Interrater and intrarater reliability of ultrasonographic measurements of acromion-greater tuberosity distance in healthy people.

Acromion-greater tuberosity (AGT) distance could potentially be used to assess rotator cuff tears and shoulder subluxation in patients with poststroke hemiplegia. The aim of this study was to assess the interrater and intrarater reliability of ultrasonographic measurements of AGT distance in healthy people prior to testing on patient populations. Twenty healthy individuals (9 male, 11 female) with a mean age of 21 years (SD ± 2) were recruited. Three final year physiotherapy students (mean age 23 years) recorded the ultrasonographic measurements of AGT distance by using a standardised protocol. Reliability was assessed by intraclass correlation coefficients (ICC) and standard error of measurements (SEM). The mean AGT distances, as measured by rater one, two, and three were 2.24 ± 0.45 cm, 2.27 ± 0.37 cm, and 2.21 ± 0.31, respectively. The interrater reliability coefficient was ICC = 0.79, and the intrarater reliability coefficients were 0.88, 0.84, and 0.91 for each rater. The SEM for the AGT distance measurements was ?0.15?cm for all three raters. Ultrasonographic measurements of AGT distance demonstrate good intrarater and interrater reliability in healthy individuals even when measured by three relatively inexperienced raters. It has potential to provide quantitative measurements for the clinical management of pathologies such as poststroke shoulder subluxation and rotator cuff tears.