What are the diagnostic steps and management options for a suspected scaphoid fracture?

Diagnosis of Scaphoid Fracture

Initial radiographs with dedicated scaphoid views should be the first diagnostic step for suspected scaphoid fractures, followed by MRI without contrast if clinical suspicion remains high despite negative X-rays. 1, 2

Initial Evaluation

Clinical Assessment

• Look for:
  • Anatomic snuffbox tenderness (most sensitive finding)
  • Pain with axial compression of the thumb
  • Scaphoid tubercle tenderness
  • Pain with wrist range of motion, especially extension

Initial Imaging

1. Standard 3-view radiographs of the wrist:

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

2. Additional dedicated scaphoid view - critical for visualizing occult fractures 2

   • Consider additional views such as carpal tunnel or semisupinated oblique projection for better visualization 1

CAUTION: Initial radiographs miss 20-30% of scaphoid fractures 2

Advanced Imaging Algorithm

When initial X-rays are negative but clinical suspicion remains high:

1. MRI without contrast (preferred first advanced imaging)

   • Highest sensitivity for detecting occult fractures
   • Can detect bone marrow edema and fracture lines not visible on X-ray
   • Can be performed as early as 2-3 days after injury 3
   • Provides information about associated soft tissue injuries 1
   • Particularly valuable in osteoporotic patients 2

2. CT without contrast (if MRI is contraindicated or unavailable)

   • Excellent visualization of cortical and trabecular bone detail
   • High specificity (100%) but lower sensitivity (94.4%) compared to MRI 2
   • Indispensable for fracture classification and treatment planning 4
   • May show false negatives in osteoporotic patients 2

3. Bone scan (if MRI and CT are contraindicated)

   • High sensitivity but lower specificity
   • Typically positive 1-2 weeks after injury 2
   • Single-photon emission computed tomography (SPECT)/CT increases specificity 1, 2

4. Ultrasound - not recommended as primary diagnostic tool

   • Limited utility with insufficient evidence for routine use
   • Low sensitivity (47%) and specificity (61%) 1

Fracture Classification and Management

Classification (Herbert and Krimmer) 4

• Type A: Stable fractures
• Type B: Unstable fractures

Management

1. Initial Management:

   • Immobilize the wrist in all suspected cases while awaiting definitive diagnosis 2, 5

2. For confirmed non-displaced/stable fractures:

   • Cast immobilization is appropriate
   • Short-arm thumb spica cast for 6 weeks 5
   • CT assessment at 6 weeks to evaluate healing (≥50% trabecular bridging indicates sufficient healing) 5

3. For displaced/unstable fractures:

   • Surgical fixation with double-threaded headless screws is strongly recommended 4
   • Operative technique depends on fracture morphology

Diagnostic Pitfalls to Avoid

1. Relying solely on initial X-rays to rule out fracture
2. Delaying advanced imaging when clinical suspicion is high
3. Failing to immobilize the wrist while awaiting definitive diagnosis
4. Using ultrasound as the primary diagnostic tool
5. Overlooking alternative diagnoses when scaphoid fracture is ruled out 2

Follow-up Evaluation

• CT scan at 6 weeks to assess union 5
• Continue immobilization if healing is incomplete
• Consider surgical intervention for delayed union

Early diagnosis and appropriate management are critical to prevent complications such as nonunion, avascular necrosis, and osteoarthritis that can lead to painful impairment of wrist function 4, 3.