Assessment of Bone Resection Accuracy in Robotic-Arm-Assisted Total Knee Arthroplasty: A Prospective Observational Study

Introduction: Robotic-arm-assisted total knee arthroplasty (RA-TKA) has emerged as a promising intervention for degenerative osteoarthritis of the knees. Nevertheless, the accuracy of this intervention is inadequately studied. This study aimed to evaluate the accuracy of bone resections in the distal femur and proximal tibia during total knee arthroplasty (TKA) performed with Stryker’s MAKO® robotic arm interactive orthopedic system. Materials and Methods: This single-center, prospective observational cohort study focused on patients with end-stage degenerative knee osteoarthritis who underwent RA-TKA performed by a single surgeon from September 2023 to March 2024. The bone resection accuracy was verified in two steps: In vivo verification using Stryker’s planar probe and in vitro manual verification using digital vernier calipers. Results: Among 55 patients included in the study, 63.6% were males. The mean age of the patients was 59.15 ± 8.31 years (Range: 42–78). Primary osteoarthritis accounted for 92.7% of cases, while secondary osteoarthritis constituted 7.3%. The mean absolute difference for medial and lateral tibial cuts was 0.29 (0.45) mm and 0.38 (0.53) mm, respectively, and medial and lateral distal femoral cuts was 0.16 (0.19) mm and 0.41 (0.51) mm, respectively. Of the total 55 bone resections, 52 (95%) had an accuracy of <1 mm. Conclusion: The Stryker MAKO® robotic system demonstrated high-level precision in bone resections, with accuracy levels exceeding those reported in the literature for conventional jig-based TKA. Preserving bone stock is crucial for revision surgeries and long-term joint health. These findings validate the system's technical reliability and support the continued integration of robotic technology in knee arthroplasty. Keywords: Bone resection, implantation, mechanical alignment, robotic-arm-assisted total knee arthroplasty, total knee arthroplasty.