Although arthroscopic Bankart repair is commonly performed for recurrent anterior shoulder instability, it is associated with high redislocation rates in collision/contact athletes and patients with glenoid bone loss [[1], [2], [3]]. Good clinical results of coracoid process transfer, such as the Bristow [4] and Latarjet [5] procedures, have been reported for these patients. Coracoid process transfer involves transfer of the coracoid bone with its attached conjoint tendon to the anteroinferior glenoid. Stability is provided by glenoid surface augmentation of the bone graft, the sling effect of the transplanted conjoint tendon, and tension produced within the lower half of the subscapularis [6,7].

However, osteolysis of the transferred coracoid bone graft after the Latarjet procedure has recently been reported. Some authors have considered that severe coracoid bone graft osteolysis might induce recurrent instability or shoulder pain [8,9]. Haeni et al. [10] reported a reproducible method to quantify and compare coracoid bone graft osteolysis using three-dimensional computed tomography (3D-CT) after the arthroscopic Latarjet procedure. They found that the superior half of the coracoid bone graft undergoes significant osteolysis at 6 months postoperatively, potentially leading to future postoperative instability. By contrast, Tanaka et al. [11] reported several cases in which the surface area of the glenoid increased after the Bristow procedure as shown by two-dimensional CT. However, no reports have described measurement of the coracoid bone graft volume using 3D-CT after the Bristow procedure.

This study was performed to quantify the change in the coracoid bone graft volume as assessed by 3D-CT after the Bristow procedure. Additionally, we evaluated which part of the coracoid bone graft underwent morphological changes.