In their search for answers regarding why women seem to be at a higher risk of complications following joint replacement surgery, investigators note that an increased rate of hypersensitivity to the metals contained in the implants may be a contributing factor.
According to the study, published recently in The Journal of Bone & Joint Surgery, investigators reviewed data on 2,613 patients who were evaluated for unexplained joint pain after undergoing total hip and/or knee replacement surgeries.
Among these patients, per a media release from Wolters Kluwer Health: Lippincott Williams and Wilkins, women were more likely than men to test positive for metal sensitization.
All the patients who were investigated for unexplained joint pain postsurgery received a blood test—called a lymphocyte transformation test (LTT)—to evaluate their immune cell sensitization to metals.
The test results indicate that 49% of the women were sensitive to the metal, compared to 38% of the men. When the researchers used a more stringent definition of sensitization, the difference was still apparent—this time, 25% of the women reported sensitivity, versus 18% of the men. In addition, among patients with positive LTT results, the severity of metal sensitivity was greater in women.
Prior to undergoing the LTT test, 29% of the women in the study said they had allergic skin reactions to metals, compared to 4% of men.
“This supports both our hypothesis and previous reports that females may have a higher risk of adverse responses to implant metals,” notes study author Nadim J. Hallab, PhD, and colleagues from Rush University Medical Center in Chicago, in the release.
There is a possibility that the higher rate of complications after total joint replacement in women may have an “adaptive immunological basis,” Hallab adds. But it’s still unclear whether the sex-related difference in immune sensitization is related to intrinsic biological factors, such as hormones, or to environmental factors, such as exposure to metals in jewelry or cosmetics, per the release.
The study also couldn’t determine whether the metal sensitivity was a pre-existing condition, was induced by the metal-containing joint implants, or both.
However, Hallab concludes, “We feel these results add credence to the utility of metal allergy LTT testing for diagnosing orthopaedic patients who demonstrate a history of dermal metal allergy or have an implant with idiopathic pain and/or peri-implant inflammation.”
[Source(s): Wolters Kluwer Health: Lippincott Williams and Wilkins, Science Daily]