High Ankle Sprains
What is a high ankle sprain?
The high ankle ligaments are located above the ankle, as opposed to the more commonly injured ligaments on the outside of the ankle. The high ankle ligaments are called the anterior inferior tibiofibular (AITFL) and posterior inferior tibiofibular (PITFL) ligaments. These ligaments connect the two bones of the leg, the tibia and fibula, just above the ankle joint – this area is called the syndesmosis. It is critical to have stability between these two bones as they form the top and sides of the ankle joint and are subject to high forces when walking and running.
A high ankle sprain occurs when there is tearing and damage to these high ankle ligaments, which occurs much less commonly than a traditional ankle sprain.
Causes, signs and symptoms
High ankle sprains occur from rotational or twisting injuries, much like ankle fractures. They are common in sports, especially impact sports. An external rotation mechanism, when the foot is turned outwards with respect to the leg, most commonly causes these tears.
The high ankle ligaments can be torn in isolation, or with some types of ankle fractures as well. In some cases, the high ankle ligaments are ruptured along with the medial ankle ligament, the deltoid, plus a fracture at the top of the fibula bone near the knee. This type of injury is called a Maisonneuve injury. Patients with a high ankle sprain without a fracture can often bear weight, but complain of pain at the junction of the two leg bones just above the level of the ankle. This is higher than more traditional sprains.
Patients who have a high ankle ligament tear usually will have pain just above the level of the ankle. They may also have tenderness over the deltoid ligament and the lateral part of the lower knee if they have a Maisonneuve injury, as noted above. It is important to touch the area to assess whether pain is just around the lateral ankle ligaments or higher.
Two important examination tests are the “squeeze test” and the “external rotation test.” The squeeze test is performed by squeezing the leg at the midcalf level – if this causes pain just above the ankle joint then a high ankle sprain is likely. With the external rotation test, the knee is bent and the ankle is placed in a neutral position, and the foot is rotated outwards. If there is pain at the syndesmosis or the high ankle ligament area, then this also indicates injury.
X-rays are very important. A broken bone must be excluded. Three views of the ankle including the whole leg are needed. A fracture on the back portion of the tibia may indicate an injury to the high ankle ligaments given that this is where the PITFL attaches. It is also important to look for increased space between the tibia and the fibula because this may also indicate an injury to the high ankle ligaments – gapping between the bones is called a diastasis. MRI is becoming very helpful in diagnosing these injuries. A CT scan can also help to assess the relationship of the tibia with the fibula.
The primary goal of treatment is for the tibia and fibula to heal in their normal anatomical positions with respect to each other. It is very important to understand that these injuries take a lot longer than typical ankle sprains to heal.
Initial treatment for a sprain without a fracture is using the RICE principles - rest the leg, ice for 20 minutes every two to three hours, gently compress the leg with a tubigrip bandage, and elevate the leg with the foot above the level of your heart. You may have enough discomfort that a removable walking boot is recommended. If weightbearing is possible then aggressive physiotherapy is very important. This includes strengthening the stabilising tendons on the outside of the ankle called the peroneals.
It usually takes six weeks or more to return to sport, but can sometimes take even longer. One good indication that you are ready to go back to sports is if you can hop on the foot 15 times. This hopping test should only be done if there is no obvious widening between the tibia and the fibula on X-rays.
If there is widening (a diastasis), or if there is a broken bone, surgery is usually needed. Surgery involves internal fixation of fractures after putting them back in their normal positions, along with restoring the normal relationship of the tibia and fibula with screws or special suture material.
Recovery and rehabilitation
The recovery for high ankle sprains can take considerably longer than typical ankle sprains, and athletes usually take six to eight weeks to return to sport. In those cases in which a separation of the tibia and fibula or fracture has occurred and surgery is necessary, patients will likely need to be non-weightbearing in a cast or moon boot for 6 weeks. Early range of motion exercises with a physiotherapist are important to help avoid stiffness. Any screws that cross the two bones (diastasis screws) are commonly taken out in a small second procedure before returning to sport is allowed.
Outcomes are generally good if the injury is recognised and treated appropriately. Stiffness is more likely though after a high ankle sprain compared with a standard lateral ankle sprain. This is especially the case if the ankle was also broken.
Frequently Asked Questions
Should I be concerned if I have sprained my ankle and it is not better after six weeks?
Yes. Most ligaments will heal after six weeks. It is probably worth seeing your doctor to assess if any other injuries have occurred. Sometimes high ankle sprains can take six weeks or longer to heal, but it is wise to ensure that another injury has not occurred.
Can I tear both the high ankle ligaments and the low ankle ligaments?
It is rare to have such an injury since the force is generally transmitted through one area or the other. However, there are reported cases where both sets of ligaments have been damaged during the same injury.