You are running full speed, you plant your foot to cut left and spin around a defender…when you feel that pain on the outside of your ankle that stops you from taking another step.  Or, maybe you were walking across the room and tripped on the carpet.  Either way, you’ve sprained your ankle and…it hurts (but you already knew that!)  Keep in mind that swelling is not necessarily a good indicator of how badly your sprain is, so don’t focus too much on it.

There are two long bones in your lower leg, the tibia (main shin bone) and fibula (smaller bone alongside & to the outside of the tibia.)  Both bones flare out at the ankle, the tibia on the inside and fibula on the outside, and it’s these flares that are the bumps you see that most people refer to as their “ankle bones.”  The first bone below this dome-shaped opening is the talus.  This bone is the third bone that make up the ankle joint and it is slightly wider toward the front and more narrow toward the back.  As you bring your foot up toward your leg, the talus becomes wedged into the dome created by the tibia and fibula, creating a very stable position.  As you point your foot away from your leg, or downward, the ankle joint becomes looser and can move from side to side, relying less on bony stability and more on ligaments to keep it intact.

Ligaments (strong, rope-like bands of tissue that don’t stretch) connect the upper part of the ankle to the lower part.  On the inside, there is a strong, triangular-shaped ligament called the deltoid ligament.  It is far less common for this ligament to be injured because the bone on the outside goes down further and limits the outward motion that would sprain the deltoid ligament.  On the outside of the ankle there are three ligaments that fan out to the front, back and down, providing stability in a variety of directions. 

A sprain is merely a stretching of the ligament.  Typically, when the ligament stretches with minimal disruption or tearing of the fibers, then it is called a grade I sprain.  A slight tearing is a grade II and complete tearing is called a grade III sprain.  The mechanics of lateral (outside) ankle sprains are such that the front ligament almost always must tear first and then the middle, or downward angled ligament is next, followed by the backward facing ligament.  So, you could have a complete tear of the anterior talo-fibular ligament (the forward facing ligament) but rather than being a grade III sprain, it is usually called a grade I or II because the other two ligaments are still intact and providing two-thirds of the outside support.

Sprains cause swelling, pain and guarding, all of which lead to weakness and a decrease in balance.  Initial treatment is geared toward reducing swelling, getting the muscles to work again, allowing healing while preventing further damage and then gradually increasing weight bearing, strengthening and neuromuscular control (basically, how the muscles and nerves communicate and react to control movement and balance.)

Strengthening can start with resistance bands and move toward weight bearing exercises as the pain and swelling go away.  Re-training the neuromuscular control component focuses on balance activities which can progress from standing on the floor on one leg to adding movement and advancing to standing on an unstable surface (foam cushion or folded towel) and eventually (only for the higher level needs and only when supervised) to a moving surface (wobble board.)

Simple sprains with no instability can be advanced more quickly, based on pain.  More moderate and severe sprains need to take into consideration not only pain but also the healing constraints of the injured tissue.