(i) Severity and duration of pain Artificial total knee arthroplasty is indicated only for advanced knee lesions other than infection and severe neuroarthritis. The duration of pain and dysfunction in the affected knee should be longer than one year before knee replacement is recommended to the patient. The option of total knee replacement should be considered only when all conservative treatments have failed for at least six months and the radiographs show advanced disease. (If the patient does not request surgery from the heart, but reluctantly accepts it, the patient will be strongly dissatisfied with the outcome of the surgery, which may lead to a medical lawsuit in case of deviation. (c) Previous treatment methods are ineffective Previous treatment methods include regular use of non-steroidal anti-inflammatory drugs for more than 3 months, and local rest and physical therapy measures are not effective. Some patients have undergone arthroscopic clearing or high tibial osteotomy but the pain persists or recurs. (iv) Ability to understand and cooperate with post-operative rehabilitation If the patient is poorly compliant and unable to cooperate with post-operative rehabilitation; or if the patient is unable to walk after surgery despite a severe lesion, the patient is not suitable to receive an arthroplasty.