SLAP lesions occur at the site where the biceps tendon attaches to the superior labrum. The injury occurs when the superior labrum tears off the glenoid attachment. SLAP lesions place strain on the anterior band of the inferior glenohumeral ligament, which compromises shoulder stability. In patients younger than 40 years of age, SLAP lesions can develop from repetitive overhead sports activities or as a result of falling on an outstretched hand, which pulls on the biceps anchor on the labrum. In patients older than 40 years of age, SLAP lesions may occur occur over time and are generally considered a degenerative condition.
The O’Brien test, also known as the active compression test, is commonly used to diagnose SLAP tears. The test involves placing the arm in 90 degrees of forward flexion, 20 degrees of horizontal adduction, and internal rotation (thumb pointing down). The patient is then instructed to forward flex the arm against resistance. The test is repeated with the arm internally rotated and then externally rotated. A positive test score achieved with pain with internal rotation but not external rotation. The O’Brien test stresses the labrum by tightening the posterior capsule and posteriorly translating the humeral head. This stress causes pain and weakness when the superior labrum is torn. Magnetic resonance arthrogram is the diagnostic study of choice for SLAP tears. The figure shows the arthrogram dye underneath and into the superior labral tear.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).
- Owen M, Boulter T, Walton M, Funk L, Mackenzie T. Reinterpretation of O’Brien test in posterior labral tears of the shoulder. Int J Shoulder Surg. 2015;9(1):6-8.
- Camp C, Marx R. Clinical summary: labral tears of the shoulder. JBJS website. https://www.jbjs.org/summary.php?id=156. Accessed January 14, 2019.