51 patients with osteoarthritis of the knee were randomized to receive either intramedullary or extramedullary tibial instrumentation, during minimal invasive surgery in total knee arthroplasty (MIS-TKA). Leg alignment and tibial slope were measured throughout the course of the study in order to determine which instrumentation resulted in better alignment, and as a result, increased TKA survival rate. By the end of the 12 month study, the study determined that there was no significant difference in leg alignment between MIS-TKA with intramedullary or extramedullary tibial instrumentation, but MIS-TKA with extramedullary instrumentation was significantly better at restoring the tibial slope.