Knee outcome survey
Original Editor - William Jones
The Knee Outcome Survey (KOS) is a patient-completed questionnaire that provides a percentage of disability during every day activities (activities of daily living subscale) or sports (sports activity subscale). The lower the percentage, the higher the disability.
Method of Use
This is a self-report measure that is broken down into two categories (ADLs and sport activities) that rates perceived disability with 5 being "no difficulty" and 0 being "unable to perform".
The test-retest reliability coefficient (intraclass correlation coefficient[2,1]) was 0.97. These results suggest that the Activities of Daily Living Scale is a reliable, valid, and responsive instrument for the assessment of functional limitations that result from a wide variety of pathological disorders and impairments of the knee.
Validity has been demonstrated by moderately strong correlations with concurrent measures of function, including the Lysholm Knee Scale (r = 0.78 to 0.86) and the global assessment of function as measured on a scale ranging from 0 to 100 points (r = 0.66 to 0.75).
Standardized effect size of the Activity of Daily Living Scale was 0.63, Guyatt responsiveness index was 1.4, area under the curve was 0.83 (95% confidence interval: 0.72, 0.94), and the minimum clinically important difference corresponded to an increase of 7.1 percentile points. Standardized effect size of the Numeric Pain Rating Scale was 0.72, Guyatt responsiveness index was 2.2, area under the curve was 0.80 (95% confidence interval: 0.70, 0.92), and the minimum clinically important difference corresponded to a decrease of 1.16 points.
- Irrgang JJ, Snyder-Mackler L, Wainner RS, Fu FH, Harner CD. Development of a patient-reported measure of function of the knee. Journal of Bone Joint Surgery - American Volume 1998; 80-A(8):1132-1145.
- Piva SR, Gil AB, Moore CG, Fitzgerald GK. Responsiveness of the activities of daily living scale of the knee outcome survey and numeric pain rating scale in patients with patellofemoral pain. J Rehabil Med. 2009 Feb;41(3):129-35