High Ankle Sprain (syndesmosis injury)
A syndesmosis injury mainly occurs with ankle fractures (in 13%) but is also injured in 0.5% of all ankle injuries without a fracture. The mechanism of injury is most commonly external rotation. Syndesmosis injuries are associated with injuries to the articular cartilage (up to 25%) and to the peroneal tendons (up to 25%). If the injury is missed it may result in ankle arthritis. Early diagnosis and treatment is therefore crucial. The typical symptoms are pain or difficulty with weight-bearing, anterolateral pain and pain with passive external rotation. Xrays are not always helpful and often a CT scan is indicated for diagnosis especially with chronic injuries. With acute injuries conservative treatment is indicated for sprains and partial tears with ankle instability. A walking CAM boot for 2-3 weeks and delayed weight-bearing until pain free is the treatment of choice. Most often surgical treatment is indicated as the fibula trends to displace posteriorly. Open reduction and temporary fixation either with screws or plate and screws or suture button fixation.
Low Ankle Sprains
Ankle sprains are common and the main reason for loss of training. Articular cartilage and peroneal tendon injuries are also common in low ankle sprains. The ATFL is the most common ligament injured followed by the CFL. Injuries can be divided into different grades. 
In grade 1 the ligament is intact with minimal swelling and no pain with weight-bearing. In grade 2 the ligament is stretched without a tear and moderate swelling; weight-bearing is possible but painful. With grade 3 injuries there is a complete tear, severe swelling and difficulty weight-bearing. Early treatment for all grades include RICE, compression and physical therapy. Severe pain may require a CAM boot or ankle brace. Immobilisation should not exceed one week. Ongoing instability may require surgical repair. In general grade 1 and 2 injuries can return to athletic activity after 1-2 weeks; with grade 3 it may take several weeks.