Fracture, Talus

Relatively uncommon fracture usually involving the talar neck, lateral process, or osteochondral fracture of talar dome

Excluding smaller osteochondral fractures, talar neck fractures account for 50% of talar fractures, talar body fractures 40%, and talar head fractures 5–10%.

Osteochondral fractures (a subset of talar body fractures) can occur in up to 6.5% of acute ankle sprains.

Shepherd fracture (posterior tubercle fracture) represents the largest single group of talar body fractures.

“Snowboarder's ankle,” a lateral process fracture, is the second most common type of talar body fracture.

Stress fractures of the talus have been reported, but are rare (1).

Talar fractures constitute 3–6% of all foot fractures, and are estimated at 1% of all fractures in the entire human body.

“Snowboarder's ankle” (lateral process fracture) appears to be increasing in frequency.

In general, fractures of the talar head and neck are the result of high-energy trauma.

Snowboarding is associated with acute dorsiflexion/inversion injuries to the ankle, which can cause lateral process fractures.

60–70% of the talar surface consists of cartilage, accommodating 7 different articulations.

The talus has no muscular insertions or origins, and is held in place by its osseous neighbors and constraining ligamentous attachments.

The talar neck is the only section of the talus that is primarily extra-articular (2).

The tibiotalar articulation is responsible for hindfoot motion in the plantar/dorsiflexion plane; the subtalar joint provides hindfoot inversion/eversion motion.

The talus transmits axial force.

The tibiotalar joint has more loads per unit area than any other joint in the body (3).

Only 40% of the talus can be perfused by blood vessels. The other 60% is covered by articular cartilage. As a result, talus fractures are at a high risk of avascular necrosis (4).

Fractures of the talar head and neck usually are found after high-velocity trauma, eg, motorcycle accidents.

Fractures of the talar neck occur as a result of hyperdorsiflexion and axial loading of the foot against a stationary tibia.

Crush fractures of the talar head occur via a compressive load through the calcaneous sustentaculum tali.

Shear fractures of the talar head occur via an axial load through the navicular (5).

Anterolateral osteochondral fractures are associated with an inversion-dorsiflexion injury of the ankle.

Posterolateral osteochondral fractures are associated with plantar flexion, inversion, and external rotation of the ankle.

Lateral process fractures are the result of ankle dorsiflexion, inversion, and external rotation (6).

Chronic osteochondral fractures present with pain following an adequate healing time for ligamentous injury, complaints of ankle “giving out,” catching, or locking up.

Talar head fractures cause swelling and tenderness at the talonavicular joint.

Talar neck fractures present with swelling and tenderness of the proximal dorsal foot. With displaced fractures, the normal ankle contours will be changed.

Acute inversion injuries of the ankle that remain painful after conservative treatment should make the clinician suspicious for osteochondral lesion of the talus or a lateral process fracture.

Thoracolumbar spinal fractures have been found in association with fractures of the talar neck and talar body (4).

Lateral talar process fractures have the same symptoms as an acute sprain of the anterior talofibular ligament. Findings may include tenderness inferior and anterior to the tip of the lateral malleolus, associated with pain on active and passive range of motion of the ankle and subtalar joints.

Acute osteochondral fractures present with edema, ecchymosis, range of motion limited by guarding, and pain to palpation.

Displaced talar neck fractures can lead to skin necrosis due to significant stretching of the soft tissues (4).

825.21 Fracture of astragalus, closed

825.31 Fracture of astragalus, open