Surgeon Experience Level Affects Mechanics of the Pivot Shift Test for Posterolateral Rotatory Instability of the Elbow

Posterolateral rotatory instability (PLRI) of the elbow occurs secondary to an injury to the lateral ulnar collateral ligament and lateral stabilizing structures [2]. The lateral pivot-shift test (PST) is a clinical examination for diagnosing PLRI [1]. The test involves moving the elbow from full extension to flexion while applying simultaneous supination torque, valgus moment, and axial compression [2]; a positive result is characterized by ulnohumeral subluxation that is seen clinically as posterolateral movement of the radial head and an incongruent radiocapitellar joint [2]. The PST is difficult to reliably reproduce in an office setting [3]. This can be due to patient-guarding or inexperience of the examiner. It is likely that the experienced examiner may perform the test differently from the inexperienced examiner. The PST has not previously been characterized biomechanically in the laboratory. Thus, the objective of this study is to fully characterize the biomechanics of the PST for PLRI. We will evaluate the repeatability of the PST across multiple surgeons and determine how the clinician’s level of training affects their method of testing. These results will be useful in developing training guidelines to standardize PST application as well as to improve accuracy.