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Robert B. Bourne, MD Canadian Orthopaedic Association


Published 1/1/2011
Mark W. Wieting

Real-time, real-world data on hip and knee replacements

International joint registries—from Australia to the United States

Surgeons can draw their own conclusions about what joint registry data reveal, according to Steven Graves, MD, because registries neither interpret data nor make recommendations. Outcomes data obtained through registries, however, can help weed out lesser-performing devices and concepts.

An orthopaedic surgeon from Adelaide, Australia, Dr. Graves spoke at the Combined Orthopaedic Associations Meeting in Glasgow, Scotland. He and representatives of six other international orthopaedic associations provided updates on their countries’ joint registries.

In contrast to clinical trials data, registry data provide real-time and real-world information, Dr. Graves explained. Registries are not designed to establish causality, but rather to identify factors associated with differences among hip and knee implants being used. Based on his experience, “registries have been known to change practice in a positive manner,” he said.

Information in the Australian registry is delivered to orthopaedic surgeons confidentially through an online, automated, personalized audit, and includes patient deaths and revisions. It is also reported to hospitals, regulators, and industry.

The data invite comparisons among the implants, which benefit both patients and surgeons. Knowing how well or poorly implants perform is an “underutilized benefit” to the companies, he said, even though some companies have challenged the use of registry data to evaluate the performance of their products.

According to data from the Australian joint registry, which was established in 1999, revision hip procedures in that country have decreased as a proportion of all hip procedures—from 14.8 percent in 1999 to 11.2 percent in 2009. Similarly, revision knee procedures have decreased as a proportion of all knee procedures—from 10.4 percent in 1999 to 7.8 percent in 2009.

The New Zealand experience
According to Gary J. Hooper, MD, the New Zealand Registry, which was created in 1999, has now reached a 98 percent capture rate of all total hip and knee replacements. The registry is owned by the New Zealand Orthopaedic Association (NZOA), and participation is mandatory for all public and private hospitals as well as for all surgeons who perform hip and knee replacements. Under an act of Parliament, individual data is not discoverable in court.

The New Zealand Registry provides surgeons with their rates of revision as compared to the national average, which Dr. Hooper described as “powerful, unbiased outcomes data.” Under the NZOA Outlier policy, local peer review is used to help orthopaedists who have unacceptable revision or complication rates to improve their performance.

Difficulties in South Africa
Richard R. van der Jagt, MD, told a different story. Despite statements of support from the South African Orthopaedic Association (SAOA), the joint registry in South Africa had only 20 percent participation after 3 years. Moreover, the registry included only the most basic information—the type of implant and whether or not cement was used. No outcomes data were included.

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Robert B. Bourne, MD Canadian Orthopaedic Association
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Steven Graves, MD Australian Orthopaedic Association

Dr. Van der Jagt cited roadblocks from industry and a negative response from orthopaedic surgeons as the chief difficulties. Surgeons, many of whom have close ties to implant manufacturers, objected to the time and paperwork required to report their data. Although the SAOA is still committed to an effective registry with full compliance, the Minister of Health has not supported their efforts, and work on the registry has been suspended.

The Canadian registry
In partnership with the Canadian Institute for Health Information and with government funding, the Canadian Orthopaedic Association launched its registry in 2001. In this voluntary registry, patient consent is required for surgeons to submit data, according to Robert B. Bourne, MD. Approximately 70 percent of Canadian orthopaedic surgeons participate, but some do not report all of their patients; as a result, less than half of all joint replacement patients are included in the database. Dr. Bourne noted that satisfaction data and health-related outcomes are as important as revision rates, which he called “blunt outcomes tools,” and he believes that keeping the data simple and removing the patient consent requirement will increase participation.

Henrik Malchau, MD, PhD, discussed the joint registry just getting underway in the United States. The American Joint Replacement Registry (AJRR) has a goal of attracting 750 participating hospitals in its first year. It is governed by seven orthopaedic surgeons and six non-surgeons, including one public member, and funded through grants from the AAOS, the American Association of Hip and Knee Surgeons, the Hip Society, the Knee Society, insurance companies, and the orthopaedic industry.

An American registry has tremendous potential for helping to control healthcare costs, noted Dr. Malchau. For example, reducing the current revision rate for total joint arthroplasty among U.S. Medicare patients (19.6 percent) by just 1 percent is likely to yield cost savings of $50 million to $110 million annually.

The Scottish Arthroplasty Project
An administrative database run centrally by the Scottish government, the Scottish Arthroplasty Project focuses on patients more than implants, said Colin Howie, MB, ChB. Every patient receives a unique national identifying number and is followed through the system. Outlier cases are sent to the respective hospitals with a request for analysis and report.

Individual orthopaedic surgeon data is published anonymously, which allows poor performers to give up performing arthroplasty, change their techniques or implants, or retire. Not all outliers should be labeled poor performers, however, because they may take on extremely difficult cases.

England and Wales
Although a regional registry was begun in Trent in 1990, the failure of the 3M Capital Hip in 2001 spurred the establishment of a national joint registry in England and Wales in 2003, noted Paul J. Gregg, MD. The registry is funded by a £20 payment per prosthesis (about $31) and has data from more than 95 percent of the orthopaedic units in England and Wales—more than 905,000 hip and knee replacements, and more than 700 different cup/stem combinations. Dr. Gregg noted that one hospital was using 27 different femoral stems, but was able to reduce that number significantly by acting on registry data.

One of the benefits of the large number of cases in registries, according to Dr. Gregg, is that in the aggregate they provide data that is otherwise unavailable. A prosthesis that performs well in various registries may have a good design—or just be easier to use. Either way, the outcomes are better for patients.

According to Joshua J. Jacobs, MD, an orthopaedic researcher and current president of the U.S. Bone and Joint Decade, “Level one data from national joint replacement registries provide valuable insights into the survivorship of devices in a large, nonselected population of patients. However, data from carefully conducted, detailed prospective and case-control studies, which include level two and three data, provide complementary information. Findings from both sources should be used in concert to develop a more complete and in-depth characterization of the outcomes of joint replacement surgery.”

Mark W. Wieting is the AAOS chief education officer and can be reached at