Danis-Weber Classification of Ankle Fractures

Ankle fractures are among the most common lower limb injuries encountered in orthopedic and physiotherapy settings. The Danis-Weber classification, commonly referred to as the Weber classification, categorizes lateral malleolar fractures by assessing the fracture’s anatomical position in relation to the tibiofibular syndesmosis - the ligamentous structure that connects the distal tibia and fibula.

This classification system not only helps clinicians in diagnosis but also in predicting the stability of the fracture and guiding treatment decisions.

 

What is the Tibiofibular Syndesmosis?

The syndesmosis is a fibrous joint where the distal tibia and fibula are held together by strong ligaments. It plays a crucial role in ankle stability. Injury or widening of this joint can lead to instability and poor functional outcomes if not treated properly.

The Danis-Weber Classification

The classification is divided into three types - Type A, B, and C, based on the location of the fibular fracture in relation to the syndesmosis:

 

Weber Type A

• Fracture Location: Distal to the level of the syndesmosis
• Typical Pattern: Transverse or short oblique fracture of the lateral malleolus
• Stability: Generally stable
• Syndesmosis: Intact
• Deltoid Ligament: Intact
• Medial Malleolus: May have an associated oblique or vertical fracture
• Management:

1. Most cases can be managed conservatively
2. ORIF (Open Reduction and Internal Fixation) may be required if the medial malleolus is also fractured or if the ankle mortise is compromised

Clinical Insight - these are often caused by inversion injuries and typically have a good prognosis if treated appropriately.

 

Weber Type B

• Fracture Location: At the level of the syndesmosis (tibial plafond)
• Typical Pattern: Oblique fracture of the fibula that extends upward from the level of the syndesmosis
• Stability: Variable
• Syndesmosis: Intact or partially torn, but without widening
• Deltoid Ligament: May be torn
• Medial Malleolus: May also be fractured
• Management:

1. Depends on the integrity of the syndesmosis and medial structures
2. Surgical fixation is considered if instability or widening of the joint is suspected

Clinical Insight - careful assessment with stress radiographs or MRI may be needed to assess the extent of ligament damage.

 

Weber Type C

• Fracture Location: Proximal to (above) the level of the syndesmosis
• Typical Pattern: High fibular fracture often with associated syndesmotic injury
• Stability: Unstable
• Syndesmosis: Disrupted, often with widening of the distal tibiofibular joint
• Deltoid Ligament: Often injured
• Medial Malleolus: Frequently fractured
• Management:

1. Requires ORIF to stabilize both the fibular fracture and the syndesmosis
2. Syndesmotic screws or fixation devices may be used

Clinical Insight - these injuries are frequently associated with high-energy trauma or external rotation injuries, and have a higher risk of complications if not managed surgically.

 

Why the Danis-Weber Classification Matters?

This classification is particularly useful because:

• It correlates well with injury mechanism
• Helps predict fracture stability
• Provides a clear guide for treatment decisions
• Is easy to apply using standard radiographs (X-rays)