Robot-Assisted Total Knee Arthroplasty Accurately Restores the Joint Line and Mechanical Axis. A Prospective Randomised Study

Robot-assisted Total Knee Arthroplasty (TKA) improves the accuracy and precision of component implantation and mechanical axis (MA) alignment. Joint-line restoration in robot-assisted TKA is not widely described and joint-line deviation of > 5 mm results in mid-flexion instability and poor outcomes. We prospectively randomised 60 patients into two groups: 31 patients (robot-assisted), 29 patients (conventional). No MA outliers (> ± 3° from neutral) or notching was noted in the robot-assisted group as compared with 19.4% (P = 0.049) and 10.3% (P = 0.238) respectively in the conventional group. The robot-assisted group had 3.23% joint-line outliers (>5 mm) as compared to 20.6% in the conventional group (P = 0.049). Robot-assisted TKA produces similar short-term clinical outcomes when compared to conventional methods with reduction of MA alignment and joint-line deviation outliers.