Structural Design and Performance Evaluation of a Novel Reduction Robot for Long-Bone Fractures

Abstract

Abstract Long-bone fractures are common complaints in orthopedic surgery. In recent years, significant progress has been made in robot-assisted fracture-reduction techniques. As a key medical device for diverse fracture morphologies and sites, the design of the reduction robot has a profound impact on the reduction outcomes. However, existing reduction robots have practical limitations and cannot simultaneously satisfy clinical requirements in terms of workspace, force/torque, and structural stiffness. To overcome these problems, we first analyze the potential placement areas and performance requirements of reduction robots according to clinical application scenarios. Subsequently, a 3U P S/S-3 P hybrid configuration with decoupled rotational and translational degrees of freedom (DOFs) is proposed, and a kinematic model is derived to achieve the motion characteristics of the remote center of motion (RCM). Furthermore, the structural design of a hybrid reduction robot with an integrated distal clamp and proximal fixator was completed, and a mechanical prototype was constructed. The results of the performance evaluations and static analysis demonstrate that the proposed reduction robot has acceptable workspace, force, and torque performance and excellent structural stiffness. Two clinical case simulations further demonstrated the clinical feasibility of the robot. Finally, preliminary experiments on bone models demonstrated the potential effectiveness of the proposed reduction robot in lower-limb fracture reduction.