A syndesmosis ankle sprain is a tear of the syndesmotic ligament. This ligament joins the two lower leg bones together (tibia and fibula). Patients with this type of injury often have pain when the ankle is externally rotated (turned to the outside) or when the calf is squeezed. In fact, the "squeeze test" is often used to make the diagnosis.
There are special X-ray studies of the ankle that can be done to confirm this diagnosis. The radiologist takes "stress views." Abnormal motion between the bones with these X-rays
is a telltale sign of a syndesmosis ankle sprain.
This type of injury does present the way you describe your ankle. Walking or skating in a straight line isn't a problem. Any movement that requires external rotation of the ankle and lower leg causes pain and/or stiffness. It takes most players four to eight weeks to get back to full play.