A 58-year-old woman with osteoporosis slips on wet floor and falls onto her outstretched left hand. X-rays of the wrist show a fracture of the distal radius with dorsal angulation and dorsal displacement of the distal fragment. The fracture is complete, and there is minimal comminution. The radial styloid is intact. Based on fracture pattern and mechanism, which classification best describes this injury?

## Distal Radius Fracture Classification Distal radius fractures are classified based on the direction of displacement and associated features. The mechanism, angulation, and displacement pattern are key to differentiation. ### Colles' Fracture - **Mechanism:** Fall on outstretched hand (FOOSH) with wrist in extension - **Displacement:** Dorsal displacement and dorsal angulation of distal fragment - **Radial styloid:** Intact - **Frequency:** Most common distal radius fracture (85–90% of cases) - **Age group:** Elderly patients with osteoporosis; also young patients with high-energy trauma - **Associated injury:** Ulnar styloid fracture in 50–60% of cases ### Smith's Fracture ("Reverse Colles'") - **Mechanism:** Fall on flexed wrist or direct blow to dorsal wrist - **Displacement:** Volar (palmar) displacement and volar angulation - **Radial styloid:** Usually intact - **Frequency:** 10–15% of distal radius fractures - **Age group:** Younger patients; less common in elderly ### Barton's Fracture - **Type:** Intra-articular fracture-dislocation - **Displacement:** Dorsal (Barton) or volar (reverse Barton) with carpal dislocation - **Mechanism:** High-energy trauma - **Key feature:** Involves the radiocarpal joint with displacement of carpus ### Chauffeur's Fracture - **Location:** Radial styloid only - **Mechanism:** Blow to radial side of wrist - **Associated injury:** Often accompanied by scaphoid fracture or ligamentous injury **Key Point:** The **dorsal displacement + dorsal angulation + FOOSH mechanism + intact radial styloid** is pathognomonic for **Colles' fracture**. ### Clinical Pearl Colles' fractures in elderly osteoporotic patients often have minimal comminution but heal with high rates of malunion (loss of reduction) if not properly immobilized or surgically stabilized. The "dinner fork" deformity is the classic clinical sign. **High-Yield:** The mechanism (FOOSH with extension) + dorsal displacement is the quickest way to identify Colles' fracture on exam and imaging. ### Comparison Table | Feature | Colles' | Smith's | Barton's | Chauffeur's | | --- | --- | --- | --- | --- | | Mechanism | FOOSH extension | FOOSH flexion / direct blow | High-energy trauma | Radial blow | | Displacement | Dorsal | Volar | Dorsal or volar | Radial styloid | | Radial styloid | Intact | Intact | Involved | Fractured | | Intra-articular | No | No | Yes (dislocation) | No | | Associated injury | Ulnar styloid | Ulnar styloid | Carpal dislocation | Scaphoid fracture | | Frequency | 85–90% | 10–15% | 5% | 3% | [cite:Rockwood & Green's Fractures in Adults 9e Ch 13]