Figure 2.

Implant-related hypersensitivity is influenced by multiple factors. Delayed type hypersensitivity (DTH) reactions to implant materials cannot be attributed to a single cause. Multiple factors influence the development and consequence of hypersensitivity, many of which are yet to be identified. Bone marrow, as a T cell harboring, possibly secondary lymphoid tissue, has the potential to develop DTH reactions when exposed to implant materials. In addition, today's arthroplasty cohort is younger, more active and thus more demanding with regard to implant longevity, and apparently more prone to allergies than the previous generation of implant carriers. These include allergies against nickel and cobalt, metals that have shown to be frequently present in the proximity of endoprostheses at the time of revision surgery.