Effect of an information- and self-management app for people with knee osteoarthritis

Approved 24/09/2025, REK KULMU (Committees for Clinical Trials of Medicines and Medical Devices) (University of Oslo, Oslo, 0313, Norway; +4722850383; rek-kulmu@medisin.uio.no), ref: 938916

1. Osteoarthritis and treatment options measured using the Knee OsteoArthritis Knowledge Scale (KOAKS), at baseline, 8 weeks and post consultation
2. The patient's uncertainty with treatment options will be measured using the Decisional Conflict Scale (DCS), post consultation

Secondary outcome measures are assessed post consultation:
1. Concordance between preferences and treatment decision, measured with one question from the Decision Conflict Scale (DSC)
2. Decisional quality, measured with section 3 (decision process scale) in the Decision Quality Index for Knee Osteoarthritis (K-DQI)
3. Level of shared decision-making, measured with the CollaboRATE questionnaire
4. Satisfaction with treatment choice, measured on a numeric rating scale (0–10, with a higher score indicating more satisfaction)

Other outcome measures:
5. Motivation for exercise, measured on a numeric rating scale from 0 to 10 with higher score indicating higher motivation, at baseline, 4 weeks (only intervention group), and 8 weeks
6. Motivation for surgery, measured on a numeric rating scale from 0 to 10 with higher score indicating higher motivation, at baseline, 4 weeks (only intervention group), and 8 weeks
7. Assessment of knee-related pain, measured with the Knee Injury and Osteoarthritis Outcome Score (pain section), at baseline, 4 weeks (only intervention group), 8 weeks, 1 and 2 years
8. Assessment of knee-related function, measured with the Knee Injury and Osteoarthritis Outcome Score (function section), at baseline, 4 weeks (only intervention group), 8 weeks, 1 and 2 years
9. Assessment of knee-related quality of life, measured with the Knee Injury and Osteoarthritis Outcome Score (quality of life section), at baseline, 4 weeks (only intervention group), 8 weeks, 1 and 2 years
10. Health-related quality of life, measured with EQ-5D-5L, and a Visual Analog Scale (VAS) from 0 to 100, with 100 indicating best health, at baseline, 1 and 2 years
11. Level of shared decision-making therapist, measured with 7 statements from the MAPPIN'SDM Therapist, post consultation
12. Preferred decision-making role, measured with the Control Preference Scale, post consultation
13. Illness perception, measured with the Brief Illness Perception Questionnaire (B-IPQ) at baseline and 8 weeks
14. Pain self-efficacy, measured with the Pain Self-Efficacy Questionnaire (PSEQ-2) at baseline and 8 weeks
15. Pain catastrophizing, measured with one question about concern about pain, measured on a 0 (not at all) to 4 (all the time) scale at baseline and 8 weeks
16. Pain intensity, measured with four questions from the Brief Pain Inventory, assessed on numeric rating scales from 0 (no pain) to 10 (worst possible pain) at baseline and 8 weeks
17. Pain intensity now, measured with one question about pain intensity now on a numeric rating scale from 0 (no pain) to 10 (worst possible pain) at baseline, 4 weeks (only intervention group), 8 weeks, 1 and 2 years
18. Disease activity, measured with a numeric rating scale from 0 (no disease activity) to 10 (worst disease activity) at baseline, 8 weeks, 1 and 2 years
19. Fatigue, measured on a numeric rating scale from 0 (no fatigue) to 10 (worst possible fatigue) at baseline, 8 weeks, 1 and 2 years
20. Importance of treatment options, measured with five questions from the Decision Quality Index for Knee Osteoarthritis (section 1). Assessed on numeric rating scales from 0 (not at all important) to 10 (extremely important) at baseline and 8 weeks
21. Preferred treatment, measured with a question about whether they prefer surgery or non-surgical treatment at baseline and 8 weeks
22. Health literacy, measured with the HLS19-Q12 at baseline
23. Self-efficacy of digital solutions, measured with six questions about the self-efficacy of using different digital solutions (mobile phone, tablet, computer, apps, identification portal, helsenorge.no), assessed on a 6-point scale from never tried to manage very well at baseline
24. Previous treatment, assessment of previous treatment, answered with yes/no on questions related to previous physiotherapy treatment, previous osteoarthritis school at baseline
25. Health problems' impact on daily living, measured with one question from the Work Productivity and Activity Impairment questionnaire (WPAI) (question 6), answered on a numeric rating scale from 0 (no effect on daily activities) to 10 (completely prevented from doing daily activities) at baseline, 8 weeks, 1 and 2 years
26. Decision regret, measured with item 2 from the Decision Regret Scale, answered on a 5-point scale from totally agree to totally disagree post consultation
27. Use of pain medication, assessed with an open-ended question about the use of pain medication last three months (type and dosage) at baseline, 8 weeks, 1 and 2 years
28. Demographics, measured with questions about gender, age, education level, working status, smoking, living arrangements, socioeconomic status, and support at baseline
29. Anthropometrics, measured as self-reported height and weight at baseline
30. Joint-specific information, measured with questions about the most troublesome knee, duration of complaints, and other joints with complaints, at baseline
31. Exercise level, measured with one question about exercise level answered on a 5-point scale from do not exercise to exercise 3 or more times per week, at baseline, 8 weeks, 1 and 2 years
32. Comorbidities, measured with 15 questions about the presence of different diseases (yes/no), at baseline
33. Usability of the app, measured with System Usability Scale (SUS) comprising 10 statements answered on a 5-point scale from strongly disagree to strongly agree, converted to a 0–100 score with a higher score indicating better usability, at 8 weeks (only intervention group)
34. Satisfaction with the app, measured with two questions about the satisfaction with the information videos and exercise videos in the app, answered on numeric rating scales from 0 (not satisfied) to 10 (very satisfied), at 8 weeks (only the intervention group)
35. Suitability of the app, measured with two questions about the suitability of providing information and exercises through an app, answered on numeric rating scales from 0 (not suitable) to 10 (very suitable), at 8 weeks (only the intervention group)
36. Surgical treatment, measured with a question about whether the patient has undergone surgical treatment (yes/no) and for those answering yes, five questions about the improvement/satisfaction with the surgical treatment, on a 5-point scale from very satisfied to very dissatisfied, at 1 and 2 years
37. Healthcare costs and sick leave/disability benefits, measured using data collected from the register at 8 weeks, 1 and 2 years. Data will be collected from 1 year before inclusion