title: Seronegative infections in hip and knee arthroplasty: periprosthetic infections with normal erythrocyte sedimentation rate and C-reactive protein level.
abstract: The aim of our study was to describe the characteristics, treatment, and outcomes of patients with periprosthetic joint infection (PJI) and normal inflammatory markers after total knee arthroplasty (TKA) and total hip arthroplasty (THA). In total 538 TKAs and 414 THAs underwent surgical treatment for PJI and met the inclusion criteria. Pre-operative erythrocyte sedimentation rate (ESR) and C-reactive protein level (CRP) were reviewed to identify the seronegative cohort. An age- and gender-matched cohort was identified from the remaining patients for comparison. Overall, 4% of confirmed infections were seronegative (21 TKA and 17 THA). Of those who underwent pre-operative aspiration, cultures were positive in 76% of TKAs (n = 13) and 64% of THAs (n = 7). Cell count and differential were suggestive of infection in 85% of TKA (n = 11) and all THA aspirates (n = 5). The most common organism was coagulase-negative Staphylococcus. Seronegative infections were associated with a lower aspirate cell count and a lower incidence of Staphylococcus aureus infection. Two-stage revision was performed in 35 cases (95%). At a mean of five years (14 to 162 months) following revision, re-operation for infection occurred in two TKAs, and one THA. From our study we estimate around 4% of patients with PJI may present with normal ESR and CRP. When performed, pre-operative aspirate is useful in delivering a definitive diagnosis. When treated, similar outcomes can be obtained compared with patients with positive serology.
authors.affiliation: Washington Orthopedics and Sports Medicine, 5215 Loughboro Road NW, Suite 200, Washington, D.C. 20016, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: McArthur
authors.affiliation: Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Abdel
authors.affiliation: Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Taunton
authors.affiliation: Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA.
authors.forename: D R
authors.initials: DR
authors.lastname: Osmon
authors.affiliation: Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA.
authors.forename: A D
authors.initials: AD
authors.lastname: Hanssen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip; D019645:Arthroplasty, Replacement, Knee; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000032:analysis*; D005188:False Negative Reactions; D005260:Female; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D007720:Knee Prosthesis / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D016459:Prosthesis-Related Infections / Q000097:blood* / Q000175:diagnosis / Q000628:therapy; D012189:Retrospective Studies; D012698:Serologic Tests
chemical_list: D002097:C-Reactive Protein
keywords: Periprosthetic infection; Serology; Total hip arthroplasty; Total knee arthroplasty