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

Explanation

## Clinical Presentation of Suspected Scaphoid Fracture **Key Point:** Scaphoid fractures present with a classic triad: (1) fall on outstretched hand (FOOSH), (2) tenderness in the anatomical snuffbox, and (3) pain on axial loading of the thumb (scaphoid compression test). ## Radiographic Findings in Acute Scaphoid Fracture **High-Yield:** Up to 25% of scaphoid fractures are **radiographically occult** on initial plain films, especially non-displaced or minimally displaced fractures. The fracture line may not be visible in the first 10–14 days due to minimal displacement and the complex anatomy of the scaphoid. ## Management Algorithm for Suspected Scaphoid Fracture ```mermaid flowchart TD A[FOOSH + Snuffbox tenderness + Scaphoid compression pain]:::outcome --> B{Plain radiographs show fracture?}:::decision B -->|Yes| C[Classify by location and displacement]:::action B -->|No| D{High clinical suspicion?}:::decision D -->|Yes| E[Immobilize in thumb spica cast]:::action D -->|No| F[Reassure and discharge] E --> G[Repeat radiographs in 10-14 days]:::action G --> H{Fracture now visible?}:::decision H -->|Yes| I[Continue immobilization based on type]:::action H -->|No| J[Consider MRI or CT if persistent symptoms]:::action C --> K[Determine treatment: cast vs surgery]:::action ``` **Clinical Pearl:** In a young, active patient with a clear mechanism of injury and classic clinical signs (snuffbox tenderness + scaphoid compression pain), **clinical diagnosis trumps initial radiographs**. Immobilization should not be delayed while waiting for imaging confirmation. **Mnemonic: FOOSH-SNAP** — **F**all **O**n **O**utstretched **S**hand → **S**nuffbox tenderness, **N**o fracture on X-ray, **A**lways immobilize, **P**icture again in 2 weeks. ## Why MRI or CT Immediately? **Warning:** While MRI is more sensitive (95–100%) for detecting occult fractures, it is **not the first-line next step** in uncomplicated suspected scaphoid fractures. MRI is reserved for: - Persistent symptoms after 2 weeks of immobilization with negative repeat radiographs - Need for urgent diagnosis in high-level athletes - Evaluation of complications (avascular necrosis, nonunion) CT is useful for **characterizing** a known fracture but is not indicated for screening occult fractures. ## Standard of Care The **gold standard approach** for clinically suspected but radiographically occult scaphoid fracture is: 1. Immobilize in a **thumb spica cast** (above-elbow or below-elbow depending on fracture location) 2. **Repeat radiographs in 10–14 days** — by this time, callus formation makes the fracture visible 3. If repeat films are negative and symptoms persist, proceed to MRI or CT [cite:Rockwood & Green's Fractures in Adults 9e Ch 8]