Related Experiment Video
Updated: May 30, 2026
Reverse Total Shoulder Arthroplasty
Published on: July 5, 2011
Does glenoid baseplate geometry affect its fixation in reverse shoulder arthroplasty?
Jaison James1, Kayla R Huffman, Frederick W Werner
1Department of Orthopedic Surgery, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
Background:
The effect of glenoid baseplate geometry has not been studied as it pertains to reverse shoulder arthroplasty. The purpose of this study was to compare 2 baseplate designs whose major difference is being either a flat backed design or a convex baseplate, with regard to their bone interface area, screw engagement, and bone volume removed using 3-dimensional modeling.
Methods:
Three-dimensional models of 6 scapulae were used to virtually implant models of a flat backed and a convex backed glenoid baseplate. Additional reaming was performed in 1 mm increments, up to 5 mm, and the amount of baseplate screw engagement was calculated at each increment. Statistical differences between flat and convex implants were calculated.
Results:
Insertion of the convex baseplate required statistically greater removal of bone as compared to the flat baseplate (P = .003). No statistical changes in total area were observed with reaming of the glenoid for the convex baseplate (P > .095). However, for the flat baseplate, 1 mm of reaming caused a statistical decrease in area available for fixation. The amount of total bone area in contact with a convex baseplate was statistically greater than with a flat baseplate (P = .004). The amount of screw engagement was statistically less with the convex baseplate, compared to the flat (P = .026).
Discussion:
A convex backed glenoid baseplate can improve the contact surface area at the bone implant interface as compared to a flat backed design. However, better screw engagement and less bone volume removed during reaming favors a flat backed design, particularly when adequate bone-implant contact cannot be achieved.
