Are talus fractures common?

Talus fractures are relatively uncommon, accounting for about 3% to 6% of all foot fractures and roughly 1% of all fractures in the body. They are the second most common tarsal fracture after calcaneal fractures. As snowboarding has become more popular, the incidence of ankle fractures in snowboarders has been rising.

Why are talus fractures prone to avascular necrosis?

About 60% to 70% of the talar surface is covered by articular cartilage, leaving only about 40% of the surface available for vascular perfusion, and the talus has no muscle origins or attachments, so avascular necrosis is a risk after fracture. The main blood supply to the talus comes from the posterior tibial, anterior tibial, and peroneal arteries, and this anastomosis is complete in only about 60% of people.

What situations tend to cause a talus fracture?

Fractures of the talar head and neck are usually caused by high-energy trauma such as motorcycle accidents, often occurring with excessive dorsiflexion of the foot combined with axial load through a fixed tibia. Acute dorsiflexion-inversion injuries related to snowboarding can lead to lateral process fractures.

What symptoms occur with a talus fracture?

Patients may have localized swelling, bruising, and tenderness, and ankle and foot range of motion is usually limited with pain on activity. Clinically, the surrounding neurovascular function should be checked, including the foot pulses and skin perfusion.

How is a talus fracture diagnosed?

According to the Ottawa Ankle Rules, X-rays should be obtained if the patient cannot bear weight or has tenderness over the posterior edge of the medial or lateral malleolus. CT is well suited to assessing posterior process, lateral process, and posteromedial process fractures and to evaluating the degree of displacement and comminution, while MRI can help distinguish ligament injury or assess whether surgery is needed.

Talus Fractures: From Anatomy to the Challenges of High-Risk Sports

A talus fracture is a relatively uncommon injury that usually affects the talar neck, the lateral process, or the osteochondral part of the talar dome, though rare stress fractures of the talus can also occur.

The talus is the bone that forms the lower part of the ankle joint (the tibia and fibula form the upper part), and the ankle joint allows the foot to move up and down. The talus also sits on top of the calcaneus (heel bone), and together the talus and calcaneus form the subtalar joint, which allows the foot to move inward and outward.

Most commonly the talus fractures at its middle portion, the so-called neck, which lies between the body of the talus and the head located further down toward the foot; the body sits beneath the tibia. Talar neck fractures make up 50% of talus fractures, talar body fractures 40%, and talar head fractures 5% to 10%. One common type of talar body fracture is the Shepherd fracture, a fracture of the posterior tubercle. The snowboarder’s ankle fracture is the second most common type of talar body fracture, and is mainly a lateral process fracture.

Epidemiology

Talus fractures account for about 3% to 6% of all foot fractures and roughly 1% of all fractures in the body, and are the second most common tarsal fracture after calcaneal fractures.
As snowboarding has become more popular, the incidence of snowboarder’s ankle fracture is rising.

Pathophysiology

About 60% to 70% of the talar surface is covered by articular cartilage, forming seven distinct joint surfaces. The talus has no muscle origins or attachments, and its stability is provided by the surrounding bones and ligamentous attachments. Because only about 40% of the surface is available for vascular perfusion while the rest is covered by articular cartilage, talus fractures are prone to avascular necrosis.
The talar neck is the only part of the talus that lies largely outside the joint capsule.
The tibiotalar joint is responsible for plantarflexion/dorsiflexion of the hindfoot, while the subtalar joint provides inversion/eversion of the hindfoot.
The talus bears axial load and is the joint with the highest load per unit area in the body.
The three main arterial sources to the talus are the posterior tibial artery (PTA), the anterior tibial artery (ATA), and the peroneal artery (PA). The PTA gives off the artery of the tarsal canal, which supplies the deltoid branch. These two branches are the main blood supply to the body of the talus. The artery of the tarsal canal continues along the sulcus tali on the inferior surface of the talus and anastomoses with the artery of the tarsal sinus (a branch of the peroneal artery). This anastomosis is complete in only about 60% of people.

Risk Factors

Fractures of the talar head and neck are usually caused by high-energy trauma, such as motorcycle accidents.
Acute dorsiflexion/inversion injuries related to snowboarding can lead to lateral process fractures.

History

Talar neck fractures occur with excessive dorsiflexion of the foot and axial load through a fixed tibia.
Compression fractures of the talar head can result from a load transmitted through the calcaneus against the talus.
Shear fractures of the talar head can result from an axial load transmitted through the navicular.
Anterolateral osteochondral fractures usually accompany an inversion-dorsiflexion injury of the foot, while posterolateral osteochondral fractures are associated with plantarflexion, inversion, and external rotation.

Physical Examination

Patients with a talus fracture may have localized swelling, bruising, and tenderness.
Ankle and foot range of motion is usually limited, with pain on activity.
The surrounding neurovascular function should be checked, including the foot pulses and skin perfusion.

Differential Diagnosis

Osteochondral fracture of the talar dome
Calcaneal fracture
Lateral process fracture of the talus
Medial ankle sprain with a proximal fibular fracture (Maisonneuve fracture)

Diagnostic Tools

According to the Ottawa Ankle Rules, X-rays should be obtained if the patient cannot bear weight or has tenderness over the posterior edge of the medial or lateral malleolus. Standard views include anteroposterior (AP), lateral, and the Canale view; take care not to mistake an os trigonum for a fracture.
CT: well suited to assessing posterior process fractures, lateral process fractures, and posteromedial process fractures, and for determining the degree of displacement, the degree of comminution, and the state of the joint.
MRI: especially useful for cases where it is necessary to distinguish a partial ligament injury from a complete tear, or where surgery is being considered.
Ultrasound: can serve as an adjunct examination to check the condition of the surrounding ligaments.

Initial Treatment

Use the RICE principle: rest, ice, compression, and elevation of the limb to ease acute symptoms.
If the fracture is non-displaced (under 2 mm), a short-leg cast can be used for 6 to 12 weeks with avoidance of weight-bearing.
Stress fractures usually need 3 to 6 weeks of non-weight-bearing immobilization, followed by a gradual return to activity.
Acetaminophen can be used early on to ease pain.
Non-steroidal anti-inflammatory drugs (NSAIDs) can be used to control inflammation and pain, though their effect on fracture healing remains debated.
Severe pain may require opioid medication, but only for short-term use.

Additional Treatment

Physical therapy: can be introduced during rehabilitation, including range-of-motion, strength, and proprioception training.
For stress fractures, treatment may include non-weight-bearing immobilization and a rehabilitation program with gradually increasing activity.
If avascular necrosis develops, conservative treatment can be used, with progressive weight-bearing started based on X-ray findings.

Surgery

For displaced fractures, surgical intervention is needed to avoid arthritis and avascular necrosis.
Suitable surgical options include open reduction and internal fixation (ORIF) and arthroscopic removal of loose bodies.
After surgery, a short-leg cast should be considered, with weight-bearing restricted until the fracture heals.

Follow-Up

With non-surgical treatment, X-rays should be taken every two weeks to confirm the alignment and healing of the fracture.
A walking boot can be used during healing to protect the area and support early functional recovery.
A gradual return to sport should be based on functional status and X-ray evaluation.

Prognosis

Most patients have a good prognosis with appropriate treatment, though there may be a risk of early arthritis.
The success rate of surgical treatment is high, especially when the fracture is well reduced.
Failure to treat promptly or correctly can lead to persistent pain and functional limitation.
Possible complications include:
AVN (avascular necrosis): in unstable talus fractures, the blood supply to the bone can be affected at the time of injury, and bone cells die without blood supply, leading to increased pain in the bone.
Post-traumatic arthritis: arthritis that develops after injury; even if the bone heals normally, the cartilage that protects the bone may be damaged, leading to pain and stiffness over time.
Subtalar arthritis: among patients treated non-operatively or operatively, 45% with lateral process fractures develop it.

References

https://www.ncbi.nlm.nih.gov/books/NBK539687/
https://www.orthobullets.com/trauma/1049/talus-fracture-other-than-neck
https://orthoinfo.aaos.org/en/diseases—conditions/talus-fractures
Practice Guideline Injury. 2021 Nov;52(11):3192-3199.