sprains and strains

A sprain is the most common ankle injury. While most sprains are mild, ankle sprain is a potentially serious injury with possible long term complications. Sprains may range in severity of injury from minor damage to the ligaments¹ to complete tearing off of the bony attachment (a so-called avulsion fracture), and dislocation of the joint.

A strain is a more minor type of injury that does not involve loss of joint stability or tearing of ligaments, whereas a sprain does.

A sprain occurs when stress is applied while the ankle is in an unstable position, causing the ligaments to overstretch or tear.

Ankles are usually sprained when the foot is flexed downward while walking or running over an uneven surface. This is the least stable position of the ankle, in which it is most susceptible to twisting forces rolling the foot inward or outward.

Sprains are classified by degrees:

first-degree, involving stretching of ligamentous fibers
second-degree, involving a tear of some portion of the ligament with associated pain and swelling
third-degree, complete separation of the ligament

Inversion injuries are most common. Inversion means the foot rolls such that the sole turns inward (version: Latin term for "turning"). A snap or tear may be heard or felt when the injury occurs. This injury naturally damages the ligaments on the outer side (lateral) of the ankle. Fluid accumulation or swelling (edema) around the injured ligament is common. Immediate swelling after a sprain means bleeding around the ligament, and implies a more significant tear.

True sprains of the ankle always produce some degree of instability of the ankle joint. Complete diagnosis of the severity of a sprain may require re-examination several days after the initial injury, when the pain and swelling have subsided enough to allow the doctor to examine the joint properly.

Treatment of sprains

First priority is control of swelling. Swelling and bleeding further stretch the ligaments of the joint and can lead to further late complications.

An elastic bandage, ice water, and elevation are often helpful in controlling swelling. The ankle should be placed in ice water for 15 to 20 minutes and then elevated (an ice pack can substitute for ice water).
Strains and mildly to moderately severe sprains are managed by repeated ice packs, followed after 48 hours by hot soaks.
The ankle is splinted or taped for one to two weeks to maintain stability during healing. The inflatable cushion Air Cast® is often very helpful for this.
Partial weight bearing is accomplished by using a crutch until pain subsides.
Non-weight-bearing exercises are started within 2 to 3 days of injury. These include having the patient flex the foot down and up, and rolling it from side to side (pointing the sole of the foot toward and away from the body (inversion and eversion).
After the pain subsides and the swelling resolves, full weight bearing can be resumed. A plastic "sprain brace" may be used to maintain stability of the ankle from side to side while allowing normal up and down flexion of the foot.
Running should be delayed for another 1 to 3 weeks after the pain and swelling are gone. The length of time out from running is determined by the severity of the sprain.

Small avulsion fractures² of the leg bones are not uncommon with severe sprain. In this case, the doctor can often suspect this even before xray studies, because the patient is usually very "point tender" right over the fracture. For severe sprains casting for several weeks or even surgical repair of torn ligaments may be necessary.

¹ligament A tough, fibrous band of tissue connecting two bones for stability and strength.
²avulsion When a piece of tissue or bone is torn forcibly away from its proper position, as in an avulsion fracture.

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