Numerical modelling and experimental validation of canine endoprostheses with variable shapes

The goal of this thesis is the static analysis of canine endoprostheses under a specific tensile load, replicating the forces acting during a dog's gait. This analysis is based on a finite element model (FEM) and subsequently validated through experimental laboratory tests. For this reason, it is crucial to investigate the behavior of the prosthesis and the prosthesis-bone complex under specific loading conditions to assess whether the prosthesis design and material are suitable for its intended function or prone to failure or hazardous deformations. The introductory chapter examines the most prevalent skeletal disease affecting dogs, for which no standardized treatment has yet been established: osteosarcoma. This section provides an overview of current treatment approaches, including limb amputation, chemotherapy, and various limb-sparing surgical techniques. Among these techniques, particular attention is given to the use of endoprostheses, which are implanted following the surgical resection of the tumor. Three case studies have been analyzed in which researchers attempted to improve the design of canine endoprostheses for the radius. The first chapter focuses on the anatomy of the canine limb and the biomechanical analysis of movement, highlighting the forces exerted during both walking and trotting. Special attention is given to the magnitude of these forces and the joints primarily involved in their transmission. In the second chapter, finite element models (FEM) were created for each of the 11 provided canine prosthesis prototypes. Specifically, two models were developed for each prototype: a simpler model, referred to as Model 1, and a more detailed model, referred to as Model 2. Numerical simulations were performed for both models using the Ansys software. A tensile test was implemented to analyze the prosthesis's behavior under applied forces. The tests were conducted for two different force values in each case, allowing for the generation of a force-displacement graph based on the numerical simulation results. The third chapter focuses on the experimental tests conducted in the laboratory, where physical models of the 11 prototypes were subjected to tensile testing using a dedicated testing machine. The results collected during these tests are presented. For each model, a force-displacement graph was plotted, and the breaking point of the specimen was recorded. Finally, in the last chapter, a sensitivity analysis of both models was conducted and a critical comparison was performed between the numerical simulation results and the experimental laboratory results to validate the designed finite element model.