Comparative Finite Element Analysis of Osseointegration System in Trans-Radial Amputation: A Proposal of New Design

Abstract

Introduction: Conventional osseointegration systems have been applied in patients requiring trans-humeral and trans-femoral amputations. However, the application of these systems to trans-radial amputations is limited by the small diameter of the radius and ulna. Our study aimed to compare the biomechanical stability of a novel osseointegration system with that of a conventional system used in trans-radial amputations using a finite element(FE) models.Methods: We established three-dimensional FE models of trans-radial amputations, which were osseointegrated with both the novel and conventional systems. External loads were applied to the FE models with compressive force and tensile force along the long axis, horizontal shear force, and vertical shear force. The maximum equivalent stress(MES) and the distribution of stress through the radius and ulna was evaluated.Results : The MES of the radius and ulna was higher in the conventional system when compressive, tensile, and vertical shear forces were applied. However, when the horizontal shear force was applied, the opposite result was found. The distribution of stress was more effective in the novel system.Conclusion : Three-dimensional FE modeling showed that the novel system enables to have a lower stress level and a more even distribution of stress for osseointegration in trans-radial amputations.