Osteoarthritis is a common disorder in elderly patients, which seriously affects the quality of life. The disease can be treated conservatively in its early stages, but as the disease worsens, the knee joint gradually develops internal and external rotation or flexion contracture deformity, and patients often have difficulty walking and pain, which is usually worse after rainy days or exertion. Total knee replacement surgery is now an extremely mature form of treatment and may be recommended for elderly patients over 55 years of age if long-term conservative treatment is not effective. The total cost is around $45,000, and Medicare patients generally pay about $20,000 out of pocket. The requirements for joint replacement are high, and long-term results are not ideal for angular deviations of more than 3 degrees, so it is also critical to choose an experienced surgeon.