42 patients scheduled for total knee arthroplasty were randomized to surgery completed with either patient-specific instrumentation or conventional instrumentation. Patients were assessed after 1 year for varus-valgus stability, lower limb and individual component alignment, and clinical scores. Results demonstrated no significant differences in knee stability and clinical scores. Additionally, lower limb and individual component alignment did not significantly differ between groups, with the exception of a significantly smaller tibial slope among the PSI group compared to the CONV group.