Snowboarder’s Ankle – A Commonly Mis-diagnosed Injury

A lateral talar process fracture is 15x more common in snowboarders compared with any other ankle injury. It occurs in a hard-to-spot location, often being missed on plain ankle X-ray and is therefore commonly mis-diagnosed as a simple ankle sprain.

The lateral talar process can be fractured by compressive forces, such as when landing hard from a jump on a dorsiflexed and everted ankle (ankle and foot pressed up and outwards) or from landing on the ankle with the foot twisted into inversion whereby the tough lateral talocalcaneal ligament pulls-off the lateral talar process.

Snowboarder’s fractures require a significant amount of force to be put through the ankle during the injury and therefore are more common in intermediate and advanced snowboarders, travelling at higher speeds.

Snowboarders are vulnerable to this fracture as their feet are bound to a hard board within boots that, relative to ski-boots are fairly soft. Additionally, the feet are positioned cross-wise relative to the direction of travel of the snowboard, meaning the subtalar joint, with motion that is limited in comparison to the ankle joint, has to absorb the majority of changes in ground-force.

Between 30 and 40% of Snowboarder’s fractures are mis-diagnosed as an ankle sprain as the external signs are very similar- severe lateral ankle tenderness, swelling and bruising. Obvious fractures, usually of significant size and with a fracture-gap, can be seen on plain X-ray but many can be missed due to the discrete fracture location.

Most often, cross-sectional imaging, preferably CT scanning or else MRI is used to confirm the injury and allow analysis of the fracture characteristics that determine treatment- such as fragment size, displacement and involvement of the subtalar joint beneath the fracture.

If the fractured lateral talar process is large enough to hold screws and is in only one or two pieces it is usual to surgically-fix the fracture to enhance the chances of bone union and allow early hindfoot joint motion to reduce stiffness. Ideally, any fracture extending into the subtalar joint should be fixed with surgery, especially if there is a large step in the joint or a large fracture gap. This is done to reduce the chances of subtalar joint arthritis. With more than two pieces of bone (comminuted fractures) or very tiny fracture fragments it is more common to treat with a period of cast immobilization followed by physiotherapy. It is important the injury is managed by an experienced orthopaedic foot and ankle surgeon.

Lee operated on this 29 year old snowboarder who sustained a Snowboarder’s fracture in France.

The CT scan before fixation permits visualization of the injury in multiple anatomical planes and in this case shows the fracture extending into the patient’s subtalar joint with a significant gap between the lateral talar process (arrow) and the main body of the talus.

The patient was treated with surgery (Open Reduction and Internal Fixation) to restore the precise alignment of the subtalar joint surface and the integrity of the hindfoot ligaments that take their bony origin from the lateral talar process. The patient’s post-operative X-rays at 6 months are shown. At this stage he had returned to running and keenly awaits the start of the post-Covid winter-sports season!

Ultimately, awareness of the conditions liable to cause you injury is key to avoiding a Snowboarder’s ankle. Terrain and speed awareness are important as well as not exceeding your skill limitations. This applies to the Piste as well as the Snowpark. Instruction from an experienced snowboarder can be invaluable.

There are however specific factors which you can address, well before setting off for the Piste:

• Having a degree of inherent ankle stability will be beneficial and incorporating some exercise drills using wobbleboards and specific strengthening of the peroneal muscles, whose tendons cross the outside of the ankle and provide additional stability can be helpful.
• Ultimately, your kit has to be fit for purpose and making sure you have well-fitting boots and bindings is crucial in avoiding injury.
• In rare cases a bespoke insole or even an ankle brace if there is a perceived vulnerability to injury, can be very helpful.

Mr Toby Baring, Shoulder and Elbow Surgeon at OneWelbeck Orthopaedics explains how to minimise ankle injuries during skiing.

Mr Lee Parker is a Consultant Foot and Ankle Surgeon at OneWelbeck Orthopaedics. A well-known figure within his specialty, Mr Parker has extensive experience in managing foot and ankle trauma. His NHS base is at The Royal London Hospital, one of Europe’s largest trauma centres. 

If you have any concerns about ankle injuries don’t hesitate to get in touch with OneWelbeck Orthopaedics – you can either call us on 020 3653 2002, or email us at bookings.orthopaedics@onewelbeck.com.