Going over on an ankle can lead to many different injuries, including broken bones. The ankle joint is made up of three bones: the tibia, fibula and talus. These bones fit together to give up/down as well as side-to-side motion. A typical ankle injury involves the body going over towards the outside of the ankle. This movement is called inversion of the ankle. Broken bones as a result of inversion injuries are relatively rare when compared to ligament injuries.
The ligaments on the outside half of the ankle, again as shown in the diagram, limit the amount of inversion that the ankle would normally go through in usual movements. When these ligaments are stretched or torn, the ankle may become somewhat unstable. This could lead to recurrent injuries.
Ligament sprains or tears are graded as follows:
Grade 1 - Minor stretching or tearing of the ligaments
Grade 2 - A significant tear of at least one or more of the ligaments
Grade 3 - A full tear of all of the ligaments.
Grade 1 and 2 tears can be treated conservatively, with the usual regimen of RICE:
R - rest
I - ice (15 minutes three to four times a day)
C - compression (with a tensor bandage)
E - elevation
Grade 3 tears should be treated with some kind of immobilization for several weeks. We used to cast the ankle for six weeks, or perform surgery to repair ligaments torn like this. Some studies have shown that using a removable splint which allows for up/down motion of the ankle does just as good a job of helping the ligaments heal, without the risks of surgery, or without as big a risk of possible permanent stiffness of the ankle as with a full cast.
There are nerves that run along with the ligaments on the outside half of the ankle. These are the nerves that tell your brain whether your ankle is level or tilted. When you stretch the ligaments, you also stretch the nerves. After an ankle injury, without retraining the nerves to function properly, the next time you step into a hole or land awkwardly, the brain doesn't get the signal from the ankle to level the ankle immediately, and you may end up spraining the ankle again. This is one of the most important reasons to do physiotherapy on a sprained ankle, and why when people don't do the proper rehab, they may end up having recurrent injuries. This lack of balance is also the main reason why even players having mild or grade 1 sprains are at risk of more significant injury if they return to play immediately. That's not to say that anybody with a sprained ankle should sit out the rest of the game, but it does mean that the player returning to the field after such an injury should understand there is an increased risk for another injury.
So when should you go to the doctor after an ankle sprain?
If you can't put any weight at all on that leg even after several minutes, there is the possibility that a bone is broken. You should see a doctor as soon as possible.
If there is immediate and significant swelling, but you are able to bear weight, there may be a bad enough sprain or tear of the ligaments that a cast or other treatment may be necessary. You could see a doctor as soon as is practical.
If this is your first ankle sprain, it might be worthwhile to have it assessed, and to enroll in a program of physiotherapy, more so for education on prevention of further injuries than anything else.
Preventing ankle injuries in the first place involves a number of different factors. Such factors as good field quality, good visibility and most importantly good sportsmanship are critical. Personal factors, such as good flexibility, strength, balance and situational awareness are equally important.