Posterolateral rotatory instability of the elbow.

Posterolateral rotatory instability (PLRI) of the elbow is recurrent elbow instability caused by injury to the radial ulnohumeral ligament or lateral ulnar collateral ligament. Deficiencies of the radial ulnohumeral ligament and laxity of the lateral capsule allow the proximal radioulnar joint to rotate and the radial head to subluxate posteriorly when stressed. Whether isolated or in conjunction with other injuries, PLRI represents the initial stage in the pathology of the unstable elbow. The diagnosis of PLRI can be difficult because the provocative tests are challenging to perform. Diagnostic arthroscopy is an excellent tool to demonstrate this instability. Treatment options include bracing for acute injuries, and primary repair or reconstruction for chronic injuries. Although arthroscopic plication and repair have been as effective as open techniques, the clinician should be prepared for open reconstruction if needed.