Diagnostic accuracy of point-of-care ultrasound (PoCUS) for shoulder dislocations and reductions in the emergency department: a diagnostic randomised control trial (RCT)

Background Following blunt trauma, diagnosis of shoulder dislocation based on physical examination alone is difficult due to possible concurrent proximal humeral fractures. X-rays are therefore used to confirm diagnosis. Results from recent observational studies comparing diagnostic accuracy of point-of-care ultrasound (PoCUS) with X-rays for shoulder dislocation have been encouraging. The aim of this study was to determine whether PoCUS improves diagnostic accuracy when used with physical examination for the diagnosis of shoulder dislocation, proximal humeral fracture and ascertaining successful reduction in the ED. Methods A prospective, single-centre, open, parallel randomised control study over a 6-month period was used to answer the research question and test the null hypothesis. Consecutive eligible adult patients attending the ED of Mater Dei Hospital in Malta were randomised to either the control (C) (physical examination only) or experimental group (E) (physical examination and a two-point PoCUS scan). The study objectives were to measure diagnostic accuracy for both examinations for detecting shoulder dislocation, any associated proximal humeral fractures and confirming reduction. X-rays were used as reference standard for both groups. Results 1206 patients were enrolled in this study (C n=600, E n=606). 290 dislocations (C n=132 and E n=158), 332 proximal humeral fractures (C n=154 and E n=178) and 278 reductions (C n=130 and E n=148) were analysed. A statistically significant difference (p<0.001) was found between the two groups for diagnostic accuracy in shoulder dislocation (C=65%, likelihood ratio (LR)+=2.03 and LR-=0.35 and E=100%, LR+=infinity and LR-=0), proximal humeral fractures (C=45.7%, LR+=1.23 and LR-=0.52 and E=98.3%, LR+=103.9 and LR-=0.03) and reduction (C=68.7%, E=100%). The null hypothesis for this study was thus rejected. Conclusions The addition of PoCUS to a physical examination significantly improves diagnostic accuracy for dislocations, proximal humeral fractures and reduction confirmation.