The term “shin splints” is commonly used to describe leg pain or aches, but it specifically refers to pain along the inner border of the tibia—the large bone of the leg. It usually occurs in novice or poorly-conditioned runners, and the main treatment is rest. The exact cause of shin splints is somewhat controversial because there are several different reasons for the pain to occur:
OVERUSE SYNDROME
Overuse of a muscle refers to stress or sprain of a muscle from too much exercise. The overuse syndrome can also be caused by wearing inadequate shoes or by running on hard or sloped surfaces. The basic postural problem producing this is pronation of the foot. Pronation is a medical term which means outward tilting of the foot. People with flat feet or dropped arches have pronated feet. Stretching the foot outward places increased pull on the muscles that run along the inner border of the ankle and under the arch. These muscles originate along the inner side of the tibia. The major muscle–the posterior tibial muscle–helps hold up the arch. As a result of pounding on the arch and, thus, constant tugging on the muscle, the muscle belly is stretched and even torn away from the bone. Pain and inflammation result.
The pain may initially occur after running. Persistent running with the injury will only aggravate it and produce pain during activity and later with normal walking.
Treatment consists of rest and application of ice to the leg. Telling a serious runner to rest is about as undesirable as suggesting that he purchase a bicycle, but, like it or not, rest is most important for healing to occur. The period of rest may vary, but usually two to three weeks are required.
Once a runner has recovered, attempts are made to prevent future injuries. Firm, well-constructed shoes with arch supports are recommended. The arch support helps tilt the foot inward and corrects the pronation. If the standard supports in the shoes are not sufficient—and they may not be for excessively pronated feet—custom-made inserts or orthotics should be obtained. I usually recommend first trying less expensive standard inserts which can be purchased in any running store. Changes in running environment from hard to softer surfaces, such as a track, and away from uneven ground, will also help.
Also, I see many patients who have one leg that is around a ½ inch shorter than the other. It is a minor discrepancy and frequently, we do not know why this occurred. However, it can cause problems with the back, knees, or ankles. And it can also cause shin splints. The treatment is simple—a shoe lift or insert for the shorter leg.
TIBIAL STRESS FRACTURE
Another cause of leg pain is a stress fracture of the tibia. This is a small crack or hairline fracture of the bone. It occurs from the pressure of constant pounding. Localized pain results. The fracture may not become evident on x-rays for several weeks and sometimes a bone scan is necessary to make the diagnosis. The treatment is absolute rest from running until the fracture heals. A cast is sometimes required, but in some instances, protection with crutches is sufficient.
COMPARTMENT SYNDROME
A third –and rare reason — for shin splints is a “compartment syndrome.” Muscles are covered under the skin by a tissue called fascia. An analogy is the encasement of a sausage. Muscles enlarge when they are exercised, and in the leg, muscle expansion produces increased pressure in the compartment. The muscles become too tight under the skin and swelling results. The nerves and blood vessels adjacent to the muscles also become crowded and pinched, producing discomfort. Treatment consists of rest and ankle exercises, but in severe cases, surgery may be necessary to slit the fascial covering of the compartment and relieve pressure on the muscles. The surgery is fairly simple and usually effective.
To conclude, proper conditioning is important because shin splints frequently occur during training or in individuals who are unfit. Thus, increases in exercise and activities should be gradual. Proper shoes and orthotics may prevent overuse syndromes, but they will have little effect on stress fractures or compartment syndrome. And, finally, the importance of rest cannot be overemphasized.
Please note: these articles are for general information. They are not intended to serve as medical advice or treatment for a specific problem. Diagnosis and treatment of a problem can only be accomplished in person by a qualified physician.