Semi-automatic percutaneous reduction of intra-articular joint fractures - An initial analysis

Robot-assisted orthopaedic surgery has proved to provide better outcomes over conventional surgery in terms of improved spatial accuracy and more reliable and repeatable results. We present a novel use of robots in orthopaedic surgery - precise anatomic reduction of joints´ fractures. The joints of the body are frequently involved in bone breaks, typically classified as intra-articular fractures. If a joint is to function properly again, that is to provide pain-free stability and movement, the broken pieces of the joint must be subjected to an anatomic reduction - being put back together as perfectly as possible. Having minimally invasive, closed anatomic reduction as a starting point, our method involves a rigorous surgical workflow analysis to create a general framework for robotic reduction techniques. Small and lightweight spatial parallel manipulators are utilized in this pilot study to move fragments through pre-calculated trajectories. In this paper, our initial analysis of clinical and functional requirements of a robot-assisted joint surgery is presented, followed by description of a developed physical robotic system for minimally invasive joint surgery. Experimental results show that a simple graphical user interface is sufficient to obtain the transformation parameters to position fragments in space. The fragment manipulating devices can position and align fragments with an accuracy of ±1mm and ±5degress.