What are Stress Fractures?

The term “stress fracture” often gets thrown around a lot in medicine, but sometimes it is poorly understood. In order to understand how a stress fracture occurs and what exactly it is, a little bit of information on how the bones form is necessary first.

A common misconception is that bones are dead. This is one-hundred percent false. Bones are in fact a complex organ system. They are a living tissue that is constantly remodeling itself. Some cells in the bones work to degrade the bone material, while others work to rebuild it. This constant turnover of bone material is extremely important in bone health, and defects of this system are the cause of disease like osteoporosis. It takes approximately seven years for a complete turnover of the human skeleton – if you are twenty one years old, your bones have gone through three complete cycles!

When the repetitive stresses of activities like walking and running outpace the bones’ ability to repair themselves, a stress fracture occurs. Stress fractures are extremely common in runners, where the forces on the body and the bones are increased greatly. Stress fractures account for roughly 10% of all running injuries, and 95% of all stress fractures occur in the lower extremity.

A common thought among podiatrists and other types of sports medicine doctors is that stress fractures are more likely to occur during muscle fatigue. The muscles play a large role in distributing body weight and forces throughout the body. When the muscles are fatigued, this distribution is lost and more force is placed directly on the bones. The bones are therefore subjected to greater direct forces, and a stress fracture will often be the result. For this reason, there is a large correlation between fitness level and the occurrence of stress fractures. In other words, the more in shape you are, the better your muscles are at distributing the forces associated with running and other activities.

Women are often considered to be at a greater risk for stress fracture as well, particularly women with low levels of estrogen. Estrogen plays a role in reshaping the bone – if this mechanism is lost, the stresses of running and walking can often outpace the remodeling of the bone. Other factors involved in an increased risk of stress fracture include old, worn-out running shoes that have lost their shock absorbing capabilities, a difference in limb length, changes in running surfaces (such as moving from grass or a rubber track to cement) and differences in running style.

The symptoms of a stress fracture include tenderness over the area and pain upon activity. There may be some swelling in the area as well, though this is not as common. Your doctor will diagnose a stress fracture using these clinical signs as well as with an x-ray. Stress fractures are usually treated by reducing activity, and putting the effected leg in a non-weight bearing cast.

Central Florida Foot & Ankle Center, LLC
101 6th Street N.W.
Winter Haven, FL 33881
Phone: 863-299-4551
http://www.FLFootandAnkle.com