Normative Glenoid Bone Mineral Density Values in a Non-Pathologic Adult Population: A Quantitative Computed Tomography Study with Age and Sex Stratification

Abstract

Objective: To establish age- and sex-specific normative computed tomography (CT) attenuation (Hounsfield unit, HU) reference values for the adult glenoid across cortical, subchondral, and trabecular regions, using opportunistic measurements from routine, non-dedicated thoracic CT, and to characterise their relationship with age and sex for preoperative shoulder arthroplasty planning. Materials and Methods: In this prospective cross-sectional study, 106 adults (31 men, 75 women; age range 18-69 years, mean 43.5 ± 14.6 years) without clinical or imaging evidence of glenohumeral joint pathology underwent high-resolution CT of the thorax on a 128-slice scanner for unrelated indications. On coronal images through the glenoid cavity, five standardised 2.5-mm square regions of interest (ROIs) were placed: subchondral cortical bone (SC), two trabecular layers (T1, T2), and two cortical rim regions (CO1, CO2). Mean HU values were compared by sex (independent-samples t-test) and age group (one-way ANOVA with Tukey post-hoc), and inter-regional correlations were assessed with Pearson’s r. Results: Cortical/subchondral attenuation (SC 729.4 ± 213.9 HU; CO1 711.5 ± 271.1 HU; CO2 630.6 ± 282.7 HU) was substantially higher than trabecular attenuation (T1 294.0 ± 124.1 HU; T2 201.9 ± 93.3 HU). Men had significantly higher HU values than women in the trabecular and cortical rim regions (T1: 388.5 vs 254.9 HU; T2: 286.4 vs 166.9 HU; CO1: 818.4 vs 667.3 HU; CO2: 782.1 vs 568.0 HU; all p ≤ 0.008); the subchondral region showed a similar but non-significant trend (p = 0.066). Trabecular HU declined significantly across age groups (ANOVA p = 0.003 for T1, p = 0.019 for T2), with the steepest fall after the sixth decade and most pronounced in women, whereas cortical attenuation declined more gradually and did not reach significance (p = 0.053–0.126). All five regions were positively inter-correlated (r = 0.41–0.78, p < 0.001), with the strongest relationship between the two trabecular layers (r = 0.78). Conclusion: Glenoid trabecular bone shows the steepest sex- and age-related decline in attenuation, while cortical bone is comparatively preserved. These locally derived normative HU values, obtainable opportunistically from routine thoracic CT without additional radiation, may assist radiologists and shoulder surgeons in preoperative bone-quality assessment, implant selection, and baseplate/screw trajectory planning for anatomic and reverse total shoulder arthroplasty.