title: Body mass and weight thresholds for increased prosthetic joint infection rates after primary total joint arthroplasty.
abstract: OBJECTIVE
  Obesity increases the risk of deep infection after total joint arthroplasty (TJA). Our objective was to determine whether there may be body mass index (BMI) and weight thresholds indicating a higher prosthetic joint infection rate.
  
  
  METHODS
  We included all 9,061 primary hip and knee arthroplasties (mean age 70 years, 61% women) performed between March 1996 and December 2013 where the patient had received intravenous cefuroxime (1.5 g) perioperatively. The main exposures of interest were BMI (5 categories: < 24.9, 25-29.9, 30-34.9, 35-39.9, and ≥ 40) and weight (5 categories: < 60, 60-79, 80-99, 100-119, and ≥ 120 kg). Numbers of TJAs according to BMI categories (lowest to highest) were as follows: 2,956, 3,350, 1,908, 633, and 214, respectively. The main outcome was prosthetic joint infection. The mean follow-up time was 6.5 years (0.5-18 years).
  
  
  RESULTS
  111 prosthetic joint infections were observed: 68 postoperative, 16 hematogenous, and 27 of undetermined cause. Incidence rates were similar in the first 3 BMI categories (< 35), but they were twice as high with BMI 35-39.9 (adjusted HR = 2.1, 95% CI: 1.1-4.3) and 4 times higher with BMI ≥ 40 (adjusted HR = 4.2, 95% CI: 1.8-9.7). Weight ≥ 100 kg was identified as threshold for a significant increase in infection from the early postoperative period onward (adjusted HR = 2.1, 95% CI: 1.3-3.6).
  
  
  CONCLUSIONS
  BMI ≥ 35 or weight ≥ 100 kg may serve as a cutoff for higher perioperative dosage of antibiotics.
authors.affiliation: a Division of Orthopedics and Trauma Surgery , Geneva University Hospitals and Faculty of Medicine, University of Geneva , Geneva , Switzerland .
authors.forename: Anne
authors.initials: A
authors.lastname: Lübbeke
authors.affiliation: a Division of Orthopedics and Trauma Surgery , Geneva University Hospitals and Faculty of Medicine, University of Geneva , Geneva , Switzerland .
authors.forename: Matthieu
authors.initials: M
authors.lastname: Zingg
authors.affiliation: b Division of Infectious Diseases , Geneva University Hospitals and Faculty of Medicine, University of Geneva , Geneva , Switzerland .
authors.forename: Diemlan
authors.initials: D
authors.lastname: Vu
authors.affiliation: a Division of Orthopedics and Trauma Surgery , Geneva University Hospitals and Faculty of Medicine, University of Geneva , Geneva , Switzerland .
authors.forename: Hermes H
authors.initials: HH
authors.lastname: Miozzari
authors.affiliation: a Division of Orthopedics and Trauma Surgery , Geneva University Hospitals and Faculty of Medicine, University of Geneva , Geneva , Switzerland .
authors.forename: Panayiotis
authors.initials: P
authors.lastname: Christofilopoulos
authors.affiliation: a Division of Orthopedics and Trauma Surgery , Geneva University Hospitals and Faculty of Medicine, University of Geneva , Geneva , Switzerland .|b Division of Infectious Diseases , Geneva University Hospitals and Faculty of Medicine, University of Geneva , Geneva , Switzerland .
authors.forename: Ilker
authors.initials: I
authors.lastname: Uçkay
authors.affiliation: c Infection Control Program , Geneva University Hospitals and Faculty of Medicine, University of Geneva , Geneva , Switzerland.
authors.forename: Stephan
authors.initials: S
authors.lastname: Harbarth
authors.affiliation: a Division of Orthopedics and Trauma Surgery , Geneva University Hospitals and Faculty of Medicine, University of Geneva , Geneva , Switzerland .
authors.forename: Pierre
authors.initials: P
authors.lastname: Hoffmeyer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D019072:Antibiotic Prophylaxis; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology*; D002444:Cefuroxime / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016459:Prosthesis-Related Infections / Q000453:epidemiology* / Q000209:etiology; D012307:Risk Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D002444:Cefuroxime