Monday, March 15, 2010
ROCHESTER, Minn. — When pain from increased physical activity doesn't go away in a couple of days, the cause could be a stress fracture. The March issue of Mayo Clinic Health Letter covers these tiny, partial bone fractures, why they occur and how they are treated.
Unlike standard fractures caused by trauma, stress fractures don't completely break through the bone. They typically feature one or more tiny cracks in the outer surface of the bone and are often related to an abrupt increase in the amount or intensity of physical activity. This type of stress fracture, called a fatigue fracture, can occur in normal, otherwise healthy bone. The most common locations for fatigue fractures are the weight-bearing bones of the middle foot (metatarsals) and the lower leg bones (tibia and fibula).
For older adults, weakening of the bones due to osteoporosis can contribute to a different type of stress fracture, called an insufficiency fracture. Instead of cracking during an abrupt increase in physical activity, bone cracks may occur lifting a bag of groceries or doing other everyday activities. The pelvis is a common location for an insufficiency fracture in older adults.
Regardless of the cause, the initial signs of a stress fracture often are subtle. At first, pain from stress fractures may be barely noticeable. Usually, the pain occurs when standing or during physical activity, but diminishes with rest. Without treatment, the pain with activity may continue to increase over time and even persist at rest.
Standard X-rays usually won't show stress fractures until several weeks after the pain starts. Advanced imaging, such as a computerized tomography (CT) scan or magnetic resonance imaging (MRI), may help confirm a diagnosis.
With treatment, many stress fractures heal within a month or two. The main treatment strategy is pain avoidance. Pain is a sign of movement on the edge of the fracture line; the fracture can't fuse or heal when the cracked edges are jostled.
Necessary pain avoidance strategies vary greatly by individual. Some people can walk pain free with a stress fracture. Others may need to keep all weight off the injured bone, relying on crutches, a cast, a supportive boot or wheelchair. Typically, patients can gradually increase weight-bearing activity after three to four weeks. Other treatment strategies include taking acetaminophen if pain is present when resting and applying ice several times a day to ease swelling and relieve pain. Rarely, surgery is needed to stabilize the stress fracture.
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