Ask a Sports Medicine Doc: Diagnosing and managing stress fractures
Q: My 16-year-old daughter runs for her high school cross-country team and she is getting worsening shin pain. What do you think is causing this?
Your daughter may be developing a stress fracture. I see this mainly in female athletes in their teen years and not uncommonly they are long-distance runners. There are multiple factors that can contribute to this condition, both intrinsic and extrinsic. Some intrinsic factors are bone metabolism, hormonal imbalances, fitness level, limb alignment and muscle endurance. Some extrinsic factors are dietary habits, footwear, a harder running surface and training regimens. Stress fractures commonly occur in areas of bone where there is poor blood supply to begin with. In this way, the bone is unable to repair the micro damage that occurs, as there is insufficient blood flow and thus compromised healing ability in that area. The more common areas affected by stress fractures are the lower leg bones (tibias) and two different small bones in the foot.
Most patients who are suffering from a stress reaction or later a stress fracture in the bone do not recall a particular injury or incident. Instead, patients report that the pain has been slowly worsening over several weeks. Their symptoms may correspond with a significant increase in their training.
In young people, it is important to determine if there is an underlying eating disorder. If so, there may be insufficient intake of calcium, vitamin D and total calories to allow the bone to heal. In addition, certain foods and beverages can be more acidic and in turn leach calcium and phosphate from the bone, thus compromising its microstructure. Stress fractures are common in young female athletes if they are suffering from the so-called female triad of an eating disorder, osteoporosis and amenorrhea.
In the office, these young athletes will be point-tender over the bone when I push on it. Hopping on one foot may worsen the pain. I obtain x-rays on these patients but not uncommonly they are normal. Only in chronic cases can you actually see a stress fracture in the bone on an X-ray. MRIs are much more sensitive, and they will demonstrate the condition much earlier. On an MRI, one can see fluid in the affected bone. However, MRIs are expensive and the findings probably won’t change the management of the condition, so getting an MRI is optional if the diagnosis is clear-cut.
As for treatment, it comes down primarily to rest. In addition, any metabolic or hormonal imbalances should be corrected. The recommended daily allowance of calcium and vitamin D is 1,000 mg and 800-1,000 IU respectfully. For young female athletes, I recommend taking 50 percent more than this. Medications such as bisphosphonates have been used to treat stress fractures, but I do not recommend these anti-osteoporosis medications in young athletes. Moreover, I do not recommend taking anti-inflammatory medications, as I want the athletes to feel the pain so it limits them accordingly. As for activities, athletes can try to maintain their cardiovascular fitness and strength by doing low-impact activities such as swimming, biking and weight training. Physical therapy is helpful. Namely, pulsed ultrasound has been shown to accelerate healing. Some early studies have also shown promise with extracorporeal shock wave therapy. Unfortunately, however, stress fractures can take months to resolve and can cost an athlete an entire sports season.
Dr. Rick Cunningham is a sports medicine specialist with Vail-Summit Orthopaedics. Do you have a sports medicine question you’d like him to answer in this column? Visit his website at http://www.vailknee.com to submit your query.
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