Exploring Alternative Sites for Glenoid Component Fixation Through Three-Dimensional Digitization of the Glenoid Vault: An Anatomic Analysis.

Abstract

Glenoid component loosening has remained one of the most common complications for total shoulder arthroplasty. Three-dimensional modeling of the glenoid may reveal novel information regarding glenoid vault morphology, providing a foundation for implant designs that possess the potential to extend the survivorship of the prosthesis. A three-dimensional digitizer was used to digitize the glenoids of 70 cadaveric scapulae. We identified ideal position, fit, and maximum diameter for cylinders of 5, 10, and 15 mm depths. Maximum diameter and volume were also measured at the glenoid center, and the data were compared. The vault region that accommodates the greatest diameter and volume for 5, 10, and 15 mm depth cylinders were identified in the postero-inferior glenoid. Across all specimens, this region accommodated a cylinder diameter that was 24.82%, 40.45%, and 50.34% greater than that achieved at the glenoid center for 5, 10, and 15 mm depth cylinders, respectively (all, P < 0.0001). The location of this site remains reliable for each cylinder depth, regardless of sex. This study presents novel findings pertaining to glenoid morphology through the analysis of a newly characterized glenoid vault region. This region has not been identified or described previously and has potential to serve as an alternative to the glenoid center for peg or baseplate fixation. Our method of vault analysis and findings may be used to guide further research regarding pathologic glenoid anatomy, providing a foundation for alternative approaches to glenoid prosthesis fixation in total shoulder arthroplasty and related procedures.