Point-of-care bedside ultrasound examination for the exclusion of clinically significant ankle and fifth metatarsal bone fractures; a single blinded prospective diagnostic cohort study

Aniek Crombach,Heleen Lameijer,Jan C Ter Maaten,Nasim Azizi,Mostafa El Moumni

doi:10.1186/s13047-020-00387-y

Abstract

ObjectiveThe aim of this study was to assess the diagnostic value of point-of-care bedside ultrasound (PoCUS) as in usual clinical practice in suspected ankle and fifth metatarsal bone fractures, compared to the standard of radiographic imaging.MethodsThis prospective study included patients ≥17 years presenting to the Emergency Department with ankle trauma and positive Ottawa Ankle Rules. All patients underwent PoCUS of the ankle by a (resident) emergency physician, the images were assessed by an ultrasound expert. Both were blinded for the medical history and clinical findings of the patients. Radiography of the ankle followed, evaluated by a radiologist blinded from the PoCUS findings. Primary outcome measures were sensitivity and specificity of PoCUS.ResultsA total of 242 patients were included, with 35 (22%) clinically significant (non-avulsion) fractures observed with radiography. The sensitivity of PoCUS in detecting clinically significant fractures by all sonographers was 80.0% (95% Confidence Interval (CI) 63.0 to 91.6%), specificity 90.3% (95% CI 83.7 to 94.9%), positive predictive value 70.0% (95% CI 57.0 to 80.3%) and the negative predictive value 94.1% (95% CI 89.1 to 96.9%). The sensitivity of PoCUS in detecting clinically significant fractures by the expert was 82.8% (95% CI 66.3 to 93.4%), specificity 99.2% (95% CI 95.5 to 99.9%), positive predictive value 96.7% (95% CI 80.3 to 99.5%) and the negative predictive value 95.3% (95% CI 91.0 to 98.2%).ConclusionPoCUS combined with the OAR has a good diagnostic value in usual clinical practice in the assessment of suspected ankle and fifth metatarsal bone fractures compared to radiographic imaging. More experience with PoCUS will improve the diagnostic value.Trial registrationRegistered in the local Research Register, study number 201500597.

Highlights

Foot and ankle injuries are one of the most frequent reasons to visit the Emergency Department (ED), but the diagnostic instruments used are highly inefficient [1]
The sensitivity of point-of-care bedside ultrasound (PoCUS) in detecting clinically significant fractures by all sonographers was 80.0% (95% Confidence Interval (CI) 63.0 to 91.6%), specificity 90.3%, positive predictive value 70.0% and the negative predictive value 94.1%
The sensitivity of PoCUS in detecting clinically significant fractures by the expert was 82.8%, specificity 99.2%

Summary

Introduction

The relative low probability of fractures causes frequent unnecessary radiation exposure, together with burdening of the patient and costs, time, and crowding in the ED. A few studies have assessed the use of point-of-care bedside ultrasound (PoCUS) in diagnostics of foot and ankle injuries showing a sensitivity ranging from 87.3 to 100% and specificity ranging from 90.1 to 99.1%. These studies show that when PoCUS is used in OAR positive patients, there can be an approximately 80% reduction of radiological assessment. The studies on the matter are all subjective to bias regarding PoCUS, because of unblinded designs, limited amount of and selected sonographers and non-consecutive inclusion [2, 5]

Methods

Results

Discussion

Conclusion