A Pilot Prospective Study to Validate Point-of-Care Ultrasound in Comparison to X-Ray Examination in Detecting Fractures

Ultrasound Med Biol. 2020 Jan;46(1):11-19. doi: 10.1016/j.ultrasmedbio.2019.09.006. Epub 2019 Oct 1.

Abstract

Despite its limitations, conventional radiography is the method of choice for fracture evaluation in the emergency department. Only a few studies, moreover in limited populations, have evaluated the possible benefits of ultrasound (US), and especially of point-of-care ultrasound (POCUS), in the diagnosis of fractures. We sought to compare the accuracy of POCUS with that of conventional radiography in the diagnosis of bone fractures. This prospective study with a non-randomly allocated convenience sample was conducted at two academic medical centers. Four physicians, with focused training in musculoskeletal POCUS, evaluated consecutive patients with suspected orthopedic injury. US and X-ray examination results were treated as dichotomous variables with either fracture present or fracture absent. Descriptive statistics were calculated in addition to prevalence, sensitivity, specificity, positive predictive value and negative predictive value including 95% confidence intervals (CIs). Cohen's κ coefficient was determined as a measurement of the level of agreement. Four hundred sixty-nine patients (404 adult and 65 pediatric) ranging in age from 1-97 y were enrolled at two different hospitals. Seven hundred six examinations, both US and X-ray, were performed in 634 suspected fractures in adults (age ≥18 y) and 72 in children. On physical examination, swelling, localized hematoma and functional limitation were found in 64.61%, 34.97% and 53.52, respectively. The sensitivity of US examination was 93.89% (CI: 89.74%-96.49%) for all patients and 94.30% (CI: 89.77%-96.98%) and 91.67% (CI: 76.41%-97.82%) in adult and pediatric groups, respectively. Specificity was 94.13% (CI: 91.53-95.99), 94.56% (CI: 91.89-96.41) and 88.89% (CI: 73.00-96.38) for the whole group, adults and children, respectively. The positive predictive value was 88.48% (CI: 83.62%-92.08%), 88.35% (CI: 82.97%-92.24%) and 89.19% (CI: 73.64%-96.48%) for the whole group, adults and children, respectively. The negative predictive value was 96.98% (CI: 94.86%-98.27%), 97.43% (CI: 95.31%-98.64%) and 91.43% (CI: 75.81%-97.76%) in the three groups, respectively. Cohen's κ coefficient revealed high agreement of 0.87 for both the whole group and adult patients and 0.81 for pediatric patients. We found that POCUS has significant diagnostic accuracy in evaluating fracture compared with plain radiography, with excellent sensitivity, specificity and positive and negative predictive values.

Keywords: Fractures; Point-of-care ultrasound; Trauma; Ultrasound; X-rays.