Implant allergy

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An implant allergy (synonymous with endoprosthesis intolerance ) is a previously unproven painful inflammation of the synovia (joint mucosa), osteolysis (bone dissolution) and aseptic loosening of an endoprosthesis due to pre-existing type IV sensitization ( allergy of the so-called late type according to Coombs and Gell ) to implant components.

prophylaxis

In order to prevent the risk of a possible implant allergy, it is possible to implant a joint replacement made of a titanium alloy, with very good results in the medium term. However, the mechanical resistance of this endoprosthesis is lower than that of a prosthesis made of a chrome-cobalt-nickel alloy, which can ultimately lead to the prosthesis having to be replaced prematurely. In addition, after a few years, components from the alloy can get into the body. In patients with a nickel allergy , even after implanting a "pure" titanium prosthesis, an allergic reaction can occur at some point, as titanium prostheses also contain the slightest amount of nickel due to the manufacturing process. Surface-coated implants are another alternative. The standard material is coated with a zirconium nitride or titanium nitride layer in a PVD process . The surface treated in this way is very hard and, when tested in the biomechanics laboratory, generates less abrasion than the standard materials (CoCrMo).

An allergy to implant components ( cobalt , chromium , nickel , etc.) can be determined using a lymphocyte transformation test (LTT) and a patch test . The extent of an allergic reaction to the implant as well as the components of the bone cement used and other additives depends not only on the material properties but also on the individual willingness of the person concerned to react. Not every person with an allergy reacts in the same way.

literature