I. What is the need for an artificial knee joint Before answering this question, I would like to briefly introduce the basic knowledge about the knee joint, and I will try to avoid using too specialized words when introducing it in order to be understood by the majority of patients. The knee joint is composed of the lower femur (thigh bone), the upper tibia (calf bone) and the patella, which are in contact with each other. The knee joint is an important joint in the human body and is used every day from birth until a person starts walking. Under normal circumstances, the knee joint moves against each other when the human body is engaged in activity because the cartilage on the surface of the bone moves against the cartilage, which is flexible and wear-resistant. Why the knee joint is prone to problems: To answer this question is more complex and involves more things, so I can only briefly introduce it. I will not go into the joint pathology caused by bone and intra-articular damage due to sports trauma in young people, but I will focus on the problems that commonly occur in middle-aged and older people. There are reports in the literature that the incidence of osteoarthrosis of the knee is upwards of 50% in people over 60 years of age, and I feel the same way when I see patients in outpatient clinics. Many middle-aged and elderly patients often tell me that they have joint pain when walking up and down stairs, squatting, or even walking on level ground, and that some patients need to walk with crutches. When it comes to wear and tear, it’s easy to understand. Everything wears out over time, and human joints are no exception, and the knee joint is special. The degree of wear and tear is generally related to two conditions, that is, two “quantities”, one is the number and the other is the weight. The more you use it, the heavier the wear will be. The weight is not well understood by the general public, the weight I am talking about here is the weight of the human body weight, the human knee joint development maturity, the female in about 18 years old, the male in about 20 years old. At this age, weight is often relatively light, especially in this period of girls some weight about 90-100 pounds, but after the age of 40-50 years, some in the marriage after the birth of a child weight increased a lot, reaching 140-150 pounds, or even more. The increased weight puts a lot of pressure on the knee joint, and the wear and tear on the knee joint during daily activities or general exercise can be several times the normal weight, so imagine what it would be like to walk around with 50 pounds of weight on your shoulders every day if you weighed 100 pounds when you were young and 150 pounds when you were middle-aged. I see this a lot in my outpatient practice, where the wear and tear on the knee joint varies greatly depending on the age and weight. The vast majority of the patients I have performed artificial knee replacements on the ward are overweight patients. Of course, in addition to the two amounts I mentioned above, there are other concomitant factors such as uneven forces on the joint surface due to O-leg and X-leg, joint instability due to ligament damage within the joint, and unevenness of the joint surface after a fracture within the joint that can also cause excessive joint wear. First, the cartilage in the joint is damaged. Cartilage is a very special tissue that does not have blood circulation, which means that it does not rely on blood for nutrition, but on joint fluid to provide nutrition. Long-term repeated friction on the joint, as well as trauma and excessive weight bearing will lead to cartilage tissue from surface damage → deep damage → loss of cartilage → narrowing of the joint space → “bone-to-bone” friction in the joint → hardening of the bone surfaces in contact with each other → bone growth around the bone surfaces of the joint, due to “bone-to-bone Due to the “bone-to-bone” friction, many bone particles are generated, forming intra-articular free bodies, and these small free bodies will invade into the joint space to form similar to the sand in the eyes to aggravate the wear and tear of the joint, due to the increasing number of bone wear particles gathered together to form a larger free body. Many patients often have the misconception that it is the “bone spurs” in the joints that cause joint problems, but in fact it is the “bone spurs” that cause problems in the joints, which means that the cartilage in the joints must have a considerable degree of wear and tear when you find bone growth in the joints. This means that the cartilage in the joint must have worn down considerably by the time you get the osteophytes. We call this disease osteoarthrosis of the knee or osteoarthritis, but the meaning is the same. In the early stages of the disease, joint pain occurs only when walking up or down stairs or when squatting, but this gradually worsens as time goes on, and pain occurs when walking on level ground, and the range of motion of the joint gradually decreases, even affecting squatting. My patients often tell me that they can walk on level ground, but it is very difficult to go up and down stairs or squat, especially on higher steps, which is almost impossible to go up without the help of other things. This is a typical symptom of patients in the middle and late stages of the disease, and further development of the disease requires the help of a cane to walk on level ground. This disease has a great impact on daily life and seriously affects the quality of life of middle-aged and elderly patients, and the number of outpatient visits has increased year by year in recent years. When osteoarthritis of the knee develops to an advanced stage, patients often experience pain going up and down stairs, even walking on flat ground, recurrent swelling of the joint, “fluid accumulation” in the joint, and a significant reduction in the distance and time they can walk freely. In this period, I had many such patients who pleaded with me to prescribe medication or injections to cure their “leg problems”, but after examination and radiographs, it was found that the knee joint had worn out more seriously, and some patients had great difficulty walking, even “bending” the joint. Some patients have serious difficulties walking, even “bending” the joint, and also have joint deformities. In this case, the problem cannot be solved with medication or intra-articular injections, but I would like to say a few more words. For patients in the early and middle stages, when the joint pain is not very severe and the joint lesions are relatively mild, conservative treatment is possible. However, when it comes to conservative treatment, try to go to a large hospital that specializes in joint surgery, especially when it comes to intra-articular injections, the dosage and time should be strictly controlled, especially when it comes to joint closure treatment. I have encountered more than one patient, in a short period of time outside the hospital for multiple joint closure treatment, this is not appropriate, in general, only once a month injection, repeated injections will have adverse consequences. I am talking about joint closure therapy here, not intra-articular “lubricant” injections, so I won’t go into too many conservative treatment methods here, otherwise the text would be irrelevant. In short, when osteoarthritis of the knee is advanced and affects joint movement with severe pain, affecting daily life, and when conservative treatment has no significant effect, surgery is indicated. Second, how to perform artificial knee joint replacement? How do I have knee replacement surgery and can I still walk after surgery? This is a question that is often asked by patients and is also the most important concern for them. In order for patients to have a basic understanding of the surgery, I would like to give a brief introduction to artificial knee replacement surgery. The procedure is generally called an artificial knee replacement, but we also call it a surface knee replacement, which is a more accurate name. We simply remove 8-10 millimeters from the broken joint surface during surgery, measure the size of the bone on site during surgery, and install the appropriate artificial joint. This type of surgery causes very little damage to the bone and not much damage to the stable structures within the joint, and the joint is relatively stable after the surgery. For an experienced surgeon this surgery can be done in about an hour. In general, you can walk on the ground within three days after surgery. Of course, artificial knee replacement surgery is more technical and not as simple as it is said to be. The surgeon must accurately grasp the angle of rotation and valgus of the artificial joint during surgery, and only if the artificial joint is installed properly can we receive good results. Third, how long after surgery can be recovered in general three months after surgery can be completely restored to walk freely, everyone’s situation is different, I also have many patients after surgery one and a half to two months has been walking very well. Of course the recovery after surgery is closely related to the situation before surgery. If the patient has had the disease for a long time and has poor knee movement, the recovery time after surgery will be extended because she has to strengthen the joint function exercises, so the artificial knee replacement surgery cannot be performed too late. In addition, heavier patients will have a slower recovery time than lighter ones, and older patients will have a slower recovery time than younger ones. In addition, hospitals that have specialized joint units usually have post-operative rehabilitators to help patients recover after surgery, so patients generally recover satisfactorily after surgery. Recently, my patients have been asking me a variety of questions about the knee, some about the treatment of osteoarthrosis of the knee and some about knee arthroplasty. The questions cover a wide range of topics. I often answer individual questions, but as patients’ medical knowledge continues to improve, so does the depth and expertise of the questions asked, so I think it is necessary to provide a comprehensive answer based on the content of previous questions asked by patients so that the majority of joint surgery patients can be more fully informed.