title: Incidence of delirium following total joint replacement in older adults: a meta-analysis.
abstract: OBJECTIVE
  Delirium is common in older adults following total joint replacement (TJR) of the hip and knee. However, reports of the incidence of delirium vary widely, limiting their usefulness. The current meta-analysis therefore examined (1) the incidence of delirium in older patients who underwent TJR and (2) whether these rates vary according to the (a) joint (hip/knee replacement), (b) inclusion/exclusion of patients who underwent simultaneous bilateral surgery, (c) inclusion/exclusion of patients with preexisting cognitive impairments, (d) type of anesthesia (regional/general), (e) method/frequency of assessment, and (f) postoperative interval.
  
  
  METHODS
  Data from 24 studies (2,895 patients) that measured postsurgical delirium following TJR were analyzed. Mean weighted proportions were calculated using a random-effects model to assess the overall incidence of delirium and whether the rate varied according to the aforementioned variables.
  
  
  RESULTS
  Overall, 17% of patients who underwent TJR developed delirium during hospital admission. Individual estimates varied from 0% to 82%, but this variability was not adequately explained by the variables that were examined.
  
  
  CONCLUSIONS
  Delirium is relatively common following TJR; however, it remains unclear why individual estimates vary so widely. Health professionals working with these patients should remain alert to the presentation, diagnosis and management of delirium to optimize postsurgical outcomes.
authors.affiliation: School of Psychology, University of Adelaide, South Australia, Australia 5005. Electronic address: julia.scott@adelaide.edu.au.
authors.forename: J E
authors.initials: JE
authors.lastname: Scott
authors.affiliation: School of Psychology, University of Adelaide, South Australia, Australia 5005. Electronic address: jane.mathias@adelaide.edu.au.
authors.forename: J L
authors.initials: JL
authors.lastname: Mathias
authors.affiliation: Department of Clinical Psychology, Flinders Medical Centre, South Australia, Australia 5042; School of Psychology, University of Adelaide, South Australia, Australia 5005. Electronic address: tony.kneebone@flinders.edu.au.
authors.forename: A C
authors.initials: AC
authors.lastname: Kneebone
mesh_terms: D000368:Aged; D019643:Arthroplasty, Replacement / Q000009:adverse effects / Q000706:statistics & numerical data*; D003693:Delirium / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D011183:Postoperative Complications / Q000453:epidemiology*
keywords: Delirium; Elderly; Incidence; Meta-analysis; Total joint replacement