Determinants of self-report outcome measures in people with knee osteoarthritis

Arch Phys Med Rehabil. 2006 Jan;87(1):96-104. doi: 10.1016/j.apmr.2005.08.110.


Objectives: To identify the determinants of self-report mobility measures in people with knee osteoarthritis (OA) and to compare self-report measures with physical performance.

Design: Cross-sectional, prospective.

Setting: Motor performance laboratory and human mobility research center.

Participants: A convenient sample of 54 participants with medial compartment knee OA (32 women, 22 men; age 68.3+/-8.7y; range, 50-87y). Three participants were excluded because of the presence of lateral knee OA on radiographs.

Interventions: Not applicable.

Main outcome measures: Self-reports were recorded by using the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). Performance measures included the six-minute walk test (6MWT), Timed Up & Go (TUG) test, and a standardized stair-climbing task (STR).

Results: Stepwise linear regression analysis identified models that included pain, quadriceps and hamstrings strength, and depression to explain 62% to 73% of the variance in scores on the physical functioning subscale of the WOMAC and the SF-36. These self-report measures had a moderate relation (r range, .46-.64) with performance measures (6MWT, TUG, STR).

Conclusions: Self-report measures were strongly related to pain; physical performance measures were strongly related to self-efficacy. Regression models showed that self-report scores reflect pain, knee strength, and depression. The relation between self-report and performance measures was moderate, suggesting that these examine different aspects of mobility.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activities of Daily Living*
  • Aged
  • Aged, 80 and over
  • Cross-Sectional Studies
  • Disability Evaluation
  • Female
  • Humans
  • Linear Models
  • Male
  • Middle Aged
  • Osteoarthritis, Knee / diagnosis*
  • Osteoarthritis, Knee / rehabilitation*
  • Pain Measurement
  • Patient Participation
  • Probability
  • Prospective Studies
  • Quality of Life*
  • Range of Motion, Articular / physiology*
  • Self Concept
  • Sensitivity and Specificity
  • Severity of Illness Index
  • Sickness Impact Profile