What is Talar Neck Fractures?
Fractures to the ‘talar neck’, a part of the foot bone known as the talus, are rare but can lead to severe and life-changing consequences. The talus, located in the back of the foot, enables pain-free movement of the ankle and related joints. This type of fracture is typically linked to high-energy incidents, which can cause severe injuries to the soft tissues and bones. The break is also often misplaced. As a result, such injuries can lead to permanent stiffness, deformities, and pain in the foot. In fact, it is estimated that more than 90% of individuals whose talar neck fractures move out of place, end up with foot joint disorders.
Due to the rarity of these injuries, there isn’t much high-quality research available to guide treatment strategies. Mainly, a surgical procedure known as ‘open reduction internal fixation’ is used to treat these fractures when they are misplaced. Non-surgical methods are typically only used when the fracture doesn’t move or when the patient isn’t a suitable candidate for surgery. Common complications associated with the surgical treatment of talar neck fractures include the death of bone tissue, post-trauma arthritis, and wrongly healed fractures.
The high-energy force involved often contributes to these injuries. The displacement of the fracture fragments can disrupt blood supply to the talus bone, causing the bone tissue to die. If misplacing of the medial talar neck is not recognized, it can heal wrongly and lead to a deformity. Regardless of when the fracture is fixed and how well it is reduced, a majority of these injuries eventually require a foot joint fusion surgery to relieve pain. The high-energy cause of talar neck fractures often results in significant damage to soft tissues, making post-surgical wound healing a significant concern.
What Causes Talar Neck Fractures?
The term “aviator astragalus” was first used in 1919 by Anderson to describe a specific type of foot injury. Anderson noticed a higher rate of talar neck fractures, a particular kind of foot bone breakage, among fighter pilots who had been in plane crashes during wartime.
These fractures typically happen when the foot is forced to bend upward under a lot of pressure, such as during a high-speed car accident or a fall from a high place. The fracture occurs when the harder bone of the front lower leg is pushed down and hits the softer bone in the neck of the talus, a bone in the foot.
Once the fragile neck of the talus bone breaks, the force spreads to the ligaments (tissue connecting bones) surrounding the talus. This may cause the talus to move out of place from its normal position in the ankle joint and the calcaneus, the bone found beneath the talus. This injury can be worse if the foot is also twisting. A study found that 26% of these fractures were also accompanied by a break in the inner part of the ankle bone.
Risk Factors and Frequency for Talar Neck Fractures
Fractures to the talus, a bone in the foot, rank as the second most common type of foot bone fracture. However, they’re still quite rare, making up less than 1% of all foot and ankle bone injuries. Of these fractures, about half happen to the talar neck, the part of the bone that joins the rest of the foot.
Despite their rarity, the likelihood of experiencing a talus fracture has recently increased to about 2%, possibly due to the improved survival rates for major motor vehicle and motorcycle accidents, which can often cause severe foot injuries.
Signs and Symptoms of Talar Neck Fractures
If someone has broken their talar neck, which is a part of the ankle, they usually have suffered a serious accident like a car crash or a fall. This type of injury is associated with pain in the back of the foot, bruising, and swelling. Due to the nature of these incidents, these patients could also have other injuries (to their bones, blood vessels, or soft tissues) that need immediate attention. Hence, it’s vital to perform a detailed checkup, by firstly ensuring the patient’s breathing and blood circulation are not compromised.
Doctors then assess the patient’s nerve functions and blood flow in the foot. This involves checking the pulse in two arteries in the foot: the dorsalis pedis and the posterior tibial artery, which could be felt by hand or evaluated using an ultrasound scanner. A sensory examination is also performed in areas supplied by five specific nerves: the superficial peroneal, deep peroneal, saphenous, sural, and tibial nerve.
Movement of the foot, including movements of the big toe, ankle’s upward bending (dorsiflexion), downward bending (plantar flexion), and turning inwards (inversion) and outwards (eversion) of the foot are also checked. The doctor would take note of any abnormalities in these nerve or movement tests. They also inspect the skin for scrapes or cuts that might indicate the fracture has broken through the skin.
If the fracture is indeed open (the bone is sticking out through the skin), the doctor will carefully clean the area, administer antibiotics and a tetanus shot, and set the bone in the right place if needed. They’ll also apply a temporary splint to the foot which can relieve pain and reduce pressure on the surrounding soft tissues. If the talus, a bone in the ankle, is pushed out of its place, it will also be washed and repositioned if feasible.
Testing for Talar Neck Fractures
To evaluate a talar neck fracture, which refers to a break in the neck of the talus bone in your ankle, doctors will typically utilize a standard x-ray to get different views of the fracture, including a highly specific view known as a Canale view. This particular view gives the best image of the talar neck and is achieved by positioning the foot and the x-ray beam at precise angles.
Advanced imaging technology, such as Computed Tomography (CT) scans, has significantly improved the assessment of these types of fractures. This is because they offer a more detailed visualization of the complex structure around the joint. CT scans are also the go-to technique to gauge the extent of displacement (how much the bone has moved from its original place), the condition of the joint surfaces, and the level of fragmentation of the fracture.
Magnetic Resonance Imaging (MRI) is generally not used for talar neck fractures in their initial stages. On the other hand, three-dimensional (3D) reconstructions of CT images provide additional information about the alignment and plan for surgery.
In 1970, a classification method for talar neck fractures was proposed by Dr. Leland Hawkins, known as the Hawkins Classification of Talar Neck Fractures. This system classifies the fractures based on how much the fracture has shifted and where a joint might have been dislocated around the talus bone. The more severe the type according to this classification, the higher the risk of a condition known as osteonecrosis (which means the death of bone tissue due to lack of blood supply).
Hawkins classification includes:
- Hawkins I: no shift in the fracture
- Hawkins II: fracture with associated dislocation of the subtalar joint (one of the joints in your ankle)
- Hawkins III: fracture with associated dislocation of the subtalar and tibiotalar joints
- Hawkins IV: fracture with associated dislocation of the subtalar, tibiotalar, and talonavicular joints (all the joints in your ankle)
The likelihood of developing osteonecrosis in each Hawkins category ranges from 0% to 13% for Hawkins I to 70% to 100% for the most severe type, Hawkins IV.
Treatment Options for Talar Neck Fractures
Displaced fractures in the neck of the talus bone, a small bone in the ankle, are typically treated with a method known as open reduction and internal fixation. Non-surgical treatment is only used for non-displaced injuries, or in cases where the patient is not fit for surgery. Initial non-surgical treatment involves immobilizing the foot with a splint and then switching to a short leg cast once the swelling goes down. Sometimes an external brace is used to temporarily stabilize the break and closely monitor the surrounding soft tissues.
In surgery, the objective is to reposition the bone fragments as accurately as possible, which can be quite challenging if the fracture is severely displaced, broken into numerous pieces, or bent out of shape. Even a small misalignment of 2mm on the joint surface can create abnormal pressures on the bone.
Typically, the surgery involves making two incisions from the front and the side of the foot to achieve a good alignment of the fracture. Alternatively, an approach from the side of the foot (sinus tarsi) can be used which provides a better view of certain areas of the ankle. Additional procedures like cutting the malleolar bone can be done to help visualize the talar neck and body.
The exact method used surgically depends on many factors including the nature of soft tissues, the type of fracture, and any accompanying injuries. Different methods of securing the bone fragments, using screws or plates, or a combination of both, have been reported. Usually, a combination of plates and screws are used in 96% of talar neck fractures.
Inserting screws lengthwise, especially on the inner side of the foot, is generally avoided. This is because too much pressure through such an arrangement in a badly fractured bone can lead to deformity. Studies comparing different methods of fixation didn’t find one to be superior over the others in terms of holding the fragments together or providing stability.
Historically, treating fractures in the neck of the talus was considered urgent, similar to open fractures or irreducible dislocation, in a bid to preserve blood supply to the talus. However, recent studies propose conflicting opinions. Presently, it is thought that the risk of bone death related to disruption of blood supply is more related to the extent of displacement at the time of injury. It’s important to note that while it may be acceptable to delay fixation, it is not advisable to delay repositioning of fractured bone fragments.
What else can Talar Neck Fractures be?
When doctors are trying to diagnose a talar neck (ankle) fracture, they also consider other conditions that might be causing the pain or deformity. These include:
- Fractures in other parts of the ankle (like the talar body or head)
- Rotational fractures, where the ankle has been twisted
- Ankle fractures that have also caused the joint to be dislocated
- Simple dislocations, where there isn’t a fracture involved
- Fractures in the heel bone, which can be divided into tongue type and depression type
- Dislocation or fractures that also affect the subtalar joint (a joint in the foot)
Doctors rely heavily on CT scans to tell the difference between these conditions and make an accurate diagnosis.
What to expect with Talar Neck Fractures
Talar neck fractures, which often occur with high-energy incidents and cause serious soft tissue damage, generally have a poor prognosis. These injuries often happen alongside other damage, which complicates the case because talar neck fractures rarely occur in isolation. Additional injuries to the lower extremities and spine can also make the outcome worse.
An analysis of 70 patient cases showed an increase in the need for foot and ankle reconstructive surgery after the initial fixing of the fracture. The study also found that a poor patient response and postoperative complications tended to go together. If we don’t properly identify and fix displacement of the fracture fragments, outcomes can also be worse.
It’s important that patients are aware that residual foot pain is common even after surgery to treat talar neck fractures. In fact, within six years of surgery, 18.6% patients needed another operation to fuse the joints of the hindfoot to alleviate the pain.
Possible Complications When Diagnosed with Talar Neck Fractures
Talar neck fractures, or breaks in one of the bones in the foot, can lead to several complications. It’s important to note that the following statistics vary depending on the case and the individual.
- Some studies have shown that between 11% to 100% of these fractures result in osteonecrosis of the talus, which is essentially death of the bone due to a lack of blood supply.
- Posttraumatic arthritis, or joint inflammation following an injury, appears to be even more common. It affects between 30% and 90% of patients.
- Around 81% of posttraumatic arthritis cases involve the subtalar joint, which is a joint in the foot.
- Postoperative infections are a potential risk due to the high possibility of an open fracture or injury to the soft tissue. The reported rate of deep infection is around 21%.
- The bones not properly joining back together, known as nonunion, is relatively rare with rates under 5%.
- However, malunion, where the bone heals in an incorrect or misaligned position, occurs in 20% to 37% of fractures.
- Varus malunion, a specific type of deformity caused by poor bone alignment, is the most frequently reported outcome.
Recovery from Talar Neck Fractures
The recovery process after an injury to the neck of the talus (a bone in the foot) can vary based on the kind of injury and if surgery was performed. If there are strong reasons for not carrying out a surgery at the injury site, the condition can be managed without it. Nevertheless, it’s rare to find these injuries without any displacement or movement of the bone. Therefore, doctors usually run a detailed imaging test, like a CT scan, to decide if non-surgical treatment could work.
If non-operational treatment is the right choice, patients will need to keep off their foot and may need a cast or splint to keep the foot stable for around 6 to 8 weeks until the bone heals. However, most of these injuries involve bone displacement and require surgery for proper healing. Recovery after the surgery might need around 6 to 12 weeks of no weight-bearing and immobilization as well.
Depending on their health risks, some patients may also receive medicines to reduce the chance of blood clots forming in their veins. Once the period of no weight-bearing is over, patients typically need physical therapy for another 6 to 8 weeks to fully recuperate.
Preventing Talar Neck Fractures
Fractures in the talar neck, a part of the foot, make up about half of all talus bone breaks. These particular fractures come with a fairly high risk of two conditions: avascular necrosis, which is the death of bone tissue due to a lack of blood; and post-traumatic arthritis, which is a form of arthritis that can develop after an injury. Because of where they occur, the complexity of the surgery needed to fix them, and the specifics of the blood flow to that area, these fractures can lead to these risks.
Quick identification and treatment are essential when dealing with these type of foot injuries. These can include symptoms like pain, swelling, and bruising in the back of the foot. It’s crucial to immediately head to an emergency department if you experience these symptoms, especially if they’ve been caused by a strong force across the ankle while the foot is flexed upward.
In rare cases, when a talar neck fracture has not moved out of place, surgery may not be needed, and the fracture can be managed by keeping the foot still for 6 to 8 weeks. However, most of these fractures will have shifted and will require surgery. If a displaced or moved talar neck fracture is not properly diagnosed, it can lead to complications, such as osteonecrosis (bone tissue death), malunion (bone healing in a bad position), or nonunion (failure of the bone to heal). These possible issues could result in severe pain, loss of mobility, and permanent deformity.
