Implant allergy

Osteosynthesis materials or artificial joint replacement make part of clinical routine. In case of complaints mostly mechanical causes or infections are found. Metals like nickel, chromium and cobalt or bone cement components like acrylates and gentamicine may however potentially cause intolerance reactions to implants. Correspondingly, eczema, delayed wound/bone healing, recurrent effusion, pain or implant loosening have been described as manifestation of implant allergy. In contrast to the high incidence of cutaneous metal allergy, allergies associated with implants are rare. Diagnosis of metal implant allergy is based on excluding differential diagnoses – in particular infection – and on a combined approach of allergological diagnostics by patch test and histopathology of periimplant tissue. Risk factors for allergic sensitization to implants or triggering periimplant allergic reactions in the case of preexisting cutaneous metal allergy are unknown. Despite the risk of developing complications being unclear, titanium-based osteosynthesis materials are recommended for metal-allergic patients and the use of metal-metal couplings in arthroplasty is rather not recommended for such patients. If a regular, potentially applicable CoCr-polyethylene articulation is preferred, the patient has to be well informed and has to give his written consent.