title: Safety of simultaneous bilateral total knee arthroplasty. A meta-analysis.
abstract: BACKGROUND
  The safety of simultaneous bilateral total knee replacement remains controversial. Some studies have demonstrated a higher rate of serious complications, including death, following bilateral procedures, whereas others have suggested no increase in the complication rate. The objective of this meta-analysis was to compare the safety of simultaneous bilateral total knee replacement with that of staged bilateral and unilateral total knee replacements.
  
  
  METHODS
  A computerized literature search was conducted to identify all citations, from 1966 to 2005, concerning bilateral total knee replacement. All of the English-language abstracts were obtained. A multistage assessment was then performed to identify articles fulfilling the inclusion criteria for the study. All randomized, prospective studies reporting the outcome of bilateral total knee replacement were included. The details of the reported data were extracted, and an extensive analysis of relevant variables was carried out.
  
  
  RESULTS
  One hundred and fifty published articles were identified, and eighteen that included a total of 27,807 patients (44,684 knees) were included in the meta-analysis. There were 10,930 unilateral total knee replacements, 16,419 simultaneous bilateral total knee replacements, and 458 staged bilateral total knee replacements with at least three months between the operative procedures. The prevalences of pulmonary embolism (odds ratio = 1.8), cardiac complications (odds ratio = 2.49), and mortality (odds ratio = 2.2) were higher after simultaneous bilateral total knee replacement. The prevalence of deep venous thrombosis was lower after simultaneous bilateral total knee replacement, but this difference was not significant. The complication rates after the staged bilateral total knee replacements were similar to those in the patients who had undergone unilateral total knee replacement only.
  
  
  CONCLUSIONS
  Compared with staged bilateral or unilateral total knee replacement, simultaneous bilateral total knee replacement carries a higher risk of serious cardiac complications, pulmonary complications, and mortality. The period of time between staged procedures that would eliminate these increased risks could not be determined from this study.
  
  
  METHODS
  Therapeutic Level III.
authors.affiliation: Department of Orthopedic Surgery, Rothman Institute at Thomas Jefferson University Hospital, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Camilo
authors.initials: C
authors.lastname: Restrepo
authors.forename: Javad
authors.initials: J
authors.lastname: Parvizi
authors.forename: Thomas
authors.initials: T
authors.lastname: Dietrich
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Einhorn
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods*; D019320:Embolism, Paradoxical / Q000453:epidemiology; D006331:Heart Diseases / Q000453:epidemiology; D006801:Humans; D016017:Odds Ratio; D011183:Postoperative Complications / Q000453:epidemiology; D016032:Randomized Controlled Trials as Topic; D020246:Venous Thrombosis / Q000453:epidemiology