Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Talus Fractures


KEY FACTS

  • The talus is the 2nd most commonly fractured tarsal bone (after the calcaneus).

  • The blood supply of the talus can be tenuous, as there are limited spaces at which vessels can enter the bone, given its morphology and participation in multiple joints.

    • The blood supply of the talar body is retrograde through the talar neck.

  • Although there is great concern for osteonecrosis after talar neck and body fracture, posttraumatic arthritis is a more common outcome.

    • Posttraumatic arthritis is likely related to the initial severity of the injury but also the quality of the ultimate reduction, and every effort should be made for as anatomica reduction as possible.

  • For the rare posteromedial talar body fracture, it is important to understand that medial malleolar osteotomy is not helpful and does not improve visualization, as the fracture line is typically posterior to the medial malleolus.

  • Lateral process talus fractures are increasingly common and should be considered in the setting of an acute ankle sprain.

  • While nonunion is rare after talar neck fracture, malunion, especially varus malunion, is not. Compression of a comminuted medial talar neck should be avoided in an effort to minimize the risk of this complication.

A male patient in his mid 20s was skateboarding when he sustained an injury to his right ankle. Once he was able to get radiographs, a large lateral process talus fracture was seen.

CT scan of the same patient shows a large displaced fragment. In this young patient, the concern for posttraumatic arthrosis is high, and the decision was made to perform open reduction internal fixation.

The bony fragment was reduced though an Ollier-type lateral incision. Two 2.0-mm noncannulated screws were used with lag by technique, provided excellent compression for this anatomic reduction.

Lateral view shows the relative anterior to posterior position of the screws. Given the nature of the injury, bicortical fixation is not possible, and some surgeons will consider headless screws if more traditional screws do not provide adequate fixation. These headed screws compressed the fracture well.

Background

  • Talus fractures fall into a difficult middle ground of injuries that are infrequent enough that they are difficult to study but frequent enough and often severe enough that they cause significant functional morbidity for a number of people that is not insignificant.

    • Injuries are typically high energy, such as a fall from a height or a motor vehicle accident. As with any high-energy injury, initial evaluation consists of a thorough clinical examination with a search for other injuries.

    • As the talus is mostly covered with articular surface, any significant fracture displacement requires a joint subluxation or dislocation. In other words, most displaced talar fractures are also dislocations.

    • All dislocations should be reduced emergently to prevent further soft tissue injury. Historically, these injuries, especially talar neck fractures, were treated emergently, as this was thought to decrease the risk for osteonecrosis (ON), although more recent data suggests that this is likely untrue.

    • Radiographic examination consists of anteroposterior, lateral, and mortise images of the ankle and anteroposterior, lateral, and oblique views of the foot. Canale views are beneficial and can increase the ability to visualize the talar neck.

    • Computed tomography (CT) scanning of talus fractures is crucial; it aids in understanding the extent of injury as well as being critical for surgical planning. Imaging studies should be carefully reviewed for the presence of other fractures of the foot or ankle.

Anatomy

Introduction

  • “Talus” comes from taxillus, Latin, which means dice. The Romans used the heel bone of the horse to make dice. The Greeks used the 2nd cervical vertebrae of sheep to make dice, and astragalus is vertebra in Greek.

  • 2/3 of the talus is covered by articular cartilage. There are no tendon or muscular attachments to the talus, but many muscles cross the talus, all of which also influence the subtalar and other hindfoot joints.

  • It is a weight-bearing bone that transfers all the weight from the foot to the tibia and fibula. For descriptive purposes, it is divided into the body, neck, and head.

Talar Body

  • The body includes the talar dome and posterior facet, which make up the ankle and subtalar joints, respectively. The superior portion of the body is articular. It is shaped like a pulley in the coronal plane with the trochlear portion lying offset more medially. In the axial plane, the superior surface is shaped like a trapezoid with the anterior portion wider than the posterior.

  • The lateral talus becomes somewhat triangular and articulates with the fibula. The perimeter of the lateral articular portion is called the lateral process. It serves as the site of attachment for the lateral talocalcaneal ligament as well as the anterior and posterior talofibular ligaments. The undersurface of the lateral process makes up the lateral portion of the posterior facet of the subtalar joint, so that most lateral process fractures are intraarticular.

  • The medial portion of the talus has a large articular surface for the medial malleolus. In the anterior nonarticular area, there are vascular foramina. The posterior body serves as insertion for the deep deltoid ligament.

  • The posterior process of the talus is made up of posteromedial and posterolateral tubercles, between which lies a groove for the flexor hallucis longus tendon.

Talar Head

  • The head primarily articulates with the navicular anteriorly. Inferiorly in the head are the anterior and middle subtalar facets, which are sometimes fused into a single facet. These joint surfaces make a socket in which the talar head rotates (or, more accurately, the socket rotates around the talar head). There are attachments for the spring ligament, deltoid ligament, and sustentaculum tali.

Talar Neck

  • The neck lies between the body and head and has multiple ligamentous attachments. It is oriented 15-20° medial to the talar body and lies directly over the sinus tarsi and tarsal canal. This region has numerous capsular attachments and vascular foramina.

Vascular Anatomy

  • The vascular supply of the talus has been of special interest due to association of ON with talus injuries.

    • Since 2/3 of the talus is covered by articular cartilage, and there are no muscular attachments, the blood supply is limited. There are contributions from the capsular and ligamentous attachments to the tibia, calcaneus, and navicular.

Extraosseous Arterial Supply

  • Branches of the posterior tibial, dorsalis pedis, and peroneal arteries contribute to the talus; however, there are multiple variants on the branches. There is a delicate network of anastomoses between the arteries, which envelops all the nonarticular areas of the talus.

  • The posterior tibial artery gives off the artery to the tarsal canal and a vascular plexus for the posterior process. The deltoid branch of the artery to the tarsal canal supplies the medial talar body.

  • The dorsalis pedis leads to the anterior lateral malleolar artery and branches over the superior surface of the neck to supply the head. The anterior lateral malleolar artery anastomoses with the peroneal artery supply to form the artery of the tarsal sinus.

  • The peroneal artery sends branches to the posterior process to anastomose with the posterior tibial vessels. In addition, it contributes to the artery of the tarsal sinus via the perforating peroneal artery.

  • The arteries of the tarsal canal and sinus anastomose, forming the artery of the tarsal sling. This supplies the inferior neck and lateral body. The arteries of the tarsal canal and sinus, along with the medial periosteal vessels, are the most essential supply to the talus.

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here

Related Posts