A knee implant promising to give patients a wider range of motion is at the center of a public falling out between Zimmer Holdings and one of its top orthopedic surgeon consultants.
Richard Berger, MD, of the Rush University Medical Center in Chicago has been designing tools and implants, training doctors and promoting products for Zimmer for more than a decade, earning more than $8 million in payments for his consulting services, reports the New York Times. But the relationship began to turn sour in 2006, when Dr. Berger brought his concerns about the NexGen CR-Flex artificial knee to the company.
Rather than take his worries public, Dr. Berger first sought to study the problem with a colleague when Zimmer was unresponsive to his concerns, the Times recounts. Results showed an uncemented version of the knee, which is supposed to naturally fuse with the bone, failed early in about 9% of the 100 patients studied, and showed signs of loosening in about half the patients.
Dr. Berger and his co-author, Craig J. Della Valle, MD, presented their findings at a meeting last fall and this year at the American Association of Orthopaedic Surgeons meeting. But Zimmer did not back down, claiming that the knee had positive results among a large group of patients in Australia. The company did not give Dr. Berger a new contract last year.
Experts cited in the Times story note that the falling out between Dr. Berger and Zimmer highlights the lack of independent, unbiased information about orthopedic implants, since there is no system of tracking the performance of artificial hips and knees in the United States.
"There is no way of knowing who is right because we don't have the data," says Kevin J. Bozic, MD, professor of orthopedic surgery at the University of California, San Francisco.
Irene Tsikitas
