45 patients scheduled to undergo total knee arthroplasty (TKA) were randomized to receive either patient-specific or conventional instrumentation. The purpose of this study was to compare these two techniques with respect to the rotational alignment of both the femoral and tibial components, as assessed by computed tomography (CT). Results at 1 week post-operation indicated that, although there was no significant difference between groups with respect to both femoral and tibial component rotation, the dispersion of tibial rotation from a neutral position, both internally and externally, was greater in the conventional instrumentation group.