What is the likely diagnosis and treatment for a young adult with snuff box tenderness without necrosis, possibly after a recent trauma or fall onto an outstretched hand?

Scaphoid Fracture: Diagnosis and Management

A young adult with anatomical snuff box tenderness following trauma should be treated as having a scaphoid fracture until proven otherwise, requiring immediate immobilization and radiographic evaluation with a minimum 4-view series (PA, lateral, oblique, and dedicated scaphoid view), followed by MRI without IV contrast if initial radiographs are negative but clinical suspicion remains high. 1

Initial Clinical Assessment

The presence of anatomical snuff box tenderness is highly sensitive (90%) for scaphoid fracture, though it has low specificity (40%). 2 Additional clinical findings that increase diagnostic certainty include:

• Scaphoid tubercle tenderness (more specific at 57% than snuff box tenderness alone) 2
• Painful axial thumb compression 3
• Painful ulnar deviation 3
• Swelling of the anatomical snuff box 3

The combination of these findings in a clinical decision rule achieves 97% sensitivity and can reduce unnecessary immobilization by 15% compared to relying on snuff box tenderness alone. 3

Immediate Imaging Protocol

Standard radiographic evaluation must include a minimum 4-view series, not just 2 or 3 views, as the American College of Radiology emphasizes that inadequate imaging leads to missed fractures and subsequent complications including nonunion, avascular necrosis, and post-traumatic arthritis. 1 The required views are:

• Posteroanterior (PA) view
• Lateral view
• 45° semipronated oblique view
• Dedicated scaphoid view 1

Initial radiographs have only 59-79% sensitivity for acute scaphoid fractures, meaning up to 40% of fractures may be radiographically occult initially. 4

Management When Initial Radiographs Are Negative

If clinical suspicion remains high despite negative initial radiographs, proceed immediately to MRI without IV contrast rather than waiting for repeat radiographs. 1 MRI has superior diagnostic performance with:

• 94.2% sensitivity and 97.7% specificity for occult scaphoid fractures 1
• 100% sensitivity and 99% specificity in some studies 4
• Ability to detect bone contusions and concomitant ligament injuries 5

The American College of Radiology notes that while one study showed MRI changed diagnosis in 55% and management in 66% of patients with normal radiographs, another study found no difference in outcomes between MRI and the traditional approach of immobilization with repeat radiographs. 5 However, prioritizing morbidity and mortality, early MRI diagnosis prevents the complications of missed fractures, which include nonunion requiring complex surgical reconstruction and avascular necrosis leading to chronic disability. 1

CT without IV contrast is an alternative if MRI is unavailable, offering high-detail bone imaging with shorter acquisition times and easier use in casted patients. 1

Immobilization Strategy

Immediate immobilization in a short arm cast is mandatory for all patients with snuff box tenderness, even with negative initial radiographs. 6, 7 The traditional approach of casting for 10-14 days followed by repeat radiographs can be replaced by early MRI to avoid unnecessary prolonged immobilization in patients without fractures. 1

Whether thumb immobilization is necessary remains debated, though it remains the standard of care. 6

Critical Pitfalls to Avoid

• Never rely on 2-view radiographs alone—this misses a significant proportion of wrist fractures 1
• Do not dismiss persistent pain after negative initial imaging—worsening symptoms 2 weeks post-injury despite negative radiographs demands MRI to rule out occult fracture, ligamentous injury, or bone contusion 1
• Do not delay immobilization pending imaging results—treat clinically suspected scaphoid fractures immediately to prevent displacement 6, 7
• Pain scores alone are insufficient for diagnosis—while higher pain scores (≥8.5) have 75% sensitivity and 72% specificity, this cannot replace imaging 4

Fracture Location and Referral Indications

All displaced scaphoid fractures and nondisplaced proximal or middle third fractures warrant immediate orthopedic referral due to high nonunion risk from tenuous blood supply. 6, 7 Nondisplaced distal third fractures generally heal well with cast immobilization alone. 6

Operative fixation may be considered even for nondisplaced fractures in athletes requiring early return to sport, as this avoids extended immobilization periods. 7