Inter-rater Reliability of Real-Time Ultrasound to Measure Acromiohumeral Distance

BackgroundReal-time ultrasound (RTUS) has been suggested as a reliable measure of acromiohumeral distance. However, to date, no vigorous assessment and reporting of inter-rater reliability of this method has been performed with the shoulder in a neutral position or with active and passive arm abduction.ObjectiveTo assess intrasession inter-rater reliability of using RTUS to measure acromiohumeral distance with the shoulder in a neutral position and with 60° active and passive abduction.Study DesignInter-rater intrasession reliability of repeated measures.SettingHuman performance laboratory.ParticipantsTwenty persons (12 male and 8 female) with an average age of 29.86 years (standard deviation, 7.8).MethodIn an inter-rater, intrasession study, RTUS was used to measure the acromiohumeral distance with the shoulder in a neutral position and with 60° of both active and passive abduction.Main Outcome MeasureAcromiohumeral distance.ResultsIntraclass correlation coefficient (ICC)2.1 scores ranged between 0.65-0.88 (standard error of the mean = 0.81-1.2 mm and minimal detectable differences with 95% confidence = 2.2-2.3 mm) for inter-rater intrasession reliability.ConclusionRTUS was found to have fair to good inter-rater reliability as a tool to measure acromiohumeral distance with the shoulder in a neutral position and with 60° of both active and passive arm abduction.