I often see such patients in the clinic. The pain in both knees is so severe that they can’t walk more than a hundred or eighty meters. The knee joints are deformed, either O-leg (knee inversion, rotundity), X-leg (knee valgus), or downwind leg (one side is valgus, the other side is valgus.) A is O-leg (rotundity), B is X-leg. ”Radical treatment requires joint replacement.” After hearing this, the patient often asks, “Do you want to replace the bones of the knee? How can I walk if there is no bone? Will I still have my own knee if there is no bone? (Photo from a post-operative patient) Artificial knee surface replacement is often referred to as knee replacement. The procedure originated in the 1960s and has evolved over the decades to become a very mature surgical procedure. There are now reports of follow-ups of up to twenty years or more, both domestically and internationally. In layman’s terms, surface replacement is the removal of bone spurs and hardened bone surfaces from the joint surface, which are the main cause of pain and joint deformity, while preserving as much normal bone as possible. After removal, the bone surface needs to be covered, which is done using an artificial joint, similar to the innate cartilage that wraps around the entire joint surface. This allows the joint to move in flexion and extension. However, there are also knee replacement surgeries that remove the entire bone of the knee joint, as they are called, and are often used to treat bone tumors around the knee. There is a fundamental difference between this and a normal knee surface replacement surgery. Have you ever misunderstood knee arthroplasty? We hope that reading this article will dispel your doubts and provide you with the right treatment.