A new study has found that pain or discomfort in an artificial joint may be due to allergy to one of the implant materials. These recent finding were presented at the American Academy of Orthopaedic Surgeons (AAOS) 2014 Annual Meeting. Researchers looked at the incidence of allergic reactions primarily in knee replacements and hip replacements. Evaluation of data has shown that around half of those with unexplained implant failure were allergic to one of the materials in the implants. Unsurprisingly, three quarters of affected individuals had a history of allergic reactions. The most common allergic reaction was to nickel, followed by cobalt, nickel and cobalt combined; chromium, any bone cement extract, bone cement, and benzoyl peroxide. Of the allergic patients who underwent revision surgery to change their implants and remove the allergen, 78% reported that they were "moderately" or "a lot" better. The researchers have suggested that perhaps a skin patch test to check for allergies should be done in patients considering joint replacement surgery. This can help to improve the odds of better post surgical outcomes. Allergies are very common, but most of us don’t consider potential allergic reactions to materials used in artificial joints. An allergic reaction in a replaced joint can cause pain and stiffness, negating the benefits of the surgery. Nickel allergies are the most common, affecting around 15 percent of the population. If you’re considering joint replacement surgery, perhaps it’s a good idea to discuss your allergies with your prospective surgeon. American Academy of Orthopaedic Surgeons (AAOS) 2014 Annual Meeting: Abstract 120. Presented March 11, 2014.