Knee replacement still hurts after half a year may be due to the adaptation period, or it may be caused by wear and tear, loosening of the artificial knee joint, exertion and excessive exercise. 1. Adaptation period: Generally, there will be a 3~6 months adaptation period after knee replacement, during which pain and swelling may occur, it is recommended to minimize activities and adapt slowly. 2. Wear and loosening of the artificial knee joint: it may be that the artificial knee joint does not match the limb, resulting in excessive wear and loosening, or it may be that the surgical force line is not good, the artificial joint rubs against the surrounding tissues, and the surrounding tissues and nerves are compressed, resulting in pain, and it is recommended to go to the hospital for examination. 3. Exertion and excessive exercise: If you do more physical work or strenuous exercise after surgery, the artificial knee joint is overused, which can cause pain and swelling. After knee replacement surgery, you should avoid strenuous exercise as much as possible. If the pain is prolonged or intolerable, it is recommended to go to the hospital for examination in time.