PURPOSE OF REVIEW: Posterolateral rotatory instability of the elbow is a relatively rare finding in patients complaining of lateral elbow pain and/or instability. Debate about the causes and biomechanics involved in its occurrence has spurred numerous studies over the last few years. We review and comment here on the previous two years of research. RECENT FINDINGS: A new appreciation of the biomechanical forces across the lateral elbow has led to interesting findings over the last couple years. Deficiencies of the radial head and lateral soft tissues, once considered unimportant in maintaining stability, have been implicated as playing a major role in posterolateral rotatory instability. Attritional injuries, in addition to posttraumatic injuries, have also been cited as sources. New physical examination techniques have been described that can easily be performed in the office on awake, unanaesthetized patients; these tests offer increased sensitivity and ease of use. Studies regarding surgical techniques, as well as long-term outcome studies, have helped define the best way to treat posterolateral rotatory instability. SUMMARY: Posterolateral rotatory instability is a spectrum of injury that, though rare, should be considered in any patient noting persistent lateral elbow pain with activity. Excellent outcomes are possible with prompt diagnosis and appropriate surgical management.