50 patients scheduled for total knee arthroplasty were randomized to the use of either patient specific instrumentation (PSI) or conventional instrumentation (CI). Outcomes of interest included contact location on the medial and lateral condyles, the magnitude of excursion, the incidence of condylar separation and the rate of neutral alignment. Follow up was performed 2 years post-operation. Results revealed no significant differences in all outcomes between the PSI and CI groups. Furthermore, no differences in contact location or magnitude of excursion were observed between patients who had neutral alignment and those who had varus alignment.