• Clinical science

Scaphoid fracture

Summary

The scaphoid bone is the most commonly fractured carpal bone. Fractures are most often localized in the middle third of the scaphoid bone. Generally, scaphoid bone fractures result from indirect trauma when an individual falls onto the outstretched hand with a hyperextended and radially deviated wrist. Pain when applying pressure to the anatomical snuffbox is highly suggestive of a scaphoid bone fracture. X-ray is the initial test of choice for diagnosis. Computer tomography and magnetic resonance imaging may be indicated, if x-ray findings are negative but clinical suspicion is high. Treatment can be conservative (e.g, wrist immobilization) or in certain cases surgical (e.g., proximal pole fracture). Complications include nonunion and avascular necrosis.

Epidemiology

  • Most common carpal bone fracture (60–70%)
  • Peak incidence: 20–24 years

References:[1]

Epidemiological data refers to the US, unless otherwise specified.

Clinical features

  • History of falling onto the outstretched hand; with a hyperextended and radially deviated wrist.
  • Pain when applying pressure to the anatomical snuffbox and scaphoid tubercle
  • Minimal reduction in the range of motion (except in dislocated fractures)
  • Decreased grip strength
  • Painful pinching and grasping

When pain occurs in the anatomical snuffbox after trauma, the injury should be treated as a scaphoid fracture until proven otherwise!

References: [1]

Diagnostics

  • Imaging
  • Best initial test: X-ray of the wrist in a posteroanterior, lateral, 45° oblique, and possibly scaphoid view
  • If initial x-ray is negative, one of the following:
    • If the patient is not willing to immobilize the wrist: MRI of the wrist
    • If the patient is willing to immobilize the wrist: cast the wrist and repeat an x-ray in 10–14 days
      • If repeat x-ray is normal but continued clinical suspicion of scaphoid fracture: MRI wrist

Scaphoid fractures are often overlooked on the initial x-ray!References:[1][2]

Differential diagnoses

Lunate dislocation

  • Definition: disruption of perilunate ligaments and radiocarpal ligament with displacement of the lunate bone (usually volarly) while the rest of the carpal bones remain in a normal anatomic position
  • Etiology: high-energy trauma with dorsal extension and ulnar deviation of the wrist
  • Clinical features: : wrist swelling, pain, and signs of median nerve injury (25% of patients)
  • X-ray: the lateral radiograph shows a loss of colinearity of radius, lunate, and capitate
  • Treatment: emergent closed reduction and immobilization followed by open reduction and internal fixation

Transscaphoid perilunate dislocation

  • Definition: dorsal dislocation of the wrist around the fixated, unmoved lunate bone with a fractured scaphoid bone
  • Etiology: fall onto a hyperextended wrist, deviated toward the ulna
  • Clinical features: no pain while applying pressure to the snuffbox, pain in the wrist, possibly signs of median nerve injury
  • X-ray: most commonly, metacarpal bones displaced dorsally to the lunate bone in lateral view
  • Treatment: always surgical (reposition and decompression of the median nerve; osteosynthesis)

References:[3][4][5]

The differential diagnoses listed here are not exhaustive.

Treatment

  • Pain management: over-the-counter analgesics
  • Displaced scaphoid fractures (< 1 mm): wrist immobilization via thumb spica cast for 4–6 weeks
  • Surgical treatment: usually internal fixation

References:[1][6][2]

Complications

Fractures in the distal third tend to heal better because of the retrograde blood supply reaching the bone from the distal pole!References:[1][2]

We list the most important complications. The selection is not exhaustive.