Scientific American Health Alerts Guide to Knee Replacement

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Weighing the Pros and Cons of Knee Replacement Surgery

Knee replacement surgery is not a quick fix, and it is not without risks. Serious complications, such as blood clots and infections, can occur—but precautions can be taken to prevent or control them. In addition, the road to recovery can be difficult and time consuming, particularly with joint replacement surgery. But many people who undergo knee replacement surgery experience decreases in their pain as well as significant improvements in psychological well-being and quality of life. Despite the risks of surgery, the expense, and the substantial commitment of time re­quired for recovery, the potential rewards for your physical and mental health are great.

Many people put off having knee replacement surgery, even when their doctor has assured them that surgery is an appropriate option. Often they feel their pain isn’t bad enough to warrant joint repair. But studies show that waiting until your pain and loss of function are substantial can make joint surgery more difficult and reduce your chance of re­gaining good function. One good reason for postponing surgery, however, is obesity. Although joint replacement surgery is effective in the majority of people who are obese, being obese does make the surgery more risky.

A recent survey showed that even though recovery can be long and sometimes painful, 82% of people who have this kind of surgery are very or completely satisfied with the results. In general, knee replacements last at least 10 years, and newer ones may last 20 to 25 years or longer.

Significant complications occur in about 40% of people who undergo joint replacement surgery. The most frequent is blood clots in leg veins. Surgeons take precautions to prevent this by prescribing blood thinners, such as aspirin or heparin, and using leg compression equipment (typically an air pressure device that repeatedly inflates and deflates to massage the leg and keep blood flowing).

A potentially more serious but less common complication is infection in the surgical wound or in the joint. Most infections can be treated with antibiotics, but infections deep in the joint may require removal of the prosthesis. Eventually, your surgeon can reimplant a new prosthesis. Individuals who have an arthroplasty have to guard against infection for as long as one to two years after surgery by taking oral antibiotics for even small infections and before dental work or urinary examinations. However, with preventive measures, the infection rate is no more than 3%.

More on Knee Replacement Surgery

What Happens During Knee Replacement

Joint replacement is called arthroplasty, and the most common type of arthroplasty is total joint replacement. In this procedure, the entire diseased or damaged knee joint is removed and replaced with an artificial one (a prosthesis) to relieve pain and restore function.

Is Age an Obstacle to Knee Replacement Surgery?

Some people may worry that they are too old too benefit from having a total knee replacement. But even osteoarthritis patients 75 and older appear to benefit greatly from joint replacement surgery, as a study in the Archives of Internal Medicine has indicated. Researchers followed 174 elderly patients with severe knee or hip osteoarthritis—average age 75—for 12 months, assessing them at six weeks, six months, and one year.

Minimally Invasive Knee Replacement Surgery

Surgeons continually seek ways to make joint replacements and repairs easier, safer and less arduous for the patient. A number of new techniques are currently under development.

Female Knee Replacements

Designed specifically to fit a woman’s knee, female knee replacements have been available only in recent years. Prior to 2006, when the Gender Solutions knee was approved by the U.S. Food and Drug Administration (FDA), knee replacements were unisex—designed to fit both men and women.

After Knee Replacement Surgery: Rehab and Recovery

Successful knee replacement requires a considerable investment of time and energy in rehabilitation following the surgery. Rehabilitation begins in the hospital, usually the day after surgery. During this period, a strict timetable of exercise, rest, and medication is crucial to the success of the surgery.

Resuming Physical Activities After Your Knee Replacement

If you are facing a knee replacement or have had one, you should talk to your physician about the risks of physical activity, such as a loosening or dislocation of the replacement and the possible need for a repeat surgery. Chances are, though, that a knee replacement won’t halt your golf game or drive you from the bowling lanes.


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