Robot-assisted fracture reduction: A preliminary study in the femur shaft

Abstract

Reduction in femoral shaft fractures can be difficult to achieve with minimally invasive techniques. Malalignment and high intra-operative radiation exposure can result. The hypothesis was that robot-assisted fracture reduction could improve the quality of reduction while reducing the amount of radiation exposure. A robot system was developed that allows fracture manipulation with a joystick as input device. The system provides the surgeon with haptic and metric feedback. Fifteen synthetic femurs were broken and reduced by simulated open (group A) and closed techniques (group B). These techniques were compared with the robot-assisted reduction with (group C) and without (group D) haptic and metric information. An image intensifier was simulated with two orthogonal cameras. All reduction techniques showed minor malalignment. In group C, the alignment was: procurvatum/recurvatum 0.6 degrees (0-2.0 degrees); varus/valgus 0.8 degrees (0-3.0 degrees); and axial rotation 0.8 degrees (0-3.1 degrees). A significant difference was seen between the groups (two-way ANOVA, p < 0.001). Axial rotation was significantly lower in group C than in group B (1.9 degrees; p < 0.001). The residual varus and valgus deviation was higher in group C compared with group A (0.4 degrees, p = 0.03). The median number of simulated radiographs was significantly less in group C (35) compared with group D (72; p < 0.001) and group B (49; p = 0.01). Robot-assisted fracture reduction of the femur provides high precision in alignment while reducing the amount of intraoperative imaging. Further research in this field is worthwhile.

Forces and torques during fracture reduction: Intraoperative measurements in the femur

“…15,16,23 The only published robot-assisted fracture reduction was performed on artificial bones without any counteracting forces and torques. 23 For tests on cadavers or human beings, knowledge of the relevant reduction forces and torques is necessary. The load limit of the robot must exceed the reduction forces, and the device that fixes the robot to the bone has to withstand these reduction forces.…”

Telemanipulated Long Bone Fracture Reduction

“…The good results of these tests, with very high reduction accuracies and short operation times, encouraged the further development of this telemanipulated fracture reduction concept. Furthermore, this pilot study revealed the importance of haptic and metric information to the surgeon during the reduction process (Gösling et al, 2005;Westphal et al, 2003;Westphal et al, 2004). The next development step, was the telemanipulated reduction in a more realistic surgical environment.…”

Improving the human–robot interface for telemanipulated robotic long bone fracture reduction: Joystick device vs. haptic manipulator

“…20 We have previously developed a robotic framework for the treatment of femoral fractures. [21][22][23][24] The technique has the overall aim of improving reduction accuracy and of reducing the incidence of femoral malrotation. 21,25,26 Given that this system includes features of telemanipulated and hands-on robotic systems, 27 achieving a reliable and user-friendly human-robot interface is an important part of this project.…”