Metal Hypersensitivity Mimicking Periprosthetic Erysipelas-Like Infection: A Case Report.

Metallic orthopaedic implants may release nickel (Ni), cobalt (Co), and chromium (Cr) into surrounding tissue through either corrosion or wear1. Correspondingly, elevated metal levels may be found in the blood and urine2,3. Despite high rates of cutaneous metal allergy in the general population (approximately 13% for Ni, 2% for Co, and 1% for Cr)4, allergy to metal implants is rare. Potential clinical presentations of metal-implant allergy include local or generalized eczema, impaired wound-healing, recurrent pain and effusions, and implant loosening5-7. Metal sensitivity rates have been found to be elevated in patients with failed arthroplasty8. Once periprosthetic joint infection (PJI) has been excluded in a symptomatic patient with a well-positioned implant following arthroplasty, the differential diagnosis should include metal hypersensitivity9. We report on a patient who developed an erythema suggestive of erysipelas on the right thigh after revision surgery with a cemented femoral implant (LINK, Hamburg, Germany). Because the C-reactive protein (CRP) level and blood-cell count were normal, infection was unlikely. To evaluate the possibility of an immune-mediated reaction, allergy testing, histopathological evaluation, and inflammatory mediator assessment were performed. The patient was informed that data concerning the case would be submitted for publication, and she provided consent. A fifty-seven-year-old woman with bilateral congenital hip dislocation underwent a fifth revision surgery on the right side, which included a long-stem femoral component with two additional distal wires to secure the implant (Fig. 1). Fixation of this long implant was performed with cement at the distal diaphysis and metaphysis. The femoral shaft was a cobalt, chromium, molybdenum (CoCrMo)-based alloy, and cerclages were made of stainless steel that contained Ni. Fig. 1 Anteroposterior radiograph taken after reconstruction with a cemented long-shaft component. Several weeks after surgery, itching and erythema overlying the …