Surgical accuracy of image-free versus image-based robotic-assisted total knee arthroplasty

Background: This study investigated the accuracy in achieving proper lower limb alignment and component positions after total knee replacement (TKR) with image-free and image-based robotic-assisted TKR.Methods: A total of 129 patients (166 knees) suffering from end-stage knee arthritis who underwent TKA operated by robotic-assisted surgery between the years 2018 and mid-2021 were recruited. Radiological outcomes were compared between image-free and image-based robotic-assisted surgical systems.Results: There were significant differences between the two robotic systems when comparing the mean planned component alignment and the mean measured alignment on radiographs, in which the image-free robotic-assisted system was more varus, whereas the image-based robotic-assisted system was more valgus for both the mean femoral and tibial component coronal alignment (p < 0.001). For tibial component sagittal alignment, the image-based group had a larger deviation from the planned posterior slope (p < 0.001).Conclusion: Image-free and image-based robotic assisted TKR had differing accuracy in femoral and tibial alignment.

Automated summary

This study compared the accuracy of achieving proper lower limb alignment and component positions after total knee replacement (TKR) with image-free and image-based robotic-assisted TKR. The results showed that there were significant differences between the two robotic systems in the alignment of the femoral and tibial components. The image-free system was more varus, while the image-based system was more valgus in the coronal alignment. The image-based system also had a larger deviation from the planned posterior slope in the sagittal alignment of the tibial component.