Rater Variation in Ultrasound Detection of Dorsal Cortex Screw Protrusion in Fixed-Angle Volar Plating of the Distal Radius

This study evaluates rater accuracy and variation for the purpose of using intraoperative ultrasound (US) imaging to detect dorsal screw protrusion during fixed-angle volar plating of distal radius fractures. Stabilizing volar plates and screws with varying lengths of dorsal protrusion were applied to 10 cadaver wrist pairs. After a brief training session, seven surgeons without prior ultrasound experience assessed screw protrusion on two separate occasions using a diagnostic ultrasound machine. Screw protrusions were visually confirmed after data collection was completed. Statistical analyses included percent agreement and Cohen’s kappa for accuracy and intra- and inter-rater reliability, sensitivity, specificity, and positive and negative predictive values. Only two out of seven raters met acceptable levels of accuracy and consistency. Our findings inform us that accuracy and consistency of ultrasound-guided detection of dorsal screw protrusion are negatively impacted by rater variation. Further investigations are needed to improve rater effectiveness. (Journal of Surgical Orthopaedic Advances 28(4):260-267, 2019) Key words: distal radius fractures, ultrasound imaging, screw protrusion, volar plating, diagnostic testing, measurement