A high ankle sprain is a foot and ankle injury to the ligaments located above the ankle joint and responsible for holding the lower leg bones (tibia and fibula) together.
Taken together with the membrane running down the length of the tibia and fibula, and also helping to hold those bones together, these bones and ligaments form what is known as the syndesmosis joint. As a result, high ankle sprains are also referred to as syndesmosis injuries or syndesmotic ankle sprains.
These sprains tend to affect athletes in sports like football, soccer and basketball who have to do a lot of running interspersed with twisting or turning movements.
High ankle sprains cause pain that radiates up your leg and is mainly felt above ankle level (unlike regular ankle sprains).
Unless they are accompanied by bone fractures (discussed further below) they are treatable by the same Protection,.Rest,.Icing, Compression and Elevation strategy commonly used for regular ankle sprains. However, the recovery time for high ankle sprains is usually somewhat longer than that for regular ankle sprains.
In general, unlike regular ankle sprains, syndesmotic injuries cannot be treated or prevented by the use of an ankle brace.
Lower Leg Anatomy & Causes Of A High Ankle Sprain
The two lower leg bones that are involved in high ankle sprains are the tibia and fibula. The tibia is the bone commonly referred to as the shin bone and is the larger of the two. The fibula runs to the outside of, and slightly behind, the tibia.
The two bones are connected by two ligaments:
The anterior inferior tibiofibular ligament (AITFL), which runs in front of the two bones. This is the ligament that is usually injured in cases of regular ankle sprains, with the damage occurring lower down and on the outside of the ankle;
The posterior inferior tibiofibular ligament (PITFL) , which crosses behind the tibia and fibula.
In addition to these ligaments, there is a band of soft tissue that runs along the length of the two bones and also helps to hold them together. It is known as the interosseous membrane.
When we stand, run or walk, the tibia and fibula are subject to high forces that tend to spread them apart. This tendency is resisted by the two ligaments and the interosseous membrane whose role is to keep the bones from separating too much.
However, during intense running, especially when accompanied by twisting and turning, the AITFL and PITFL are subject to unusually high forces, greater even than the ones they regularly have to withstand. The twisting and turning requires the athlete to sharply rotate the ankle while running at high speed, and this increases the forces on the syndesmosis joint even further.
These conditions can therefore cause damage to the 2 ligaments that results in a high ankle sprain.
If the forces on the syndesmotic joint are high enough, the athlete may experience a fracture of the fibula in addition to ligamentous injury.This type of lower leg fracture is called a Maisonneuve fracture or Maisonneuve injury.
Unlike low (or regular) ankle sprains, high ankle sprains usually do not cause significant swelling or bruising. This means that it can be easy for the athlete to underestimate the seriousness of the injury until it has been examined by a doctor.
The signature symptom of a high ankle sprain is pain that starts just above the ankle and radiates up the leg. Typically, the athlete will feel this pain with each step that he or she takes.
In addition, the pain will usually intensify if the foot is twisted in the same direction as the movement that originally caused the injury. For example, if the athlete was injured when twisting the right foot outward (to execute a sharp right turn), then the same movement will likely cause intense pain until the injury is healed.
Activities that require foot flexion (pointing the toes upward) will also cause increased pain.For example, the athlete will feel additional pain when climbing stairs.
If there is an accompanying fracture, the pain will be so severe that any weight bearing will be impossible.
An athlete experiencing symptoms similar to those above should consult a doctor with sports medicine expertise as soon as possible.
In diagnosing the cause of the foot and ankle pain, your doctor will most likely conduct a thorough physical examination of the painful lower leg area. A key objective will be determining whether the pain is at ankle level (as for a normal ankle sprain) or above it.
The doctor will probably also check for tenderness over the deltoid ligament at the inside of the ankle. That would be a preliminary indication of the existence of a Maisonneuve fracture.
In addition to examining the injured foot and ankle, the doctor will probably ask the patient detailed questions about how the injury occurred.
There are two tests that are widely used in diagnosing a possible high ankle sprain:
The “squeeze test’, performed by squeezing the leg just below the knee. If the pain radiates down the leg towards the ankle, this is a possible indication of a syndesmosis injury;
The “external rotation” test, in which the patient bends the knee while keeping the ankle at a 90 degree angle in relation to the leg (i.e. in a neutral position). The doctor will then ask the patient to rotate the foot away from the center of the body. If this causes ankle pain, it points to a possible high ankle sprain.
A key part of diagnosing a possible syndesmosis injury will be an imaging scan of the lower leg and ankle. MRI or CT scans can help to determine whether the fibula and tibia appear to have an unusually wide space between them.
X ray imaging can also be used to reveal a fibula (or other bone) fracture.
Treating A High Ankle Sprain
If there is no evidence of a bone fracture or complete severing of the syndesmosis ligaments, doctors will likely opt for a home based treatment strategy similar to that used for mild or grade 2 ankle sprains:
The athlete will be advised to avoid putting weight on the injured leg. This will of course require a suspension of sporting activities. To keep weight off the leg entirely, the athlete may consider using crutches or a wheelchair;
A walking boot may be a useful option for protecting and resting the injured ligaments during recovery;
Apply Ice to the injured foot and leg for 15-20 minute period every 2-3 hours until the pain has receded. A cold compress may be used in lieu of ice;
Elevate the injured leg above heart level whenever possible, e.g. when lying or sitting down.
If there has been a fibula fracture, or if a syndesmotic ligament has been completely severed, these measures will not be adequate. Instead, an orthopedic surgeon will need to operate to bring the tibia and fibula together and hold them in the correct position (using screws or suturing) while recovery proceeds.
Whether treatment is home based or involves surgery, physical therapy will be an important part of the treatment. It will help to strengthen the ankle and lower leg tissues and restore the patient’s original range of motion.
As mentioned above, the athlete will need to spend a longer time off the field than with a regular ankle sprain before a return to sports can be considered. The total recovery time can range from 6 weeks for a mild injury to six months or more for a serious one.