Managing Stress Fractures In Athletes
Always question injured athletes about their dietary habits, in particular their ingestion of dietary calcium. A prospective study by Tenforde and co-workers in 2010 showed a decrease in stress fractures in runners when there was an increase of their dietary calcium and Vitamin D intake.7 A referral to an endocrinologist is appropriate when an athlete presents with any signs of an eating disorder or multiple stress fractures in a short span of time.
Essential Diagnostic Tips
In order to diagnose and treat stress fractures effectively, one must have a high index of suspicion during the initial clinical exam. Successful conservative treatment of a stress fracture is extremely dependent on timely diagnosis and initiation of treatment. Palpation of the injured area and careful documentation of the injury history are key components of making a proper diagnosis. Stress fractures are often accompanied by increased pain as the activity or workout progresses. This is the opposite of soft tissue injuries, which typically hurt more at the start.
One diagnostic test that works well is having the patient hop on the injured side. This produces sharp, pinpoint pain. One may also use the hop test as another test to determine if the bone is healed enough for the patient to return to activity.
Most physicians have radiographs readily available and with the advent of digital X-ray equipment, it is sometimes possible to pick up a stress fracture earlier than ever. It is important to keep in mind that negative radiographs should almost never rule out a stress fracture. Some bones such as the navicular or cuboid may never exhibit radiographic changes in the presence of a stress fracture. While metatarsal stress fractures can sometimes be present, it is typically at the point where the bone has healed and symptoms have subsided that there is radiographic evidence of bone healing.
If initial radiographs are negative and further testing is required, then the physician can choose between magnetic resonance imaging (MRI), Tc99 bone scintigraphy and computed tomography (CT) scanning. There is some debate as to whether MRI or bone scan is better for diagnosing a stress fracture.
Dobrindt and colleagues recently published an article supporting the use of bone scintigraphy.8 Three different observers studied bone scans without any clinical information about the patient for the diagnosis of stress injuries in 50 of 93 patients. Researchers found that the mean sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 97.3 percent, 67.4 percent, 77.7 percent, 95.6 percent and 83.5 percent respectively. An analysis showed a high agreement among the three different observers.
Research has shown MRI to have a higher specificity for detecting the exact location for the injury. However, one must use caution in interpreting MRI results as bone marrow edema, which is commonly associated with a stress reaction or stress fracture, can also be seen in asymptomatic individuals. Amol Saxena, DPM, observes that further testing and correlation with clinical symptoms is extremely important.9 Dr. Saxena had a patient who was being evaluated for a sesamoid injury via MRI of the feet and legs as a screening prior to signing a professional soccer contract. The athlete had spent the morning practicing with a lot of ball strikes and the physician read the MRI as multiple stress fractures of the metatarsals despite the fact that the patient did not have any symptoms in that area.
A CT scan is a much better option for some bones such as the navicular or cuboid, and when an MRI is inconclusive, and shows an increase of bone marrow edema. Computed tomography shows the cortex of bone much better than MRI.