Elbow Dislocations — Terrible Triad

The terrible triad injury of the elbow is a severe and unstable injury pattern consisting of elbow dislocation associated with fractures of the radial head and the coronoid process of the ulna. This injury pattern is called the “terrible triad” because it historically carried poor outcomes due to persistent instability, stiffness, and post-traumatic arthritis.

Modern surgical techniques and improved understanding of elbow biomechanics have significantly improved outcomes. Treatment typically involves surgical stabilization including fixation or replacement of the radial head, repair of the coronoid fracture, and reconstruction of the lateral collateral ligament complex.

The elbow joint is composed of three articulations:

• Humeroulnar joint
• Humeroradial joint
• Proximal radioulnar joint

Stability of the elbow is maintained by both bony and ligamentous structures.

• Coronoid process – anterior bony stabilizer
• Radial head – secondary valgus stabilizer
• Lateral collateral ligament (LCL) complex
• Medial collateral ligament (MCL)

In terrible triad injuries, disruption of these structures leads to severe instability of the elbow joint.

• Fall on outstretched hand
• Axial load applied to forearm
• Valgus force combined with supination
• Posterolateral rotatory instability mechanism

This mechanism produces sequential failure of stabilizing structures leading to elbow dislocation and associated fractures.

• Severe elbow pain
• Swelling and deformity
• Limited elbow motion
• Instability of the joint
• Possible neurovascular compromise

A careful neurovascular examination is essential to identify injury to the ulnar, median, or radial nerves.

• AP and lateral radiographs of elbow
• CT scan for fracture evaluation
• 3D CT reconstruction for surgical planning

CT imaging is particularly helpful in identifying the extent of coronoid and radial head fractures.

The primary goal of treatment is to restore elbow stability and allow early motion to prevent stiffness.

• Early controlled mobilization
• Physiotherapy for range of motion
• Avoid prolonged immobilization
• Gradual strengthening exercises

• Elbow stiffness
• Recurrent instability
• Post-traumatic arthritis
• Heterotopic ossification
• Ulnar nerve injury

• Terrible triad = elbow dislocation + radial head fracture + coronoid fracture
• Mechanism usually posterolateral rotatory instability
• Most cases require surgical treatment
• Early motion is critical to prevent stiffness