Diagnostic Accuracy of Point-of-Care Ultrasound for Hip Effusion: A Multicenter Diagnostic Study

Abstract

Study objective To determine the diagnostic accuracy of point-of-care ultrasound (POCUS) performed by pediatric emergency physicians for the diagnosis of hip effusion. Methods This multicenter, prospective study was conducted in 5 pediatric emergency departments (PEDs) in the United States and Australia from October 2019 to October 2023. Children aged 18 years and younger who presented to the PED with clinical presentation requiring radiology-performed ultrasound (RADUS) for evaluation of a hip effusion were eligible. Participants received POCUS by pediatric emergency physicians credentialed to perform hip ultrasound and RADUS of both hips. Physicians categorized their POCUS findings as “yes” or “no” for the presence of hip effusion based on standard measurement definition. The primary outcome was the diagnostic accuracy of POCUS using RADUS as the reference standard in diagnosing hip effusion. Results A total of 161 participants, aged 2 months to 15 years, were enrolled (mean age 62.4 ± 3.1 months), with 322 hips scanned. A total of 18 credentialed pediatric emergency physicians enrolled the participants, with 3 physicians accounting for enrollment of 99/161 (61.5%) of the subjects. For the 3 high-volume pediatric emergency physicians, POCUS had a sensitivity of 98.1% (95% confidence interval [CI] 88.8% to 99.9%) and specificity of 97.8% (95% CI 86.8% to 99.9%). Among the remaining 15 physicians, POCUS had a sensitivity of 83.3% (95% CI 61.8% to 94.5%) and specificity of 97.4% (95% CI 84.6% to 99.9%). POCUS identified 77 hip effusions and RADUS identified 82 hip effusions. In per hip analysis, POCUS had a sensitivity of 89.3% (95% CI 80.6 to 95.0%) and specificity of 99.2% (95% CI 97.0 to 99.9%). Conclusion POCUS had high sensitivity and specificity for diagnosing hip effusion in children when performed by a small group of pediatric emergency physicians with focused training, suggesting that accurate diagnosis may be feasible in similarly trained individuals.