 The investigators will include patients who will be schedule for total knee arthroplasty with a diagnosis of osteoarthritis. The patients will be divided in two groups. In both groups a verbal and clear detailed information will be given on the intraoperative approach. The first group will receive topical tranexamic acid and the second group topical platelet rich plasma; both in the surgical site. Both groups will be assessed before and after the intervention with clinical scales VAS and laboratory results hemoglobin, hematocrit levels and transfusion rate. 