In the United States, over 285,000 hips are replaced annually, and direct costs are estimated to exceed $35 billion annually (hip and knee replacements combined). As the population ages, this value of total joint replacement is expected to swell to over 4 million people requiring hip replacements annually.
Hip replacements are often necessary as the pain that a patient feels may limit their daily activities, and is indicated when there is limited range of movement of the hip (ie. leg cannot be lifted or moved), or in cases where pain relief cannot be alleviated by physical therapy, anti-inflammatory drugs or other alternative medicines or treatment. Though the surgery has a high rate of success, there has been growing concern over the failure rates of some devices.
Most recently, warnings have come out of the United Kingdom over reports of high failure rates associated with the combination DePuy MITCH and Stryker Accolademetal-on-metal hip replacement components. The UK’s Medicines and Healthcare Products Regulatory Agency (MHRA) issued an alert on April 02, 2012 stating that the rate of revision surgery is increased in patients who received a DePuy MITCH acetabular cup/modular head in combination with uncemented Stryker Accolade femoral stems.
Failure Rate of DePuy MITCH and Stryker Accolade Metal-On-Metal Hip Implants
Information from the England and Wales National Joint Registry (NJR) has shown that the DePuy MITCH and Stryker Accolade metal-on-metal hip replacement components have a high revision rate of 10.7% after 4 years of implantation. The analysis also found a cumulative revision rate of 8.8% for MITCH TRH hip resurfacing systems. These failure rates are higher than what the U.K.’s National Institute for Health and Clinical Excellence (NICE) considers acceptable. This warning comes on the heels of a string of warnings regarding metal-on-metal hip implants, many of which have been the basis of industry-wide recalls.
The MHRA has advised surgeons not to use the DePuy MITCH and Stryker Accolade metal-on-metal hip replacement components together. Physicians are also advised by the MHRA to follow up with all patients who have received this combination of components as part of a metal-on-metal hip implant. Patients who received the DePuy MITCH and Stryker Accolade implant combination are also recommended to be tested annually for signs of high blood metal ions from the hip implant, which could be indicative of metallosis. Patients who have levels of blood metal ions (ie. chromium and cobalt) greater than seven parts per billion should have another blood test performed three months later to determine if the levels are increasing which could result in potential soft tissue damage. In patients demonstrating increased levels of these blood metal ions, it is recommended that an ultrasound or magnetic resonance imaging (MRI) be performed to assess any potential soft tissue damage.
This is not the first time that DePuy has had issues concerning metal on metal components. In August 2010, a ASR XL Acetabular metal-on-metal hip system was recalled due to approximately one out of every eight (13%) of the hip implants failing within five years of surgery resulting in a number of lawsuits. Similar lawsuits have also been filed over issues with other metal-on-metal hip systems, including another DePuy system, the DePuy Pinnacle.
The string of concerns surrounding metal on metal hip implants and their components are resulting in various FDA warnings. On March 29, 2012, the FDA announced that the Orthopaedic and Rehabilitation Devices Panel will meet June 27-28, 2012 to discuss the risks and benefits of metal-on-metal hip systems, as well as patient and practitioner recommendations for their use.
The expert panel will discuss failure rates and modes, metal ion testing, imaging methods, local and systemic complications, potential risk factors, and considerations for follow-up after surgery.
On May 6 2011, the FDA requested that manufacturers obtain more information about how much metal hip replacements shed, to determine the level at which the metal particles become dangerous, and to determine the potential side effects of metallosis.
The 501(k) Process
Metal-on-metal hip systems gained market approval in the US prior to 1976 legislation that gave the agency premarket authority over medical devices. They were designated as Class III (higher risk) devices but are regulated under the 510(k) premarket notification program. The 501(k) process was intended to streamline and to allow devices to get to the market faster, without the necessity of rigorous safety and efficacy testing as manufacturers could claim the product was similar to others on the market. The Institute of Medicine (IOM) reports that approximately 90% of medical devices go through the 501(k) process. Concerns have been expressed regarding the 501(k) regulatory approval process due to rates and the serious nature of some medical device recalls which have been granted market approval through the 501(k) approval process.
The agency is currently reviewing all safety and effectiveness data related to these “preamendment devices,” including metal-on-metal hip systems, in an effort to determine their proper risk classification and how these devices should be regulated in the future. A decision on the proper classification of metal-on-metal hip systems is forthcoming.
If you are having problems with your metal hip replacement, and think it could be related to your device, call us at 800-553-8082 and we will try to give you your options and steer you in the right direction. You can also discuss with our lawyers your potential hip replacement lawsuit on line.