133 patients scheduled for total knee arthroplasty were randomized to the procedure with the use of either patient-specific instrumentation or conventional intramedullary instrumentation. Patients were assessed postoperatively using CT to determine the deviation of component positioning and lower limb alignment from targeted values. The results demonstrated no significant differences between groups in mean deviation from targeted alignment, and a significantly higher incidence in tibial slope outliers (>3-degree deviation) in the PSI group compared to the conventional group.