title: Psychosocial determinants of outcomes in knee replacement.
abstract: OBJECTIVE
  To identify potential psychosocial and educational barriers to clinical success following knee replacement.
  
  
  METHODS
  The authors evaluated 241 patients undergoing total knee replacement, preoperatively and 6 months after surgery. Outcomes included the Western Ontario McMaster (WOMAC) scale and the Knee Society rating system (KSRS). Independent variables included: the medical outcome study-social support scale; depression, anxiety and stress scale; brief COPE inventory; health locus of control; arthritis self-efficacy scale and the life orientation test-revised. Multiple regression models evaluated associations of baseline demographic and psychosocial variables with outcomes at 6 months, controlling for body mass index, comorbidities and baseline outcome scores.
  
  
  RESULTS
  Patients' mean age was 65 ± 9 years; 65% were women. Most patients improved outcomes after surgery. Several psychosocial variables were associated with outcomes. Regression analyses indicated lower education, less tangible support, depression, less problem-solving coping, more dysfunctional coping, lower internal locus of control were associated with worse WOMAC scores (R(2) contribution of psychosocial variables for pain 0.07; for function, 0.14). Older age, lower education, depression and less problem-solving coping were associated with poorer total KSRS scores (R(2) contribution of psychosocial variables to total KSRS model 0.09). Psychosocial variables as a set contributed from 25% to 74% of total explained variance across the models tested.
  
  
  CONCLUSIONS
  Patients' level of education, tangible support, depression, problem-solving coping, dysfunctional coping and internal locus of control were associated with pain and functional outcomes after knee replacement. The findings suggest that, in addition to medical management, perioperative psychosocial evaluation and intervention are crucial in enhancing knee replacement outcomes.
authors.affiliation: The University of Texas, MD Anderson Cancer Center, Houston, Texas 77030, USA
authors.forename: Maria A
authors.initials: MA
authors.lastname: Lopez-Olivo
authors.forename: Glenn C
authors.initials: GC
authors.lastname: Landon
authors.forename: Sherwin J
authors.initials: SJ
authors.lastname: Siff
authors.forename: David
authors.initials: D
authors.lastname: Edelstein
authors.forename: Chong
authors.initials: C
authors.lastname: Pak
authors.forename: Michael A
authors.initials: MA
authors.lastname: Kallen
authors.forename: Melinda
authors.initials: M
authors.lastname: Stanley
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Kausha C
authors.initials: KC
authors.lastname: Robinson
authors.forename: Maria E
authors.initials: ME
authors.lastname: Suarez-Almazor
mesh_terms: D000223:Adaptation, Psychological; D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000523:psychology* / Q000534:rehabilitation; D005260:Female; D006801:Humans; D007389:Internal-External Control; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000534:rehabilitation / Q000601:surgery*; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D020127:Recovery of Function; D012720:Severity of Illness Index; D012944:Social Support; D012959:Socioeconomic Factors; D016896:Treatment Outcome