Can we use the contralateral glenoid cavity as a reference for the measurement of glenoid cavity bone loss in anterior shoulder instability?. A comparative analysis of 3D CT measurements in healthy subjects

Abstract

The purpose of this study was to compare the glenoid cavity measurements in healthy subjects. 100 adult subjects without shoulder pathology who had pulmonary computed tomography for any reason, were included in the study. Lung CT images were three-dimensionally rendered and glenoid cavity enface images were obtained. On these images, the glenoid cavity superior-inferior long axis and anterior-posterior equator, as well as the equatorial anterior and posterior radii, were measured. Dominant and non-dominant glenoid cavity measurements were compared using the t-test in dependent groups. The long axis of the dominant glenoid cavity was 38.15 +/- 3.5 mm, whereas it was 37.87 +/- 3.3 mm on the non-dominant side (p = 0.068). The mean width of the glenoid cavity was 28.60 +/- 3.3 mm in dominant glenoids cavities and 28.00 +/- 2.9 mm in the non-dominant side (p = 0.0001). The equatorial anterior and posterior radii were significantly different between the two sides (p = 0.010, p = 0.001, respectively). The ratio of length to equator was different between the two sides (p = 0.012). The difference in equatorial lengths was 0.98 +/- 0.8 mm (range, 0-4.2 mm). The mean difference between the long axis of the glenoid cavity was 1.2 +/- 0.9 mm (range 0-4.6 mm). The equator on 69 individuals was larger on the dominant side. Glenoid cavity long axis was larger on the dominant side of 61 individuals. Glenoids cavities are not equal and not symmetrical to each other or influenced by hand dominancy. Measurements based on the assumption that both glenoids cavities are equal may be misleading.