Heavy Metal Allergies

Joint replacement patients benefit from metal allergy testing prior to implant surgery

(RxWiki News) A new hip or knee may be what you need to set yourself free from arthritis pain. Many implants are made of metal. So, what happens if you are allergic to metal?

Patients should be tested for metal allergies before undergoing surgery to implant a prosthetic joint or bone. If a patient is tested for metal allergies after implantation, the surgeon and patient should decide together whether to remove the implant.

"Get tested for allergies before joint or bone replacement surgery."

In a recent study, Natasha Atanaskova Mesinkovska, M.D., Ph.D., of Cleveland Clinic, and colleagues wanted to see if allergy tests - or patch testing - had an effect on surgeons' decisions and patient outcomes.

According to the authors, "More than one million lower extremity total joint replacements are completed yearly in the United States, and this number is expected to increase."

"Nickel is a commonly used metal in alloys because it grants necessary strength and durability to the implant. At the same time nickel is the leading cause of contact dermatitis associated with metals, affecting up to 19 percent of the population evaluated for testing," they explain.

For their study, Dr. Mesinkovska and colleagues looked at information on 72 patients who underwent joint or bone implant surgery and were tested for metal allergies. Of these patients, 31 were tested for allergies before surgery while the other 41 were tested after surgery.

The researchers observed 21 instances of positive test results (meaning patients were allergic) among the patients tested before surgery.

In all cases where testing was done before surgery, a positive test result influenced the decision-making process of the surgeon. These patients received implants without the metals to which they were allergic.

No patient who received an allergen-free implant had allergic outbreaks on the skin. They also did not develop early joint loosening.

"The findings of this study support a role for patch testing in patients with a clinical history of metal hypersensitivity before prosthetic device implantation," the authors write.

"The decision on whether to remove an implanted device after positive patch test results should be made on a case-by-case basis, as decided by the surgeon and patient," they write.

More than half of the patients who were tested after surgery had a positive test result. In most of these cases, patients went through a post-surgery allergy test because they were experiencing chronic pain in the site of the implant.

Of the patients with a positive allergy test after surgery, six had their implants removed. After implant removal, these patients were free of their symptoms. Patients who did not have their implant removed continued to have problems.

"The results of this study support the value of patch testing for patients with a clinical history of metal hypersensitivity before surgical implant in bone or a joint as a safe measure to avoid complications," the authors conclude.

"The study confirms the need for surgeons and dermatologists to work together and establish guidelines with a goal to identify patients who would benefit from revisions of previously implanted metal," they write.

The results of the study are published in the Archives of Dermatology.

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Review Date: 
February 28, 2012