Comparative Effect of Two Educational Videos for People With Knee Osteoarthritis (vidEO)

Self-efficacy is considered fundamental for effective chronic disease self-management and greater self-efficacy is related to higher physical activity levels in people with OA. Self-efficacy will be measured with the Arthritis Self-Efficacy Scale (ASES) (pain subscale). Range 0-10, higher scores mean better self-efficacy.

Kinesiophobia is the fear that movement will exacerbate pain. According to the fear-avoidance model, fear is worsened by heightened negative emotion and hypervigilance to symptoms. Kinesiophobia will be measured with the Brief Fear of Movement Scale for Osteoarthritis (BFMS). Range 6-24, lower scores mean better outcome.

The Credibility/Expectations Questionnaire, which was designed to measure expectation of benefit from therapy, was adapted to measure expectations about their knee OA prognosis and the perceived effect of physical activity.There are two parts, Part 1: range 3-27, higher scores better. Part 2: range 2-18, higher scores better.

Perceived importance of being physically active will be measured through rating the level of agreement with four statements. Likert scaling with 5 response options. Responses averaged so scores range 1-5. Two items reverse scored so that high scores indicate better.

Knowledge and beliefs about knee OA will be measured using the Knee Osteoarthritis Knowledge Scale (KOAKS). This scale has established content validity and is currently being examined for other psychometric properties. It currently has 15 items and scores range from 15-75 with higher scores indicated better knowledge, however, some items may be removed once reliability study is published.

Post-intervention change in feelings about having knee OA (specifically "How much have your feelings of hope for the future changed since watching the video?"), will be rated using a Likert scale with 5 response options. Responses will be dichotomised with participants indicating they are "somewhat more" or "much more" classified as 'more hopeful'. All other respondents classified as 'not more hopeful'.

Perceived personal chance of ever having surgery will be measured using 5 level Likert scale from very unlikely to very likely. Scores range 1-5 with lower scores being considered better.

Motivation to be physically active will be determined by asking participants to rate 'How motivated are you to be physically active (e.g., walk, run, swim, cycle, dance, exercise, etc) even when you are feeling knee pain?', on a scale from 0 (not at all motivated) to 10 (very motivated). This question is drawn from the Information-Motivation-Behavioural skills model of behaviour change, which explains that having the motivation to change is an essential determinant of behaviour that is independent of both knowledge and behavioural skills. Range 0-10 with higher scores indicating greater motivation.

Have you seen the video before? Yes/no

How many times did you watch the video before completing this questionnaire? 0 = Did not watch the video or only watched part of the video

• = Watched it once through to the end
• = Watched it more than once through to the end

How satisfied are you that the video helped meet your current needs for information about knee osteoarthritis? Single item Likert scale with 5 response options. Responses dichotomised to those indicating they are "moderately satisfied" or "very satisfied" classified as satisfied.