Evaluation and Management of Posterolateral Rotatory Instability (PLRI)

Abstract

Posterolateral rotatory instability (PLRI) describes a pattern of ligamentous instability in which the proximal ulna and radial head externally rotate about the distal humerus when the forearm is positioned in supination and slight flexion. Insufficiency of both the static ligamentous stabilizers and the dynamic stabilizers of the posterolateral elbow is accepted as the cause with the lateral ulnar collateral ligament (LUCL) as the main static stabilizing component. This ligament originates at the lateral epicondyle and inserts onto the supinator crest. PLRI is generally considered in a continuum of stages ranging from minor laxity to recurrent elbow dislocations. Initial treatment is conservative. If the instability symptoms persist after adequate conservative treatment, surgical treatment can be considered. Invasive treatment varies from direct repair to the reconstruction of the lateral ligamentous complex. This chapter discusses the background, history and treatment of PLRI focusing on the diagnostic and surgical techniques.