Osteoarthritis of the knee joint (commonly known as osteophytes, bone spurs, etc.) is a common disease in middle-aged and elderly people, especially in women. According to statistics, about 80% of people over 60 years of age visit the hospital for knee osteoarthritis. In order for middle-aged and elderly people to understand osteoarthritis-related knowledge so as to obtain the best treatment, this article introduces this knowledge. If there is no deformity of the knee joint, the symptoms will not be very heavy and will be light and heavy at times. These patients should exercise their muscles (mainly the quadriceps, i.e., straighten the knee joint, tense it, lift the lower limb with a straight knee), reduce their body weight, and take anti-inflammatory and pain-relieving drugs (such as Fotarine, Fenbid, etc.) and cartilage-protecting drugs (chondroitin sulfate or hydrochloride, etc.) when the symptoms are heavy. Most of the patients will not progress to the extent that surgery is required. If the joint has mechanical symptoms, such as occasional joint jamming when walking, accompanied by severe pain, which is relieved after a short rest and change of position, it indicates that the meniscus in the joint is ruptured or there is a free body in the joint. These patients should undergo minimally invasive surgery (arthroscopic surgery) as soon as possible after diagnosis to remove the ruptured meniscus or remove the free body to avoid further damage to the cartilage in the joint. In these patients, medication or muscle exercise alone will not solve the problem. Arthroscopic surgery is less invasive (1 cm incision) and recovery is faster (3-4 days hospital discharge). For osteoarthritis with combined knee deformity (mostly internal knee, commonly known as rotundity and O-leg), the deformity should be corrected in time. If the patient is younger (less than 60 years old), the deformity is not heavy, and the articular cartilage is still preserved (confirmed by taking weight-bearing X-rays), then a high tibial osteotomy should be performed to correct the deformity, which will relieve the symptoms and allow the damaged cartilage to be repaired, avoiding (in some patients) or delaying (in some patients) the arthroplasty. Patients over 60 years of age who have a combined inversion (or valgus) deformity of the knee, moderately advanced osteoarthritis with severe symptoms and extensive wear of the medial articular cartilage should receive an arthroplasty. There are three types of artificial knee joints to choose from: unicondylar replacement if one gap (internal or external) is diseased and the other gaps are basically normal; patellofemoral replacement if the patellofemoral joint is broken; or total knee replacement if the whole joint is defective. Compared with total knee replacement, the first two types of joint replacement (unicondylar and patellofemoral) are less traumatic and have faster recovery. However, most patients in China are delayed, so most patients have to undergo total knee replacement. Many people have fears and concerns when it comes to knee replacement surgery, but they are unnecessary. Modern knee replacement surgery has been performed for more than 40 years, and the number of surgeries performed in the United States is over 400,000 per year (expected to reach 1.5 million by 2030), while the population of China is four times that of the United States, but the number of surgeries is only 30,000 to 40,000, which is clearly disproportionate. This type of surgery is safe and effective, with a surgical mortality rate of 2 to 3 per 10,000. If diabetes is controlled, perioperative antibacterial, and strict aseptic operation, the infection rate can be below one percent. It is inevitable that patients are concerned about pain during surgery. In the last five years, both domestic and foreign countries have attached great importance to the research of perioperative pain relief methods and proposed to make hip and knee joint replacement painless surgery. The orthopedic department of China-Japan Friendship Hospital has established the procedures of painless surgery, i.e. preoperative medication, intraoperative long-acting anesthetic closure, postoperative pain pump, etc., to ensure painless recovery of patients’ postoperative rehabilitation. After knee replacement, patients can walk painlessly, joint movement reaches near normal joint level (flexion greater than 110°), can sit in a low chair, can squat to the toilet, and most importantly, can stop using pain medication. This is because few people escape the disaster of gastric and duodenal ulcers with the long-term (greater than 3 months) application of such drugs, whether Chinese or Western. A successful artificial knee replacement can be used for more than 20 years without loosening or wearing out. Of course, this requires the experience of the surgeon. The minimum requirement for an experienced surgeon is to perform at least 60 knee replacements per year, with a total of at least 200. Therefore, it is essential that you seek out these surgeons to perform your surgery.