Accuracy Of Bone Cuts,Lower Limb Alignment And Component Size Prediction In Robotic-assisted Total Knee Arthroplasty

Purpose: Robotic-assisted total knee arthroplasty theoretically allows for accurate bone cuts,good lower limb alignment,and accurate component size prediction,and is less influenced by the surgeon’s experience level.The main objective of this study was to compare the accuracy of bone cuts,lower limb alignment,and component size prediction in robot-assisted total knee arthroplasty,and to preliminarily investigate whether the use of robot-assisted total knee arthroplasty by surgeons with different levels of experience would have different effects in terms of bone cuts accuracy,and lower limb alignment.Methods: This study is divided into two parts,the first of which compares the accuracy of bone cuts accuracy,lower limb alignment,and component size prediction in roboticassisted total knee arthroplasty.Clinical data were retrospectively collected from 45 patients with end-stage osteoarthritis who underwent robotic-assisted total knee arthroplasty at The People’s Hospital of Liaoning Province between December 2021 and June 2022,including 36 females and 25 left knees,with an age range of 44-88 years and a mean age of 66.6 ± 8.1 years.The preoperative planned bone cuts thickness,lower limb alignment,and component size for all patients were used as the control group,and the actual postoperative recorded bone cuts thickness,component size,and actual measured lower limb alignment were used as the experimental group,and the differences in preoperative planning and actual postoperative bone cuts accuracy,lower limb alignment,and component size were compared using paired t-tests or Wilcoxon rank sum tests.The second part compares the differences in bone cuts accuracy and lower limb alignment between surgeons with different levels of experience using the robotic system,with a oneway ANOVA or Kruskal-Wallis test used for comparison between multiple groups.Results: In terms of bone cuts actual error,no significant differences were observed in the remaining five bone cuts positions(P > 0.05),except for a significant difference observed in the distal lateral femoral bone cuts(P < 0.05).With regard to the absolute bone cuts error,the mean absolute bone cuts error in both medial and lateral tibia did not exceed 1.40± 0.96 mm,and the mean absolute bone cuts error in both medial and lateral tibial positions did not exceed 0.96 ± 0.66 mm,and all errors were less than 3 mm(100.00%)except for the bone cuts error in the medial tibial plateau(91.67%)and the bone cuts error in the lateral tibial plateau(95.83%).In terms of actual limb alignment error,a significant difference was observed for LDFA(P<0.05),while no significant difference was observed for both HKA and MPTA(P>0.05).In terms of absolute limb alignment error,the mean value of absolute limb alignment error did not exceed 1.30±1.12° for HKA and 0.89±0.08°for LDFA and MPTA,and 85.41% for HKA within 3° and 85.74% and 83.12% for LDFA and MPTA within 2°.There was a statistically significant difference in polyethylene size error compared to the preoperative plan(P<0.05),and no significant difference was observed for femoral component size and tibial component size error(P>0.05).Of all the component size prediction accuracies,100%,89.58%,and 87.50% were predicted for femoral component,tibial component,and polyethylene sizes,respectively.No significant differences were observed between surgeons both in terms of actual and absolute error in bone cuts and in terms of actual and absolute error in limb alignment(P > 0.05).Conclusions: 1.Robotic-assisted total knee arthroplasty demonstrated highly accurate bone cuts accuracy,good lower limb alignments and accuracy of component size prediction compared with preoperative planning.2.The bone cuts accuracy,lower limb alignments,and accuracy of component size prediction of robotic-assisted total knee replacement were less affected by surgeons’ experience,although no significant differences in bone cuts were shown,with experienced surgeons having an HKA closer to0°.3.The robotic system may be suitable for younger surgeons to help them achieve optimal bone cuts and limb alignment in the face of a shortened learning curve while the demand for TKA is rapidly increasing.