The ankle is one of the most injured joint in the body. However, it remains a new field of study in biomedical orthopedics. With the increased life span, more people suffer from arthosis and joint problems. That is why the improvements done in arthroplasty become important for the future. The goal of this project is to develop a numerical model for the ankle. This modelling will serve for future analysis, improvements for implants and developments of new prostheses. This model is build in two parts. First, a simple cylinder is considered instead of the talus for the finite elements analysis and then,another one with numerical representation of the tibia. This 3D representation is obtained by performing a segmentation on computer tomography scans. Both modellings will be tested in simulations with particular loading cases as the maximal force during gait or physiological load, as body weight. The outcome of this study leads to these conclusions. With the assumptions made in both modellings, the bone with the implant resists to the applied physiological loads. However, The model with the tibia needs more improvements in order to be more realistic, as inhomogeneous properties for bone tissue instead of the homogeneous ones or quadratic meshing definition. This model needs to be increased by adding the other components of ankle after the arthroplasty; that means the talus, its implant and the polyethylene part. The relations between the parts and the materials for the entire model of the ankle can be constructed based on the outcome of this project.