The lateral collateral ligament complex of the elbow includes the radial collateral ligament, the lateral ulnar collateral ligament, and the annular ligament. The lateral ulnar collateral ligament is the most critical component, preventing posterolateral rotatory instability where the radial head subluxes posterolaterally from the capitellum. Iatrogenic disruption during elbow surgery is a recognised cause of this instability.
| Origin | Lateral epicondyle of the humerus |
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| Insertion | Annular ligament of the radius and ulna |
| Actions | Resists varus stress at the elbow; prevents posterolateral rotatory instability of the radial head |
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Posterolateral rotatory instability from lateral collateral ligament complex disruption produces a characteristic elbow giving way during activities with the forearm supinated and the elbow near extension, confirmed by the lateral pivot shift test of the elbow. It is the most common chronic elbow instability pattern and is often iatrogenic from excessive lateral epicondyle cortisone injection or surgical releases for lateral epicondylalgia.
Disruption producing posterolateral rotatory instability of the elbow, confirmed by the lateral pivot shift test and managed with surgical ligament reconstruction for functional instability.
