Knee revision surgery, which is also known as revision total knee arthroplasty, is a procedure in which the surgeon removes a previously implanted artificial knee joint, or prosthesis, and replaces it with a new prosthesis. Knee revision surgery may also involve the use of bone grafts. The bone graft may be an autograft, which means that the bone is taken from another site in the patient's own body; or an allograft, which means that the bone tissue comes from another donor.
If your hip has been damaged by arthritis, a fracture, or other conditions, common activities such as walking or getting in and out of a chair may be painful and difficult. Your hip may be stiff, and it may be hard to put on your shoes and socks. You may even feel uncomfortable while resting.
Knee revision surgery has three major purposes: relieving pain in the affected hip; restoring the patient's mobility; and removing a loose or damaged prosthesis before irreversible harm is done to the joint. Knee prostheses can come loose for one of two reasons. One is mechanical and is related to the fact that the knee joint bears a great deal of weight when a person is walking or running. It is unusual for the metal part of a knee prosthesis to simply break. This part, however, is inserted into the upper part of the tibia, the larger of the two bones in the lower leg, after the surgeon has removed the upper surface of the tibia. The bone tissue that receives the metal implant is softer than the bone that was removed, which means that the metal implant may sink into the softer bone and gradually loosen.
The second reason for loosening of a knee prosthesis is related to the development of inflammation in the knee joint. The plastic part of a knee prosthesis is made of a material called polyethylene, which can form small particles of debris as a result of wear on the prosthesis over time. If the patient has an uneven gait, or pattern of walking, the debris particles tend to form at a faster rate because one side of the prosthesis will tend to pull away from the bone and the other side will be pushed further into the bone. These tiny fragments of plastic are absorbed by tissue cells around the knee joint, which become inflamed. The inflammatory response begins to dissolve the bone around the prosthesis in a process known as osteolysis. As the osteolysis continues, bone loss accelerates and the prosthesis eventually comes loose.
A knee prosthesis that has become infected or completely dislocated must be removed and replaced to prevent permanent damage to the patient's knee.
Post-traumatic arthritis. Although no revision surgery is easy or simple, there are different kinds of revisions. Sometimes only some of the parts need to be replaced and in other cases, all the parts need to be removed and the bone around the knee needs to be re-built with artificial bone. Below are a few examples of revison knee replacements:
The complications that may follow knee revision surgery are similar to those for knee replacement. They include:
1. Deep vein thrombosis.
2. Infection in the new prosthesis.
3. Loosening of the new prosthesis. The risk of this complication is increased considerably if the patient is overweight.
4. Formation of heterotopic bone. Heterotopic bone is bone that develops at the lower end of the femur following knee replacement or knee revision surgery. Patients who have had an infection in the joint have an increased risk of heterotopic bone formation.
5. Bone fractures during the operation. These are caused by the force or pressure that the surgeon must sometimes apply to remove the old prosthesis and the cement that may be attached to it.
6. Dislocation of the new prosthesis. The risk of dislocation is twice as great for revision surgery as for TKR.
7. Difference in leg length resulting from shortening of the leg with the prosthesis.
8. Additional or more rapid loss of bone tissue.