Emergent Care / Stabilization:

• Asses if the injured extremity is neurovascularly intact; if not, immediate reduction and surgical consultation are needed.
• Assess for signs of compartment syndrome. If present, emergency fasciotomy is needed.
• Pain control (reasonable use of narcotics).
• Nothing by mouth (NPO).

(See Best Tests, Management, and Therapy sections for further details.)

The terrible triad injury is a complex dislocation (dislocation with concomitant bony injury) of the elbow. Terrible triad injury includes a posterior elbow dislocation accompanied by a fracture of the radial head or neck and of the coronoid process of the ulna.

Causes / typical injury mechanism: Terrible triad injury is an acute injury. The most common mechanism of action is a fall on an outstretched hand (FOOSH), creating an axial load with mild elbow flexion, internal rotation of the humerus with valgus stress, and forearm supination. High-energy trauma can also lead to terrible triad but is less common than FOOSH.

Classic history and presentation:

• FOOSH
• High-impact sport injuries
• Falls from height
• High-impact trauma

Prevalence:

• Terrible triad injuries account for 10%-11% of all adult elbow fractures.
• No known differences in sex prevalence.
• Elbow injuries are more common in the elderly population.
• They are less common in the pediatric population.
• Up to 20% of elbow dislocations result in a concomitant fracture.

Pathophysiology: The mechanism of action described above leads to posterior elbow dislocation with an impaction fracture of the radial head or neck and a shear fracture of the coronoid process of the ulna. Disruption of soft tissue structures occurs in a lateral to medial progression and can include injury to any or none of the following: lateral collateral ligament (LCL), anterior joint capsule, medial collateral ligament (MCL), and common extensor and flexor-pronator tendons.

Grade / classification system:

• Ulnohumeral joint dislocation.
• Radial head or neck fracture.
• Coronoid fracture of ulna. Smaller fracture fragments off of the coronoid are more likely to be associated with terrible triad injuries.