The bones of the legs and feet are where stress fractures most frequently occur. The bones that are most often affected include the lower parts of the tibia and fibula bones of the leg and the second and third metatarsal bones of the foot. A stress fracture can develop after repeated excess pressure or loading on a bone. It differs from a typical broken bone caused by a sudden injury in that a stress fracture develops in response to chronic stress on the bone.
A stress fracture is sometimes referred to as a hairline fracture because it usually shows on an X-ray as a hairline crack. These types of bone fractures are often associated with running and other athletic activities, especially when there's been recent increase inactivity.
Stress fracture location is sometimes linked to a particular sport or activity. Runners have a higher than average risk of tibial stress fractures, and activities that involve a lot of stress on the forefoot, such as dancing or track and field,1 bring an increased risk of stress fractures of the metatarsals or navicular bone of the foot.
Symptoms and Diagnosis
Pain that is brought on or made worse with weight-bearing activity may indicate a stress fracture; pain may also be felt with direct pressure on the bone. If left untreated, the pain will usually worsen, and continued stress on the bone may cause a hairline fracture to develop into a more unstable fracture. This is why it's important to decrease weight-bearing activity and seek medical treatment when pain occurs.
A stress fracture that is developing may not always show up on an X-ray, which can make diagnosis difficult. It is not uncommon for initial X-rays of bone to show no fracture, while a follow-up X-ray—days or even weeks later—will reveal that a stress fracture has in fact occurred. Medical providers will often use other diagnostic methods if they suspect a stress fracture, such as a CT scan or MRI, even though X-rays were normal.
Treatment for a suspected or confirmed stress fracture will involve rest or a change in athletic activity that's sufficient enough to allow for healing. Immobilization in a walking cast or hard-soled shoe may be prescribed for a few weeks, depending on the degree of fracture and symptoms. Follow-up X-rays or other diagnostic tests are used to evaluate bone healing.
Stress fractures are most often associated with athletic activity, but other factors increase the risk as well. Any condition that causes a decreased bone mass will increase the risk of a stress fracture, including:
Post-menopausal women and women who have irregular menstrual cycles, resulting in amenorrhea2
Moderate to heavy alcohol use
Lower body mass
Medications such as corticosteroids and DMPA (Depo-Provera)
Inadequate levels of calcium and vitamin D3
Abnormalities of foot structure or foot biomechanics, such as a high-arched or flat foot