June 18, 2014 - As aging baby boomers have sought over the past two decades to maintain active lifestyles, more and more metal-on-metal hip devices have been implanted. It was originally believed that the metal-on-metal hip implants were a perfect match for this older—yet more active than prior generations of this age—group of people. During the three decades from 1970 to 2000, hip implant devices were largely constructed of ceramic, polyethylene and metal-on-plastic, even though the technology for a metal-on-metal hip implant existed. The longest tried-and-tested hip was the metal-on-plastic, which worked remarkably well. Femoral stems were generally constructed of cobalt and chromium while the concave cup was made of polyethylene. The components were chosen for durability and performance and also happened to be the least expensive implant type.
The Beginning of All-Metal Hip Implants
All hip implants shed debris to some extent during times the patient engages in activity. Even so, a metal-on-plastic implant has a very low rate of wear, coupled with a high resistance. The ceramic implant also had good results, with one of the few noted issues associated with the implant being its tendency to make squeaking noises (which are so disruptive in some cases, that a revision surgery is necessary). Metal-on-metal hip implants, while used as far back as 1955, did not gain FDA approval until 1999. These all metal hip implants were pushed hard by the manufacturers, who claimed they would revolutionize the artificial hip industry by lasting as much as ten years longer than a more traditional implant.
What Portion of Hip Implants Utilize a Metal-on-Metal Device?
Nearly 300,000 hip implant surgeries are performed each year in the United States; in 2007, implantation of metal-on-metal devices peaked, accounting for over a third of all implants. Once the recalls began and patients began reporting adverse events related to a metal-on-metal hip implant, the number of all-metal implants has now dropped to 10% of the total or less. A 2011 report showed twice the number of revisions for metal-on-metal hip implants than for other types, including ceramic, polyethylene and metal-on-plastic. Surgeons began realizing that the all-metal hip implants were responsible for fretting, corrosion and the release of cobalt and chromium ions into the body.
The Necessity of Cobalt and Chromium Testing
While cobalt and chromium testing was not protocol in the early 2000’s, surgeons soon became alarmed when presented with symptoms of heavy metal poisoning and realized they must re-think their approach to patients with all-metal hips. All-metal hip implants still offer some benefits over more traditional devices such as a decreased chance of dislocation and a decreased chance of device fracture. When chromium and cobalt poisoning is not present, the all-metal hip may well last from 15-20 years, however metallosis and metal toxicity are serious issues associated with the devices.
Patient Selection Critical in the Implantation of All-Metal Hips
Patient selection is crucial to the success of the procedure—one orthopedic surgeon stated that metal-on-metal hip implants are truly indicated only for a limited number of patients, generally men, younger than the age of 50, with osteoarthritis and a BMI less than 35. Further, certain patients are at a much higher risk of adverse local tissue reaction and metal sensitivity. Female patients, patients receiving corticosteroids, patients with kidney problems, those with suppressed immune systems, patients who are overweight or those with high levels of physical activity and those with a suspected metal sensitivity should not be implanted with a metal-on-metal implant. It is likely that as time goes on and more information is gained regarding metal-on-metal hip implants, physicians will become even more vigilant about testing patients for metal poisoning and will choose candidates for all-metal devices even more carefully. A metallosis lawyer can give you a good idea of whether you are a candidate for a metal hip lawsuit.