This prospective study introduced the active compression test (the O'Brien test) for the shoulder. It aimed to distinguish superior labral tears from acromioclavicular joint pathology using arm position and where the patient localizes pain. 318 patients were examined to define the test's diagnostic accuracy.
When a patient localizes shoulder pain, make them show you where: "on top" points to the AC joint, "deep inside" points to the labrum. This single distinction drives the whole test.
The mechanism is worth understanding for boards. In internal rotation the greater tuberosity locks and loads the AC joint and the biceps tendon tensions the bicipital-labral complex. Supination unloads both, which is why pain should ease on the second pass.
The reported numbers are strikingly high because this is a single-institution study by the test's developer, tested against a surgical population enriched for pathology. Real-world specificity in later independent studies has been lower, so treat the O'Brien test as one part of a provocative exam battery, not a standalone confirmation.
Still, this is the test residents are expected to name and perform for suspected SLAP lesions.
This prospective study introduced the active compression test (the O'Brien test) for the shoulder. It aimed to distinguish superior labral tears from acromioclavicular joint pathology using arm position and where the patient localizes pain. 318 patients were examined to define the test's diagnostic accuracy.
When a patient localizes shoulder pain, make them show you where: "on top" points to the AC joint, "deep inside" points to the labrum. This single distinction drives the whole test.
The mechanism is worth understanding for boards. In internal rotation the greater tuberosity locks and loads the AC joint and the biceps tendon tensions the bicipital-labral complex. Supination unloads both, which is why pain should ease on the second pass.
The reported numbers are strikingly high because this is a single-institution study by the test's developer, tested against a surgical population enriched for pathology. Real-world specificity in later independent studies has been lower, so treat the O'Brien test as one part of a provocative exam battery, not a standalone confirmation.
Still, this is the test residents are expected to name and perform for suspected SLAP lesions.