Finite element study of some parameters of bone fractures fixed with screws

Abstract

In case of fracture of the neck of the femur a common way of successful rehabilitation of the injured is osteosynthesis. An essential condition of successful recovery is the enhancement of the stability of the fixation of fractures. However, at old age the layer of spongiosa becomes so porous that the threads of screws used for the treatment of the fracture of the neck of the femur virtually fulfil their fixing function only in the subchondral region - less and less in the inner layer of the spongiosa. However, in the subchondral region, the outer layer of 4 to 5 mm remains relatively dense. To increase stability, we modified the traditionally - shaped canulated screws, used for the neck of the femur to date, and developed duplex-threaded screws for the neck of the femur, submitted for a patent as well. By finite element calculations, we would like to verify the effect of stress and geometric parameters - playing an important role in the stability of fixation - for both types of screws for the neck of the femur.