Syndesmosis Injury: The High Ankle Sprain

What Is A Syndesmosis Injury?

Syndesmosis injury, also referred to as a syndesmosis ankle sprain, or a high ankle sprain, is a more severe injury than the common lateral ankle sprain. A syndesmosis injury is estimated to occur in up to 18% of all ankle sprains. A high ankle sprain will typically result in more disability post injury and longer return to play times for athletes than the more common standard lateral ankle sprain.

What Is The Tibiofibular Syndesmosis?

The function of the tibiofibular syndesmosis is to maintain the relationship between the tibia and fibula, this syndesmosis provides stability to the ankle mortise during weight bearing activities. With regard to a syndesmosis ankle sprain this injury refers to the disruption of the bony articulation between the lower aspect of the fibula and tibia (the two shin bones). The majority of the stability of this joint between the two shin bones is provided by the ligamentous structures of the syndesmosis. There are four different ligaments that comprise the syndesmosis, disruption of some, or all of these ligamentous structures that support the articulation occurs in a high ankle sprain injury. *see the image below for a basic view of stripped back ankle anatomy and the syndesmosis ankle ligaments.

Ankle Syndesmosis Anatomy

Injuries To The Ankle Syndesmosis

Forced dorsiflexion of the ankle, external rotation of the ankle and a combination of dorsiflexion and external rotation are the most common mechanisms of injury to the ankle syndesmosis. These type of injuries are usually seen in the setting of low energy rotational injuries to the ankle joint during athletic activity. Most individuals who suffer a high ankle sprain likely participate in sports that involve planting the foot and cutting (sports requiring rapid changes of direction). Other mechanisms of injury can come from direct blows to the outside of the ankle, such impact forces when playing sport can again lead to forced external rotation of the ankle. An example of this mechanisms of high ankle sprain injury could occur when paying any of the footballing codes, a tackle gone wrong coming from the side of the body while the foot is planted on the ground and the planted foot is pushed into external rotation whilst weight bearing under the force of the tackle. It should be noted that bony injuries to the ankle joint and other ligamentous injuries of the ankle often occur in conjunction with ankle syndesmosis injuries. The detection of syndesmosis injuries relies on clinical examination referring to an understanding of the mechanism of injury making the initial suspicion of a high ankle sprain, couple with the physical assessment of the ankle. These in-clinic findings can be “backed up” with radiographic investigations to help confirm the diagnosis of a high ankle sprain.

Disclaimer: Sydney Physio Clinic provides this information as an educational service and is not intended to serve as medical advice. Anyone seeking specific advice or assistance on Syndesmosis Injury: The High Ankle Sprain should consult his or her physiotherapist, general practitioner, sports doctor, orthopedic surgeon or otherwise appropriately skilled practitioner.