The lateral collateral ligament complex of the elbow consists of the radial collateral ligament (to the annular ligament), the lateral ulnar collateral ligament (LUCL — to the ulna), and the accessory lateral collateral ligament. The LUCL is the most important component — its disruption produces posterolateral rotatory instability (PLRI), the most common pattern of elbow instability, where the radius and ulna rotate posterolaterally relative to the humerus.
| Origin | Lateral epicondyle of the humerus |
|---|---|
| Insertion | Annular ligament, proximal ulna, and lateral ulnar surface via the LUCL |
| Actions | Elbow varus stability and posterolateral rotatory stability via the LUCL |
|---|
LUCL injury occurs from elbow dislocation, lateral epicondyle cortisone injection, or lateral elbow surgery. PLRI produces apprehension during the lateral pivot shift test — the elbow collapses into posterolateral subluxation as the examiner flexes the supinated forearm from full extension. LUCL reconstruction restores elbow stability with graft through bone tunnels.
LUCL disruption producing elbow subluxation during the pivot shift test managed with LUCL reconstruction.
