Comparative Analysis of Eccentric Glenosphere in Reverse Total Shoulder Arthroplasty: A Computer Simulation Study

Xiaopei Xu; Qingnan Sun; Yang Liu; Dong Wang; Shuo Diao; Hanzhou Wang; Yuling Gao; Tianchao Lu; Junlin Zhou

doi:10.2147/IJGM.S426191

Comparative Analysis of Eccentric Glenosphere in Reverse Total Shoulder Arthroplasty: A Computer Simulation Study

Int J Gen Med. 2023 Oct 17:16:4691-4704. doi: 10.2147/IJGM.S426191. eCollection 2023.

Authors

Xiaopei Xu¹, Qingnan Sun¹, Yang Liu¹, Dong Wang¹, Shuo Diao¹, Hanzhou Wang¹, Yuling Gao¹, Tianchao Lu¹, Junlin Zhou¹

Affiliation

¹ Department of Orthopedic Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, People's Republic of China.

Abstract

Objective: The aim was to evaluate the effects of different glenosphere eccentricities on impingement, range of motion (ROM), and muscle length during standard activities in reverse total shoulder arthroplasty (RSA).

Methods: In this study, we utilized computational modeling techniques to create native shoulder and shoulder models undergoing RSA and simulate shoulder movements in all abduction-adduction, flexion-extension, and rotation. We tested a total of 36 different glenosphere configurations, which included three different inferior tilts (0°, +10°, +20°) and two different lateral offsets (0 mm and +4 mm), as well as six different glenosphere eccentricities (concentricity, inferior, posterior, anterior, anteroinferior, and posteroinferior). We evaluated the maximum impingement-free ROM, impingement sites, and muscle lengths.

Results: All glenosphere configurations exceeded 50% of native shoulder ROM in three planes and total global ROM. In abduction-adduction, there was no significant difference among the different glenosphere eccentricities (p > 0.05). In flexion-extension, the posteroinferior eccentricity had the maximum ROM among the different eccentricities, but no significant difference among the different glenosphere eccentricities (p > 0.05). In rotation, there was a significant difference overall, and anteroinferior eccentricity had a significant advantage over concentricity (p < 0.05). In total global ROM, anteroinferior eccentricity had a significant advantage over concentricity when lateral offset was 0 mm (p < 0.05). In all models of glenosphere eccentricities, only the elongation of the infraspinatus muscle was statistically significant (p < 0.05).

Conclusion: Glenosphere eccentricity significantly influenced rotation, total global ROM, and the length of the subscapularis muscle. Among them, anteroinferior offset achieved the maximum ROM in abduction-adduction, rotation, and total global activities. Both anteroinferior and inferior glenoid eccentricity showed significant advantages over the concentricity in rotation and total global ROM.

Level of evidence: Basic Science Study; Computer Modeling.

Keywords: glenosphere eccentricities; impingement; muscle length; notching; range of motion; reverse shoulder arthroplasty.

Grants and funding

The correspondence author Junlin Zhou discloses receipt of the following financial support for the research, authorship, and publication of this article: National Natural Science Foundation of China (82272469), Beijing Key Clinical Specialty Project and Haidian Original Innovation Joint Fund of Beijing Natural Science Foundation (L212009).