Spring 2008

Demands on Joints, Demand for Joint Replacements

Joint replacement is becoming increasingly common. For instance, surgical teams now perform more than 400,000 hip joint replacements each year in the United States on patients whose joint pain compromises mobility and activity, and whose pain persists despite treatment. No end to the joint replacement boom is in sight.

"We used to see primarily patients in their 60s and 70s," says Thomas Parker Vail, M.D., chair of the Department of Orthopaedic Surgery at UCSF Medical Center. "We replaced their joints to manage their pain. But because of the success of the surgeries and the durability of the artificial joints, we're now seeing more and more patients in their 50s and even 40s." But patients in their 80s also are among those who are increasingly seeking joint replacements to stay active, Vail notes.

Vail and his fellow surgeons at the UCSF Arthritis and Joint Replacement Center— Michael Ries, M.D., Harry Jergesen, M.D., Kevin Bozic, M.D., MBA, and Alfred Kuo, M.D., Ph.D.—are experienced in computer-assisted surgery, less invasive hip and knee replacement, unusual and complicated cases, and high-demand replacements for younger, more active patients. They also provide joint resurfacing when appropriate.

Despite the routine nature of many joint replacements, improvements in implants and procedures still have the potential to reduce both short- and long-term failure and complications, Vail says. "We don't have the data to know whether a 40-year-old with total hip replacement or hip resurfacing will be able to remain highly active and never expect a revision." The most recent data suggest that the number of repeat surgeries for hip replacement is holding steady—between 5 percent and 10 percent of patients will need a revision within 20 years.

As a short-term consideration, many patients are drawn to minimally invasive joint replacement surgery by the promise of faster recovery times. However, the size of the incision is just part of the story when it comes to patient recovery. To a greater degree, the faster, easier recoveries made possible over the last decade are due to a combination of improvements in surgical technique, pain management and rehabilitation therapy, Vail says.

All members of the medical team at UCSF—including patient education specialists and physical therapists—are specifically trained in joint replacement, which helps ease the transition into surgery and through recovery.

In clinical studies, the UCSF surgeons are evaluating joint replacement outcomes, methods to improve function and reduce complications, and the etiology and treatment of osteonecrosis of the hip. Their analyses have led to many scientific publications and invited presentations around the world. Among the many topics that this group has studied, the performance of implants with porous metal surfaces for bone ingrowth or bone cement for solid initial fixation has immediate relevance to patients.

"The cemented total knee replacement is still the state of the art," says Ries. "There have been some recently developed new materials for cementless knee replacement that are still being evaluated. But cementless knee replacement has not worked as well over the long haul as cemented knee replacement. That is in contrast to hip surgery, where the cementless hip stems seem to be performing better than the cemented hip stems."

One of Bozic's research interests is in evaluating the value of new orthopaedic technologies from a societal perspective. "Many new technologies look very promising based on laboratory results, but do not always perform as well under less than ideal conditions when implanted in patients. It is important for us to understand the clinical, economic and societal impact of new technologies both before and after they are introduced into the marketplace."

In a recent study regarding the cost-effectiveness of computer-assisted surgical navigation in total knee arthroplasty, Bozic and his colleagues found that under certain circumstances, computer navigation could be considered both cost-saving and more effective than conventional techniques for total knee arthroplasty.

In lab studies of hip replacement design, Vail is experimenting with the use of large-diameter metal bearings. The larger bearings are designed to lower the risk of dislocation, and also to reduce wear on the joint by achieving better fluid-film lubrication between ball and socket. Vail also is developing new implant designs that will do a better job of loading bone in a natural way, helping to maintain bone strength and reduce the risk of fractures.

The UCSF Arthritis and Joint Replacement Center was awarded a three-star rating for quality and excellence in patient care from United Healthcare in 2007, and is internationally recognized in continuing education.

Who Should Be Referred?

Good candidates for referrals to the UCSF Arthritis and Joint Replacement Center include patients:

  • Who have persistent pain in their hip or knee for more than six months that is not responsive to medical management (including injections, nonsteroidal anti-inflammatory medications and physical therapy)
  • Who have been diagnosed with arthritis of the hip or knee

UCSF Arthritis and Joint Replacement Center surgeons can be contacted at (415) 353-2808.

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