Total knee arthroplasty is a treatment that removes the joint surface that cannot be repaired by the body itself and replaces the damaged joint with an artificial joint component to restore the function of the knee joint. The purpose is to relieve pain, stabilize the joint, correct the deformity, and enable the joint to move and greatly improve the function of the previously stiff and restricted joint. It is similar to fitting a broken tooth with a set of “braces” and is currently an effective treatment for serious joint disorders. Total knee replacement surgery can give patients a pain-free, mobile joint and greatly improve their quality of life. In principle, elderly people around 60 years of age with severe bone destruction on knee x-ray, significant pain, standing or walking dysfunction due to deformity and/or twinning and instability of the joint are surgical indications for total knee replacement. According to the consensus of the orthopaedic community, the best time to undergo knee replacement is between the ages of 60 and 75. Because people 60 years and older have a high incidence of osteoarthritis, the prevalence can be more than 20%. In addition to the higher incidence, patients in this age group are also in better physical condition, which allows them to tolerate the procedure and to perform post-operative functional exercises better, thus allowing them to enjoy the improved daily life after surgery. According to studies, more than 90% of knee prostheses last 20 years, 80% last 30 years, and 70% are still in good condition after 40 years of use. Therefore, younger patients can still safely undergo total knee replacement surgery. Furthermore, as senior patients over 75 years of age age grow older, their underlying diseases such as hypertension, diabetes, cardiovascular disease and other coexisting diseases increase and their health deteriorates, and knee diseases such as osteoarthritis gradually worsen. If the patient’s condition progresses to the point where he or she loses the ability to walk and has to be bedridden and also has a large number of coexisting underlying diseases, the risk of further surgery is high. Therefore, patients over the age of 75 should take advantage of the timing of surgery and undergo surgery as soon as possible. In conclusion, the majority of patients who undergo total knee arthroplasty will experience many benefits such as elimination of joint pain, greatly improved joint function, and improved quality of life.