Arthroscopic and open management of posterolateral rotatory instability of the elbow.

Posterolateral rotatory instability (PLRI) is the most common cause of residual instability following a simple elbow dislocation. PLRI may result from trauma or iatrogenic injury to the radial ulnohumeral ligament during treatment for other conditions, such as lateral epicondylitis. PLRI can be identified through a combination of history and physical examination, and confirmed with magnetic resonance imaging arthrography. Once diagnosed, surgery is necessary to correct persistent instability. Instability can be confirmed arthroscopically through several findings, including subluxation of the radial head on the capitellum and the arthroscopic "drive through sign of the elbow." Acute repairs, both open and arthroscopic, heal with excellent patient outcomes. In the chronic setting, graft reconstruction may be required. This report describes arthroscopic repair of the radial ulnohumeral ligament and open reconstruction with associated outcomes. A high index of suspicion is necessary to correctly diagnosis this condition in patients with lateral elbow pain and feelings of instability.