investigation

Last reviewed 01/2018

During the early stages of a stress fracture injury there may be difficulty in identifying the fracture. A few weeks later radiology may reveal a small transverse defect in the cortex. If the injury is aggravated by further repeated stress then there may be, in addition, localized periosteal bone formation.

• note that a normal x-ray does not exclude a stress fracture, so if the clinical suspicion remains proceeding to a magnetic resonance imaging (MRI) scan of the area of concern is appropriate
  • MRI may show an actual fracture line - however the typical MRI abnormality is periosteal and marrow oedema
  • other possible investigations:
    • isotope bone scans may also show stress fractures
      • however is a non-specific investigation and rarely needed beyond investigating rib fractures
    • single photon emission computing tomography (SPECT) scans (followed by a reverse gantry CT scan if positive) can be useful if a pars fracture is strongly suspected despite a normal MRI
    • CT adds detail
      • however with the exception of the further assessment of the pars interarticularis is not often required
    • Ultrasound scanning
      • may be diagnostic in cases with a fracture line, and thus a cortical break
      • not advocated in isolation

Reference:

• (1) ARC. Sports-Related Musculoskeletal Disorders. Reports on the Rheumatic Diseases 2008;14.