A stress fracture occurs when the forces are much lower, but happen repetitively for a long period of time; these injuries are also known as fatigue fractures. Stress fractures are commonly seen in athletes who run and jump on hard surfaces, such as distance runners, basketball players, and ballet dancers.
A stress fracture can occur in any bone, but is commonly seen in the foot, shin, and hip bones. They rarely occur in the upper extremity because the weight of your body is not supported by your arms as it is in your legs.
Signs of a Stress FractureThe most common sign of a stress fracture is pain associated with activity. The pain of a stress fracture is usually predictable. This means that athletes usually know exactly how long into their run or work-out until the pain develops, and the pain typically resolves as soon as the body part is rested.
Any athlete with persistent pain that is not resolving should be evaluated to ensure there is no sign of a stress fracture. Because these overuse injuries have a typical course and common physical findings, the history and examination can be critical in the diagnostic evaluation. X-rays may not show a stress fracture, but they may show evidence of bone attempting to heal around the stress fracture. Further studies, including an MRI or bone scan may be necessary if the diagnosis is unclear or if the problem does not resolve with treatment.
How Stress Fractures OccurBone is constantly undergoing changes to adapt to its environment. When astronauts go into space, they are known to develop a thinning of the bone similar to osteoporosis. The reason is that their skeleton is not under the constant force of gravity, and the bone adapts to that environment. Stress fractures are usually seen in athletes who increase their level of activity over a short period of time. The increased demand placed on the bone causes the bone to remodel and become stronger in the areas of higher stress. However, if the response of the bone cannot maintain the pace of the repetitive demands, a stress fracture may result. Stress fractures are almost always the result of increasing duration or intensity of an activity too quickly for the body to adapt.
Another factor that can contribute to the development of a stress fracture are dietary abnormalities and menstrual irregularities. Because both factors contribute to bone health, any problems with diet (e.g. poor nutrition, anorexia, bulimia) or menstruation (amenorrhea) may place an individual at higher risk for a stress fracture. This is the reason that adolescent female athletes are at particularly high risk for development of a stress fracture.
Treatment of Stress FracturesThe best treatment of a stress fracture is to rest the injured body part. If there is no evidence that the stress fracture may displace (shift out of alignment), then avoiding the overuse activity may be sufficient treatment. However, if there is a concern of displacement of the stress fracture, then weight-bearing should be avoided (i.e. use crutches). Stress fractures of the hip are especially concerning, because if these fractures displace, surgery is mandatory, and long-term complications are a significant concern.
Other general stress fracture treatments include:
Boden BP and Osbahr DC "High-Risk Stress Fractures: Evaluation and Treatment" Am Acad Orthop Surg November/December 2000 vol. 8 no. 6 344-353