Accuracy of a New Robotically Assisted Technique for Total Knee Arthroplasty: A Cadaveric Study

Abstract

Background: Although the utility of robotic surgery has already been proven in cadaveric studies, it is our hypothesis that this newly designed robotically assisted system will achieve a high level of accuracy for bone resection. Therefore, we aimed to analyze in a cadaveric study the accuracy to achieve targeted angles and resection thickness. Methods: For this study, 15 frozen cadaveric specimens (30 knees) were used. In this study, Zimmer Biomet (Warsaw, IN) knees, navigation system, and robot (ROSA Knee System; Zimmer Biomet) were used. Eight trained, board-certified orthopedic surgeons performed robotically assisted total knee arthroplasty implantation using the same robotic protocol with 3 different implant designs. The target angles obtained from the intraoperative planning were then compared to the angles of the bone cuts performed using the robotic system and measured with the computer-assisted system considered to be the gold standard. For each bone cut the resection thickness was measured 3 times by 2 different observers and compared to the values for the planned resections. Results: All angle mean differences were below 1 and standard deviations below 1. For all 6 angles, the mean differences between the target angle and the measured values were not significantly different from 0 except for the femoral flexion angle which had a mean difference of 0.95. The mean hip-knee-ankle axis difference was À0.03 ± 0.87. All resection mean differences were below 0.7 mm and standard deviations below 1.1mm. Conclusion: Despite the fact that this study was funded by Zimmer Biomet and only used Zimmer Biomet implants, robot, and navigation tools, the results of our in vitro study demonstrated that surgeons using this new surgical robot in total knee arthroplasty can perform highly accurate bone cuts to achieve the planned angles and resection thickness as measured using conventional navigation. Funding: This study is funded Zimmer Biomet.

The Functionality of a Novel Robotic Surgical Assistant for Total Knee Arthroplasty: A Case Series

“…In order to achieve these goals, the robotic arm assists in positioning the cutting jigs in the appropriate planned cutting plane. In cadaveric studies, this robotic system has demonstrated 100% accuracy to within 3 degrees of goal for tibial and femoral coronal angles, tibial slope, and the hip-knee-ankle angle [18]. Additionally, that study demonstrated planned resections to be within 2 mm of goal in >90% of the specimens reviewed.…”

“…This enables the robot to identify the knee in space and allows the surgeon to make real-time intraoperative, patient-specific adjustments according to the patient's unique anatomy. The robotic arm assists in positioning the cutting jigs in the planned cutting plane and allows for accuracy down to 0.5 mm [7,18].…”

“…With this novel robotic system, the ability to perform submillimeter bone resections allows the surgeon to balance the knee through boney resections versus soft tissue releases [7,18]. This also allows the surgeon to adjust both distal femoral and proximal tibial cuts appropriately, to help minimize the risk of patella baja, thus keeping the joint height appropriate.…”

What are the benefits of robotic-assisted total knee arthroplasty over conventional manual total knee arthroplasty? A systematic review of comparative studies

“…Regarding the radiological findings, lower incidence of outliers was assessed for mechanical axis (θ), coronal (a) and sagittal (g) femoral inclinations and coronal (b) and sagittal (d) tibial inclinations confirming the higher accuracy and precision of the technique. The high degree of accuracy was demonstrated in the cadaveric study by Parratte et al , 19 using the Rosa Knee System (Zimmer-Biomet, Warsaw, Indiana, USA). The author reported no significant difference compared to the preoperative plan in resection angles (except for the femoral flexion angle, mean difference of -0.95°); no differences regarding the thickness of the resection (except for the distal medial femoral and medial proximal tibial cuts) and the hip-knee-ankle angle mean difference was -0.03°±0.87°.…”

“…cobot), while the surgeon performs the bone cuts. 19 Conversely, the Navio Surgical System and the Mako Robotic Arm Interactive Orthopaedic system do not require cutting blocks but creates stereotactic boundaries that assist the surgeon in the tibial and femoral resections.…”