Treatment of Small Avulsion Fracture of the Distal Fibula with Mild Displacement
For a small, mildly displaced avulsion fracture of the distal fibula, treat non-operatively with immobilization, immediate weight-bearing as tolerated, and functional rehabilitation, as these fractures typically heal well without surgery.
Initial Management Approach
The distal fibular avulsion fracture represents a syndesmotic ligament injury pattern, most commonly involving the anterior inferior tibiofibular ligament (AITFL), which occurs in approximately 20% of ankle fractures 1. The treatment decision hinges on the degree of displacement and fragment size:
Non-Operative Treatment (Preferred for Mild Displacement)
Immobilize the ankle using a rigid cast or walking boot for comfort and stability 2
- Apply immobilization for 3-6 weeks depending on pain and clinical healing
- Rigid immobilization is preferred over removable splints for displaced fractures 3
Allow immediate weight-bearing as tolerated with the immobilization device 4
- Studies of similar avulsion fractures demonstrate excellent union rates (98.5%) with immediate ambulatory weight-bearing 4
- This approach minimizes complications from prolonged immobilization while maintaining fracture stability
Implement pain management using a multimodal, opioid-sparing approach 5
When to Consider Operative Treatment
Surgical fixation becomes an option when:
- Fragment size is large enough to potentially interfere with syndesmotic alignment (median fragment size in AITFL avulsions is 16.6 mm, with some exceeding 21 mm) 1
- Significant displacement that prevents adequate reduction with closed treatment 6
- Associated syndesmotic instability requiring fixation 1
For truly "small" and "mildly displaced" fractures as described in your question, these surgical indications are unlikely to be met.
Rehabilitation Protocol
Begin range-of-motion exercises for the ankle, knee, and foot within the first few days once pain is controlled 2
- Early mobilization prevents stiffness in adjacent joints
- Avoid overly aggressive therapy initially to prevent displacement 2
Progress to strengthening exercises once initial pain subsides 2
- Home exercise programs are equivalent to supervised therapy 5
- Focus on preventing ankle stiffness and restoring proprioception
Follow-Up and Monitoring
Obtain serial radiographs at 2 weeks, 6 weeks, and at cessation of immobilization 3
- Monitor for maintenance of alignment
- Confirm progressive healing
Expected time to union averages 3-4 months for similar avulsion fractures 4
Watch for red flags including increasing pain, swelling, loss of function, or neurovascular compromise requiring urgent reassessment 2
Critical Pitfalls to Avoid
Do not over-treat small avulsion fractures surgically - the evidence for similar fracture patterns shows excellent outcomes with conservative management and 100% patient satisfaction 4
Recognize that fragment size matters - while your fracture is described as "small," be aware that AITFL avulsion fragments can be larger than appreciated on plain radiographs 1, so ensure adequate imaging assessment
Avoid prolonged non-weight-bearing - this increases complications without improving outcomes for stable avulsion fractures 4