TJA Study: Females Have Higher Sensitivity to Metals

In a post-total joint arthroplasty (TJA) group of patients with no evidence of infection, what happened to the females versus the males as far as metal sensitivity?

A new study from Chicago, “Females with Unexplained Joint Pain Following Total Joint Arthroplasty Exhibit a Higher Rate and Severity of Hypersensitivity to Implant Metals Compared with Males: Implications of Sex-Based Bioreactivity Differences,” was published in the April 19, 2017 edition of The Journal of Bone & Joint Surgery.

Joshua J. Jacobs, M.D., the William A. Hark, M.D., Susanne G. Swift Professor and Chairman in the Department of Orthopedic Surgery at Rush University Medical Center in Chicago told OTW, “Rush researchers have been investigating the biological implications of total joint replacement for decades, including the potential for an adaptive immune response (allergy) to metal degradation products. This is the latest study exploring the potential clinical implications of metal allergy, as determined by lymphocyte transformation testing (LTT).”

The authors write, “Are more aggressive adaptive immune responses, such as metal sensitivity, a biological factor that contributes to the greater risk of aseptic implant failure among females compared with males?”

“We hypothesized that, in a cohort of subjects referred for metal-sensitivity testing because of joint pain following TJA with no evidence of infection, females would demonstrate a higher rate and a higher level of sensitization to implant metals compared with their male counterparts as determined by a metal-lymphocyte transformation test (metal-LTT). We tested this hypothesis by retrospectively analyzing the rate of metal sensitization (i.e., metal allergy) to cobalt (Co), chromium (Cr), and/or nickel (Ni) in 1,038 male subjects and 1,575 female subjects with unexplained pain following TJA who were referred for metal-sensitivity testing.”

Dr. Jacobs noted, “The sexual dimorphism observed in the severity of pain as well as the increased prevalence and magnitude of lymphocyte responsiveness in women, as measure by LTT, may help explain the higher rates of implant failure in women. There are indeed sex-based differences in the immunological response to joint replacement implants. However, the clinical significance of these differences has yet to be established. At this juncture, there is not sufficient evidence to change practice as a result of these findings.”