Female Patients Exhibit a Narrower Glenoid Rim and Lower Bone Density in the Anteroinferior Quadrant Compared With Male Patients

PURPOSE: The purpose of this study was to evaluate sex-based differences in glenoid rim morphology and bone density relevant to arthroscopic Bankart repair. METHODS: This retrospective study assessed differences in glenoid rim morphology between sexes in patients with shoulder instability and uninjured control subjects who underwent a magnetic resonance imaging scan of the shoulder at a single institution between 2014 and 2023. The glenoid neck-to-face ratio was calculated to compare differences in steepness of the glenoid neck. Bone density was analyzed in a separate cohort of uninjured subjects using computed tomography scans, with Hounsfield units measured in the anteroinferior (4-6 o'clock) quadrant and the mid-anterior (3 o'clock) region. RESULTS: A total of 204 patients (51 shoulders per cohort) were included for the glenoid morphology analysis, and a separate group of 102 uninjured patients was included for bone density evaluation. The neck-to-face ratio differed significantly between male patients and female patients in both the instability cohort (P < .001) and the uninjured cohort (P < .001). There were no significant differences between instability and uninjured cohorts of the same sex (P = .22 and P = .43). Bone density in the anteroinferior quadrant of the glenoid was significantly lower in female patients (median: 272.5 HU) compared with male patients (median: 303.0 HU; P = .009), whereas the mid-anterior region showed no significant differences (P = .65). CONCLUSIONS: Female patients exhibit a significantly narrower glenoid rim compared with male patients, with no differences between instability and uninjured subjects of the same sex. Bone density at the anteroinferior quadrant (4-6 o'clock) was also lower in female patients, whereas no difference was observed at the mid-anterior region (3 o'clock). LEVEL OF EVIDENCE: Level III, retrospective comparative study.