Elbow dislocation

Musculoskeletal

Elbow dislocations are the third most common dislocation after shoulders and fingers. Ninety percent are posterior and due to a fall on an extended, abducted arm. Clinically, the elbow is flexed at 45° and usually quite swollen. The posteriorly dislocated olecranon process is easily palpated in its abnormal position.

Simple dislocations are treated with closed reduction and brief immobilization. Postreduction images should be carefully evaluated for radial head fracture, coronoid process fracture, or intra-articular bone fragments; CT may be helpful for operative planning in complex dislocations and in cases with comminuted fractures.

The “terrible triad” refers to elbow dislocation with associated fractures of the ulnar coronoid process and radial head. In this injury, the lateral collateral ligament is almost always disrupted, resulting in an unstable elbow. It is generally managed surgically by reattaching the ulnar coronoid process and affixing the radial head fracture (or replacing the radial head).

Posterior elbow dislocation. The ulna is dorsally dislocated with respect to the humerus, and the trochlea contacts the base of the coronoid process. A triangular fragment anterior to the distal humeral metaphysis corresponds to the fractured coronoid process tip. The radial neck is impacted, and the radial head is fractured and volarly angulated. A large joint effusion and marked soft tissue swelling are present. These findings correspond to a “terrible triad injury.”

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Complex and unstable elbow fracture/dislocations require operative treatment. They are more likely to be complicated by osteoarthritis, range of motion limitation, instability, and recurrent dislocation.

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