What is the recommended treatment for a 9-year-old female with a slight widening of the growth plate at the base of the fifth metatarsal and a possible subtle epiphyseal avulsion?

Management of Fifth Metatarsal Growth Plate Injury in a 9-Year-Old Female

Non-operative treatment with a CAM walker boot and weight-bearing as tolerated is the recommended approach for this 9-year-old female with slight widening of the growth plate at the base of the fifth metatarsal and possible subtle epiphyseal avulsion. 1

Initial Assessment and Diagnosis

The radiographic finding of "slight widening of the growth plate at the base of the fifth metatarsal" with a possible "subtle epiphyseal avulsion" represents a Zone 1 fifth metatarsal injury involving the growth plate (physis). This type of injury is particularly important in pediatric patients due to the presence of open growth plates and potential for growth disturbance.

Key considerations in this case:

• 9-year-old female with open growth plates
• Minimal displacement (widening of growth plate)
• Possible subtle epiphyseal avulsion

Treatment Recommendations

Primary Treatment

1. CAM walker boot immobilization for 6-8 weeks 1, 2

   • Research shows faster bone healing with CAM walker boot (7.2 weeks) compared to hard-soled shoes (8.6 weeks) 2
   • Weight-bearing as tolerated is permitted within the boot

2. Activity modification

   • Limit high-impact activities during healing period
   • Gradual return to activities based on clinical and radiographic healing

3. Pain management

   • Age-appropriate analgesics as needed for pain control

Follow-up Protocol

• Clinical and radiographic assessment at 2,6, and 12 weeks 1
• Monitor for:
  • Proper healing of the growth plate
  • Development of growth arrest lines (which may appear as transverse lines in the metaphysis) 3
  • Any signs of growth disturbance

Expected Timeline

• Bone healing typically occurs within 7-8 weeks 2
• Return to prior activity levels typically occurs around 8-10 weeks for conservatively treated fractures 1

Special Considerations for Pediatric Growth Plate Injuries

1. Growth plate protection is paramount

   • Avoid treatments that could potentially damage the growth plate further
   • Hormonal agents should not be used in patients who have not achieved full sexual maturation and adult stature 4

2. Monitoring for growth disturbance

   • Regular follow-up is essential to detect any growth abnormalities early
   • Intra-epiphyseal growth arrest silhouettes may develop after physiological stress or trauma to the growth plate 3

3. Inflammatory response management

   • A limited physiological inflammatory response locally favors tissue repair, but uncontrolled inflammation can lead to tissue destruction 5
   • Age-appropriate anti-inflammatory medications may be considered if significant inflammation is present

When to Consider Alternative Treatment

1. Indications for surgical intervention:

   • Displacement >30% of the cubometatarsal joint 1
   • Failure of conservative management
   • Progressive displacement during follow-up

2. When to consider MRI:

   • If radiographs are negative but clinical suspicion remains high 1, 4
   • To better evaluate the extent of growth plate involvement

Pitfalls to Avoid

1. Avoid conventional footwear without proper offloading

   • Standard therapeutic footwear without proper offloading devices may delay healing 1

2. Avoid premature return to high-impact activities

   • Even after clinical healing, the growth plate remains vulnerable

3. Don't ignore follow-up radiographs

   • Regular radiographic assessment is crucial to ensure proper healing and to detect any growth disturbance early

This treatment approach prioritizes growth plate protection and optimal bone healing while minimizing the risk of long-term growth disturbance, which is the primary concern in pediatric metatarsal injuries involving the growth plate.