Comminuted fracture of talus

In most cases, comminuted fractures of the talus are caused by falling from a height or violent impact from external force. Such fractures are very damaging to the bones. In addition to feeling severe pain, the fracture site is prone to deformity and swelling, so timely medical treatment should be sought.

Causes

Talus body fractures are mostly caused by falling from a height or violent direct impact. The talus body can fracture in the transverse plane or form a longitudinal split fracture. Fractures may be linear, stellate, or comminuted. Talar body fractures often affect the ankle joint and subtalar joint. Although the displacement is very slight, it can lead to a stepped deformity of the above-mentioned joints and eventually produce traumatic arthritis. Therefore, the prognosis of talar body fractures is worse than that of talar neck fractures.

1. Fracture of the neck and body of the talus

Most of them are caused by falling from a height, with the heel landing on the ground, and the force pushing down along the tibia. The reaction force pushes upward from the heel, and the front part of the foot is strongly dorsiflexed, causing the front edge of the lower end of the tibia to insert between the neck and body of the talus, causing fractures of the talar body or talar neck, the latter being more common. If the foot is forcefully inverted or everted, the talus may fracture or dislocate. After a talar neck fracture, the talar body may suffer from ischemic necrosis due to circulatory disorders.

2. Posterior process fracture of talus

It is caused by forceful plantar flexion of the foot being impacted by the posterior edge of the tibia or the superior edge of the calcaneal tuberosity.

3. Blood supply to the talus

(1) The posterior tibial artery is divided into three branches. One of the calcaneal branches of the posterior tibial artery supplies the posterior tubercle of the talus. The tarsal artery supplies the middle and lateral thirds of the body of the talus and anastomoses with the tarsal sinus artery, a branch of the anterior tibial artery. A triangular branch arises approximately 5 mm from the tarsal artery and supplies the medial 1/3 of the talus.

(2) The anterior tibial artery can be divided into three branches, two of which branch inward and anastomose with the triangular branch below the medial malleolus. The tarsal sinus artery originates outward and supplies the lower half of the talar head and part of the talar body. The dorsal artery of the dorsalis pedis directly supplies the upper and inner parts of the neck and head of the talus.

(3) The peroneal artery has two branches, one of which anastomoses with the calcaneal branch of the posterior tibial artery and the other anastomoses with the tarsal sinus artery.

Based on the above images of talar fractures, it can be seen that the medial and superior half of the talar head is supplied by the dorsal artery of the dorsalis pedis artery, the lateral and inferior half is supplied by the tarsal sinus artery, the middle and lateral 1/3 of the talar body is supplied by the tarsal canal artery, and the medial 1/3 is supplied by the triangular branch. The tarsal sinus artery also supplies a small part of the lateral and inferior part, and the posterior tubercle of the talus is supplied by the calcaneal branch of the posterior tibial artery.

Although the talus has a relatively rich blood supply, most of the surface of the talus is covered by articular cartilage and has no muscle attachment; the blood vessels are relatively concentrated at the site where they enter the talus and are easily damaged; the talus is a cancellous bone and will be compressed and damage the blood vessels during trauma, so ischemic necrosis is likely to occur in fractures or dislocations.

treat

Except for the neck part of the talus, which has more ligaments attached and slightly better blood circulation, the upper, lower and front directions are all articular surfaces connected to the adjacent bones and lack sufficient blood supply. Therefore, attention should be paid to accurate reduction and strict fixation, otherwise the incidence of aseptic bone necrosis and nonunion will be high. Take appropriate treatment measures according to the type of fracture and specific circumstances.

1. Non-displaced fractures

The fracture should be fixed with a plaster boot for 6 to 8 weeks, and try not to force weight support before the fracture is firmly healed.

2. Displaced fractures

Talus head fractures are often displaced dorsally and can be reduced by manipulation. Pay attention to fixing the foot in plantar flexion with the distal end facing the proximal end, and fix with a plaster boot for 6 to 8 weeks. After the fracture is basically connected, it can be gradually corrected to the 90° functional position of the ankle joint and then fixed for 4 to 6 weeks, which may achieve a more solid healing. Try not to force weight bearing too early. If there is a large separation in the fracture of the talus body, manual reduction can be successful, but strict fixation for 10 to 12 weeks is required.

If manual reduction fails, calcaneal traction can be used for 3 to 4 weeks, followed by manual reduction. Then use a plaster boot to strictly fix it for 10 to 12 weeks. However, when the talus body is comminuted or split, the upper and lower articular cartilage surfaces are often damaged, and the incidence of traumatic arthritis after healing is high, and the recovery is often not very satisfactory.

If the posterior process of the talus is displaced, the fracture fragment can be removed if it is not large. If the fracture fragment is large and affects the joint surface more, it can be fixed with Kirschner wires and a plaster boot for 8 weeks.

3. Failure of closed reduction often requires surgical incision and internal fixation with screws

Talar neck fractures account for approximately 30% of talar fractures. When falling from a height, the foot and ankle dorsiflex at the same time, and the talar neck hits the front edge of the distal tibia, causing a vertical fracture. There are three types:

(1) Type I: Vertical fracture of the talar neck with little or no displacement.

(2) Type II talar neck fracture combined with subtalar joint dislocation. After the talar neck fracture occurs, the foot continues to dorsiflex, the talar body is fixed in the ankle cavity, and the rest of the foot is excessively dorsiflexed, resulting in subtalar joint dislocation.

(3) Type III talar neck fracture combined with talar body dislocation. After the talar neck fracture, the external dorsiflexion force continues to act, causing the talar body to rotate inward and posteriorly and dislocate, and lock behind the talar process, often accompanied by a medial malleolus fracture. It is usually an open injury.