A 28-year-old male construction worker presents to the emergency department following a fall onto his outstretched left arm while working at height. He reports severe pain in the proximal forearm with visible deformity. On examination, the elbow is swollen and tender, with the radial head appearing prominent anteriorly. X-rays reveal a fracture of the proximal third of the ulna with anterior displacement of the radial head. What is the most appropriate initial management?

Explanation

## Monteggia Fracture-Dislocation: Definition and Management **Key Point:** A Monteggia fracture-dislocation consists of a fracture of the proximal or middle third of the ulna combined with an anterior dislocation of the radial head. This is a classic injury pattern that requires specific management. ### Classification (Bado) Monteggia fractures are classified into four types based on the direction of radial head displacement and location of the ulnar fracture: | Type | Ulnar Fracture Location | Radial Head Direction | Frequency | Mechanism | |------|------------------------|----------------------|-----------|----------| | I | Proximal/middle third | Anterior | 60% | Fall on outstretched hand with forearm flexion | | II | Middle/distal third | Posterior | 15% | Direct blow to posterior forearm | | III | Metaphyseal | Anterior | 20% | Fall on outstretched hand in children | | IV | Proximal third | Anterior | 5% | Rare; both radius and ulna fractured | **High-Yield:** Type I (anterior dislocation with proximal ulnar fracture) is the most common presentation and is what this case describes. ### Management Algorithm ```mermaid flowchart TD A["Monteggia Fracture-Dislocation Diagnosed"]:::outcome --> B{"Associated Injuries?<br/>Neurovascular compromise?<br/>Open fracture?"}:::decision B -->|"No complications"| C["ORIF of Ulna<br/>+ Closed Reduction of<br/>Radial Head"]:::action B -->|"Open fracture or<br/>vascular injury"| D["Urgent surgical<br/>intervention"]:::urgent C --> E["Immobilize in<br/>posterior slab<br/>90° flexion"]:::action E --> F["Early mobilization<br/>at 3-4 weeks"]:::action F --> G["Good functional<br/>outcome"]:::outcome ``` ### Why ORIF of the Ulna is Essential **Clinical Pearl:** Simply reducing the radial head dislocation without fixing the ulnar fracture will result in loss of reduction and poor functional outcomes. The radial head dislocation is a secondary finding—the primary pathology is the ulnar fracture. 1. **Anatomical reduction of the ulna** restores the interosseous space and allows the radial head to reduce spontaneously or with gentle manipulation. 2. **Plate fixation** (3.5 mm compression plate) is the gold standard for proximal and middle third ulnar fractures. 3. **Closed reduction of the radial head** is then performed after ulnar stabilization; it usually reduces easily once the ulna is properly aligned. 4. **Immobilization** in a posterior slab at 90° elbow flexion for 3–4 weeks, followed by early active mobilization. ### Why Closed Reduction Alone Fails **Warning:** Attempting to reduce the radial head dislocation without fixing the ulnar fracture is a common pitfall. The radial head will re-dislocate because the underlying structural deformity (the ulnar fracture) has not been corrected. ### Neurovascular Assessment - Check for **posterior interosseous nerve (PIN)** injury (dorsal interosseous nerve branch)—assess thumb and finger extension. - Assess radial and ulnar pulses; vascular injury is rare but requires urgent intervention. - Compartment syndrome can develop; monitor closely for pain out of proportion. **High-Yield:** The radial nerve is at risk during reduction and fixation; careful surgical technique is essential. [cite:Rockwood & Green's Fractures in Adults Ch 27]