Investigating the stability of motorized unilateral external bone fixators to recover the destroyed bones in dynamic mode using the finite element simulation

Nowadays, the alignment of broken bones using unilateral external fixators has been popular. However, their adjustment to hold bone pieces from four areas and move them by loosening the screws for ossification is associated with errors and consequently various problems. The present study aims to assess the stability and strength of a unilateral external fixator equipped with four motors, which is able to accurately move the bone pieces from four areas using the motors without error. The device is designed in SolidWorks software. Then, its simulations and analyzes are performed using the finite element method in ANSYS software. The results of the simulations in dynamic mode in a period of 1 s, compressive forces of 150 N and 130 N, and eight-point bending force of 150 N confirm the stability of the device and by applying a twisting torque of 8 Nm, the device still maintains its stability. The results show that the designed device has the necessary stability, rigidity, and strength to keep the bone stable. Moreover, using the electronic control unit of the motors, this device can precisely move the bone pieces for ossification. Therefore, it is recommended to manufacture and use this device in orthopedic surgeries.