Surgeons Urge Recall Of Zimmer NexGen Knee Replacements

The NY Times reported earlier this year that a prominent orthopedic surgeon in Chicago has called for a recall of Zimmer NexGen artificial knees and knee replacement components – specifically, the Zimmer NexGen CR-Flex replacement knee.

For more than a decade, Dr. Richard A Berger not only installed Zimmer replacement knees into patients, he designed surgical tools and artificial joints for Zimmer Holdings, trained doctors across the country to use Zimmer products and promoted Zimmer where he went. Zimmer was pleased with Dr. Berger, having paid the master surgeon more than $8 million over the last 10 years.

Then Dr. Berger notified Zimmer that its NexGen artificial knee was defective and failing prematurely. Dr. Berger even published a study proving the defect in the Zimmer knee replacement.

Dr. Berger is not the only orthopedic surgeon concerned about defective Zimmer artificial joints. Dr. Lawrence Dorr in Los Angeles alerted Zimmer years ago that its artificial hip was failing after only a few years.

Zimmer blamed the defects and failures of its hip and knee replacements on the surgeons’ technique, rather than the artificial joints. However, Zimmer’s chief scientific officer previously praised Dr. Berger, saying "Rich has a very clever set of hands, and because of that he is enabled with the ability to innovate surgical techniques." Zimmer even hired Dr. Berger to train hundreds of orthopedic surgeons to use Zimmer medical devices and his technique was profiled on ABC’s World News Tonight.

Amid the booming use of artificial joints in the United States, the breakup between Dr. Berger and Zimmer highlights what experts say is a troubling situation for patients and doctors: when disputes arise about orthopedic implant safety, there are no independent referees or sources of information because no one tracks the performance of the devices.

"There is no way of knowing who is right because we don’t have the data," said Dr. Kevin J. Bozic, a professor of orthopedic surgery at the University of California, San Francisco.

Disturbingly, many artificial joints — including artificial knees and replacement hips — are cleared by the Food and Drug Administration (FDA) without testing in patients.

What’s Wrong With the Zimmer NexGen CR-Flex?

Many artificial knees rely on a cement-like adhesive to bond the thigh bone to the portion of the knee replacement that bends. However, many surgeons try to avoid adhesives because the adhesive can break down, leading to device failure. Because of the preference, Zimmer sells an uncemented version of the CR-Flex that relies on the bone to naturally fuse with the knee implant.

According to the Times report, Dr. Berger implanted the device into 125 patients in 2005. By early 2006, X-rays revealed lines where the implant met the thighbone, meaning the knee implant was loose and not completely fused. Patients were experiencing pain due to the loose artificial joint. Dr. Berger reported the problem to Zimmer, but the company did not have adequate data because Zimmer did not test the device in patients before selling it.

Dr. Berger and a colleague from Rush University, Dr. Craig Della Valle, performed a study finding that the uncemented Zimmer knee failed in 9% [update: 8.3% (9 out of 108)] of patients studied.

Potential complications include:

• Knee Replacement Failure
• Revision or Replacement of Artificial Knee Device
• Loosening of Replacement Knee Implants
• Knee and Joint Pain
• Difficulty Standing or Walking

Senate Investigation

After the NY Times report on Zimmer knee problems, Republican Senator Chuck Grassley wrote to Zimmer, asking the company to disclose how the company tracked long-term performance of its orthopedic devices.

[Read Sen. Grassley’s letter to Zimmer here]

Medical Device Defects

There have been a number of defective medical devices in news lately — including the DePuy artificial hip recall and breast implants that may cause cancer.

While Dr. Berger has so far focused on the Zimmer NexGen CR-Flex knee, he is expanding his investigation to other Zimmer knee replacement devices as well — including those that use adhesive to bond the device to the femur. It is possible that other Zimmer artificial knees exhibit similar failure problems.

It is appalling that giant medical device companies would let surgeons put these medical devices in patients without any patient testing trials whatsoever. When medical device companies won’t act responsibility and regulators won’t hold them accountable, it is up to patients and the public to demand justice and make sure these defective products don’t hurt any more people.

More on the Zimmer Artificial Knee Problems:

• Surgeon vs. Knee Maker: Who’s Rejecting Whom? [Barry Meier at New York Times]
• Senator Seeks Data on Artificial Hips and Knees [Barry Meier at New York Times]
• Surgeons Challenge Zimmer to Pull High Flex NexGen Knees Off Market Because of High Loosening Rates [at OrthoStreams]
• Senator Asks Zimmer for Hip, Knee Data [at Medical Product Outsourcing]
• Sen. Grassley questions Zimmer on product complaints, performance tracking [at ORTHOSuperSite]
• Senator questions Zimmer about "safety concerns" [via BNET.com, the CBS Interactive Business Network]

(c) Copyright 2011 Brett A. Emison