Exploring Methods for Improving Baseplate Fixation in Reverse Total Shoulder Arthroplasty
Abstract
Improving the success of modern reverse shoulder replacements is dependent on optimal initial baseplate fixation. A cadaveric biomechanical investigation examined how peripheral screw position and orientation affect baseplate fixation in normal glenoids. The results show no statistically significant difference between screw position (p=.60) or orientation (p=.20) regarding baseplate micromotion in the non-eroded glenoid. In a subsequent study to determine best management in pathologic baseplate fixation, a computer-model was employed to quantify the erosion in the E2 type glenoid. In the E2 type glenoid, erosion was found to be oriented postero-superiorly and covering an average of 66% of the surface area of the glenoid, requiring a full augmented baseplate for best seating. Overall, these findings support aiming peripheral screws into best quality bone. In the eroded E2 type glenoid, this is located postero-superiorly encompassing two-thirds of the glenoid’s surface and can be managed by dialing a full wedge augmented baseplate postero-superiorly.