SPORTS TIP Stress Fractures

EXPERT CONSULTANTS: Barry P. Boden, MD, Matthew J. Matava, MD

What is a stress fracture? called a “tracer,” normally used by Each day, the body produces new bone the bone for repair, is injected into the to replace the bone that is broken down patient’s bloodstream. All of the bones by the stress of everyday living. Usually, will absorb some of the tracer, but if a this process is balanced, with the body bone is repairing a stress fracture, it will replacing the amount of bone lost. absorb more of the tracer at the fracture However, this balance may become site and will appear darker than uninjured upset with excessive physical training. bones (see figure). In many cases an MRI The body, due to several factors, may is preferable since there is no radiation not produce sufficient bone. As a result, exposure, the test takes less time, microcracks, called “stress fractures,” and MRIs are better than bone scans can occur in the bone. at specifying different types of bone Dark regions on the above bone scan or soft tissue abnormalities. The most common cause of stress indicate stress fracture of the first rib. fractures is an abrupt increase in the How is a stress fracture treated? duration, intensity, or frequency of physical lower extremity in running activities, and Stress fractures may be broadly classified activity without adequate periods of rest. the foot in gymnastics and basketball. as either low-risk injuries (less likely In addition to mechanical influences, to become more serious fractures) systemic factors (such as hormonal How will I know if I have or high-risk injuries (more likely to imbalances), nutritional deficiencies, a stress fracture? become serious fractures). Low-risk sleep deprivation, and metabolic Stress fractures produce pain in a limited stress fractures infrequently require bone disorders may contribute to area directly over the point of the bone expensive imaging modalities such as the development of stress fractures. where the fracture has occurred. The pain bone scans or MR imaging. Most cases Furthermore, some female athletes is exacerbated by activity and is relieved can be diagnosed on the basis of a who train competitively develop eating with rest. Bone tenderness is the most thorough history, physical examination, disorders and/or amenorrhea (infrequent obvious finding on physical examination. and radiographs. A rest period of one menstrual periods). Both conditions Hopping or jumping on a leg with a to six weeks of limited weight bearing may lead to a low estrogen state with stress fracture will cause increased pain. progressing to full weight bearing may resultant decreased bone mineral density be necessary (see box). Return to activity and an increased risk of stress fractures. X-rays may not be helpful in diagnosing should be a gradual process. Low-impact an early stress fracture because the bone Stress fractures are frequently seen in activities, such as swimming or biking, can often appears normal and the micro cracks military recruits and athletes, especially be performed to maintain cardiovascular are not visible. After several weeks of runners. Although stress fractures have conditioning once the pain subsides. rest, the bone begins to repair itself and been described in nearly every bone of When the patient can comfortably often demonstrates a healing reaction the human body, they are more common perform low-impact activities for prolonged or callus on X-ray. in the lower extremity weight-bearing periods without pain, high-impact bones. Stress fractures may be associated The diagnosis of an early stress fracture exercises may be initiated. Typically, with a specific sport such as the humerus can usually be confirmed by a bone scan the athlete gradually increases jogging in throwing sports, the ribs in golfing or magnetic resonance imaging (MRI). mileage and eventually returns and rowing, the spine in gymnastics, the In a bone scan, a radioactive substance to sport-specific activities. Stress Fractures

High-risk stress fractures, involving areas such as the hip, have a predilection for Treating Lower Extremity Stress Fractures progressing to complete fracture; therefore, they require a more aggressive approach. In athletes who have chronic pain and Activity Progression 1. Non-weightbearing, non-impact activities like swimming or biking. normal findings on initial X-rays, a bone scan or MRI is recommended. Because 2. Weightbearing, non-impact activities like of the high complication rate, high-risk a stair machine or a treadmill. stress fractures should be treated like 3. Weightbearing, impact activities like jogging. traumatic fractures—often with a cast and occasionally with surgery when necessary. Intensity Progression 1. Low intensity, short duration. 2. Low intensity, increased duration. How are stress fractures prevented? 3. Higher intensity, short duration. Stress fractures are best managed by 4. Higher intensity, increased duration. prevention. Training errors, such as 5. Advance to next activity level. an excessive increase in intensity, are the most frequent culprits and should be corrected. New activities, such as hill running or running on a hard surface, may be contributing factors. Athletes, coaches, military personnel, and parents should be educated about the deleterious effects of overtraining and the importance of periodic rest days. In addition, female athletes and their coaches need to be alerted to the adverse effects of eating disorders and hormonal abnormalities.

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