A fuzzy logic model of fracture healing

A quantitative biomechanical model describes the tissue transformation duri ng healing of a transverse osteotomy of a sheep metatarsal. The model predi cts bridging of the bone ends through cartilage, followed by the growth of a callus cuff, and finally, the resorption of callus after ossification of the interfragmentary gap. We suggest bone density or the modulus of elastic ity do not sufficiently characterize healing tissue for predictive purposes . Tn addition to the stimulus reflected by strain energy density we introdu ce a new osteogenic factor based upon stress gradients and which predicts a reas of a high osteogenic capacity. Our model distinguishes three basic typ es of tissue, namely bone, cartilage and fibrous tissue. A fuzzy controller is proposed to model the tissue reaction. A set of fuzzy rules derived fro m medical knowledge has been implemented to describe tissue transformation such as intramembraneous or chondral ossification, atrophy or destruction. Fuzzy logic is able to model tissue transformation processes within the num erical simulation of remodeling processes. This approach improves the simul ation tools and affords the potential to optimize planning of animal experi ments and conduct parametric studies. (C) 2000 Published by Elsevier Scienc e Ltd. All rights reserved.