A 68-year-old postmenopausal woman with osteoporosis trips on a staircase and falls directly onto her outstretched left hand. She presents with wrist pain and swelling. X-ray of the left wrist shows a fracture of the distal radius with dorsal displacement and angulation of the distal fragment. The fracture line is transverse and located approximately 2 cm proximal to the wrist joint. There is associated fracture of the ulnar styloid process. What is the most likely classification of this fracture?

Explanation

## Distal Radius Fracture Classification ### Clinical Presentation Analysis The patient is a postmenopausal woman with osteoporosis (risk factor for fragility fractures) who fell on outstretched hand (FOOA). The X-ray findings show: - **Distal radius fracture** (metaphyseal, within 2–3 cm of wrist joint) - **Dorsal displacement and dorsal angulation** of the distal fragment - **Transverse fracture line** - **Associated ulnar styloid fracture** These findings are pathognomonic for a **Colles fracture**. ### Distal Radius Fracture Classification Table | Fracture Type | Mechanism | Distal Fragment Position | Associated Injuries | Classic Deformity | |---|---|---|---|---| | **Colles** | FOOA with wrist extended | **Dorsal displacement + dorsal angulation** | Ulnar styloid fracture (50–60%) | "Dinner fork" deformity | | Smith | FOOA with wrist flexed OR direct blow to dorsum | **Volar displacement + volar angulation** | Anterior wrist dislocation (rare) | "Reverse dinner fork" | | Barton | FOOA with wrist flexed | **Intra-articular with volar displacement** | Wrist dislocation | Fracture-dislocation | | Chauffeur | Direct blow to radial side | **Radial styloid fracture** | Scaphoid injury (common) | Radial-sided wrist pain | **Key Point:** The **"dinner fork" deformity** (dorsal prominence of distal fragment) is the hallmark of Colles fracture. This occurs because the distal fragment is displaced dorsally and dorsally angulated. ### High-Yield Facts **High-Yield:** Colles fracture is the most common distal radius fracture, accounting for ~90% of all distal radius fractures. It is classically seen in elderly women with osteoporosis after a FOOA injury. **Mnemonic: COLLES = Dorsally displaced** — Remember that in Colles, the distal fragment goes **dorsally** (backward), creating the dinner fork appearance when viewed from the side. ### Clinical Pearl The associated **ulnar styloid fracture** in 50–60% of Colles fractures is due to the mechanism of injury and the pull of the ulnar collateral ligament. This does not change the classification but is an important associated finding. ### Management Considerations 1. Closed reduction under appropriate anesthesia 2. Immobilization in a below-elbow cast or splint 3. Assess for complications: median nerve compression, posterior interosseous nerve (PIN) injury, compartment syndrome 4. Monitor for malunion and loss of reduction 5. Early mobilization after union to prevent stiffness