Allergy to endoprostheses.

This paper describes a study of hypersensitivity and tissue reaction to loosened metal implants in 40 patients who underwent repeated hip arthroplasty. Metal sensitivity was tested using a standard cutaneous patch test. Nine patients were positive for chromium, nickel, cobalt, metal rust, endoprosthesis scrapings or combinations of these allergens. Patients with positive or negative patch test did not differ in terms of their age, sex, primary diagnosis, number of endoprosthesis revisions, length of implant function, presence of other metal parts around the implant, circulating immunocomplexes, and histological appearance of the tissue around the implant. In conclusion, stainless steel endoprostheses are safe for revised hip arthroplasty, and hypersensitivity to metals probably does not play a significant role in the loosening of endoprosthesis.