JSES International (Nov 2024)
Three-dimensional glenohumeral relationship in cuff tear arthropathy and its correlation with the type of cuff tear
Abstract
Objective: The main purpose of this study is to evaluate 1) the three-dimensional (3D) glenohumeral relationship in cuff tear arthropathy (CTA) and 2) the correlation between different types of rotator cuff tears (RCTs) and the 3D glenohumeral relationship. Method: A total of 124 patients with CTA and 60 control patients were included in this study. 3D models of computed tomography images of the shoulder were reconstructed to evaluate the position of the humerus in relation to the scapula using a Cartesian coordinate system. The glenohumeral relationship of the CTA group is compared to the control group (group N). Next, the CTA group is divided into three subgroups depending on the (im)balance of the transverse force couple (TFC): a balanced RCT group (group B, n = 50), a group with an imbalance of the TFC to anterior (group A, n = 30), and a group with an imbalance of the TFC to posterior (group P, n = 44). The glenohumeral relationship of the RCT group is compared to a control group of 60 patients without RCT (group N). Results: The CTA group (96° ± 1°) was significant (P < .05) and more superiorly subluxated than the control group (88° ± 1°). There was no significant difference in the superior subluxation between the three subgroups: group A (98° ± 3°), group P (96° ± 3°), and group B (97° ± 2°). Group A (88° ± 2°) showed significantly more anterior subluxation compared to group P (92° ± 1°). Conclusion: All patients with CTA have a significantly superior position of the humerus compared to the control group. If the TFC is unbalanced, a significantly more anterior or posterior translation of the humerus is observed depending on the direction of the imbalance.
