Metal sensitivity in patients with metal-to-plastic total hip arthroplasties.

Out of 134 patients patch tested after total hip replacement (metal-to-plastic) 13 were sensitive to one or two of the implanted metals. In a prospective series of 112 patients, nine were sensitive to nickel before and another three developed sensitivity to nickel or cobalt after the arthroplasty. In the retrospective as well as in the prospective series the complications could in all cases but one be explained on grounds other than allergy. The incidence of contact allergy to nickel before a planned arthroplasty was 12 per cent in females and 4 per cent in males. It is doubtful whether metal sensitivity could be induced by a total hip arthroplasty. However, in cases of a preexisting metal allergy, a certain degree of caution is recommended.