title: Analysis of factors affecting operating time, postoperative complications, and length of stay for total knee arthroplasty: nationwide web-based survey.
abstract: BACKGROUND
  This study aimed to clarify the impact of various factors on the operating time, postoperative complications, and length of stay (LOS) after total knee arthroplasty (TKA).
  
  
  METHODS
  We identified 3577 TKAs performed in 345 hospitals in Japan from November 2006 to March 2007. We examined the patient characteristics, surgical procedure details, hospital and surgeon volumes, and outcome variables (operating time, postoperative complications, LOS).
  
  
  RESULTS
  The average operating time was 127 +/- 47 min. The rate of postoperative complications was 9.8%. The average LOS was 35.1 +/- 15.9 days. In multivariate regression analyses, the average operating times were significantly shorter at hospitals with > or = 50 cases per year compared to hospitals with < 10 cases per year and for surgeons with > or =100 total cases compared to surgeons with < 100 total cases. A longer operating time was associated with revision surgery and use of computer navigation. Significant predictors of postoperative complications were age, body mass index, and cerebrovascular disease. Shorter LOS was associated with higher hospital volume and use of a clinical pathway, whereas age, cardiovascular disease, and revision surgery increased the length of stay.
  
  
  CONCLUSIONS
  Postoperative complications following TKA mainly depended on patient-based factors and were not significantly affected by the surgeon's experience.
authors.affiliation: Department of Health Management and Policy, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Yasunaga
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Matsuyama
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ohe
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D015992:Body Mass Index; D019091:Critical Pathways; D005260:Female; D006801:Humans; D020407:Internet; D007564:Japan; D007902:Length of Stay; D008297:Male; D009765:Obesity / Q000150:complications; D016017:Odds Ratio; D010043:Outcome and Process Assessment, Health Care; D011183:Postoperative Complications / Q000209:etiology; D012086:Reoperation; D012307:Risk Factors; D025321:Surgery, Computer-Assisted; D016526:Workload