title: Preoperative predictors of returning to work following primary total knee arthroplasty.
abstract: BACKGROUND
  There is little in the literature to guide clinicians in advising patients regarding their return to work following a primary total knee arthroplasty. In this study, we aimed to identify which factors are important in estimating a patient's time to return to work following primary total knee arthroplasty, how long patients can anticipate being off from work, and the types of jobs to which patients are able to return following primary total knee arthroplasty.
  
  
  METHODS
  A prospective cohort study was performed in which patients scheduled for a primary total knee arthroplasty completed a validated questionnaire preoperatively and at four to six weeks, three months, and six months postoperatively. The questionnaire assessed the patient's occupational physical demands, ability to perform job responsibilities, physical status, and motivation to return to work as well as factors that may impact his or her recovery and other workplace characteristics. Two survival analysis models were constructed to evaluate the time to return to work either at least part-time or full-time. Acceleration factors were calculated to indicate the relative percentage of time until the patient returned to work.
  
  
  RESULTS
  The median time to return to work was 8.9 weeks. Patients who reported a sense of urgency about returning to work were found to return in half the time taken by other employees (acceleration factor = 0.468; p < 0.001). Other preoperative factors associated with a faster return to work included being female (acceleration factor = 0.783), self-employment (acceleration factor = 0.792), higher mental health scores (acceleration factor = 0.891), higher physical function scores (acceleration factor = 0.809), higher Functional Comorbidity Index scores (acceleration factor = 0.914), and a handicap accessible workplace (acceleration factor = 0.736). A slower return to work was associated with having less pain preoperatively (acceleration factor = 1.132), having a more physically demanding job (acceleration factor = 1.116), and receiving Workers' Compensation (acceleration factor = 4.360).
  
  
  CONCLUSIONS
  Although the physical demands of a patient's job have a moderate influence on the patient's ability to return to work following a primary total knee arthroplasty, the patient's characteristics, particularly motivation, play a more important role.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4945, USA. jxs178@case.edu
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Styron
authors.forename: Wael K
authors.initials: WK
authors.lastname: Barsoum
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Smyth
authors.forename: Mendel E
authors.initials: ME
authors.lastname: Singer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000534:rehabilitation*; D004651:Employment / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009042:Motivation; D009790:Occupations; D010147:Pain Measurement; D011446:Prospective Studies; D020127:Recovery of Function; D011795:Surveys and Questionnaires; D016019:Survival Analysis; D013997:Time Factors; D014938:Work Capacity Evaluation