A 52-year-old man presents with pain and swelling over the volar aspect of his right wrist after a fall on a flexed wrist. Clinical examination reveals a 'garden spade' or 'spoon' deformity with volar displacement of the hand. Which investigation is most appropriate to confirm the diagnosis and differentiate this fracture from other wrist injuries?

Explanation

## Investigation of Choice for Smith Fracture **Key Point:** Smith fracture (reverse Colles fracture) is best diagnosed and characterized using **AP, lateral, and scaphoid radiographic views**. The lateral view is crucial for demonstrating the pathognomonic volar displacement and angulation. ### Clinical Presentation vs. Radiographic Confirmation While the 'garden spade' or 'spoon' deformity is clinically suggestive, radiographic confirmation and classification are essential for management planning. ### Radiographic Views and Their Role | View | Purpose | Key Finding in Smith Fracture | | --- | --- | --- | | **Lateral** | Primary diagnostic view | Volar (palmar) displacement and angulation of distal fragment | | **AP** | Assess radial deviation, comminution | Radial shortening, radial deviation | | **Scaphoid** | Rule out associated scaphoid fracture | Scaphoid fracture present in 5–10% of Smith fractures | **High-Yield:** Smith fracture is the **reverse of Colles fracture**: - **Colles**: Dorsal displacement (fall on extended wrist) - **Smith**: Volar displacement (fall on flexed wrist) ### Why All Three Views Are Necessary 1. **Lateral view** alone: Shows volar displacement but misses radial deviation and comminution visible on AP. 2. **AP view** alone: Misses the defining volar angulation and displacement. 3. **Scaphoid views**: Essential because associated scaphoid fractures (5–10% of Smith fractures) require separate immobilization and have high risk of nonunion/avascular necrosis. ### Classification of Smith Fracture Smith fractures are classified into three types based on intra-articular involvement: 1. **Type I (Extra-articular)**: Simple metaphyseal fracture; most common (~60%) 2. **Type II (Intra-articular)**: Fracture line extends into radiocarpal joint 3. **Type III (Barton-type)**: Fracture-dislocation with volar displacement of radiocarpal joint **Clinical Pearl:** Type III Smith fractures (volar Barton fractures) require operative reduction due to radiocarpal joint involvement and instability. ### When Are Advanced Imaging Studies Indicated? - **CT with 3D reconstruction**: Reserved for complex intra-articular fractures (Type II/III), severe comminution, or pre-operative planning for ORIF. - **MRI**: Not routinely used; indicated only if soft tissue injury (TFCC, ligament) is suspected and would alter management. [cite:Rockwood & Green's Fractures in Adults 9e Ch 9; Campbell's Operative Orthopaedics 13e Ch 53]