Shin Splints

Shin splints (medial tibial stress syndrome) is an overuse injury caused by small tears in the lower leg muscles. Shin splints occur along or just behind the inner (medial) edge of the shin (tibia). The pain usually involves a span measuring about 3 inches to 4 inches. The pain recurs if you try to run before healing is established. Studies show that medial tibial stress syndrome (MTSS) commonly affects runners. As many as 13.2 to 17.3 percent of all running injuries have been attributed to MTSS. Shin splints are among the five most common running injuries

Shin splints are an inflammation of the thin layer of tissue that covers the bone (periosteum). The bone tissue itself is also involved. This can be seen on bone scan examinations. The muscles that attach to the shinbone through the periosteum are the part of the shin that hurts. These are the soleus muscle (an ankle flexor important in pushing off the foot) and the deeper of the two toe flexors (flexor digitorum longus).

Risk Factors/Prevention - Certain factors seem to contribute to the onset of MTSS. Circumstances can result in abnormal tension at the site of the bony attachment. The tension causes microscopic tissue injury. Running can cause tissue damage that must heal and adapt to the increased level of tension. When training causes damage more quickly than the area can heal, a more chronic inflammatory state seems to occur. Some factors can help cause tension and microdamage more quickly than the area can heal and adapt.

You may be more likely to get MTSS if there are abnormal stresses from:

• Flatfoot or abnormally rigid arch (foot/ankle mal-alignment)
• Knock knee or bow legs (knee mal-alignment).

Circumstances that contribute to MTSS include relatively sudden changes in -

• Training regimens, such as running longer distances or on hills, increasing the length of time spent running or increasing the number of days you run each week
• Surfaces, such as running on concrete
• Wearing shoes that have lost their shock absorbing capacity can also be a factor.

What are the symptoms?

Symptoms of shin splints include pain during increased activity. The pain is felt along or just behind the inner edge of the shin. It measures a distance of several inches. It is centered about two-thirds of the way down from the knee. See your doctor to diagnose MTSS. Tell him or her your complete medical history and describe how the condition started. The doctor will examine you and recommend treatment.

What are the treatment options?

Treatment for shin splints involves several weeks of rest from running. You may cross-train. The doctor may recommend that you take anti-inflammatory medications, or use cold packs and mild compression to feel better. Most often the pain is not so bad with just ordinary walking. After several weeks of rest, training begins at a level much lower than what you were doing before. Increase training slowly. If you start to feel the same pain, quit exercising immediately for the rest of the day. Use a cold pack and rest for a day or two. Return to training again at a lower level of intensity. Increase training even more slowly than before.

Returning to training after suffering from shin splints?

Use pain as your guide:

• Severe pain is avoided.
• Mild pain is a sign you have reached or even passed your maximum level for the session.
• Most people eventually get back to their prior level of fitness/training.

Treatment Options - Very few people need surgery for MTSS. For severe MTSS that does not respond to the usual treatment, surgery has been described. It is not clear how effective it is.

The accuracy of the diagnosis is a concern. When shin splints are not responsive to treatment or there is great time pressure to return to conditioning, a bone scan and MRI (magnetic resonance imaging) can often show if there is a stress fracture. MRI can also help the doctor diagnose tendonitis, especially if there is a partial tear of the involved tendon. An uncommon condition called chronic exertional compartment syndrome involves swelling of muscle with exertion. This happens within the muscle's usually tight compartment in the leg. These compartments are non-yielding. Swelling can raise pressure within the compartment to levels so high that blood will not flow into the muscle. This causes severe pain and is best treated surgically. Diagnostic tests required for chronic exertional compartment syndrome are highly specialized, and not easily available. They involve pressure measurements within the compartments immediately after exercise.

The diagnostic tests, causes of shin splints, and treatment regimens all bear a similarity and relationship to stress fractures. It is possible that there is a relationship between MTSS and stress fracture at the tissue level, but this has not been clearly identified.