title: A cost-utility analysis comparing the cost-effectiveness of simultaneous and staged bilateral total knee arthroplasty.
abstract: BACKGROUND
  The safety and efficacy of simultaneous or staged bilateral total knee arthroplasty have long been debated among orthopaedic surgeons. Advocates for simultaneous bilateral total knee arthroplasty posit that the benefits of decreased costs and recovery time, with no difference in functional outcomes, outweigh the economic costs of potential complications. The purpose of the study was to conduct a cost-utility analysis comparing simultaneous bilateral total knee arthroplasty with staged bilateral total knee arthroplasty.
  
  
  METHODS
  A Markov model was designed to compare the cost-effectiveness of simultaneous bilateral total knee arthroplasty with that of staged bilateral total knee arthroplasty. Nationwide Inpatient Sample data sets from 2004 to 2007 were used to identify 24,574 simultaneous and 382,496 unilateral procedures. On the basis of the codes of the International Classification of Diseases, Ninth Revision, Clinical Modification, perioperative complications were categorized as minor, major, and mortality, and respective probability values were calculated. Nationwide Inpatient Sample data were used to determine hospital costs conditional on procedure type and complications. Rehabilitation costs, anesthesia costs, and heath utilities were estimated from the literature. To minimize selection bias, propensity score matching was used to match the groups on comorbid conditions, socioeconomic variables, and hospital characteristics.
  
  
  RESULTS
  Using the matched sample, all complication rates were higher for the staged group. The estimated mean cost (in 2012 U.S. dollars) was $43,401 for simultaneous bilateral total knee arthroplasty compared with $72,233 for staged bilateral total knee arthroplasty. The quality-adjusted life years gained were 9.31 for simultaneous bilateral total knee arthroplasty and 9.29 for staged bilateral total knee arthroplasty. On the basis of these matched results, simultaneous bilateral total knee arthroplasty dominated staged bilateral total knee arthroplasty with lower costs and better outcomes.
  
  
  CONCLUSIONS
  On the basis of this analysis, simultaneous bilateral total knee arthroplasty is more cost-effective than staged bilateral total knee arthroplasty, with lower costs and better outcomes for the average patient. These data can inform shared medical decision-making when bilateral total knee arthroplasty is indicated.
authors: University of North Carolina at Charlotte and OrthoCarolina Research Institute, Charlotte, North Carolina, USA. Susan.Odum@orthocarolina.com
authors: Susan M
authors: SM
authors: Odum
authors: Jennifer L
authors: JL
authors: Troyer
authors: Michael P
authors: MP
authors: Kelly
authors: Russell D
authors: RD
authors: Dedini
authors: Kevin J
authors: KJ
authors: Bozic
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000191:economics* / Q000379:methods; D003362:Cost-Benefit Analysis; D006801:Humans; D018803:Models, Economic; D011183:Postoperative Complications / Q000191:economics* / Q000209:etiology; D019057:Quality-Adjusted Life Years; D016896:Treatment Outcome