[Prospective study of the significance of contact sensitization caused by metal implants]

Allergies caused by metallic implants are often thought to be a reason for postoperative complications like bone necrosis or loosening of the prosthesis.

In a prospective study, we investigated allergic sensitivity against components of stainless steel implants, including titanium, in 112 patients shortly before surgical operation. The same tests were then repeated in 100 of these patients exactly one year after operation. There were three different kinds of procedures: 1. titanium implants, mainly total hip replacements, 2. regular steel implants, 3. surgery without any implants (control group). Any differences from the process of regular healing were regarded as postoperative complications.

A sensitivity against nickel (Ni) was diagnosed in three of these 100 patients (3%) before surgery. These patients, of whom two received a nickel-containing implant and one a titanium arthroplasty, did not show any postsurgical complications. Furthermore, three patients (3%) acquired a new sensitivity against metals during the study-interval of one year. Two of these three patients were women, who developed a postsurgical sensitivity against nickel or chrome but got titanium arthroplasties, which did not contain any nickel. These two women wore metal-containing jewelry, which might be the reason for the newly acquired metal-sensitivities, and both showed postsurgical complications. The third patient, who has developed a postsurgical sensitivity against components of his steel arthroplasty, did not reveal any complications.

We conclude that the rate of allergic sensitization against metal-components of arthroplasties is low in our patients. Additionally, skin-sensitivity against components of alloys and platings was not associated with a higher rate of postsurgical complications in our patients. We did not see any sensitivity against titanium. In conclusion, metallic implants are not a cause of allergies to a relevant extent, nowadays.