What is the step-by-step procedure for treating a distal radius fracture in a 10-year-old patient using 1 K-wire (Kirschner wire) with elbow flexion and forearm in prone position casting?

Step-by-Step Procedure for K-Wire Fixation of Distal Radius Fracture in a 10-Year-Old Child

Overview

The recommended procedure for treating a distal radius fracture in a 10-year-old using a single K-wire with elbow flexion and forearm pronation casting involves closed reduction followed by percutaneous pinning and appropriate immobilization. This technique is suitable for unstable extra-articular fractures that require additional fixation beyond casting alone 1.

Pre-Procedure Preparation

1. Imaging Assessment:

   • Obtain standard radiographs (anteroposterior, lateral, and mortise views) to assess fracture pattern and displacement 1
   • Confirm fracture is suitable for K-wire fixation (typically extra-articular with moderate displacement)

2. Anesthesia:

   • General anesthesia or regional block (axillary or Bier block) is required for pediatric patients
   • Ensure adequate analgesia and muscle relaxation

Step-by-Step Procedure

1. Patient Positioning

• Position patient supine on operating table
• Place arm on radiolucent arm table
• Prepare and drape the extremity using sterile technique
• C-arm fluoroscopy should be available and positioned for AP and lateral views

2. Fracture Reduction

• Apply longitudinal traction to disarm the fracture
• Correct dorsal angulation by applying pressure on the distal fragment
• Restore radial length and correct any radial deviation
• Verify reduction under fluoroscopy in both AP and lateral views

3. K-Wire Insertion

• Identify the entry point at the radial styloid process, being careful to avoid the superficial branch of the radial nerve 2
• Make a small stab incision at the entry point
• Insert a single 1.6mm K-wire through the radial styloid process 3
• Direct the K-wire from distal to proximal, crossing the fracture site
• Ensure the wire engages the opposite cortex for better stability
• Verify wire position using fluoroscopy in both AP and lateral views

4. Wire Management

• Cut the K-wire leaving approximately 1cm protruding from the skin for later removal 4
• Bend the exposed end to prevent migration
• Cover the pin site with sterile dressing

5. Cast Application

• Position the elbow in flexion (typically 90 degrees)
• Place the forearm in pronation (prone position)
• Apply well-padded below-elbow cast extending to just below the elbow flexion crease
• Mold the cast appropriately to maintain the reduction
• Ensure the cast is not too tight by checking distal circulation, sensation, and movement

Post-Procedure Management

1. Immediate Post-Procedure Care:

   • Elevate the extremity to minimize swelling
   • Monitor neurovascular status (circulation, sensation, movement of fingers)
   • Provide appropriate analgesia

2. Follow-up Protocol:

   • First follow-up at 1 week to check pin site and cast integrity
   • Radiographic follow-up at 3-4 weeks to assess healing 1
   • K-wire removal typically at 4 weeks 4
   • Continue cast immobilization for additional 2 weeks after wire removal 4
   • Total immobilization period: approximately 6 weeks

3. Rehabilitation:

   • Early finger motion is essential to prevent edema and stiffness 1
   • After cast removal, begin active and passive range of motion exercises
   • Home exercise program focusing on wrist and forearm mobility 1

Potential Complications and Prevention

• Pin Site Infection:

  • Monitor for redness, drainage, or increased pain
  • Pin site care with regular cleaning
  • Note: Prophylactic antibiotics may not be necessary as infection rates are low (2%) with proper technique 4

• Nerve Injury:

  • Careful K-wire placement to avoid the superficial branch of the radial nerve
  • Use the "blind region" approach when inserting through the radial styloid 2

• Loss of Reduction:

  • Ensure proper K-wire placement and cast molding
  • Regular radiographic follow-up to detect early displacement

• Joint Stiffness:

  • Encourage early finger motion during immobilization period
  • Implement appropriate rehabilitation after cast removal 1

Special Considerations for Pediatric Patients

• Children have greater remodeling potential, allowing for acceptance of some residual deformity
• Growth plate (physis) must be respected during K-wire placement to avoid growth disturbances
• Children typically heal faster than adults, but require close monitoring to ensure proper alignment is maintained
• Consider shorter immobilization periods in younger children to prevent excessive stiffness

This procedure offers a minimally invasive approach with good outcomes for pediatric distal radius fractures when properly executed with appropriate follow-up care.