Cobalt Chromium Toxicity

metal prostheses

DePuy Hip Recall Tweets about Pinnacle Hip Help Website


Hip Surgery: The Importance of Doctor-Patient Communication


An open and honest dialogue with your doctor before surgery contributes to better outcomes. This means providing your physician with a comprehensive medical, surgical, and social history. This also ensures the doctor gives you the best care in creating a plan that fits your specific needs. Before any surgery, it is essential to voice any questions or concerns you might have.

The American Academy of Orthopedic Surgeons (AAOS) created a list of questions which may help in discussions with your doctor:

  • What are your experiences with specific hip implant devices and how often do you use one over the other?
  • What are the risks and benefits of different devices (metal-on-metal, metal-on-polyethylene, ceramic-on-polyethylene, and ceramic-on-ceramic devices)?
  • If applicable, what is the surgeon’s personal experience and outcomes with the respective devices?
  • If your surgeon recommends a certain device, ask why that hip implant is the best for your situation.
  • What are the major and/or most frequent complications of surgery?
  • Is the skill and experience of the orthopaedic surgeon more important than the device or procedure?
  • Can you give me any information on outcomes and complication rates?
  • If I do not have surgery, what is the risk?
  • How much pain can I expect, and how will it be managed in the hospital and after I go home?
  • How long will the device last, and what can I do to make it last as long as possible?
  • What are the pros and cons of minimally invasive (mini-incision) surgery? Does it really make a meaningful difference in the result, or does it pose unnecessary risks?
  • What will I be able to do/not do after my total joint replacement?
  • Is therapy necessary after surgery?
  • How long will I be in the hospital?
  • Will I be able to contact you after the surgery if I have a question or problem?

October 2014 Stryker Litigation Update



Hi. This is Stuart Talley. Bill Kershaw and I are the attorneys responsible for the Stryker Rejuvenate and ABG II hip cases. We are providing an update on the litigation status currently pending in Minneapolis, Minnesota before Judge Donovan Frank.  Right now, there are about 4,000 cases filed and that number goes up every day. We receive phone calls from new people every day who are having problems with their Stryker hips. By the next update, there will probably be around 6,000 cases on file.

We have not had a status conference with the court for a couple of months. The next one is set for November 6, 2014. In the interim, there was a lot of paper work filed with the court on discovery issues. Discovery is the process where we get documents from the defendants; we take depositions of the defendants, their engineers, executives, salesmen. The idea is developing evidence we will need for trial.

One of the big battles brewing in this case involves documents. In this case, Stryker informed us they produced all their documents. To date, we received about 700,000 pages. It seems like a lot but in the context of cases like this, it’s really a drop in the bucket. In other hip cases we’ve handled, defendants typically produced anywhere from 20 to 60 million pages of documents.  We’ve looked at Stryker’s documents and discovered enormous gaps in email production. Email production is where you see most of the documents. There are generally millions of emails between engineers, between sales reps, where we find the best evidence for the case. We discovered certain key witnesses produced one email or none at all. From our standpoint, it appears documents were destroyed or simply not produced.

We are trying to get a deposition from a Stryker representative to find out what happened to all the documents. We also want to know if they were destroyed. And if so, is there a way to get them back. Sometimes, emails or deleted documents off a server can be retrieved from backup tapes. Companies often have servers with large amounts of data backed up on tapes. Those tapes are then stored in a separate, safe location apart from the facility with the servers. This ensures that if there is a disaster they can use the tapes to restore data. We hope there are the backup tapes on emails we can use to fill in the gaps.

Stryker does not want us to take that deposition, and filed a motion to quash the deposition. They asked the judge to prevent us asking questions regarding the documents and where they went. This issue will be decided on November 6. If it’s determined Stryker destroyed documents, and they destroyed documents knowing of an impending lawsuit (after the recall), it poses serious consequences for Stryker. If you can show the knowing destruction of evidence, judges have lots of remedies available to punish the party that destroyed the evidence. Judges can impose monetary sanctions, issue sanctions, or jury instruction sanctions. An issue sanction is when the judge has an issue deemed admitted by Stryker. For example, say there are key documents showing Stryker knew about the problems with the hip before it was put on the market. If we can’t prove this as a result of documents that were destroyed, the judge might enter an issue sanctioned so jurors are told at the trial Stryker knew there were problems with the hip before they put it on the market. With a jury instruction sanction, you can have the judge advise the jury that Stryker destroyed evidence in the case, and for purposes of deciding the case, they can assume there were documents that probably would have hurt Stryker down the road.

Correlation between Smoking and Risk of Revision Among Patients with Hip Replacements


Significant Correlation between Smoking and Risk of Revision Among Patients with Metal on metal (MOM) hip replacements

World wide, an estimated one million people are implanted with metal on metal (MOM) hip prostheses. It was originally believed that the MOM prosthesis would have a decrease in implant wear over time. However, recent studies and case reports demonstrate the contrary. MOM total hip arthroplasties indicate a higher failure rate in comparison to other types of hip prostheses. Some prominent effects that result in an elevated failure of the MOM bearings include aseptic loosening (loosening of the total joint replacement) and a hypersensitivity to the metals.

Metal hypersensitivity can cause a myriad of health issues such as osteolysis, severe and chronic pain, infection, and periarticular tissue reactions, which is aptly named an adverse local tissue reaction (ALTR). These all subsequently contribute to the high rate of failure of the MOM prostheses. In addition to the ALTR, there are reported cases of massive bone and tissue necrosis (death) along with the formation of periprosthetic pseudo-tumors. In terms of hip implant revisions, those patients suffering from pseudo-tumors had worse revision rates than those that did not.

Metal hypersensitivity, or metal sensitization and allergy, stems from the release of cobalt and chromium found within the metal bearings. In this study, it is also found that smoking patients with MOM hip prostheses led to poorer results of the hip prostheses than non-smokers. This is due to the association between the traces of cobalt and other metal elements found in cigarette smoke, and the elevated metal ions from the prosthesis. These two sources of metal are potential triggers for an increase in metal hypersensitivity and contribution to a higher risk for revision.

In this study, patients were separated into two groups: never-smokers and ever-smokers. The ever-smokers were further subdivided into current smokers and former smokers. The main concern with the study focused on an all-cause revision, known as any change or removal of a single or multiple prosthetic components. The causes of revision were divided into the following categories: aseptic loosening, infection, dislocation, periprosthetic fracture, impingement, or implant migration. During the revision, findings for ALTR were also recorded. These findings included metallosis, presence of pseudo-tumors, and tissue necrosis (death). In addition to the aforementioned subdivisions, the study was further divided into two sub-cohorts among patients with MOM, cobalt-chromium alloy hip prostheses versus patients with non-metal, ceramic-on-polyethylene (COP) hip prostheses.

The results of the study indicated that ever-smokers in both the MOM and COP cohorts suffered from secondary arthritis as a result of surgery. Among ever-smokers and never-smokers with MOM prostheses, the revision rate was more than tripled for the ever-smokers (8.7 revisions per 1,000 persons) compared to the never-smokers (1.5 revisions per 1,000 persons). The reason for such a discernible difference between never-smokers and ever-smokers with MOM prostheses was an increase in an adverse local tissue reaction (ALTR) among the ever-smokers. In conclusion, there is a strong correlation between smoking and an increase failure rate of MOM hip replacements. This association was not definitively evident among never-smokers and ever-smokers with COP hip arthroplasties.

Source: Strong Association between Smoking and the Risk of Revision in a Cohort Study of Patients with Metal-on-Metal Total Hip Arthroplasty http://onlinelibrary.wiley.com/doi/10.1002/jor.22603/pdf

 

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

 

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