January 13, 2015 - The Dangers of Stryker Revision Surgery
ATTENTION STRYKER HIP IMPLANT RECIPIENTS - You may be entitled to compensation under the recent Stryker Hip Settlement Agreement...
Introduction - Surgery Issues from the Morse Taper
Unlike DePuy ASR patients, whose cobalt and chromium levels are generally very similar, patients with a Stryker ABGII or Rejuvenate could see a wide variance between cobalt and chromium levels, with the cobalt level being significantly more elevated. The likely cause of this disparity is that the highest levels of “wear” occur in the neck and stem of the Rejuvenate and ABGII rather than the cup and ball portion of the joint. The design of these two Stryker devices also implements a Morse taper between the stem and neck; the Morse taper is an angular junction which is hammered into the stem until snug, then hammered again to ensure it locks into place.
Some believe that where the Morse taper meets the stem, cobalt and chromium ions are released, causing cross-ionization between the titanium stem and the cobalt in the neck. In other words, instead of providing extra “give” and adapt to patient sizes, the Morse taper has created additional stress, leading to micro-motion and fraying, and the release of metal ions into the body. Because the Morse taper is not considered a “wear” joint, there should not be this release of metal ions, yet it exists.
Metallosis and Metal Toxicity Health Risks Associated With the ABGII and Rejuvenate
Every person will have somewhat different tolerance levels to heavy metal build-up in the body; relatively low levels of cobalt and chromium in some patients can lead to serious, adverse health symptoms and the necessity of hip revision surgery. Conversely, some patients with extremely high levels of cobalt and chromium in their bodies have yet to experience adverse effects. Generally speaking, any level of cobalt over 5 parts per billion is considered toxic; some patients with metal-on-metal hips have tested at many times that level, literally destroying their health.
While every person with a Rejuvenate or ABGII hip implant will react to the device differently, many patients have experienced symptoms of metallosis and/or metal poisoning. Metallosis brings symptoms such as the destruction of tissue and bone, severe inflammation, groin and thigh pain, blackened tissue, chronic and sometimes severe hip pain, and an implant which may fail completely, requiring revision surgery. Metal toxicity or metal poisoning can cause gastrointestinal disorders, loss of hearing and vision, loss of short-term memory, reproductive disorders, cardiovascular and neurological issues, renal and thyroid problems, disruption of DNA, the formation of pseudo-tumors, vertigo, increased lymphocytes, anxiety, depression and irritability, certain types of cancers and skin rashes.
The Dangers of Stryker Revision Surgery
Surgeons generally consider the removal of a Rejuvenate or ABGII to be much more complex than the removal of other types of metal hip implants. Because it takes the surgeon so long to “dig” the stem from the femur bone, the time the patient is on the operating table can stretch to four or five hours. Patients who are on the operating table for this length of time are exposed to infection, excess bleeding and nerve damage. When the ABGII or Rejuvenate is removed due to severe metallosis, hip failure or cobalt and chromium poisoning, the neck piece must be removed with a special modular neck extractor. Once the neck is removed, the stem will be removed, using a locking arm which engages the taper, pushing the stem from its position in the femur bone.
Particularly in those with a Rejuvenate device, the stem is much more difficult to remove because it is longer, and implanted more deeply into the bone. In some patients, the femur bone will literally shatter, leaving the surgeon unable to complete the revision surgery and the patient in a wheelchair until the bone can be rebuilt. Recovery time for a Rejuvenate or ABGII revision surgery can be as long as six weeks, leaving patients unable to return to work or continue their normal activities. The mortality rate for revision surgery in patients with a Rejuvenate or ABGII is as high as 2.5%, as compared to a 1% mortality rate for the original hip implant surgery.