How is a Smith fracture immobilized?

Smith Fracture Immobilization

Smith fractures should be immobilized with a cast in a position of wrist flexion and forearm supination to counteract the volar displacement of the distal fragment.

Understanding Smith Fractures

Smith fractures (also known as reverse Colles' fractures) are characterized by volar displacement of the distal radius fragment. This is in contrast to the more common Colles' fracture which has dorsal displacement. Proper immobilization is critical to maintain reduction and promote healing.

Immobilization Approach

Conservative Management

For stable, non-displaced or minimally displaced Smith fractures (Type I and some Type III):

• Initial immobilization:

  • Apply a well-padded cast with the wrist in slight flexion (15-20°)
  • Maintain forearm in supination
  • Extend the cast from below the elbow to the metacarpophalangeal joints
  • Ensure the thumb is free to move

• Duration of immobilization:

  • Typically 3-4 weeks is sufficient for most Smith fractures 1
  • Shorter immobilization periods (1-3 weeks) have shown better short-term outcomes compared to 6 weeks of immobilization 2

• Follow-up:

  • Radiographic evaluation at 10-14 days to ensure maintained reduction 3
  • If displacement occurs during follow-up, surgical intervention may be necessary

Surgical Management

For unstable Smith fractures (Type II and unstable Type III):

• Indications for surgical intervention:

  • Significant displacement or angulation
  • Palmar displacement of the distal fragment
  • Interfragmentary gap >3 mm
  • Failed closed reduction
  • Unstable reduction 3, 1

• Post-surgical immobilization:

  • After volar locking plate fixation, evidence suggests that immediate mobilization may be superior to splinting 4
  • If immobilization is used post-operatively, shorter periods (1-3 weeks) show better outcomes than longer periods 2

Monitoring and Complications

• Monitor for signs of poor perfusion:

  • Blue, purple, or pale extremities indicate poor perfusion requiring immediate medical attention 5
  • Check for excessive swelling that may compromise circulation

• Common complications to watch for:

  • Joint stiffness (most common)
  • Chronic pain
  • Post-traumatic arthritis 3

• Pain management:

  • NSAIDs are recommended for pain and inflammation control
  • Ice application can provide symptomatic relief 3

Rehabilitation

• After immobilization period:
  • Begin progressive range of motion exercises
  • Full recovery typically expected within 6-8 weeks 3
  • Directed home exercise programs including active finger motion exercises are recommended to prevent stiffness

Clinical Pearls

• Smith fractures are less common than Colles' fractures but require different immobilization positioning
• The key to successful conservative management is maintaining the wrist in flexion and supination
• Unstable fractures (particularly Type II) typically require surgical intervention with volar buttress plating 1
• Avoid the common pitfall of immobilizing Smith fractures in extension (which is appropriate for Colles' fractures but will worsen Smith fracture alignment)
• For pediatric torus fractures of the distal forearm, encircling casts may provide better pain control than volar slabs 6