Development of a Finite Element Analysis Workflow for Studying Reverse Total Shoulder Arthroplasty

Abstract

The primary articulation of the shoulder joint is a multi-axis synovial ball and socket joint. By having a loose connection, it provides a wide range of motion; however, this means the joint lacks robustness and is prone to damage most commonly from shoulder dislocations. Rotator cuff tears also cause major problems by limiting the ability to lift the arm into abduction positions. It is common that this insufficiency aggravates arthritis within the shoulder. The study focuses on methods for investigating, describing and quantifying the effects of implant geometric properties on fixation and contact mechanics for a reverse total shoulder arthroplasty implant. The investigation presents the result of finite element analyses under heavy loading condition on a reverse shoulder implant. These finite element results are validated through comparison to experimental data on the same prosthesis. The implant is modelled using MIMICS (Materialise, Leuven, BE) and imported into SolidWorks and then ABAQUS (Simulia, Providence, USA) to analyse the distribution of displacement across the scapula. Details of interaction, boundary conditions, loads and material properties are all obtained from research and applied to the model to portray realistic behavior. The micromotion displacements of the implant were observed in the current study. The models follow the expected trends of the mechanics and what was seen in the experimental data and thus the modeling workflow makes sense overall. This can help to demonstrate the differences between different surgical options (e.g. various reverse implant designs), which may provide a basis from which improved designs can be built and allow more accurate methods to be developed in analyzing shoulder implant effectiveness. However, the method presented here needs further refinement to calibrate the models before it could be utilized in order to answer clinical questions.