Titanium Allergy Or Not? "Impurity" of Titanium Implant Materials (Report‪)‬

1. INTRODUCTION Numerous studies on allergic reactions to synthetic materials have been carried out, in particular on allergic reactions to metallic components that are also used in orthopedic surgery. In case histories, localized or generalized eczemas, urticaria, persistent swelling, sterile osteomyelitis and cases of aseptic implant loosening are described as examples of allergic reactions to metal implants [1-28]. Nickel, cobalt and chrome are the classic contact allergens [1,2,11,29-32]. However, in contrast to the sensitization ratio of up to 12 percent of the general population to nickel and of up to 5 percent to cobalt and chrome [24,32], only a few cases of allergies to implant materials have been documented. Precise details on the frequency of such reactions are presently not available. Furthermore, up to now, the frequency of allergic reactions occurring in the peri-implant region, without any prior patch test reactions, has not been established. For example, inflammatory infiltrations of the peri-implant region displaying characteristics of late-type allergic reactions were found in a number of patients undergoing revision operations related to complications [2]. Thomas [24] and Willert [27] published cases of endoprosthesis loosening with accompanying T-lymphocyte-dominated immune reactions in the peri-implant region. In the 1970s, obvious allergic reactions to the cobalt-chrome alloy components of the McKee-Farrar prosthesis underwent scrutiny for the first time [3,11]. In case of a nickel allergy, individual responsiveness can be very diverse, with even minute quantities of nickel causing contact eczemas in sensitive patients [3,11,32]. Their high resistance to corrosion, the absence of any carcinogenic risk, their excellent bio-compatibility and their lack of sensitization make titanium implants or titanium alloy implants the recommended alternative for patients with nickel, cobalt or chrome allergies [33,34]. Admittedly, there are also reports of incompatibility reactions to titanium materials [10,25,35-42]. In his study, Walsh [42] found several eyeglass frames made of a titanium alloy to contain nickel traces. Likewise, Suhonen [41] documented allergic contact dermatitis caused by titanium eyeglass frames. However, in Suhonen's case, palladium was established as the causative factor.