LAUSR

In the present work, several mechanisms of four bars for knee prosthesis were studied and evaluated. We compared and defined the design parameters as well as an optimization method in terms of their stability and voluntary control to get a new mechanism. Few methods have been published to compare the performance and design parameters of the wide variety of polycentric knee mechanisms. In this work, we developed a method for performance comparison of polycentric knee mechanisms and designing a stable and novel four-bar mechanism with a voluntary control configuration. We defined design parameters for the optimization of a stable knee mechanism with voluntary control, presented a new dimensional design that can be functional for transfemoral users with different anthropometric characteristics and contributed with a simple method to obtain a mechanism with optimal sizing. A comparison of dimensional parameters of several mechanisms of knee prosthesis was obtained. There is the proposal of a new optimized mechanical configuration for assuring the voluntary control and a stable trajectory of the knee mechanism. With this method, it is possible to compare and design personalized mechanisms. Clinical relevance This method proposes a simple way to evaluate polycentric knees, and it is easy to use to compare and design stable mechanisms with voluntary control for transfemoral users with personal design parameters, if required.