There have been a few studies that have demonstrated that bedside ultrasound has a high sensitivity and specificity for fracture diagnosis.
Researchers in Italy compared the accuracy of US to that of plain radiography (the gold standard) in 204 children (age range, 2–17 years) presenting to an emergency department with possible hand fractures.
Phalangeal or metacarpal fractures were detected by radiography in 79 patients (39%). Radiologists blinded to radiography results evaluated all patients’ symptomatic hands with US Compared with radiography, US detected fractures with 91% sensitivity and 98% specificity. Pediatric emergency physicians blinded to the results received about 2 hours of hand US training and evaluated 153 of the children. Emergency physicians detected fractures by US with 92% sensitivity and 97% specificity, and were in excellent agreement with radiologists’ findings (κ=0.9).
In another ER study out of Turkey, investigators assessed the sensitivity and specificity of emergency physician-performed ultrasound and radiography for detecting lateral malleolar fractures in a convenience sample of 120 adults who presented to a single emergency department in Turkey with ankle injuries and lateral malleolus tenderness. Computed tomography (CT) was performed to adjudicate discrepancies between ultrasound and x-ray findings. Evaluation of x-ray or CT images by an orthopedic surgeon was the gold standard.
Fractures were detected in 47 patients by ultrasound and in 39 by radiography. CT was performed in 49 patients. The sensitivity and specificity of ultrasound were 100% and 93%, respectively; for plain films, 93% and 100%, respectively.
The results for use of ultrasound for adequacy of fracture reduction is not as positive. A prospective single institution study showed suboptimal results. The study involved sixteen emergency physicians who were novices in ultrasound-facilitated fracture reduction. These ED pysicians underwent a 1-hour simulation training session before the study. Pre- and post-reduction ultrasound images were taken with a linear probe placed in two orthogonal planes, corresponding to the lateral and anterior-posterior radiographic views. Correlating post-reduction fluoroscopic images were reviewed by a single pediatric orthopedic surgeon and used as the reference standard.
Among 100 patients (median age, 12 years), ultrasound identified 4 of 8 fractures that were inadequately aligned (sensitivity, 50%) and 82 of 92 fractures that were properly aligned (specificity, 89%), yielding a negative predictive value of 95% and positive predictive value of 29% for inadequate alignment. Obviously, there is a learning curve for the use of POCUS to determine adequacy of bony alignment post-reduction and a 1 hour simulation training is not a lot of training.