Now women facing knee replacement surgery can choose an implant designed to fit the narrower shape of their knees and offer greater flexibility and comfort.

According to Consumer Reports, more than 600,000 people in the United States have hip or knee replacement surgery each year, 70% of them because of osteoarthritis. One survey showed that even though recovery can be long and sometimes painful, 82% of people who had this kind of surgery were very or completely satisfied with the results.

Women account for nearly two-thirds of the knee-replacement procedures performed each year. These artificial knees have functioned well for both men and women. The anatomy of a woman’s knee, however, does differ in some ways from a man’s. Called the Gender Solutions High-Flex Knee, a women-specific knee implant addresses these differences.

Women’s knees are narrower from side to side and are shaped more like a trapezoid than a rectangle (the shape of a man’s knee). The bone in the front of a woman’s knee also is less prominent than a man’s. As a result, according to the manufacturer (Zimmer, Inc.), a conventional artificial knee may feel bulky to a woman. In addition, the angle between the pelvis and the knee is different in men and women. This can affect the way the usual artificial kneecap tracks over the end of the thighbone and may give a woman an unnatural feeling as it moves.

The Gender Solutions knee also has a high degree of flexion (up to 155 degrees), which may make movements like stair climbing easier. It’s important to note that this new knee is just one more option for women who need a knee implant. At this point, there is no actual scientific evidence that it is superior to other types of artificial knees when implanted in women. [This information was reported by the Food and Drug Administration, May 2006.]