What Patients Must Know About the Titanium Hip Replacement Recall: When Stryker Rejuvenate Patients Suffer Effects from Titanium

The Stryker Rejuvenate and ABGII were both recalled this past July after it was found the implants had a higher-than-normal risk of causing fretting, corrosion and the potential for metal ion debris to enter the body. Up until now, the focus regarding those metal ions has been on the cobalt and chromium shards which can lead to a variety of serious health issues including metal toxicity. The neck of the Rejuvenate and ABGII is constructed of the harder cobalt and chromium while the stem is constructed of titanium.

Titanium has generally been considered a “safe” metal therefore little attention has been given to the possible side effects of titanium. Titanium, over time, binds completely to bone and living tissue, minimizing the need for adhesives. The titanium component of the hip replacement device is also more flexible and lightweight than the cobalt and chromium component. Despite these “pluses” there may be risks inherent in a titanium hip implant component which few recipients are aware of.

Titanium Allergies Could Cause Problems in Rejuvenate Recipients

Metal allergies have been researched as they relate to metal hip implants because some thirty percent of the population have a metal sensitivity to nickel, and the cobalt and chromium implant contains at least 1% nickel. Titanium allergies, on the other hand, are a barely recognized problem. It is a fairly recent occurrence that a test known as MELISA® can test for titanium sensitivity although the test cannot measure serum levels of titanium in the bloodstream as tests for cobalt and chromium can do. Labs using the MELISA® test report that 4% of all patients tested for titanium sensitivity test positive.

Titanium Allergies Cause a Variety of Health Problems

Titanium sensitivity can be very frustrating for those who have the allergy as their symptoms can be somewhat vague and may be wrongly attributed to other health issues. Skin rashes in the hip implant area, muscle pain and fatigue, Chronic Fatigue Syndrome and chronic thigh pain may all indicate an allergy to titanium. Titanium is not only used in metal hip implants such as the Stryker Rejuvenate and ABGII, it can be found in many everyday articles including certain food coatings, cosmetics, sunscreen, medicine coatings, paint, certain whitening toothpastes, jewelry, vitamin supplements and even the hard candy coating found on Skittles and M & M’s.

Stryker Rejuvenate Patients May Be Subject to Titanium Corrosion

Like most all metals, corrosion causes a release of metal ions which bind with body proteins. A person with an allergy to titanium may find their body will attempt to attack the foreign particles of titanium when sensitivities to the metal are present. This attack will cause inflammation in the hip area and likely pain to the victim. The MELISA® test is currently the only test which has been proven to diagnose titanium sensitivities. Additionally, several studies have concluded that titanium metals frequently contain small amounts of nickel as a result of the processing. Therefore a person who is sensitive to both titanium and nickel could have extremely strong reactions to a Stryker Rejuvenate or ABGII hip implant.

Studies on Titanium Allergies

A study done in 2006 tested fifty-six recipients of a titanium-based hip implant device after each patient experienced a variety of adverse health issues following the implantation. Testing was done on each patient to determine whether they had sensitivities to any of the ten metals including titanium. Of the 56, 21 tested positive for a titanium allergy, 16 patients tested “ambiguous,” and the remainder tested negative for a titanium allergy. Of the 56, all but two underwent revision surgery to replace their titanium-based hip implant with a different implant material and all 54 showed “remarkable” improvement of their adverse symptoms. The conclusion of the article was that titanium, in those who are sensitive to the metal, can cause “clinically relevant hypersensitivity in a subgroup of patients exposed to titanium implants.” 

A 2004 study detailed in the Journal of Bone and Joint Surgery followed nine patients with titanium-based hip replacements who all suffered from severe thigh pain which worsened at night despite a well-fixed implant and no sign of infection. Eight of the nine underwent revision surgery after x-rays showed deterioration of the femur at the tip of the titanium stem. Following revision, the tip of the removed titanium stem was found to be highly acidic with considerable evidence of corrosion. As to whether the cobalt and chromium ions react negatively with the titanium ions, this same article did note that galavanic corrosion is more likely to occur in a hip implant using dissimilar metals.

Two specific case studies done in England determined titanium allergies were the culprit for the adverse health issues and one of the patients also suffered from a nickel allergy as well. Fatigue, exhaustion, fevers, headaches, suppressed appetite, pain, swelling, neurological disturbances and even confusion were noted by the two patients, yet once their titanium-based implant was removed, the symptoms disappeared completely.

Patients with Suspected Titanium Allergies and a Rejuvenate Implant

Those who have suffered pain, fatigue, and other adverse symptoms following their Rejuvenate hip implant should request that a MELISA test be performed to determine whether they have an allergy to titanium. While science has not yet determined whether the cobalt and chromium ions can react negatively to the titanium ions, it is definitely a possibility. Despite the titanium hip replacement recall of the Rejuvenate and ABGII in July, 2012, many of those implanted with the devices continue to experience serious health issues.   

What Patients Should Know Regarding the Stryker Rejuvenate Hip Recall: Theories of Design Defects Which Led to the Stryker Hip Recall

As more and more recipients of metal-on-metal hip implants experience serious adverse symptoms from the devices there will be more information on the design defects in these devices which have caused the problems. Stryker Orthopedics recalled their Rejuvenate and ABGII in 2012, only a few short years after the implants received FDA approval and began being marketed. Like the recalled DePuy ASR, as time passes more and more defects are being found in the design of the hip implants. When Stryker recalled the Rejuvenate and ABGII they stated the potential of fretting and corrosion at the neck juncture. Later it was found that corrosion could occur under the small metal trunnions located at both ends of the neck portion as body fluids became trapped underneath.

More recently it has come to light that there may be a serious mismatch between the titanium stem portion—which is coated with a proprietary mix of titanium, molybdenum, zirconium and iron mixed with plasma spray—and the cobalt and chromium neck. Studies as far back as 2002 found that corrosion is significantly higher in hip implants with mixed alloy parts versus parts which were all made of the same metal. In fact, mixed alloy hip implants were responsible for moderate to severe corrosion in 42% of hip implants as compared to 28% in implants constructed of only one metal. A study done as recently as 2012 concluded that when a titanium stem and cobalt and chromium adapter sleeve were mixed, a galvanic reaction which produced corrosion was much more likely. While it is theorized that the problem may occur because the cobalt and chromium components are much harder, scientists have not yet found a definitive reason for this phenomenon.

Why Frictional Torque May Be a Problem in the Stryker Rejuvenate and ABGII

Frictional torque could also be an issue in Stryker’s recalled hip implant devices. Stryker’s design was considered highly innovative as it implemented a variety of parts which allowed the surgeon to choose the best sizes for the individual patient. The modular neck of the Rejuvenate fits into the stem which leads to frictional torque where the two parts meet. This torque leads to significantly more wear on the joint and, in fact, a wear analysis concluded the majority of the wear occurred at the stem and neck juncture. As the bearing diameter increases, there is also an increase in mechanical stress which has been found to cause excessive cobalt ion release. This excessive wear is also responsible for pseudo-tumor formation. Retrieved head-neck tapers from a 1992 study showed that over one-third of the head-neck tapers showed moderate to severe corrosion due to the frictional torque at the juncture.

Cobalt Toxicity Due to TMZF Coating Issues

The TMCF coating used to coat the Stryker components was meant to circumvent the issue of mixing alloys as well as offer resistance to corrosion and fretting, however data disproves that theory. Fretting and corrosion do still occur, sending microscopic metal ions into the tissue surrounding the implant and into the bloodstream. When the ions have built up in the body, metal toxicity can occur leading to such symptoms as deterioration of vision and hearing, DNA disruption, the formation of pseudo-tumors, pain, cardiovascular, renal, thyroid and neurological disorders, depression, anxiety, irritability, vertigo, skin disorders and gastrointestinal issues. The ions which are shearing away from the neck/stem juncture appear to be comprised of more cobalt than chromium. This is somewhat puzzling as in other metal-on-metal hip implants measured levels of cobalt and chromium and generally much the same, while in patients of the Stryker Rejuvenate and ABGII the cobalt levels outpace the chromium levels. It is expected that Stryker Rejuvenate hip recall lawsuits will continue to mount as those who were implanted with the recalled devices will continue to experience adverse symptoms.

What Patients Should Know Regarding the Stryker Rejuvenate Hip Recall: Theories of Design Defects Which Led to the Stryker Hip Recall

What Patients Should Know about the Stryker Hip Recall Lawsuit: Problems that Led to the Recall

The Stryker hip recall lawsuits began soon after the company’s Rejuvenate and ABGII were pulled from the market in July, 2012. The company cited fretting and corrosion at the neck juncture which could result in metal ion debris being released into the body and the necessity of early revision surgery as the reason for the recall. In addition to the reasons stated by Stryker at the time of the recall, it was later discovered that the small metal trunnions located on each end of the modular neck piece were subject to corrosion as body fluids become trapped underneath.

In addition to the corrosion at the neck juncture and under the metal trunnions, higher levels of cobalt were found to be coming from the Morse taper—a slightly angular junction between the stem and the neck. Research shows that the area where the Morse taper connects to the stem releases cobalt ions causing cross-ionization between the titanium stem and the cobalt and chromium neck. When these microscopic ions of cobalt and chromium are released into the body they can become lodged in the surrounding hip tissues or travel into the bloodstream, wreaking havoc in the body.

How the Morse Taper and Mixed Metals Contribute to Ion Release

The cup and ball joint is the one which is expected to receive the majority of the wear and the Morse taper joint should have had little to no wear, therefore no ion release. Instead, the taper joint has been found to have significant wear and is responsible for causing additional stress and fraying sending cobalt ions into the body. Corrosion has also been found to occur more often among hip implant components which are made from dissimilar metals. The Stryker Rejuvenate and ABGII are constructed with a titanium stem and a cobalt and chromium neck. Titanium has a different set of mechanical properties from cobalt and chromium plus the fact that the cobalt and chromium is a much harder metal which can result in higher levels of wear.

Over twenty years ago research was conducted to study the taper interface of 139 modular femoral components which had been removed from patients. Some of these implants were constructed of a cobalt and chromium neck and head while others were constructed of a cobalt and chromium head and a titanium neck. While the components constructed of the same metal alloys showed little evidence of corrosion, the mixed metal components showed substantial levels of corrosion. When metals are mixed, taper wear is compounded, releasing ions into the body and leading to serious medical issues. Bearing diameter may also contribute to a greater number of cobalt ions released into the body.

Stryker Rejuvenate and ABGII Hip Implants Show Wear at the Neck and Stem Juncture

A more recent analysis was done regarding how and where hip implants show the most wear. The results of this 2012 study showed the majority of excessive wear occurred at the juncture of the modular neck and stem, at the top of the notch area. Neck corrosion can occur in titanium alloy stems or full-up front tapers and can be responsible for the formation of pseudo-tumors. In some cases surgeons were removing only the neck portion during a revision surgery and replacing the neck with one made of a different substance. Unfortunately, this would not correct the issue of corrosion and metal ion debris. It is expected that Stryker hip recall lawsuits will continue to escalate as more Rejuvenate or ABGII hip implant recipients begin to suffer health problems directly related to their recalled Stryker device.

Do Stryker Hip Implants Cause Increased Metal Levels? Recalled Stryker Rejuvenate and ABGII May Cause Cobalt Metal Poisoning

An FDA warning was issued in February, 2011 which cautioned the public and physicians that metal-on-metal hip implants carried unique risks due to the potential of cobalt and chromium ion shear. Stryker Orthopedics issued an Urgent Safety Alert to all healthcare providers outlining these potential hazards in April, 2012 then issued a voluntary recall of the Rejuvenate and ABGII hip implant devices in July, 2012. One of the primary concerns centers around cobalt metal poisoning from the recalled Stryker Rejuvenate and ABGII hip systems. The symptoms of cobalt and chromium poisoning include:

·         Neurological, cardiovascular, renal and thyroid disorders

·         Disruptions in DNA

·         Bone loss, tissue destruction and death

·         Chronic or serious pain

·         Anxiety, depression, irritability

·         Loss of vision and hearing

·         Chronic headaches

·         Balance disruption, vertigo, dizziness

·         Gastrointestinal disorders

·         Memory loss

·         Skin disorders

Differences in Cobalt Toxicity between the Stryker and DePuy Hip Implants

While both the Stryker recalled hip implants and the DePuy ASR recalled implant can lead to metal toxicity, the Stryker implants are constructed differently and patients may be advised to undergo revision surgery when the levels of cobalt are much lower than those of a DePuy patient—even at levels of 2-3 parts per billion.  If a person without a metal hip implant were to go to their doctor and request a blood test to measure metal in the bloodstream the amount found in a healthy person would range from .19 to .4 parts per billion—an amount smaller than a grain of sand. An amount of 7 parts per billion or higher are definite cause for concern and, aside from the symptoms listed above, can cause constant pain in the hip region, the destruction of bone, tissue and muscle and muscle masses under the skin known as pseudotumors.

A revision will generally be recommended for a patient with a metal-on-metal hip implant who measures cobalt concentrations of 19 parts per billion. The difference between the DePuy ASR and the Stryker ABGII and Rejuvenate as far as levels of cobalt and chromium is that in a DePuy patient if the cobalt level is 20, 30, 40 or any other number, the chromium level is likely to be much the same. Stryker patients, however, are seeing a much greater disparity between the chromium and cobalt levels with the cobalt levels being much higher. The theory behind the higher cobalt levels in Stryker Rejuvenate or ABGII patients ties to the design of the Stryker models.

The “wear” in the Rejuvenate and ABGII comes from the stem and neck rather than the cup and ball portion of the joint—a surface which was not supposed to undergo wear. A Morse taper—a slightly angular junction which the physician hammers into the stem until snug and locked tightly—is implemented into the design of these two hip devices. At the location the Morse taper meets the stem, cobalt and chromium ions are released which in turn leads to cross ionization between the titanium stem and the cobalt and chromium neck. It is believed the neck portion is releasing more cobalt than chromium ions although scientists are not entirely certain why. In any case, the Morse taper has apparently created an added stress location which sends cobalt ion debris into the body of the patients.

Why the Loss of Muscle is More Serious than Loss of Bone

While the loss of bone, muscle or tissue is always a serious event, bone can be recreated using bone stock and cement. Muscles, however, cannot be artificially recreated therefore when any of the roughly 640 muscles in the body are killed through cobalt exposure, the muscle is gone forever. While the surrounding muscles can be strengthened through exercise enough to carry the loads placed on them as a result of the destroyed muscles, this extra load can also potentially lead to a burning sensation, a constant limp or gait, or, in extreme cases, the necessity of a walker or wheelchair for the remainder of the person’s life.  

FDA Approval for the Rejuvenate and ABGII

Both the Rejuvenate and ABGII gained FDA approval in 2009 through a process known as the 510k. This approval process requires minimal testing and must only meet the criteria of being substantially equivalent to a product already on the market. Stryker had no idea the Morse taper would wear in the way it has once implanted, causing cobalt ions to flood the body because there was very little in-depth research prior to marketing. Once the cobalt levels have become elevated in a patient with a Stryker recalled hip implant, it is likely the patient’s doctor will recommend revision surgery to remove the dangerous implant and replace it with a safer alternative.

Stryker Rejuvenate Hip Recall: Symptoms of ALVAL and Elevated Cobalt Levels

Hip implant recipients who received a metal-on-metal device may have a significant number of potential health issues to be concerned with. When the metal components of the implant rub against one another microscopic metal ions can be released into the body. This can be a serious matter for any patient however some patients are more sensitive to metals than others. This may explain why some hip implant patients with a relatively low amount of metals in the body can become extremely ill while others with much higher levels may have few adverse symptoms. The generally accepted “cutoff” point for the danger level of metals is seven parts per billion (The normal, healthy person will have levels between .19 and .4). This is a rather arbitrary number in that lower numbers can be just as dangerous in a recalled Stryker Rejuvenate or ABGII because of their unique design.

While any patient with symptoms of metal poisoning should definitely undergo blood tests to confirm the levels of metals although interpreting those results can be tricky. There are a number of variables which factor into deciphering the metal levels in a hip implant recipient including the patient’s age and gender, symptoms and, of course, the specific type of hip implant. The typical symptoms of metal poisoning include: gastrointestinal, renal, thyroid, cardiovascular and neurological issued, skin rashes, elevated risks of cancer, pseudo-tumors, DNA mutations, vertigo, vision and hearing loss, depression, anxiety, irritability and memory loss.

Metal Sensitivities Which Contribute to Hip Recall Symptoms

Metal sensitivities can contribute greatly to the symptoms experienced by those with metal hip implants. The Journal of Investigative Dermatology puts the number of people who experience some degree of sensitivity to nickel at approximately thirty percent. Some of those people will be severely allergic to nickel and will have violent reactions to virtually any exposure to nickel. Hip implants which are constructed of cobalt and chromium contain around one percent nickel. When the metal ions shear away from the implant, a certain number of nickel ions will also be transported throughout the body. A person with a severe nickel allergy who undergoes artificial hip implantation with a device made of cobalt and chromium could suffer extreme damage to the liver and kidneys.

Others who have metal sensitivities but not in the extreme can initially have fairly vague symptoms such as mild swelling, redness, fever, eczema and rashes with no other explanation. As time goes on and more metal ions enter the hip tissues and bloodstream, the allergic reactions will increase in severity. Chronic pain will occur as well as significant inflammation of the hip tissues. These in turn can lead to loss of mobility as well as implant failure as it pulls away from bone. Those patients who experience this level of hip recall symptoms may have little choice but to undergo painful and potentially risky revision surgery.

  

How Metal-on-Metal Hip Implants Can Lead to ALVAL

An extreme hypersensitive response to a metal-on-metal hip implant is known as ALVAL or Aseptic Lymphocyte dominated Vasculitis Associated Lesion. While doctors do not completely understand the ALVAL phenomenon it has been suggested that there may be a link between bone loss and ALVAL. When a patient has suffered chronic groin pain—particularly when that pain restricts the normal day-to-day activities—ALVAL may be suspected and tests for infection considered. Should the groin pain persist yet infection be absent, the physician may nonetheless recommend revision surgery and a new implant of a different substance.

When ALVAL is suspected the doctor will perform an exam, take a thorough patient history as well as x-rays and MRI. During a revision surgery a microbiological and histological analysis can prove the presence of ALVAL. Many doctors consider ALVAL to be under-diagnosed because of the fairly non-specific symptoms. One specific characteristic of ALVAL lies in the painful straight leg raise which is likely due to excess fluid around the joint. Among patients suspected of suffering from ALVAL, fluid withdrawn from the hip is generally a greenish gray color and a thicker viscosity. Any recipient of a metal hip implant such as the recalled Stryker Rejuvenate or ABGII who has hip recall symptoms should see their physician as soon as possible. Those with no overt symptoms should also have regular testing done to determine the levels of metals in their body.