Gender bias in glenosphere size selection in reverse total shoulder arthroplasty: Glenoid size correlates with height and weight, not just gender

Background

Optimal glenosphere selection is critical for successful outcomes following reverse total shoulder arthroplasty (rTSA). This study primarily aimed to determine patient-specific variables associated with dimensions of native glenoid anatomy. Secondarily, we aimed to determine the distribution of glenosphere sizes selected in male and female patients with similar-sized glenoids.

Methods

Computed tomography scans from patients undergoing rTSA with a diagnosis of cuff arthropathy or irreparable cuff tears were included for analysis. Variables collected included the following: age, gender, height, weight, and glenosphere size. Glenoid dimensions were measured, and interobserver reliability was calculated. Correlation coefficients were calculated for all variables. Multivariate predictive regression models were utilized to determine correlations between patient variables and glenoid width and height.

Results

One hundred and eighteen patients (46% male, 54% female) were included for analysis. Taller and male patients were significantly associated with increased glenoid height (P = .0096 and P = .0003, respectively). Females, shorter patients, and patients with decreased body weight were significantly associated with decreased glenoid width (P = .01, P < .0001, and P = .01, respectively). Through stepwise selection, patient height was most strongly associated with glenoid width (P < .0001). For glenoid widths between 25 and 30 mm, there was a significant variation in selected glenosphere sizes based on gender (P < .0001).

Discussion

Patient gender and height are significantly associated with glenoid height and width. There remains a strong tendency towards gender bias when selecting glenosphere sizes for patients undergoing rTSA with similar-sized glenoids. This data highlights the importance of considering patient height as well as gender when considering glenoid component size in the setting of rTSA.