Some people who have arthritis on only one side of a knee are now choosing to have a partial knee replacement instead of replacing the entire joint.

Arthritis of the knee, which is the wearing away of the cartilage that covers the bones in the joint, usually starts on the inside of the knee. Replacing just that inside portion can have several advantages, according to Dr. Jason Guevara, of Pinehurst Hip and Knee Center.

"Patients typically have half as much pain and recover twice as fast," Guevara says. "This is the least invasive of all joint replacements. I have seen patients throw away their canes in as little as three days after surgery."

Partial knee replacements often allow patients to move more naturally and to have greater range of motion. In some patients, a partial knee can prevent or postpone the need for a total knee replacement.

Guevara says partial knees have been available for about 40 years. Until recently, however, they weren't designed to allow for smooth, wide-ranging motion, and they had a success rate of only 70 to 80 percent.

By contrast, about 92 percent of total knee replacements are still working properly after 15 years.

"I had wanted to do partial knees for a number of years, but I didn't like the 70 to 80 percent success rate," Guevara says. "Now there is a new partial knee that has a success rate that is identical to the total knee."

The new device, developed by Biomet Orthopaedics, is called the Oxford partial knee implant. Unlike older types of partial knees, the Oxford has moveable plastic bearings that act as cushions, reducing wear and allowing for smoother, more natural movement.

"If you want to keep the maximum range of motion in your knee, then the Oxford is the gold standard," Guevara says.

Only a small number of people with arthritis in one or both knees are good candidates for a partial knee replacement. One of those was Dr. David DuBois, an emergency department physician at FirstHealth Moore Regional Hospital. He had arthritis on the inside of his right knee.

Last July, Guevara removed the affected portions of bones in DuBois' joint and implanted an Oxford partial knee. DuBois, who is 52, was in the hospital for two and a half days. He returned to work six weeks later.

"I was up and about very quickly," he says. "The first day home, I used a walker. The second day, I used a crutch. After that, I only needed a cane."

As part of his rehabilitation, DuBois went to the FirstHealth Center for Health and Fitness for aerobic exercises and strength training. He also exercised at home.

"I am now pain-free and have normal use of my knee," he says. "I don't limp, and I can get up out of a chair and go up and down stairs without holding on to anything."

That is important for anyone, especially for emergency department physicians who are on their feet a lot and are constantly moving between patients and computer work stations.

"When you are the only doctor there at night and you have 24 beds to cover, you are always up and down," he says. "You need to be able to move well and without pain."