Total knee replacement (TKR) is one of the most expensive prosthesis surgery, causing large costs to European countries. In Europe, an average of 107 knee prostheses per 100.000 inhabitants was needed in 2008. This means that approximately 335.000 knee prostheses are needed, considering that EuroArea (16 countries) has over 330 M inhabitants. This number is in constant increment in European countries and it is estimated that the global number will double each year. For instance, in UK the increment was 112% last year. Regarding the costs, the knee prosthesis is one of the more expensive. In France, the average cost of a knee prosthesis surgery was 11.000 euros last year. Thus, in the EuroArea it is estimated a global cost of around 3883 M euros per year. In the United States the situation is even more dramatic: an average of 500.000 knee prostheses are used each year.

Most of knee prostheses are designed and fabricated according to high quality standards and several research groups world-wide are actively working in the subject, mainly in USA and Japan. However, knee prostheses are usually affected by several factors, causing their loosening or fracture and then, shortening their long-term lifespan. This project address the enhancement of these designs by analyzing in deep engineering and medical factors such as: fatigue, wear, bone loss of density, etc. Finite Element Analysis (FEA) will be used to study the behavior and performance of existing designs, including nonlinear stress analysis and the effect of “stress-shielding”. Exhaustive comparative analyses will be performed to assess the behavior of several different geometries of the prostheses, thus allowing to make relevant changes both in geometry and prosthesis alignment, driven by the stresses gradients around the interface bone-prosthesis. It is well known that small variations in the geometry of the prosthesis can lead to an increment (or decrement) of the wear and, thus to reduce (or increment) the prosthesis lifespan. As well, the geometry of the prosthesis stem (tibial component) is crucial for the coupling bone-prosthesis, because the stresses levels at this interface can generate bone reabsorption. The main goal is to propose new (or modified) geometries for the knee prostheses in order to improve their performance and the enlargement of their long-term lifespan.