ANKLE SYNDESMOSIS INJURY/ HIGH ANKLE SPRAIN

Although not as common as a traditional ankle sprain, the high ankle sprain or syndesmosis injury is often more severe and has a longer recovery time. To go a little more in depth firstly let's take a look at the anatomy and the mechanisms of a typical ankle sprain.

The Anterior Talofibular ligament (ATFL) sprain is the most common injury that people sustain to the ankle. This occurs when someone inverts (twists inwards) their ankle forcefully causing stress on the outside aspect of the ankle. 

The Deltoid ligament complex is located on the inside of the ankle and due to the shape of the ankle joint and common mechanism of injury stressing the lateral ankle it occurs a lot less. When someone everts (twists outwards) their ankle this causes stress to the deltoid ligament complex.

Moving higher up onto the lower limb to the Tibia & Fibula we have ligaments called the Anterior Inferior Tibiofibular ligament (AITFL) & Posteroinferior Tibiofibular Ligament (PITFL) these ligaments prevent separation of the tibia and fibula at the ankle joint. There is also another ligament like structure located in between the fibula & tibia called the interosseous membrane. It is a disruption to these ligaments (AITFL, PITFL) that is referred to as a high ankle sprain or syndesmosis injury. This will usually occur with either an inversion/eversion and an external rotational aspect to the movement and usually involves higher forces applied to the ankle joint. As a result of this injury the ankle joint is often unstable, with disruption of the tibia and fibula that makes up the superior (top) part of the ankle joint.

Mechanism of injury

In most cases, there is an external rotation of the foot involved. This is often seen in field sports where there is a quick and forceful change of direction with the foot planted on the ground. Or when we look at movements like landing from a jump or impact at the knee that causes the foot to move forcefully upwards and twist outwards (dorsiflexion & external rotation).

Diagnosis

Often with a syndesmosis injury, there tends to be less swelling and it can mask as being something less in severity. Things to look out for are pain higher up in the ankle, shin or knee, pain with lunging, pain on palpation over the AITFL and pain with dorsiflexion and external rotation test. Additionally, you should be wary of a syndesmosis injury if an ankle injury is not progressing and pain does not settle even weeks after the trauma. 

On assessment, once a syndesmosis injury is suspected it is important to attain further imaging to confirm the diagnosis. Once an MRI is attained and confirms a syndesmosis injury, management is either conservative or surgical. This depends on the severity of the syndesmosis injury, the damage to the surrounding structures and the stability within the joint. 

How long does it take? 

If appropriate to be managed conservatively (without surgery) this injury will usually take 6 to 12 weeks to heal but the rehabilitation journey is often longer to ensure a safe return to sport.

If managed with surgery it is usually about 6 weeks post surgery for healing time and then progressing to the normal rehabilitation process. This will be addressing swelling, range of motion, strength, balance & proprioception and a safe return to sport. This will typically take a further 6 to 12 weeks.

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