Metal-on-metal hip implants have been a frequently used option for patients facing hip joint replacement. A metal-on-metal total hip implant is a medical device that consists of a cup, ball and stem, all of which are made of metal. This type of hip implant was marketed to younger patients since metal was supposed to last longer than other materials.
Currently, there are two available types of metal-on-metal hip options: (1) the total hip replacement implant and (2) the total resurfacing hip implant. The total hip replacement option is used more commonly in the United States, while the total resurfacing hip option is used mainly in other countries. Commonly used metal-on-metal hip implants used in the United States include:
- Stryker Rejuvenate & ABG II Hip Systems
- DePuy ASR XL Acetabular System
- DePuy Pinnacle Hip Solutions System
- Biomet M2a Magnum Hip Implant
- Zimmer Durom Cup
According to the U.S. Food and Drug Administration (FDA), as of December 31, 2010, the agency has cleared 175 metal-on-metal hip submissions for marketing, primarily through reliance on a provision of the agency’s 510(k) process. Most of these submissions were submitted as modifications to previously approved components. This process allows for clearance of components that are “substantially equivalent” in terms of safety and efficacy to those already on the market. This controversial approval system does not require pre-market studies.
Certain models of metal-on-metal hip implants have been found to present unique risks to the hip implant patient. These risks may include:
- Release of metal particles into the body and/or bloodstream: Contact between the metal ball and metal cup may cause metal particles to enter the body and/or bloodstream.
- Possible bone and/or tissue damage: Metal particles released into the body could potentially damage the bone and/or tissue that surround the hip joint and hip device. These tissue and/or bone reactions are known as an “adverse reaction to metal debris” (ARMD) or an “adverse local tissue reaction” (ALTR).
- High levels of metal ions in the bloodstream: Patients with elevated levels of metal ions in their bodies may experience heart, thyroid, and/or nervous system problems.
- Groin, hip or leg pain
- Swelling of the hip joint
- Walking with a limp or a change in the way one walks
Hip implant patients may require a revision surgery if the metal-on-metal hip device has failed. A hip revision is a medical procedure in which the failed hip implant is removed and replaced with another hip device. Revision may be necessary for patients who have experienced adverse metal reactions from a metal-on-metal hip implant.
Due to concerns regarding their safety and efficacy, metal-on-metal hip implants have come under increased scrutiny by the FDA in the past several years. On May 6, 2011, the FDA issued orders to manufacturers of metal-on-metal hip devices requiring them to undertake post-market surveillance studies of their respective products. In particular, these studies will address safety issues related to metal-on-metal hip devices. On March 29, 2012, the FDA announced its plan to convene a panel to assess the risks and benefits of metal-on-metal hip devices. The panel convened on June 27-28, 2012 in Gaithersburg, Maryland for hearings related to the safety of metal-on-metal hip implants. For summaries of the topics discussed during the hearing, click here.
International regulatory agencies have also expressed concerns regarding metal-on-metal hip devices. On April 22, 2010, the UK’s Medicines and Healthcare product Regulatory Agency (MHRA) released a medical device alert recommending follow-up blood tests and radiology exams for patients with painful metal-on-metal hip replacements. This alert advised that patients with metal-on-metal implants be monitored by their doctors for a minimum of five years after implantation. On February 28, 2012, the UK’s MHRA released an updated medical device alert now advising that patients with metal-on-metal hip implants be monitored by their doctors annually for the lifetime of their device.
Revision rates for metal-on-metal hip implants are high when compared to hip implants made from other material. According to a study released by the British Medical Journal, “Average failure rates at seven years are 11.8% for resurfacing and 13.6% for metal-on-metal hip replacement, although failure rates vary with the brand used. This compares with rates of 3.3% – 4.9% for hip implants made from other materials.” These results are based on data provided by the National Joint Registry for England and Wales.
If you or a loved one have undergone a total hip replacement, please contact our firm at 1-800-247-1623 or email@example.com for a free consultation to discuss your legal rights.