Development and Assessment of 3-Dimensional CT Measures of Proximal Humeral Bone Density: A Comparison to Established 2D Measures and Intraoperative Findings in Patients Undergoing Shoulder Arthroplasty

Abstract Background The purpose of this study was to develop novel 3D measures of bone density from CT scans and to compare them with validated 2D radiographic assessments of bone density. Patient demographic data were also analyzed to see if there were any predictors of bone density (age, sex, etiology). Methods The study group consisted of two hundred and ninety consecutive patients undergoing primary shoulder arthroplasty surgery (total anatomic, reverse and hemiarthroplasty). All underwent preoperative CT imaging. Three 3D CT measurements (Metaphysis Cancellous, Metaphysis Cortical and the Proximal Diaphysis) were developed and automated into software. The developed 3D measurements were compared with validated 2D measures (Tingart and Gianotti Index). Patient demographic data was correlated with these measurements. The difference between the size of the final sounder and of the final stem was calculated as the Delta. Results There was moderately strong correlation between Tingart and Gianotti measures (0.674, p Figure 3 ). Tingart (AUC 0.87, 95% CI 0.82-0.91) and 3D Metaphysis Cancellous (AUC 0.78, 95% CI 0.72-0.84) had the highest correlation. These were significantly more than other measures of bone density (p (ANOVA F-ratio of 42.6, P Conclusion This study demonstrates that automated measures of bone density can be obtained from 3D CT scans. Of the three novel 3D measurements of bone density, the humeral Metaphysis Cancellous measurement was most correlated to the known 2D measures, and most correlated to the intra-operative assessment of bone density (delta).