Volunteers bequeath artificial joints to lab

CHICAGO -- It may seem slightly impolite, but doctors at one Chicago hospital routinely ask patients with artificial knees and hips if they wouldn't mind returning their joints when they're done with them.

Post-mortem studies can tell researchers a lot about how prosthetic joints wear down or stay strong over time, said Dr. Joshua Jacobs of Rush University Medical Center. Jacobs and his colleagues hope their work can help build longer-lasting joints for the more than 400,000 Americans who have joints replaced each year.

So far, the orthopedic implant retrieval laboratory at Rush has retrieved 189 joints from 115 patients after death. Another 740 patients have signed up.

"It's amazing how many people are willing to be a part of this," Jacobs said. "They think of it in a positive way, how this research can be used to help mankind."

The unusual brand of volunteerism often stems from gratitude, Jacobs said. Patients want to help the orthopedic surgeons who restored their ability to walk without pain.

Harriet Daniels of Naperville is one of the volunteers. Discomfort from osteoarthritis drove her to have four joint replacement surgeries, one each decade starting with her left hip in 1978. She had her right hip done in 1985, her left knee in 1994 and her right shoulder in 2002.

When the Rush hospital staff told her about the post-mortem retrieval study, she agreed to take part. Studying her joints could be a short course in the modern history of joint replacement.

"It's a mighty easy way to help science," said Daniels, 85.

Since the program began in 1990, it has retrieved 112 hips, 69 knees and eight other devices, such as shoulders. The research is part of a broader study on joint replacement, said Laura Quigley, a registered nurse who participates in the program.

A retrieval team is always on call and ready to act quickly so the procedure doesn't delay funeral plans. The team brings its own surgical instruments, collection containers and protective gear. There is no cost to the family.

When Mayer Stern died April 2, 2005, at age 85 in Miami, his widow, Gloria Stern, knew he had wanted to participate in the joint retrieval program.

"I remembered. My daughter remembered," Gloria Stern said. "It was common knowledge among our family that he was going to be cremated and those particular remains would go to Rush hospital."

After the family informed Rush of Stern's death, the implant retrieval lab and the Florida funeral home staff discussed logistics, including how Stern's two artificial hips would be transported to Chicago.

The lab staff found a pathologist who could retrieve the joints according to the hospital's instructions, pack them into specimen collection containers and ship them under refrigeration to Rush.

"It went very, very smoothly. We were able to still have the services the family requested and there were no interruptions. The family was ecstatic this could be done," said Hara Ahrens, funeral director at Riverside Gordon Memorial Chapel in Miami Beach, Fla.

"I found knowing his wishes, and having it taken care of, very comforting," Gloria Stern said. "He sort of looked forward to the idea he could do something after his death."

Failing artificial joints that must be replaced during a patient's lifetime also are retrieved and studied. But post-mortem retrieval is the only way to study joints that worked well enough to outlast the patient, Jacobs said.

"In addition, the studies done post-mortem allow us to retrieve not only the implant but also the surrounding tissues," Jacobs said. "That gives us much more insight into how the surrounding tissues have been affected."

For example, researchers found that screw holes and uncoated surfaces are especially vulnerable to the migration of debris generated by wear and tear of the joint surfaces. This debris can activate the local immune response and cause bone loss and loosening of the implant. On the plus side, they've learned that human bone continues to grow into porous-coated surfaces, strengthening the joint, for years after surgery.

And the search is on for new wear-resistant materials that shed less debris that can migrate to a patient's lymph nodes, liver or spleen, Jacobs said. Researchers don't think migrated debris from artificial joints causes serious health problems, but they would like to reduce it.

The Rush program may lead to a wider effort to study retrieved implants. In 2002, the Food and Drug Administration and other federal agencies co-sponsored a two-day meeting on medical implants. Experts at the meeting recommended better tracking of how implants perform. Staff from the Rush program shared their procedures for retrieval.

The magnitude of the Rush program sets it apart from smaller efforts, said Dr. Regis O'Keefe, past president of the United States Bone and Joint Decade, an initiative to raise public awareness about bone and joint disorders.

"The ability of joint replacement procedures to improve the lives of people is extraordinary. At the same time, we don't completely understand the science behind it and how prosthetics materials interact with joint tissues and how we can improve them," O'Keefe said.