Conception et analyse de prothèse de hanche de type spacer

Abstract

This thesis focuses on the mechanical study of a temporary hip prosthesis, known as a spacer, used primarily in two-stage treatments for periprosthetic infections. Typically made of bone cement (PMMA), this type of implant exhibits low mechanical strength, which can compromise its stability and durability, particularly in the absence of internal reinforcements. In this context, the work aims to analyze and compare three configurations of spacer femoral stems : one without reinforcement, one with a cylindrical reinforcement, and one with a flat reinforcement. The approach adopted combines 3D geometric modeling using SolidWorks and mechanical simulation using the finite element method via Abaqus. The prosthesis is inserted into a bone environment composed of cancellous bone surrounded by cortical bone, modeled to faithfully reproduce anatomical reality. The applied stresses reproduce physiological forces, including axial load due to body weight and abductor muscle strength. The results are analyzed for several stress components (σXX, σYY, σZZ, σXY, σXZ, σYZ, and Von Mises) on the outer and inner surfaces of the stem, distinguishing three functional zones: proximal, medial, and distal. The analyses show that the unreinforced configuration generates high stresses, particularly in the proximal zone. The cylindrical reinforcement partially reduces these stresses, while the flat reinforcement allows for a significant improvement in force distribution and a significant reduction in critical stresses, particularly in tension and shear. This thesis thus demonstrates the importance of a reinforced spacer design to ensure its mechanical performance and clinical safety. It highlights the value of digital tools for optimizing the design of medical devices and paves the way for more robust temporary prostheses, possibly 3D printed or reinforced with composite structures.