Osteoarthritis (OA) is one of the most frequent rheumatic diseases and the most common joint disease, primarily affecting joint cartilage and the subchondral bone of a synovial joint resulting in the y articular dysfunction. OA is recognized as a cause of disability, with significant social and financial costs due to medical, surgical interventions in addition to frequent absenteeism at work. The objective was to determine if tibiofemoral distraction, in conjunction with conventional therapy in patients with knee osteoarthritis grade 3, improved performance of the lower extremity in comparison to the conventional treatment alone, as proposed by the Ministry of Health (MINSAL). This research is a pilot, prospective randomized clinical trial (RCT), controlled, single-blind and with a balanced sample. The sample was recruited from patients of the Hospital San Borja Arriarán (Santiago, Chile) with medical diagnosis of knee OA grade 3. Two measurements were performed, one at the beginning of the 10 sessions and at the end of treatment, which was measured with the functionality questionnaire of OA of the Western Ontario and McMaster Universities (WOMAC), the pain visual analog scale (VAS), the passive joint range of motion with goniometry, and distance to the Test 6-minute walk. When comparing the two groups showed statistically significant differences in functionality, pain, distance walked and joint range, except in knee grade extension. The tibiofemoral distraction added to conventional treatment functional improvement in patients with knee OA grade 3.