The recent rash of
metal-on-metal hip device recalls as well as the ensuing lawsuits against
manufacturers who appear to have more interest in profits than in patient
safety were the topic of discussion at a March 19, 2013 meeting among orthopedic
surgeons. This conference, held in Chicago, of the American Academy of
Orthopedic Surgeons centered on determining whether judicious use of MRIs could
predict soft tissue damage in hip implant recipients before irreparable damage
was done.
While the FDA has issued
updated guidelines for recipients of all-metal or partial metal hip implants
which recommended regular physical exams, blood testing, x-rays and MRIs, many patients
are not receiving the MRI test. Any unusual pain and swelling in the hip area
following artificial hip implantation is cause for concern and may indicate
device failure. Research done on seventy patients who underwent revision
surgery for replacement of a defective hip device was discussed by the
physicians at the AAOS conference. This research indicated that the superior
imaging capabilities of the MRI could more easily identify early tissue damage
among implant recipients.
Such early identification can
minimize the levels of tissue necrosis and bone loss prior to the revision
surgery. When extensive bone and tissue loss is present, revision surgery
becomes much riskier for the patient and much more challenging and complex for
the orthopedic surgeon. Although metal-on-metal hip implants as well as the
designs which implement partial metal components—such as the Stryker Rejuvenate
and ABG III—were marketed as providing extended life and greater durability for
patients, those promises have not materialized.
Metal implants which were
believed to be superior to their ceramic and polyethylene counterparts have
been shown to exhibit early failure as well as serious, long-term injuries and
illnesses. When microscopic metal ions shear away from the metal components
during periods of activity, those tiny cobalt and chromium shards can lodge
into surrounding tissues or enter the bloodstream of the patient. Inflammation,
chronic pain, tissue necrosis and bone loss as well as symptoms of metal
toxicity can occur. Cobalt and chromium toxicity can lead to:
·
Neurological, cardiovascular, renal, thyroid and
gastrointestinal disorders
·
Depression, anxiety, irritability
·
Memory loss, vertigo and other balance issues
·
Skin problems
·
Vision and hearing loss
·
DNA disruption
·
The development of pseudotumors
A statement issued at the
conference recommended early evaluation for patients with metal hip
replacements. Earlier recognition and evaluation of patients with metal hip
replacements can allow treatment prior to significant levels of damage to the
patient. Specific treatments and diagnostic methods used when patients
experience pain and discomfort were also detailed by the AAOS as well as a time
frame for beginning treatment and performing revision surgery. The FDA’s updated
guidelines have proposed new regulations which would require clinical trials
and proof of implant safety prior to marketing hip implants to consumers. This
is considered to be a positive step in holding hip implant manufacturers
responsible for deficiencies and dangers in their hip devices. The bottom line
for those with a metal hip implant is that an MRI can potentially detect tissue
and bone damage before it has reached extreme levels.
t a �} P| lure rate may actually be as high as 40% as opposed to
the failure rate of a traditional implant of between 4-5%.
The risks of revision
surgery—particularly for the Stryker ABG II and Rejuvenate—are higher than the
risks of the original surgery and even higher than the risks for other implant
revisions. Surgeons dislike performing revision surgery to remove an ABG II or
Rejuvenate because of the method of implantation, yet there may be little
choice in the matter if a patient begins experiencing symptoms of implant
failure or metal toxicity. Part two of this article will more fully detail the
surgical procedure for revision of a Stryker ABG II or Rejuvenate hip implant.
