Last updated: 11/24/2009

Most knee revision operations take about three hours to perform and are similar to knee replacement procedures. After the patient has been anesthetized, the surgeon opens the knee joint by cutting through the joint capsule. The first step in revision...

surgery is the removal of the old femoral component of the knee prosthesis. After the metal shell has been removed, the damaged bone at the end of the femur is scraped off and the femur is reshaped. If the bone is weak, the surgeon may decide to fill the cavity inside the femur with bone grafts. In some cases, metal wedges may be used to strengthen the attachment of the new femoral component.

After the new femoral component has been glued in place with bone cement, the old implant in the tibia is removed and the bone is reshaped to receive a new implant. If the old implant had loosened because it had moved downward into the softer tissue inside the tibia, the surgeon will pack the space with morselized bone from a donor before putting in the new implant. This technique is known as impaction grafting. The impaction grafting may be reinforced with wire mesh. If the tibia has been shortened by the removal of damaged bone, the surgeon will insert a wedge along with the new tibial implant and secure them to the end of the tibia with bone cement. A new plastic plate will be fastened to the tray at the top of the tibial implant so that the patient's femur can move smoothly over the tibia. If the patient's patella (kneecap) has been damaged, the surgeon will resurface its back surface and attach a plastic component to protect the patella from further bone loss. The tibial and femoral components of the prosthesis are then fitted together, the kneecap is replaced, and the knee tendons reattached with surgical wire. The knee joint is washed out with sterile saline fluid and the various layers of the incision closed.

Revision surgery on an infected knee requires two separate operations. In the first operation, the old prosthesis is taken out and a block of polyethylene cement known as a spacer block is inserted in the joint. The spacer block has been treated with antibiotics to fight the infection. The incision is closed and the spacer block remains inside the patient's knee for about six weeks. The patient is also given intravenous antibiotics during this period. After the infection has cleared, the knee is reopened and the new revision prosthesis is implanted.