Finite element analysis on Sander III calcaneal fractures fixed by crossing screws or steel plate / 医用生物力学

ABSTRACT

Objective To make comparative study on the immediate stability of intra-articular calcaneal fractures fixed by crossing screws and by plate. Methods A set of foot CT images from a normal male were collected to construct 3D finite element models of Scander-III calcaneau fracture fixed by crossing screws and by steel plate, respectively. The regular pattern of stress and displacement distributions on these two fracture models under vertical load of 700 N was analyzed. Results For the screw-fixed model, the stress was concentrated at the connecting area between screws and fracture ends, and the maximum stresses were different for screws at different places. While for the plate-fixed model, the stress was concentrated at the connecting area between plate and screw. The highest stress was concentrated in anterior segment of the plate. The maximum stresses of plate, screw and calcaneus were all lower than their shear strength. The displacements of intact calcaneus and fractures were concentrated on the posterior subtalar joints, and a larger displacement appeared on the internal part of joint facet. Conclusions Both crossing screws and steel plate can be used to fix calcaneal fractures with a preferable initial stability. Functional exercise and rehabilitation are recommended at early time after operation.