“The diagnosis of posterolateral rotary instability remains a clinical one, with a combination of the history, active and passive apprehension tests, and examination of the elbow under anesthesia” (Charambous 276). When diagnosing posterolateral rotary instability of the elbow, the tell-tale sign is, while performing the lateral pivot-shift test, there is a sudden, palpable and visible reduction of the radiohumeral joint(5). This reduction happens at approximately forty degrees of elbow flexion, and feels like the elbow is locking or snapping back into place(7). These episodes of subluxation cause a prominence of the radial head, leading to a fairly significant decrease in range of motion at the elbow joint(17). Also, these “episodes of instability only occurred when the elbow was extended and the forearm supinated” (O’Driscoll 442) like, for example, reaching for a light-switch. A history of trauma and/or surgery to the lateral side of the elbow and pain with a valgus stress and external rotation of the forearm will also be present in an individual with PLRI. This instability can occur at any age or stage of life, as I observed from the study conducted by O’Driscoll, Bell, and Morrey when they stated, “the ages of the patients at the time of initial injury ranged from three to forty-two years” (O’Driscoll 441)(16). There are multiple tests that may be performed on a person to determine the presence of posterolateral rotary instability. The most accurate special test for this particular injury is called the lateral pivot-shift test. This test is performed while the athlete lay supine with his/her affected limb overhead and his/her forearm supinated(19). From this position, the athletic trainer would apply a valgus force/axial loading on the lateral ligament complex and begin to move from full extension into flexion. As stated earlier, a sudden reduction of the radial head will be felt/heard at approximately 40 degrees of elbow flexion if the test is positive. Also, to avoid a falsely positive result, the tester must perform this special test with the forearm pronated as well. A very important note to keep in mind: the patient must be under anesthesia to attain the most accurate results! In a patient who is not anesthetized, ask him/her to perform a push-up or push out of a chair with the forearms supinated and greater than shoulder width apart. Failure to perform either of these exercises is a positive sign of PLRI(5). A test very similar to the lateral pivot-shift test is the lateral pivot-shift apprehension test. The steps to this test are exactly the same as the lateral pivot-shift test, except the athlete is awake. If apprehension occurs than the test would be considered positive(20). A third way to test for posterolateral rotary instability is called the posterolateral rotary drawer test. The athlete is positioned supine with the affected arm overhead and the elbow flexed to forty degrees. From this position the athletic trainer applies an anteroposterior force to the radius and the ulna with the forearm externally rotated. If the forearm subluxates away from the humerus on the lateral side while pivoting on the intact medial ligaments, this is a positive test. Also, like the lateral pivot-shift test, general anesthesia should be administered to the patient while this test is performed(19). The active floor push-up sign is a fourth test for posterolateral rotary instability of the elbow, in which the athlete pushes off of the floor in a push-up position with his/her elbows flexed to ninety degrees. His/her forearms should be supinated with arms abducted. As the elbow extends, if apprehension occurs or if the radial head dislocates this would be a positive test. A fifth option to test for PLRI would be the chair sign. With this special test, the athlete is in a seated position with his/her elbows flexed to ninety degrees and with his/her forearms supinated and arms abducted. The
