Symptom assessment in knee XXXX needs to account for physical activity level.

@entity1 @entity571 @entity158
OBJECTIVE: @entity158 is not always correlated with severity of @entity571 ( @entity571 ), possibly because @entity1 modify activities to manage symptoms. Measures of symptoms that consider @entity158 in the context of activity level may therefore provide greater discrimination than a measure of @entity158 alone. We undertook this study to compare discrimination provided by a measure of @entity158 alone with that provided by combined measures of @entity158 in the context of physical activity across radiographic @entity571 severity levels. METHODS: This was a cross-sectional study nested within the @entity571 ( @entity571 ). The population was drawn from 2,127 @entity1 enrolled in an @entity571 accelerometer monitoring substudy, including those with and those without knee @entity571 . Two composite @entity158 and activity knee symptom (PAKS) scores were calculated as the Western Ontario and McMaster Universities @entity571 Index (WOMAC) @entity158 score (plus 1) divided by a physical activity measure (step count for the first PAKS score [PAKS1 score] and activity count for the second PAKS score [PAKS2 score]). Symptom score discrimination across Kellgren/Lawrence (K/L) grades was evaluated using histograms and quantile regression. RESULTS: A total of 1,806 @entity1 (55.5% of whom were @entity1 ) were included (mean        SD age 65.1      9.1 years, mean        SD body mass index 28.4        4.8 kg/m(2) ). The @entity158 score, but not the PAKS scores, exhibited a floor effect. The adjusted median @entity158 scores by K/L grades 0-4 were 0, 0, 0, 1, and 3, respectively. The adjusted median PAKS1 scores were 24.9, 26.0, 32.4, 46.1, and 97.9, respectively, and the adjusted median PAKS2 scores were 7.2, 7.2, 9.2, 12.9, and 23.8, respectively. The PAKS scores had more statistically significant comparisons between K/L grades than did the @entity158 score. CONCLUSION: Symptom assessments incorporating @entity158 and physical activity did not exhibit a floor effect and were better able to discriminate radiographic severity than an assessment of @entity158 alone, particularly in milder disease. @entity158 in the context of physical activity level should be used to assess knee @entity571 symptoms.
