What is the management of a closed Salter-Harris type I (physeal fracture) fracture of the first metatarsal bone in a 12-year-old boy?

Management of Closed Salter-Harris Type I Physeal Fracture of First Metatarsal in a 12-Year-Old Boy

The management of a closed Salter-Harris type I physeal fracture of the first metatarsal in a 12-year-old boy should consist of conservative treatment with immobilization in a below-knee cast or walking boot for 4-6 weeks, followed by gradual return to activities.

Initial Assessment and Diagnosis

• Confirm diagnosis with appropriate imaging:
  • Standard radiographs (AP, lateral, and oblique views) to visualize the fracture pattern
  • Consider CT if there's uncertainty about fracture classification or displacement 1
  • MRI may be helpful to exclude other injuries if clinical suspicion remains despite negative radiographs 1

Treatment Algorithm

For Non-Displaced or Minimally Displaced Fractures:

1. Immobilization:

   • Below-knee walking cast or walking boot for 4-6 weeks
   • Non-weight bearing or partial weight bearing for the first 2 weeks, then progress to weight bearing as tolerated
   • Cast should maintain proper foot alignment with slight plantar flexion of the first metatarsal

2. Follow-up:

   • Radiographic verification between 7-14 days after reduction to ensure maintained alignment 2
   • Clinical and radiographic assessment at 4-6 weeks to confirm healing

3. Rehabilitation:

   • After cast removal, begin range of motion exercises
   • Gradual return to activities over 2-4 weeks
   • Full return to sports typically at 8-12 weeks post-injury

For Displaced Fractures:

1. Closed Reduction:

   • Perform under adequate anesthesia (conscious sedation or general anesthesia)
   • Verify reduction with fluoroscopy
   • Immobilize in below-knee cast after reduction 2

2. If Closed Reduction Fails:

   • Consider open reduction with internal fixation
   • Use smooth Kirschner wires placed carefully to avoid growth plate damage
   • Transepiphyseal wires may be used but should avoid violating the growth cartilage 2

Special Considerations

• Growth Plate Protection: Avoid any fixation that crosses the physis if possible to prevent growth disturbance

• Monitoring for Complications:

  • Regular follow-up to detect early signs of growth arrest
  • Watch for malunion, which may require surgical correction if significant 2
  • Monitor for osteonecrosis, though rare in metatarsal fractures 3

• Return to Activities:

  • Emphasize weight-bearing exercise and maintenance of joint range of motion after healing 1
  • Consider protective footwear for return to sports

Pitfalls and Caveats

1. Missed Diagnosis: Salter-Harris type I fractures can be subtle on radiographs and may be mistaken for sprains
2. Inadequate Follow-up: Failure to verify alignment at 7-14 days can lead to malunion 2
3. Premature Return to Activities: Can lead to refracture or displacement
4. Growth Disturbance: Even properly treated physeal fractures can lead to growth arrest; parents should be informed of this possibility
5. Surgical Risks: If surgery is needed, it should be performed by a surgeon with expertise in pediatric foot injuries 1

Salter-Harris type I fractures generally have good outcomes with proper management, but careful attention to alignment and appropriate immobilization is essential to prevent long-term complications that could affect foot function and development.