Hypersensitivity to benzoyl peroxide in a cemented total knee arthroplasty: cement allergy.

A small but significant proportion of cemented total knee arthroplasties develop aseptic loosening. Polyethylene debris is unlikely to be the cause in the small subgroup that experiences early loosening. Allergy to polymethylmethacrylate bone cement or its constituents has been reported in several different industries and in dentistry, dermatology, and joint arthroplasty. Although allergy to polymethylmethacrylate bone cement or its constituents is unusual, the possibility of a systemic inflammatory response and consequent pain and loosening must be considered. We report a case history of a patient who developed a systemic reaction and intractable pain after a total knee arthroplasty who was subsequently shown to be hypersensitive to the benzoyl peroxide component of bone cement.