title: Identification of risk factors for urinary retention following total knee arthroplasty: a Singapore hospital experience.
abstract: BACKGROUND
  Urinary retention is associated with an increased rate of urinary tract infections and deep sepsis following total joint arthroplasty. This study was carried out to investigate the incidence of urinary retention following total knee arthroplasty in a Singapore hospital, and to identify risk factors associated with the development of this complication in our patient population.
  
  
  METHODS
  The charts of 125 consecutive patients who underwent primary total knee arthroplasty between January and December 2004 were reviewed. The incidence of postoperative urinary retention was correlated with the following factors: age, gender, choice of anaesthesia, duration of surgery, and analgesic technique. Statistical analysis was performed with univariate and multivariate logistic regression models. There were 109 female and 16 male patients. The mean age of the patients was 67.5 years (range, 50-86 years).
  
  
  RESULTS
  Ten patients developed urinary retention, giving an overall rate of 8.0 percent (95 percent confidence interval [CI], 3.9-4.2). Male gender (odds-ratio [OR] is 5.9; 95 percent CI, 1.2-29.5; p-value is 0.03) and epidural analgesia (OR is 7.6; 95 percent CI, 1.7-35.0; p-value is 0.009) were found to be the only factors significantly associated with postoperative urinary retention. Patient age, duration of surgery and choice of anaesthesia were not found to be significantly associated with urinary retention.
  
  
  CONCLUSIONS
  In our patient population, male patients and patients receiving epidural postoperative analgesia are at increased risk of developing urinary retention following total knee arthroplasty.
authors.affiliation: Department of Orthopaedic Surgery, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074. lingaraj_krishna@yahoo.com.sg
authors.forename: K
authors.initials: K
authors.lastname: Lingaraj
authors.forename: M
authors.initials: M
authors.lastname: Ruben
authors.forename: Y H
authors.initials: YH
authors.lastname: Chan
authors.forename: S De
authors.initials: SD
authors.lastname: Das
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015360:Analgesia, Epidural; D000768:Anesthesia, General; D000775:Anesthesia, Spinal; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D012846:Singapore / Q000453:epidemiology; D016055:Urinary Retention / Q000453:epidemiology*