Background: The knee joint is one of the most important joints of the body that is affected by various diseases. Osteoarthritis is the most common disease involving the knee and causes symptoms including pain, swelling, limited mobility and disability. Several therapeutic approaches, including drug therapy, physiotherapy, and surgical treatments such as arthroscopic debridement and knee replacement have been used for this disease. Knee replacement is one of the most effective treatments for this disease.

Method: In a clinical trial and prospective study, 57 patients who underwent knee replacement surgery at Yazd Shahid Sadoughi Hospital in 2016, were evaluated. All patients were examined before and after the surgery, and the VAS, WOMAC, KSS, and SF-36 questionnaires were completed. Also, postoperative radiography was analyzed using KSRE form.

Results: Of the 57 patients studied, 51 were female and 6 were male. The mean age of the patients was 65.32 years. Patients have been evaluated on average 7.31 months after the operation. Based on the KSS form, the mean" Function score" of patients'  increased from 15.27 ± 24.03 before surgery to 69.96 ± 8.93 after surgery, and the mean "Knee score" of patients increased from 7.58 ± 40.43 before surgery to 82.38 ± 7.03 after surgery. The mean score of WOMAC decreased from 69.02 ± 11.02 before surgery to 25.73 ± 5.92 and the pain score in patients was decreased from 8.89±0.77 before surgery to 1.54±1.00 after surgery. The mean scores of SF-36 quality of life questionnaire increased from 45.75±18.85 before surgery to 65.26±17.86 after surgery. In the study of postoperative imaging, the mean alpha angle was 97.8 ± 0.98, the mean beta angle was 89.7 ± 1.11, the mean gamma angle was 2.57±1.62 and the mean delta angle was 86.38 ± 0.81.

Conclusion: Due to the significant improvement in pain, WOMA score, function score, knee score, range of motion and improvement in the quality of life, knee replacement surgery is an effective and curative treatment for osteoarthritis of the knee.