What is the treatment approach for a Salter II fracture of the third and fourth metacarpal heads?

Treatment of Salter II Fractures of the Third and Fourth Metacarpal Heads

Closed reduction and immobilization with a cast or splint is the recommended first-line treatment for Salter-Harris type II fractures of the third and fourth metacarpal heads with minimal displacement (<2mm). 1

Assessment and Classification

• Evaluate fracture displacement using standard radiographs (posteroanterior, lateral, and oblique views)
• Assess for:
  • Amount of displacement (measured in mm)
  • Angulation (degrees)
  • Joint stability
  • Percentage of joint surface involvement
  • Evidence of rotation (may cause finger crossover)

Treatment Algorithm

For Minimally Displaced Fractures (<2mm)

1. Closed reduction under appropriate anesthesia
   • For children: Consider general anesthesia in operating room setting for optimal results 1
   • For older patients: Conscious sedation or regional blocks may be sufficient
2. Immobilization with cast or splint for 30-45 days (duration varies by age) 1
3. Verification radiographs between 7-14 days post-reduction to ensure maintained alignment 1

For Moderately Displaced Fractures (2-4mm)

1. Attempt closed reduction under appropriate anesthesia
2. If reduction achieves <2mm displacement:
   • Immobilize with cast or splint for 30-45 days 1
3. If reduction fails to achieve <2mm displacement:
   • Consider surgical intervention with internal fixation

For Significantly Displaced Fractures (>4mm)

1. Surgical intervention is typically indicated
2. Technique should avoid violating the growth cartilage 1
3. Internal fixation options:
   • Minimally invasive lag screw osteosynthesis 2
   • Transepiphyseal wire fixation 1
4. Post-operative immobilization for approximately 30 days 1

Post-Treatment Care and Rehabilitation

• Early mobilization after stable fixation to prevent stiffness
• Implement directed home exercise program including active motion exercises 3
• Monitor for:
  • Joint stiffness
  • Malunion
  • Growth disturbance
  • Digital hyperextension (common but typically transient) 2

Special Considerations

• Metacarpal neck fractures have varying acceptable angulation across digits (10°, 20°, 30°, and 40° from index to little finger) 4
• Thumb metacarpal base fractures with lateral metaphyseal fragments require special attention and often surgical management 4
• Malunited fractures require surgical correction to avoid long-term functional limitations 1

Recovery Timeline

• Immobilization: 30-45 days depending on age 1
• Return of normal joint mobility: 3-6 months (age-dependent) 1
• Regular follow-up radiographs to ensure proper healing

Potential Complications

• Malunion if reduction is lost or inadequate
• Growth disturbance (though less common in type II fractures compared to types III and IV)
• Joint stiffness
• Chronic pain
• Post-traumatic arthritis

Early appropriate treatment is crucial for preventing complications and ensuring optimal functional outcomes in these pediatric fractures.