, blood pressure, oxygen saturation
  • Basic physical examination by a clinician
  • CBC, urine test, blood sugar, or imaging only when clinically needed

Avoid these mistakes

  • Do not use antibiotics, steroid tablets/injections, or strong painkillers without proper medical advice.
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  • Do not delay emergency care when danger signs are present.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

  • Rest, drink safe water, and observe symptoms carefully.
  • Keep a written note of symptoms, duration, temperature, medicines already taken, and allergy history.
  • Seek medical care quickly if symptoms are severe, worsening, or unusual for the patient.

OTC medicine safety

  • For mild pain or fever, ask a registered pharmacist or doctor before using common over-the-counter pain/fever medicines.
  • Do not combine multiple pain medicines without advice, especially if you have kidney disease, liver disease, stomach ulcer, asthma, pregnancy, or take blood thinners.
  • Do not give adult medicines to children unless a qualified clinician advises it.

Avoid these mistakes

  • Do not start antibiotics without a proper medical decision.
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  • Do not delay emergency care because of home remedies.

Get urgent help if

  • Severe symptoms, confusion, fainting, breathing difficulty, chest pain, severe dehydration, or sudden weakness need urgent medical care.
Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

Patient health record and symptom diary

Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Doctor / qualified healthcare provider
Tests to discuss with doctor
  • Basic vital signs: temperature, pulse, blood pressure, oxygen level if needed
  • Relevant blood, urine, imaging, or specialist tests only after clinical assessment
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
  • Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Safe pathway to proper treatment

Care roadmap for: O’Brien’s Active Compression Test

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

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Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area from the RX Article Professional Blocks panel.

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