Scaphoid fracture

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 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. CT and MRI may be indicated if x-ray findings are negative but clinical suspicion is high. All suspected scaphoid fractures should be immobilized in a thumb spica cast. Definitive treatment can be nonoperative (i.e., wrist immobilization) or surgical (e.g., for proximal pole fractures). Complications include nonunion and avascular necrosis.

• Most common carpal bone fracture (50–80%) ^[1]
• Peak incidence: 15–19 years ^[2]

Epidemiological data refers to the US, unless otherwise specified.

• According to the localization of the fracture ^[3]
  • Proximal third (proximal pole): ∼ 10%
  • Middle third (waist): ∼ 70%
  • Distal third (distal pole): ∼ 20%
    • Distal articular surface
    • Distal tubercle

• History of falling onto the outstretched hand; with a hyperextended and radially deviated wrist ^[4]
• Pain when applying pressure to the anatomical snuffbox and scaphoid tubercle (a palpable bony prominence on the inferior lateral edge of the scaphoid bone)
• Minimal reduction in the range of motion (except in dislocated fractures)
• Decreased grip strength
• Painful pinching and grasping
• Pain can be induced through axial compression along the first metacarpal (scaphoid compression test). ^[4]

X-ray is the best initial test; advanced imaging is only indicated in selected cases. ^[5]

X-ray ^[5][6][7]

• Indication: suspected scaphoid fracture
• Views: posteroanterior, lateral, oblique, and scaphoid views
• Findings
  • Radiographic signs of fractures
  • Displacement, bowing, or obliteration of the scaphoid fat pad

Consider advanced imaging if initial x-rays are negative for fractures, as 15–20% of scaphoid fractures are undetectable on the initial x-ray. ^[6]

Advanced imaging ^[5][6]

• Indications
  • Suspected occult fracture ^[8]
  • Suspected associated tendon or ligament injury
  • Preoperative planning for complicated injuries
• Modalities ^[9]
  • Standard modalities: MRI, CT
  • Additional modalities include bone scintigraphy and ultrasound. ^[5][6][7]

Carpal dislocation

Lunate dislocation ^[10][11]

• 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 (e.g., acute carpal tunnel syndrome) ^[12]
• 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; commonly associated with a fractured scaphoid bone (transcaphoid perilunate fracture-dislocation) ^[13]
• Etiology: fall onto a hyperextended wrist, deviated toward the ulna
• Clinical features: usually non-specific (pain in the wrist, swelling, restricted movement); possibly signs of median nerve injury ^[14]
• X-ray: most commonly, metacarpal bones displaced dorsally to the lunate bone in lateral view ^[15]
• Treatment: always surgical ^[16]
  • Closed reduction with cast immobilization
  • Open reduction and internal fixation
  • Scaphoid osteosynthesis

Other fractures

• Distal radius fractures
  • Colles fracture
  • Smith fracture
  • Barton fracture
  • Reverse Barton fracture
  • Hutchinson fracture
  • Die-punch fracture
• Hand fractures
  • Metacarpal fractures (e.g., boxer's fracture)
  • Phalangeal fractures

The differential diagnoses listed here are not exhaustive.

Approach ^[7]

• All suspected scaphoid fractures
  • Provide analgesia for acute fractures.
  • Immobilize in a thumb spica cast or splint.
  • Arrange orthopedic follow-up within one week.
• Confirmed fractures: nonoperative or surgical management (depending on stability)
• Suspected occult fractures: immobilization with x-ray reevaluation after 10–14 days or advanced imaging ^[5]

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

Nonoperative management ^[6]

• Indications: Consider for all stable fractures.
  • Nondisplaced or minimally displaced fractures (< 1 mm)
  • Distal pole fractures
  • Fractures with normal intercarpal alignment
• Technique: immobilization in a short- or long-arm thumb spica cast for at least 6–8 weeks ^[6]

Surgical management ^[6]

• Indications
  • General indications for surgical fracture management, e.g., open fractures, neurovascular compromise
  • Displaced fractures (> 1 mm)
  • Proximal pole fractures ^[6]
  • Carpal instability
  • Radiographic signs of instability, e.g., bone loss
  • Older fractures (> 4 weeks)
• Technique: percutaneous or open reduction and internal fixation

• Avascular necrosis (especially in proximal fractures that disrupt blood flow from branches of the radial artery) of the scaphoid bone in up to 50% of cases ^[17]
• Nonunion (especially in proximal fractures) in approx. 10% ^[18]
• Delayed union of fracture (more common in smokers)
• Instability among carpal joints
• Post-traumatic arthritis

Fractures in the distal third tend to heal better because of the retrograde blood supply reaching the bone from the distal pole.

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