Syndesmosis Ankle Sprains

Ankle sprains are the most common soft-tissue injury of the lower extremity. Approximately 85% of all ankle injuries involve ligament sprains. Among the various ligaments surrounding the ankle, the majority of injuries affect the ligaments on the lateral side, particularly the anterior talofibular ligament. Severe lateral ankle injuries may also involve the calcaneofibular ligament.

While lateral ankle sprains are the most frequent ligament injuries, they are not the only ones. Failure to identify other types of ligament injuries, such as syndesmosis sprains, can lead to inappropriate treatment and prolonged disability.

The ankle region contains numerous joints that require many ligaments to maintain stability. The ankle has numerous joints, but the main joints are created by connections between the tibia, fibula, talus and calcaneus. The main joint of the ankle is the talocrural joint. It is the joint where the distal tibia and fibula articulate with the talus. There is significant dorsiflexion and plantar flexion movement at this joint. You don’t hear about it much, but there is also a joint between the distal tibia and fibula here. It is the distal tibiofibular syndesmosis.

A syndesmosis is a fibrous joint with minimal movement, where two bones are connected by ligaments or another type of connective tissue. The syndesmosis in the ankle where sprains can occur is the distal tibiofibular syndesmosis. This tough fibrous connection holds the distal ends of the tibia and fibula together.

The distal tibiofibular syndesmosis is composed of several ligaments and connective tissues. They include the lower margin of the interosseous membrane, the interosseous ligament, the anterior tibiofibular ligament, the posterior tibiofibular ligament, and the transverse tibiofibular ligament (Figure 1). Because the syndesmosis ligaments are more proximal than the commonly injured lateral ankle ligaments, injuries to this area are often referred to as high ankle sprains.

Figure 1
The distal tibiofibular syndesmosis

Injuries to the syndesmosis are typically caused by excessive rotation of the ankle (such as adduction or abduction of the foot), extreme dorsiflexion, or a combination of dorsiflexion with rotation.

Syndesmosis sprains often occur in sports played on turf, particularly when cleated shoes are involved. For instance, an athlete’s cleat may become stuck in the turf, immobilizing the ankle. If the athlete falls forward (resulting in dorsiflexion) while simultaneously turning to the side (causing rotational stress), a syndesmosis injury is likely.

Unlike lateral ankle ligament injuries, syndesmosis sprains are harder to detect because the ligaments are deeper and covered by other soft tissues, making palpation difficult. As a result, special orthopedic tests are often necessary to identify syndesmosis sprains.

In addition to gathering key information from the client’s history, visual examination, and range-of-motion assessments, two specific tests—the squeeze test and the external rotation stress test—can be used to evaluate syndesmotic injuries. During the squeeze test, the practitioner gently squeezes the distal tibia and fibula together, just above the syndesmosis joint. If this action reproduces the client’s pain, damage to the syndesmosis ligaments is likely.

In the external rotation stress test, the practitioner stabilizes the tibia and fibula with one hand while using the other hand to gently externally rotate (abduct) the foot. The foot should be in a neutral or slightly dorsiflexed position during the rotation. If this movement triggers the client’s primary pain, it strongly suggests involvement of the distal tibiofibular syndesmosis.

It is crucial to identify an injury to the ankle syndesmosis correctly, as not recognizing a syndesmosis injury may lead to inappropriate treatment and prolonged disability. If your client has sustained an ankle injury, it is essential to determine which tissues are primarily affected so you can provide the appropriate treatment or refer them for further care. Untreated syndesmosis sprains can lead to chronic ankle instability if not accurately evaluated and managed.

You can learn more about syndesmosis sprains and numerous other lower extremity disordes in our comprehensive orthopedic medical massage courses. Come join us and see what a dramatic transformation this can be for your clients.