A 28-year-old male carpenter from Delhi presents to the emergency department with pain and swelling over the radial aspect of his left wrist following a fall on an outstretched hand (FOOSH) 3 days ago. On examination, there is tenderness in the anatomical snuffbox and pain on axial loading of the thumb. Plain radiographs of the wrist (PA, lateral, and scaphoid views) appear normal. What is the most appropriate next step in management?

Explanation

## Clinical Presentation and Diagnosis **Key Point:** Scaphoid fractures are frequently occult on initial plain radiographs, especially non-displaced fractures. Clinical suspicion based on mechanism (FOOSH) and anatomical snuffbox tenderness is sufficient to warrant treatment even with normal initial imaging. **High-Yield:** The classic triad for suspected scaphoid fracture is: 1. Mechanism: FOOSH injury 2. Tenderness in anatomical snuffbox 3. Pain on axial loading of thumb (longitudinal compression) ## Management Algorithm for Suspected Scaphoid Fracture ```mermaid flowchart TD A[FOOSH + Snuffbox tenderness]:::outcome --> B{Plain radiographs normal?}:::decision B -->|Yes, high clinical suspicion| C[Immobilize in thumb spica cast]:::action C --> D[Repeat radiographs in 10-14 days]:::action D --> E{Fracture visible?}:::decision E -->|Yes| F[Continue immobilization 10-12 weeks]:::action E -->|No, but pain persists| G[MRI or CT for confirmation]:::action B -->|No, low suspicion| H[Conservative management, follow-up]:::action ``` ## Rationale for Immobilization First **Clinical Pearl:** Approximately 15-20% of scaphoid fractures are not visible on initial radiographs due to non-displacement or subtle fracture lines. Immobilization prevents displacement and allows healing to begin; repeat imaging in 10-14 days typically shows callus formation and confirms the fracture. **Key Point:** Early immobilization in a thumb spica cast (extending from below the elbow to the interphalangeal joint of the thumb) is the standard of care for clinically suspected scaphoid fractures, regardless of initial radiographic findings. ## Why Not MRI or CT Immediately? - **Cost and availability:** MRI is more expensive and not routinely available in emergency settings. - **Unnecessary delay:** Immobilization should begin immediately; advanced imaging is reserved for cases where plain radiographs remain negative after 10-14 days and clinical suspicion persists. - **Ligamentous injury:** While MRI can detect associated injuries, the primary concern is the fracture itself, which will declare itself on repeat radiographs. **Mnemonic:** **CAST FIRST** — Clinically suspected scaphoid fractures should be Assessed with imaging, but if normal, Start immobilization and reimage in 10-14 days; only then consider advanced imaging if still negative. [cite:Rockwood & Green's Fractures in Adults Ch 7]