PMMA Cement Allergy Misleading Total Knee Arthroplasty Infection.

Arthroscopic and prosthetic hip and knee joint infection are uncommon; however, devastating complications in adult reconstruction surgery. An acute onset of pain combined with effusion, erythema, warmth and fever are the typical signs of early infection. Hypersensitivity or allergic reactions to arthroplasty components, concerning mainly metal-to-metal bearings and metal-on-plastic total knee arthroplasties have also been reported. Inflammation associated with allergic reaction to any of these materials (metallic and/or acrylic bone cement) can plausibly cause a number of similar manifestations to infection such as loosening, instability, stiffness, arthrofibrosis, swelling, warmth, and pain. This article presents a patient without known polymethylmethacrylate (PMMA) bone cement allergy who experienced a prosthetic joint infection after a cemented total knee arthroplasty. The diagnosis of infection was misled by the wrong timing of cultures with respect to antibiotics cessation, and the documentation of PMMA cement allergy with allergiologic examination and patch testing.