Osteoarthritis is the most common kind of rheumatoid arthritis and is characterized by articular cartilage's damage. The principal risk factors leading to osteoarthritis build up in the knee are overweight, articular overload and congenital problems. When osteoarthritis is severe, knee joints present a deficient biomechanical behaviour that limits their movement and a total knee replacement (TKR) is often necessary. Nowadays, 70% of Mexicans are overweight so, they have a high probability to develop osteoarthritis of the knee. In order to satisfy the future demand for TKR in Mexico, five total knee replacement models have been designed at the Instituto Tecnologico de Celaya (ITC)

Mathematical models and finite element analyses have shown to be efficient methods to evaluate the mechanical and clinical performance of knee implants during the design phase. Contact stresses' study is very important because if stresses are excessive may lead to delamination of the UHMWPE components.

 The aim of this work was to perform three-dimensional implicit transient finite element analyses to determine the best mechanical device among five total knee replacements designed in the Institute (TKR-ITCx). The boundary conditions and loads applied to the models reproduced the mechanical environment existing in the Knee Simulator built in the Institute (KS-ITC). Our findings revealed that model TKR-ITC4 presented the lowest level of contact stresses so, its useful life will be the longest.