## Clinical Differentiation: Smith vs. Colles Fracture ### Mechanism and Deformity Direction **Key Point:** The **direction of the clinical deformity** (volar vs. dorsal) and the **mechanism of injury** are the primary clinical discriminators between Smith and Colles fractures. ### Comparative Table | Aspect | Colles Fracture | Smith Fracture | |--------|-----------------|----------------| | **Mechanism** | Fall on dorsiflexed wrist (FOOSH) | Fall on flexed wrist (reverse FOOSH) | | **Clinical deformity** | Dorsal prominence ("dinner fork") | Volar prominence ("garden spade") | | **Lateral X-ray angulation** | Dorsal angulation | Volar angulation | | **Typical age** | Elderly (osteoporotic) | Younger, high-energy trauma | | **Frequency** | 90% of distal radius fractures | 5–10% of distal radius fractures | | **Reduction technique** | Dorsal to volar (extension → flexion) | Volar to dorsal (flexion → extension) | ### Clinical Pearl **High-Yield:** The **volar (palmar) deformity with volar angulation on lateral X-ray** is the defining feature of Smith fracture. This is the reverse of Colles and results from a fall on a flexed wrist. The clinical appearance (loss of dorsal contour, volar prominence) is immediately recognizable and is the best bedside discriminator. ### Mnemonic **"Smith = Smile"** — The volar deformity looks like a smile (concave dorsally, convex volarly). **"Colles = Dinner Fork"** — The dorsal deformity resembles an upside-down dinner fork. ### Why This Matters While both are distal radius fractures, the direction of deformity determines: - The mechanism of injury (and thus associated injuries) - The reduction technique (opposite directions) - The immobilization position (opposite positions) - Prognosis and complications [cite:Rockwood & Green's Fractures in Adults Ch 11] 
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