title: Improvement following total knee replacement surgery: Exploring preoperative symptoms and change in preoperative symptoms.
abstract: OBJECTIVE
  To determine whether changes in preoperative osteoarthritis (OA) symptoms are associated with improvement after total knee replacement (TKR) and to identify predictors of clinically significant improvement.
  
  
  METHODS
  Data on Osteoarthritis Initiative participants who were annually assessed and underwent TKR were included. T0 was the assessment prior to TKR while T-1 was the assessment prior to that. T+2 was the second assessment after TKR. We compiled data on the Western Ontario and McMaster Universities OA Index (WOMAC), OA-related symptoms, and radiographic severity. We defined clinically significant improvement as improvement in WOMAC total score ≥ to the minimal important difference (MID) (0.5 SD of mean change) between T0 and T+2 and also considered other definitions of improvement. Logistic regression models were performed to evaluate the relationship between improvement and preoperative measures.
  
  
  RESULTS
  Improved (n = 211) compared to unimproved (n = 58) patients had greater worsening of their WOMAC pain (p = 0.002) and disability (p < 0.001) from T-1 to T0. Preoperative measures as predictors of improvement included higher WOMAC disability (OR = 1.08, p < 0.001), presence of chronic OA symptoms in the surgical knee (OR = 5.77, p = 0.033), absence of OA-related symptoms in the contralateral knee (OR = 9.25, p < 0.001), exposure to frequent knee bending (OR = 3.46, p = 0.040), and having a Kellgren-Lawrence x-ray grade of ≥2 in the contralateral knee (OR = 4.71, p = 0.010).
  
  
  CONCLUSIONS
  More than 75% of participants had improvement after TKR. Improved patients were more likely to have escalation of OA pain and disability prior to surgery than unimproved patients. Other preoperative measures predicted improvement after TKR.
authors.affiliation: Department of Medicine, University of Arizona Arthritis Center, University of Arizona, 1501 N Campbell Ave, PO Box 245093, Tucson, AZ 85724-5093. Electronic address: evina@email.arizona.edu.
authors.forename: Ernest R
authors.initials: ER
authors.lastname: Vina
authors.affiliation: Department of Medicine, University of Pittsburgh, Pittsburgh, PA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hannon
authors.affiliation: Department of Medicine, University of Arizona Arthritis Center, University of Arizona, 1501 N Campbell Ave, PO Box 245093, Tucson, AZ 85724-5093.
authors.forename: C Kent
authors.initials: CK
authors.lastname: Kwoh
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D018450:Disease Progression; D006304:Health Status; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery*; D011788:Quality of Life; D020127:Recovery of Function; D012720:Severity of Illness Index; D016896:Treatment Outcome
keywords: improvement; joint replacement surgery; knee; osteoarthritis; postoperative outcomes