Robotic-assisted knee arthroplasty has been clinically available for the past 2 decades, but is still in the early stages of adoption for use in total knee arthroplasty (TKA). The purpose of this technology is to improve the precision, accuracy, and reproducibility of TKA. Robotic-assisted systems may be passive, semiactive, or active. Although robotic-assisted systems have been used extensively in unicondylar knee arthroplasty, there are relatively few studies of using this technology in TKA. These early studies have shown that robot-assisted technology may lead to improvements in both mechanical axis and component alignment. No studies have demonstrated that these radiographic improvements have translated into any clinical benefit, however. The purpose of this review is to introduce robotic-assisted systems for use in knee arthroplasty, describe the potential advantages and limitations associated with this technology, and review several of the systems that are currently available.
A method for x-ray image-guided robotic instrument positioning is reported and evaluated in preclinical studies of spinal pedicle screw placement with the aim of improving delivery of transpedicle K-wires and screws. The known-component (KC) registration algorithm was used to register the three-dimensional patient CT and drill guide surface model to intraoperative two-dimensional radiographs. Resulting transformations, combined with offline hand–eye calibration, drive the robotically held drill guide to target trajectories defined in the preoperative CT. The method was assessed in comparison with a more conventional tracker-based approach, and robustness to clinically realistic errors was tested in phantom and cadaver. Deviations from planned trajectories were analyzed in terms of target registration error (TRE) at the tooltip (mm) and approach angle (deg). In phantom studies, the KC approach resulted in TRE = 1.51 ± 0.51 mm and 1.01 deg ± 0.92 deg, comparable with accuracy in tracker-based approach. In cadaver studies with realistic anatomical deformation, the KC approach yielded TRE = 2.31 ± 1.05 mm and 0.66 deg ± 0.62 deg, with statistically significant improvement versus tracker (TRE = 6.09 ± 1.22 mm and 1.06 deg ± 0.90 deg). Robustness to deformation is attributed to relatively local rigidity of anatomy in radiographic views. X-ray guidance offered accurate robotic positioning and could fit naturally within clinical workflow of fluoroscopically guided procedures.