Posterolateral rotatory instability of the elbow

Posterolateral rotatory instability of the elbow is a recently described condition resulting from insufficiency of both the static lateral collateral ligament complex and the dynamic supporting muscular structures of the elbow. The lateral ulnar collateral ligament is the essential component of the lateral collateral ligament complex, linking the humerus and ulna and acting as the principle static restraint preventing external rotation of the ulna on the humerus, thus preventing posterolateral elbow instability. Ligament insufficiency permits the proximal ulna and the radial head to externally rotate posterior when the forearm is positioned is supination and slight flexion. Recent studies have characterized this condition as posterolateral instability of the elbow, and have portrayed the continuum that exist between posterior lateral rotatory instability and elbow dislocation. For patients whose instability symptoms persist despite conservative measures, repair or reconstruction of the lateral ligament complex may provide significant relief and functional improvement.