Bone-remodeling of lower-leg or foot for orthopedic osteotomy with external fixators

Although Ilizarov technique and external fixators have been popular applied in bone fractures and orthopaedic surgery currently, there are few literatures about laws of bone-remodelling after osteotomy when applied external fixation system based on Wolff´s law. However, Wolff´s law is one of the most basic theories in bone biomechanics and fracture healing Therefore, exploring the healing mechanism of broken bone under the function of external fixators may be a key role in achieving new breakthroughs of this technology. In this study, we built the mechanical model based on lower-leg or foot. Then, bone-remodelling algorithm of lower-leg or foot for orthopaedic osteotomy with external fixation system under the guidance of Wolff´s law was proposed. Through numerical simulations, the following findings were achieved: (1) the change of element density in loading position is mainly caused by the effect of `dead zone´, (2) the magnitude of loads directly influences bone mass and the location of wire component in external fixation system greatly affects distribution of bone density in the process of bone-remodelling, (3) the strain energy density tends to be uniformly distributed when reaching the remodelling equilibrium state.