Finite element analysis of orthopaedic plates and screws to reduce the effects of stress shielding

Abstract

The biological adaptation of bone to changes in its environment is a continual process known as bone remodeling. Although it has been well observed that mechanical stimuli are required to initiate the bone remodeling response, the exact stimuli and mechanisms of this process remain unknown. When bone's normal level of mechanical stimuli is disrupted localized areas of bone experience changes in their rate of remodeling, (i.e. a rate of change in net bone mass and porosity). In the case of fracture healing with the use of fixation devices, a reduction in mechanical stimuli can lead to bone resorption. This phenomenon, known as stress shielding, is a common cause of failure in fracture fixation of long-bones. Using finite element models, this thesis studies the effects of implant geometry and material properties in relation to stress shielding, by examining bone-implant interactions of stress and also strain energy density distributions as possible mechanical stimuli.