A model to predict the incidence of fracture in femoral components.

The paper presents a probability model for the fracture of femoral components based on the assumption that the components are defect-free, and that they fracture by a fatigue process. The model predicts the probability of fracture for patients of different body weight, and the incidence of fractures versus body weight, and versus time. The results are compared with recently published survey data. In addition the model is used to demonstrate the effect of improvements in the mechanical properties of components. Finally the paper discusses the modifications needed to demonstrate the effect of variations in component design, prosthesis orientation, and level of patient activity, and the effect of time-dependent processes such as bone resorption, acrylic disintegration and shock loads.