Stand-Up Test| Posterolateral Instability

Posterolateral rotatory instability, abbreviated as PLRI is the most commonly encountered pattern of elbow instability.

PLRI typically occurs as a result of a fall on the outstretched arm, generating an axial load, valgus force, and an external rotational movement (torque) about the forearm with respect to the humerus. This causes the radial head and proximal ulna to subluxate posterolaterally away from the humerus in a rotatory fashion detaching or tearing the lateral collateral ligament complex in stage 1. In a more severe stage 2, the tissue disruption progresses anteriorly and posteriorly around the elbow to the medial side and in stage 3, the injury involves the medial collateral ligament or even the common flexor-pronator origin.

Regan et al. (2006) did a diagnostic study on the Stand-up test, which is also called the chair push-up test, and found a sensitivity of 88% with unknown specificity. For this reason, we give this test a questionable clinical value in practice.

The Stand-up test makes use of the patient’s body weight to create an axial load, and valgus torque at the elbow resulting in posterolateral subluxation of the elbow. In order to perform the test have your patient seated on a chair with armrests. His elbows are both in 90 degrees of flexion with abducted shoulders and the forearm supinated. Then ask the patient to push himself up from the chair.

This test is positive if the patient has apprehension, reports a sense of instability or lateral elbow pain or if actual dislocation of the radial head takes place.

Other common orthopedic tests for PLRI are:

• Elbow Pivot-Shift Test
• Posterolateral Rotatory Drawer Test
• Tabletop Relocation Test
• Prone Push-Up Test

Regan, W., & Lapner, P. C. (2006). Prospective evaluation of two diagnostic apprehension signs for posterolateral instability of the elbow. Journal of shoulder and elbow surgery, 15(3), 344-346.