Chromium & Cobalt Blood Poisoning and the Metal Hip Implant:

Types of Potentially Risky Metal Hip Implants

Recipients of an all-metal hip implant or a metal-on-ceramic hip implant may wonder about their particular risk level for developing metallosis. While most hip implants and hip implant systems share some of the same issues, there are also important differences to be aware of. The issue with the true metal-on-metal hip implants generally occurs when the acetabular cup and ball rub against one another during times of physical activity, causing metal ions to shear away and enter the tissues or bloodstream. The metal implants which implemented a ceramic ball were thought to avoid this rubbing of metal on metal, however in some instances corrosion occurred at the metal neck juncture or at the site of the metal trundles which allow the various parts of the hip implant to snap together.

While the surface of the neck juncture and metal trundles in these ceramic-ball implants is considerably smaller than the surface of the all-metal ball and acetabular cup rubbing against one another, the systems with the ceramic ball nonetheless have serious risks of metallosis. Of the following hip implants, the DePuy ASR XL, the DePuy ASR Hip Resurfacing System, the Stryker Rejuvenate, the Stryker ABGII and the Smith and Nephew R3 Acetabular System have been recalled although sales have been suspended on the Zimmer DuromAcetabular Component and it is believed more recalls of other metal hip implants will follow. The list of potentially risky all-metal or partial-metal hip implants includes:

• Metal-on-Metal DePuy ASR XL Acetabular Hip System
• Metal-on-Metal DePuy ASR Hip Resurfacing System
• Metal-on-Metal DePuy Pinnacle Acetabular Cup System
• Ceramic-on-Metal Stryker Rejuvenate Hip Implant
• Ceramic-on-Metal ABGII Hip Implant
• Metal-on-Metal Biomet M2A Magnum Hip Implant
• Metal-on-Metal Smith & Nephew R3 Acetabular Hip System
• Metal-on-Metal Wright-Conserve Total Hip System
• Metal-on-Metal Wright-Conserve Profemur Total Hip System
• Metal-on-Metal Zimmer Durom Acetabular Hip Component

Risks of Metallosis in the Various Types of Metal-on-Metal Hip Implants

In the simplest terms, metallosis occurs when the body perceives a metal implant as foreign and reacts by trying to rid itself of the implant. When the body is unable to remove the implant, inflammation, pain and tissue necrosis can result. When metal from an implant rubs against another metal part, or corrodes when bodily fluids become trapped around the specific metal part, microscopic flecks of cobalt and chromium metals travel into surrounding tissues or even into the bloodstream.

The body attempts to protect itself from these metal particles by sending macrophages—special white blood cells—to attack the area and obliterate the metal particles. The body’s goal is to “trap” the metals in the inflamed area and prevent them from spreading to other parts of the body. In some instances with metal hip implants, the immune system will send these “fighter” cells to the synovial membrane which can result in a condition known as synovitis. While synovitis is similar to arthritis, or joint inflammation, synovitis will result in extreme levels of inflammation in the thin layer of cells lining our joints, in turn leading to pain and limited mobility.

Unfortunately, the body simply doesn’t possess the necessary level of defenses to fight against the release of cobalt and chromium. The longer these metals remain in the body, the more damage the body suffers. In some cases, the bone around the implant can even be destroyed as a result of these metals, leading to loosening of, and, eventually, total failure of the implant. When a fracture, severe infection, or implant loosening occurs, a revision surgery will likely be required in which the hip implant is replaced with a different type of implant.

Doctors do not fully understand why some individuals react more strongly to metals in the body, while other individuals appear to have a fairly high tolerance level for the presence of metals. Those who have metal sensitivity—which is essentially an allergic reaction to the metals—will not only have a “normal” autoimmune response to the metals, but their immune system will multiply its efforts to eliminate the foreign body. When this occurs, normal, healthy tissue can get “caught in the crossfire,” so to speak, becoming damaged in the process. Unfortunately, even those persons whose bodies kick into serious overdrive in an effort to eliminate the cobalt and chromium in their systems may likely be fighting a losing battle.

When the white blood cells attack a foreign body such as a metal implant, they remember the organisms they have tagged before when an invasion was attempted. Every time the body fights a foreign invader, it produces secretions whose goal is to wipe out the invader. A metal hip implant, however, is constantly releasing metal ions into the surrounding tissues and bloodstream, keeping the immune system in a frenzied state as its attempts to eliminate the foreign body is foiled, time and time again.

Think of a serious food allergy in which the body has identified a particular substance as so dangerous to its very existence that an exaggerated autoimmune reaction is triggered should the body come in contact with the food. In the case of a metal hip implant which is releasing harmful metals, the body may be unable to find any sort of parallel with harmful objects encountered in the past. Recipients of a metal hip implantsmay wonder what the actual risks of developing metallosis may be. One study detailed in the Journal of Orthopaedic Research followed 259 patients who received all metal hip replacement systems or hip implants and compared the group with a control group of age and gender-matched subjects. Compared with the control group all the patients tested much higher cobalt and chromium levels. In fact, cobalt levels averaged 50 times higher while chromium levels averaged 100 times higher in those with the metal hip implants than in the control group--every patient with a metal hip implant showed evidence of metal debris in the body, most at extreme levels.

Symptoms of Metallosis

Those who have a metal-on-metal hip implant or a metal-on-ceramic hip implant should be aware of the potential symptoms of metallosis. Pseudo tumors—a mass of inflamed cells which closely resemble a “traditional” tumor but are actually just a collection of fluid—as well as a noticeable rash (which can be indicative of necrotic or “dying” tissues) are possible symptoms of metallosis. Pain in the hip or groin area, difficulty in walking or standing, obvious swelling and inflammation, and loosening or failure of the metal hip implant are also key symptoms of metallosis.

Studies show that women who receive hip implants are at a greater risk for metallosis, as are those individuals who are smaller in stature, as well as obese patients. In these cases, more stress is placed on the implant, resulting in higher levels of metal ions being released into the body. As the cobalt and chromium levels continue to build up in the body, emotional disturbances, headaches, dizziness, confusion, memory loss, gastrointestinal disorders, recurring infections, burning, tingling or numbness of the extremities, skin rashes, cardiovascular, renal and thyroid problems, and hearing and vision disturbances may manifest.

Consult an Attorney

If you are the recipient of any of the aforementioned  hip implants—whether you have yet experienced symptoms of metallosis or not—it is extremely important that you discuss the potential risks of your implant with your physician. Additionally, even if you have not yet experienced pain or any other specific signs of metallosis, you should also discuss your case with a highly qualified attorney who can evaluate the specific facts surrounding your implant. Your questions can be more fully answered and you can receive a better understanding of your rights.