The paper is intended to analyze the design of circular external fixation system for bone union. It is a fixator system where threaded pins are anchored in the bone. These pins pass through the cortex on either side of the medullary space, and only a few ‘mm’ of the pin tip should protrudes through the distal cortex. The usual complications of this fixation system are loosening of the pins. These pins deform and in-turn distorts the bone. To avoid the stress on the bone, the fixation technique is analyzed and the mechanical behaviour of the circular fixation device is studied. The angle between the pins in a circular fixator is usually 90º. The stresses related in the present fixation and the stress after redesign are to be studied. The fixator is designed using Pro-E and analyzed using ANSYS. © 2018 Elsevier B.V., All rights reserved.