Design of a new tibial intramedullary nail

Abstract

Aim of this work is designing a new intramedullary nail able to reduce the drawbacks of the distal locking, ensuring the axial stability, so enabling a speedy recovery of the fracture and a time-reduced immobilization of the limb. During the first phases of the design process, the parametric CAD model has been carried out and, successively, several numerical analyses have been set up to verify the nail behaviour under the usual post-operation loading conditions. In particular, non linear FEM analyses have been performed to define the right nail positioning, the average and maximum values of stress and contact pressure, and the stability of the joining by means of the new nail. The obtained results have shown a not uniform contact pressure distribution at the nail-tibia interface due to the irregularity of the inner surfaces of the tibia. Moreover, no longitudinal or rotational sliding has been observed during the numerical simulations, then demonstrating the effectiveness of the distal locking by the expansion of the flanges nail. The new designed nail, besides simplifying the distal locking procedure and reducing the operation time, it is able to assure a reliable distal fixation and ensuring the stability of the system.