Related factors for coracoid nonunion in the treatment of traumatic anterior shoulder instability with arthroscopic Bankart repair and open Bristow procedure.

Background: Arthroscopic Bankart repair alone has a high recurrence rate (40%-60%) in athletes with anterior shoulder instability. Combining it with the open Bristow procedure improves stability, but coracoid nonunion can lead to poor outcomes. This study examined factors related to coracoid nonunion in combined arthroscopic Bankart repair and coracoid transfer. Methods: This study included contact sports athletes who underwent combined arthroscopic Bankart repair and open Bristow procedure since 2014, with at least 2 years of follow-up. Patient data and pre-operative/post-operative computed tomography scans assessed coracoid fragment height, glenoid fixation distance, location of the transferred coracoid, screw angle, and surface contact with the anterior glenoid surface. Bone union was evaluated using radiographs at 6 months post-operatively. Univariate analysis and multivariate logistic regression analysis identified factors associated with nonunion, with cutoff values calculated. Results: In total, 212 shoulders in 210 patients were included in this study. There were 196 union cases, 16 nonunion cases, and 2 redislocations, both in nonunion cases. Nonunion cases had significantly higher coracoid fragment height (12.9 mm vs. 11.1 mm, Conclusion: Greater coracoid fragment height and a larger ratio to glenoid fixation distance were significant factors associated with coracoid nonunion in the combined arthroscopic Bankart repair and open Bristow procedure. Intraoperative considerations of coracoid size and the distance of the screw length may help prevent nonunion.