Cobalt Chromium Toxicity

Metal on Metal Hip Recall Lawyer

Metal Implants and Hypersensitivity


Metal Hypersensitivity

Metal hypersensitivity is an immune mediated response resulting from exposure to certain metals such as cobalt and chromium. An immune mediated response occurs when there is a trigger, like a foreign agent, that causes an immune reaction. These triggers can range from seasonal allergies to specific cells responding to an exposure of metals. It is important to differentiate between the immune reaction from an allergen, like pollen, and a metalloid material. Whereas a seasonal allergy generates immediate symptoms, like itching, watery eyes, and sneezing, a metal allergy induces a delayed response to the exposure of these elements.

Once your immune system is exposed to new metals, your body creates an immunological memory. This occurs because certain cells called T-lymphocytes recognize the metals as a foreign body and want to create a memory in order to activate immune responses. This is the body’s defense mechanism if the metals continue to be present, or are reintroduced, in the body. After formation of immunological memory, if you are exposed to the metal again, the body will activate an inflammatory reaction in order to better defend against this foreign object. This gives the delayed response of metal hypersensitivity. The symptoms of delayed hypersensitivity are analogous to the reaction you would get from a food allergy or insect sting.

 

Symptoms of Metal Hypersensitivity

Contact dermatitis, most commonly known as a skin rash, is the most suitable way to describe the main symptom of metal hypersensitivity. Other symptoms include but are not limited to: blisters, vesicles, erythema (redness), pruritis (itching), and inflammation around the area of exposure. Due to its delayed nature, symptoms may not appear until a day after contact with the metal and may take many days to return back to normal.

Metal implant devices, such as Metal on metal (MOM) hip prostheses, lead to a more complicated metal hypersensitivity. It is difficult to describe the effects of a MOM implant because the field of visualization is restricted since the device is implanted within the body. However, studies demonstrated an immune response and hypersensitivity in the tissue areas interacting with the debris from implanted devices. Wear debris is the result of movement, friction, metal corrosion (metal oxidation), and metal ions released from the device. This can cause severe pain, swelling, limited range of motion, joint effusion (abnormal buildup of fluid between layers of tissue in or around joints), inflammation, and osteolysis (bone loss).

What happens to my device if I have a metal hypersensitivity?

Wear debris is a by product of corrosion of the implant material. Metal ions and particles are released into the surrounding tissue over time. People with a hypersensitivity to the metals of their implant will react differently compared to those who don’t have an allergy due to the triggering of an adverse response. As previously mentioned, an inflammatory response is triggered when the immune cells are exposed to the metals like cobalt and chromium. The response ranges from mild to severe depending on the extent of the sensitivity, levels of metals within the body, and wear debris. Persistent inflammation, due to the MOM implant, can cause muscle spasms, myofascial pain, headaches, tinnitus (ringing in the ear), vertigo (dizziness), and angioedema (swelling under the skin). A chronic inflammatory reaction from continued exposure, from a MOM device, can lead to loss of bone strength, implant loosening or fracturing, and osteolysis (bone loss).

Testing for Metal Hypersensitivity

It is difficult to test because the environment on the skin is different than the periprosthetic area deep within the tissues. There is a blood test called lymphocyte transformation test (LTT) which determines if a patient suffers from metal hypersensitivity. The LTT measures the proliferation of T lymphocytes which are the immune specific cells that form the immunological memory in response to metal exposure. The blood is collected and put within special tubes in order to decrease the risk of contamination. Similarly, it is tested within a laboratory that follows strict procedural protocols and standards to avoid contaminating the sample.

 Metal Hypersensitivity and Implant Performance

Approximately 25% of people with properly functioning MOM devices have a metal hypersensitivity and more than 60% of people with malfunctioning MOM devices have a metal hypersensitivity. This is a stark and alarming contrast which is attributed to the poor implantation. There is also a greater failure rate as a result of metallosis, hypersensitivity, and adverse local tissue reactions (ALTR). Hypersensitivity is strongly correlated with poor implant performance and generally makes revision difficult and risky as a result of the body’s reaction.

Source: Metal Hypersensitivity to Implant Materials By: Marco Caicedo, Ph.D

http://www.tmj.org/site/pdf/Metal_Hypersensitivity.pdf

Metal on Metal Hip Prostheses and Total Hip Arthroplasty Effects on Auditory and Visual Health


In the United States, there are over half a million patients implanted with metal on metal (MOM) hip prostheses. The typical elements released by the metal on metal hip prostheses are cobalt and chromium. The normal levels of cobalt and chromium within the body are below a microgram per liter of blood, or below a part per billion. The term microgram per liter is analogous to parts per billion. There are studies demonstrating that a normal range is within 0.1 to 0.3 micrograms per liter. According to this study, patients with well functioning MOM hips, had cobalt-chromium blood levels between 1.5 and 2.3 micrograms per liter. This is ten times higher than normal physiological levels and significantly contributes to the potential for cobalt-chromium toxicity, or metallosis. In association with metallosis, the study indicates that failure with prostheses was connected to visual and auditory issues resulting from elevated cobalt-chromium levels. There is a strong correlation between device failure with visual and auditory dysfunction.

In addition to the aforementioned findings, the study determines whether or not chronic low levels of metal exposure result in obvious physiological effects on the auditory and visual systems as well. In order to determine the effects of chronic low levels of cobalt-chromium, participants met with both an otolaryngologist and an ophthalmologist in order to determine primary or pre-existing pathologies within the ears and eyes, respectively. Subjects then underwent objective and subjective audiometric testing in order to assess auditory health and function. Similarly, the subjects demonstrated their visual health and functioning via subjective and objective visual testing. There were two types of participants in this study: those with MOMHR and those with total hip arthroplasty (THA). The participants in this study were then separated into groups based on their age and time since surgery. The participant’s blood tests also revealed that those with MOMHR had a blood, plasma, urinary cobalt and chromium levels that were 5 to 10 times higher than the THA participants. In terms of objective audiometric and visual findings between the MOMHR and THA groups, there was no observable difference, and patients in each group had similar auditory and visual function.

There is no conceivable evidence between MOMHR and altered brain stem responses for patients with exposure to chronic low metal levels. However, there is optic nerve atrophy (damage) in patients with exposure to high metal levels in their system  which reflects visual loss among this specific population. Whereas patients with long term exposure to low metal levels had no obvious association with auditory or visual defects, the patients with malfunctioning hip prostheses and elevated metal levels (up to hundreds in micrograms per liter) suggested visual and auditory defects.

Source: Auditory and Visual Health after Ten Years of Exposure to Metal-on-Metal Hip Prostheses: A Cross-Sectional Study Follow Up http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0090838

 

Influence of Femoral Stems with Modular Neck Designs on Health Consequences and Presence of Metal Ions


Metal on metal (MOM) prostheses have different designs. One such MOM stem design, Profemur Z, includes a femoral stem with a modular neck that enables adjustments which are separate from femoral fixation. There is concern with the potential for fracture of the modular neck in relation to the modular junction. Fracturing of this junction may potentially lead to the production and release of metal debris and ions causing adverse local tissue reactions, or ALTR.

The Profemur Z allows for a modular neck-body junction which can be inserted with a variety of orientations, angles, and directions. The neck has a taper where a modular head may attach. These models only used titanium alloy necks until cobalt chromium alloy necks were available. There are many cases of corrosion and modular neck fracture secondary to failure of the Profemur Z stem design. According to the Australian Orthopedic Association’s National Joint Replacement Registry, there is an 11% failure rate for patients with this device over a 5 year period. This is a significant failure rate compared to other femoral stems.

An increase in serum chromium and cobalt levels was indicated in patients with MOM hip prostheses. The modular head-neck junction, and bearing surface, is the main cause of the cobalt and chromium release in the blood stream. There was a significant elevation in cobalt and chromium serum levels as a result. Whereas titanium alloy prostheses, had low elevations of cobalt and chromium serums, the adverse local tissue reaction, results from the release of cobalt and chromium in those stem designs produced with a modular neck made from a cobalt-chromium alloy. The etiology of modular neck fractures stems from fatigue failure and crack formation from corrosion due to metalurgical reactions of the device with body chemistry. In addition, those stem designs with a modular neck-body junction made of both chromium-cobalt and titanium have the ability to cause even more detrimental local tissue reactions.

Crack formations on the neck-body interface are the result of oxide-formation and oxide-driven stress. Over time, pitting and formation of cracks are exacerbated by increased stress corrosion and oxidation surrounding the interface of the mechanism. Stress corrosion causes the dissolution process of metal ions. The consequences of elevated metal ion levels from the cobalt-chromium stems in patients include pseudotumor formation, severe pain, osteolysis, and taper corrosion.

Subsequently, there is an increased revision rate for prostheses with this femoral stem design. During revision surgeries, findings illustrated significant corrosion at the modular neck-body interface.

The Full Article can be read at:

http://www.arthroplastyjournal.org/article/S0883-5403(14)00297-6/abstract

Source: Silverton Craig D., Jacobs Joshua J., Devitt Jeffrey W.,
Cooper H. John, Midterm Results of a Femoral Stem with a Modular Neck Design:
Clinical Outcomes and Metal Ion Analysis, Journal of Arthroplasty (2014), doi:
10.1016/j.arth.2014.04.039

Stryker Hip Recall What kinds of damages would I be entitled to?


Stryker Hip Recall Attorney – Legal Blog: What kinds of damages would I be entitled to?

Hi, this is Stuart Talley of Kershaw, Cook & Talley. Bill Kershaw and I are the partners responsible for the Stryker Rejuvenate litigation at the firm. I received a call yesterday from a client in Tucson, Arizona. She asked, “What kind of damages would I be suing for if I filed a lawsuit in a case like this?” Many clients were contacted by a company called Broadspire who promised to cover some of the out-of-pocket expenses that people incur as a result of the Rejuvenate recall.

Clients have questions and concerns about what kinds of damages they can recover in a lawsuit, and why they even need to file a lawsuit. Well, in order to recover your damages, you have to file a lawsuit. Broadspire only covers your out-of-pocket expenses. It doesn’t cover pain and suffering associated with an unnecessary hip operation or long-term lost earnings. It won’t reimburse your insurance company for amounts they spend to treat you in the future. The most important thing to understand is that when you have a recalled hip, early replacement is recommended. There are many studies indicating you’re going to have more problems with your hip in the future. You’re going to have more pain, dislocations, and additional surgeries; which would have been avoided if your hip worked properly in the first place. This is the biggest part of our case and why our clients want to sue.

If you have a Stryker Rejuvenate, call me directly at (916) 520-6639. My name is Stuart Talley and I am more than happy to talk about your situation and help protect your rights.  Please visit us at www.defectivehipsettlementcenter.com or our main site www.kershawtalley.com

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