A 58-year-old man presents with a fall on a flexed wrist. Clinical examination shows volar swelling and a 'garden spade' deformity of the left wrist. Plain radiographs confirm a volar displacement of the distal radius fragment. Which investigation is most appropriate to assess for intra-articular involvement and guide surgical management?

Explanation

## Investigation of Choice for Complex Smith Fracture Assessment **Key Point:** While plain radiography is the initial investigation, CT with 3D reconstruction is the investigation of choice for assessing intra-articular involvement and complex fracture patterns in Smith fractures requiring surgical intervention. ### Smith Fracture: Clinical Context A Smith fracture is a volar (flexion) fracture-dislocation of the distal radius, often called a "reverse Colles" fracture. The "garden spade" deformity indicates volar angulation and displacement. ### Why CT with 3D Reconstruction? 1. **Intra-articular assessment**: Accurately identifies: - Involvement of the radiocarpal joint - Articular surface comminution - Displacement of intra-articular fragments 2. **Surgical planning**: 3D reconstruction provides: - Precise fracture geometry - Optimal implant selection and positioning - Assessment of associated injuries (scaphoid involvement, ulnar head fracture) 3. **Prognostic value**: Helps predict functional outcomes and need for open reduction and internal fixation (ORIF) ### Comparison of Imaging Modalities | Modality | Utility in Smith Fracture | Limitations | |---|---|---| | **Plain radiography** | Initial diagnosis, displacement assessment | Cannot reliably assess intra-articular involvement | | **CT with 3D reconstruction** | **Gold standard for complex cases** | Higher radiation, cost; reserved for surgical candidates | | **MRI** | Soft tissue injury, ligament assessment | Time-consuming, not ideal for acute fracture characterization | | **Fluoroscopy** | Real-time reduction assessment | Does not provide static anatomic detail; not diagnostic | **High-Yield:** Smith fractures are more common in elderly patients with osteoporosis and carry higher risk of intra-articular involvement compared to Colles fractures. Approximately 50–60% of Smith fractures are intra-articular. **Clinical Pearl:** The volar displacement in Smith fractures can compress the flexor tendons and median nerve. Early assessment of neurovascular status and consideration of urgent reduction are critical. CT helps determine if ORIF is necessary. **Mnemonic:** **SMITH = Volar displacement (flexion injury); COLLES = Dorsal displacement (extension injury)**. When fracture complexity or intra-articular involvement is suspected, CT is the next step after plain films. **Tip:** In this case, the patient has a confirmed Smith fracture on plain radiographs. The question asks for the most appropriate investigation to guide surgical management — this is CT with 3D reconstruction, which provides the anatomic detail necessary for operative planning.