Should You Take This Test Before Joint Surgery?

When women undergo joint replacements involving metal implants, they’re more likely than men to find them painful at some point after surgery. One reason is that blood tests reveal that women are more likely than men to have immune sensitivities to metals. For example, it is estimated that up to 17% of women and 3% of men have an allergy to nickel, the metal most likely to cause adverse reactions.

Recent finding: In a study at Rush University in Chicago involving 2,600 men and women (average age 62) who had undergone total hip and/or knee replacements, researchers concluded that this greater sensitivity to metals accounted for the increased pain that some women experience after joint replacement. The findings have implications for those undergoing other procedures as well, such as the implantation of IUDs.

Before undergoing an implant procedure: Ask your doctor what metals are present in the implant. If you have a metal sensitivity (for example, you develop a rash, itchiness or bumps on the skin when wearing certain jewelry) or suspect that you may have one, ask for a metal-LTT analysis, a blood test that can identify your body’s reactions to various metals. (This is not the same as the “skin patch test,” which I do not recommend for metal sensitivity testing prior to orthopedic surgery. Measuring skin reactivity to metals upon exposure with a skin patch may be inaccurate if you have eczema or other skin conditions. And skin testing may actually cause metal sensitization in someone previously not sensitive.)

If the metal-LTT test, available from Orthopedic Analysis,* a diagnostic testing company, shows sensitivity, your surgeon may be able to choose an implant made with a different metal. Titanium, for example, causes fewer reactions than cobalt. Switching to a different implant will minimize the risk for pain and inflammation-induced bone loss that may result in the loosening of the implant and require corrective surgery. A blood test for nickel allergy is offered by National Jewish Health in Denver.

Testing for metal sensitivity is also recommended for people with an existing implant who have pain and inflammation even though infection and surgical error have been ruled out. Besides nickel, cobalt and chromium are the metals most frequently implicated in allergic reactions.

Editor’s Note: If you’ve got knee pain but aren’t sure that surgery is right for you, certain exercises may give you the relief you’ve been looking for.