Glenoid version and recurrent anterior shoulder dislocation: a case-control study

The contribution of glenoid version to anterior shoulder instability remains controversial, with prior studies reporting inconsistent results. This study aimed to determine whether CT-measured glenoid version differs across lesion patterns and whether increased anteversion is associated with recurrent anterior dislocation.

This retrospective case-control study included 214 patients with traumatic anterior shoulder instability and 104 controls without instability. All subjects underwent standardized axial CT imaging. Glenoid version was measured using the Friedman method by three independent observers, and interobserver reliability was assessed using the intraclass correlation coefficient (ICC). Instability cases were classified as isolated Bankart or Bankart + Hill-Sachs. Group comparisons were performed, and correlations between glenoid version and dislocation frequency were analyzed.

Glenoid version differed significantly among the three groups (p < 0.001). The control group demonstrated a mean version of - 4.12°, compared with - 1.06° in the isolated Bankart group and - 1.01° in the Bankart + Hill-Sachs group. Patients with recurrent dislocations exhibited markedly more anteverted glenoid orientation than those with a single event (0.47° ± 3.26° vs. - 5.30° ± 1.77°, p < 0.001). A strong positive correlation was observed between the number of dislocations and glenoid version (r = 0.654, p < 0.001). Interobserver agreement was excellent (ICC = 0.995).

Increased anterior glenoid version is significantly associated with recurrent anterior shoulder instability. Although version alone does not account for the multifactorial nature of instability, it may serve as a complementary anatomical parameter in future clinical risk-stratification models.