Cobalt Poisoning

Cobalt Poisoning from Hip Implants

Cobalt Chrome is used in the manufacture of various hip replacement components. A number of studies have confirmed that cobalt and chromium ion’s are released into the surrounding bone and tissue causing local detrimental effects. However, Cobalt and Chrome ions are toxic to other tissues and body functions.

Review of the available literature suggests that all patients with Metal on Metal (MoM) hip replacements made of cobalt chrome are likely to have elevated to toxic levels of cobalt and chromium ions, whether they are aware of problems localized on the hip or more wide-ranging systemic problems.

A metal-on-metal hip implant is usually made of chromium and cobalt, and consists of an acetabular cup that’s implanted into the hip with a ball joint that connects to the leg. Cobalt poisoning results when the metal components of an implant begin to wear and microscopic metal shards are absorbed into the blood stream and infiltrate the organs. The tissue damage that results from cobalt poisoning can complicate future revision surgeries intended to replace the damaged metal-on-metal hip implant.

A New York Times report published in March 2010, states that metal-on-metal hip implants have been used in about one-third of the approximately 250,000 hip replacements performed annually in the USA. However, many leading orthopedic surgeons have reduced or stopped use of these devices because of concerns that they can cause severe tissue and bone damage.

When they wear, metal particles from these hip implants can infiltrate organs and tissues, and may even create large, painful cysts. The limited studies conducted so far on metal-on-metal hip implants estimate that 1 to 3 percent of implant recipients could be affected by the problem.

That may not sound like a whole lot but that is up to 7,500 people per annum – so you are one of them then that matters a whole lot!!!

An October 2010 article published in The Journal of Bone and Joint Surgery linked metal-on-metal hip implants to cobalt poisoning (see below).

The article described two patients from Alaska who developed the condition after receiving DePuy ASR metal-on-metal hip implants. Both were “fit, well, forty-nine-year-old men at the time of metal-on-metal arthroplasty with ASR implants,” the article said. Thirty months after surgery, one patient’s blood cobalt level was 122 µg/L, while the second patient’s measured 23 µg/L one year after receiving a metal-on-metal implant. According to the study’s authors, normal serum cobalt level is 0.19 µg/L, and 95 percent of those who are unexposed to cobalt have a value of <0.41 µg/L.

Within one year of the hip implant surgery, both patients experienced symptoms of persistent hip pain and shortness of breath as the microscopic metallic particles from the hip implant were released into the bloodstream and tissues. Two years after the hip implantation, the patients in the study experienced even more symptoms of cobaltism, which can include irritability, fatigue, tinnitus, hearing loss, headaches, loss of coordination, cognitive decline, and depression. After revision surgeries, the patients’ symptoms improved. The authors called for a larger group study to define the prevalence and spectrum of cobalt poisoning due to hip replacement surgery.

Hip replacement patients should be relatively pain-free three months after surgery. Any new pain or increase in pain at that point should be promptly communicated to your surgeon, as it may indicate a complication.

Signs that you may be the victim of a failed metal-on-metal hip implant and cobalt poisoning include:

•      Metal-on-metal hip implant failed prematurely.
•      Pain and inflammation in the hip area.
•      Swelling, Extreme Pain & Discomfort
•     Dislocation of Implant
•     Clicking, Popping or Grinding
•     Loosening of the Implant
•     Unexplained Hip Pain
•     Thigh Pain or Groin Pain
•     Pain with Walking
•     Pain Rising from a Seated Position
•     Pain with Weight Bearing
•     Difficulty walking due to the pain in the hip that has been replaced.
•     Non-cancerous tumors (cysts) since receiving your metal-on-metal hip implant?

Cobalt Poisoning

Cobalt poisoning is extremely serious.

If it is left untreated, it can result in:

1. Tinnitus (ringing in the ears)
2. Vertigo
3. Deafness
4. Blindness
5. Optic nerve atrophy
6. Convulsions
7. Headaches
8. Peripheral neuropathy
9. Cardiomyopathy
10. Hypothyroidism
11. Cognitive problems, including dementia.

Key Website

This is a key website to look up and some of the key points are highlighted below: http://www.cobalt-poisoning.com/

This particular paper highlights the issues in two patients:

Cobalt Toxicity in Two Hip Replacement Patients [click here to download]

Patient A, a fit, otherwise healthy, 49 year-old male received a MoMHA for osteoarthritis. An echocardiogram performed prior to his MoMHA showed normal myocardial function. At 3 months post-op, he complained of bilateral axillary rashes. At 8 months post-op, he reported unaccustomed shortness of breath. Pulmonary function tests and allergy testing for metals were normal. At 18 months post-op, he reported anxiety, headaches, irritability, tinnitus, and hearing loss. An audiogram confirmed high-frequency hearing loss. At 30 months post-op, he reported pain interrupting sleep, hip creaking, hand tremor, diminished coordination, slow cognition, poor memory, and lassitude. At 36 months post-op, a non-refractive loss of peripheral visual acuity was noted; at this time, his SCoL was 122 mcg/L.

The patient was indicated for revision surgery due to progressive hip pain and high SCoLs. An echocardiogram performed prior to the revision showed diastolic dysfunction. The revision was performed 43 months after the first surgery. At revision surgery, the periprosthetic tissues showed necrosis and staining with metal debris and visible wear of the retrieved bearing. At 1 month post-revision, Patient A’s SCoL was 14 mcg/L. At 6 months post-revision, he reported that all symptoms were improved except the visual changes.

Patient B, a fit, otherwise healthy, 49 year-old male received a MoMHA for a failed arthroplasty. At 12 months post-op, he complained of mental fog, memory loss, vertigo, hearing loss, groin pain, rashes, and breathlessness. At this time, his serum cobalt level was 23 mcg/L. At 18 months post-op, an echocardiogram showed diastolic dysfunction. He was observed until 40 months, when revision surgery was performed for progressive hip pain. Just before the revision, Patient B’s SCoL was 23 mcg/L. At revision surgery, the periprosthetic tissues showed necrosis and staining with metal debris and his retrieved bearing showed visible wear. At 2 days post-revision, his SCoL fell to 11 mcg/L. At 3 months post-revision, his symptoms were improved.

Related articles

• ‘Metal on metal’ hip implants leave some recipients in pain, at risk (earlsview.com)
• Bruce Greenfield may be the last New Zealander implanted with a faulty hip joint (earlsview.com)
• How Long Do Hip Replacements Last? (earlsview.com)
• Options for Hip Replacements – different materials (earlsview.com)
• Associate Professor Michael J. Neil – Doesn’t Recommend Resurfacing (earlsview.com)