A review of Terrible Triad injuries: Ortho Reviews - Flashcard

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Terrible triad injuries are complex posterior elbow dislocations associated with coronoid and radial head fractures as well as capsular and ligamentous injuries.

These injuries commonly result from a fall on an outstretched arm and the structures of the elbow fail from lateral to medial.

LCL --> anterior capsule --> MCL

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Contributions to elbow stability:
The radial head provides an anterior/valgus buttress.
The coronoid provides an anterior/varus buttress.

The LCL provides varus/posterolateral rotary stability.
The MCL provides valgus/posteromedial rotary stability.

Components of the LCL:
Ulnar Collateral Ligament **
Radial Collateral Ligament
Accessory Collateral Ligament
Annular Ligament

Components of MCL:
Anterior Bundle **
Posterior Bundle
Transverse Bundle

** Most important for Stability

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Morrey Classification System of coronoid fractures:
1: Coronoid tip avulsion
2: <50% of Coronoid
3: >50% of Coronoid

Type 3 injuries are associated w/ posterolateral instability

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Mason Classification System of radial head fractures:
1: < 2mm displacement
2: > 2mm displacement
3: comminuted
4: fractures associated with elbow dislocation

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Terrible triad injuries require surgical fixation in almost all cases and are addressed in a stepwise approach.

1) ORIF vs radial head replacement
2) ORIF of coronoid if > 10% involved
3) Repair of the LCL

After these three steps you should assess elbow stability under fluoro.

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If the elbow remains unstable consider repairing the MCL.

If the elbow still remains unstable after repair of the MCL consider an internal fixator such as an IJS (shown below) or external fixation.

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Patients should be immobilized following surgery, with supervised motion beginning at the surgeon's preference.

Immobilization positioning:
MCL intact, LCL repaired: 90° in full pronation to reduce posterolateral instability

MCL and LCL repaired: 90° in neutral rotation.

Complications include:
Continued instability
Hardware failure
Stiffness from immobilization
Post-traumatic arthritis.

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Ortho Reviews - Terrible Triad Injuries