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Assessing the Risks

Learn about the risks of knee-replacement surgery before deciding if it's right for you

by: Karen Westerberg Reyes | from: AARP The Magazine | March/April 2010 issue

Any operation, no matter how minor, comes with risk. Knee-replacement surgery has its own catalogue of problems that can arise. These include:

Blood Clots

A clot in the leg is a minor problem, but if it travels to the heart or lungs, it can be life threatening. For this reason, blood-thinning medication, compression of the calf with surgical stockings, and special leg exercises are normal post-op therapies.

Infection

The consequences of infection after joint-replacement surgery can be very serious. In some cases, the prosthesis has to be removed in order to treat it. For this reason, special attention is given to keeping bacteria from entering the open wound, starting with precautions in the operating rooms. Antibiotics are routinely administered for a 24-hour period to all patients undergoing replacement surgery. Joint-replacement patients need to be vigilant about getting treatment for any infection anywhere in their bodies for the rest of their lives. In addition, they will need to take antibiotics before and after any dental work.

Loosening

One of the major long-term problems with artificial joints is separation of the area where the metal or cement meets the bone. When this happens, a revision (surgical repair of the damage) may be necessary. How long the bond lasts depends on how well the surgery was done in the first place (choose an experienced surgeon), how hard your bones are (osteoporosis can be a negative factor), how active you are (running and heavy lifting need to be avoided), and your weight (every extra pound adds three pounds of force to the knee).

Loss of Motion

In some cases, the knee is not able to bend normally after a knee replacement. For a person to do things like rise from a chair, the knee must be able to bend at least 90 degrees. Most post-op physical therapies aim for 115 to 120 degrees, but if the knee didn't bend at least 90 degrees before surgery, it's unlikely it will do so after. Consequently, patients might have difficulty doing some simple activities like kneeling, bending, and the like.

Nerve Damage

Skin around the knee will initially feel numb because small skin nerves were cut during surgery. This is a common occurrence, and sensation usually returns to some degree within a few months.

Osteolysis

This term means "breakdown of bone," a process that may happen over the years as tiny particles of worn-out plastic from the insert cause some of the body's own cells to damage the bone around the prosthesis. If left untreated, it could lead to the need for revision. Annual x-ray follow-ups are highly recommended to detect any osteolysis in time for treatment.