Knee replacement surgery is a procedure where damaged sections of the knee joint are substituted with artificial components. During the operation, the muscles and ligaments around the knee are moved aside to allow access to the joint's interior. Surgeons remove the ends of the femur and tibia bones, and often the underside of the kneecap. The artificial components are then securely fixed in place. Typically, the new knee includes a metal cap on the femur, a combination of metal and plastic on the tibia, and occasionally a plastic piece in the kneecap. This surgery is generally performed on individuals, usually over 55, whose knees have been impaired by arthritis, injury, or other joint-damaging conditions, leading to severe pain, significant stiffness, instability, and deformity, such as knock-knees or bowlegs.