Within-day and day-to-day intrarater reliability of ultrasonographic measurements of acromion-greater tuberosity distance in healthy people.

Shoulder subluxation is subjectively assessed by a palpable increase in the distance between the acromion and the humerus. Diagnostic ultrasound has potential for objective assessment of this distance. We used portable ultrasound to measure the distance between the acromion and greater tuberosity (acromion-greater tuberosity [AGT] distance) and tested the intrarater reliability in healthy individuals prior to testing on stroke patients. Thirty-two healthy participants aged 51-85 years (mean 64.2+/-10.5) were recruited. Seated participants were scanned by a physiotherapist trained in shoulder ultrasound. Measurements were recorded on day 1 and again within 2 weeks. Reliability was assessed by intraclass correlation coefficients. The mean AGT distance was 1.68+/-0.41 cm for the left and 1.78+/-0.40 cm for the right shoulder. Within-day intrarater reliability coefficients were 0.99 and 0.98 for the left and right shoulders, respectively. Corresponding values for day-to-day reliability were 0.96 and 0.97. Portable diagnostic ultrasound is a quick and reliable method of assessing AGT distance in healthy individuals when measured by the same examiner.