## Monteggia Fracture: Definition & Classification **Key Point:** A Monteggia fracture is a fracture of the proximal or middle third of the radius combined with an anterior or posterior dislocation of the radial head. This is a classic injury pattern that must be recognized to avoid missing the radial head dislocation. ### Bado Classification | Type | Radial Fracture Location | Radial Head Dislocation | Frequency | Mechanism | |------|--------------------------|-------------------------|-----------|----------| | I | Proximal/middle third | Anterior | 60% | FOOSH, fall on extended elbow | | II | Middle/distal third | Posterior | 15% | Direct blow to posterior forearm | | III | Metaphyseal (distal radius) | Anterior | 20% | Fall on pronated hand | | IV | Radius + ulna both fractured | Anterior | 5% | High-energy trauma | **High-Yield:** Type I (anterior dislocation) is the most common and is the pattern described in this stem. ## Management Algorithm ```mermaid flowchart TD A["Monteggia Fracture Diagnosed"]:::outcome --> B{"Neurovascular Status?"}:::decision B -->|"Intact"| C["Closed Reduction under GA"]:::action B -->|"Compromised"| D["Urgent ORIF"]:::urgent C --> E["Reduce radial head dislocation first"]:::action E --> F["Then reduce radius fracture"]:::action F --> G["Immobilize in supination/extension"]:::action G --> H{"Fracture Stable?"}:::decision H -->|"Yes"| I["Above-elbow cast 6-8 weeks"]:::action H -->|"No"| J["ORIF with plate/screw"]:::action I --> K["Follow-up X-ray at 1-2 weeks"]:::action ``` ### Why Closed Reduction First? 1. **Anatomic reduction of the radius fracture** often reduces the radial head dislocation spontaneously (in ~70% of cases). 2. **Reduction sequence matters:** Always reduce the radial head dislocation FIRST, then reduce the radius fracture. 3. **Immobilization position:** The forearm must be immobilized in **supination** (not pronation) to maintain the reduced radial head position. **Clinical Pearl:** The key to successful closed reduction is achieving supination of the forearm. Pronation will re-dislocate the radial head. ### When to Proceed to ORIF - Neurovascular compromise requiring urgent decompression - Unstable fracture pattern after closed reduction - Associated fractures (e.g., coronoid process fracture in Type II) - Failure of closed reduction - Chronic unreduced Monteggia (rare) **Warning:** Missing the radial head dislocation is a common error. Always look for it on the lateral X-ray view. ## Rationale for Correct Answer With intact neurovascular status, closed reduction under general anesthesia is the gold standard first-line management. The radial head dislocation will often reduce with proper reduction of the radius fracture, and immobilization in supination maintains the reduction. [cite:Rockwood & Green's Fractures in Adults 9e Ch 27] 
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