Introduction

The talus, or astragalus bone, is a small bone located in the ankle, connecting the bones of the leg (the tibia and fibula) to the bones of the foot. Despite its small size, this bone is essential for proper weight distribution from the leg to the foot and for the normal range of motion of the foot.¹ Talus fractures are very rare, representing only 0.008% of all fractures in children, vs. 0.3% in adults.² 

Because of its location, the talus is very important for foot and ankle movement and function, but also for overall balance and stability.¹ In children, the talus is in majority made of cartilage, which provides much more flexibility than bone. As a consequence, children are significantly less prone to talus fractures than adults.³

Understanding talus fractures in children

What is the talus bone?

As mentioned in the introduction, the talus is a key component of the ankle joint, connecting the leg to the foot. It is made up of three adjacent parts named the head, the neck and the body. In younger children, it is mostly made of cartilage, which provides a lot of elasticity and flexibility. As children get older, the cartilage in the talus will slowly be replaced by bone by a process called ossification.

A unique feature of the talus is that it is not attached to any muscle, but rather relies on surrounding cartilage, bones, and ligaments for support and movement. Another relevant characteristic of the talus is that, unlike other bones, it is very poorly vascularised. This is an important consideration in case of injury, as the lack of blood vessels can limit the delivery of nutrients, increase healing time, and increase the risk of necrosis in case of injury.¹

How do talus fractures occur in children?

The most common location for a fracture of this bone in children is the neck, followed by the body and the head of the talus. Fractures usually occur when the foot is forcefully pushed upward (dorsiflexion), which can cause the talus neck to break as it hits the tibia (shinbone).^4,5 This injury could result from a fall, such as falling from playground equipment. Talus fractures can also occur due to sports-related injury, such as gymnastics, skateboarding or football. Car and bicycle accidents can also sometimes lead to high-impact trauma to the foot, resulting in a break of the talus. See Figure 1. 

Figure 1. Illustration of a talus fracture – Freepik [Internet]. Available from: www.freepik.com

How do talus fractures differ in children vs. adults?

Children’s bones have more flexibility and elasticity, making talus fractures less likely than in adults and usually less severe. There is also a significant difference in the healing ability between children and adults. This is in large part due to the presence of open growth plates (also called physes) in children, which influences the ability of bone tissue to regenerate and remodel.⁶ 

Accurate diagnosis and appropriate treatment of this type of injury is essential to avoid long-term consequences. Indeed, a fracture that affects the growth plate adjacent to the talus, if improperly treated, could result in permanent damage to the growth plate, with outcomes such as limb length discrepancies and deformities.⁷ 

Recognising the symptoms of a talus fracture

According to the Pediatric Orthopaedic Society of North America, the most common signs of a talus fracture in children are:

• Pain and tenderness around the ankle
• Swelling and bruising
• Inability to bear weight or walk

In more rare cases of a displaced fracture, where the bone or broken fragments have moved away from their normal location, some deformity may also be observed. Even though it is rare, severe fractures can occasionally affect nerves and blood vessels, which can cause numbness or impaired blood flow to the foot. It is therefore always essential to have the injury thoroughly examined by a medical care professional.⁸

It is important to seek medical attention when any of the signs mentioned earlier are observed, particularly if pain persists after resting. Early diagnosis is important in children due to their more rapid healing ability, which could lead to the bone starting to heal out of place. Particularly in the case of displaced fractures, prompt intervention is essential to realign the bone or fragments, limiting long-term complications such as arthritis or reduced mobility.

Diagnosis and medical evaluation

Physical examination and symptom assessment

When a doctor suspects a talus fracture, they will perform a thorough physical examination of the ankle, looking for tenderness, swelling, and limited range of motion. They will also ask details about how the injury occurred, as this can give them clues on the severity of the injury. Once these symptoms are assessed, imaging tests will bring confirmation of the diagnosis.

Imaging tests used for diagnosis

When a fracture is suspected, the first step is usually confirmation by X-ray. However, in cases where an X-ray is unclear, the next step will be either a CT (Computed Tomography) scan or an MRI. Unfortunately, the initial X-ray can sometimes miss a fracture, particularly in growing children whose bone composition can be softer, making the interpretation of the X-ray more challenging.⁵ More advanced imaging techniques are therefore sometimes necessary to detect more subtle fractures, and to assess damage to the surrounding area, particularly to the growth plate located between the shinbone and the talus.

Treatment approaches for talus fractures in children

Non-surgical treatment options

Non-surgical treatment is usually recommended when the talus fracture is not or minimally displaced.⁶ In this case, the standard of care will involve the following steps:

• Immobilisation of the foot in a cast or a splint: To limit movements and promote healing, for 6-8 weeks⁹
• Rest and activity modification: No weight bearing for several weeks, with use of crutches or a wheelchair to assist with mobility
• Monitoring for proper healing: Regular follow-up imaging to ensure proper healing of the talus

When surgery is needed

Surgical intervention is most often needed for more severe fractures to avoid long-term complications:

• Displaced fractures: the bone or bone fragments have moved out of place
• Compound fractures: the broken bone has pierced through the skin

In these less common situations, it is recommended to surgically realign the bone, which can involve the placement of pins or screws to secure the bone in its proper position.

Like any surgical procedure, there are risks and benefits to be taken into account when repairing a talus fracture. Surgery will help restore function, but recovery is significantly longer compared to non-surgical interventions. Even though the risk is minimal, any patient should be monitored for post-operative infection.

Unique considerations in treating talus fractures in children

Growth plate involvement and future bone development

A unique consideration for talus fractures in children is the proximity to the growth plate at the base of the tibia, immediately adjacent to the talus. Growth plates are areas at the end of long bones, such as the tibia, that are made up of cartilage. This cartilage contains chondrocytes that are actively proliferating, slowly increasing the length of the bone. As children grow, these plates close, the cartilage is entirely replaced by bone, and growth is halted.¹⁰

On very rare occasions, a fracture of the talus can damage the adjacent growth plate’s cartilage. In such a situation, there is a concern that this damage would lead to bony repair, which would affect future bone growth and could possibly lead to limb deformities.¹¹ For this reason, long-term monitoring of a talus fracture can be important to ensure that growth is still occurring normally.

Healing and recovery differences in children

Overall, younger children tend to heal and recover faster than adults from bone breaks, and without long-term complications. However, paediatric talus fractures, particularly if they are displaced or resulted from high-energy trauma, are significantly more likely to lead to the following complications²:

• Avascular necrosis: This happens when the talus loses its blood supply and dies
• Arthrosis (or osteoarthritis): A degenerative condition where the cartilage that surrounds and protects the bone breaks down
• Neurapraxia: Temporary nerve injury which can lead to weakness or numbness
• Further surgery is sometimes needed to address improper healing

It is important to note that avascular necrosis can be a significant complication, mostly due to the unique anatomy of the talus and its low blood supply. It is of particular concern in children, as it can halt the proper development of the ankle joint, resulting in chronic pain and long-term disability. It is therefore very important to have regular follow-ups, including imaging, to monitor for avascular necrosis and intervene quickly to prevent adverse outcomes.^2,12

Summary

Even though talus fractures are rare in children, they can occur due to falls at the playground, sports injuries, or any type of high-impact trauma. The talus is a critical bone in the ankle, responsible for weight distribution and movement. In children, it contains more cartilage as it is still growing, making fractures less common and often less severe than in adults. However, injuries involving the neighbouring growth plate of the shinbone require special attention to prevent long-term complications.

Symptoms of a talus fracture include pain, swelling, bruising, and inability to bear weight. Diagnosis typically involves a physical examination followed by imaging, usually X-rays, with CT or MRI scans used for more complex cases, where a fracture would be missed by an X-ray. Treatment depends on the severity of the fracture, with non-displaced fractures managed through immobilisation and rest, while more severe cases may require surgical intervention. Although children generally heal faster than adults, complications like avascular necrosis and joint issues can occur, especially with high-energy trauma.

Final thoughts

Talus fractures are uncommon in children, and with proper care, most recover rapidly and fully. However, parents and guardians should be vigilant and seek prompt medical attention for any ankle injuries and ensure follow-up care to detect and manage any potential complications early.