Background: Osteoarthritis is degenerative lesions of articular cartilage, due to the biosynthesis of basic properties of cartilage cells are abnormal. Total knee arthroplasty is the surgery that replaces articular cartilage by artificial materials. This is the thorough method to treat late stage of osteoarthritis. The purpose of the present study was to evaluate the results of total knee arthroplasty in the treatment of knee osteoarthritis. Materials and method: the authors studied 50 patients (52 knees) were total knee arthroplasty in Viet Duc hospital from 11/2010 to 4/2012. The patients were evaluated with the use of Knee Score (KS) and Knee Function Score (KFS) scale. Retrospective cohort study and descriptive statistics ( SPSS 16.0 soft-ware). Results: With the mean duration of follow-up was 13 months. The mean preoperative KS was 48.14 + or - 8.12, postoperative KS was 86 + or - 7.61. The mean preoperative KFS was 40.1 + or - 9.61, postoperative KFS was 82 + or - 7.76 (p0.05). The mean range of motion 113.2 + or - 5.2. The proportion of postoperative Knee Society Score was 80.77 percent of excellent, 13.46 percent of good, 5.77 percent of fair. There was one patient with pain of patellofemoral articular. Conclusions: Total knee arthroplasty yielded good pain relief for patients with later stage of osteoarthritis.