From the Guidelines
Diagnosis of stress fractures should start with plain radiographs, followed by MRI if clinical suspicion remains high despite negative X-rays, as recommended by the most recent guidelines 1. The diagnosis of stress fractures requires a combination of clinical assessment and imaging studies. Initially, a thorough history and physical examination should be performed, focusing on risk factors such as recent changes in activity level, improper footwear, or biomechanical abnormalities. Patients typically present with localized pain that worsens with activity and improves with rest. On examination, there may be point tenderness, mild swelling, and pain with percussion or vibration over the affected area.
Plain radiographs should be ordered first, though they may be negative in early stress fractures, with changes often appearing 2-3 weeks after symptom onset, as noted in the 2024 update of the ACR Appropriateness Criteria 1. If clinical suspicion remains high despite negative X-rays, advanced imaging is warranted.
- MRI is the gold standard with nearly 100% sensitivity, showing bone marrow edema and fracture lines, making it the preferred next step in diagnosis 1.
- Bone scans are highly sensitive but less specific than MRI.
- CT scans can help visualize cortical fractures but are less sensitive for early stress reactions.
For high-risk stress fractures, such as those in the femoral neck, navicular, or fifth metatarsal base, early advanced imaging is recommended even with negative X-rays to prevent progression to complete fracture, as these fractures are prone to nonunion or delayed union 1. Early diagnosis is crucial as continued loading of an undiagnosed stress fracture can lead to complete fracture, delayed healing, and prolonged recovery time. The 2024 update of the ACR Appropriateness Criteria also emphasizes the importance of identifying and managing risk factors to prevent progression to complete fracture 1.
From the Research
Diagnosis of Stress Fracture
- Stress fractures are part of a continuum of changes in healthy bones in response to repeated mechanical deformation from physical activity 2
- Individuals with stress fractures present with focal tenderness and local pain that is aggravated by physical activity and reduced by rest 2
- Simple clinical tests can assist in diagnosis, but more definitive imaging tests will eventually need to be conducted if a stress fracture is suspected 2
Imaging Tests for Diagnosis
- Plain radiographs are recommended as the initial imaging test 2, 3, 4, 5, 6
- Magnetic resonance imaging (MRI) has higher sensitivity and is more likely to detect the injury sooner 2, 3, 4
- MRI is highly sensitive with findings ranging from periosteal edema to bone marrow and intracortical signal abnormality 4
- Bone scintigraphy and computed tomography (CT) are also possible options for diagnosis 3, 4, 5
Clinical Presentation and Risk Factors
- Stress fractures should be considered in patients who present with tenderness or edema after a recent increase in activity or repeated activity with limited rest 3
- Risk factors include female sex, white ethnicity, older age, taller stature, lower aerobic fitness, prior physical inactivity, greater amounts of current physical training, thinner bones, cigarette smoking, and inadequate intake of vitamin D and/or calcium 2
- Medial tibial stress syndrome (shin splints) can be distinguished from tibial stress fractures by diffuse tenderness along the length of the posteromedial tibial shaft and a lack of edema 3
Treatment and Prevention
- Treatment involves first determining if the stress fracture is of higher or lower risk; these are distinguished by anatomical location and whether the bone is loaded in tension (high risk) or compression (lower risk) 2
- Low-risk stress fractures can be initially treated by reducing loading on the injured bone through a reduction in activity or by substituting other activities 2
- Higher-risk stress fractures should be referred to an orthopedist 2
- Prevention strategies include modifications to physical training programs, use of shock absorbing insoles, vitamin D and calcium supplementation, modifications of military equipment, and leadership education with injury surveillance 2