A 7-year-old boy presents to the emergency department following a fall on an outstretched hand (FOOSH injury). Clinical examination reveals severe swelling over the anterior elbow, loss of elbow extension, and absent radial pulse. Which investigation is the most appropriate next step to confirm the diagnosis and assess vascular compromise?

Explanation

## Investigation of Choice for Supracondylar Fracture ### Clinical Context Supracondylar fractures of the humerus are the most common elbow fractures in children, typically occurring after a FOOSH injury. The clinical presentation of severe swelling, loss of extension, and absent radial pulse suggests a displaced fracture with potential vascular compromise. ### Why Plain Radiography is the Investigation of Choice **Key Point:** Plain radiographs (AP and lateral views) are the gold standard for diagnosis and classification of supracondylar fractures. They are: - Immediately available in the emergency setting - Sufficient to confirm fracture presence and displacement - Essential for Gartland classification (Types I, II, III) - Non-invasive and rapid - Allow assessment of fracture pattern and comminution ### Role of Vascular Assessment **Clinical Pearl:** While the absent radial pulse is concerning for vascular injury, the initial management priority is: 1. Confirm fracture diagnosis with plain radiographs 2. Assess fracture displacement and type 3. Reduce the fracture urgently (often restores perfusion) 4. Re-assess pulse after reduction If pulse remains absent post-reduction, then advanced imaging (Doppler ultrasound or CT angiography) is warranted. ### Why Other Investigations Are Not First-Line | Investigation | Limitation | |---|---| | **Doppler ultrasound** | Useful for vascular assessment but does NOT diagnose the fracture; requires plain films first | | **CT angiography** | Delays urgent fracture reduction; reserved for post-reduction vascular complications | | **MRI** | Time-consuming, not suitable for acute trauma; poor for bone detail in acute setting | **High-Yield:** The vascular status (pulse presence/absence) is a clinical finding, not an investigation finding. Plain radiographs guide fracture reduction, which is the definitive treatment for most vascular compromise in supracondylar fractures.