What is the diagnosis?

The patient is presenting with a distal fibular fracture (Weber Class C). 

• Pearl: The Danis-Weber classification is a system to identify fracture stability in lateral malleolar fractures. Weber A injuries are below the syndesmosis (stable), Weber B injuries are at the level of the syndesmosis (variable stability), and Weber C injuries are above the syndesmosis (unstable).

Image 2. Danis-Weber Classification. Illustration courtesy of Frank Gaillard, Radiopaedia.org, rID: 9642

What is the mechanism of injury?

Weber C ankle injuries most commonly occur from dorsiflexion and eversion of the ankle [2]. 

• Pearl: A major risk factor for ankle fractures is osteopenia. Isolated fibular fractures account for the majority of ankle fractures in older women [1]. 

What physical exam findings are expected?

Tenderness and swelling to the ankle joint. Patients with Weber C fractures are likely to have difficulty with ambulation due to inherent instability. 

• Pearl: It is important to examine the entire length of the tibia and fibula in all ankle injuries. Tenderness to the proximal fibula may reveal a Maisonneuve fracture - this injury can lead to ankle instability and early onset arthritis if left untreated [4]. 

Which imaging modalities can be used?

Plain radiographs (AP, lateral and mortise views) are sufficient to diagnose a Weber C fracture. A CT scan may assist in operative planning for complex fractures, or help identify a posterior malleolus fracture. 

• Pearl: Widening of the space between the medial malleolus and talus suggests syndesmotic injury. In Weber B fractures, it is important to obtain stress views to identify subtle syndesmotic injury. If stress views are positive, this indicates potential instability and need for surgical intervention [3]. 

What is the management in the ED?

Weber C fractures are unstable and should be placed in a posterior splint with stirrups. These patients should be made non-weight bearing and referred to orthopedics. 

• Pearl: It is important to distinguish this from stable ankle injuries such as Weber A and some Weber B injuries (depending on the stress films). Stable fractures generally heal well non operatively and do not need routine orthopedic follow up. Rather, those injuries can be managed in a walking boot and made weight bearing as tolerated.  

When do you consult orthopedics?

Significant crush injuries, open fractures or concerns for neurovascular compromise all warrant emergent orthopedic consultation. Otherwise, Weber C fracture patterns should be referred to Orthopedics within 1 week for surgical evaluation and considerations for ORIF.