If your orthopaedic surgeon has determined you need revision knee surgery, it is most likely because your knee has unrelieved pain and X-rays show damage has occurred to the knee replacement, causing its failure. The purpose of this procedure is to remove your failed implants, and replace them with new ones, which will help make your knee strong, stable and flexible again.
Approximately 45,000 revision knee replacement surgeries are performed in the United States every year, and new advanced technologies have made this a safe and effective way to restore the function of your joint.
While your knee implant may shift slightly after surgery, thus leading to unbalanced weight distribution and premature implant failure, the most common reason for knee implant failure is the wearing down of the plastic insert.
In the years following your first knee replacement surgery, the metal portion of your implant slowly wears down this plastic portion. In fact, your regular daily activities may produce as many as 2 million cycles per year on these parts.
Depending on the amount of wear to this plastic piece, your surgeon may be able to replace only the plastic piece alone. In other cases, though, you may have worn through it and damaged the metal components as well. In this case the entire implant will be replaced.
The wearing down of the plastic component has an unfortunate side effect. The tiny plastic particles that wear off are attacked by your body’s immune system, and this immune response also attacks the healthy bone around your implant. This leads to a condition called osteolysis, in which the bone in the area around the joint implant softens as it is absorbed by the body, thus making your implant unstable and in need of revision. Your orthopaedist usually will be able to detect osteolysis on your standard X-rays.
If the bone next to your primary implant is fractured in an accident, revision surgery may be required in order to provide a safe, stable joint. In this case, the original implant may need to be removed, the fracture addressed and a revision joint implanted.
In a low percentage of cases, your knee may become infected after surgery. Although it may be successfully treated with antibiotics, there are severe cases where a follow-up revision surgery may be required. In this surgery, the primary implants will be removed; and temporary, antibiotic-laced spacers are implanted. These spacers allow for joint function and are intended to give your body time to heal before the new revision prostheses are surgically implanted. Most likely, you will be put on a six-week course of antibiotics in order to eliminate the infection. At a follow-up evaluation, your surgeon will determine if your body is ready for the revision procedure.
Some questions you probably are thinking about are: what kind of implant device you will be receiving, what is it made of, and why is your surgeon using a particular kind of device? If you haven’t discussed this with your surgeon, you should, because not all knee implant devices are made of the same material.
In revision knee surgery, the prosthesis is made up of four parts. The tibial component has two elements and replaces the top of the shinbone (tibia). This prosthesis is made up of a metal tray attached directly to the bone and a plastic spacer that allows the thighbone to move over the shinbone. The femoral component replaces the bottom of the thighbone (femur). This component also replaces the groove where the knee cap (patella) sits. The patellar component replaces the undersurface of the knee cap, which rubs against the thighbone. The knee cap protects the joint, and the resurfaced patellar component slides smoothly on the front of the joint.
The information listed on this site is for informational and educational purposes and is not meant as medical advice. Every patient's case is unique and each patient should follow his or her doctor's specific instructions. Please discuss nutrition, medication and treatment options with your doctor to make sure you are getting the proper care for your particular situation.The information on this site does not replace your doctor's specific instructions.