Ankle Fractures

Ankle fractures are fractures that can involve the distal tibia, distal fibula, talus, and calcaneus.¹

There is a separate article entitled Ankle Injuries that discusses history, examination, investigation (including information on the Ottawa rules) and differential diagnosis of ankle injuries.

There are 2 joints that allow movement of the ankle:

• The true ankle joint (tibiotalar joint) - articulation is between the lower end of the tibia, the two malleoli and the body of the talus. This joint allows dorsiflexion and plantar flexion of the ankle.
• The subtalar joint - articulation is between the talus and calcaneus. This joint allows inversion and eversion of the ankle.

The distal tibia has a prominent medial malleolus and a less prominent posterior malleolus. The distal fibula is known as the lateral malleolus. The joint capsule and the surrounding ligaments stabilise the ankle. The distal fibula is joined to the distal tibia by the anterior and posterior inferior tibiofibular ligaments, an inferior transverse ligament, and a syndesmosis ligament.² The anterior and posterior talofibular ligaments join the fibula to the talus. The talus is joined to the calcaneus by the calcaneofibular ligament.² The deltoid ligament joins the medial malleolus to the talus, calcaneus, and navicular bones.²

History and examination of ankle injuries is discussed in detail in the Ankle Injuries article. Please refer to this article. However, some key points for suspected ankle fractures are detailed below.

Principles of care for ankle fractures¹

When assessing ankle fractures, consider:

• What was the mechanism of injury (inversion, eversion, plantar flexion, dorsiflexion)? This can help to determine the nature and severity of the injury.
• Are there associated injuries (ligamentous, capsular, vascular)?
• Does the ankle need immobilising?
• Is specialist orthopaedic referral needed?

Examination

• Ankle fractures and ankle sprains can present in a similar way.
• Features that may suggest a fracture include: obvious deformity, swelling, bruising, inability to weight bear and bony tenderness.¹
• The patient should also be assessed and examined for co-existing injuries.

Investigations

• Not everyone with an ankle injury needs to have an X-ray.
• The Ottawa rules should be applied to see whether an X-ray is indicated.
• Please refer to the further reading link below for diagrams and details explaining the Ottawa rules in relation to anatomy and tender points. The Ottawa rules are discussed further in the article Ankle injuries.
• If an X-ray is performed, anteroposterior, lateral and mortise views can be taken.^1,2
• CT and MRI scanning are sometimes needed for fracture diagnosis and assessment of ligamentous or intra-articular injuries.¹

There are a number of classification systems for ankle fractures. One of the most commonly used is the Danis-Weber classification. The classification is based on the location of the fracture and the appearance of the fibular component.

Weber Type A

• The fibula fracture (lateral malleolus fracture) is below the syndesmosis (infrasyndesmotic). If the fibula fracture is transverse, it is type I avulsion fibular fracture.
  • Weber Type A1 - there is an isolated fibula fracture
  • Weber Type A2 - there is also a medial malleolus fracture
  • Weber Type A3 - there is also a posteromedial fracture
• Mechanism of injury is internal rotation (inversion) and adduction.
• These are usually stable fractures.
• If an avulsion fracture of the fibula is undisplaced or minimally displaced, and there is no medial lesion, it may be managed in a walking cast until healed (6-8 weeks).
• Displaced/unstable fractures and those with a coexisting medial lesion need orthopaedic referral and fixation.

Weber Type B

• There is an oblique fracture of the lateral malleolus at the level of the syndesmosis with or without rupture of the tibiofibular syndesmosis and medial injury (either medial malleolus fracture or deltoid ligament rupture).
  • Weber Type B1 - there is an isolated lateral malleolus fracture
  • Weber Type B2 - there is also a medial injury (medial malleolus fracture or deltoid ligament injury)
  • Weber Type B3 - there is also a medial lesion and a fracture of the posterolateral tibia
• Mechanism of injury is external rotation (eversion) with a supinated foot.
• These fractures can be unstable.
• Stable Weber B fractures may be suitable for non-operative treatment.
• Orthopaedic referral and assessment is suggested.

Weber Type C

• These fractures occur above the syndesmosis.
• There is a high fibular fracture with rupture of the tibiofibular ligament and a transverse avulsion fracture of the medial malleolus. There is also rupture of the tibiofibular syndesmosis.
  • Weber Type C1 - there is a simple diaphyseal fracture of the fibula
  • Weber Type C2 - there is a complex diaphyseal fracture of the fibula
  • Weber Type C3 - there is a proximal fracture of the fibula
• Mechanism of injury is adduction or abduction with external rotation (eversion).
• These fractures are usually unstable, requiring operative intervention.

• Pilon fracture: a fracture of the distal tibial metaphysis and also disruption of the talar dome. The talus is 'driven' into the tibia as may happen in a fall from a height or a foot braced against the floor of a car in a collision. The fracture may be open. There may be associated injuries, e.g. spinal compression fractures or pelvic injury.^1,4
• Maisonneuve fracture: the combination of a proximal fibular fracture with a medial malleolar fracture or disruption of the deltoid ligament. There may also be disruption of the syndesmosis.^1,5
• Snowboarder's fracture: this is a fracture of the lateral process of the talus produced by dorsiflexion and inversion of the ankle. The injured person complains of lateral ankle pain. The fracture may not be evident on X-ray and may need CT scanning for diagnosis.¹
• Pott's fracture:⁶ this is a term that is not used so much now. It is an old classification system for ankle fractures and loosely refers to fractures and fracture-dislocations of the distal tibia and fibula (bimalleolar fractures). Pott originally described a partial dislocation of the ankle with a fracture of the distal fibular shaft and rupture of the medial ligaments of the ankle. The Pott's classification has now largely been replaced by the Weber and other classification systems.

• Exclude further injuries and manage any appropriately.
• Determine if the fracture is stable. Unstable fractures include any fracture-dislocation, any bimalleolar or trimalleolar fracture, or any lateral malleolar fracture with significant talar shift.¹
• If neurovascular compromise is evident, emergency reduction of the fracture is needed with maintenance of the reduction. If there is no compromise, reduction should be left to an orthopaedic surgeon.
• Any open fracture should be covered with a wet, sterile dressing. Consider tetanus status and antibiotic prophylaxis.
• If there is a simple, non-displaced, uncomplicated lateral malleolar fracture, this may be managed in the Accident and Emergency department with a cast and orthopaedic outpatient follow-up.¹
• Other ankle fractures should be referred for urgent orthopaedic assessment.
• A vascular surgical opinion may be needed if there is neurovascular compromise.
• Analgesia should be prescribed as required. There is debate as to whether NSAIDs impair fracture and ligament healing.¹

• Infection
• Compartment syndrome
• Vascular compromise and foot ischaemia
• Deep vein thrombosis (secondary to immobilisation)
• Fracture non-union and malunion
• Osteoarthritis (especially talus fractures)
• Reduced movement at the ankle (calcaneal fractures can compromise inversion and eversion)
• Ankle fractures involving the growth plate in children can lead to deformity and growth disturbance¹