Influence of inferior glenoid version and glenoid index on recurrent anterior shoulder dislocation

Recent studies have suggested a possible association between glenoid morphometric measurements and recurrent anterior shoulder dislocation, though the evidence remains inconclusive due to conflicting findings. This study investigates the relationship between various glenoid parameters in a normal population and compares them with measurements in patients with established recurrent shoulder dislocation. This study hypothesizes that glenoid version, inclination, and index are independent risk factors for anterior shoulder instability.

Data from 100 patients with recurrent anterior shoulder dislocation (study group) were compared with that of 116 matched patients (control group) who attended the hospital and underwent a Computed Tomography scan of the shoulder without any history of shoulder pathology.

The mean version at inferior glenoid in the dislocation group was +1.68° (-9.5 to 12.9) and in controls was -0.25° (-8.5 to 9.2), the value was statistically significant with P value <.01. Relative version at inferior glenoid with respect to middle glenoid was +2.96° (-1.8 to 7.6) in cases and +0.18° (-4.8 to 4.9) in controls, the value was statistically significant with P value <.01. The average glenoid index values were 1.58 (1.49 to 1.70) in cases and 1.52 (1.40 to 1.61) in controls, and the values were found to be statistically significant with P value <.01. Mean superior glenoid inclination was higher in cases (10.49) as compared to controls (9.76); the difference in means was not statistically significant.

We conclude that increased inferior glenoid anteversion and a higher glenoid index are significantly associated with anterior shoulder instability.