Low glenoid neck Hounsfield units predict patients at high risk of mechanical complication after total shoulder arthroplasty

Background Computed tomography Hounsfield units (HUs) estimate bone mineral density, but their predictive value for total shoulder arthroplasty (TSA) mechanical complications is unknown. This study assessed whether glenoid HU (gHU) can be used to predict mechanical complication risk. Methods In this retrospective cohort study at a single tertiary academic center (January 2011-April 2024), pre-operative computed tomography scans from 250 TSAs in 233 patients were independently reviewed by 3 interdisciplinary reviewers to measure gHU. Mechanical complications, including periprosthetic or intraoperative fractures and aseptic implant loosening, were identified and stratified by gHU. Inter-rater reliability was assessed with the intraclass correlation coefficient. Receiver operating characteristic analysis identified optimal gHU thresholds. Risk-group comparisons used chi-square tests and multivariable logistic regression. Results Among 250 TSAs in 233 patients, intraclass correlation coefficient for gHU measurement was 0.90 (95% confidence interval 0.87-0.92). Receiver operating characteristic analysis yielded a cutoff of 177 HU (area under the curve 0.59; sensitivity 39%; specificity 81%). Mechanical complications occurred in 29% of cases with gHU