[Analysis of stress in the knee using the finite element method]

The increase in the number of the studies of the stress around the anatomic prosthesis by the finite element method incited the authors' work. Our purpose was to study the methodology of a technic with simple cases. The finite element method is a method of calculation which allow the calculation of the displacement under the stresses of each element that we created in the structure. Before this calculation, we needed to define the exact geometry of the structure, the elementary properties of the material and the conditions of the experimentation, particularly the strains that exist in the structure. Three simple examples are given: an osteosynthesis plate with an hole, a knee model that Maquet studied with the photoelasticimetry method and a bidimensional knee model. The results are traduced by different colours or by coloured ligns. The conclusion is to warn the orthopaedic surgeons to look carefully what model is behind the pretty coloured results.