Mary Ann has had arthritis for years. Recently, her knees have ached more than ever, and the pain is affecting her ability to move around.

"Over many years, wear and tear from arthritis causes severe bone damage to the joints," says Dr. John Callaghan, professor of orthopaedic surgery at the University of Iowa College of Medicine and staff physician at UI Hospitals and Clinics. "Ten to 20 percent of all arthritic knee and hip joints will need to be replaced."

Before joint replacement is considered, Callaghan suggests other options including the use of anti-inflammatory medications such as aspirin or ibuprofen and natural substances such as glucosamine to ease pain and reduce swelling in the joints; using a cane while walking; and decreasing physical activity. Weight loss and gentle movement exercises such as water aerobics are also helpful.

"If these measures don't alleviate the pain, then joint replacement can be considered," Callaghan says. Nearly 250,000 joint replacements are done annually, with knees making up the majority, followed by hip replacements.

"A typical person who needs joint replacement is in his or her 60s and can no longer enjoy activities such as gardening or walking the dog. His or her daily life is restricted by arthritic pain. Joint replacement will help eliminate the daily pain the person experiences," Callaghan says. "However, because of our complex practice here at the university we see many patients age 20 to 60 who are good candidates for joint replacements."

The surgery for joint replacement involves shaving off the ends of the bones and replacing them with a joint made of metal and plastic, Callaghan says. Immediately after replacement, the person will stay in the hospital for five to seven days resting and participating in a physical therapy program.

"After knee or hip replacement, the person will use crutches for added support for six weeks, and then a cane until full recovery," Callaghan says. The success rate of joint replacement is 90 to 95 percent, and pain relief is excellent for at least 10 to 15 years. "Patients who have a joint replaced regain full mobility of the joint. Low impact exercise is fine, although high impact exercise like running is not recommended," Callaghan says.

People as young as 18 have received joint replacements. "It's important for young people to understand that they may require another replacement many years later, because the joint may wear out or loosen. But older persons have little reason to expect a second joint replacement," Callaghan says.