title: Posterolateral rotatory instability of the elbow.
abstract: Posterolateral rotatory instability of the elbow is a three-dimensional displacement pattern of abnormal external rotatory subluxation of the ulna coupled with valgus displacement on the humeral trochlea. This pattern causes the forearm bones to displace into external rotation and valgus during flexion of the elbow. Injury to the lateral ulnar collateral ligament allows abnormal supination of the ulna on the humerus. The radial head, being locked in the sigmoid (radial) notch of the proximal ulna by the annular ligament, subluxates posterior to the capitellum. The abnormality is usually posttraumatic and presents with locking, snapping, clicking, catching, and recurrent dislocation of the elbow. The clinical diagnosis is suspected from history and confirmed by the physical examination, which includes the posterolateral rotatory instability test. This test often is best performed under fluoroscopy or general anesthesia. Usually the instability is managed with either a repair of the ligament or an isometric reconstruction using a tendon graft.
authors.affiliation: Department of Orthopaedic Surgery and Trauma, Royal Darwin Hospital, Northern Territory Clinical School, Flinders University of South Australia, Darwin, Northern Territory, Australia.
authors.forename: Janak A
authors.initials: JA
authors.lastname: Mehta
authors.forename: Gregory I
authors.initials: GI
authors.lastname: Bain
mesh_terms: D001182:Arthroscopy / Q000379:methods; D001696:Biomechanical Phenomena; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015601:Injury Severity Score; D004204:Joint Dislocations / Q000175:diagnosis / Q000601:surgery*; D007593:Joint Instability / Q000209:etiology / Q000517:prevention & control*; D008297:Male; D019637:Orthopedic Procedures / Q000379:methods*; D010147:Pain Measurement; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function; D012399:Rotation; D016896:Treatment Outcome; D000092464:Elbow Injuries