A 35-year-old female presents to the orthopedic clinic with a 3-week history of pain and weakness in her right forearm following a fall on an outstretched hand. Examination reveals loss of pronation and supination, and swelling over the distal forearm. X-rays show a fracture of the distal third of the radius with dorsal displacement and widening of the distal radioulnar joint (DRUJ) space. The radial head is in normal position. What is the most likely diagnosis?

Explanation

## Diagnosis: Galeazzi Fracture ### Definition **Key Point:** A Galeazzi fracture is a fracture of the distal third of the radius (within the distal 5–8 cm) with an associated dislocation or instability of the distal radioulnar joint (DRUJ). **High-Yield:** The classic phrase is "fracture of the radius with dislocation of the ulna" — meaning the ulna head displaces dorsally relative to the sigmoid notch of the radius. ### Anatomical Basis - The distal third of the radius is the critical zone where the interosseous membrane and DRUJ stabilizers are most important - Fracture of the radius in this region disrupts the DRUJ articulation - The ulna head typically displaces **dorsally** (posteriorly) due to the pull of the extensor carpi ulnaris (ECU) and the loss of the volar radioulnar ligament support ### Clinical Presentation The patient typically presents with: - Pain and swelling over the distal forearm - Loss of pronation and supination (key finding) - Visible deformity of the wrist - Tenderness over the DRUJ - Prominence of the ulna head on the dorsal wrist **Clinical Pearl:** Loss of pronation and supination is a hallmark of Galeazzi fracture and distinguishes it from a simple Colles fracture, where these movements may be preserved initially. ### Comparison: Monteggia vs. Galeazzi | Feature | Monteggia | Galeazzi | |---------|-----------|----------| | **Bone fractured** | Ulna (proximal/middle third) | Radius (distal third) | | **Associated dislocation** | Radial head (anterior or posterior) | DRUJ (dorsal ulna head) | | **Mechanism** | Fall on flexed elbow, FOOSH | Fall on outstretched hand, wrist extension | | **Loss of motion** | Pronation/supination variable | Pronation/supination markedly limited | | **Frequency** | More common | Less common | ### Diagnostic Imaging - **AP and lateral wrist X-rays:** Visualize the radial fracture and DRUJ alignment - **Key finding:** Widening of the DRUJ space on AP view or dorsal displacement of the ulna head on lateral view - **CT scan:** May be useful to assess DRUJ congruity and associated soft-tissue injury **Mnemonic:** **GALEAZZI = Distal Radius fracture + DRUJ dislocation** (remember: "G" for distal, "A" for associated DRUJ) ### Management 1. **Closed reduction** of the DRUJ (rarely successful long-term) 2. **ORIF of the radius** with plate fixation (volar or dorsal plate depending on fracture pattern) 3. **DRUJ stabilization:** - If DRUJ remains unstable after radius fixation → percutaneous pinning across the DRUJ (K-wire or screw) - Immobilization in supination (to relax ECU and reduce dorsal displacement) 4. Post-operative immobilization for 4–6 weeks 5. Early mobilization once DRUJ is stable **Warning:** Missed or inadequately treated DRUJ dislocation leads to chronic instability, loss of pronation/supination, pain, and poor functional outcomes. ### Complications - Chronic DRUJ instability - Malunion with DRUJ subluxation - Loss of pronation and supination - Post-traumatic arthritis of the DRUJ - Extensor pollicis longus (EPL) rupture (late complication)