Background and Objectives: Total knee arthroplasties (TKAs) are the most effective surgical treatment for end-stage knee osteoarthritis. The tourniquet is used to reduce intraoperative blood loss, improving surgical field visualization. There is much controversy regarding the effectiveness and safety of using a tourniquet during total knee arthroplasties. The purpose of this prospective study is to determine the effect of tourniquet usage during TKAs on early functional outcomes and pain in our center.Materials and Methods: We conducted a randomized controlled trial of patients following a primary total knee replacement between October 2020 and August 2021. We recorded presurgical data, which included age, sex and knee range of motion. Intraoperatively, we measured the amount of blood aspiration and the surgical room time. After the surgery, we measured the amount of blood aspirated through the drains and the hemoglobin. We measured flexion, extension, Visual Analogue Scale (VAS) scores, and Western Ontario and McMaster Universities Arthritis Index (WOMAC score) scores for the functional evaluation.Results: We included 96 patients in the T group and 94 in the NT group, respectively, who remained until the last follow-up. Regarding blood loss, the NT group demonstrated significantly lower levels: 245 ± 97.8 mL intraoperative and 324.8 ± 151.65 mL postoperative, compared to the T group, where we recorded 276 ± 109.2 mL during the surgical procedures and 353.44 ± 101.55 mL after the surgery, (p< 0.05). We also recorded significantly shorter operative room time for the NT group, (p< 0.05). During the follow-up, we noticed postoperative improvements but without significant differences between the groups.Conclusions: We found a significant decrease in bleeding after no tourniquet usage during total knee replacements and shorter operative times. On the other hand, the knee function demonstrated no significant differences between the groups. Further studies may be required in order to assess complications.