The development of metal hypersensitivity in patients with metal-to-plastic hip arthroplasties.

Sixty-six patients who had to undergo total hip replacement by means of a metal-to-plastic Stanmore prosthesis, were patch-tested prior to and 6 to 12 months after surgery with the standard ICDRG all allergens series and with acrylic monomer 5% in acetone. In 62 patients the history of metal allergy as well as the patch tests to all tested allergens were negative. One patient with a history of metal allergy reacted negatively before surgery; about 6 months after surgery the patch test to nickel sulphate was positive (2 plus). Three other patients developed positive patch test reaction after surgery: two reacted positively to nickel sulphate (2 plus) and one to cobalt chloride (2 plus). In none of the 66 patients have local side effects of the prostheses been found to date.