Many patients who are introduced to knee replacement surgery treatment feel “abnormal, abnormal sensation, numbness, pain, abnormal walking for some time after surgery …… What is this all about? What should I do? Why is there a “numbness” or “electrical” pain around the wound? After surgery, many patients feel numbness around the wound, especially in the lower part of the lateral knee joint. In fact, this phenomenon is very common and patients should not be nervous. The reason for this phenomenon is the surgical incision. The incision is usually longitudinal, and the nerves at the knee joint run from inside to outside, sloping downward. Therefore, it is inevitable that the lateral cutaneous nerve will be cut during the artificial knee replacement and the patient will feel numb after the surgery. Over time, the numbness will become less and less extensive, and will largely disappear after about two years. Why do the joints feel swollen and warm, and how long does it take to recover? During the normal post-operative recovery process, patients often feel warmth in the joints. If you feel it with your hand, you will find that the skin temperature on one side of the replaced joint is 0.5 to 1 degree higher than the other side, and the difference is even greater especially after doing rehabilitation training. We have used a thermometer to check the patient’s condition after exercise, and in some cases, the skin temperature at the joint was even as high as 38 degrees. Therefore, if the joint becomes swollen and hot within six months after surgery, patients are advised to use ice to deal with it. This is because such fever may be caused by a reaction of the metal in the artificial joint in the body. However, if after six months, there is still significant swelling and fever, patients are advised to contact their primary surgeon to check for infection. Why do I have pain or soreness in the affected limb at night and stiffness in the morning before I get up? During post-operative rehabilitation, as the intensity and frequency of training increases, some patients can experience soreness in the joint at night and stiffness in the morning when they wake up, especially with greater activity during the day. The intensity of the pain is related to the patient’s preoperative knee function status. The lower the knee function score, the more pronounced the training-induced pain may be. Why do I always feel tightness around the knee joint? This is mainly due to post-operative scar formation, which can be gradually pulled away with exercise and the sensation will disappear. Why do I feel stiff or unnatural when walking? After an artificial knee replacement, the patient is considered to have achieved the desired result as long as he or she can take care of daily activities without joint pain and the joint flexes and extends to the desired degree. Early post-operative stiffness is normal and is usually relieved to varying degrees within 6-8 weeks, and knee mobility is basically restored within 3 months after surgery. Why do some patients have a “clicking sound” in the knee joint during activity? This sound is usually due to the soft tissues around the prosthesis still being loose at the time of installation, muscle weakness and lack of sufficient strength to maintain balance. It is caused by the collision between the prosthesis and the femoral condyles when the prosthesis is moved, especially the hip bone. This sound rarely has clinical symptoms, but can cause psychological tension in the patient. Over time, this sound will disappear as the soft tissues repair their own balance. However, when the symptoms are obvious, a medical professional should be consulted to rule out the possibility of hip slippage. In conclusion, the above phenomenon is a normal reaction in the rehabilitation and functional training after artificial total knee arthroplasty, and patients do not need to worry about it so much that they lose their courage and confidence in further rehabilitation treatment, which will affect the recovery of postoperative joint function. In addition to taking advantage of the outpatient review opportunity to receive professional advice on the recovery of the prosthesis and the function of the affected knee, patients should consult with a physician to identify any other problems that arise during the late rehabilitation process.