Then he/she forward flexes his or her arm to 90 degrees,
With the arm in 10 degrees of adduction across the body, and maximum internal rotation (pronate the forearm) so the thumbs pointing downward.
The examiner attempts to press the arm downward against the patient’s resistance.
The test is then repeated in maximum external rotation (forearm supination) while the examiner press the arm downward against resistance.
What does a positive O’Brien Test mean?
The test is positive where the first phase elicits pain that then lessens or disappears in forearm supination (maximum external rotation).
Sensitivity & Specificity
A study by J. Matthew Owen 2 shows that O’Brien test has a high Sensitivity and Specificity for detecting a SLAP tear, as following:
Sensitivity: 100 %
Specificity: 98 %
It also suggests that the O’Briens test has a high sensitivity (83%) and highly predictive (90%) of posterior labral injury.
Another study by William B Stetson 3 found that the O’Brien and Crank tests were not sensitive clinical indicators for detecting glenoid labral tears and other tears of the anterior and posterior labrum (O’Brien test has a Sensitivity of 54 %, and Specificity of 31 %).
It is crucial to inquire about the location of the pain as the O’Brien test can also yield positive results in the presence of acromioclavicular joint disorders.
Pain reported within the shoulder suggests a SLAP lesion (Superior Labrum Anterior and Posterior injuries), whereas pain over the acromioclavicular joint may also be due to osteoarthritis of the acromioclavicular joint.
SLAP lesion (Superior Labrum Anterior and Posterior injuries) can results from compressive loading of the shoulder in the flexed abducted position (for example, in a fall on the outstretched hand). The injury of the superior labrum begins posteriorly and extends anteriorly, stopping before or at the mid-glenoid notch and including the ‘anchor’ of the biceps tendon to the labrum.
There are four main types described:
non-traumatic superior labral degeneration, usually in older people and often asymptomatic.
Avulsion of the superior part of the labrum, the most common type.
A ‘bucket handle’ tear of the superior labrum.
As for type 3 with an extension into the tendon of Long Head of Biceps.
Very few patients with SLAP lesion injuries return to full capability without surgical intervention. Arthroscopic repair of an isolated superior labral lesion is successful in the large majority (91%) of patients. However, the results in patients who participate in overhead sports are not as satisfactory as those in patients who are not involved in overhead sports. Simple lesions are simply debrided. In more significant detachments the labrum is either repaired or excised with a tenotomy or tenodesis of the biceps.
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. PMID: 9784804
J. Matthew Owen, Thomas Boulter, Mike Walton, Lennard Funk, and Tanya Anne Mackenzie. Reinterpretation of O’Brien test in posterior labral tears of the shoulder. Int J Shoulder Surg. 2015 Jan-Mar; 9(1): 6–8. PMCID: PMC4325388
Stetson WB, Templin K. The crank test, the O’Brien test, and routine magnetic resonance imaging scans in the diagnosis of labral tears. Am J Sports Med 2002;30(6):806–809. PMID: 12435645.
Clinical Tests for the Musculoskeletal 3rd Ed. Book
Apley and Solomon’s System of Orthopaedics and Trauma 10th Edition