A 62-year-old woman falls on an outstretched hand while walking. X-ray shows a fracture of the distal radius with dorsal displacement and angulation of the distal fragment. Which is the most common type of distal radius fracture?

Explanation

## Most Common Distal Radius Fracture **Key Point:** Colles' fracture is the most common type of distal radius fracture, accounting for approximately 90% of all distal radius fractures. ### Defining Features of Colles' Fracture **High-Yield:** Colles' fracture is characterized by: 1. Fracture of the distal radius (within 2–3 cm of the wrist joint) 2. **Dorsal displacement** and dorsal angulation of the distal fragment 3. Associated ulnar styloid fracture (50–60% of cases) 4. Radial shortening 5. Loss of radial inclination ### Clinical Context **Clinical Pearl:** Colles' fracture is the classic "dinner fork" deformity on lateral X-ray — the dorsal angulation creates a characteristic silhouette. It typically occurs in elderly patients with osteoporosis following a fall on an outstretched hand (FOOSH injury). ### Comparison with Other Distal Radius Fractures | Fracture Type | Displacement | Mechanism | Frequency | Associated Injury | | --- | --- | --- | --- | --- | | **Colles'** | Dorsal + dorsal angulation | FOOSH in elderly | ~90% | Ulnar styloid fracture | | **Smith's** | Volar (reverse Colles') | FOOSH with flexed wrist | ~10% | Less common | | **Barton's** | Intra-articular dorsal or volar | High-energy trauma | Rare | Radiocarpal dislocation | | **Chauffeur's** | Radial styloid fracture | Direct blow to radial side | Rare | Scaphoid injury | **Warning:** Do not confuse Colles' fracture (dorsal displacement) with Smith's fracture (volar displacement). The mechanism and patient demographics differ — Smith's is less common and typically occurs in younger patients or with a different injury mechanism. ### Why Colles' is Most Common **Mnemonic:** **COLLES = Common Older Ligamentous Loss Elderly Styloid** — reflects the typical elderly osteoporotic patient with a simple FOOSH mechanism. The high frequency reflects: - Osteoporosis prevalence in elderly women - Protective reflex to fall on outstretched hand - Biomechanics of wrist extension during impact