Diagnostic Accuracy of Ultrasound for Upper Extremity Fractures in Children: A Systematic Review and Meta-analysis

Objective: Ultrasound has an excellent diagnostic accuracy for fractures that is reportedly comparable to plain radiographs. We aim to summarize the diagnostic accuracy of ultrasound for upper extremity fractures in children.

Methods: Databases were searched from inception through November 2019 using pre-defined index terms, including "ultrasound," "fractures of upper extremities" and "children". The study is reported using Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies (PRISMA-DTA). Meta-analysis of the diagnostic accuracy of ultrasound for fractures was conducted using the random-effects bivariate model. Subgroup analysis of fracture site (elbow vs non-elbow fractures) was also performed. Meta-regression was performed to determine if the site of fracture affected the diagnostic accuracy.

Results: Thirty-two studies were identified in the meta-analysis. Ultrasound for fractures of the upper extremities has a sensitivity: 0.95 (95% CI: 0.93-0.97), specificity: 0.95 (95% CI: 0.91-0.98), positive likelihood ratio: 21.1 (95% CI: 10.8-41.5) and negative likelihood ratio: 0.05 (95% CI: 0.03-0.07), with an area under ROC (AUROC) curve of 0.98 (95% CI: 0.97-0.99). Subgroup analysis for elbow fracture showed ultrasound has a sensitivity: 0.95 (95% CI: 0.86-0.98), specificity: 0.87 (95% CI: 0.76-0.94), positive likelihood ratio: 7.3 (95% CI: 3.7-14.4) and negative likelihood ratio: 0.06 (95% CI: 0.02-0.16), with an AUROC of 0.96 (95% CI: 0.94-0.97). Meta-regression suggested the fracture sites would affect diagnostic accuracy of ultrasound (elbow vs non-elbow, p < 0.01).

Conclusions: Current evidence suggests ultrasound has excellent diagnostic accuracy for non-elbow upper extremity fractures in children, serving as an alternative diagnostic modality to plain radiographs.