Functional assessment of a surgical robot for reduction of lower limb fractures

Background This paper presents a novel robot designed for reduction of lower limb fractures, with the additional features of automatic controlled flexion of the knee joint, individual traction of thigh and leg, and foot rotation. The aim of this design is to assist the orthopaedic surgeon to perform better fracture reduction through motor control, in contrast to current manual control, and the results of assessments of its functions on normal subjects are presented in this paper. Methods The robot was designed to be mounted onto the operation table, and was controlled through open switch relay. Functional assessments were conducted on six healthy volunteers in terms of knee joint motion and lower limb traction; measurement of angle and distance was calculated from data obtained by a 3D ultrasonic motion system (Zebris®). Results The results showed a good correlation of the flexion angle between the robot and the subjects at the knee joint. In the traction tests, a steady lengthening of the proximal as well as the distal segment of the robot was observed, and a slight increase in subjects' limb length was also recorded, which might be due to distraction in the joint space. Conclusion This automatic control fracture table has distinct features compared with the conventional ones, and it is believed to be of assistance to surgeons when performing fracture fixations.