Background Our objective was to compare the coronal mechanical axis after total knee replacement (TKR) obtained in three groups of patients subjected to conventional, navigated, and robotic surgery. Methods Retrospective analysis. Results 124 knees were included (36 conventional, 41 navigated, 47 robotic). No statistically significant differences were found between the postOp tibiofemoral angle of the conventional, navigated and robotic groups (p = 0.396). A repeated‐measure analysis of preOp‐to‐postOp also found no significant differences (p = 0.387). There were no differences in the proportion of outliers (3‐degree) found (p = 0.211). Nevertheless, a higher proportion of patients in the robotic group improved their mechanical alignment, as compared with conventional surgery (p = 0.023), although no differences were found when comparing with navigation (p = 0.121). Conclusions No statistically significant differences were found with respect to the postOp alignment achieved. However, statistically significant differences were detected between robotic and conventional surgery when considering the percentage of patients with improved limb alignment.