Investigate Axial Dynamization Movement by Using Genetic Algorithm Method Based on a Unilateral External Fixator

Unilateral external fixators are commonly used to stabilize the fractured tibia bone. Compared with static fixation, axial dynamic motion can be used for promoting callus formation, improving bone healing at fracture sites. Moreover, non-axial motions are not conductive to promoting bone healing and remodeling. However, a fixator-bone system with 7(DOFs) can not achieve both fracture correction and axial dynamic motion. Maybe it is easy to think that this problem could be solved by adding one DOF for fixator structure. However the increased structural flexibility could not be able to meet the demands of lower cost and size, and higher stiffness. Thus, how a fixator-bone system with 7 DOFs not only can realize fracture correction, but also complete axial dynamic motion as far as possible. So far, researchers have never solved this problem. Therefore, we establish a mathematical model based on the 7 DOFs Orthofix fixators, and try to use the genetic algorithm method to reduce the tangential displacements in the process of axial dynamization after fracture correction. The results suggest that the use of genetic optimization algorithm can effectively reduce tangential displacement. This study helps facilitate appropriate and flexibility application of fixators to better control axial dynamic motion and decrease tangential displacements.