Dear Doctor Column, October 14, 2002

Question:

I am a 58-year-old female with a 40-year history of degenerative joint disease. My left knee is particularly problematic. My doctor says that I am "too young" for a knee replacement. What can you tell me about an FDA-approved device called the UniSpacer that can be implanted arthroscopically?

Answer:

Degenerative joint disease – better known as osteoarthritis or "wear-and-tear" arthritis – is the most common form of arthritis in the U.S., affecting approximately 20 million people, mostly after age 45. Osteoarthritis can range from mild to severe, affecting hands and weight-bearing joints, such as the knees, hips and feet.

Osteoarthritis is characterized by the breakdown of the joint's cartilage, which is the part of the joint that cushions the ends of bones. The roughened cartilage surfaces grind against each other causing pain, swelling, and stiffness. Eventually, the cartilage surfaces will completely wear away until bone is exposed.

Although age is a risk factor for osteoarthritis, research has shown that the disease is not an inevitable part of aging. Obesity contributes to osteoarthritis of the knees and hips, and people with joint injuries due to sports, work-related activity or accidents are at increased risk for the condition. Genetics also plays a role in the development of osteoarthritis, particularly in the hands, and women are more commonly affected than men.

The primary, long-term solution for individuals with severe knee pain has been knee replacement surgery, which involves replacing the damaged knee with an artificial implant. Some surgeons are reluctant to perform replacement surgery on younger, more active individuals, because of the irreversible removal of bone required. Currently, however, most surgeons consider patients age 40 and older potential candidates for replacement surgery.

According to the manufacturer, Sulzer Orthopedics, Inc., the UniSpacer was developed for individuals who have exhausted traditional treatments for knee pain, including drugs and arthroscopy, and are looking for an alternative to knee replacement. The device is designed to be implanted in the arthritic knee to restore the stability and alignment of the knee and relieve pain, thereby delaying or perhaps avoiding the need for a total knee replacement.

Unlike a total knee replacement, the procedure to implant the UniSpacer involves no cutting of the patient's bone and no cementing of the implant in the knee. The device is inserted through a small incision in the knee; it then centers itself in the knee, requiring no alteration of the surrounding bone or soft tissues. The surgery takes about an hour to complete and usually requires only an overnight hospital stay versus the three- to four-day hospital stay required by a total knee replacement.

According to the manufacturer, more than 400 people in the U.S. have received a UniSpacer, which was cleared for use in the U.S. by the Food and Drug Administration in January 2001.

For more information about the UniSpacer, call toll-free 88U-SPACERS. (888-772-2377).