Relationship between self-reported and performance-based tests in a hip and knee joint replacement population

Clin Rheumatol. 2009 Mar;28(3):253-7. doi: 10.1007/s10067-008-1021-y. Epub 2008 Oct 8.


Our objectives were: (1) to assess the relationship between self-reported measures (Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and Medical Outcomes Study Short Form-36 (SF-36)) and a performance-based timed-up-and-go (TUG) test in a hip and knee joint replacement population and (2) to determine the predictors of postoperative functional status as measured by the 12-week WOMAC and TUG scores. We surveyed 200 patients undergoing primary hip or knee replacement surgery for demographic data and outcome scores at baseline and 12-week follow-up. There was a weak correlation between preoperative TUG scores and preoperative SF-36 physical function scores (r = -0.28, p < 0.0001), SF-36 role-physical scores (r = -0.21, p = 0.0022) and WOMAC (r = 0.29, p < 0.0001) scores. The relationship was stronger between the postoperative TUG scores and WOMAC scores (r = 0.43, p < 0.0001), SF-36 physical function scores (r = -0.39, p < 0.0001) and SF-36 role-physical (r = -0.33, p < 0.0001) scores. Significant predictors for the TUG test at 12-week follow-up were age (p = 0.004) and preoperative TUG scores (p < 0.0001). Given low-to-moderate relationship between self-reported and performance-based tools, both tests are needed to assess the true level of patient disability.

MeSH terms

  • Activities of Daily Living / classification*
  • Aged
  • Arthroplasty, Replacement, Hip*
  • Arthroplasty, Replacement, Knee*
  • Disability Evaluation*
  • Female
  • Health Status
  • Humans
  • Male
  • Osteoarthritis, Hip / physiopathology
  • Osteoarthritis, Hip / surgery*
  • Osteoarthritis, Knee / physiopathology
  • Osteoarthritis, Knee / surgery*
  • Pain Measurement
  • Personal Satisfaction
  • Range of Motion, Articular
  • Retrospective Studies
  • Self-Examination / methods*
  • Severity of Illness Index