Zimmer Durom Cup Hip Implant Recall
The Device
Since entering the market in 2006, the Zimmer Durom Cup has been implanted in over 13,000 patients nationwide, and was initially heralded as a major advancement in total hip replacement surgery. Specifically, the Durom Cup was designed with the intention of creating a device that would last longer, as well as fuse to the skeleton naturally as opposed to requiring screws. To achieve these ends, the ace tubular shell was coated with a porous material, allowing natural bone growth to occur into and within the shell, the result being a natural fusion between device and skeleton.
The Controversy
Since the release of the device, its safety and effectiveness have come into question based on data suggesting excessive failure rates, the suspension and eventual termination of sales, and lawsuits against Zimmer by both patients and shareholders. In 2008, Zimmer reported setting aside $69 million in anticipation of litigation[1].
In April 2008, Dr. Lawrence Dorr, a former consultant for Zimmer as well as an orthopedic surgeon with over 30 years experience, released the first adverse report detailing unacceptable failure rates associated with the device. Specifically, one year after implanting the device, 15% of patients required revision. Among the remaining population, an even greater number of patients exhibited signs of impending failure. According to the New York Times, Dr. Dorr disclosed this data with Zimmer but the company declined to take action until the results were made public by the American Association of Hip and Knee Surgeons[2]. In July 2008, Zimmer pulled the device from the market temporarily, and ultimately discontinued sales in 2010.
While Zimmer initially indicated in a follow-up study of their own design that up to 5.7% of implants would need to be replaced in the US and Europe, alternative investigations have suggested a higher rate of failure. The most recent study, conducted at the University of Wisconsin, compared outcomes following total hip replacement using two different devices one year after surgery. The data collected by the authors indicated that while none of the more modern alternative devices failed, the Durom Cup exhibited a striking 11% failure rate. Furthermore, patients with the failed device exhibited pain and discomfort indistinct from pre-operation levels[3].
In both the Wisconsin and Dr. Dorr studies, closer inspection of the failed device revealed an absence of proper fusion between cup and bone, suggesting design flaws. Consequently, the device can separate and migrate, pushing the metal hip socket against the bone to produce excruciating pain. As a result, the patient may require surgery, rehabilitation, and in-patient hospital monitoring.
Finally, recent evidence suggests that the metal-on-metal design of the device can lead to arthroprosthetic cobaltism, resulting in genotoxity and the potential for changes in the structure or integrity of genetic material in an organism[4]. The danger of this form of toxicity is that it can result in cancer, or if the damage occurs in reproductive cells, inherited disorders in offspring. Finally, as these metal ions are excreted through the kidneys, internal damage can be exacerbated in those with renal failure, or who are at risk of renal failure.
Symptoms
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Start up stiffness and pain when rising from a chair or getting out of a car after three months
post-operation -
Sharp groin pains when moving from bent to upright positions or when lifting the leg straight up
when lying down -
Difficulty climbing stairs
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Inability to walk distances
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Reliance on a cane when walking outdoors
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Behavioral effects associated with heavy metal poisoning
If you or a loved one have or had a Zimmer hip implant and have been diagnosed with any of the above, please contact Freese & Goss today.
[1] Zimmer Reports Fourth Quarter and 2008 Financial Results.
[2] Barry Meier, A Call for a Warning System on Artificial Joints, NY Times, July 29, 2008.