What is the management of Salter-Harris Type 2 fractures of the third and fourth metacarpals?

Management of Salter-Harris Type 2 Fractures of Third and Fourth Metacarpals

Salter-Harris type 2 fractures of the third and fourth metacarpals should be treated with closed reduction and immobilization in a plaster cast for 4-5 weeks, with regular follow-up to ensure proper healing and avoid malunion. 1

Initial Assessment and Diagnosis

• Obtain standard radiographs (posteroanterior, lateral, and oblique views) to confirm the diagnosis and assess fracture displacement 2
• Carefully evaluate for:
  • Displacement (>3mm gap is significant)
  • Angulation (>10 degrees requires intervention)
  • Rotational deformity (even 5 degrees can cause noticeable clinical deformity) 3
  • Joint involvement
  • Associated soft tissue injuries

Treatment Algorithm

For Stable, Minimally Displaced Fractures:

1. Closed reduction under appropriate anesthesia (local or general depending on patient age and cooperation) 1
2. Immobilization with a well-molded plaster cast for 4-5 weeks 1, 4
   • For adolescent athletes, consider a modified functional "glove cast" that allows wrist motion while protecting the fracture 4
3. Follow-up radiographs at 7-14 days to verify maintenance of reduction 1

For Unstable or Significantly Displaced Fractures:

1. Closed reduction with percutaneous pinning or minimally invasive screw fixation 5
   • Avoid violating the growth plate during fixation
2. Post-operative immobilization for 2-4 weeks
3. Early range of motion exercises after immobilization to prevent stiffness 2

Special Considerations

• Rotational deformity requires particular attention as it will not remodel with growth and must be corrected 6, 3
• Adolescent patients (13-16 years) have the highest incidence of metacarpal fractures, often from sports activities 6
• Return to sports can typically begin with modified activity after initial evaluation and immobilization, with full return after radiographic evidence of healing (usually 4 weeks) 4

Complications and Prevention

• Malunion is the most common complication, especially if follow-up is inadequate between 7-14 days post-reduction 1
• Joint stiffness can be prevented with early appropriate range of motion exercises after immobilization 2
• Growth disturbance is rare with proper management of Salter-Harris type 2 fractures but should be monitored

Rehabilitation

• After cast removal, implement a directed home exercise program including active motion exercises 2
• Full recovery of hand function typically occurs within 3-6 months, depending on patient age 1
• Monitor for any signs of malunion, which would require surgical correction if identified late 1

Pitfalls to Avoid

• Failing to check for rotational alignment during reduction (check by flexing fingers - they should point toward the scaphoid)
• Inadequate follow-up between 7-14 days, when loss of reduction is most likely to occur
• Prolonged immobilization leading to joint stiffness
• Confusing pseudoepiphyses with actual fractures in pediatric patients 6

Remember that while most Salter-Harris type 2 fractures of the metacarpals can be successfully treated with closed reduction and immobilization, careful attention to fracture alignment and appropriate follow-up are essential to prevent long-term functional impairment.