Treatment of Nondisplaced Fourth Metatarsal Base Fracture
Nondisplaced fractures at the base of the fourth metatarsal should be managed conservatively with protected weight-bearing in a cast shoe or walking boot for 4-6 weeks, followed by progressive mobilization and rehabilitation. 1, 2
Initial Management
Conservative treatment is the standard approach for nondisplaced fourth metatarsal base fractures, similar to management principles for other lesser metatarsal fractures. 2
- Immobilize the foot in a walking boot or cast shoe to allow protected weight-bearing from the outset 1, 2
- Duration of immobilization should be 4-6 weeks 2
- Avoid prolonged immobilization beyond what is necessary, as this leads to stiffness and muscle atrophy 1, 3
Diagnostic Confirmation
Before initiating treatment, proper radiographic evaluation is essential:
- Obtain three standard radiographic views (anteroposterior, lateral, and mortise) that include the base of the metatarsal 1, 3
- Weight-bearing radiographs provide important information about fracture stability when possible 1, 3
- Ensure the fracture is truly nondisplaced, as displacement >3-4mm or angulation >10 degrees would require surgical consideration 4
Important Caveat: Fourth Metatarsal Base Fractures Heal Slowly
A critical pitfall is underestimating the healing time for proximal fourth metatarsal injuries. Research demonstrates that fourth metatarsal base fractures behave similarly to the notorious Jones fracture of the fifth metatarsal, with prolonged healing times compared to other lesser metatarsal fractures. 5
- These injuries may remain symptomatic even after 3 months of rest and immobilization 5
- Patients typically return to full activity in 2-8 months, which is considerably longer than standard metatarsal shaft fractures 5
- The adduction mechanism and watershed blood supply at the metaphyseal-diaphyseal junction contribute to delayed healing 5
Optimal Conservative Protocol
Based on evidence from proximal fourth metatarsal injuries, the ideal treatment sequence is:
- Initial phase (3 weeks): Non-weight-bearing or protected weight-bearing in a below-knee cast or boot 5, 6
- Second phase (3+ weeks): Progressive weight-bearing immobilization in a boot 5, 6
- Total immobilization period: 4-6 weeks minimum, but healing may require longer 2, 5
Monitoring and Follow-Up
Regular radiographic assessment is necessary to ensure proper healing and alignment throughout the treatment course. 1, 3
- Obtain follow-up radiographs at 5-6 weeks to assess healing 6
- Continue monitoring until radiographic union is confirmed 1
- Be prepared for prolonged healing times that may extend beyond typical lesser metatarsal fractures 5
Rehabilitation Protocol
Early introduction of physical training after the immobilization period is essential to restore function:
- Begin ankle range-of-motion exercises and strengthening once adequate healing is demonstrated 3
- Progress to muscle strengthening followed by balance training 1, 3
- Gradually increase weight-bearing as tolerated: 25% at week 3,50% at week 4,75% at week 5, and 100% at week 6 (if healing progresses appropriately) 7
When to Consider Surgical Treatment
While your fracture is nondisplaced and should be treated conservatively, surgical intervention would be indicated if:
- Displacement exceeds 3-4mm 4
- Angulation exceeds 10 degrees 4
- The fracture fails to heal after appropriate conservative management 5
- Persistent symptoms continue despite adequate immobilization 5
Common Pitfalls to Avoid
- Failing to include the base of the fourth metatarsal in initial radiographs 1
- Underestimating healing time: Fourth metatarsal base fractures require longer healing than typical metatarsal shaft fractures 5
- Premature return to activity: Patients may remain symptomatic for 3+ months even with appropriate treatment 5
- Excessive immobilization: While adequate immobilization is necessary, prolonged immobilization beyond 6 weeks without progressive mobilization leads to stiffness and muscle atrophy 1, 3