What are the treatment options for a minimally displaced oblique distal fibula fracture with chronic widening of the medial space?

Treatment of Minimally Displaced Oblique Distal Fibula Fracture with Medial Space Widening

The critical decision hinges on whether the medial clear space widening represents acute deltoid ligament injury (indicating instability requiring surgery) versus chronic widening (allowing conservative management of the minimally displaced fibular fracture). 1

Initial Assessment and Stability Determination

Obtain weight-bearing radiographs to definitively assess ankle mortise stability, as this is the most important criterion in treatment of malleolar fractures. 1 A medial clear space of <4 mm confirms stability and supports conservative treatment. 1

Key Clinical Indicators of Instability Requiring Surgery:

• Medial tenderness, bruising, or swelling (suggests acute deltoid injury) 1
• Fibular fracture above the syndesmosis 1
• Bi- or trimalleolar fractures 1
• High-energy mechanism 1
• Medial clear space ≥4 mm on weight-bearing views 1

If the medial space widening is truly chronic (no acute medial tenderness/swelling, stable on weight-bearing films with <4 mm medial clear space), treat the minimally displaced fibular fracture conservatively. 1

Conservative Treatment Protocol (for Stable Fractures)

Removable splinting is the appropriate treatment for minimally displaced fractures. 2, 3

Immobilization Details:

• Duration: 3-4 weeks of immobilization 2
• Active finger and toe motion exercises must be performed from diagnosis to prevent stiffness, which is one of the most functionally disabling complications 2, 3
• Partial weight-bearing (15-20 kg) in ankle-foot orthosis for 6 weeks 4

Follow-up Protocol:

• Radiographic evaluation at approximately 3 weeks post-immobilization to assess healing 2, 3
• Repeat imaging at time of immobilization removal to confirm adequate healing 2, 3
• Re-evaluate immediately if unremitting pain develops during follow-up 1

Surgical Treatment (for Unstable Fractures)

If acute medial instability is confirmed (medial clear space ≥4 mm on weight-bearing films, acute medial tenderness/swelling), surgical fixation is required. 1

Surgical Options:

• Minimally invasive intramedullary fibular nailing provides excellent functional outcomes with significantly lower wound complication rates compared to traditional plating (union rates 97.4-100%, mean AOFAS scores 88.4) 4, 5
• Traditional open reduction internal fixation with lateral plating remains the gold standard but carries higher wound complication risk 5
• Minimally invasive plate osteosynthesis is an alternative with comparable outcomes 5

Syndesmotic Considerations:

• If residual syndesmotic instability persists after fibular fixation, syndesmotic screws should be inserted 4
• Gravity stress views are more reliable than manual stress views for detecting deltoid ligament disruption in supination-external rotation injuries 1

Critical Pitfalls to Avoid

Do not manipulate the ankle prior to obtaining radiographs unless there is neurovascular deficit or critical skin injury, as this may complicate subsequent management. 1

Immobilization-related complications occur in approximately 14.7% of cases (skin irritation, muscle atrophy), emphasizing the importance of active digit motion exercises throughout treatment. 2

Beware of misdiagnosing chronic medial space widening as acute instability—the presence or absence of acute medial soft tissue signs (tenderness, swelling, bruising) combined with weight-bearing radiographs distinguishes these scenarios. 1