Many of us are familiar with bone fractures caused by trauma, such as a simple or compound fracture of the leg. However, there is another form of bone damage which rarely appears on an x-ray, but can still be extremely painful and debilitating. Because it is caused primarily by excessive and cumulative stress on the bone, this form of injury is commonly called a stress fracture. Athletes, dancers and soldiers are especially susceptible, since their job descriptions include excessive standing, marching and running. Some sources even refer to this type of fracture as a fatigue or marching fracture.
Although any bone can potentially receive a stress fracture, most cases requiring treatment occur in the lower legs and feet. Whenever a person runs, dances or performs any other stressful movement, the shock must be absorbed by the body. Ideally, leg muscles should absorb much of the impact before it is transferred to the tibia (lower leg) or the metatarsal bones (feet). As the muscle becomes tired, however, more and more shock is absorbed directly by the bones. Over time this constant pressure and shock can cause a crack in the bone itself, even if it doesn't cause a complete break. This crack is considered a stress fracture.
Since a stress fracture rarely appears on a standard x-ray, other scanning methods are usually recommended, such as a CT scan or MRI. For many sufferers, the only hint of such a fracture is extreme pain in the affected area. Some minor stress fractures will eventually heal as the bone works to repair itself, so a few weeks of rest and some over-the-counter analgesics for pain should be enough. Other forms are more severe and may call for a plaster or air cast for support and protection. The patient is often asked to remain off the affected limb for several months.
A stress fracture can be prevented through modification of a training program or a change in technique or body mechanics. Runners should periodically change shoes to maintain proper shock absorption. Dietary supplements such as calcium and vitamin D should be used to increase bone density and strength. Some athletes and dancers find that a gradual increase in exercise can reduce the chances of developing a stress fracture. As the bones adjust to the controlled increases in shock, they become stronger and less likely to crack under unusual pressure.