title: Epidemiology of septic arthritis of the knee at Hospital das Clínicas, Universidade de São Paulo.
abstract: BACKGROUND
  Septic arthritis is an infrequent disease although very important due to the possibility of disastrous outcomes if treatment is not adequately established. Adequate information concerning the epidemiology of septic arthritis is still lacking due to the uncommon nature of the disease as well as the struggle to establish a correct case-definition.
  
  
  OBJECTIVE
  To epidemiologically characterize the population seen at Hospital das Clínicas, University of São Paulo with a diagnosis of septic arthritis between 2006 and 2011.
  
  
  METHODS
  Sixty-one patients diagnosed with septic arthritis of the knee between 2006 and 2011 were retrospectively evaluated. The patients' clinical and epidemiological characteristics, the microorganisms that caused the infection and the patients' treatment and evolution were analyzed.
  
  
  RESULTS
  Septic arthritis of the knee was more common among men, with distribution across a variety of age ranges. Most diagnoses were made through positive synovial fluid cultures. The most prevalent clinical comorbidities were systemic arterial hypertension and diabetes mellitus, and the most commonly reported joint disease was osteoarthritis. Staphylococcus aureus was the prevailing pathogen. Fever was present in 36% of the cases. All patients presented elevation in inflammatory tests. Gram staining was positive in only 50.8% of the synovial fluid samples analyzed. Six patients presented complications and unfavorable evolution of their condition.
  
  
  CONCLUSIONS
  S. aureus is still the most common pathogen in acute knee infections in our environment. Gram staining, absence of fever and normal leukocyte count cannot be used to rule out septic arthritis.
authors.affiliation: Instituto de Ortopedia e Traumatologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (IOT-HCFMUSP), São Paulo, SP, Brazil. Electronic address: camilo_helito@yahoo.com.br.
authors.forename: Camilo Partezani
authors.initials: CP
authors.lastname: Helito
authors.affiliation: Instituto de Ortopedia e Traumatologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (IOT-HCFMUSP), São Paulo, SP, Brazil.
authors.forename: Guilherme Guelfi
authors.initials: GG
authors.lastname: Noffs
authors.affiliation: Instituto de Ortopedia e Traumatologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (IOT-HCFMUSP), São Paulo, SP, Brazil.
authors.forename: Jose Ricardo
authors.initials: JR
authors.lastname: Pecora
authors.affiliation: Instituto de Ortopedia e Traumatologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (IOT-HCFMUSP), São Paulo, SP, Brazil.
authors.forename: Riccardo Gomes
authors.initials: RG
authors.lastname: Gobbi
authors.affiliation: Instituto de Ortopedia e Traumatologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (IOT-HCFMUSP), São Paulo, SP, Brazil.
authors.forename: Luis Eduardo Passarelli
authors.initials: LE
authors.lastname: Tirico
authors.affiliation: Instituto de Ortopedia e Traumatologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (IOT-HCFMUSP), São Paulo, SP, Brazil.
authors.forename: Ana Lucia Munhoz
authors.initials: AL
authors.lastname: Lima
authors.affiliation: Instituto de Ortopedia e Traumatologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (IOT-HCFMUSP), São Paulo, SP, Brazil.
authors.forename: Priscila Rosalba
authors.initials: PR
authors.lastname: de Oliveira
authors.affiliation: Instituto de Ortopedia e Traumatologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (IOT-HCFMUSP), São Paulo, SP, Brazil.
authors.forename: Gilberto Luis
authors.initials: GL
authors.lastname: Camanho
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001170:Arthritis, Infectious / Q000453:epidemiology* / Q000382:microbiology; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007719:Knee Joint; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013582:Synovial Fluid / Q000382:microbiology; D055815:Young Adult
keywords: Epidemiology; Infection; Knee; Septic arthritis
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