A fractured metacarpal joined with a poly L lactide acid device is studied analyzing its performance under different kinds of loads and studying them in a finite element analysis software.The metacarpal and polymer devices are designed in a computer aided design software.Relaxation and tensile performance of the polymer are determined.Then, we developed a rheological model.The rheological model is simulated and the chosen model with two Neo-Hookean networks in a parallel distribution lead to a fit of 98 %.Flexural and tensile performance of the assembly is depicted.The Von Mises stress is used as way to determine the correct performance of assembly.After the analysis, the holes in the bone is the main cause of failure in this fixation method because of the stress associated with accumulation of stress owing to change in geometry.Additionally, the use of finite element analysis reduces resources and destructive tests can be avoided.Furthermore, a mathematical model of the mechanical behavior of the poly-L-lactide acid is achieved using a Parallel Network Model.