Novel test for nickel allergies may improve joint replacement surgery

A team of American scientists has developed a new technique that will enable rapid and accurate screening for allergies in patients about to undergo joint replacement surgery. This simple blood test could prevent a sizeable proportion of patients from experiencing intense pain and discomfort during their convalescence and subsequently been forced to undergo corrective surgery.

Allergies to artificial joints constitute an important clinical burden worldwide. Commonly performed in elderly, arthritic patients, joint replacements can significantly improve a patient’s independence, mobility and quality of life. However, as many as 10% of patients who undergo knee and hip joint replacement surgery experience little improvement in their condition. In many cases, this can be ascribed to an allergic reaction against the composite metals of artificial joints (notably nickel) which occurs many weeks or months following surgery. Such a reaction typically manifests as itching, pain and discomfort at the site of the artificial joint and throughout the rest of the body. A second bout of surgery is needed to remove the offending joint and replace it with a non-allergenic alternative.

More than 750,000 Americans underwent hip and knee joint replacements in 2009 alone. The demand for these surgeries is projected to increase precipitously in line with our ageing population; by 2030, as many as 11,000 Americans will undergo hip or knee joint replacement surgery every day. Although doctors can screen for allergies prior to surgery using skin patch tests, the week-long duration of such a test renders this procedure utterly impractical for patients. Dr Karin Pacheco and colleagues at National Jewish Health in Denver have addressed the urgent clinical need for an accurate and rapid method of pre-operative allergy detection by creating the world’s first blood test screening for nickel allergies. The team is hopeful that the cheap and effective test will soon be validated and approved for clinical use.