Stress Fracture Overview

A stress fracture is generally the result of overuse or repeated trauma to a bone. Also known as "fatigue fractures," stress fractures may occur when muscles become fatigued or overloaded and transfer the stress they cannot absorb to the nearby bone.

Bones are continually being remodeled (old tissue is broken down, and new tissue forms) in response to activities. If a bone breaks down faster than it is rebuilt, it can develop an area of weakness. Repetitive stress or overuse of that area may lead to a crack in the bone or stress fracture. The most common areas for stress fractures are the foot and lower leg.

Stress fractures in the bones of the foot are usually caused by overtraining or overuse. They can also be caused by repeated pounding or impact on a hard surface, such as running or jumping on concrete. Increasing the time, type or intensity of exercise too rapidly is another common cause of stress fractures to the feet and lower leg. Running in old, worn out shoes can also lead to stress fractures.

Women seem to be at greater risk of foot stress fractures than men. This may be related to a condition called relative energy deficiency in sport (RED-S) which is a combination of poor nutrition, eating disorders, and amenorrhea (infrequent menstrual cycle), that predispose women to early osteoporosis (thinning of the bones). The result of this type of decreased bone density is an increase in the risk of stress fractures.

High-impact sports such as running, gymnastics, and volleyball can increase the risk of stress fractures. In all of these sports, the repetitive stress of the foot strike on a hard surface causes trauma and muscle fatigue. Without the right shoes, good muscle strength or adequate rest between workouts, an athlete can develop a stress fracture.

Risk Factors

Researchers have identified several factors that may predispose athletes to multiple stress fractures of the lower extremities. These factors include the following:

• A high longitudinal arch of the foot.
• Leg-length inequality.
• Excessive forefoot varus (inward turning).
• Amenorrhea or menstrual irregularities in female athletes.
• High weekly training mileage in runners.

Diagnosis

Stress fractures may be difficult to diagnose because the symptoms are often vague and slow to appear. A generalized ache or tenderness over the bone in the area of the stress fracture may initially be diagnosed as muscle injury or muscle strain. Stress fractures of the tibia (shin bone) are often misdiagnosed as shin splints in the early stages.

In order to diagnose a stress fracture, a physician will perform a complete history and physical examination. It's important for athletes to explain their training history, including the type of exercise, as well as how much and how often they train.

X-rays are usually done, but often, a stress fracture will not show until pain has been present for about four weeks, and some stress fractures do not ever show on X-rays. Magnetic resonance imaging (MRI) will show a stress fracture.

A bone scan could also be ordered instead of an MRI, but MRI is usually preferred. Some people will opt to try treatment and not get an MRI for a definitive diagnosis. This should be discussed between the person and the clinician.

Stress Fracture Treatment

The best treatment for a stress fracture is rest. Taking a break from a high-impact exercise routine, such as running, and doing some low impact exercise, such as cycling or swimming, for several weeks can help the fractured bone heal. If an athlete pushes through pain and trains with a stress fracture, the fracture can enlarge or become a chronic injury that may never heal properly.

Sometimes, crutches or a walking boot will be recommended. Discuss with your clinician what types of exercise are OK to do. When the stress fracture is healed, you will need to return to high-impact activities gradually.

After rest, the typical stress fracture treatment recommendations include:

• Ice the injury.
• Replace worn out shoes.
• Return to sports gradually.
• Perform rehab exercises.

Other evaluations and tests may be done depending on history and risk factors (blood test for vitamin D, running gait analysis through a physical therapist, consultation with a sports dietitian, bone density test, etc).

Preventing Stress Fractures

The following advice may protect you from developing stress fractures in the first place:

• Follow the 10 Percent Rule. Progress slowly in any sport and gradually. Increase time or intensity (not both) by no more than 10% per week.
• Eat enough to support the exercise that you are doing as well as to support the other activities in your life. If you are unsure what your nutritional needs are, meet a sports dietitian. Make sure you are meeting your recommended daily allowances of calcium and vitamin D.
• Wear proper foot wear and replace shoes when needed.
• If pain or swelling begins and does not improve with gently warming up or worsens, stop the activity and rest for a few days.
• If pain persists despite rest, worsens or resolves with rest but returns with activity, see a healthcare provider.

Any foot pain that continues for more than one week should be seen by a doctor for a thorough evaluation and diagnosis.