Ultrasound-assisted measurement of humeral version: a radiation-sparing alternative to whole-humerus computed tomography

Background: Humeral version is a key parameter in preoperative planning for reverse total shoulder arthroplasty (RTSA). Although computed tomography (CT) of the entire humerus is required to measure humeral version accurately, standard preoperative imaging typically includes only the scapula and proximal humerus, leading to additional radiation exposure. Ultrasound-assisted humeral torsion measurement using the bicipital groove has shown strong correlations with CT but lacks clinically applicable angle calculation methods. Methods: In this study, we evaluate whether humeral version can be accurately calculated using proximal humerus CT combined with ultrasound without additional imaging of the distal humerus. Thirty-nine patients who underwent RTSA between March 2021 and May 2022 were included. Preoperative whole-humerus CT and ultrasound-assisted version measurements were compared. Results: Intra-and inter-tester reliability of the ultrasound-assisted measurements showed intraclass correlation coefficients (ICCs) of 0.924 (95% CI, 0.857–0.960) and 0.872 (95% CI, 0.727–0.942), respectively. The mean humeral version measured by CT was 30.4°±15.1°, and 32.8°±14.5° by the ultrasound-assisted method. A strong correlation was observed between the two methods (Pearson’s r=0.915, P<0.001; concordance correlation coefficient=0.903). The ICC between the two methods was 0.905 (95% CI, 0.813–0.951). Bland-Altman analysis showed a mean difference of 2.38°, with 95% limits of agreement from –14.37° to 9.61°, indicating high agreement. Conclusions: These findings suggest that ultrasound-assisted measurement combined with proximal humerus CT is a reliable and accurate alternative to whole-humerus CT, reducing radiation exposure and cost. Level of evidence: III.