Can you weightbear in a Controlled Ankle Movement (CAM) boot with a mildly displaced oblique fracture of the distal fibula?

Weight-Bearing in CAM Boot for Mildly Displaced Oblique Distal Fibula Fracture

Protected weight-bearing as tolerated with a CAM boot is recommended for patients with a mildly displaced oblique fracture of the distal fibula, with progression to full weight-bearing as pain allows. 1

Assessment of Fracture Stability

The key factor in determining weight-bearing status is fracture stability:

• Medial Clear Space (MCS) Assessment:

  • If MCS is less than 4mm on initial non-weight-bearing radiographs, immediate weight-bearing in a CAM boot is appropriate 2
  • Follow-up weight-bearing radiographs at 1 week are crucial to confirm continued stability 2

• Radiographic Views:

  • Standing (weight-bearing) radiographs are preferred when possible to detect dynamic abnormalities 3
  • Include anteroposterior (AP), medial oblique, and lateral projections 3

Weight-Bearing Protocol

1. Initial Phase (0-2 weeks):

   • Protected weight-bearing as tolerated in CAM boot with assistive device (crutches/walker) 1
   • Follow-up at 1-2 weeks with weight-bearing radiographs to ensure maintained alignment

2. Progressive Phase (2-6 weeks):

   • If alignment maintained, progress to full weight-bearing in CAM boot as pain allows
   • Total immobilization period typically 4-6 weeks 1

3. Transition Phase (after 6 weeks):

   • Gradual transition to regular footwear as fracture healing progresses
   • Rehabilitation exercises to restore strength and range of motion

Evidence Supporting Early Weight-Bearing

Recent research demonstrates several advantages to early weight-bearing:

• Patients with early weight-bearing protocols reached full weight-bearing at 7±3 weeks compared to 13.5±9.4 weeks in non-weight-bearing groups 4
• Early weight-bearing showed no disadvantages regarding pain intensity or functional outcomes 4
• Modern fixation techniques with anatomically contoured locking plates have shown 100% healing rates with immediate full weight-bearing protocols 5

Special Considerations

• Diabetes: Patients with diabetes may require more aggressive immobilization with a non-removable knee-high device to ensure compliance and prevent complications 1

• Elderly Patients: May benefit from earlier mobilization to prevent deconditioning 1

• Athletes: May require more structured rehabilitation protocols for return to sport 1

Monitoring and Follow-Up

• Clinical and radiographic follow-up at 2 weeks and 4-6 weeks to ensure maintained alignment 1
• Monitor for complications such as:
  • Delayed union or non-union
  • Post-traumatic arthritis
  • Persistent pain or instability

Warning Signs to Reduce Weight-Bearing

• Increasing pain with weight-bearing
• Widening of the MCS on follow-up radiographs (>4mm)
• Progressive displacement of the fracture
• Significant swelling or skin compromise

Early mobilization and weight-bearing as tolerated in a CAM boot for stable distal fibula fractures promotes better functional outcomes without compromising fracture healing when properly monitored with appropriate follow-up imaging.