The assessment of disability associated with osteoarthritis.
OBJECTIVE
Disability (activity limitation) is an important and common health outcome for patients with osteoarthritis, making accurate measures essential. This paper explores self-report measures of activity limitation associated with osteoarthritis and reports on recent conceptual advances that impact on the measurement of activity limitation.


RESULTS
The Western Ontario and McMaster Universities Osteoarthritis Index and the Short Form-36, the most commonly used measures to assess activity limitation, continue to be validated in osteoarthritis. There has been little consensus, however, about which measure to use across different types of osteoarthritis. While new measures have been developed to assess activity limitation, it remains unclear whether or not these are an improvement over existing measures. The International Classification of Functioning, Disability and Health is becoming an important consideration. Commonly used measures do not map directly onto individual constructs of this classification, however a new measure for Japanese people with knee osteoarthritis was developed based on these constructs.


CONCLUSIONS
There have been significant developments in the conceptual approach to measuring activity limitation. Measures are needed that operationalize activity limitation as defined by the International Classification of Functioning, Disability and Health (within or ideally across cultures), providing a common underlying construct for measures and hence facilitating comparability across studies.
Pollard
Beth
B
School of Psychology, University of Aberdeen, William Guild Building, Aberdeen, UK. beth.pollard@abdn.ac.uk
Johnston
Marie
M
D004185:Disability Evaluation; D006801:Humans; D007564:Japan; D009864:Ontario; D020370:Osteoarthritis, Knee / Q000208:ethnology; D018434:Sickness Impact Profile