Diagnostic Accuracy of Ultrasound for Adolescent Pelvic Avulsion Fractures: A Blinded Multirater Study

OBJECTIVE: Pelvic avulsion fractures are common injuries among adolescent athletes and are often evaluated with imaging modalities involving radiation to the pelvis. Ultrasound is a portable, accessible, inexpensive, radiation-free alternative, but its accuracy for diagnosing pelvic avulsions has not been well established. The purpose of this study is to evaluate the diagnostic accuracy of ultrasound detecting pelvic avulsion fractures in adolescents, including among clinicians without prior ultrasound training and radiologists. METHODS: Four clinicians with limited or no ultrasound experience and three radiologists individually reviewed 32 cases (age range 11-16). All raters were blinded to diagnosis and were shown one example case prior to review. Raters then identified whether an avulsion was present and, if so, which side was affected. RESULTS: The average number of correct diagnoses was 27 out of 32 cases (84.0%). There was no significant difference in diagnostic accuracy between clinicians and radiologists (p = 0.912). Diagnostic performance was strong with sensitivity of 90.48%, specificity of 76.62%, positive predictive value (PPV) of 88.08 and negative predictive value (NPV) of 80.82. A combined 71.4% of 2 radiographically silent avulsion fractures were correctly identified. CONCLUSION: Clinicians with minimal ultrasound training demonstrated accuracy in interpreting ultrasound images of pelvic avulsion fractures, suggesting ultrasound interpretation may be learnable. These findings support the use of ultrasound as a reliable adjunct imaging modality for diagnosing pelvic avulsion injuries in adolescent athletes, including in cases where radiographs appear inconclusive or normal. Greater emphasis should be placed on incorporating ultrasound into clinical practice to reduce unnecessary pelvic radiation exposure.