Reverse total shoulder arthroplasty (RTSA) , originally designed by Grammont and Baulot, improved shoulder pain and range of motion in patients with rotator cuff tear joint disease . In clinical applications, numerous studies have also demonstrated RTSA's effectiveness . With the rapid development of RTSA, its indications have gradually expanded to include various serious shoulder joint diseases such as acute complex proximal humeral fractures and old shoulder dislocations that cannot be reduced. Nowadays, RTSA has become the preferred treatment option for large, irreparable rotator cuff tears, as it can effectively alleviate shoulder joint pain and improve function. However, its relatively high incidence of postoperative complications remains a key focus for all clinicians. At present, the mainstream prostheses used in clinical practice are often designed and optimized based on the anatomical features of the scapula in European and American populations. However, these features differ across racial groups. A few studies have provided reference parameters for designing bases suitable for the Asian population and have indicated that the glenoid is smaller in Asians than in Europeans and Americans. Therefore, the use of traditional prostheses may lead to a mismatch between the prosthesis and the glenoid, which, in turn, causes scapular impingement and eventually results in loosening of the glenoid prosthesis. In addition, the contact area between the base and the bone surface is an important factor affecting the prosthesis's survival rate. Currently, many types of prostheses are available for clinical selection, and the contact area between the base and the glenoid varies among them. Accurate understanding of the fine anatomical characteristics of the glenoid in the Asian population is crucial for ensuring the correct selection and precise fixation of prostheses and for reducing the risk of surgical complications. 2D-CT scanning image measurement has been widely used in morphological research on shoulder joints, with good methodological consistency and population comparability. Compared with other measurement methods, it is more convenient to operate and is suitable for large-scale population studies in the future. Secondly, the two-dimensional cross-section can clearly display bony markers, facilitating standardized measurement and ensuring high stability and reliability. In addition, this study focuses on analyzing the bony geometric characteristics, and two-dimensional measurements are sufficient to meet the research requirements. Therefore, in this study, we retrospectively used 2D-CT images of the glenoid from 142 Asian populations for anatomical measurements and combined 3D-CT images to measure several anatomical indicators.

To provide references and design ideas for the optimization of reverse total shoulder (RTS) prosthesis design suitable for the Asian population by measuring the anatomical structural-related data of the glenoid in the Asian population and comparing the differences between them and the European and American populations.

A retrospective analysis was conducted on the unilateral shoulder joint imaging data of 142 healthy adults who underwent 2D-CT scans of the shoulder joint in the Department of Imaging of the Affiliated Hospital of Nanjing University of Chinese Medicine from January 2021 to July 2023. Among them, 60 were male, and 82 were female. The height, width, posterior inclination Angle, upward inclination Angle, axial and coronal curvature radii of the glenoid were measured through three-dimensional reconstruction and image archiving and communication system (PACS) . Statistical analysis was conducted using SPSS (version 26.0) , and the results were compared with those of previous research on the anatomical measurements of the scapula and scapular glenoid in European and American populations over the past 5 years.

The width (29.13±2.23) mm and height (36.66±2.81) mm of the glenoid in males were both greater than those in females (25.02±2.14 ) mm, (32.73±2.57) mm, with significant differences (P <0.001) ; The glenoid retroversion Angle in males was 3.10 (1.90, 5.23) °, and that in females was 1.85 (0.62, 4.10) °, with a significant difference (P <0.001) . The superior inclination Angle was 11.50 (7.58, 13.00) ° for males and 9.65 (6.15, 14.20) ° for females. There was no significant difference between the genders (P >0.05) . The axial curvature radii of males and females were 32.35 (26.53, 38.30) mm and 35.70 (27.80, 43.15) mm, respectively, and there was significant difference between the genders (P <0.05) . The average coronal curvature radii of males and females were 28.95 (26.90, 31.68) mm and 27.45 (25.05, 29.45) mm, respectively, and there was significant difference between the genders (P <0.05) . Correlation analysis showed that the size of the glenoid was positively correlated with gender, height, and weight (P <0.001) .

Compared with the previously reported anatomical data of the glenoid in European and American populations, the glenoid size and curvature radius of the Asian population are smaller. The curved base may be more conducive to fitting the articular surface morphology of the Asian population, with relatively small glenoid and a smaller curvature radius, thereby theoretically improving the matching between the base and the bone surface and optimizing the initial mechanical environment. For elderly patients with small glenoids or limited bone mass, this design may have potential application value. However, its specific impact on contact area, bone resection volume, and long-term fixation effect still needs further research to verify.