A 65-year-old woman presents to the emergency department with severe pain and swelling over the dorsal aspect of her right wrist following a fall on an outstretched hand (FOOSH). On clinical examination, there is a 'dinner fork' deformity. Which investigation is most appropriate to confirm the diagnosis and assess for associated injuries?

Explanation

## Investigation of Choice for Colles Fracture **Key Point:** Plain radiographs (AP, lateral, and scaphoid views) are the gold standard and investigation of choice for suspected Colles fracture. They are sufficient for diagnosis, classification, and assessment of associated injuries in the vast majority of cases. ### Why Plain Radiographs? 1. **Diagnostic accuracy**: The 'dinner fork' deformity is pathognomonic and easily visualized on lateral view. 2. **Cost-effective**: Readily available, rapid, and economical. 3. **Standard views**: - **Anteroposterior (AP)**: Assesses radial deviation, comminution - **Lateral**: Shows dorsal displacement and angulation (hallmark of Colles) - **Scaphoid view**: Rules out associated scaphoid fracture (10–15% of Colles fractures) ### Associated Injuries to Assess on Plain Radiographs | Finding | Significance | | --- | --- | | Radial styloid fracture | Barton fracture variant; affects stability | | Ulnar styloid fracture | Present in ~50% of Colles fractures; assess for DRUJ disruption | | Intra-articular extension | Determines operative vs. conservative management | | Scaphoid fracture | Requires separate immobilization | **High-Yield:** The **Barton fracture** (intra-articular fracture-dislocation of the radiocarpal joint) is a variant of Colles fracture and is also diagnosed on plain radiographs; it requires operative reduction. **Clinical Pearl:** Assess **Colles fracture parameters** on lateral radiograph: - Dorsal angulation (normally 11° volar; >20° dorsal = malposition) - Radial height (normally 11 mm; <8 mm = loss of height) - Radial inclination (normally 23°; <15° = loss of inclination) ### When Are Advanced Imaging Studies Needed? - **CT with 3D reconstruction**: Reserved for complex intra-articular fractures, comminution, or pre-operative planning for ORIF. - **MRI**: Not routinely indicated; used only to assess associated soft tissue injuries (ligament tears, triangular fibrocartilage complex [TFCC] injury) if clinical suspicion is high. - **Ultrasound**: Not a diagnostic tool for fracture confirmation; may assess soft tissue swelling. [cite:Rockwood & Green's Fractures in Adults Ch 9]