title: Bilateral total knee arthroplasty: risk factors for major morbidity and mortality.
abstract: BACKGROUND
  Bilateral total knee arthroplasty (BTKA) performed during the same hospitalization carries increased risk for morbidity and mortality compared with the unilateral approach. However, no evidence-based stratifications to identify patients at risk for major morbidity and mortality are available. Our objective was to determine the incidence and patient-related risk factors for major morbidity and mortality among patients undergoing BTKA.
  
  
  METHODS
  Nationwide Inpatient Survey data collected for the years 1998 to 2007 were analyzed and cases of elective BTKA procedures were included. Patient demographics, including comorbidities, were analyzed and frequencies of mortality and major complications were computed. Subsequently, a multivariate analysis was conducted to determine independent risk factors for major morbidity and mortality.
  
  
  RESULTS
  Included were 42,003 database entries, representing an estimated 206,573 elective BTKAs. The incidence of major in-hospital complications and mortality was 9.5%. Risk factors for adverse outcome included advanced age (odds ratios [ORs] for age groups 65-74 and >75 years were 1.88 [confidence interval, CI: 1.72, 2.05] and 2.66 [CI: 2.42, 2.92], respectively, compared with the 45-65 years group), male gender (OR: 1.54 [CI: 1.44, 1.66]), and a number of comorbidities. The presence of congestive heart failure (OR: 5.55 [CI: 4.81, 6.39]) and pulmonary hypertension (OR: 4.10 [CI: 2.72, 6.10]) were the most significant risk factors associated with increased odds for adverse outcome.
  
  
  CONCLUSIONS
  We identified patient-related risk factors for major morbidity and mortality in patients undergoing BTKA. Our data can be used to aid in the selection of patients for this procedure.
authors.affiliation: Department of Anesthesiology, Hospital for Special Surgery, Weill Cornell Medical College, New York, NY, USA. memtsoudiss@hss.edu
authors.forename: Stavros G
authors.initials: SG
authors.lastname: Memtsoudis
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.forename: Ya-Lin
authors.initials: YL
authors.lastname: Chiu
authors.forename: Lazaros
authors.initials: L
authors.lastname: Poultsides
authors.forename: Alejandro
authors.initials: A
authors.lastname: Gonzalez Della Valle
authors.forename: Madhu
authors.initials: M
authors.lastname: Mazumdar
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000401:mortality*; D015897:Comorbidity; D017558:Elective Surgical Procedures; D005260:Female; D006333:Heart Failure / Q000401:mortality; D006801:Humans; D006976:Hypertension, Pulmonary / Q000401:mortality; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D018579:Patient Selection; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology