Metal on Metal Hip Replacements
Thousands of patients with hip replacements received bad news in March 2011 when the Food and Drug Administration Medical Product Safety Network (MedSun) newsletter announced that metal on metal (MoM) implants could produce high levels of metallic debris resulting in soft tissue damage, infection, dislocation, or device failure. According to the FDA, some studies indicate that excess heavy metal ions may also cause neurologic and cardiac disorders.
For quite some time, joint replacement surgery has offered patients with painful hips, knees and other major joints significant pain relief and increased mobility. The surgeries are so popular that implant device manufacturers have engaged in research, development and marketing wars to gain valuable market share. These manufacturers have been killing themselves to build a better mousetrap and grab a larger share of this lucrative market. Our Florida hip implant attorneys are knowledgeable and experienced in these types of joint replacement cases.
By 2000, hip replacement surgery had become more and more common as Baby Boomers aged and medical technology advanced. Physicians often recommend hip replacement implants for osteoarthritis patients who suffer from pain, stiffness or difficulty walking that does not respond to conservative treatment. An estimated 250,000 Americans undergo hip replacement surgery each year, and about a third of them receive metal-on-metal hips made from metals like cobalt and chromium.
A hip joint normally operates with a ball-shaped head at the top of the femur (the thigh bone) that fits into a cup-shaped cavity called the acetabulum (the socket) at the base of the hip bone. This ball-and-socket arrangement gives the hip its ability to rotate.
- During total hip replacement surgery, damaged portions of the patient’s hip joint are removed and replaced by artificial devices. The ball at the top of the femur is replaced with a prosthetic ball of metal or ceramic; the socket (acetabulum) is removed and replaced with an artificial cup made of metal, ceramic, or plastic, plus a stem to support the femoral head.
- In total hip resurfacing surgery, the head of the femur is trimmed and covered with a metal cap instead of being replaced. Damaged bone and cartilage in the acetabulum is then removed and a metal shell is inserted.
Some implants are popular Metal on Metal (MoM) devices, where both the ball and socket are made of metal. Your hip implant attorneys at the Florida law firm of Searcy Denney explain that once implanted, these two components may rub together – sometimes with disastrous results. There is increasing evidence that if the metal parts don’t fit together precisely, they can produce tiny metal shavings that can then enter the patient’s system.
This metal debris can cause inflammatory reactions, tissue damage, and bone loss around the area of the ball and socket connection. The Food and Drug Administration (FDA) website contains reports that suggest systemic effects like cardiomyopathy (deterioration of the function of the heart muscle), thyroid dysfunction, and neurological changes including sensory, auditory, and visual impairment which may result from metal debris around the joint.
If the metal debris travels throughout the body, it can cause metallosis, a buildup of metal which kills surrounding tissue (necrosis). Symptoms of metallosis include pain around the joint, difficulty walking, swelling at the implant site, and rash. Metallosis can lead to osteolysis, in which a bone degenerates, causing an implanted device to become loose. If a device loosens, it must be removed and replaced through a second surgery known as a “revision.”
On May 6, 2011, the FDA issued a letter to 21 metal-on-metal implant manufacturers mandating that they study the issue of potential heavy metal poisoning in patients with the devices. Each manufacturer was to design and submit detailed testing protocols, for post-market surveillance of adverse events related to the safety of their products.
Under the agency’s rule, information from implant patients with complications from metallic debris will have to include blood samples so levels of metallic ions may be determined. This massive testing program will be the first clinical trial of the MoM hip replacement implants.
MoM devices were approved originally by the FDA under the fast-track approval process called 510k, by which a medical device can be approved for market without establishing its safety and efficacy. All the manufacturer needs to show is that the device is substantially equivalent to a device already in the market. Under the 510k process, serious side effects, complications, and other dangers are often not discovered until after the product is already in the market.
Government Regulation & Study
In the last few years independent researchers, the FDA, and its British counterpart, the United Kingdom’s Medicines and Healthcare Products Regulatory Agency (MHRA) have become aware of serious consequences of MoM joint replacements:
- At the September 2009 Annual Congress of the British Orthopaedic Association, David J. Langton and colleagues in the Joint Replacement Unit at the University Hospital of North Tees in Stockton, England, released results of a review made between 2002 and 2009 of 155 Birmingham Hip resurfacings (BHR), 420 articular surface replacements (ASRs), and 75 total hip replacements using DePuy’s ASR XL implants, all of which are metal-on-metal models. Langton reported 22 failures in patients with ASR implants (4.5%). Those patients experienced groin pain and varying degrees of tissue necrosis. Their medium blood chromium levels were as much as seven times higher than those of asymptomatic patients, and their median cobalt levels were more than 25 times higher than those of asymptomatic patients. Langton’s study also suggested a correlation between joint size and orientation with metallic debris, tissue necrosis, higher chromium and cobalt levels, and other signs of failure. Results indicated that the larger the size of the cup (socket) and the greater the anteversion (forward rotation), the greater the failure rate.
- At the 2010 annual meeting of the American Academy of Orthopaedic Surgeons, Langton reported similar results, suggesting that only size and cup inclination have an effect on metal ion levels that can cause serious damage and require revision of metal-on-metal hip replacement surgeries.
- On April 22, 2010, the MHRA issued a medical device alert based on adverse event reports of MoM hip replacement revisions. The alert cites reports of patients with metal-on-metal hips who developed soft tissue necrosis because of metallic debris.This medical device alert was issued to the medical community which was asked to follow patients at least annually for the five years after joint replacement with a MoM device – but more frequently if symptoms emerge. If symptoms emerge, blood tests to measure metal levels are advised, as well as cross-sectional imaging including MRI or ultrasound scan.
- Data from the MHRA database resulted in a voluntary recall on August 24, 2010 of the DePuy ASR total hip system because its five year revision rates were about 13%.
- In a surveillance order in May 2011 issued to Metal on Metal hip replacement manufacturers, the FDA referenced data from the Australian Orthopaedic Association Joint Replacement Registry of early revision rates implicating MoM joint replacement devices also marketed in the US. The products included:
- DePuy ASR: 7.8 revisions at 5 years (recalled in Australia in 2009, in the US in 2010);
- Smith & Nephew Birmingham Hip: 4.9 at 5 years with BHR head, 2.4 at 5 years with R3 head;
- Corin Medical Cormet resurfacing: 7.1 at 5 years;
- Biomet: 4.0 at 3 years for total hip with M2a liner, 2.2 at 3 years with Recap (resurfacing);
- Zimmer Durom total hip: 4.6 at 5 years (recalled in US).
Risks & Complications of Metal-on-Metal Medical Devices
The FDA’s website on metal-on-metal medical devices confirms:
“All artificial hip replacement systems have risks related to implant or material wear. Metal-on-metal hip (MoM) replacement systems have unique risks in addition to the general risks of all hip implant systems.”
General risks of hip implant systems include:
- Hip dislocation
- Bone fracture
- Joint inflammation
- Local nerve damage causing numbness or weakness
- Device loosening or breaking
- Different leg lengths
- Bone loss (osteolysis)
When you add to these the danger of complications that could arise from metallic debris, it is clear that patients who have implanted metal-on-metal hip replacements indeed face unique and serious risks. That is why lawsuits are beginning to be filed on behalf of patients who have suffered severe pain, debilitating infections, and other injuries from MoM hips.
Florida Hip Implant Attorneys Warn
Anyone who has a metal-on-metal hip replacement should be on the alert for post-surgery symptoms that could indicate an adverse reaction to metal particles from the implanted device. Patients with any of the following symptoms should consult their orthopedic surgeon, who may recommend blood tests, joint aspiration (removing fluid from around the joint), or special imaging tests:
- Pain in the groin, hip or leg
- Swelling at or near the hip joint
- A limp or difficulty walking
- Chest pain
- Shortness of breath
- Numbness or weakness
- Changes in vision or hearing
- Feeling cold
- Weight gain
- Change in urination habits
The FDA advises physicians following up with MoM hip replacement patients to recognize that localized lesions connected to metal debris reactions can include:
- Local nerve palsy
- Palpable mass
- Local swelling
- Joint dislocation or subluxation (partial dislocation)
When counseling patients who are considering total hip replacement implants, the FDA warns orthopedic surgeons NOT to implant metal-on-metal hip systems in:
- Patients with moderate to severe renal insufficiency
- Patients with known sensitivity to metals such as cobalt, chromium, or nickel
- Patients with suppressed immune systems
- Patients currently receiving high doses of corticosteroids
- Women of childbearing age
Advice from Your Florida Hip Implant Attorneys
If you are considering a hip replacement device, ask what kind of implant the surgeon intends to use, and what the alternatives are. Don’t assume that a joint replacement device is safe because it has been approved by the FDA and is on the market.
Do your own research before undergoing any medical procedure. The Internet can be a powerful tool, as long as you verify the credibility of information sources. Your health and safety depend upon challenging false assumptions and making informed decisions.
If you already have a metal on metal hip implant, and need to discuss your legal options, contact a hip implant attorney at Searcy Denney. Our lawyers have over three decades of experience filing mass tort lawsuits.
Watch one of our clients tell her real life story of the suffering she has been forced to endure as a result of injuries she suffered from defects in Stryker’s Rejuvenate Hip Implant.