June 2007 | Back to Table of Contents

Pulse

Tracking Implants

Mayo Clinic is home to the world's most comprehensive collection of joint replacement data.

In early April, Mayo Clinic orthopedic surgeon Bernard Morrey, M.D., got a call from a colleague in Texas whose patient had Paget’s disease and needed a hip replacement.

The Texas doctor wondered whether or not he should use cement to affix the prosthetic joint to the bone.

Morrey didn’t know the answer offhand, but he was pretty sure he could find it. To seek it out, he turned to the Mayo Clinic Joint Replacement Database, a repository of information about every knee, hip, shoulder, wrist, ankle, finger, and elbow replacement performed at the clinic since 1969, the year Mayo orthopedic surgeon Mark Coventry, M.D., performed the first FDA-authorized total hip replacement surgery in the United States.

The most comprehensive collection of information on joint replacements in the world, the database has more than 80,000 entries. About 35,000 of them are hip replacements, and about 24 of those hip surgeries were done on patients with Paget’s disease. Morrey’s search showed that the outcomes of the surgeries were similar regardless of whether or not the surgeon used cement to bond the implant. “There is no way that someone could investigate the literature and get an answer to that specific of a question,” he says.

Designing Data
In 1988, Morrey, former chair of orthopedics at Mayo, saw the potential of the joint replacement registry and wanted to beef it up. In addition to basic information such as a patient’s name, age, weight, underlying diagnosis, and reasons for selecting a particular type of implant, he also wanted outcomes data. So they retroactively added details and began capturing such information going forward.

Today, the database includes specifics about a patient’s level of pain before surgery, joint function, exam findings, and the type of implant received. This allows researchers to calculate function and evaluate a patient’s subjective view of his or her status before and after the procedure.

By 1990, doctors were using the registry to answer questions such as whether hip replacements fail more in older patients than younger ones (they don’t) and whether men or women tend to wear out joints faster (men do).

Answers to such questions don’t come easy, Morrey says. He explains that it costs hundreds of thousands of dollars to pay staff and keep the computers that house the database running. Postoperative patients are contacted one year, two years, and then every five years after receiving their implant and encouraged to return to Mayo for an assessment and to complete a questionnaire or be interviewed by Mayo staff about their experience with the new joint. This has allowed Mayo to capture follow-up information on 95 percent of joint-replacement patients.

Daniel Berry, M.D., chair of the department of orthopedic surgery at Mayo, says the database is crucial to furthering medical knowledge. For example, during the 1980s and ’90s, surgeons began to do knee replacement surgeries without cement. Evidence from the database showed that those replacements didn’t hold up as well as ones done using cement.

Over time, the database provides insights similar to those of a long-term study. Says Berry: “This provides you with a very scientific way of determining if what you are doing is successful, not only in the short term, but also in the long term.”—Scott D. Smith