140 patients scheduled for total knee arthroplasty were randomized to have the procedure completed using either patient specific instrumentation or conventional intramedullary instrumentation. The purpose of this study was to compare radiological, clinical, and perioperative data between groups. The primary outcome was the incidence of outliers in mechanical axis alignment, with >3degrees deviation from neutral alignment considered an outlier. In addition, coronal and sagittal component alignment (with >3deg deviation from preoperative planned alignment considered an outlier), operative data (blood loss, operative time, length of stay), and clinical outcome were assessed. Results demonstrated no significant differences between groups for any of the assessed outcomes.