A 68-year-old woman falls on her outstretched hand while slipping on wet floor at home. She presents to the emergency department with severe pain and swelling over the dorsal aspect of the wrist. On examination, the wrist shows a characteristic 'dinner fork' deformity. X-ray confirms a fracture of the distal radius with dorsal displacement and dorsal angulation of the distal fragment. Which of the following is the most likely diagnosis?

Explanation

## Diagnosis: Colles Fracture ### Clinical Presentation The patient presents with the classic mechanism and clinical findings of a Colles fracture: - **Fall on outstretched hand (FOOSH)** — the classic injury mechanism - **Dorsal displacement and dorsal angulation** of the distal radial fragment - **'Dinner fork' deformity** — pathognomonic appearance on clinical examination and X-ray ### Key Radiological Features | Feature | Colles Fracture | Smith Fracture | |---------|-----------------|----------------| | **Mechanism** | FOOSH with wrist extension | FOOSH with wrist flexion | | **Distal fragment displacement** | Dorsal (posterior) | Volar (anterior) | | **Angulation** | Dorsal angulation | Volar angulation | | **Clinical deformity** | Dinner fork | Reverse dinner fork (spoon) | | **Frequency** | 90% of distal radius fractures | 5–10% of distal radius fractures | | **Age group** | Elderly (osteoporotic bone) | Younger patients, high-energy trauma | **Key Point:** The 'dinner fork' deformity is the hallmark of Colles fracture and results from dorsal displacement of the distal radial fragment. ### Colles Fracture — Definition A fracture of the distal radius (within 2–3 cm of the wrist joint) with: 1. Dorsal displacement of the distal fragment 2. Dorsal angulation (typically 10–20°) 3. Often associated with an ulnar styloid fracture (50–60% of cases) **High-Yield:** Colles fracture is the most common fracture in elderly patients presenting to the emergency department, accounting for ~90% of all distal radius fractures. ### Associated Complications - Posterior interosseous nerve (PIN) compression - Extensor pollicis longus (EPL) rupture (late complication) - Malunion with loss of radial height, radial inclination, or volar tilt - Post-traumatic arthritis of the wrist **Clinical Pearl:** The mechanism of injury (wrist extension during fall) determines the direction of displacement — extension forces drive the distal fragment dorsally, creating the dinner fork appearance.