What is the appropriate treatment for an isolated nondisplaced fracture of the base of a metatarsal?

Treatment for Nondisplaced Fracture of the Base of Metatarsal

Nondisplaced fractures of the metatarsal base should be treated conservatively with protected weight-bearing in a cast shoe or hard-soled shoe for 4-6 weeks, which achieves excellent healing rates and functional outcomes without surgery. 1

Conservative Management Protocol

Immobilization Options

• Use either a controlled ankle motion (CAM)-walker boot or hard-soled shoe for immobilization 2
  • Both methods produce similar clinical and functional outcomes, with VAS pain scores and AOFAS midfoot scores equivalent at 8 and 12 weeks 2
  • CAM-walker boots demonstrate slightly faster radiographic healing (7.2 weeks) compared to hard-soled shoes (8.6 weeks), though time to return to activity is similar (8.3 vs 9.7 weeks) 2
  • Fracture displacement remains minimal with both approaches (mean 1.6-1.9 mm) 2

Weight-Bearing Status

• Protected weight-bearing is appropriate for nondisplaced fractures and those with displacement only in the horizontal plane 1
• Duration of immobilization should be 4-6 weeks 1

Expected Outcomes

• Conservative treatment achieves union in the vast majority of minimally displaced metatarsal base fractures 1
• Mean clinical union time with conservative management is approximately 16 weeks, with radiographic union at 25 weeks 3
• Return to full activity typically occurs around 20-21 weeks with conservative treatment 3

When to Consider Surgical Intervention

Indications for Surgery

While nondisplaced fractures heal well conservatively, surgical fixation should be considered if:

• Displacement exceeds 2 mm or involves more than 30% of the joint surface (particularly for fifth metatarsal avulsion fractures) 1
• The patient is an athlete requiring faster return to activity 3
• Nonunion develops after 3 months of conservative treatment 4

Surgical Outcomes

• Surgical treatment significantly reduces time to clinical union (8.2 weeks), radiographic union (13.5 weeks), and return to activity (12.9 weeks) compared to conservative management 3
• Delayed unions and nonunions occur in 27% of conservatively treated patients but are rare with surgical fixation 3

Critical Pitfalls to Avoid

First Metatarsal Considerations

• First metatarsal fractures require more aggressive treatment than lesser metatarsal fractures due to their critical role in weight-bearing and gait 5
• Even nondisplaced first metatarsal fractures warrant plaster immobilization given the prolonged disability associated with malunion 5
• Malunion in the sagittal plane can result in a nonplantigrade foot with long-term functional impairment 5

Monitoring for Complications

• Assess for associated skeletal injuries that could compromise rehabilitation 6
• Monitor radiographically at regular intervals to detect displacement or delayed healing
• Nonunion risk is higher in zone 2 and 3 fifth metatarsal fractures, though zone 1 fractures can uncommonly develop nonunions 4

Follow-Up Schedule

• Evaluate patients at 4,8,10,12, and 24 weeks or until asymptomatic and able to return to prior activity level 2
• Radiographic assessment should confirm progressive healing and absence of displacement 2