When the big day arrives, the patient will be connected to heart leads and monitors that register heart rate and the body's level of oxygen.
The knee will remain bent during the surgery so that the surgeon can see as much of the joint as possible. The area around the knee will be cleaned with antiseptic liquid, a tourniquet may be applied above the knee to limit bleeding and then an incision will be made. The incision is usually 6 to 12 inches (15 to 30 centimeters) long.
Once the kneecap has been carefully moved aside, the surgeon concentrates on removing damaged bone tissue, being careful to leave not only enough bone to attach the implant, but enough bone to attach a second replacement later if the first one wears out over time.
Generally, bone is removed from the end of the femur, as well as from the front and back sides of the bone end. This allows the prosthesis to fit correctly. Bone is also removed from the top of the tibia, so that the end of the tibia is flattened. Any damaged tissue on the back of the kneecap will also be removed. The bones will be measured and the surgeon will insert the prosthesis once he or she is sure it will fit correctly.
Once the implant is secured, the surgeon may realign the ligaments to guarantee optimal function. Any tissue that has been cut in the operation to provide access to the joint will be sewed back in place. A drainage tube may be inserted to allow fluid to exit the wound. Then the incision is closed, the knee is bandaged and the procedure is over. The entire thing lasts about two hours.
All done. Now what happens? And what can go wrong?