Video 9.4. O’Brien’s Active Compression Test

The examiner performs the active compression test on a patient with acromioclavicular joint pathology. The patient’s right shoulder is placed in 90 degrees of forward elevation with the elbow fully extended. The arm is then adducted 10 to15 degrees. First, the forearm is supinated with the thumb pointing to the ceiling. In this position, the examiner exerts an inferiorly directed force to the arm while the patient exerts resistance. Next, the forearm is pronated with the thumb pointing to the floor. In this position, the examiner again exerts an inferiorly directed force to the arm while the patient resists. A test result is considered positive if pain increases when the forearm is pronated (second position) and is relieved when the arm is supinated (first position). A positive test is suggestive of a superior labrum anterior to posterior (SLAP) tear if the pain is felt in the glenohumeral joint or acromioclavicular joint pathology if the location of pain is at the AC joint. Here, the patient has a positive right-sided active compression test.