Update on Hip and Knee Replacements

By Vrinda Suneja,M.D.
Medical Director
Fox Run

Increased viability of joint replacements, especially artificial hips and knees, is an area in which new technologies have had an impact. The American Academy of Orthopedic Surgeons (AAOS) notes approximately 761,000 hip and knee replacements are performed annually, with the average age of people ranging from 67 (for total hip replacements) to 80 (for partial hip replacements).

Joseph C. McCarthy, clinical professor of orthopedic surgery at the New England Baptist Hospital in Boston, Mass. says, “A general trend toward less invasive surgery is especially good for older Americans, helping them to resume function and return to living independently as soon as possible.”

Besides being less invasive, there are two other improvements in today’s procedures that benefit older adults. “Better pre-op medical screening and improved anesthetics can improve post-op complications to people with coexisting medical problems, such as heart conditions, diabetes, and high blood pressure,” says McCarthy.

New Materials Increase Hip Longevity
Hip replacements, usually spurred by severe arthritis, are the most commonly performed joint replacements. Perhaps one of the greatest advances in hip replacements is the improved materials surgeons now have. A hip replacement usually consists of two components: a rounded socket that becomes part of the pelvis, and a ball on a stem that fits inside the upper part of the thigh bone. Together, the two allow hip motion.

For years, the most common hip joint components were a plastic socket and a metal ball and stem combination. They generally lasted about 10 or 15 years. Today, there are combinations more resistant to wear.

“We have tougher polyethylene plastic, metal-onmetal, and ceramic-onceramic combinations.” Thanks to such improvements, the lifespan of artificial hips has doubled, although the longevity of newer materials is still being evaluated.