If you are considering a knee joint replacement, understanding in advance the lifespan of the prosthetic knee is important. The artificial knee joint is made of metal alloys, high grade plastics and polymers. The lifespan of an artificial knee varies based on certain specific criteria, including your gender and bone density.
Consideraitons
Knee replacement is a major decision. How long will you be out of commission, how much pain will you have to face, will you get relief of your knee problems that led you to surgery but, perhaps most importantly, how long will your knee replacement last? The lifespan that can be expected from an artificial knee joint is based largely on the same criteria that affects your natural knee. According to the American Academy of Orthopedic Surgeons, an artificial knee can last more than 20 years. Its longevity is based on the type of implant, in addition to your activity level, your weight and your health in general.
Anatomy
The AAOS suggests that most knee replacements performed today are cemented in to place. The longevity of the knee replacement is determined by the ability of the bones in your leg to absorb additional stress. If the loads are heavier due to activity or to weight that is more than your bone can bear, the prosthesis will loosen from its attachment to the bone. Women with bone density loss may experience this problem sooner than men. If you apply uneven loads to your knee due to your gait or another reason, only one side of the joint may loosen. When this occurs, the polyethylene liner between the metal parts can release particles that can trigger a biologic response that hasten the loosening of your joint. Excessive wear, your weight and even your gender can reduce the lifespan of your knee joint replacement.
Inflammation
Just as in your natural knee, the prosthesis and the bone it is attached to will be affected by tissue inflammation surrounding it. As the prosthesis begins to wear, microscopic particles are released which the cells in the tissues surrounding your knee recognize as foreign. This triggers an inflammatory response as your body tries to remove the debris. The inflammation attacks your bone and as you loose bone cells, your prosthesis can become loose and unstable. Inflammation, anatomy, your weight and activity level all play a part in the lifespan of your prosthetic knee.
Tips
If you have a knee replacement, you need to understand that the relief of pain in your knee is not a green flag to begin exercises or sports you were unable to do previously with your damaged knee. Your new knee does not make you bionic. Twisting and hard landings are particularly dangerous to your new knee -- just as they are to a natural knee. Low impact exercises such as walking, cycling, swimming, golf, bowling and yoga will help prolong the lifespan of your knee replacement. Surgeons warn against activities such as football, soccer, jogging or basketball because they increase the stress on your knee. Treating your new knee carefully will help prolong its lifespan.
