What is a stress fracture?

A stress fracture is a small break in the bone. In a stress fracture, a thin crack develops from repetitive force, which is usually caused by overuse. Most stress fractures occur in the bones of the foot and lower leg, which carry the weight of the body.

The most common locations of stress fractures are the second and third metatarsals of the foot. Stress fractures are also common in the heel, in the outer bone of the lower leg, and in the navicular (a bone in the top of the foot). (See illustration.)

The bones of the foot

Stress fractures make up 2% of all sports injuries in athletes.

What are the symptoms of a stress fracture?

The symptoms of a stress fracture include the following:

  • Minor pain and/or weakness in the area where the break is located.
  • Pain deep within the foot, ankle, or toe.
  • “Pinpoint pain” (tenderness at the site of the fracture when it is touched).
  • Swelling on top of the foot or in the ankle.
  • Pain that occurs during or after normal activity.
  • Pain that is brought on by activity and relieved by rest.

If the stress fracture is not treated, the pain can become severe. The fracture can also become displaced (the fractured bone moves out of normal alignment)

What causes a stress fracture?

When bones are involved in a new activity that can cause stress, such as a new exercise routine, they may have trouble adjusting. This can cause them to crack.

Other causes of stress fractures include the following:

  • Muscles become tired from repeated impact and transfer the impact to the bone.
  • Change in activities; for example, an increase in exercise and athletics, or different job duties without a gradual break-in period.
  • Errors in training or technique.
  • Changes in surface; for instance, going from a soft surface (an indoor running track) to a harder surface (sidewalk or street).
  • Repetitive activity in certain high-impact sports, such as long-distance running, basketball, tennis, track and field, gymnastics, and dance.
  • Improper footwear (shoes that are too worn out, too flimsy, or too stiff).
  • Foot problems, such as bunions, blisters, or tendonitis, that can affect the way the foot strikes the ground.
  • Osteoporosis or other diseases that weaken bone strength and density (thickness). The weak or soft bones may not be able to handle the changes in activity. Female athletes who have irregular menstrual periods, or no periods, may also have lower bone density.
  • Low vitamin D levels.

What can happen if a stress fracture is not treated?

If a stress fracture is not properly treated, serious problems may develop. For example:

  • The fracture can get worse. Eventually, it can become a complete break if you do not change your activities. If the break does not receive professional medical attention, it can heal improperly and become a source of pain and disability.
  • The fracture can cause a defect in the bone that can limit the ability to move the foot, or make it difficult to find properly fitting shoes.
  • You can develop arthritis, which may be caused by fractures that extend into a joint (the juncture where two bones meet).