title: Previous fracture surgery is a major risk factor of infection after total knee arthroplasty.
abstract: OBJECTIVE
  Total knee arthroplasty (TKA) has been proven to be the most effective treatment for patients with severe joint disease. Although infection is not a frequent complication, it is certainly one of the most dreaded. The purpose of this study was to identify factors associated with infection after TKA.
  
  
  METHODS
  Between 1995 and 2006, 2,022 primary TKAs in 1,146 patients were evaluated. Flexible Nichidai Knee (FNK) was used as a prothesis in all subjects. Twenty-four patient-specific data items were collected via chart review for each patient. Revision arthroplasty procedures and infected knees were excluded. The medical records were reviewed to extract the following information: age, gender, body mass index (BMI), preoperative C-reactive protein (CRP), preoperative erythrocyte sedimentation rate (ESR), preoperative total protein (TP), duration of surgery, operative blood loss, total blood loss, duration of surgical drain, duration of antibiotic prophylaxis, primary diagnoses, smoking, diabetes mellitus, steroid or disease modifying anti-rheumatic drugs (DMARDs) therapy, previous operation around the knee joint, previous arthroscopic surgery, previous non-arthroscopic surgery, previous high tibial osteotomy (HTO) or open reduction internal fixation (ORIF), remnants of previous internal fixation material, bone graft, patella replacement, and bone cement.
  
  
  RESULTS
  The median age of the patients at the time of primary TKA was 72 (range, 26-91) years. The median follow-up period after primary TKA was 42 (range, 6-145) months. During the study period, 17 infected knee arthroplasties in 17 patients were identified. Previous history of ORIF, male gender, remnants of previous internal fixation material, and BMI showed significant correlation with postoperative infection.
  
  
  CONCLUSIONS
  This study identified previous history of fracture and remnants of internal fixation as major risk factors of infection after TKA. For clinical relevance, surgeons should be aware of potential infection when performing TKA in patients with these risk factors and patients should be informed of the potential risks.
authors.affiliation: Department of Orthopaedic Surgery, Nihon University School of Medicine, 30-1, Ohyaguchikamimachi, Itabashi-ku, Tokyo, 173-8610, Japan. gegegen1978@yahoo.co.jp
authors.forename: Gen
authors.initials: G
authors.lastname: Suzuki
authors.forename: Shu
authors.initials: S
authors.lastname: Saito
authors.forename: Takao
authors.initials: T
authors.lastname: Ishii
authors.forename: Sayaka
authors.initials: S
authors.lastname: Motojima
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Tokuhashi
authors.forename: Junnosuke
authors.initials: J
authors.lastname: Ryu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000601:surgery*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D015992:Body Mass Index; D016009:Chi-Square Distribution; D005260:Female; D050723:Fractures, Bone / Q000150:complications*; D006801:Humans; D007720:Knee Prosthesis; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D011474:Prosthesis Design; D016459:Prosthesis-Related Infections / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors