The fundamental mechanism of aseptic glenoid component loosening, the rocking horse phenomenon, is a reaction to glenohumeral articular forces that are not centered on the component. While glenoid component loosening remains a problem, the underlying mechanisms that lead to fixation failure at the bone-component contact remain controversial. Several studies employing the ASTM F2028 technique have successfully recreated the rocking horse effect. However, no obvious strategy to decrease component loosening has been presented. This thesis investigates the behavior of forces that lead to component loosening on cyclically loaded components using three different protocols and testing apparatuses—a Stewart Platform, a cyclic loading experimental rig, and an ASTM F2028-17-compliant version of the experimental rig. The experimental assessment of response forces acting on the glenoid implant is a desired outcome since it can be used to compare implant designs and allows for controlled testing of alternative materials for prosthesis advancement to lessen the stresses that produce the rocking horse phenomena.
Keywords:
Total Shoulder Arthroplasty; Glenoid Implant; Reaction Forces; Stewart Platform; Experimental Apparatus; Rocking Horse Phenomenon; Glenoid Loosening