80 patients undergoing minimally invasive primary total knee arthroplasty (TKA) were randomized to evaluate the efficacy of custom-fit MRI-based pin guides, compared to the standard procedure, in the reduction of blood loss, hemoglobin levels, and improving early clinical outcomes over 12 weeks. The evidence presented in this study demonstrated that drainage of blood, and surgical time were significantly reduced in minimally invasive total knee arthroplasty with custom-fit MRI-based pin guides compared to with the standard procedure. No significant differences were apparent for estimated hemoglobin loss, transfusion requirements, or the early clinical outcomes associated with each procedure.