The purpose of the present study was to demonstrate the reliability, validity, and responsiveness of the Activities of Daily Living Scale of the Knee Outcome Survey, a patient-reported measure of functional limitations imposed by pathological disorders and impairments of the knee during activities of daily living. The study comprised 397 patients; 213 were male, 156 were female, and the gender was not recorded for the remaining 28. The mean age of the patients was 33.3 years (range, 12 to 76 years). The patients were referred to physical therapy because of a wide variety of disorders of the knee, including ligamentous and meniscal injuries, patellofemoral pain, and osteoarthrosis. The Activities of Daily Living Scale was administered 4 times during an 8-week period: at the time of the initial evaluation and after one, 4, and 8 weeks of therapy. Concurrent measures of function included the Lysholm Knee Scale and several global measures of function. The subjects also provided an assessment of the change in function, with responses ranging from greatly worse to greatly better, at one, 4, and 8 weeks. The Activities of Daily Living Scale was administered to an additional sample of 52 patients (32 male and 20 female patients with a mean age of 31.6 years [range, 14 to 66 years]) before and after treatment within a single day to establish test-retest reliability. Factor analysis revealed 2 dominant factors: one that reflected a combination of symptoms and functional limitations and the other, only symptoms. The internal consistency of the Activities of Daily Living Scale was substantially higher than that of the Lysholm Knee Scale (coefficient alpha, 0.92 to 0.93 compared with 0.60 to 0.73), resulting in a smaller standard error of measurement for the former scale. Validity was 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). Analysis of variance with repeated measures revealed significant improvements in the score on the Activities of Daily Living Scale during the 8 weeks of physical therapy (F2,236 = 108.13; p < 0.0001); post hoc testing indicated that the change in the score at 8 weeks was significantly greater than the change at 4 weeks and that the change at 4 weeks was significantly greater than that at one week (p < 0.0001 for both). As had been hypothesized, the patients in whom the knee had somewhat improved had a significantly smaller change in the score, both at 4 weeks (F1,189 = 33.50; p < 0.001) and at 8 weeks (F1,156 = 22.48; p < 0.001), compared with those in whom the knee had greatly improved. 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.
Copyright remains with the authors and publisher.
The purpose of the present study was to demonstrate the reliability, validity, and responsiveness of the Activities of Daily Living Scale of the Knee Outcome Survey, a patient-reported measure of functional limitations imposed by pathological disorders and impairments of the knee during activities of daily living. The study comprised 397 patients; 213 were male, 156 were female, and the gender was not recorded for the remaining 28. The mean age of the patients was 33.3 years (range, 12 to 76 years). The patients were referred to physical therapy because of a wide variety of disorders of the knee, including ligamentous and meniscal injuries, patellofemoral pain, and osteoarthrosis. The Activities of Daily Living Scale was administered 4 times during an 8-week period: at the time of the initial evaluation and after one, 4, and 8 weeks of therapy. Concurrent measures of function included the Lysholm Knee Scale and several global measures of function. The subjects also provided an assessment of the change in function, with responses ranging from greatly worse to greatly better, at one, 4, and 8 weeks. The Activities of Daily Living Scale was administered to an additional sample of 52 patients (32 male and 20 female patients with a mean age of 31.6 years [range, 14 to 66 years]) before and after treatment within a single day to establish test-retest reliability. Factor analysis revealed 2 dominant factors: one that reflected a combination of symptoms and functional limitations and the other, only symptoms. The internal consistency of the Activities of Daily Living Scale was substantially higher than that of the Lysholm Knee Scale (coefficient alpha, 0.92 to 0.93 compared with 0.60 to 0.73), resulting in a smaller standard error of measurement for the former scale. Validity was 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). Analysis of variance with repeated measures revealed significant improvements in the score on the Activities of Daily Living Scale during the 8 weeks of physical therapy (F2,236 = 108.13; p < 0.0001); post hoc testing indicated that the change in the score at 8 weeks was significantly greater than the change at 4 weeks and that the change at 4 weeks was significantly greater than that at one week (p < 0.0001 for both). As had been hypothesized, the patients in whom the knee had somewhat improved had a significantly smaller change in the score, both at 4 weeks (F1,189 = 33.50; p < 0.001) and at 8 weeks (F1,156 = 22.48; p < 0.001), compared with those in whom the knee had greatly improved. 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.
Copyright remains with the authors and publisher.