Background: Variations of morphology of the glenoid cavity have been previously reported. These influence the surgical reconstruction or arthroplasty of the shoulder. This study aims to study the variation of the shape of suprascapular notch, shape of glenoid cavity, dimensions of both the scapular and the glenoid cavity, and predict the glenoid dimensions from the scapular dimension parameters.
Materials and methods: Adult-dried scapulae were collected. The shapes of each suprascapular notch and glenoid cavity were evaluated. The scapular height, scapular width, glenoid superoinferior distance, and glenoid anteroposterior distance were measured using a digital vernier caliper, and statistical analysis was conducted on the data that were obtained.
Results: There were 264 scapulae included in this study (166 male and 98 female). Most of the glenoid cavities were pear shaped (69.7%). The two most common types of suprascapular notches were small depression notches (31.8%) and the absence of notches (25.8%). The mean ± SD of scapular height, scapular width, glenoid superoinferior distance, and glenoid anteroposterior distance were 148.2 ± 10.0, 108.1 ± 6.4, 37.1 ± 2.2, and 27.4 ± 2.1 mm, respectively, in the male samples and 133.0 ± 7.0, 97.0 ± 5.2, 33.2 ± 1.9, and 23.7 ± 1.7 mm, respectively, in the female samples. The male scapulae were significantly larger than the female scapulae (p value < 0.05). However, there were no differences between the male and female scapulae in terms of scapular index or glenoid index (p value > 0.05). Scapular height and width were significantly associated with both the glenoid superoinferior distance (p = 0.0001) and glenoid anteroposterior distance (p value = 0.0001).
Conclusion: Scapular height and width can predict the dimensions of the glenoid. In cases of glenoid bone loss or shoulder arthroplasty, the native normal glenoid dimensions can be determined from the scapular dimensions as visualized using a true scapular anteroposterior radiograph. The surgeon can use these preoperative parameters when performing glenoid reconstruction or shoulder arthroplasty.
Keywords: Dimension; Glenoid; Morphology; Scapula.