A stress fracture is a small crack in a bone or severe bruising within a bone. In the feet, stress fracture usually occur in the second, third or fourth metatarsals, which are thinner (and often longer) than the adjacent first metatarsal.
Many stress fractures are overuse injuries. They occur over time when repetitive forces result in microscopic damage to the bone. The repetitive force that causes a stress fracture is not great enough to cause an acute fracture, such as a broken ankle caused by a fall. Overuse stress fractures occur when an athletic movement is repeated so often; weight-bearing bones and supporting muscles do not have enough time to heal between exercise sessions.
The most common cause of stress fractures is a sudden increase in physical activity. This increase can be in the frequency of activity, such as exercising more days per week. It can also be in the duration or intensity of activity, such as running longer distances.
Even for the nonathlete, a sudden increase in activity can cause a stress fracture. For example, if you walk infrequently on a day-to-day basis but end up walking excessively (or on uneven surfaces) while on a vacation, you might experience a stress fracture. A new style of shoes can lessen your foot’s ability to absorb repetitive forces and result in a stress fracture. Several other factors from your training regimen to your diet can increase your risk for a stress fracture.
Pain that diminishes during rest
Pain that occurs and intensifies during normal, daily activities
Swelling on the top of the foot or on the outside of the ankle
Tenderness to touch at the site of the fracture
Since stress fractures most often occur as a result of overuse, the first treatment includes stopping the activity that brought on the fracture. A period of rest is needed. Taking time away from the activity may be needed for six to eight weeks. Usually exercise can continue, but a low-impact form of exercise such as swimming, elliptical trainer or exercise bike is recommended.
Additional measures such as shoewear modification may be prescribed. A stiff shoe insert or bootwalker can be part of the treatment. And in certain cases, your doctor my recommend a cast or crutches. Calcium and vitamin D supplements often are prescribed.
Most stress fractures will heal with the conservative measures outlined above, but there are instances when surgery is needed. The most common situation that requires surgery is when the bone fails to heal, which is called a nonunion. Surgery would usually include placing screws to secure the bone. Sometimes this surgery also includes placing fresh bone into the area that is slow to heal. This process is called bone grafting.