Study design: Systematic literature review and meta-analysis.
Objectives: To evaluate the diagnostic accuracy of clinical tests to identify stress fractures in the lower limb.
Background: Stress fractures are a bone-related overuse injury primarily occurring in the lower limb and commonly affecting running athletes and military personnel. Physical examination procedures and clinical tests are suggested for diagnosing stress fractures; however, data on the diagnostic accuracy of these tests have not been investigated through a systematic review of the literature.
Methods: A systematic review was conducted in 8 electronic databases to identify diagnostic accuracy studies, published between January 1950 and June 2011, that evaluated clinical tests against a radiological diagnosis of lower-limb stress fracture. Retrieved articles were evaluated using the Quality Assessment of Diagnostic Accuracy Studies tool, and a meta-analysis was performed where appropriate.
Results: Nine articles investigating 2 clinical procedures, therapeutic ultrasound (n = 7) and tuning fork testing (n = 2), met the study inclusion criteria. Meta-analysis was used to statistically analyze the data extracted from the ultrasound articles and demonstrated a pooled sensitivity of 64% (95% confidence interval [CI]: 55%, 73%), specificity of 63% (95% CI: 54%, 71%), positive likelihood ratio of 2.1 (95% CI: 1.1, 3.5), and negative likelihood ratio of 0.3 (95% CI: 0.1, 0.9). Tuning fork test data could not be pooled; however, sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio ranged from 35% to 92%, 19% to 83%, 0.6 to 3.0, and 0.4 to 1.6, respectively.
Conclusion: The results of this systematic review do not support the specific use of ultrasound or tuning forks as standalone diagnostic tests for lower-limb stress fractures. As the overall diagnostic accuracy of the tests investigated is not strong, based on the calculated likelihood ratios, it is recommended that radiological imaging should continue to be used for the confirmation and diagnosis of stress fractures of the lower limb.
Level of evidence: Diagnosis, level 1a-.J Orthop Sports Phys Ther 2012;42(9):760-771, Epub 19 July 2012. doi:10.2519/jospt.2012.4000.