Ankle Fractures

Also Known as:

Pott’s fracture.

Ankle fractures and fracture-dislocations are common injuries. Numerous bones around the ankle can be fractured.

Mechanism of Injury

Ankle fractures usually arise as a result of indirect forces, with the foot either being externally rotated, everted, inverted, or less commonly internally rotated on the tibia.

The important factor in ankle fractures is the stability of the ankle mortice. If the mortice is stable, that is to say no abnormal movement of the talus is possible, the injury is usually easily managed. The aim of treatment is to protect the ankle until healing has occurred. If however the mortice is disrupted, it must then be reconstructed and held until bone and soft tissue healing is complete.

Classification

Two main classification systems exist:

• Lauge-Hansen classification
• Danis and Weber’s classification (1991)

Lauge-Hansen classification

This classification system uses 2 words: the first word describes the position of the foot, while the second word describes the motion of the talus (foot) with respect to the leg.

• Supination-adduction - transverse fracture of fibula / tear of collateral ligaments ± vertical fracture of the medial malleolus
• Supination-eversion (external rotation) - accounts for 40% to 70% of all ankle fractures.
• Disruption of the anterior tibiofibular ligament
• Spiral oblique fracture of the distal fibula
• Disruption of the posterior tibiofibular ligament or fracture of the posterior malleolus.
• Fracture of the medial malleolus or rupture of the deltoid ligament
• Pronation-abduction - accounts for less than 5% of all ankle fracture
• Transverse fracture of the medial malleolus or rupture of the deltoid ligament
• Rupture of the syndesmotic ligaments or avulsion fracture of their insertion(s)
• Short, horizontal, oblique fracture of the fibula above the level of the joint
• Pronation-eversion
• Transverse fracture of the medial malleolus or disruption of the deltoid ligament
• Disruption of the anterior tibiofibular ligament
• Short oblique fracture of the fibula above the level of the joint
• Rupture of posterior tibiofibular ligament or avulsion fracture of the posterolateral tibia
• Pronation-dorsiflexion (pilon or vertical fractures)
• Fracture of the medial malleolus
• Fracture of the anterior margin of the tibia
• Supramalleolar fracture of the fibula
• Transverse fracture of the posterior tibial surface.

Danis and Weber’s classification (1991)

This classification system is based upon the position of the fibular fracture in relation to the ankle joint.

• Type A - avulsion fracture of fibula below level of tibio-fibular syndesmosis ± shear fracture of the medial malleolus
• Type B - oblique fracture of the fibula at level of syndesmosis ± fracture of the medial malleolus / tear of deltoid ligament
• Type C - fracture of the fibula above the level of syndesmosis ± medial injury + tear of inferior tibio-fibular ligament and interosseous membrane

Clinical Features

The patient complains of pain following an injury. The ankle is swollen, may be deformed and tenderness may be found on both sides of the ankle.

X-rays are needed to confirm the diagnosis: AP, lateral and half oblique. The levels of fibular fractures are best viewed in lateral view.