Dislocated Ankle (Ankle Dislocation)

• An isolated dislocated ankle is a rare injury. Usually, there is an associated fracture of the bones that make up the ankle.
• The ankle dislocates as a result of a fall, motor-vehicle crash, or sporting injury.
• In addition to the bony injury, there can be damage to blood vessels, nerves, and skin.
• The diagnosis is often made clinically.
• The emergency treatment is to reduce the dislocation as soon as possible and then splint the ankle to prevent further damage.
• Orthopedic or podiatric consultation is usually required since surgery may be required depending upon the patient's situation.
• Arthritis is a common complication of an ankle dislocation.
• Most dislocated ankles result from accidental injury and are difficult to prevent.

The ankle is a hinge joint that connects the lower leg to the foot. The tibia and fibula of the leg come into contact with the talus of the foot, forming the ankle mortise. The majority of the weight bearing in the ankle occurs between the tibia and talus. While the shape of the mortise helps align the ankle joint, the surrounding ligaments are very important in providing stability.

Picture of a dislocated ankle

A dislocated joint describes the situation where the bones that come together to form a joint no longer maintain that normal relationship. In the ankle, it means that the tibia and talus no longer maintain their normal anatomic relationship.

Most commonly, a dislocated ankle is associated with fractures of the distal ends of the tibia and fibula (called the malleolus) in association with damage to the ligaments that help support the ankle joint. Less commonly, isolated ligament injuries can result in the dislocation.

Ankle dislocations do not happen spontaneously but are a result of a trauma. Forces are placed on the ankle that cause the bones to fracture or the ligaments to tear, resulting in the dislocation injury.

The ankle is an inherently stable joint and the direction of the dislocation depends upon the position of the foot and where the force arises. Ankle dislocations are more often associated with fractures of the bones that make up the joint.

Common causes of dislocations are include falls, motor-vehicle crashes, and sports injuries.

The most common type of ankle dislocation is posterior, where the talus moves backward in relation to the tibia. For this to occur, the foot needs to be plantar flexed (the toes are pointing downward) when the injury occurs. The ankle is either forced inward from the outside (inversion) or outward from the inside (eversion), tearing the ligaments and tissues that hold the ankle stable.

Anterior dislocations, where the talus is pushed forward, occur when the foot is fixed or dorsiflexed (where the toes are pointed upward). The force from in front of the foot pushes the tibia backward.

Lateral dislocations occur when the ankle is twisted, either inverted or everted, but there are always fractures associated with either the medial or lateral malleolus or both.

Superior dislocation describes where the talus is jammed upward, into the space between the tibia and fibula, as a result of an axial loading injury. This may be due to landing on one's feet from a fall or from being in a car wreck where the foot is held firm against the brake pedal.