In a Galeazzi fracture, which anatomical structure is invariably injured and must be assessed on imaging?

Explanation

## Galeazzi Fracture: Key Anatomical Injury **Key Point:** A Galeazzi fracture is **incomplete** without disruption of the distal radioulnar joint (DRUJ). The DRUJ injury is the defining feature that distinguishes it from a simple radial shaft fracture. ### Galeazzi Fracture Anatomy **Definition:** Fracture of the distal third of the radius (typically distal to the pronator quadratus insertion) with **mandatory** DRUJ dislocation or ligamentous disruption. ### The Inseparable Triad | Component | Details | |-----------|----------| | **Radial fracture** | Distal third (usually distal to pronator quadratus) | | **DRUJ disruption** | Ligamentous injury (triangular fibrocartilage complex [TFCC] tear) or ulnar head dislocation | | **Interosseous membrane** | Often partially disrupted in high-energy injuries | **High-Yield:** The DRUJ injury is **always present** in a true Galeazzi fracture. If the DRUJ is intact on imaging, the diagnosis should be questioned — it may be a simple radial fracture instead. **Clinical Pearl:** The DRUJ can be disrupted in three ways: 1. **Dorsal dislocation** of the ulnar head (most common) 2. **Tear of the TFCC** without visible dislocation 3. **Fracture of the ulnar styloid** (present in ~50% of cases) **Mnemonic:** **"Galeazzi = DRUJ Disaster"** — The distal radioulnar joint is the critical injury that makes a Galeazzi fracture a Galeazzi fracture. ### Why DRUJ Assessment Matters - **Missed DRUJ injury** → chronic instability, loss of pronation/supination, poor functional outcome - **Imaging requirement:** Pronated and supinated views of the wrist to detect subtle DRUJ subluxation - **Treatment implication:** DRUJ disruption often requires surgical reduction and stabilization (pinning, TFCC repair)