A high ankle sprain is used to describe a particular type of ankle ligament injury. Normally, when someone sustains a sprained ankle, the ligaments that surround the ankle joint are torn. These injuries commonly cause pain and swelling around the ankle.
A high ankle sprain occurs when there is an injury to the large ligament above the ankle that joins together the two bones of the lower leg. These two bones, the tibia (shin bone) and fibula, run from the knee down to the ankle. They are joined together by this ligament called the "syndesmosis" or "sydesmotic ligament."
Symptoms of a High Ankle Sprain
A high ankle sprain causes symptoms similar to other ankle sprains, but patients often complain of pain when the ankle is externally rotated (turned to the outside) or when the calf is squeezed. This later finding, the so-called "squeeze test," is the classic test for syndesmotic injuries, but it is not very reliable for to make the diagnosis.
When a syndesmotic injury is suspected, your doctor can obtain special x-ray studies of the ankle called stress views. The ankle may look normal on routine x-rays even with a syndesmotic injury, but when the ligament is stressed, there may be abnormal alignment of the ankle joint depending on the severity of the injury. Tests such as a CT scan or MRI can also be used to assess a high ankle sprain, although they are not routinely needed.
Treatment of a High Ankle Sprain
Syndesmotic injuries tend not to heal as well as more common ankle sprains, that is why trainers and coaches of athletes are often concerned about high ankle sprains. Your doctor will first determine if the injury is stable or unstable. If the injury is stable (meaning the ankle joint is functioning normally), then the high ankle sprain can be treated in a cast, usually for a period of 6 weeks.
If the injury is unstable, then a surgery may be needed to stabilize the ankle joint. Your surgeon will typically place one or two screws between the tibia and fibula to hold the bones in proper position while the syndesmotic ligament heals. The are several methods of fixation of syndesmotic injuries, all with potential risks and benefits.
Because the syndesmosis is a ligament, it should be able to move small amounts. After healing of the ligament has occurred, some surgeons will remove the screws so the bones can move normally again. Other surgeons recommend leaving the screws in place, however they do often break as a result of repetitive stress. You can discuss with your surgeon the consideration of screw removal.
Zalavras C and Thordarson D. "Ankle Syndesmotic Injury" J Am Acad Orthop Surg June 2007 ; 15:330-339.