What is the treatment for a fracture at the base of the first metatarsal?

Treatment of First Metatarsal Base Fractures

For non-displaced first metatarsal base fractures, immobilize with a short leg walking cast or boot for 4-6 weeks with initial non-weight-bearing followed by progressive weight-bearing as tolerated; displaced fractures require rigid internal fixation using AO techniques to prevent malunion and restore normal gait mechanics. 1

Initial Assessment and Imaging

• Obtain proper radiographic evaluation with three standard views (anteroposterior, lateral, and mortise) to accurately diagnose the fracture and assess displacement 2
• Weight-bearing radiographs provide critical information about fracture stability and alignment 2
• Assess for obvious deformity, swelling, severe pain with movement, and ability to bear weight 2

Treatment Algorithm Based on Fracture Pattern

Non-Displaced Fractures

• Immobilize with a short leg walking cast or boot for 4-6 weeks 3
• Initial period of non-weight-bearing (typically 1-2 weeks) followed by progressive weight-bearing as tolerated 2
• Regular radiographic assessment every 2-3 weeks to ensure proper healing and alignment 2

The literature shows considerable variation in immobilization duration, but the consensus supports 4-6 weeks of casting for closed, non-displaced fractures 1. First metatarsal fractures require aggressive treatment because any injury to the first ray drastically alters normal gait and weight-bearing patterns 1.

Displaced or Comminuted Fractures

• Rigid internal fixation using AO techniques is the preferred surgical approach 1
• For fractures with severe soft tissue damage, consider Ilizarov mini-external fixator to prevent further soft tissue compromise 4
• Weight-bearing typically permitted at 7 weeks post-operatively with external fixation 4

Distal Lateral Chip Fractures of First Metatarsal Head

• Early fragment excision allows faster return to activity (6 weeks earlier) compared to immobilization alone 5
• Alternative treatment includes percutaneous pinning or weight-bearing cast, though recovery is slower 5

Critical Management Principles

The first metatarsal's thick size and shape make fractures rare, but when they occur, aggressive treatment is essential to prevent prolonged disability 1. The most significant long-term complication is malunion in the sagittal plane, resulting in a non-plantigrade foot that severely impairs function 1.

Special Considerations

• For patients with diabetes and neuropathy, implement strict offloading protocols to prevent complications during healing 2
• If the foot appears blue, purple, or pale, seek immediate medical attention as this indicates vascular compromise 2
• Avoid prolonged immobilization beyond necessary healing time to prevent stiffness and muscle atrophy 2

Rehabilitation Protocol

• Initiate early physical training and muscle strengthening once initial healing is confirmed 2
• Progress to long-term balance training to restore normal gait mechanics 2
• Transition from cast/boot to rigid-sole shoe as healing progresses 3

Common Pitfalls to Avoid

• Underestimating the importance of sagittal plane alignment - malunion in this plane is the primary cause of long-term disability 1
• Inadequate initial immobilization leading to displacement of initially non-displaced fractures 1
• Premature weight-bearing before adequate fracture stability is achieved 3
• Failing to recognize associated soft tissue damage that may require modified surgical approach 4