Treatment of Avulsion Fracture of the Distal Fibula
For avulsion fractures of the distal fibula, functional support with an ankle brace for 4-6 weeks is the preferred initial treatment, with surgical fixation indicated for displaced fragments (>5mm) or when associated with ankle instability. 1
Conservative Management
Initial treatment approach:
Indications for conservative management:
- Minimally displaced avulsion fractures
- Absence of significant ankle instability
- Fragments smaller than 5mm with minimal displacement
Surgical Management
Surgical fixation is indicated in specific scenarios:
- Displacement >5mm in any plane 1
- Presence of ankle instability 2
- Painful nonunion of avulsion fragment 3
- Intra-articular displacement 1
The surgical approach typically involves:
- Screw fixation of the fragment to the fibula 2
- Concomitant repair of lateral ankle ligaments if instability is present 3, 2
Research shows that surgical treatment of symptomatic avulsion fragments (os subfibulare) results in substantial improvement in clinical outcomes with relatively low complication rates 3. A study by Intraoperative findings revealed that both the anterior talofibular ligament and calcaneofibular ligament are typically attached to the avulsion fragment, which is critical because motion between the fragment and fibula may prevent spontaneous healing 2.
Rehabilitation Protocol
Following either conservative or surgical management:
- Progressive range of motion exercises after the immobilization period 1
- Directed home exercise program 1
- Gradual return to activities based on healing and functional recovery 1
- Strengthening exercises once healing is confirmed 1
Special Considerations for Pediatric Patients
Pediatric patients require particular attention as:
- Avulsion fractures are common in children with ankle sprains (62% in one study) 4
- Only 17% of these fractures unite at 8 weeks 4
- Recurrent sprains occur in 44% of children with avulsion fractures vs. 23% without 4
- Nonunion can lead to chronic ankle instability 5
Monitoring and Follow-up
- Radiographic follow-up at 3 weeks and at cessation of immobilization 1
- Special attention to signs of nonunion, which may require later surgical intervention 5
- Monitor for recurrent sprains, especially in pediatric patients 4
Complications to Watch For
- Chronic ankle instability (especially in pediatric patients) 4, 5
- Nonunion of the avulsion fragment 5
- Joint stiffness from excessive immobilization 1
- Peroneal tendon dysfunction if the avulsion involves the superior peroneal retinaculum 6
Early recognition and appropriate management of distal fibular avulsion fractures are essential to prevent chronic ankle instability and ensure optimal functional outcomes.