Interrater reliability of subacromial ultrasound measures in the hands of novice sonographers

INTRODUCTION: Ultrasound measures of subacromial structures are reliable in the hands of experienced sonographers, but it remains unknown if inexperienced clinicians can achieve a satisfactory level of interrater reliability. The aim was to investigate if standardised subacromial ultrasound measures are reliable in the hands of novice sonographers.

METHODS: Two novice sonographers performed standardised ultrasound measures on patients diagnosed with subacromial pain syndrome and asymptomatic shoulders. The measures were: supraspinatus tendon thickness (SUPRA), subacromial bursa thickness (SASD), acromio-humeral distance (AHD) and dynamic impingement (DI). Reliability and agreement were evaluated by intraclass correlation coefficient (ICC (2.1)), standard error of measurement, minimal detectable change, 95% limits of agreement, Bland-Altman plots and Cohen's unweighted κ.

RESULTS: Twenty-eight patients were recruited (28 symptomatic and 20 asymptomatic shoulders). The ICC of SUPRA ranged from 0.73 to 0.77. The ICC of SASD ranged from 0.41 to 0.88 and AHD from 0.68 to 0.72. Cohen's κ of DI in symptomatic shoulders was 0.29.

CONCLUSION: The interrater reliability of novice sonographers was found to be moderate to good when assessing SUPRA and AHD. For SASD and DI, the reliability ranged from poor to good. No significant differences in SUPRA and SASD thickness were found between symptomatic and asymptomatic shoulders.

FUNDING: None.

TRIAL REGISTRATION: Not relevant.