Osteoarthritis of the knee, also known as degenerative arthritis of the knee, senile arthritis, hypertrophic arthritis or osteophytes (bone spurs), is a frequent and common condition in the elderly female population. The etiology of osteoarthritis of the knee can be attributed to age-related degenerative changes in the knee cartilage, and from this point on the course of the disease is irreversible. Patients with early onset of the disease may have knee discomfort from their forties onwards, typically in the form of pain, especially when walking up and down stairs. At this time, there are no abnormalities on x-rays and no obvious positive signs on physical examination, which is considered early mild osteoarthritis. In moderate osteoarthritis, the pain and other discomfort symptoms are aggravated, and there may be mild bone redundancy on X-rays and narrowing of the joint space (especially in the patellofemoral joint), and on physical examination there is mainly a subtle rubbing sensation on the patellofemoral joint surface, and sometimes a mass (N-fossa cyst) can be felt from the back of the knee. In severe cases, the pain is obvious and walking is limited, even if not relieved by painkillers. In acute attacks, there may be swelling and fluid accumulation in the knee joint, and more joint fluid may be extracted from the joint cavity. Treatment of osteoarthritis of the knee varies according to its severity. Generally speaking, mild cases are treated mainly with maintenance, supplemented by appropriate medication. For moderate patients, in addition to the above measures, sodium hyaluronate can be injected into the knee joint, usually once a week for five weeks, with satisfactory results in most patients; for severe patients, if there is fluid in the joint, hormonal drugs can be injected into the joint after puncture and fluid extraction to inhibit inflammatory response. However, in general, conservative treatment is often ineffective and the patient has difficulty in obtaining sustained pain relief, which in turn affects the function of the knee and daily life, and it is time to solve the problem surgically. There are a variety of surgical options, but if the degeneration of the knee joint is really severe, the only option is to have a knee arthroplasty. Total knee arthroplasty is an effective treatment for severe knee osteoarthritis, which is performed by reconstructing the knee joint to relieve pain and improve function. During the surgery, the surgeon removes all the worn cartilage surfaces of the upper and lower knee joints, i.e., the femur and tibia, and then installs metal femoral and tibial prostheses to restore normal physiological function of the knee joint by reconstructing the alignment of the knee joint, correcting the line of force of internal and external rotation, and re-establishing soft tissue balance. At present, total knee replacement surgery is widely performed in large hospitals in China and is technically very mature, with satisfactory postoperative follow-up results. In some special cases, if only one side of the articular surface is particularly damaged while the other side is basically intact, then unicondylar knee replacement is a good option, with the advantages of less trauma, faster recovery, and easier secondary revision surgery in the future, and is now also being performed clinically. In total knee replacement surgery, there are two types of surgery, patellar replacement and non-patellar replacement, which need to be decided on a case-by-case basis. In conclusion, knee replacement surgery has been shown to be a safe and effective treatment for patients with osteoarthritis whose knee joints have been severely damaged.