title: Risk factors for periprosthetic joint infection in total knee arthroplasty.
abstract: OBJECTIVE
  To evaluate the incidence and risk factors of periprosthetic joint infection (PJI) in patients undergoing total knee arthroplasty (TKA) in a high-volume hospital.
  
  
  METHODS
  Records of 1133 primary TKAs were reviewed. Correlation between surgery volume and infection rate was determined. Risk factors for PJI were identified using case-control analysis of variables. TKAs performed between October 2012 and March 2013 without infection were used as controls.
  
  
  RESULTS
  Of 1133 TKAs, 8 (0.71%) PJI occurred. The organisms involved were Staphylococcus aureus (n=4), coagulase-negative staphylococci (n=2), Pseudomonas aeruginosa (n=1), and methicillin-resistant S aureus (n=1). In the 6-month period chosen as the control period, one (0.52%) out of 192 TKAs developed PJI. Hospital annual volume did not correlate with infection rate (p=0.766). Significant risk factors included young age, comorbidities such as diabetes, anaemia, thyroid disease, heart disease, lung disease, and long operating time. Six of the 8 patients with PJIs had at least one risk factor. However, the number of patients with infection was too small to have sufficient power.
  
  
  CONCLUSIONS
  Comorbidities are a risk factor for PJI. Perioperative optimisation of comorbidities and the use of antibiotic-loaded cement in patients with severe comorbidities should be considered.
authors.affiliation: Total Joint Replacement Center, Yan Chai Hospital, Hong Kong.
authors.forename: Qunn Jid
authors.initials: QJ
authors.lastname: Lee
authors.forename: Wai Ping
authors.initials: WP
authors.lastname: Mak
authors.forename: Yiu Chung
authors.initials: YC
authors.lastname: Wong
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001170:Arthritis, Infectious / Q000209:etiology*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000706:statistics & numerical data; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D007720:Knee Prosthesis / Q000009:adverse effects*; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus; D008875:Middle Aged; D016459:Prosthesis-Related Infections / Q000209:etiology*; D011550:Pseudomonas aeruginosa; D012189:Retrospective Studies; D012307:Risk Factors; D013203:Staphylococcal Infections
chemical_list: D000900:Anti-Bacterial Agents
keywords: arthroplasty, replacement, knee; comorbidity; hospitals, high-volume; infection