Talar Neck Fracture (Aka Aviator Astralgus)

Summary

Talar neck fractures are very serious injuries.  They occur following a major force that drives the foot up against the ankle.  The ankle and foot will be swollen, painful and possibly deformed.  The nature of the fracture will typically need to be investigated by performing x-rays and a CT scan.  Most talar neck fractures are displaced and will require surgery to reposition the bones back to their original position.  Recovery requires a prolonged (6-12 weeks) period of non-weight bearing.  Complications of the injury are unfortunately common and may include ankle arthritis due to loss of blood supply to the talus, subtalar arthritis, and/or malignment of the foot.

Clinical Presentation

Talar neck fractures occurs when there is a significant amount of force applied to the sole of the foot forcing the foot to flex upwards (dorsiflex) and thereby driving the talar neck up against the front of the ankle joint. Talar neck fractures usually occur from high-energy injuries such as a motor vehicle accident where the foot is driven into the floorboard, or by falling from a substantial height. As the foot is driven forward, the talar neck is forced onto the front of the ankle creating the fracture. Historically, this injury has been called “aviator’s astralgus” (astralgus is a word meaning talus) because when pilots in World War I would crash their planes, their foot would often be driven up into the floorboards leading to a talar neck fracture.
In some instances the force can be great enough to dislocate the talar body (the back part of the talus after the fracture) out of the ankle joint posterior (behind the ankle joint). It is also possible that the bone may actually break through the skin at the time of the injury, creating an open fracture. Symptoms of a talar neck fracture include marked pain, swelling, and the inability to bear any significant weight.

Physical Examination

Patients will have swelling, localized discomfort around the ankle joint, and may or may not have a nerve injury. The foot may appear deformed in an angulated or twisted manner.

Imaging Studies

A talar neck fracture can be diagnosed via x-rays of the foot. The fracture will be identified extending through the talar neck region.  Occasionally, the fracture is undisplaced and can be difficult to read on plain x-ray. To more easily understand the fracture pattern and particularly if surgery is a possibility, a CT scan will be ordered.

Treatment

Non-operative Treatment

It is very rare for a talar neck fracture to be truly non-displaced.  However, if it is as demonstrated on the CT scan it may be treated non-surgically with non-weight-bearing and immobilization for 6-8 weeks until healing of the fracture has been documented.

Operative Treatment

The treatment of a displaced talar neck fractures is operative (talar neck ORIF) unless there is a contraindication to surgery. The goal of surgery is to return the talus to its original position prior to the fracture. Although this procedure may be challenging, it is very critical to get an anatomical reduction in order to avoid malalignment of the foot.  To optimize the chance of getting the fractured bones back exactly where they belong typically requires two incisions –one on the inside and one on the outside of the ankle.  The bones are then stabilized by screws and possibly a plate.

Potential Complications –Specific to talar neck ORIF

There are a variety of potential compilations that may occur following surgery to repair a talar neck fracture.  Most of these complications are related to the original injury itself, and not the actual surgery.  They included:

Avascular Necrosis (Osteonecrosis) of the talar body

The nature of the injury often causes a loss of the blood supply to the back part of the talus –the part that forms the lower part of the ankle called the talar body.  This can cause this bone to collapse with resulting arthritis of the ankle joint.

Subtalar Arthritis

The injury can also lead to arthritis in the joint below the talar body (the subtalar joint).

Malalignment of the foot

The position of the talar neck dictates how the rest of the foot is aligned.  If the bone cannot be restored to its original position due to bone loss or technical challenges then the foot may be malpositioned (ex. curved inwards).

Potential Complications General

There are the usual variety of potential complications which may occur following surgery to fix a talar neck fracture.  The include:

Infection

Wound healing problems

Deep Vein Thrombosis (DVT)

Pulmonary Embolism (PE)

 

Edited by Jean Brilhault, MD on February 19th 2013