39 - Traumatic Elbow Ligamentous Injury

Abstract

Elbow stability comes from the congruity of the articular surfaces, ligamentous static stabilizers, and neuromuscular dynamic stabilizers. Medially there is greater bony stability than laterally, where the soft tissue stabilizers are more important. The elbow is the second most commonly dislocated joint in the body because of the long moment arm on either side of the joint, small articular surface, and short moment of the stabilizers. Acute ligament injury can occur from a variety of injury mechanisms that result in different patterns of soft tissue injury. In simple dislocation, two broad patterns of injury exist, a valgus hyperextension pattern resulting in the most common posterolateral dislocation and a valgus external rotation compression pattern leading to a posteromedial dislocation. In both, a spectrum of soft tissue injury is seen and the risk of recurrent instability appears to be greatest in those with both primary and secondary stabilizers avulsed. Isolated acute medial ligament injury can occur as a result of hyperextension of the elbow and the risk will vary between sports; likewise, the need for repair will depend on the functional demands of the individual. Lateral ligament injury may result in a posteromedial rotatory instability particularly if the common extensor origin is also involved, with reports of lateral elbow pain, locking, or stiffness. More subtle instability can occur as a result of posterolateral ligament avulsion with an intact lateral ligament complex. This may be associated with a bony avulsion or Osborne-Cotterill lesion. Elbow dislocation or subluxation with a coronoid fracture but intact radial head is a posteromedial rotatory fracture dislocation, an unforgiving injury that if mismanaged can result in rapid arthrosis with no simple salvage. This chapter reviews the anatomy, pathoanatomy, investigation, and management of the common patterns of acute elbow ligament injury.