Axial fatigue performance of medical screws in synthetic bone

Abstract

This paper investigates the axial fatigue performance of self–tapping medical screws in synthetic bone joints. The effect of loading amplitude and screw implant depth on fatigue behaviour of the bone screws is explored. The study also provides an experimental investigation of stiffness degradation of a self–tapped bio–joint system under cyclic axial loading. Results on the failure behaviour and axial fatigue performance of medical self–tapping screws are discussed. The results show higher screw implant depth yields lower displacement amplitude change and screw stiffness degradation rate in fatigue. Linear relationships between the logarithms of fatigue life and peak cyclic load as well as between screw axial stiffness and mean displacement (progressive displacement) are explored.