A numerical model to reproduce an experimental design to detect strain in cement

An experimental set-up consisting of a loading device inserted in a μCT scanner was numerically simulated to predict the strain at the bone-implant interface of the scapula after applying various loading conditions. The aim of the project was to determine which applied force is required to induce strain measurable by the μCT scanner. First, a 3D model of the bone was obtained by scanning a cadaveric scapula using CT scanner. Second, cortical and trabecular bone were segmented according to Hounsfield Units using Amira software. Extracted 3D scapula was assembled with a glenoid implant and cement and was cut to fit into the loading device. Final, a finite element model was created using Abaqus software. A mesh convergence study was undertaken to set the local element size to 2 mm around the peri-implant area. Strain – volume distribution in the cement was investigated. For an axial loading of 2.4 kN, 60% of the volume achieved a maximum principal strain value lying between 0.15% - 0.29% strain. Previous studies on DVC approach showed strain errors of 6 to 8 με. Such a low error percentage would be suitable for this study and hence the strain level should be detectable.