Potential problems or complications that may arise after knee replacement surgery include: Persistent Pain: This can be an indicator of serious conditions such as infection or loosening of the prosthesis. Restricted Movement: Difficulty with knee movement or failure to achieve expected flexibility. Swelling: Abnormal or persistent swelling in the surgical area. Redness: Redness that may indicate infection or inflammation. These symptoms can be signs of potential problems and may require medical evaluation. However, the vast majority of patients do not experience such serious complications, and the surgery generally yields successful outcomes.