title: Willingness to undergo surgery again validated clinically important differences in health-related quality of life after total hip replacement or total knee replacement surgery.
abstract: OBJECTIVE
  To determine clinically important differences (CIDs) in health-related quality of life (HRQoL) after total hip replacement (THR) or total knee replacement (TKR) surgery, using the Short Form 36 (SF-36).
  
  
  METHODS
  SF-36 scores were collected 2 weeks before and at 1.5-6 years after joint replacement in 586 THR and 400 TKR patients in a multicenter cohort study. We calculated distribution-based CIDs (0.8 standard deviations of the preoperative score) for each SF-36 subscale. Responders (patients with an improvement in HRQoL ≥ CID of a particular subscale) were compared with nonresponders using an external validation question: willingness to undergo surgery again.
  
  
  RESULTS
  CIDs for THR/TKR were physical functioning (PF), 17.9/16.7; role-physical (RP), 31.1/33.4; bodily pain (BP), 16.8/16.2; general health, 15.5/15.7; vitality, 17.3/16.7; social functioning (SF), 22.0/19.9; role-emotional, 33.7/33.6; and mental health, 14.8/14.1. CIDs of PF, RP, BP, and SF were validated by the validation question.
  
  
  CONCLUSIONS
  Valid and precise CIDs are estimated of PF, RP, BP, and SF, which are relevant in HRQoL subscales for THR and TKR patients. CIDs of all other subscales should be used cautiously.
authors.affiliation: Department of Orthopaedic Surgery, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands. Electronic address: j.c.keurentjes@lumc.nl.
authors.forename: J Christiaan
authors.initials: JC
authors.lastname: Keurentjes
authors.forename: Marta
authors.initials: M
authors.lastname: Fiocco
authors.forename: Rob G
authors.initials: RG
authors.lastname: Nelissen
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D005500:Follow-Up Studies; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain; D011788:Quality of Life; D012086:Reoperation / Q000523:psychology; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
keywords: Clinically important differences; Health-related quality of life; Short form 36; Total hip replacement; Total knee replacement